LAUSR

BACKGROUND Intra-operative tachycardia during noncardiac surgery has been associated with adverse postoperative outcomes. However, harm thresholds for tachycardia have not been uniformly defined. The definition of intra-operative tachycardia that best correlates with adverse postoperative outcomes remains unclear. OBJECTIVE We aimed to identify the definition of intra-operative tachycardia during noncardiac surgery that is associated with the best predictive ability for adverse postoperative outcomes. DESIGN A single-centre retrospective cohort analysis. SETTING Secondary care hospital, Afula, Israel. PATIENTS AND METHODS Adults who underwent elective or nonelective noncardiac surgery during 2015 to 2019. Five intra-operative heart rate (HR) cut-off values and durations were applied with penalised logistic regression modelling for the outcome measures. MAIN OUTCOME MEASURES The primary outcome was all-cause 30-day mortality; the secondary outcome was myocardial ischaemia or infarction (MI) within 30 days after noncardiac surgery. RESULTS The derivation and validation datasets included 6490 and 4553 patients, respectively. Altogether, all-cause 30-day mortality and MI rates averaged 2.1% and 3.2%, respectively. Only two definitions of intra-operative tachycardia were significantly associated with the outcome measures: HR ≥ 100 bpm for ≥ 30 min and HR ≥ 120 bpm for ≥ 5 min. The C-statistics of the base models without tachycardia exposure for all-cause 30-day mortality and MI were 0.75 (95% confidence interval, CI, 0.74 to 0.78) and 0.73 (95% CI, 0.72 to 0.76), respectively. The addition of intra-operative tachycardia exposure to the base models significantly improved their predictive performance. The highest area under the curve (AUC) was achieved when tachycardia was defined as an intra-operative HR ≥ 100 bpm for at least 30 min: AUC 0.81 (95% CI, 0.80 to 0.84) and AUC 0.80 (95% CI, 0.79 to 0.82) for all-cause 30-day mortality and MI, respectively. CONCLUSION Intra-operative tachycardia, defined as an intra-operative HR ≥ 100 bpm for at least 30 min, was associated with the highest predictive power for adverse postoperative outcomes.