Incidence and risk factors for preincision hypotension in a noncardiac pediatric surgical population

Background: Routine monitoring of blood pressure is an essential part of perioperative care in adults and children. It is however not known whether intraoperative hypotension (IOH) is clinically important in the ‘healthy’ pediatric patient. This may be partly due to the lack of data on the incidence and consequences of IOH in this group of patients. We utilized the Brain Trauma Foundation definition of hypotension to describe the incidence of preincision hypotension (PIH) in a large pediatric noncardiac surgical population and identified risk factors for the occurrence PIH.

Methods: We examined the electronic perioperative records of all children aged 1–17 years undergoing general anesthesia for noncardiac surgeries between January 2005 and June 2007 in our institution. Frequency and factors associated with PIH were computed. Binary logistic regression with forward step-wise algorithm was used to examine factors associated with PIH.

Results: There were 22 263 children of whom 57.6% were males. Most (94.9%) cases were elective, American Society of Anesthesiologists (ASA) I–II (79.5%) procedures. Inhalational induction was predominantly used in this cohort (67%) although 33% of patients had propofol either as a sole induction agent or as part of a ‘co-induction’ regime. Single or multiple episodes of PIH occurred in 35.8% of patients. PIH was more common in patients with ASA ≥ III (P < 0.001); those with preoperative hypotension (P < 0.001); and following intravenous induction (P < 0.001) as well as propofol co-induction (P < 0.001). On multivariate analysis the following were significant predictors of PIH: baseline hypotension, propofol co-induction, age, ASA ≥ III, and long preincision period.

Conclusion: Preincision hypotension is common in the pediatric surgical population undergoing general anesthesia. Factors independently predictive of PIH included high ASA status, pre-existing hypotension, propofol co-induction prolonged preincision period and adolescent age group. The importance of blood pressure monitoring, prompt recognition of hypotension and use of appropriate intervention is emphasized.