PAIN CONTROL AFTER THORACIC SURGERY

LITHUANIAN UNIVERSITY OF HEALTH SCIENCES

MEDICAL ACADEMY FACULTY OF NURSING

DEPARTMENT OF NURSING AND CARE

JOSSY ANNAMMA JOY

PAIN CONTROL AFTER THORACIC SURGERY

The graduate thesis of the Master‘s degree study programme “Advanced Nursing Practice” (State Code 6211GX008)

Tutor of the graduate thesis

Phd ,MD, Milda Švagždienė

TABLE OF CONTENT

1.2 Pain after thoracic surgery……….7

1.3Degree and duration of pain after thoracic surgery………...9

1.4Acute postthoracotomy……….10

1.5Chronic postthoracotomy pain ……….11

1.5.1Mechanism of postthoracotomy pain………...12

1.6Pain management after thoracic surgery………...12

1.6.1Systemic analgesia……….………13

1.6.2Regional Anesthesia Techniques………...17

2.ORGANISATION AND METHODOLOGY OF A RESEARCH………...30

3 RESULTS………...30

4 .DISCUSSION OF THE RESULTS………...32

CONCLUSIONS………35

PRACTICAL RECOMMENDATIONS………...36

PUBLICATIONS……… ..40

LIST OF LITERATURE SOURCES………...41

ANNEXES……….44 DECLARATION OF THE AUTHOR’S CONTRIBUTIONS AND ACADEMIC HONESTY

ABSTRACT

Jossy Annamma Joy. Pain control after thoracic surgery. The graduate Master’s thesis .The tutor-

PhD MD, Milda Švagždienė. Lithuanian University of Health Science,Medical academy,the Faculty of Nursing, Department of Nursing and Care.Kaunas,2019; 45p.

Thoracotomy is considered the most painful of surgical procedures and providing effective analgesia is the onus for all anesthetists. Ineffective pain relief impedes deep breathing, coughing, and remobilization culminating in atelectasis and pneumonia. Systemic opioid-based analgesic regimen often fails in the treatment of postoperative pain after thoracotomy and the prevention of persistent pain. AIM: * To find the optimal postoperative analgesia plan for the patients after thoracic surgery. GOALS: *To investigate the incidence, severity and duration of acute postthoracotomy pain. * To find the optimal analgesia method for the patient after thoracotomy. * To investigate different methods and regiments of analgesia. METHODS For this research, the literature search was conducted in the Pubmed, Science Direct, PLOS, SAGE, Google Scholar databases and 35 literature sources were reviewed. Studies published in English between 2009– 2019 have been reviewed.

CONCLUSION :After surgery, pain control is central to the anesthetic management of thoracic

surgical patients. The provision of good postoperative analgesia is important in itself and is regarded by some as the core business of anesthesia and a fundamental human right. Effective analgesia can reduce pulmonary complications and mortality. It is unlikely that a single technique will fulfill these goals optimally for all patients and that a balanced, multimodal approach should therefore be used. Analgesia should be tailored to the specific patient undergoing a specific procedure to minimize mortality, patient suffering, complications of the pulmonary system, and other morbidity. Experience with a wide range of analgesic techniques is helpful as it allows a suitable technique to be implemented. For open thoracotomies, a combination of regional analgesia and opioids, sometimes supplemented with non-opioid analgesics, will best manage most patients. Usually only consideration should be given to lumbar epidural analgesia, intrathecal opioids, or intercostal nerve blocks if no thoracic epidural analgesia or paravertebral blocks are possible. Currently the choice between thoracic epidural analgesia and paravertebral block is the dilemma for thoracic anesthetists and their patients scheduled to undergo thoracotomy.

ABBREVIATIONS

LA

:

TEA

PTPS : Post thoracotomy pain syndrome IV : Intra Venous

IM : Intra Muscular

PCA : Patient Controlled Analgesia

NSAIDs : Non Steroid Anti-Inflammatory Drugs COX : Cyclooxygens

TEA : Thoracic Epidural Analgesia ICNs : Intercostal nerves

ICNB : Intercostal Nerve Blocks TP : Transverse Process BR : Breathing Rate HR : Heart Rate

ABP : Arterial Blood Gas VAS : Visual Analogue Scale

INTRODUCTION

Thoracotomy is considered the most painful of surgical procedures and providing effective analgesia is the onus for all anesthetists. Ineffective pain relief impedes deep breathing, coughing, and remobilization culminating in atelectasis and pneumonia. This article reviews the mechanisms of acute and chronic thoracotomy pain, the risk factors, current analgesic options, and the role genetics may increasingly play in the management of thoracotomy pain.(1) Chest surgery may be either thoracotomy or thoracoscopy. The incision may be either muscle-cutting or muscle-sparing incision in thoracotomy. For most general thoracic surgical procedures, posterolateral thoracotomy incision is used. This incision, involving division of the anterior latissimus dorsi and serratus muscles, provides excellent thoracic cavity exposure. It is associated with significant morbidity, however, including impaired pulmonary function, postoperative chest pain, and limited movement of the arm and shoulder. Different muscle-sparing incisions were suggested to reduce morbidity. Postthoracotomy pain is caused during surgery by pleural and muscle damage, costovertebral disruption of the joint, and intercostal nerve damage.Inadequate pain relief after surgery affects the quality of patient's recovery and exposes the patients to postoperative morbidities. There is a tendency nowadays among thoracic surgeons and anesthesiologists toward the area of enhanced recovery after thoracic surgery which requires careful titration of the anesthetic drugs in awake patients undergoing thoracoscopic procedures. There is a common feeling among thoracic anesthesiologists that postthoracoscopy procedures produce less pain intensity versus thoracotomy which is partially true. Effective management of acute pain after either thoracotomy / thoracoscopy is needed, however, and can prevent these complications and reduce the likelihood of chronic pain developing. Adequate pain relief leads to early mobilization, improves breathing functions, and decreases the response of global stress. Therefore, good management of perioperative pain significantly reduces postoperative complications. Numerous analgesic methods are currently available to manage acute postthoracotomy / thoracoscopy pain, including patient-controlled analgesia, local anesthetic (LA) infiltration, intrapleural or intercostal nerve blockages, and neuraxial blockages. In this report, we examine the newly introduced modalities for pain relief postthoracotomy / thoracoscopy with particular reference to the new tendency

Systemic opioid-based analgesic regimen often fails in the treatment of postoperative pain after thoracotomy and the prevention of persistent pain. Therefore, multimodal strategies involving the use of regional and/or local anesthesia in combination with systemic analgesics are warranted and have been shown to reduce post operative pain and the development of chronic pain .(2)

One of the long-term complications of thoracotomy is chronic post-thoracotomy pain. It is defined as pain on the chest around the incision scar that persists for longer than 2months postoperatively, or that recurs after having disappeared for a while, but that is not related to the recurrence of a tumor or to an infection.(3)

According to various studies, the incidence of this pain is 22—67% . Pain is severe in 5—25% of these patients. The chronic pain disturbs daily activities of almost half of the patients, sleep is disturbed in one quarter of them . It has been suggested that the development of chronic post-thoracotomy pain can be prevented by treating acute postoperative pain effectively and by using good surgical techniques . According to several studies, thoracic epidural analgesia (TEA) is superior to less invasive methods in the management of acute post-thoracotomy pain. Today it can be considered a gold standard . Usually a combination of a local anaesthetic (bupivacaine, ropivacaine) and an opioid (fentanyl, morphine) is used(3).

