Non-invasive continuous haemodynamic monitoring and response to intervention in haemodynamically unstable patients during rapid response team review

Introduction: During rapid response team (RRT) management of haemodynamic instability (HI), continuous non-invasive haemodynamic monitoring may provide supplemental physiological information. Objectives: To continuously and non-invasively obtain the cardiac index (CI) and mean arterial pressure (MAP) in patients with HI at baseline and during RRT management using the ClearSight (TM) device. Methods: We performed a prospective observational study in adult patients managed by the RRT for tachycardia or hypotension or both. We assessed changes from baseline in heart rate (HR), MAP, CI, stroke volume index (SVI) and systemic vascular resistance index (SVRI) (i) at 5-minutely intervals up to 20 min, and (ii) over the entire 20-min period. We analysed patients by RRT trigger (tachycardia/hypotension) and intervention (fluid bolus therapy [FBTJ/ no FBT). Results: We successfully recorded the CI in 47 of 50 (94%) patients. RRT reviews triggered by hypotension ratherthan tachycardia had a lower baseline HR (-45.4 bpm, p= <0.0001), MAP (-16.1 mmHg, p= 0.0007) and CI (1.0L/min/m(2), p = 0.0025). Compared to baseline, in the tachycardia group, there was a small increase in MAP overall and at the 15-20 min time-block from 83.2 mmHg to 87.1 mmHg (+3.9 mmHg, p= 0.0066) and 85.5 mmHg (+2.3 mmHg, p = 0.0061), respectively. In those who received FBT, there was a statistically significant increase in MAP overall and at the 15-20 min time-block compared to baseline, from 70.1 mmHg to 73.5 mmHg (+3.4 mmHg, p= 0.0036) and 74.3 mmHg (+4.2 mmHg, p = 0.0037), respectively. However, there were no statistically significant changes in mean HR, CI, SVI, or SVRI when comparing baseline to the entire 20-min period or 5-min time-blocks within any group. Conclusions: Continuous non-invasive measurement of haemodynamics during RRT management for HI was possible for 20 min. Patients with hypotension ratherthan tachycardia had lower baseline HR, MAP and CI values. There was a statistically significant but small increase in MAP at the 1520 min time-block and overall, for both the tachycardia and FBT groups.