LITHUANIAN UNIVERSITY OF HEALTH SCIENCES

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LITHUANIAN UNIVERSITY OF HEALTH SCIENCES

Faculty of Medicine

Disaster medicine department

Administration of CPAP mask for patients with acute respiratory

failure in prehospital calls by EMS teams

Thesis author:

Jonathan Tabakman

Kaunas, 2020 thesis supervisor:

Professor Dinas Vaitkaitis, MD

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1. Summary

Author’s name and surname: Jonathan Tabakman

Research title: Administration of CPAP mask for patients with acute respiratory failure in prehospital calls by EMS teams – systematic literature review

Introduction : CPAP is an integral part of the hospital treatment in ARF and provides beneficial effects on respiratory and cardiac functions. This noninvasive medical therapy maintains positive airway pressure during spontaneous ventilation throughout the whole respiratory cycle, reducing dyspnea and the work of breathing.(7) In this study I am going to systematically review the studies that provide information about CPAP mechanism, outcome and benefits in prehospital treatment of acute respiratory failure due to pulmonary edema and COPD.

Research Aim: Literature review of prehospital CPAP treatment in patients with acute respiratory failure.

Objectives: 1. Analyze the effectiveness of CPAP administration in acute respiratory failure in prehospital environment by EMS teams.

2. Evaluate the safety of the device – CPAP.

Methodology: In this study, data was conducted by PRISMA (preferred reporting items for systematic review) as guideline for the basis of research methodology. Total of 23 articles in English language were selected

Research results: The most common used CPAP mask is the Boussignac CPAP. The Boussignac CPAP system is a simple, safe, cheap and lightweight (10 g) plastic cylinder that is directly connected to a disposable face mask and been shown to be effective for ACPE in the emergency department and in prehospital care.(11). According to published medical case studies, CPAP involvement in prehospital care has shown positive influence on further patient’s condition improving saturation, respiratory rate, blood pressure and blood chemistry (2,10,18–20) as well as reducing need of endotracheal intubation (1,5,10,18,19).

Conclusions: This method is used worldwide as part of EMS guidelines and protocols as it is safe and easy to use, it provides fast results and suitable to most of the patients. It can be

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4 declare that the CPAP is effective, as it improves vital signs such as heart rate, respiratory rate, saturation and blood pressure, moreover it decreases intubation rate in prehospital care.

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2. CONFLICT OF INTEREST

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3. CLEARANCE ISSUED BY THE ETHICS COMMITTEE

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4. ABBREVIATIONS

• CPAP – continues positive airway pressure • CPE – cardiopulmonary edema

• COPD – chronic obstructive pulmonary disease • EMS – emergency medical service

• NIV – noninvasive ventilation • ETI – endo tracheal intubation • CHF – congestive heart failure

• PEEP – positive end expiratory pressure • ICU – intensive care unit

• MICU – mobile intensive care unit • ACPE – acute cardiopulmonary edema • ARF – acute respiratory failure

• RR – respiratory rate • HR – heart rate

• BPM – beats per minute

• SaO2 – oxygen saturation in blood serum • SBP – systolic blood pressure

• EMT – emergency medical technician • GCS – Glasgow comma scale

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5. Terms

• Acute respiratory failure – rapid onset clinical view of a patient who cant held his normal physiological breathing control and is defined in immediate life risk.

• Emergency medical service – any organizations which support pre-hospital medical and emergency care by ambulances

• Endotracheal intubation – an invasive medical procedure by which a tube is inserted through the mouth down into the trachea (the large airway from the mouth to the lungs)

• Glasgow comma scale – is a neurological scale which aims to give a reliable and objective way of recording the state of a person’s consciousness for initial as well as subsequent assessment

