35
Principles of Perioperative Care of the Pediatric Surgical Patient
Randall S. Burd
Objectives
1. To implement a unified approach to the pediatric surgical patient and his/her family.
2. To outline a basic nutritional program for infants and children in the perioperative period.
3. To understand the principles of adjusting fluids in, of evaluating fluid loss in, and of adminis- tering blood products and medications to the pediatric surgical patient.
Case
You are asked to evaluate a 4-year-old boy for progressive abdominal distention and vomiting. He was well until 5 days ago, when he devel- oped anorexia and a low-grade fever. Because his parents felt that he had a “stomach flu,” they encouraged him to take liquids and gave him acetaminophen. Over the past day, he has had higher fevers at home and has developed increasing abdominal distention and vomiting. His parents estimate that he has lost several pounds during this recent illness. On examination, he has a temperature of 39°C, has a pulse rate of 110, is irritable, has sunken eyes, and has a distended tender abdomen. His white blood cell count is 19,000 with a left shift. A com- puted tomography (CT) scan of the abdomen is obtained that shows dilated loops of small bowel with inflammatory changes in the right lower quadrant, findings consistent with perforated appendicitis. An appendectomy is planned.
Introduction
Many medical students and surgical residents find their pediatric sur- gical rotation to be more difficult than their adult surgical rotations.
Because pediatric surgeons care for a wide range of children from
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premature infants weighing less than a kilogram to nearly adult teenagers, a single approach or formula that comfortably can be learned when caring for adult patients often cannot be used when caring for the pediatric surgical patient. In addition, infants and younger children cannot present their symptoms themselves and may not be able to cooperate with medical evaluation and treatment, making history taking and physical examination a frustrating experi- ences. While a single approach to perioperative management of pedi- atric surgical patients of all ages and with all diagnoses is impossible, we have found that a few general strategies can be used to simplify the care of the pediatric surgical patients (Table 35.1). This chapter presents these strategies, and gives guidelines on how these strategies can be applied in everyday practice.
Principle 1: Go Slow
A “slow-down” approach is most productive and time efficient when examining the pediatric surgical patient. A hurried approach to history taking and examination is upsetting to the child, prevent- ing accurate assessment and actually requiring additional time. The approach to pediatric surgical patients should be tailored to their ages and developmental stages. The first step in gaining the trust and the cooperation of the child during medical evaluation is to spend time in gaining the trust and cooperation of the parent. Parents understand- ably are anxious when their child is being evaluated for a possible sur- gical procedure, and even the smallest child easily can perceive this anxiety.
Infants and particularly toddlers are most difficult to examine for practitioners with no experience with children. A hurried approach particularly can be disruptive for this age group. Infants and toddlers often do not cooperate and do not understand the evaluation and the procedures that they are undergoing. Performing the physical exami- nation slowly and out of order usually is helpful. It is more useful to proceed first with the abdominal examination while one has the trust of the child, and to perform evaluations that more typically are upset- ting and may make the child cry, such as ear, nose, and throat exami- nations, at the end. It is useful to spend time having the child focus on a simple distraction, such as listening to the examiner’s whispered voice, holding a toy, or watching bubbles being blown. When examin- ing the child described in the case presented at the beginning of the chapter, using a calm voice, an unhurried approach, and a toy as a dis- traction may be useful.
Table 35.1. Principles for approaching the pedi- atric surgical patient.
Go slow Children grow
The child’s weight you should know
Although attempts at detailed explanations of anatomy and proce- dures usually are not productive, time should be spent giving older children and teenagers a simple age-specific explanation of planned evaluations and treatments in order to gain their trust and cooperation.
It also is useful to have children in these age groups participate with their parents in giving the medical history. Younger children are invited to provide additional information after their parents or caregivers have given the child’s medical history, while teenagers should be the initial source of medical information in order to respect their growing auton- omy. When possible, time should be spent with teenage patients in a second evaluation without a parent present, since important additional information may be obtained.
An additional aspect of a “slow-down” approach is to perform repeated examinations. If, during the initial encounter, the child is irri- table or crying, making evaluation difficult, the examination may be repeated when the child gains comfort with the environment or exam- iner. In the case presented, a more accurate abdominal examination may be obtained on repeat examination than on an initial examination.