Uncontrolled acute perioperative pain and related surgical stress responses are highly associated with poor outcomes after thoracotomy Effective analgesia reduces perioperative morbidity, shortens hospitalization times, improves patient satisfaction, and lowers cost these principles are long established and are now included in Joint Commission on Accreditation standards. Uncontrolled pain in the perioperative period consistently predicts the development of chronic pain. Strategies that emphasize pre-emptive analgesia may provide protection against chronic pain syndromes, with some evidence suggesting as high as a 50% reduction in the incidence of chronic pain syndromes at 1 year after thoracotomy. (et.al Brandi A. Bottiger,2014) (4)

AIM

To find the optimal postoperative analgesia plan for the patients after thoracic surgery.

GOAL

To investigate the incidence, severity and duration of acute postthoracotomy pain. To find the optimal analgesia method for the patient after thoracotomy.

1. REWIEW OF LITERATURE

1.1Definition of pain

Pain is defined as ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’ (International Association for the Study of Pain, Subcommittee of Taxonomy 1986b).

1.2Pain after thoracic surgery

Pain after thoracotomy arises from nociceptive and neuropathic mechanisms which may originate from somatic and visceral affer- ents. Pain can also be referred.(1)

Nociceptive somatic afferents are conveyed by the intercostals nerves after skin incision, rib

retraction, muscle splitting, injury to the parietal pleura, and chest drain insertion to the ipsilateral dorsal horn of the spinal cord (T4–T10). The afferents are then transmitted to the limbic system and somatosensory cortices via the contralateral anterolateral system of the spinal cord. Nociceptive

visceral afferents are conveyed by the phrenic and vagus nerves after injury to the bronchi, visceral

pleura, and pericardium.(1)

Neuropathic pain, After intercostal nerve injury, develops via the mechanisms and results in the

paradox of reduced sensory input (from touch, temperature, and pres- sure) with hypersensitivity (dysaesthesia, allodynia, hyperalge- sia, and hyperpathia).(1)

Referred pain

To the ipsilateral shoulder is common after thoracotomy and can often be unresponsive to the effects of thoracic epidural analgesia (TEA). Studies have demonstrated a reduction in shoulder pain by infiltrating local anaesthetic to block the phrenic nerve at the level of the pericardial fat pad, or alternatively by interscalene block. This suggests that irritation of the visceral pleura and pericardium, referred to the shoulder by the phrenic nerve, is the most likely source of this pain. As the nerves arise from C3 to C5, TEA is ineffective in blocking this pain. The phrenic nerve may also convey referred pain from transection of a major bronchus or irritation of the pleura from a chest drain placed too far into the apex of the hemithorax.(1)

Factors Influencing Pain After Thoracic Surgery

Surgical factors

The posterolateral thoracotomy approach provides the best access to surgery. It involves, however, dividing the latissimus dorsi and sometimes the anterior serratus and trapezius muscles, leading to one of the most painful surgical incisions. Many surgeons are now using alternative muscle-sparing approaches to replace muscle incision with dissection and reflection on the ribs. However, the

reduced field of view may result in excessive retraction of the rib, fracture, dislocation, costovertebral disruption, and intercostal nerves damage. These incisions may also span multiple dermatomes as opposed to the single dermatome of the posterolateral approach; for example, the axillary incision extends vertically downwards. Alternatively, an increasing number of video-assisted thoracoscopic surgery (VATS) is performed which may reduce acute pain if intercostal nerve damage is avoided by limiting the number and size of intercostal ports used. However, the incidence of chronic pain appears to be similar to open thoracotomy

Patient factors

The general surgical population suggests that patients who are young, female, with a history of depression and anxiety and are poorly informed of their management plan are more likely to experience acute post-operative pain.

Pre-operative Preparedness

Well-informed patients may experience less pain so that patients should be given full explanation of the proposed analgesic technique and its probable effects, including its limitations, potential side effects and complications.

Opioid Tolerance

Continuous exposure to opioids results in a right dose-response curve shift to opioids, resulting in patients requiring increased opioid levels to achieve the same pharmacological effect. It is a predictable adaptation of pharmacology. The degree of opioid tolerance is associated with the dosage, duration, and type of opioid given. Opioid tolerance is likely due to decreased sensitivity and density of opioid receptors, increased regulation of cyclic adenosine monophosphate and neural adaptation. N-methyl-d-aspartate (NMDA) receptor activation plays an important role in opioid tolerance development. Patients with opioid tolerance are relatively intolerant to pain and may be more difficult to cope with acute pain.

Sex

In an attempt to determine the influence of the patient's sex on the pain experienced after surgery, a considerable amount of work has been done. Female patients report more severe, frequent and diffuse pain than male patients with similar processes of disease. The difference in male - female pain perception decreases with age, was not found by all investigators and is usually only moderately large. Social gender roles have a significant impact on pain tolerance levels, are sometimes difficult to distinguish from the patient's sex, and may account for some of the

differences in gender pain tolerance. Coping strategies also affect pain tolerance of patients ; disaster response is associated with increased sensitivity to experimental pain. Women are more likely to be catastrophic, and this can help to account for the gender differences in pain tolerance.

Age

A recent systematic review found that young age was an important predictor of post-operative pain. Ageing can affect the pharmacokinetics of analgesic medicines and older people are considered more sensitive to systemic opioids. Likewise, there is a positive correlation between age and thoracic epidural spread with older patients requiring approximately 40% less epidural solution.

Surgical Approach

Sternotomy

After a sternotomy, the sternum is usually fixed internally with steel wire. Therefore, bone movement during respiration is minimal and usually only moderate post-operative pain. However, wide or inexperienced sternal distraction can fracture the sternum, strain or even interfere with anterior or posterior intercostal articulations with the potential to significantly increase postoperative pain experienced.

Video-Assisted Thoracoscopic Surgery

Video-assisted thoracoscopic surgery The extent of the surgical incision is limited and early postoperative pain can be reduced with video-assisted thoracoscopic surgery. These benefits can be reduced by using larger-diameter instruments and/or twisting surgical instruments against the ribs causing intercostal nerves to be injured and ribs to be bruised or even fractured. VATS is a type of minimally invasive chest thoracic surgery performed with a thoracoscope (small videoscope) using small incisions and special tools to minimize trauma. Other names for this procedure include thoracoscopy, thoracoscopic surgery or pleuroscopy. Three small (about1-inch) incisions are used during thoracoscopic surgery compared to one long 6-to8-inch chest incision used during traditional, "open" thoracic surgery. These small incisions insert surgical instruments and the thoracoscope.

As compared with traditional surgery, patients who undergo minimally invasive surgery experience:

 Decreased postoperative pain  Shorter hospital stay

Other possible benefits include reduced risk of infection and less bleeding.