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6. INTRODUCTION

Dyspnea is a frequent symptom among patients in the prehospital setting. Common causes of non-traumatic dyspnea are CHF, pneumonia, COPD and asthma.(1) In the USA, approximately one million patients per year are treated by paramedics for acute exacerbation of CHF and COPD.(2) Acute CHF exacerbation and acute COPD exacerbation may occur from a variety of processes that rapidity deteriorates to this generalized cardiopulmonary disorder and RF (3). In North America, Europe, Australia and some countries in the middle East the classical treatment of controlling acute pulmonary edema and COPD attack include supplemental oxygen, vasodilators, small doses of IV opiods, loop diuretics, bronchodilators and steroids (for COPD). If conventional pharmaceutical treatment is not effective or the patient is associated with respiratory depression tracheal intubation and mechanical

ventilation are often needed, which, by themselves are associated with a worse prognosis.(3) While prehospital therapy with oxygen, nitrates, morphine, and furosemide is often effective, patients with progressive respiratory failure generally require ventilatory support. Administering continuous positive airway pressure (CPAP) by face mask has been shown to reduce the need for endotracheal intubation (ETI) and mechanical ventilation in hospitalized patients with severe cardiogenic pulmonary edema (4) and; On the recent decade, more and more EMS systems wide world adopted the approach not to ventilate patient due to poor prognosis and potential complications during invasive ventilation – ET intubation.

Continuous positive airway pressure (CPAP) is a form of noninvasive ventilation NIV(5); Which is now the recommended first line method for ventilator support in selected patients with ARF.(6) NIV is generally delivered by using combination of PSV plus PEEP. Unlike NIV, CPAP does not deliver ventilation per se because it does not assist inspiration.(6) CPAP is an integral part of the hospital treatment in ARF and provides beneficial effects on

respiratory and cardiac functions. This non invasive medical therapy maintains positive airway pressure during spontaneous ventilation through out the whole respiratory cycle, reducing dyspnea and the work of breathing.(7)

The CPAP mask has been designed to be easy to use by EMS teams, convenient and safe for the patients and has beneficial physiological outcomes, such as gas exchange

improvement, reducing the rate of ET intubation and decreasing the length of stay in ICU and not delaying the ER treatment. Furthermore CPAP results in faster clinical improvement and

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10 can reduce the requirement for invasive ventilation that increases the risk of complications including nosocomial infections and tracheal injury which prolong ICU stay and hospital stay(5)

Since the late 1980’s researches and studies have recently explored the application of using CPAP in the prehospital setting for EMS teams, especially for paramedics and there is some evidence to support a benefit in regard the morbidity, mortality, safety and availability for usage in prehospital conditions. The aim of this study is to systematically review the most recent studies that show the benefits and safeties of CPAP in prehospital settings for patients with ARF due to several cardiological and respiratory emergencies.

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7. AIM AND OBJECTIVES OF THE THESIS

Aim of the thesis: Literature review of prehospital CPAP treatment in patients with acute respiratory failure.

Objectives:

1. Analyze the effectiveness of CPAP administration in acute respiratory failure in prehospital environment by EMS teams.

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8. RESEARCH METHODOLOGY AND METHODS

Search strategies:

The main goal was to select related articles about CPAP usage in prehospital field through following information sources:

PubMed database https://www.ncbi.nlm.nih.gov/pubmed/ 1. Google Scholar -https://scholar.google.com/ 2.

UpToDate online database

-https://www.uptodate.com/contents/search 3.

Total of 23 articles in English language were selected and 3 out of them were marked as most relevant for final conclusions. In this study, data was conducted by PRISMA (preferred reporting items for systematic review) as guideline for the basis of research methodology. A detailed chart (figure 1) is showing all process.

Selected keywords for search:

CPAP, Dyspnea, Prehospital, Paramedic, Ambulance, Noninvasive, Emergency, ARF, CHF, COPD, Ventilation, EMS

Selected phrases for search:

▪ “CPAP application in prehospital”

▪ “CPAP for patients with acute respiratory failure” ▪ “noninvasive ventilation in ARF”

▪ “Prehospital treatment for patients with CHF and COPD” ▪ “CPAP usage in ambulance”

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13 Eligibility criteria:

▪ Publications between 2011 up to 2017

▪ CPAP usage in prehospital settings for patients with CPAP treatment indications ▪ Meta-analysis, evidence based studies and systematic reviews based on previous data

bases from North America and Western Europe published in English language

Exclusion criteria :

