An awareness of possible congenital anomalies or syndromes associated with abdominal and pelvic procedures is essential in a pediatric practice. Common congenital anomalies such as a Meckel’s diverticulum (an embryological remnant of the omphalomesenteric duct) may not significantly alter anesthetic management; however, it may completely alter the surgical procedure. A common abdominal procedure such as an appendectomy for acute appendicitis may be transformed into a Meckel’s diverticulum resection [1]. On occasion, the likeliness of associated syndrome or congenital anomalies will be raised by the age of presentation or clinical history. Intussusceptions are usually idiopathic; however, if recurrent or occurring in a child older than 3 years old, the incidence of associated cystic fibrosis, Burkitt lymphoma, or Peutz-Jeghers syndrome is increased [1]. At the other extreme, the abdominal pathologies will have significant associated anomalies which will have an impact on the anesthetic plan. Omphaloceles have been associated with chromosomal anomalies, bladder/cloacal exstrophy, neurological and cardiac defects, Beckwith-Wiedemann syndrome, and Down syndrome. These have significant anesthetic implications and they must be taken into consideration [2–4].

Trisomy 21 (i.e., Down syndrome) and Beckwith-Wiedemann syndrome are a reoccurring theme when it comes to abdominal and pelvic procedures. The range of abdominal and pelvic pathologies that have been associated with either or both is extensive and includes omphalocele, umbilical hernias, Hirschsprung disease, Wilms’ tumor, as well as others [3–6]. Specific airway considerations and possible associated congenital cardiac malformations with their physiological impact will add to the complexity of the anesthetic management in such patients. VACTERL (Vertebral, Anal, Cardiovascular, TransEsophageal, Renal, and Limb) anomalies are another possible association that the pediatric anesthesiologist should be aware of. A VACTERL association is more common with higher and more complex anorectal malformations; however, in a review by Rollins et al., a complete workup was felt to be warranted even with more benign lesion such as rectoperineal fistula [7].

Also important to consider is an understanding of the disease process as well as its possible complications or evolution. This may prompt the pediatric anesthesiologist to make additional preparation or plan for additional monitoring. Knowing that complex gastroschisis (commonly associated with bowel atresia) has an increased risk of morbidity and mortality [2], or that abdominal pathologies such as necrotizing enterocolitis, appendicitis, anorectal malformations, and intussusception have the potential to cause bowel necrosis and bowel perforation [1, 8], are good examples. Anticipating possible complications such as peritonitis and septic shock is very important and improves the chances of survival of the pediatric patient which could succumb to associated cardiovascular collapse, renal dysfunction, anemia, thrombocytopenia, and coagulopathy. Knowledge of the potential complications secondary to chemotherapy or radiotherapy when dealing with the pediatric oncologic abdominal or pelvic masses is also important. Myocardial damage resulting in cardiac dysrhythmias or acute cardiomyopathy, myelosuppression, hepatic failure, pulmonary fibrosis, or neuronal damages are some of the considerations inerrant to the anesthetic management of this population [6]. The mass or hormonal effects of neoplasm should also be considered. For example, Wilms’ tumors have been associated with systemic complications such as hypertension and acquired von Willebrand’s disease; in addition, vascular extension of this tumor may complicate the surgical procedure as well as anesthetic management due to possible pulmonary embolism and inferior vena cava or tricuspid valve obstruction from the mass itself [6].

Finally, electrolytes imbalance and volume status are common perioperative concerns with abdominal and pelvic procedures. Loss of gastrointestinal fluid due to excessive vomiting or diarrhea with abdominal pathologies such as appendicitis, intussusception, or pyloric stenosis may lead to abnormal electrolyte values. Certain tumor such as Wilms’ tumor may produce excessive amount of renin which can result in polydipsia and aldosterone-induced wasting of potassium [6]. This may also occur with pheochromocytoma and the secretion of excessive amount of catecholamines. Catecholamine secretions have also been associated with hyperglycemia which may require insulin therapy [9]. The electrolytes anomalies may also be related to genitourinary anomalies and renal dysfunction which is common in patient with anorectal malformations, gastroschisis, or Beckwith-Wiedemann syndrome [4, 10–12] Hypovolemia may result from various mechanisms: gastrointestinal bleeding third spacing, and large evaporative loss [3] are common in this patient population. Although early and aggressive fluid resuscitation (from 50 ml/kg up to 200 ml/kg) has been reported to improve outcome in sepsis [13], this may prove insufficient in pathologies such as a toxic megacolon syndrome and enteric bacteremia, where the combination of fluid as well as vasopressor support may be lifesaving measures [14].