Repeated evaluation particularly is useful in the emergency room eval- uation of trauma, since the need for multiple simultaneous evaluations and interventions may make it difficult to get an accurate assessment of key aspects of the physical examination. Repeating the evaluation more than once usually proves to be an efficient use of time.
Principle 2: Children Grow
Nutritional Assessment
Nutritional assessment is an essential feature of the care of the pedi- atric surgical patient in the perioperative period. In addition to the usual goal in adults of replenishing and maintaining nutritional status, children have an additional goal of requiring sufficient nutritional support to continue their normal growth and development. This aspect of care is important particularly in premature infants who may be hos- pitalized for several weeks or months after surgery during this impor- tant growth phase. The nutritional status of the hospitalized infant or child is evaluated on a daily basis to ensure that a plan is in place to meet the goals of replenishment, maintenance, or growth.
Although most children seen by the pediatric surgeon are healthy
and have adequate nutritional status, this observation should not
prevent initial nutritional assessment in any child. The first step is to
obtain an adequate nutritional history. The child’s medical history is
reviewed for acute illness (such as a viral illness associated with vom-
iting) or chronic illness (such as malignancy or metabolic disorders)
that may affect adversely the child’s baseline nutritional status. The
child’s surgical history also may be relevant if previous operations,
such as intestinal resection, have been performed that adversely may
affect gastrointestinal absorption and nutrition. The parent or caregiver
should be asked to provide information about the child’s dietary
history, food preferences, appetite, and recent weight changes.
Nutritional assessment continues with measurement of the child’s current weight and height. Head circumference also is included in the evaluation of infants and toddlers. Values are graphed on age-specific growth charts and compared to previous values whenever possible.
Useful guidelines in evaluating the weight of infants is that newborn infants usually lose 10% of their birth weight in the first week due to normal postnatal diuresis, and infants will double their birth weight by 5 months and triple their birth weight by 1 year. Weight is most useful for acute nutritional deficiency, while height and head circum- ference are more useful for evaluating chronic nutritional changes.
Although not required in most children, biochemical tests that can estimate nutritional status, such as albumin and transferrin levels, are useful when the initial history or examination suggests acute or chronic nutritional deficiency.
The Choice and Timing of Supplemental Nutrition
The decision whether or not to begin supplemental nutrition is made upon the child’s hospital admission and is reassessed daily. Supple- mental nutrition is not needed in most pediatric surgical patients, since initially most have adequate nutritional status and are hospitalized for only a few days. Even if a decision initially is made to defer using supplemental nutrition, it is essential to reevaluate this decision on a daily basis and to document the reasons for this decision, since acute malnutrition after surgery can affect the outcome adversely in even healthy children. When it is anticipated that the child will not be able to resume a normal diet within 5 days, additional supple- mentation should be initiated (see Algorithm 35.1). In the case pre- sented at the beginning of the chapter, the clinical examination suggests recent weight loss due to anorexia and vomiting. While the child can be expected to resume normal oral intake several days after surgery, the child’s weight on admission should be obtained and compared to his premorbid weight.
The route of administration of supplemental nutrition can be chosen using a simple algorithm (see Algorithm 35.1). An enteral route of nutrition generally is safest and least expensive. Evidence from adult and animal studies suggests that this route better preserves gut mucosal integrity and reduces the incidence of infectious and metabolic complications compared to using total parenteral nutrition. This route cannot be used when the gastrointestinal tract is not available because of recent abdominal surgery or in the presence of acute medical ill- nesses such as pancreatitis. When parenteral nutrition is begun, the reasons that require that choice should be reevaluated on a daily basis and a conversion to enteral nutrition should be started as soon as pos- sible. In the case presented, the child’s weight and oral intake should be followed carefully during hospitalization, and supplementation via an enteral or parenteral route should be initiated if a prolonged period of recovery is expected.
Estimating the nutritional requirements of infants and children
often is an intimidating task for those not experienced with children.
Although requirements differ markedly depending on age, a step-wise approach can be used in most cases to simplify this task. A good starting point for estimating the caloric needs of a child are the recommended daily allowances (RDA) that have been established for different age groups by the Food and Nutritional Board of the National Academy of Sciences (Table 35.2). When this table is not readily avail- able, the RDA can be approximated quickly by using this equation:
Estimated daily caloric requirements = [95 - (Age in years ¥ 3)]
kcal/kg/day. The major limitation of this method is that it tends to over- Estimated delay to
normal oral intake £5 days
• Maintenance IV fluids with dextrose
• Daily reassessment of need for nutritional support
Injured child
Estimated delay to normal oral intake >5 days
Intraabdominal injury Extraabdominal
injury
Able to use gastrointestinal
tract?