Open Thoracotomy

Posterolateral Incision

Posterolateral incision is the classic thoracotomy approach as it provides good surgical access and can be easily extended if necessary. However, it involves cutting some of the major muscles in the chest wall and is considered to be one of the most painful surgical incisions. There is some evidence that divided ribs are internally fixed to reduce post-operative pain.

Muscle-Sparing Incision

Many surgeons now use one or more of the many described muscle-sparing incisions. A popular approach is the axillary muscle-sparing incision, the skin incision with obvious cosmetic advantages extending vertically down from the axilla. Although muscle-sparing incisions initially caused less perioperative pain, most studies did not find this reduction in peri-operative pain.

Anterior Incision

For certain cardiac and anterior mediastinal procedures, anterior incisions are used to provide access. However, due to the heart, exposure to lung surgery is particularly limited on the left. With this incision, rib resections are often performed to improve surgical access. Post-operative pain depends in part on the extent of excision and the extent of surgical retraction, but after a posterolateral thoracotomy it is similar to that. With this approach, intercostal nerve blocks are particularly effective because the incision does not involve any part of the chest supplied by the posterior skin nerves that originate from the dorsal rami and are not blocked by an intercostals nerve block.(5)

1.3 Degree and duration of pain after thoracic surgery

The degree of pain following thoracic surgery is usually classified as "severe." Pain after thoracotomy was described as one of the most severe postoperative pain modes, more than 70% of patients needed analgesics after thoracotomy during the immediate postoperative period.

The incidence and duration of pain indicates that postoperative pain occurs more frequently and is more severe following intrathoracic surgery (i.e. thoracotomy or sternotomy). The intensity of steady wound pain after thoracotomy was severe in 45-65% of patients and moderate in 25-35% of patients. Following sternotomy, steady wound pain in 60-70% of patients and moderate in 25-35% of patients was severe. Movement that places tension on the incision, such as deep breathing, coughing, or extensive body movements, increases pain intensity after intrathoracic operations. The

average duration of severe pain in this survey was 3 days after thoracotomy (range: 2-6 days) and 4 days after sternotomy (range 2-7 days).

The intercostal, vagus, and phrenic nerves convey noxious input associated with thoracic surgery to the central nervous system. Afferent phrenic activity is believed to be the source of shoulder pain that often accompanies thoracic procedures as phrenic but not suprascapular or epidural blockade curtails this. Intercostal nerve dysfunction resulting from incision, retraction, trocar placement, or suture is common and likely plays an important role in the thoracic surgery that accompanies pain. Furthermore, the need for constant respiratory effort and an increased pulmonary toilet creates an intense and relentless barrage of noxious input into the central nervous system. Initial reports showed that 50% of patients describe pain 1 year after thoracotomy, with many reporting pain even years later. Fortunately, if perioperative pain is handled aggressively, the prevalence of postthoracotomy pain may be modifiable, with rates as low as 21% one year after surgery. Surprisingly, video-assisted thoracic surgery (VATS) is associated with a prevalence of chronic pain comparable to that of open procedures, with pain rates ranging from 22% to 63%, likely due to intercostal nerve and muscle damage from insertion of trocars. Residual pain after surgery, on the other hand, is reported to be 25% after median sternotomy, stressing the role reduced intercostal nerve disruption and enhanced closure stability may contribute to chronic pain reduction. Several demographic and clinical factors help identify patients who are predisposed to chronic post-operative pain development. These include anxiety, depression, previous surgery, concurrent pain, lesions of the chest wall, youth, female sex, and increased levels of pain and analgesic use in the perioperative period.

1.4 Acute postthoracotomy pain

Severe acute pain after thoracotomy caused by retraction, resection, or fracture of ribs, dislocation of costovertebral joints, injury of intercostal nerves, and further irritation of the pleura by chest tubes is a normal response to all these insults .Acute pain after video-assisted thoracoscopic surgery is considered less severe. Suboptimal management of pain after thoracotomy (or after video-assisted thoracoscopic surgery in patients who have severely limited respiratory reserve) has major respiratory consequences. Inspiration is limited by pain, which leads to reflex contraction of expiratory muscles and consecutively to diaphragmatic dysfunction (decreased functional residual capacity and atelectasis, shunting, and hypoxemia). Moreover, most patients are early extubated to decrease the risk of pulmonary barotrauma (especially bronchial suture line "blowout") and to prevent respiratory sequelae such as pulmonary infection. The incision needs to be stretched deep breathing. Since this can be extremely painful, patients without adequate analgesia attempt to

prevent stretching of the skin incision by contracting their expiratory muscles, i.e. splinting, thereby limiting the stretch during inspiration on the incision. This failure to inspire deeply before a powerful exhalation leads to ineffective cough, which in turn promotes secretion retention, leading to the closure of the airways and atelectasis

1.5Chronic postthoracotomy pain

Postthoracotomy pain syndrome (chronic postthoracotomy pain or post-thoracotomy neuralgia, PTPS) is defined by the International Association for the Study of Pain as ‘‘pain that recurs or persists along a thoracotomy incision at least two months following the surgical procedure.’’ In general, it is burning and stabbing pain with dysesthesia and thus shares many features of neuropathic pain . PTPS is acknowledged increasingly by anesthesiologists and surgeons alike.(6)

Prevalence of post-thoracotomy pain

Chronic post-thoracotomy pain was commonly noted by surgeons during the Second World War in men who had had a thoracotomy for chest trauma; it was called chronic intercostal pain. Unfortunately, not much has changed since then, as the majority of patients do not seek help for their pain, but mention it only when specifically asked. Furthermore, despite a commonly held belief that post-thoracotomy pain is transient, there is no evidence that the pain experience decreases significantly over time. For example, incidence of long-term post-thoracotomy pain has been reported to be 80% at 3 months, 75% at 6 months, and 61% at one year after surgery; incidence of severe pain is 3–5%, and pain that interferes with normal life is reported by about 50% of patients .

Mechanism of postthoracotomy pain

There are several mechanisms for chronic pain after thoracotomy, and no consensus exists regarding causality.

Intercostal nerve damage Surgery

The intercostal nerve is routinely crushed by surgery, especially as the nerve is quite exposed on the rib's caudal side. When the chest is closed, it is also common for the nerve to be completely severed or included in a suture. Mechanical damage during rib resection and compression with a retractor are among the many possibilities of nerve injury. Incidental rib fractures may also immediately damage the intercostal nerve or interfere with an in tercostal nerve during healing, resulting in neuropathic pain symptoms. The sensation of pain in response to a normally non-painful stimulus

(allodynia) or an exaggerated response to a slightly painful stimulus (hyperalgesia), especially when accompanied by numbness, is considered to be diagnostic for nerve injury. These symptoms often occur along the intercostal nerves ' area of distribution / innervations and are the most common feature of post-thoracotomy pain.(6)

Tumor Recurrence

Many studies showed that increased pain could also be an early tumor recurrence.

