No abstract

being repositioned to 45 head-up. An electrocardiogram was recorded continuously (Spacelabs Lifecard CF monitor, Spacelabs Healthcare). Heart rate recovery quantified cardiac vagal function; low frequency-domain power spectrum analysis quantified baroreflex function (Kubios HRV Premium v.3.1, Finland). Postoperative morbidity 3 days after surgery was recorded using the Post-Operative Morbidity Survey (POMS). Repeated-measures analysis of variance tested for differences over time between patients with/without morbidity. Overall, 117/170 (69%) patients developed postoperative morbidity. Delayed heart rate recovery was observed in patients who developed POMS (P¼0.04, Fig. 10). Patients who developed morbidity also had reduced mean low frequency-domain measures (5.34 ms 2 ; 95% confidence interval [CI], 5.12e5.57 ms 2), compared with patients who remained free of postoperative morbidity (5.8 ms À2 ; 95% CI, 5.43e6.16 ms 2 ; P¼0.03). This reproducible, standardised orthostatic challenge may be a useful clinical tool to examine the link between autonomic function and postoperative morbidity.