Incidence, severity and detection of blood pressure and heart rate perturbations in postoperative ward patients after noncardiac surgery

Continuous vital sign monitoring of patients recovering from surgery on general wards: a narrative review

Most postoperative deaths occur on general wards, often linked to complications associated with untreated changes in vital signs. Monitoring in these units is typically intermittent checks each shift or maximally every 4-6 h, which misses prolonged periods of subtle changes in physiology that can herald a critical downstream event. Continuous monitoring of vital signs is therefore intuitively necessary for patient safety. The past five decades have seen monitoring systems evolve rapidly, and today entirely wireless, wearable, and portable continuous surveillance of vital signs is possible on general wards. Introduction of this technology has the potential to modify both the sensing (afferent) and response (efferent) limbs of monitoring, and will allow earlier detection of vital signs perturbations. But this comes with challenges, including but not limited to issues with connectivity, data handling, alarm fatigue, information overload, and lack of meaningful clinical interventions. Evidence from before and after studies and retrospective propensity-matched data suggests that continuous ward monitoring decreases the risk of intensive care unit (ICU) admissions, rapid response calls, and in some instances, mortality. This review summarises the history of general ward monitoring and describes future directions, including opportunities to implement these devices using artificial intelligence, pattern detection, and user-friendly interfaces. Pragmatic, well designed and appropriately powered trials, and real-world implementation data are necessary to make continuous monitoring standard practice at every hospital bed.

Continuous vital sign monitoring on surgical wards: The COSMOS pilot

STUDY OBJECTIVES

Alerts for vital sign abnormalities seek to identify meaningful patient instability while limiting alarm fatigue. Optimal vital sign alarm settings for postoperative patients remain unknown, as is whether alerts lead to effective clinical responses reducing vital sign disturbances. We conducted a 2-phase pilot study to identify thresholds and delays and test the hypothesis that alerts from continuous monitoring reduce the duration of vital sign abnormalities.

DESIGN

Two-phase pilot.

PATIENTS

250 adults having major non-cardiac surgery.

SETTING

Surgical wards.

INTERVENTION

All patients had routine vital sign monitoring by nurses at 4-h intervals. We initially continuously recorded clinician-blinded saturation, heart rate, and respiratory rate in 100 patients. In the second phase, we randomized 150 patients to blinded versus unblinded continuous vital sign monitoring. In unblinded patients, nurses were verbally alerted to abnormal vital signs.

MEASUREMENTS

In the first phase, we modeled expected alarm counts using 6082 h of continuous oxygen saturation, heart rate, and respiratory rate data. Thresholds and delays targeting ∼3 alarms per patient per day were selected for phase two. Primary analysis assessed the effect of unblinded monitoring across a 5-component primary composite of cumulative durations of vital sign abnormalities. Secondary outcomes included fraction of alerts deemed meaningful by nurses and number of clinical interventions.

RESULTS

In phase one, we identified alarm settings that yielded an average of 2.3 alerts per patient per day. In phase two, the average relative effect ratio of geometric duration means for vital signs exceeding thresholds was 0.75 [95 % CI: 0.51, 1.1], P = 0.17. Sixty alarms (82 %) were deemed useful in unblinded patients, leading to 60 % more interventions in unblinded patients.

CONCLUSIONS

We were able to select continuous saturation, heart rate, and respiratory rate thresholds that generated about 2 alerts per patient per day, nearly all of which were considered useful by nurses. Unblinded monitoring and nursing alerts led to interventions (mostly increasing oxygen delivery) that non-significantly reduced vital sign abnormalities by 25 %.

CLINICALTRIALS

gov registration: NCT05280574.

Perioperative Patients With Hemodynamic Instability: Consensus Recommendations of the Anesthesia Patient Safety Foundation

In November of 2022, the Anesthesia Patient Safety Foundation held a Consensus Conference on Hemodynamic Instability with invited experts. The objective was to review the science and use expert consensus to produce best practice recommendations to address the issue of perioperative hemodynamic instability. After expert presentations, a modified Delphi process using discussions, voting, and feedback resulted in 17 recommendations regarding advancing the perioperative care of the patient at risk of, or with, hemodynamic instability. There were 17 high-level recommendations. These recommendations related to the following 7 domains: Current Knowledge (5 statements); Preventing Hemodynamic Instability-Related Harm During All Phases of Care (4 statements); Data-Driven Quality Improvement (3 statements); Informing Patients (2 statements); The Importance of Technology (1 statement); Launch a National Campaign (1 statement); and Advancing the Science (1 statement). A summary of the recommendations is presented in Table 1 .

Impact of continuous and wireless monitoring of vital signs on clinical outcomes: a propensity-matched observational study of surgical ward patients

BACKGROUND

Continuous and wireless vital sign monitoring is superior to intermittent monitoring in detecting vital sign abnormalities; however, the impact on clinical outcomes has not been established.

METHODS

We performed a propensity-matched analysis of data describing patients admitted to general surgical wards between January 2018 and December 2019 at a single, tertiary medical centre in the USA. The primary outcome was a composite of in-hospital mortality or ICU transfer during hospitalisation. Secondary outcomes were the odds of individual components of the primary outcome, and heart failure, myocardial infarction, acute kidney injury, and rapid response team activations. Data are presented as odds ratios (ORs) with 95% confidence intervals (CIs) and n (%).

RESULTS

We initially screened a population of 34,636 patients (mean age 58.3 (Range 18-101) yr, 16,456 (47.5%) women. After propensity matching, intermittent monitoring (n=12 345) was associated with increased risk of a composite of mortality or ICU admission (OR 3.42, 95% CI 3.19-3.67; P<0.001), and heart failure (OR 1.48, 95% CI 1.21-1.81; P<0.001), myocardial infarction (OR 3.87, 95% CI 2.71-5.71; P<0.001), and acute kidney injury (OR 1.32, 95% CI 1.09-1.57; P<0.001) compared with continuous wireless monitoring (n=7955). The odds of rapid response team intervention were similar in both groups (OR 0.86, 95% CI 0.79-1.06; P=0.726).

CONCLUSIONS

Patients who received continuous ward monitoring were less likely to die or be admitted to ICU than those who received intermittent monitoring. These findings should be confirmed in prospective randomised trials.