Type of incision

The amount of postoperative pain has correlated many surgical techniques. Even muscle - sparing incisions appear to have no major advantage over posterolateral incisions Overall, subsequent pain has not been shown to be reduced by variations in surgical techniques.( 4,5)

1.6 Pain management after thoracic surgery

1.6.1 Systemic analgesia

Systemic analgesia may be divided into systemic opioids, non steroidal anti-inflammatory drugs (NSAIDs), paracetamol and ketamine. Opioids, NSAIDs, and ketamine can be delivered using intravenous, intramuscular or subcutaneous routes. Patient controlled analgesia devices (PCA) can be useful when administering intravenous opioids.

Combinations of NSAIDs and opioids or opioids and regional analgesia are also common.

Systemic opioids

Systemic opioids have been used as the cornerstone of postthoracotomy analgesia in the past; however, pain control has often been poor. As part of a multimodal strategy including nerve blocks, it is now appreciated that systemic opioids are best administered for open thoracotomies. Systemic opioid titration after thoracotomy is required if the balance between beneficial effects and detrimental effects (sedation and suppression of ventilation, coughing and sighing) is to be achieved. IV-PCA systems provide superior analgesia and enhance patient satisfaction compared to IM opioids. Partly because IV-PCA systems accommodate the multiple in post-operative opioid requirement between patient variation, halving opioid requirements approximately every 24 h post-operatively, and the small group of patients experiencing minimal post-operative pain.

NSAIDs

Analgesia is a cornerstone of postoperative therapy to reduce postoperative complications and stay in the hospital, not only for ethical reasons. Postoperative pain remains an unresolved problem despite all the advances in pharmacology therapy. Perioperative pain is a complex and multi-factorial phenomenon that often needs to be effectively controlled by combining several drugs with different mechanisms of action to mitigate the analgesic effects with each drug's synergism and additive effect, thereby reducing related analgesic side effects. The best choice for treating postoperative pain is a multimodal and multidrug approach. Different techniques and drugs are used: central and peripheral nerve blocks, opioids, NSAIDs, paracetamol, local anaesthetics, glucocorticoids and gabapentinoids. A single analgesic class is rarely adequate. The association is often used because some drugs have certain limitations such as ceiling effect, high-dose contraindication, respiratory insufficiency, liver damage, risk of upper gastrointestinal complications or kidney failure. For postoperative pain treatment, the concept of multimodal contest-sensitive analgesia is now well accepted. Different types of analgesics have been shown to be more effective than a single drug due to different mechanisms of action and can be used at low doses to reduce the incidence of side effects and to improve the quality of perceived analgesia. Many pharmacological trademarks have therefore introduced associations of analgesic drugs such as paracetamol plus tramadol, or codeine plus paracetamol and NSAIDs at a fixed dose whose association increases the analgesic effect for the different analgesic mechanism postulated.

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ketorolac provide pain relief by reducing prostaglandin production through cyclooxygenase (COX) inhibition and can be administered as adjuncts throughout the perioperative period, with their main benefit being effective pain relief without breathing depression. In one study of patients undergoing thoracotomy, the simultaneous use of NSAIDs reduced pain scores by about 60% and postoperative parenteral opioid consumption by 30%. Numerous NSAIDs for the 2 COX types (I and II) are available with varying selectivity; these can be administered perioperatively via oral or rectal routes. In particular, the convenience of preparing for intravenous administration during the intraoperative and immediate postoperative period resulted in ketorolac, a non-subtype selective COX inhibitor, being one of the most common NSAIDs administered perioperatively. Due to the potential for side effects, low risk of gastrointestinal bleeding, coagulopathy, acute kidney injury, and hypo perfusion should be considered for patients considered for NSAID analgesia.

Paracetamol—NSAIDs

Paracetamol is classified as mild analgesic and not as NSAID because its anti-inflammatory activity is weak. It is found that paracetamol in patients with thoracic epidural analgesia can decrease

post-thoracotomy ipsilateral shoulder pain when given preemptively and regularly during the first 48 hours postoperatively . The pain relief from NSAIDs is due to the inhibition of cyclooxygenase, an enzyme that is involved in the production of prostaglandins, prostacyclins and thromboxans, which are all involved in the generation of pain . The NSAIDs usually used for postoperative pain management are diclofenac, ketorolac, lysine acetyl salicylate, indomethacin, piroxicam, and tenoxicam. NSAIDs affect adversely the coagulation because they cause platelet dysfunction, making systemic bleeding more possible. This effect is independent from the route of administration. Among the others potential adverse effects, the renal dysfunction and the gastrointestinal bleeding are the most important . The patients with pre-existing renal disease, hypovolemia or treatment with loop-diuretics are more vulnerable to acute renal failure.

Intramuscular diclofenac 75 mg/12 h , rectally indomethacin 200 mg/24 h or continuous intravenous lysine acetyl salicylate (7.2 g/24 h) decrease the required quantities of morphine and the postoperative VAS scores. Indeed, the i.v. lysine acetyl salicylate was comparable with i.v. infusion of morphine (40 mg/24 h).

Opioid

Opioids are widely used for intraoperative and postoperative pain management and are commonly used for severe postoperative pain management. Opioids are versatile; delivery options for perioperative delivery include delivery of infusion to oral, intravenous, intramuscular, and neuraxial injection or catheter. When using an intravenous strategy, advanced days include quick initiation and titration facility. In order to minimize over sedation, a patient-controlled analgesic system can be programmed to deliver a baseline continuous infusion of a drug with patient-delivered or patient-patient-delivered doses alone. Patient satisfaction with this strategy rivals neuraxial analgesia, although opioid side effects must be cared for by the perioperative care team.

It has been shown that epidural analgesia is superior to i.v. Morphine through devices for patient-controlled analgesia (PCA). In addition, when used as sole agents, the doses of opioids required to produce comparable analgesia also produce significant respiratory depression; therefore, opioids are relegated mainly to adjuncts to a regional technique. The major drawback of opioids used for postoperative pain treatment is the narrow therapeutic window, resulting in nausea, vomiting, somnolence, or even moderate doses of respiratory depression. In addition, patients undergoing chronic opioid therapy may develop tolerance to these drugs, making it more difficult to relieve pain with their use.

In that case, the use of gabapentin may provide preventive analgesia, limiting the incidence in these patients of Chronic Post - Operative Pain Syndrome. The i.v. combination Opioids and i.v. NSAID

With satisfactory anticoagulation and renal function safety, it has become popular. In addition there are other regional alternatives that can be used in effective combination with the systemic use of opioids, such as the intercostal, intrapleural, intraspinal and paravertebral blockade with the use of local anesthetics.

Ketamine

Ketamine is a non-competitive antagonist which blocks the ion channel associated with NMDA receptor. By this way the central hyperexcitability of dorsal horn neurons is blocked. The activation of NMDA receptor plays an important role in post injury central sensitization and hyperalgesia, suggesting that systemic ketamine may be used effectively in treating postoperative pain . After thoracic surgery, i.m. administration of ketamine 1 mg/kg resulted in similar pain scores and in weaker respiratory depression in comparison with i.m. pethidine 1 mg/kg . Ketamine is capable of decreasing significantly immediate post-surgical pain after thoracotomy, but has no benefits in preventing chronic pain measured in long-term follow up (post thoracotomy pain syndrome).