▪ Publication year 2010 and earlier ▪ CPAP treatment in hospital care ▪ Pediatrics cases

▪ Non-EMS teams

chart number 1. PRISMA flow chart which demonstrating how articles were included or excluded during data collection

5100 studies were identified through data base search

2450 were left after duplicates and exclusion criteria was applied

130 studies were screened due to their relevancy

32 full-text articles were left and assessed for eligibility •12 articles were excluded due to irrelavent date of publish

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9. RESULTS AND DISCUSSION

9.1 Historical and physiological review of CPAP

The history of CPAP begins in the XX century, when Bunnel applied a noninvasive positive airway pressure treatment for the first time to maintain lung expansion during thoracic surgery with the help of face mask. Studies conducted by Barach et al. over the 1930 showed that CPAP, delivered through face mask, could be useful in treatment of CPE and other forms of respiratory failure.(8) As well, CPAP therapy for sleep apnea was initiated in the 1980s. (9) Since then NIP was used for ventilatory assistance and treatment of CHF, COPD, asthma. After it’s success in ARF treatment CPAP had encouraged studies in acute care settings in 1990s. In the CPAP study period paramedics were instructed to administer CPAP immediately as an additional treatment to the standard care.(10)

The most common used CPAP mask is the Boussignac CPAP. The Boussignac CPAP system is a simple, safe, cheap and lightweight (10 g) plastic cylinder that is directly connected to a disposable face mask and been shown to be effective for ACPE in the emergency department and in prehospital care.(11) Positive airway pressure is established using this system by means of a 'virtual valve', where the gas originating from a source of fresh gas is led into a specially shaped plastic cylinder and is swirled around. The vortex creates increasing pressure, dependent on the flow but without direct linear relation. All the time, the system is constantly open, so the patient does not need to overcome additional mechanical obstacles while inhaling and exhaling. The generated excess pressure can be read via a manometer using a bypass method. The gas source is oxygen. Depending on the flow, the resulting oxygen content varies between 70% and 100%(12).

The system’s high advance is being lightweight due to no need for ventilators or machines with main connection or heavy tubing. An oxygen flow of 15 l/min which can be generated from simple oxygen tank of 2-3 Liters volume, can generate a pressure of 5 cm H2O (11).

The idea of outflowing oxygen with positive pressure is a mechanic pushing fluids to the base of the lung and free as much as higher percentage of free space in the lungs.

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Figure 1. The physiological mechanics of the CPAP (11)

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16 Figure 3. Parts carried by EMS teams for applying CPAP mask (12)

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9.2 Indications And Contraindications For Applying Cpap Mask

Although all reviewed articles and studies were done in different countries and different continents, All EMS teams were instructed almost as the same way to use CPAP mask for same pathophysiological respiratory emergencies which were mostly acute CPE and acute on chronic COPD exacerbations. Selected articles which were covering MICU EMS teams in New-Jersey state, New-York state, Denmark, France, Germany, UK, Canada showed that the indications and contraindications for placing CPAP mask were almost the same with some exclusions regarding minimal age of use. All in all, in north America, Europe and Australia the minimum age was 18 and above (1,6–8,10,12–15) except one study which was based on protocols of EMS team in San-Diego, USA, referred for patients who were 15 and above as adults and not as pediatrics (although the youngest patient was 62 years old) (15).

All EMS teams without exceptions were guided to use CPAP mask based on the following criteria (16) or when most of the following clinical presentations were appeared on patients:

• ARF with >25 breaths per minute • Tachycardia > 100 BPM HR

• Hypertension or Systolic BP > 120 mm/Hg

• Labored breathing resulting in inability to complete the alphabet • SAT02% <90% in R/O

• Patients who were in orthopnea position

• Diffused crackles which were heard during lungs auscultation • Accessory muscle use

• Alert consciousness with ability to cooperate with EMS teams • Acute situation of CPE or acute on chronic COPD exacerbation In all cases, in the CPAP study period, paramedics were instructed to administer CPAP immediately as an additional treatment to the standard care (10) when patient was presenting the clinical signs as mentioned.

