Continuous Versus Intermittent Ward Monitoring

The investigators will randomize adults having major non-cardiac inpatient surgery to blinded versus unblinded continuous vital sign monitoring (saturation, ventilation, and heart rate) and hourly intermittent blood pressure recordings. The investigators will use a wearable, untethered, and battery-powered monitor (Masimo Radius VSM, Masimo, Irvine, CA) that continuously records saturation, ventilation, and heart rate, and intermittently records blood pressure.

Our primary outcome will be areas-exceeding-thresholds for desaturation (\<85%),3 bradypnea (\<5 breaths/min), tachypnea (\>25 breaths/min), tachycardia (heart rate \>130 beats/min), bradycardia (heart rate \<35 beats/min),4 mean arterial pressure (MAP) \<65 mmHg, and MAP \>145 mmHg. These exposure thresholds represent a balance between events that are clinically meaningful and excessive alarms that will discourage clinician participation. In unblinded patients, clinician alerts will be activated at these thresholds.

Postoperative cardiovascular mortality remains common,1 and a third occurs during the initial hospitalization. Deterioration occurs over many hours but is usually unrecognized because vital signs are evaluated a 4-6-hour intervals,2 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 vital sign monitoring (saturation, ventilation, and heart rate) and hourly intermittent blood pressure recordings. The investigators will use a wearable, untethered, and battery-powered monitor (Masimo Radius VSM, Masimo, Irvine, CA) that continuously records saturation, ventilation, and heart rate, and intermittently records blood pressure.

Our primary outcome will be areas-exceeding-thresholds for desaturation (\<85%),3 bradypnea (\<5 breaths/min), tachypnea (\>25 breaths/min), tachycardia (heart rate \>130 beats/min), bradycardia (heart rate \<35 beats/min),4 mean arterial pressure (MAP) \<65 mmHg, and MAP \>145 mmHg. These exposure thresholds represent a balance between events that are clinically meaningful and excessive alarms that will discourage clinician participation. 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, bradycardia, and hypotension. On an exploratory basis, as a pilot for a future major multi-center outcome trial, the investigators will evaluate a composite of major complications within 30 days after non-cardiac inpatient surgery including unplanned intubation, myocardial injury after non-cardiac surgery (MINS), non-fatal cardiac arrest, stroke, sepsis, in-hospital mortality, and hospital readmission.

Our 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.

Eligibility Criteria:
Inclusion Criteria:

1. Are admitted to one of the wards equipped with the Masimo Radius VSM solution;
2. Are ≥18 years old;
3. Are designated American Society of Anesthesiologists physical status 1-4;
4. Had major noncardiac surgery lasting at least 1.5 hours;
5. Are expected to remain hospitalized at least two postoperative nights;
6. Had general anesthesia with or without neuraxial anesthesia.

Exclusion Criteria:

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