Intravenous administration of ketamine at induction dose 1 mg / kg, followed by infusion at intraoperative dose 1 mg / kg /h and 1 mg / kg/24 h postoperatively improved immediate postoperative pain, but failed to control chronic pain development at 1-2, 6 weeks and 4 months after surgery. Similar results are generated from the addition of epidural ketamine (1.2 mg / h) to levobupivacaine and fentanyl preventive epidural analgesia. No difference was observed between the two groups in the incidence of chronic post-thoracotomy pain at 3 months .

Noxious inputs of pain cause prolonged firing of nociceptors of C-fibre resulting in glutamate release. Glutamate is a major exciting transmitter in the central nervous system that activates postsynaptic NMDA receptors that contribute to pain treatment and pain phenomena such as wind up and neural plasticity of the spinal cord. Enhanced activation of the NMDA receptor plays a role in inflammatory and neuropathic pain and results in secondary hyperalgesia activation and exacerbation. Since ketamine blocks the NMDA receptors, its administration before the noxious stimulus (thoracotomy) may prevent the central sensitization of pain (pre-emptive effect).

The clinical effect was better pain control as shown in the first 48 postoperative hours by lower VAS scores in ketamine compared to placebo group. While VAS score was only measured at rest and not at movement, ketamine also provided pain relief during chest wall mobilization in theory. Ketamine compared with placebo group presented a lower trend of chest drainage duration and of atelectasis that required bronchoscopic aspiration. In theory, the better control of pain during the mobilization of chest wall allowed efficacious cough with a rapid re-expansion of the lung and an early surgical recovery. Pre-operative administration of ketamine may be an effective adjunct to i.v.

Opioid analgesia in pain management with acute post-thoracotomy. Patients with ketamine experienced a significant reduction in pain scores, inflammatory response and morphine intake compared to placebo. Thus, the preventive administration of ketamine followed by i.v, in line with a philosophy of multianalgesic treatments of post-thoracotomy pain. In situations where epidural analgesia or other analgesic procedures differ from i.v., morphine analgesia may be clinically relevant. Analgesia with opioids is not available or contraindicated.

1.6.2 Regional Anesthesia Techniques

In thoracic surgeries, regional anesthesia plays an important role. After thoracic surgery, severe pain is common. Regional anesthesia results in better pain control, better stress response control, and lower respiratory complications compared to systemic opioid analgesia. This will improve overall patient outcomes.

Furthermore, chronic pain following thoracic surgery is common and may persist for several years, this complication may be reduced by using regional analgesic techniques. Non-intubated surgery with regional anesthesia has recently been reported for high-risk patients. There are several techniques for thoracic surgery for regional anesthesia.

Regional anesthesia techniques for patients undergoing thoracic surgery can provide excellent pain management. Because of their superior track record of pain control and improved results, both thoracic epidural analgesia and paravertebral analgesia are often considered optimal modalities for postthoracotomy analgesia. Other regional technologies, including but not limited to intrathecal opioid analgesia, intercostal nerve block (ICNB), intercostal cryoanalgesia and intrapleural analgesia, can help improve pain scores and reduce opioid use.(2)

Anatomy Crucial To Thoracic Surgery

Thoracic surgery involves several nerves. The intercostal nerve at the incision site and ribs is the most important component in the skin and muscles. Damage to the intercostal nerve can lead to chronic pain, and regional anesthesia should block nociceptive transmission through the intercostal nerve. The vagus and phrenic nerves are associated with mediastinal and diaphragmatic pleura pain stimuli, and after surgery the brachial plexus is associated with shoulder pain. Therefore, multimodal analgesia with opioids and non-steroidal anti-inflammatory drugs (NSAIDs) should be considered together with the use of regional analgesia techniques. The intercostal nerve runs between the muscle and pleura of the internal intercostal. The intercostal nerve block (INB) involves a distal approach to the intercostal nerve, whereas a more proximal approach is involved in the thoracic paravertebral block (TPVB). TPVB provides multi-segmental intercostal nerve

blockade as well as sympathetic block; therefore, it is a good alternative for epidural analgesia for thoracic surgeries.

The first choice of regional thoracic surgery anesthesia is epidural analgesia. Recently ultrasound-guided TPVB is a good alternative when patients receiving anti-coagulant therapy or those with bleeding tendencies are contraindicated with epidural analgesia. Although TPVB is safer for these patients than epidural analgesia, care should be taken to select it. The intercostal nerve block or interpleural block may be considered when these two blocks are contraindicated.

Thoracic Epidural Analgesia

A thoracic epidural injection is a shot that temporarily contributes to thoracic region pain relief. That's the back's upper to middle. Medicine is injected into a spinal cord area. This area is referred to as the epidural space. The spinal cord is a delicate bundle of nerves running from the lower back to the brain. The spinal cord nerves enable the brain to communicate with the rest of the body. The spinal cord is surrounded by the epidural space. The column of many small bones (vertebrae) is the hard structure of the spine or backbone. The spinal column bones help protect the spinal cord against injury. There are intervertebral disks between these bones. These disks are cushioning the vertebrae. They also provide flexibility for the backbone. Nerves that leave the spinal cord may get pinched or inflamed at times. For example, this could happen when part of an intervertebral disk presses into the spinal cord and nerves space.

Indications

Thoracic epidural analgesia continues to be a key component of acute pain services based on anesthesia and is used after thoracic surgery, abdominal surgery, and rib fractures to treat acute pain. TEA is warranted when a thoracic or upper abdominal incision is expected to be moderate to large. In fast-track surgery, TEA can also be a useful adjunct by optimizing pain relief, attenuating the response of surgical stress, and allowing early mobility. TEA with local anesthetic is an important component of colorectal fast-track procedures as it reduces postoperative ileus duration. Provides a comprehensive list of open surgical procedures in which postoperative pain can be treated with TEA. There is no unique TEA contraindication that is not applicable to all neuraxial procedures. TEA is widely used thoracotomy analgesic technique. Inserting a thoracic epidural before general anesthesia facilitates patient feedback on improper placement and allows evaluation of its effectiveness. The insertion point is usually at the level of T5–T6 midway along the dermatomic distribution of the incision thoracotomy. Due to the steep caudal angulation of the spinous processes at this level, difficulties in locating the epidural space are often encountered;

therefore, some anaesthetists prefer a paramedic approach that avoids spinous processes. Because of its proven record of excellent dynamic pain relief and prevention of postoperative pulmonary complications, TEA has long been considered the gold standard regimen for patients undergoing thoracic operations. Epidurals can be placed eitherpre-operatively or post-operatively, depending on the size of the surgical incisions (VATS vs thoracotomy) and the patient's tolerance (opioid-dependent vs naive). Although the timing of initiation of TEA remains controversial, it has been shown that its continuous use for at least 48 hours postthoracotomy provides the benefits of optimal pain control and improved results. Our typical practice is to keep epidurals in place until drains from the chest tube are removed.

The shoulder pain reported by patients with thoracotomy is mostly referred to as pain, and epidural analgesia does not cover it. Most surgeons would agree that shoulder pain is a major problem of postoperative pain that deserves particular attention.

