Recovery Characteristics in Neonates Following General Anesthesia: A Retrospective Chart Review

Abstract

Introduction Preterm babies increasingly survive the neonatal period as a result of advanced care practices. Accordingly, anesthesiologists are likely to encounter these patients with greater frequency. Ex-premature infants and term neonates are known to have an increased risk of post-operative apneas following surgery and anaesthesia. Methods Following approval from the Institutional Review Board, we performed a retrospective chart review of neonates 0-28 days of age who underwent general anaesthesia procedures over two years. Data collected included age days, sex, weight, gestational age, American Society of Anaesthesiologists (ASA) physical status, type of anaesthetic (general/regional/spinal), airway management, surgical procedure, intraoperative adverse events, duration of anaesthesia, medications administered, post-operative recovery location, the occurrence of apneic events, medical co-morbidities, duration of post anaesthesia care unit (PACU) admission, a requirement for neonatal intensive care unit (NICU) admission, and duration of hospital admission. Results A total of 239 charts were reviewed from January 1, 2015, to December 31, 2016. Ninety-five cases were excluded for required postoperative mechanical ventilation. For the remaining 144 cases, the mean age was 12.8 days, 65% male, 35% female, mean gestational age 38.6 weeks, mean post-menstrual age 40.5 weeks, mean ASA status 3.5, and mean weight 3.46 kg. Post-operative apnea was observed in two neonates (1.4%). Risk factors for postoperative apnea included lower gestational age at birth (median 37.5 vs. 39.1 weeks, p=0.26), lower post-menstrual age (median 38.5 vs. 41.0 weeks, p=0.18), and lower weight (median 2.8 vs. 3.5kg, p=0.27), respectively. ASA classification, preoperative anaemia, and known pathology were all significant risk factors for apnea (p<0.05). Significant factors from the bivariate analysis were preoperative anaemia, known pathology, age, duration of anaesthesia, weight, intraoperative fentanyl, and amount of neuromuscular blocker. Age and preoperative anaemia were significant predictors for recovery location. The odds of going to PACU vs NICU/PICU for post-operative recovery were 7.4 times greater for every two weeks greater age (95% CI=(2.80-19.31), p<0.001). Conclusion This study corroborates previous findings of predictive risk factors for post-anaesthesia apnea in preterm and term neonates. Previously reported risk factors, including low gestational/post-menstrual age, lower weight, and intraoperative narcotic use, were likely contributors to one of the apneic events in our study. A larger sample size is warranted to confirm a valid predictive model. Standardized universal guidelines would be useful in eliminating local variation in PACU monitoring and discharge criteria in this vulnerable age group.

Keywords: general anesthesia; neonatal; post operative monitoring; postoperative apnea.