Anesthesia and Perioperative Care

Respiratory System

Recent respiratory tract infections should be noted. Clear rhinorrhea without fever is not associated with increased anesthetic risk. Respiratory illnesses associated with fever, mucopurulent nasal discharge, productive cough, or lower respiratory symptoms (wheezing, rales) are associated with increased airway reactivity and anesthetic complications for up to 6 wk thereafter. There may also be increased risk of perioperative laryngospasm and bronchospasm, reduced mucociliary clearance, atelectasis, and hypoxemia. It is recommended that elective procedures requiring general anesthesia be postponed 4-6 wk in this setting.

Children with reactive airway disease require a thorough preanesthetic assessment. Acute, potentially fatal bronchospasm can occur during induction of anesthesia and endotracheal intubation for routine, minor surgery in children with asthma. Children at increased risk for anesthetic complications have experienced asthma exacerbations requiring (1) hospital admission within the previous year; (2) emergency department (ED) care within the last 6 mo; (3) previous intensive care unit (ICU) admission; or (4) previous parenteral systemic corticosteroids. Ideally, children should be free of wheezing for least several days before surgery, even if this necessitates increased controller medication administration (β-adrenergic agonist and corticosteroids). Active wheezing is an indication for delaying elective surgery. Chronic respiratory conditions such as bronchopulmonary dysplasia and cystic fibrosis are also associated with significant intraoperative risks. Every effort should be made to ensure that children with such disorders achieve optimal respiratory status before surgery.

Airway Evaluation

Induction of general anesthesia is associated with reduced spontaneous ventilation and airway reflexes. Prediction of difficult bag-mask ventilation and/or intubation before anesthesia is critical. Congenital anomalies associated with airway compromise include micrognathia, macroglossia, and thoracic anomalies ( Table 74.5 ). Conditions that impair mouth opening (e.g., temporomandibular joint disease) should also be noted. A history of wheezing or stridor may indicate postoperative airway complications and difficult intraoperative airway management. It is also essential to ask about a history of sleep-disordered breathing using the STBUR (snoring, trouble breathing, un-refreshed) index, which may be predictive of perioperative respiratory complications.

Cardiovascular System

Most anesthetic agents possess myocardial depressant properties. All patients should be screened for the presence of heart disease. Important cardiovascular considerations include history of congenital heart disease (CHD), cyanosis, arrhythmias, or cardiomyopathy. Room-air pulse oximetry should be performed as part of the preanesthetic evaluation. Accurate diagnosis of cardiac murmurs in neonates is essential. A history of cardiac dysrhythmias should be investigated because inhalational anesthetics may be arrhythmogenic. A pediatric cardiologist should evaluate children with known CHD undergoing surgery. Preoperative ancillary studies may include electrocardiogram (ECG), echocardiogram, or cardiac catheterization. Lesions associated with increased anesthetic risk include single-ventricle heart disease, fixed obstructive outflow tract lesions (aortic valve and pulmonary valve stenosis), and cardiomyopathy. Children with these conditions should be cared for by a cardiac anesthesia service . Antibiotic prophylaxis for the prevention of bacterial endocarditis may also be indicated, and the American Heart Association (AHA) guidelines should be followed.

Hematologic System

Evidence of coagulopathy should be sought. Easy bruising, familial bleeding disorders, and anticoagulant (e.g., aspirin, heparin, warfarin) use should be discussed. Preoperative adequacy of hemostatic function (e.g., platelet count, fibrinogen, prothrombin time, partial thromboplastin time) and correction of coagulopathic disorders may be indicated for complex procedures associated with significant risk of perioperative hemorrhage. In neonates, assurance of vitamin K prophylaxis and adequate coagulation status is critical before any major surgery. Although anemia may be well tolerated in healthy children, anesthesia and surgery increase oxygen consumption. Preoperative anemia should be corrected in the setting of reduced oxygen delivery or expected blood loss. In the patient with life threatening hemorrhage (trauma), massive transfusion protocols of 1 : 1:1 replacement of packed red blood cells:fresh-frozen plasma:platelets should be used.

