Association between post anaesthesia care unit hypotension and ward hypotension after non-cardiac, non-obstetric surgery: a single-centre retrospective cohort study

BACKGROUND: Hypotension on the surgical ward is associated with harm. We assessed the effect of post anaesthesia care unit (PACU) hypotension on the odds of ward hypotension and secondary outcomes including medical emergency team (MET) calls, intensive care unit (ICU) admission, acute kidney injury (AKI), delirium, hospital and 30-day mortality and hospital length of stay (LOS) in patients after non-cardiac, non-obstetric surgery. METHODS: We conducted a retrospective cohort study of patients having non-cardiac, non-obstetric surgery over one year. The primary outcome was ward hypotension (systolic blood pressure < 90 mmHg). We estimated adjusted odds ratios using a mixed effects logistic regression model, adjusted for age, sex, emergency surgical status, surgical duration, American Society of Anesthesiologists (ASA) physical status, number of antihypertensive medications and use of analgesia in PACU. RESULTS: We included 11,634 procedures in 10,258 unique patients. PACU hypotension was observed after 547 (4.7%), ward hypotension after 517 (4.4%), and 165 (30%) of PACU hypotension cases had ward hypotension. Patients with PACU hypotension showed increased odds of ward hypotension (aOR 16.35, 95% CI: 10.32–25.92), MET calls (aOR = 2.66 [95% CI: 1.71–4.14]), ICU admission (aOR = 5.59 [95% CI: 3.03–10.32]), AKI (aOR = 2.21 ]95% CI: 1.43–3.40]), delirium (aOR = 6.28 [95% CI: 2.83–13.95]), hospital mortality (aOR = 3.21 [95% CI: 1.77–5.81]), 30-day mortality (aOR = 2.00 [95% CI: 1.26–3.18]), and longer hospital LOS (adjusted median difference = 0.83 [95% CI: 0.49–1.16]). CONCLUSION: Hypotension in PACU was associated with significantly higher odds of ward hypotension and clinically important outcomes.