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18 When one or more of the following terms was presented, CPAP usage was

absolutely contraindicated in all EMS teams (1,2,14,15,17,4–8,10,12,13) without exceptions: • Weight below 40 kg

• Sever trauma / abnormality of face

• Patients who were not alert (state of conscious) • Vomiting and nausea

• Bleeding in oral cavity • Respiratory rate <12

• Patient who mantel can’t tolerate CPAP

• sever bradypnea which required immediate airway management • lack of oxygen supply

• suspected pneumothorax • hypotension (systolic BP <90) • suspected stroke involvement

figure 4. The protocol of Canadian ambulance service in Toronto – indications and contraindications for CPAP (14)

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9.3 Benefits And Outcome

According to published medical case studies ,CPAP involvement in prehospital care has shown positive influence on further patient’s condition improving saturation, respiratory rate, blood pressure and blood chemistry (2,10,18–20) as well as reducing need of

endotracheal intubation(1,5,10,18,19). No less importantly, it does not require long medical training preparing prehospital care specialist to use CPAP device in their practice (16). “Emergency physicians in the Kaiserslautern EMS were trained in the application of the system in a two-hour training session. A total of 57 patients, 35 with ACPE and 22 with COPD ,received CPAP therapy, None of the therapy failures occurred with emergency physicians who had little or no CPAP experience.” (12)

A study which has been made in 2014 in Delaware USA, has shown significant improving of patients who were treated with CPAP by EMT in point of care. EMT’s arrived before ALS team and under specific criteria were instructed to install CPAP mask as a first line treatment in ARF. For all 74 patients (100.0%), CPAP was correctly indicated and applied; CPAP was appropriately monitored for almost all patients (98.6%; 71/72), with two patients having unknown CPAP monitoring status. Respiratory status also was appropriately managed in almost all patients (98.6%; 72/73), with one patient having unknown respiratory management status. The BLS CPAP administration statistically significantly reduced the proportion of patients with spO2 values <92%, a RR>24 breaths per minute, and who were cyanotic (Table 2). Overall, there was an 84% reduction in the proportion of patients with poor spO2 values, a 55% reduction in those experiencing poor RRs, and a 58% reduction in cyanosis. Finally, differences before and after BLS CPAP administration by BLS for three continuous metrics, GCS, HR, and spO2, were examined. All three metrics displayed

improvement after CPAP administration. Comparing pre-CPAP and post-CPAP values, there was a statistically significant decrease in HR (16). With successful results demonstrating the effectiveness of a basic affordable device on a respiratory disorder and its associated

outcomes, it is plausible that further training and application should be indicated in all paramedic/ EMS training in the future. (9) furthermore, the final conclusion of a study regarding the safety of the device was firm and clear - Continuous positive airway pressure can be safely used by BLS providers with appropriate training, QA processes, and medical direction oversight. Patients treated with CPAP by BLS providers were observed to have

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20 improvements in their clinical status and vital signs. Further studies may be needed to

determine longer term effects on patients and EMS systems from the use of CPAP administered by BLS providers. (5,16)

As per intubation rate, a retro- perspective analysis of EMS teams in new-jersey, USA was testing the rate of intubations of patients who were treated with or without CPAP. Analysis of the data revealed that the diagnostic categories of RF, respiratory failure, RD, and respiratory distress were not equally distributed in the patients. This is likely due to the assignment of diagnostic categories from the pre-set International Classification of Diseases (ICD) coding system. Given these assigned diagnoses, there is likely to be overlap noted across the similar categories. However, this skewed distribution was accounted for through the use of propensity scores. In 330 male patients, 87 (26.4%) were intubated, but in 455 female patients,105 (23.1%) were intubated (P=0.3131). In 396 patients with CHF, 52 (13.1%) were intubated; in 136 COPD patients, 8 (5.9%) were intubated; in 43 patients with RD, 6 (14 %) were intubated; in 3 ARD patients none was intubated; and in 207 patients with RF 126 (60.9%) were intubated.

