Continuously monitored vital signs for detection of myocardial injury in high-risk patients - An observational study

Abstract

Background: Patients are at risk of myocardial injury after major non-cardiac surgery and during acute illness. Myocardial injury is associated with mortality, but often asymptomatic and currently detected through intermittent cardiac biomarker screening. This delays diagnosis, where vital signs deviations may serve as a proxy for early signs of myocardial injury. This study aimed to assess the association between continuous monitored vital sign deviations and subsequent myocardial injury following major abdominal cancer surgery and during acute exacerbation of chronic obstructive pulmonary disease.

Methods: Patients undergoing major abdominal cancer surgery or admitted with acute exacerbation of chronic obstructive pulmonary disease had daily troponin measurements. Continuous wireless monitoring of several vital signs was performed for up to 96 h after admission or surgery. The primary exposure was cumulative duration of peripheral oxygen saturation (SpO2 ) below 85% in the 24 h before the primary outcome of myocardial injury, defined as a new onset ischaemic troponin elevation assessed daily. If no myocardial injury occurred, the primary exposure was based on the first 24 h of measurement.

Results: A total of 662 patients were continuously monitored and 113 (17%) had a myocardial injury. Cumulative duration of SpO2 < 85% was significantly associated with myocardial injury (mean difference 14.2 min [95% confidence interval -4.7 to 33.1 min]; p = .005). Durations of hypoxaemia (SpO2 < 88% and SpO2 < 80%), tachycardia (HR > 110 bpm and HR > 130 bpm) and tachypnoea (RR > 24 min-1 and RR > 30 min-1 ) were also significantly associated with myocardial injury (p < .04, for all).

Conclusion: Duration of severely low SpO2 detected by continuous wireless monitoring is significantly associated with myocardial injury in high-risk patients admitted to hospital wards. The effect of early detection and interventions should be assessed next.

Keywords: acute exacerbation of chronic obstructive pulmonary disease; continuously monitoring; hypoxaemia; myocardial injury; noncardiac surgery; tachycardia; tachypnoea; vital signs.

Conflict of interest statement

The WARD founders have created a start‐up company, WARD247 ApS, with the aim of pursuing the regulatory and commercial activities of the WARD‐project. WARD247 ApS has obtained license agreement for any WARD‐project software and patents. One patent has been filed: “Wireless Assessment of Respiratory and circulatory Distress (WARD) – Clinical Support System (CSS) – an automated clinical support system to improve patient safety and outcomes.” None of the above entities influenced the study design, conduct, analysis, or reporting.

© 2022 The Authors. Acta Anaesthesiologica Scandinavica published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.

Figures

FIGURE 1

Study period overview. *If elevated at day 3. AECOPD, acute exacerbation of chronic obstructive pulmonary disease; hsTnT, high‐sensitive cardiac troponin T; PACU, post‐anaesthesia care unit

FIGURE 2

Title: Flow diagram of patient inclusion. aSurgical patients only; bAECOPD patients only. ICD, Implantable Cardioverter Defibrillator; MMSE, Mini‐Mental State Examination

FIGURE 3

Frequency of patients with myocardial injury and median peak hsTnT, both stratified by number of different micro events. Micro events were defined as dichotomized deviations specified as 5 or more consecutive minutes of the following: hypoxaemia, SpO2 < 85%; bradycardia, HR < 40 bpm; bradypnoea, RR < 11 min−1 and tachypnoea, RR >24 min−1. Micro events of hypotension were defined as 60 consecutive minutes of SBP < 90 mmHg and hypertension SBP > 180 mmHg and tachycardia HR > 130 bpm for ≥30 min. SpO2, Peripheral oxygen saturation; hsTnT, high‐sensitive cardiac troponin T