Neurologic System

A history of neurologic and neuromuscular disorders should be sought. Preoperative developmental assessments may be helpful in interpreting age-dependent variation in the response to pain. Maintenance of appropriate perioperative anticonvulsant therapy is essential in children with seizure disorders because the seizure threshold may be lowered perioperatively. Children with obstructive hydrocephalus typically require ventriculoperitoneal (VP) shunt insertion to divert cerebrospinal fluid (CSF) and to prevent intracranial hypertension (ICH). Repeated shunt malfunction is common, and these children my present for shunt revision with signs of ICH (vomiting, altered mentation, sundowning). Similarly, shunt patency and function should be ensured preoperatively in children with VP shunts presenting for nonneurosurgical procedures.

Psychological Assessment

Surgery and painful medical procedures are psychologically traumatic events for children and families. Children who require anesthesia may experience fear and anxiety. They may also sense stressful signals from parents and caregivers. Many children undergoing surgery have new-onset negative behavioral changes postoperatively. These maladaptive behavioral responses may include enuresis, separation anxiety, temper tantrums, and nighttime crying, as well as fear of strangers, doctors, and hospitals. Sleep quality may be altered postoperatively, resulting in further behavioral compromise. Risk factors for postoperative behavioral changes include preoperative anxiety and emergence excitation. Need for recurrent procedures is another risk factor. Preoperative psychological preparation programs decrease the incidence of postoperative behavioral changes. Parental presence during induction (PPI) has not been shown to improve postoperative behavior (see later). Oral midazolam (0.5 mg/kg) may decrease negative behavioral changes after surgery. Midazolam has the benefit of providing rapid-onset anxiolysis and amnesia.

Genetic Evaluation

Children with genetic conditions may have syndrome-specific anesthetic considerations. For example, children with trisomy 21 may have cardiac anomalies, macroglossia, upper airway obstruction, and hypothyroidism (see Chapter 98.2 ). Atlantoaxial instability, common in trisomy 21, has been linked to cervical dislocation and spinal cord trauma with neck extension during intubation. Some anesthesiologists recommend extension and flexion lateral neck films to detect instability before surgery. For children with other known genetic disorders it is essential to review specific anesthetic considerations.

Preoperative Fasting

Preoperative fasting guidelines have been developed to reduce the incidence of aspiration of gastric contents during anesthesia. Aspiration may lead to laryngospasm, bronchospasm, and postoperative pneumonitis. Aspiration of gastric contents may be a potentially lethal complication in children with chronic lung disease or critical illness. Table 74.6 lists preoperative fasting guidelines (e.g., nothing by mouth, or nil per os [NPO] status). Clear, sweet liquids (e.g., Pedialyte, 5% dextrose in water [D5W]) facilitate gastric emptying, prevent hypoglycemia, and may be given up to 2 hr before anesthesia. Breast milk may be given to infants up to 4 hr before surgery. Solids should be avoided for 6-8 hr before surgery. Many conditions delay gastric emptying and may require prolonged periods of fasting.

Parental Presence During Induction of Anesthesia

Parents may expect to be with their child during the induction of anesthesia. Removing a fearful child from the comforting arms of a parent is stressful for the child, parents, and caregivers. When parental separation cannot be achieved comfortably with premedication and behavioral modification (patient education and desensitization to the operative environment), there may be a need to defer parent–child separation until general anesthesia is induced. Premedication with the oral benzodiazepine midazolam more frequently provides calm, smooth induction conditions than PPI without pharmacologic preparation. Although PPI in the hands of a confident, competent anesthesia practitioner may replace the need for preoperative medication, it does not reliably predict smooth induction. PPI has not been shown to decrease emergence delirium or postoperative behavioral changes, and it does not appear to be superior to premedication with oral midazolam.

Analgesia

Pediatric anesthesiologists are responsible for providing analgesia to children for procedures within operating room (OR) and non-OR settings ( Table 74.7 ). Multimodal techniques exist to provide pain relief during operative procedures for children of all ages, including critically ill infants. Effective analgesia is essential to blunt physiologic responses to painful stimuli (surgery) and modulate the deleterious physiologic and metabolic consequences. The response to painful and stressful stimuli may provoke systemic inflammatory response syndrome (SIRS) , which has been linked to increased catabolism, physiologic instability, and mortality (see Chapter 88 ).