There was a significant difference between diagnoses (P<0.0001). In 215 EMS patients treated with CPAP before hospitalization, 28 (13.0%) were intubated after admission. But in 570 EMS patients treated with CPAP, 164 (28.8%) were intubated after admission to the ED.

There was a significant difference in intubation rates between the EMS patients treated with CPAP before hospitalization and those who treated with no CPAP(P<0.0001). (9)

figure 4. shows how the metanalysis and comparing intubated VS non-intubated for patients who were applied with or without CPAP (9)

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21 However, despite improving patients physiological valuables, CPAP influence on reducing mortality rate is shown to be not significant ,what is concluded in Canadian and Australian studies (2,5). Taking into consideration the mechanism of CPAP treatment there is risk of hyperoxia and oxidative stress as complications, patients’ anxiety and claustrophobia caused by device “ The untoward effects of hyperoxia and oxidative stress have led to more restrictive prehospital oxygen administration protocols. Hyperoxia has been shown to decrease coronary blood flow and induce free-radical formation with resultant oxidative stress”. (20)

A clinical study which was made in France with marked question of differences between IV therapy with or without CPAP shows no difference between patients who were treated with CPAP comparing to patients who were treated with simple oxygen supply and aggressive medical-drug therapy. In the prehospital setting, in spite of its potential advantages for patients in ACPE, CPAP may not be preferred to a strict optimal treatment including low-dose morphine, furosemide, oxygen, and high-low-dose boluses of isosorbide dinitrate

unrestricted according to clinical response. (16) however, need to mention that except France, all EMS teams which were observed and studied didn’t include emergency physician and teams were only paramedics – who were limited and streaked by doses and drugs not like doctors who were “free hand” to used any drug without any limitations.

Following graphs are demonstrating the differences of vital signs before and after CPAP was applied in critical-care patients.

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22 Graph 1. The dynamics of respiratory rate before and after CPAP (10,14,15,20)

Graph 2. The dynamics of heart rate before and after CPAP (15,16,20) Thomas Luiz

et-al/2016

Vibe Maria Laden Nielsen et-al/2016

Steve A. Aguilar

et-al/2013 Bryan E. et-al/ 2011

RR before 26.9 28.5 32 34.5 RR after 18.9 26 28 27.9 26.9 28.5 32 34.5 18.9 26 28 27.9 0 5 10 15 20 25 30 35

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Respiratory rate as a difference before and after

CPAP apply

111 110.2 115.7 106 106.8 105.1 98 100 102 104 106 108 110 112 114 116 118

S. A. Aguilar et al/2011 B. Andersen et al/ 2012 N. Sahu et al/2017

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Heart rate as a difference before and after CPAP

apply

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23 Graph 3. The dynamics of oxygen saturation before and after CPAP (10,12,16,20)

T. Luiz et al / 2016 V. Nielsen et al 2016 E. Anderson et al/2012 N. Sahu et al/2017

SaO2 before 81.6 91.5 81 88 SaO2 after 94.8 94 94.2 96.9 81.6 91.5 81 88 94.8 ₉₄ _94.2 96.9 70 75 80 85 90 95 100

SaO2 as difference before and after CPAP apply

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10. Conclusion

1. The CPAP treatment worldwide usage was evaluated based on the found relevant literature. The CPAP has been administrated in respiratory emergencies which require rapid and effective results as breathing support for patients with respiratory failure. This method is used worldwide as part of EMS guidelines and protocols as it is safe and easy to use, it provides fast results and suitable to most of the patients.

2. The CPAP benefits were reviewed in relevant articles and summed up to evaluate the effectiveness of the method. The CPAP is effective, as it improves vital signs such as heart rate, respiratory rate, saturation and blood pressure, moreover it decreases intubation rate in prehospital care.

3. CPAP can be used even by BLS ambulances (which cant provide any medicament or invasive procedures) and increase the rate of survival of critical care patients until arriving to emergency departments without delaying the treatment.

4. The mechanism of CPAP is simple and does not require long-time medical stuff training, what decreases the chances of wrong mask applying. The number of

contraindications is low, what decreases the potential risks. Moreover, if wrong decision was made, the mask can be removed fast and easy.

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11. REFERENCES

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