Shoulrer Pain

More than 75% of patients with thoracotomy report constant severe ache in the post-surgery ipsilateral shoulder. This pain is relatively resistant to opioids intravenous and is only partially relieved through NSAIDs. Postulated mechanisms include transection of a major bronchus, ligamentous strain caused by malposition or surgical mobilization of the scapula, pleural irritation caused by the thoracostomy tube, or referred pain caused by pericardial irritation or mediastinal and diaphragmatic pleural surfaces. Several methods with varying results have been investigated. There was no effective pain relief intrapleural bupivacaine. Superficial cervical plexus or brachial plexus blocks in some patients effectively reduced localized shoulder pain, whereas suprascapular nerve block was not helpful. Through intraoperative infiltration of the periphrenic fat pad with lidocaine, the incidence of shoulder pain decreased from 85% to 33% and the overall pain scores decreased. Ropivacaine reduced incidence by 0.2 percent and postoperatively delayed the onset of shoulder pain for the first 24 hours without adverse effects on respiratory function. It appears that pain can be referred to as the main source of shoulder pain via the phrenic nerve (blocked by periphrenic infiltration and interscalene brachial plexus block) with a contribution from positioning and surgery (coracoid impingement syndrome and coraco-clavicular ligament strain), partially relieved by the use of NSAIDS) and acetoaminophen. However, pain was still reported by some patients who received phrenic nerve infiltration. This may be due to anatomical variations in the emergence of phrenic nerve sensory fibers, reaching the pleura's fibrous pericardium and parietal layers The most effective management strategy would be multimodal, consisting of acetoaminophen (preventive and

regular), if not contraindicated NSAIDS, and long-acting local anesthetic infiltration of the phrenic nerve.

Intercostal Nerve Blocks

Intercostal nerve blocks are simple to perform and useful for pain management either as the primary intervention or as adjuncts. They are useful for pain in the chest wall and upper abdomen. The intercostal nerves (ICNs) intimate the major parts of the skin and musculature of the chest and abdominal wall. In the 1940s, clinicians noticed that intercostal nerve blocks (ICNBs) may reduce pulmonary complications and opioid requirements after upper abdominal surgery. Continuous ICNB was introduced in 1981 to overcome the issues associated with repeated multiple injections. Today, ICNB is used in a variety of acute and chronic pain conditions that affect the thorax and upper abdomen, including breast and chest wall surgery. In addition, it facilitates its practice by introducing ultrasonic guidance to regional anesthesia practice.

Indications

 Incisional pain from thoracic surgery  Analgesia for thoracostomy

 Herpes zoster or post-herpetic neuralgia  Rib fractures

 Breast surgery

 Upper abdominal surgery

 Differentiating between visceral and somatic pain

Contraindications

Patient refusal for the procedure and active infection over the injection site are the only absolute contraindications. Other relative contraindications include local anesthetic allergy, prior nerve injury or damage, patient's inability to consent to the procedure, anticoagulation or coagulopathy. The expected results of the intercostal nerve block and relevant potential complications should be advised to patients. If patients have prior nerve injury or neuromuscular disease involving the area to be blocked, special consideration should also be given.

Equipment

Equipment includes:  Skin antiseptic  Sterile towels  Sterile gauze

 50 cm 22 g needle for local anesthetic injection  25 g needle for skin wheal

 Local anesthetic  Sterile gloves  Ultrasound machine  Marking pen

 ECG monitor

 Blood pressure monitor  Pulse oximetry

Generally, to maximize pain control, a long-acting local anesthetic such as 0.2% ropivacaine or 0.25% bupivacaine is chosen. It may be considered that continuous blocks with a nerve catheter are rarely used for this particular nerve block. Because of the high degree of local anesthetic intake from the intercostal space, local anesthetics can be considered and the maximum dosage allowed should be calculated, especially if multiple levels are to be blocked.

Technique

Successful intercostal nerve block results in local anesthetic being deposited outside the parietal pleura in the intercostal sulcus. Correct positioning will result in ipsilateral numbness of the blocked individual intercostal levels. Unless a large amount of local anesthetic is injected or the needle placed too close to the midline resulting in spread to the paravertebral space, it is rare for the blockade to extend to higher or lower levels. The block level is usually determined by the number of blocks performed and is restricted to the dermatome of the targeted intercostal nerves.

The spinal cord's nerves split into a dorsal ramus. The upper 11 ventral thoracic rami is the intercostal nerve running between the ribs in the intercostal spaces. Each intercostal nerve provides a lateral cutaneous branch that pierces proximal intercostal muscles to the rear axillary line to provide the chest wall's lateral aspect. Therefore, to ensure that the lateral cutaneous branches are blocked and thus the lateral aspect of the chest wall, it is important to block the intercostal nerves posterior to the posterior axillary line. The thoracic dorsal rami passes backwards near the vertebrae to provide the cutaneous innervation to the back. The dorsal rami is not blocked by an intercostal nerve block. This limits the effectiveness with intercostal nerve blocks of posterolateral thoracotomies. The intercostal nerves can be easily blocked under direct vision, while the chest is open, but due to the relatively short half-life of most local anesthetics, repeated percutaneous blocks are usually required. Although the position of intercostal nerves within the intercostal space varies considerably, intercostal nerves consistently lie in a plane deep within the intercostal muscle.

A small (5 ml) bolus of local anesthetic deposited in the proper plane blocks the appropriate intercostal nerve. Larger doses can also block adjacent intercostal nerves by spreading medially or directly to adjacent spaces. The systemic take-up of local anesthetics from the highly vascular intercostal space is rapid and the dose of local anesthetics administered by this route needs to be adequately restricted. Intercostal nerve blocks significantly reduce the need for postoperative pain and analgesic post-thoracotomy.

Complication

To avoid infection, care should be taken to perform this block using sterile technique. In order to reduce the risk of bleeding, the history of coagulopathy or anticoagulation should be discussed. Performing this block wake may alert the provider to pneumothorax or intraneural injection symptoms that may go unnoticed in a patient with sedation or anesthesia. Pneumothorax is rare and usually requires only monitoring, although providers should be prepared to decompress needles or insert a chest tube if necessary. Fortunately, local anesthetic systemic toxicity is also a rare occurrence. However, this region's local anesthetic take-up is high, and providers should be able to recognize last and provide adequate treatment. Using diluted local anesthetic concentrations and keeping the total dose below the maximum permitted dose will reduce the risk of systemic toxicity. Several inadvertent spinal case reports were described after intercostal nerve block. This is thought to be secondary to local anesthetic spreading through the dura medially, or to the rare occurrence of injection into a dural sac described as protruding from the vertebral foramen laterally. In order to try to exclude these complications, aspiration to exclude intravascular, intrapleural or intrathecal injection should be performed before injection, but negative aspiration is not a guarantee. Patients should be monitored for 20 to 30 minutes after the block has been removed.(7)(8)

Paravertebral blockade

Paravertebral blocks can be performed as so-called "single-shot" blocks, with the introduction of a single dose of long-acting local anesthetic, or they can take the form of a continuous block, by placing a catheter that allows local anesthetic infusion. Continuous thoracic paravertebral blocks can provide excellent post-thoracotomy analgesia, and several studies have shown that analgesia is comparable to that provided by thoracic epidurals but with fewer complications such as urinary retention, hypotension, nausea, vomiting, and pruritis and less perioperative hemodynamic instability.