Yes Aspiration risk?
No
Yes Nasoduodenal tube
No Nasogastric tube
• Start TPN
• Reassess ability to use gastrointestinal tract daily Baseline nutritional assessment
• Review of medical / surgical history
• Review of dietary history
• Evaluation of preinjury weight and height / head circumference if <3 years old
Algorithm 35.1. Algorithm for evaluating the timing and route of administration of nutritional support in pediatric trauma patients. TPN, total parenteral nutrition. (Reprinted from Burd RS, Coats RD, Mitchell BS. Nutritional support of the pediatric trauma patient: a practical approach. Respir Care Clin North Am 2001;7(1):79–96. Copyright © 2001 Elsevier Inc. With permission from Elsevier.)
Table 35.2. Estimated caloric and protein require- ments in infants and children.
Energy requirements Protein Age (years) (kcal/kg/day) (g/kg/day)
0–0.5 108 2.0–2.5
0.5–1 98 2.0–2.5
1–3 102 1.5–2.0
4–6 90 1.5–2.0
7–10 70 1.5–2.0
Male 11–14 55 1.0–1.5
Female 11–14 47 1.0–1.5
Source: Adapted from Siberry GK, Iannone R. Nutrition. In:
The Harriet Lane Handbook, 15th ed. St. Louis, Mosby-Year Book, 1999. Reprinted from Burd RS, Coats RD, Mitchell BS.
Nutritional support of the pediatric trauma patient: a practi- cal approach. Respir Care Clin North Am 2001;7(1):79–96.
Copyright © 2001 Elsevier Inc. With permission from Elsevier.
estimate the requirements in overweight or edematous patients and to underestimate requirements in malnourished patients. Although it is most useful to use the ideal body weight of the child, these methods provide a convenient starting point that can be reassessed as nutritional supplementation is given.
Monitoring Nutritional Supplementation
Weight should be evaluated on a daily basis in all children, and length and head circumference should be evaluated on a periodic basis in infants. Because of the inaccuracy of individual weight measurements in small premature infants, it is useful to consider the average weight change over longer periods in these patients. In general, sufficient nutritional supplementation should be given to achieve a gain of 15 to 30 g/day in infants and about 0.5% of current weight per day in older children. When weight assessment is difficult for children receiving long-term nutritional support because of factors such as fluid shifts or the addition of bandages or casts, weekly mea- surement of prealbumin values is useful to evaluate the adequacy of nutritional support.
Designing a Nutritional Program
The individual components of total parenteral nutrition are estimated and modified according to the infant or child’s nutritional needs (see Algorithm 35.2). Adequate nitrogen usage usually can be achieved by providing 25 to 35 kcal of carbohydrate and lipid calories per gram of amino acids. Carbohydrates generally are given to provide 70% and lipids to provide 30% of nonprotein calories. The starting electrolyte composition of the formula is adjusted according to the child’s age (Table 35.3). As with all aspects of nutritional supplementation, these parameters are reassessed regularly, and appropriate modifications are made for the child’s current needs.
When an enteral route of nutrition is selected, direct modification of individual nutritional components usually is not needed, since most commonly used formulas have fixed and not modular components.
Nevertheless, it is important to evaluate the key components of any given formula to ensure that individual components, particularly protein content, are met adequately in children receiving long-term support. Similar to breast milk, most commercially available infant for- mulas (e.g., Similar or Enfamil) contain 20 kcal per ounce of formula.