Overall outcome and complication rate of abdominal and pelvic pathologies have greatly improved over the past 50 years. Gastroschisis, isolated omphalocele, and Wilms’ tumor are examples of pathologies that were associated with significant mortality rate which now have a survival rate of 90 % or more [10, 14]. The reasons leading to these remarkable improvements are probably multifactorial and multidisciplinary; total parenteral nutrition, neonatal and surgical care, oncology protocols, better diagnostic tools, identification of associated pathologies, and improved perioperative monitoring are some of the factors that may have contributed to these results. The practice of anesthesia has also evolved significantly over the past years, and patients have benefited from increased safety protocols and improved monitoring in the operating room.

A better understanding of the risk associated with a full stomach and the seriousness of aspiration pneumonitis has led to the adoption of strict rules regarding ingestion of fluid or solids during the perioperative period. Unfortunately, these rules should not be viewed as an assurance of an empty stomach since poor children compliance or delayed gastric emptying secondary to intestinal obstruction in pyloric stenosis or intussusception may interfere with normal gastric emptying. Direct assessment of gastric content with ultrasound has been looked at and may have future applications; however, it remains unproven at this time [16, 17]. Therefore, anesthesiologists still have to resort to the use of the rapid sequence induction (RSI) technique to minimize the risk of aspiration during the induction period. Gastric decompression with a nasogastric tube insertion prior to induction has been advocated to prevent or minimize the risk of aspiration [4, 18]. However, the classic RSI may represent a significant challenge in a pediatric population particularly when patients may be hypovolemic without IV access and may not want to cooperate for preoxygenation or an awake intubation [14, 16].

As was previously mentioned, Beckwith-Wiedemann and Down syndromes are frequent consideration with abdominal and pelvic procedures. Airway assessment prior to induction is important in order to evaluate the potential risk of a difficult intubation. Macroglossia is common with Beckwith-Wiedemann syndrome and may complicate airway management [4]. Down syndrome has a number of features which may also lead to difficulty in securing the airway: short neck, macroglossia, mandibular hypoplasia, cervical spine instability, subglottic stenosis, and poor cooperation due to possible mental retardation. In addition, Down syndrome patients may have associated congenital cardiac anomalies and are at risk for bradycardia with inhalational induction with sevoflurane [19, 20]. Combining all of those clinical features (acute abdomen, full stomach, difficult airway, cervical spine instability, congenital heart anomalies, bradycardia on induction, difficult or absent IV access) and managing these patients becomes a challenge even for the most experience pediatric anesthesiologist.

Certain pathologies such as pyloric stenosis, gastroschisis, necrotizing enterocolitis, or Hirschsprung disease are more prevalent during the neonatal period in patient who may be born prematurely. Appropriate ventilation becomes very important in these patients in order to avoid hypoxemia, oxygen toxicity or barotrauma. Tidal volume should not exceed 8 ml/kg, and the inspiratory oxygen concentration should be adjusted to maintain an oxygen saturation of 88–92 % [13]. Pulmonary hypoplasia should also be considered and may lead to prolonged mechanical ventilation and tracheostomy in this population [2, 21]. As an increased number of abdominal and pelvic procedures are being done laparoscopically, the reduced pulmonary compliance, increased airway pressure, and increased CO₂ load must also be considered during the operation [22]. In addition, given the relative short distance between the end of the endotracheal tube and the carina in small pediatric patients, the increased intra-abdominal pressure from gas insufflation during laparoscopy, can lead to the cephalad displacement of the carina [14] resulting in possible endobronchial intubation orsevere bronchospasm. Adequacy of ventilation should also be reassessed postoperatively since the procedure itself may have impacts on the ventilatory parameters. For example, after primary closure of a gastroschisis, the resultant increase in intra-abdominal pressure could negatively affect postoperative ventilation.