 PVBs can be performed in the cervical and lumbar regions but there is no direct communication between adjacent levels in these areas. Most PVBs are therefore performed at the thoracic level.

 The thoracic paravertebral space is wedge shaped in all three dimensions.

 Medially: The bodies of the vertebrae, intervertebral discs, and intervertebral foraminae.

 Anterolaterally: the parietal pleura and the innermost intercostal membrane.

 Posteriorly: the transverse processes (TPs) of the thoracic vertebrae, heads of the ribs, and the superior costotransverse ligament.

 The paravertebral space contains spinal nerves, white and grey rami communicantes, the sympathetic chain, intercostal vessels, and fat.

Indications

Paravertebral nerve blocks are indicated for surgical procedures requiring unilateral analgesia or anesthesia. Common cases benefitting from unilateral paravertebral blocks are breast surgery, thoracotomy, herniorrhaphy, open cholecystectomy, and open nephrectomy. Bilateral paravertebral blocks can be a viable option for midline abdominal surgery. The clinician may consider thoracic paravertebral blockade over thoracic epidural analgesia in patients for whom bilateral sympathectomy and subsequent hypotension would be especially detrimental. For example, the use of thoracic paravertebral blockade in a patient with severe aortic stenosis has been reported. In another study, thoracic paravertebral blockade resulted in more stable hemodynamics and equivalent analgesia when compared to thoracic epidural analgesia in thorocotomy patients. However, because bilateral spread can occur , which may cause hemodynamic compromise similar to epidural blockade. Another unique feature of thoracic paravertebral blockade compared with thoracic epidural analgesia is the relative safety when performing these blocks on patients with a marginal coagulation cascade. This does not mean, however, that thoracic paravertebral blockade can be performed on patients with coagulopathy without caution. According to the American Society of Regional Anesthesia and Pain Medicine’s evidence-based guidelines, in the patient receiving antithrombotic or thrombolytic therapy, the exact same precautions should be taken when placing thoracic paravertebral blockade as when placing an epidural. However, if bleeding occurs in the thoracic paravertebral space, significant blood loss will be the likely complication rather than epidural hematoma and neurologic deficit.

Methods Of Performing Paravertebral Blocks

Several approaches to access the paravertebral space are described, and they can be widely divided into those performed preoperatively using landmark or ultrasound-guided techniques and those

performed intraoperatively under direct vision. The patient can be positioned either sitting or in the lateral decubitus position when blocks are performed in the awake patient. The anesthetized patient is usually positioned in the lateral decubitus position after anesthesia induction, with the side to be blocked at the top. Blocks should generally be performed at the level of the intended incision(s) described, due to the more caudal position of the ports, for thoracoscopic surgery, performing blocks and inserting catheters at T5/6 for upper / middle lobe surgery and T6/7 for lower lobe operation.

Ultrasound-Guided Methods

Percutaneous paravertebral thoracic blocks are technically easy to perform but have a failure rate of up to 10 %. Using the guidance for ultrasound may result in lower failure rates. Ultrasound-guided paravertebral thoracic blockade can be divided into in-plane techniques where the needle's long axis is fully visualized as it traverses the ultrasound plane to the target and out - of-plane techniques where the needle enters the skin away from the probe and across the scanning plane, allowing it to be visualized only in its short axis. The approach can be either in the plane of transversal or sagittal. The most frequently performed blocks described are using a linear ultrasound transducer and this is reflected in the accompanying images. Some groups advocate using micro-convex array transducers to enable deeper structures to be better imaged. For all techniques, correct identification of landmarks is essential, although their appearance will vary depending on the transducer's orientation. Published a detailed description of the para-vertebral space's ultrasonographic anatomy and its adjacent tissues.(9),(16)

Open Methods

It has been shown that placing a paravertebral catheter through a percutaneous approach is challenging and the catheter tip's eventual position is unpredictable. The position of paravertebral catheters in cadavers was assessed with ultrasound guidance Only 60 percent of catheters were positioned as intended. Twenty percent had passed into the pre tebral space before the vertebral bodies, 15 percent had passed into the soft tissue after the vertebral bodies, and 5 percent had passed into the epidural space. Thus, while catheters can be percutaneously placed in the paravertebral space, it may be more appropriate for the surgeon to insert the catheter under direct vision in the paravertebral space while the chest is open. Direct placement facilitates the catheter's clear progression along the paravertebral space to create a narrow longitudinal pocket that can block enough dermatomas to provide adequate analgesia.(10)

Advantages Of Thoracic Paravertebral Block Technical

 Simple and easy to learn

 Safer and easier than thoracic epidural

 Palpation of rib not necessary and scapula does not interfere with block

 Safe to perform in sedated and ventilated patients

 Catheter placement under direct vision during thoracic surgery is safe and accurate

 Chest drain loss of local anesthetic is four times lower than that of interpleural block

Clinical

 Single injection produces multi dermatomal ipsilateral somatic and sympathetic nerve block

 Reliably blocks the posterior primary ramus

 Abolishes cortical responses to thoracic dermatomal stimulation

 Inhibits stress and pressor response to surgical stimuli

 Maintains hemodynamic stability

 Reduces opioid requirements

 Low incidence of complication

 Preserves bladder sensation

 Preserves lower limb motor power

 Promotes early mobilization

 No additional nursing vigilance required

Complications

Complications of paravertebral nerve blocks may include the following:

 Failed block

 Hypotension

 Vascular puncture

 Pleural puncture

 Pneumothorax

Intradural opioid analgesia

Intrathecal opioid administration can provide an excellent method of controlling acute postoperative pain and is an attractive analgesic technique as the drug is directly injected into the

CSF, near the central nervous system structures where the opioid acts. The procedure is simple, fast and the risk of technical complications or failure is relatively low. In the intradural route, a lipophilic opioid such as fentanyl (20-40 μg) and/or a hydrophilic opioid such as morphine (100-300 μg) are increasingly associated with opioids of different characteristics. In the form of a pre-operative bolus with LA to ensure coverage during both the immediate (2-4 h) and the late (12-24 h) post-operative period. The association of a lipophilic opioid with bupivacaine or lidocaine leads to a shortening of the block's onset and an improvement in intraoperative analgesia, as well as during the first hours of the postoperative period without prolonging the engine block or extending the discharge time, making it a good choice for outpatient surgery.

The use of intrathecal medicines in the treatment of acute pain, a maximum effective dose of morphine has been recommended, the negative effects of which seem to exceed the beneficial effects ; after doses > 300 μg, nausea and itching usually appear, as well as severe urinary retention, and in studies of healthy volunteers, all of them with respiratory depression when doses exceeded 600 μg.