Modified infant formulas suitable for premature infants that contain
24 kcal per ounce also are available. Breast milk almost always is pre-
ferred to formula and has been shown to afford a distinct outcome
advantage for critically ill pediatric surgical patients. When additional
calories are required, breast milk can be supplemented with commer-
cially available fortifiers or by the addition of separate components,
such as polycose or medium-chain fatty acid oils. Because the require-
ment for excess free water is unique to infants, formulas that provide
one calorie per milliliter such as Pediasure or Pediatric Vivonex,
usually are given to children older than 1 year. Because the solute
Estimating n utritional requir ements
Calories
Initial estimate Monitor ing • Use ideal body w eight • Initial estimate = [95 – (age ¥ 3)] kcal/kg/da y Fr ee water r equir ements • 100 mL/kg/day f or 1
st10 kg • 50 mL/kg/day f or 2
nd10 kg • 20 mL/kg/day f or r emaining wgt Pr otein g oal • 0–1 y ear s 2.5–3.0 g/kg/day = 10–12 kcal/kg/day • 2– 13 y ear s 2.0– 2.5 g/kg/day = 8– 10 kcal/kg/day • 13– 18 y ear s 1.5– 2.0 g/kg/day = 6– 8 kcal/kg/day
Fluids Pr oteins Carboh ydrates Fats Use “standar d” electr ol yte , trace element and vitamin f orm ulation (see text) Electr ol ytes/ trace elements/ vitamins
Fat g oal 10
3.4
Carboh ydrate g oal Fr ee w ater r equir ement
Pr ealbumin w eight change • Inf ants 15– 30 g/day • Child / teenag er 0.5% of weight/day T rigl yceride le vel
Urine glucose Blood glucose Pr ealbumin BUN 24-hour UUN Serum HCO
3–AL T , AST Total billirubin
Urine output: • 0– 1 y ear 2– 4 mL/kg/day • 1– 3 y ear s 1– 2 mL/kg/day • 4– 6 y ear s 1 mL/kg/day • 7– 10 y ear s 0.5 mL/kg/day • 11– 14 y ear s 0.3– 0.5 mL/kg/day Requir ed gr ams of glucose • Final glucose concentr ation (gr ams/deciliter) = Total kilocalor ies – (Gr ams of amino acid ¥ 4) – (Gr ams of glucose ¥ 3.4) • Gr ams of f at =
Desir ed % carboh ydr ates ¥ [(T otal kilocalor ies – (Gr ams of amino acid) ¥ 4)] • Gr ams of glucose = Algorithm 35.2. Estimating and monitoring components of nutritional support for the injur ed child. AL T , alanine aminotransferase; AST , aspartat e aminotransferase; BUN, blood ur ea nitr ogen; UUN, urinary ur ea nitr ogen. (Reprinted fr om Bur d RS, Coats RD, Mitchell BS. Nutriti onal support of the pediatric trauma patient: a practical appr oach. Respir Car e Clin North Am 2001;7(1):79–96. Copyright © 2001 Elsevier Inc. W ith permission fr om Elsevier .)
composition of these formulas may comprise up to about 30% of total volume, free water supplementation often is needed to achieve ade- quate fluid requirements and should be considered.
Principle 3: The Child’s Weight You Should Know
The Importance of Initial Weight Assessment
Virtually all medical interventions in children, including nutritional support, fluids, medications, and tubes, are adjusted according to patient size. For this reason, it is important to weigh every child as soon as possible at the start of any evaluation. When immediate medical intervention, such as an emergency trauma setting, precludes obtaining the patient’s weight, the child’s weight can be approximated quickly using the following formula: (Age in years ¥ 4) + 4 = Estimated weight in kilograms. Because the relative increase in weight observed in infants is greater than that observed in older children, adjustments based on weight changes may be needed on a daily basis in these patients.
Estimating Maintenance Fluid Rates
Maintenance fluids can be estimated rapidly using the 4-2-1 rule shown in Table 35.4. This method usually is easier to use than the 100- 50-20 rule, since intravenous fluids generally are ordered on an hourly and not on a daily basis. With the premature infant, the fluid rate is modified on a nearly hourly basis, since fluid shifts due to insensible losses and seemingly minor additions and deletions, such as catheter flushes and blood draws, may create important fluid shifts. Fluid
Table 35.3. Recommended daily electrolyte and trace element requirements in infants and children.
Component Daily requirement
Sodium 2–4 mEq/kg
Potassium 2–3 mEq/kg
Chloride 2–3 mEq/kg
Acetate 1–4 mEq/kg
Magnesium 0.25–0.5 mEq/kg
Calcium Neonate: 300–500 mg/kg
Infant: 100–200 mg/kg
Child/adolescent: 50–100 mg/kg Phosphorus Neonate: 1–1.5 mM/kg
Infant: 1.0 mM/kg
Child/adolescent: 0.5–1.0 mM/kg
Zinc 50 mg/kg
Copper 20 mg/kg
Chromium 0.2 mg/kg
Manganese 1 mg/kg
Source: Reprinted from Burd RS, Coats RD, Mitchell BS.
