Incidence, Severity, and Detection of Blood Pressure Perturbations after Abdominal Surgery: A Prospective Blinded Observational Study

WHAT WE ALREADY KNOW ABOUT THIS TOPICIntraoperative and postoperative hypotension are associated with myocardial and kidney injury and 30-day mortalityIntraoperative blood pressure is measured frequently, but blood pressure on surgical wards is usually measured only every 4 to 6 h WHAT THIS ARTICLE TELLS US THAT IS NEWIn adults recovering from abdominal surgery, continuous blood pressure recording with a noninvasive monitor revealed that both hypotension and hypertension were common, prolonged, and profoundMany of these events were not detected by the routine intermittent vital-sign assessments at 4-h intervals BACKGROUND:Intraoperative and postoperative hypotension are associated with myocardial and kidney injury and 30-day mortality. Intraoperative blood pressure is measured frequently, but blood pressure on surgical wards is usually measured only every 4 to 6 h, leaving long intervals during which hypotension and hypertension may be undetected. This study evaluated the incidence and severity of postoperative hypotension and hypertension in adults recovering from abdominal surgery and the extent to which serious perturbations were missed by routine vital-sign assessments. METHODS:Blood pressure was recorded at 1-min intervals during the initial 48 h in adults recovering from abdominal surgery using a continuous noninvasive monitor. Caregivers were blinded to these measurements and depended on routine vital-sign assessments. Hypotension and hypertension were characterized as time under and above various mean arterial pressure thresholds. RESULTS:Of 502 available patients, 312 patients with high-quality records were analyzed, with a median measurement time of 48 [interquartile range41, 48] postoperative hours. Nearly a quarter experienced an episode of mean arterial pressure of less than 70 mm Hg lasting at least 30 min (24%; 95% CI, 20%, 29%), and 18% had an episode of mean arterial pressure of less than 65 mm Hg lasting at least 15 min. Nearly half the patients who had mean arterial pressure of less than 65 mm Hg for at least 15 min (47%; 95% CI, 34%, 61%) were undetected by routine vital-sign assessments. Episodes of mean arterial pressure greater than 110 mm Hg lasting at least 30 min were observed in 42% (95% CI, 37%, 48%) of patients; 7% had mean arterial pressure greater than 130 mm Hg for at least 30 min, 96% of which were missed by routine assessments. Episodes of mean arterial pressure less than 65 mm Hg and mean arterial pressure greater than 11