Continuous Versus Intermittent Ward Monitoring

Postoperative cardiovascular mortality remains common, and two-thirds occurs during the initial hospitalization. Deterioration typically occurs over hours but is usually unrecognized because vital signs are evaluated a 4-6-hour intervals, just as they were a half-century ago when patient acuity was much lower. Recognition of even subtle changes in basic vital signs may allow clinicians to detect cardiopulmonary deterioration well before serious adverse events occur. Consequent clinical interventions may in turn prevent complications, or at least moderate their severity. The investigators therefore propose a single-center randomized trial of continuous ward monitoring.

The investigators will randomize adults having major non-cardiac inpatient surgery to blinded versus unblinded continuous saturation, ventilation, and heart rate monitoring. Postoperative cardiovascular mortality remains common, and a third occurs during the initial hospitalization. Deterioration occurs over many hours but is usually unrecognized because vital signs are evaluated 4-6-hour intervals, just as they were a half-century ago when patient acuity was much lower. Recognition of even subtle changes in basic vital signs may allow clinicians to detect cardiopulmonary deterioration well before serious adverse events occur. Consequent clinical interventions may in turn prevent complications, or at least moderate their severity. The investigators therefore propose a single-center randomized trial of continuous ward monitoring.

The Investigators will randomize adults having major non-cardiac inpatient surgery to blinded versus unblinded continuous postoperative vital sign monitoring (saturation, ventilation, and heart rate). The investigators will use a wearable, untethered, and battery-powered sensor (Masimo Rad-97 with Radius PPG Tetherless Pulse oximetry system, Masimo, Irvine, CA) that wirelessly connects to a work station and continuously records saturation, ventilation, and pulse rate.

The primary outcome will be areas-exceeding-thresholds for desaturation (<85%), bradypnea (<7 breaths/min), tachypnea (>30 breaths/min), tachycardia (heart rate >130 beats/min), and bradycardia (heart rate <45 beats/min). These exposure thresholds represent a balance between events that are clinically meaningful and excessive alarms that will discourage clinician participation. The investigators expect about 2 alerts per patient per day with these thresholds, with most being considered informative or actionable by nurses. In unblinded patients, clinician alerts will be activated at these thresholds.

Secondarily, the investigators will evaluate a composite of clinical interventions for desaturation, bradypnea, tachypnea, tachycardia, and bradycardia. On an exploratory basis, as a pilot for a future major multi-center outcome trial, The investigators will evaluate a composite of major complications including naloxone administration, rapid-response team activation, unplanned ICU transfer, and mortality within 7 postoperative days.

The innovative long-term goal is to reduce in-hospital postoperative cardiovascular and pulmonary mortality. Specifically, The investigators expect to show that continuous rather than intermittent postoperative vital sign monitoring identifies unstable patients which will allow clinicians to intervene and prevent serious complications and death - thus promoting longer and healthier lives.

Inclusion criteria

• Are admitted to one of the wards equipped with the Masimo Radius PPG and Rad-97 monitors;
• Are ≥18 years old;
• Are designated American Society of Anesthesiologists physical status 1-4;
• Had major noncardiac surgery lasting at least 1.5 hours;
• Are expected to remain hospitalized at least two postoperative nights;
• Had general anesthesia with or without neuraxial anesthesia.

Exclusion criteria

• Have language, vision, or hearing impairments that may compromise continuous monitoring;
• Are designated Do Not Resuscitate, hospice, or receiving end of life care;
• Have previously participated in the study.