Blood pressure measurements during intraoperative pediatric scoliosis surgery

Background: Intraoperative hypotension is frequently encountered during surgery and it can be associated with adverse outcomes. Blood pressure monitoring is critical during surgery, but there are no universally agreed upon standards for interpreting values of hypotension and no consensus regarding interventions. Material and Methods: We performed a retrospective chart review of pediatric patients who underwent idiopathic scoliosis surgery by a single surgeon. We used the arterial line for all measures. Intraoperative hypotension was defined as 20% decrease of the baseline systolic blood pressure (SBP), 30% decrease of baseline SBP, or mean arterial pressure less than 60 mmHg. Use of vasopressor agents was also recorded and correlated with blood pressure definitions. Results: Seventy idiopathic scoliosis patients were retrospectively evaluated. There was a significant correlation between the three measures of hypotension. Sixty percent of the patients received vasopressors. There was a significant correlation between a drop of mean arterial pressure to less than 60 mmHg and the use of the ephedrine. We did not find any changes on neuromonitoring measures during the case and there were no intraoperative or one-month postoperative complications. Conclusions: Blood pressure is only one of the measures anesthesiologists look to for good perfusion during surgery. Pediatric anesthesiologists and orthopedics agree in trying tight blood pressure control during surgery to decrease blood loss, but what the exact definition of that blood pressure number is, is still unclear. We propose that using mean arterial pressure less than 60 mmHg is perhaps a better definition. We provide recommendations for future studies.