Pain Relief after Thoracic Surgery

Continuous thoracic paravertebral infusion of local anesthetics through a catheter placed under direct thoracotomy vision is a safe, simple and effective method for post-thoracotomy analgesia. Usually used in adults in conjunction with adjunct medicines (opioid or non-steroidal anti-inflammatory medicines) to provide optimal pain relief after thoracotomy. Although additional analgesics are required, there is a significant reduction in opioid requirements. A continuous thoracic paravertebral infusion of local anesthetic together with adjunct medicines provides very effective pain relief with few side effects. Pain relief is superior to placebo and patient-controlled morphine intravenous and comparable to interpleural analgesia, lumbar epidural morphine, and bupivacaine or bupivacaine fentanyl mixture thoracic epidural administration. Paravertebral analgesia thoracic preserves better respiratory function and produces fewer side effects than analgesia interpleural. There is also less frequency of hypotension and urinary retention than thoracic epidural analgesia. Local anesthetic continuous thoracic paravertebral infusion provides better control of pain after thoracotomy than an intermittent regimen of bolus. It reduces postoperative decline in respiratory function, increases breathing mechanics recovery, and reduces chronic postthoracotomy neuralgia generation. A balanced analgesic regimen, which includes preoperative pain prophylaxis (opioid and non-steroidal anti-inflammatory drug premedication with pre-incisional TPVB) in conjunction with postoperative paravertebral thoracic infusion of bupivacaine, regular nonsteroidal anti-inflammatory drug and opioid on-demand, is very effective

in patients with thoracotomy. It prevents postoperative plasma cortisol increase preserves preoperative respiratory function, and is superior to a balanced analgesic regimen with thoracic epidural bupivacaine. (11),(19)

Infiltration Of Surgical Wound With Local Anesthestics

Now an integral part of modern anesthetic practice is effective postoperative pain management. Management of postoperative pain not only minimizes patient suffering, but can also reduce cardiorespiratory morbidity and facilitate rapid recovery. Early hospital discharge has a beneficial effect on the costs of hospitals. While regional anesthetic techniques such as epidural analgesia or perineural catheters have been shown to provide excellent analgesia, many of these analgesic methods are time-consuming, expensive, and not without side effects. Since a significant proportion of surgical pain is caused by the surgical wound, it would appear logical to use local anaesthetics at the surgery site to manage perioperative pain. Local anesthetic has been used for many years for simple incisional infiltration. Promising advances that may help improve this technique are the use of longer-acting local anesthetic agents or placing a catheter directly in the wound at the end of the procedure to infuse local anesthetic.(10)(21)(25)

Methods of local anaesthetic infiltration

In recent years, an important component of multimodal analgesia has been the infiltration of local anesthetic around the surgical wound. It offers simplicity and low cost advantages. However, it has one major drawback: analgesia duration is limited to local anesthetic action duration. For bupivacaine and ropivacaine, this tends to be 4–8 h. The procedures in which incisional infiltration appears to be particularly helpful1 are those in which there is a smaller component of visceral pain, such as inguinal herniotomies in which pain scores were reduced for up to 24 hours and pain consumption decreased overall. Following minor day surgery, local anesthetic infiltration has been shown to reduce postoperative nausea and vomiting by reducing opioid requirements.(26)

Continuous Local Anaesthetic Wound Infiltration

The short-term problem of analgesia associated with incisional infiltration can be overcome by providing a continuous infusion of a local anesthetic. The surgeon places a catheter directly in the wound at the end of the surgical procedure. This is then attached to a pump that allows the infusion of a predetermined amount of local anesthetic into the wound per hour.

Table1 Comparison of The Different Methods of Local Anaesthetic Infiltration

Local anaesthetic infiltration method

Advantages Disadvantages

Single dose Simple low cost; very useful for small procedures

Limited efficacy; short duration of action; potential for adverse local toxic effects

Continuous infusion catheter

Prolonged provision of analgesia; less PONV as opioid sparing; no motor block; decreases hospital stay

Needs skills and resources; catheter dislodges easily; wound site leakage and potential for infection; technical failure of pumps; potential for adverse local toxic effects

Tumescent Simple; low cost; improved analgesia and prolong duration; allows larger dose.

Limited to selected types of surgery; potential for systemic local anaesthetic toxicity if poor technique or very large doses

Sustained release LA Simple to administer; prolonged provision of analgesia

Not commercially available (currently phase 1–3 drug trials); delayed onset of analgesia; unsteady levels in experimental formulations; unnecessarily long duration in some formulations

Infiltration of local anesthetic at the site of surgical incision offers a rational approach to perioperative analgesia. Unfortunately, due to the unfavorable pharmacokinetics of local anesthetics, this technique is limited by a short duration of action. However, the idea of incisional infiltration has been further developed and newer techniques such as continuous local anesthetic wound infiltration systems, tumescent techniques, and sustained release local anesthetics have been developed.There remain more details to be learnt with regard to these techniques, particularly in relation to optimal dosing regimens, optimal placement, use of analgesic adjuvant, and whether local toxic effects are more than a theoretical concern. However, given the relative simplicity and potential efficacy of these techniques, they are certainly worthy of consideration and continued investigation to define their role as a technique for perioperative analgesia.(10)(33)

Patient controlled analgesia (PCA)

PCA can approach the near optimal state of analgesia, maintained with minimum sedation and side effects. The patient adjusts the repetition of dose to the analgesic needs, outreaching the minimum effective analgesic concentration. Toxic drug concentrations cannot be reached because the subsequent sedation acts prophylactically by stopping the dose repetition from the patient.

PCA can be used for drug delivery via intravenous (most frequently) or epidural route. PCA is not a good analgesic alternative if the patient is confused and not capable of using the PCA pump handset. Before the initiation of PCA use, a sufficient analgesic state should be established.

In the case of epidural PCA, a solution of L-bupivacaine 0.125 with fentanyl 4 mcg/mL gives satisfactory analgesia. The bolus dose should be 3-5 mL, the lockout period 10-15 min with no background continuous infusion. If the latter is the case, then the bolus dose should be decreased and the lockout period increased!

If PCA is used for intravenous drug administration, it is commonly combined with paravertebral or intercostal nerve blocks. Otherwise, the systemic opioids side effects may limit the dosage, resulting in suboptimal analgesia with subsequent respiratory complications in thoracotomy patients. The bolus doses could be morphine 1-2 mg, fentanyl 10-20 mg, pethidine 10 mg or tramadol 10 mg. The lockout time should not be less than 5-8 min according to the above doses. The background infusion may increase the incidence of respiratory depression and is useful only in opioid tolerant patients.(26)(34)(35)

The major concern with the function of PCA is the respiratory depression. The risk is increased if there is a background infusion, in elderly patients, if concomitant sedatives are administered, in respiratory disease, in obstructive sleep apnea, and if there are operator or equipment errors. The administration of bolus naloxone 400 mg i.v. or more reverses the respiratory depression, and perhaps continuous naloxone infusion may be required, due to its shorter half life.

One of the most commonly used means of delivering opioid analgesics after major abdominal surgery is patient-controlled analgesia (PCA). Using this reliable, programmable delivery system, a variety of narcotic drugs including morphine, hydromorphone, meperidine, and fentanyl can be self-administered. For several variables, including demand (bolus) dose, lockout interval, and background infusion a PCA device can be programmed.(30)

Preemptive analgesia and thoracotomy

Some of the allodynia and hyperalgesia development mechanisms are well known. The concept of sensitization has resulted in increased efforts to control acute pain through a more or less total afferent blockade, with the aim of reducing post-thoracotomy pain development. Preventive