Monitoring patients with sleep-disordered breathing on the general care floor present challenges for healthcare workers.
By Franklin A. Holman
Patients with sleep-disordered breathing present challenges for the medical professionals overseeing their care on the general care floor. Fortunately, there are monitoring strategies to reduce delayed diagnosis of respiratory decompensation and technology that can aid in diagnostic accuracy.
Frank J. Overdyk, MSEE, MD, adjunct professor of anesthesiology at Medical University of South Carolina, shares these strategies and explains how technology can aid in detecting respiratory changes.
RT: Can you explain the monitoring deficiencies that currently exist on the general care floor that lead to unrecognized respiratory decompensation?
Overdyk: Currently, the monitoring standard we have on a general care floor relies on spot checks of vital signs and nursing assessment. The biggest risk to patients is that these vital signs and assessments can occur as infrequently as every 4 hours on the first postoperative night when they are likely to develop respiratory complications from residual anesthesia, narcotic pain medicines, and sedatives. Even patients who have not had surgery but are receiving these medications require more frequent monitoring than every 4 hours, especially at night when the assessment of the patient is complicated, because critical respiratory depression is not easily differentiated from deep sleep unless the patient is awakened and properly assessed.
RT: What postoperative complications exist in patients with sleep-disordered breathing?
Overdyk: The complications are primarily respiratory in nature and related to their increased risk of losing a patent airway as a result of pain medicines and other drugs that blunt their ability to arouse to hypercarbia and hypoxemia. This may result in cardiac ischemia, arrhythmias, and hemodynamic collapse resulting in “Code Blue.”
RT: What preoperative screening techniques exist for sleep-disordered breathing patients, and of these, do we know which screens work best?
Overdyk: Some of the screening tests are questionnaires; they are subjective. Some of the tests are more objective and have to do with clinical cephalometry and invasive techniques. As for screening, the work pressure in the perioperative environment is such that the screening needs to be quickly done and have a low false-negative rate. The most sensitive studies for diagnosing OSA are quite time and procedure intensive, and involve x-rays.
However, questionnaires such as the STOP-BANG have been shown to be sufficiently sensitive as a quick initial screening test to add value in triaging patients at high risk for respiratory complications.
RT: In your opinion, what monitoring strategies will reduce delayed diagnosis of respiratory decompensation on the general care floor?
Overdyk: There are a couple of immediate strategies that are available. The first is to implement continuous monitoring versus interval monitoring (or spot check) monitoring. The second relies on telemetry with a trained observer to be able to raise the alarm when there are patterns consistent with a patient who has respiratory decompensation as opposed to placing this burden of interpreting the data on the bedside nurse. Most importantly, this construct will minimize alarm fatigue that is inherent in current threshold triggered monitors.
RT: What technology exists that can help reduce false-positive alarms and also aid in diagnostic accuracy?
Overdyk: On the general care floor, we have a problem with alarm fatigue, mostly because these patients have different levels of consciousness (LOC) and are quite different from the typical patient in the operating room and ICU. Their LOC can vary from natural sleep or oversedation to talking, ambulating, and taking oral medicines and food. In those settings, the monitors that we traditionally use to detect respiratory changes in the operating room are less specific, have frequent false positives, and cause alarm fatigue.
The strategy to eliminate alarm fatigue is multifactorial. Most important, monitor alarms must divest from simple threshold alarms. They must detect trends and patterns that we have identified as having greater specificity for a patient who may suffer respiratory decompensation. Multiple physiologic inputs as opposed to a single one also will add specificity, such as interpreting heart rate, oxygen saturation, respiratory rate, and chest movement before sounding an alarm. If you have capnography data, look at the end tidal CO2, the respiratory rate, and the other data. You can bring hemodynamic measurements, blood pressure, and pulse pressure into that algorithm as well.
There are monitoring platforms that integrate a number of physiologic channels and can make smarter diagnostic inferences. They can’t make diagnoses, but they can raise an alarm with a higher degree of sensitivity and specificity (which creates alarm fatigue) than a traditional, single threshold triggered alarm.
RT: Overall, what key points should health care professionals understand about monitoring the patient with sleep-disordered breathing on the general care floor?
Overdyk: I hope they are aware that the reason “failure to rescue” remains a top cause of morbidity and mortality in our hospitals is that we are failing to recognize respiratory decompensation early enough in our patients (efferent loop of the MET/RRT team). Subsequently, the afferent loop of the MET/RRT (code team) is unable to improve outcomes predictably. Continuous monitoring of any respiratory variable is essential. Continuous SpO2 may be adequate so long as the patient is not receiving supplemental oxygen, in which case a continuous ventilatory monitoring indicative of airflow (eg, ETCO2) is required. Impedance-based ventilatory monitoring relying on chest excursion may not be effective in obstructive etiologies of respiratory decompensation.
Last, professionals who are monitoring OSA patients should aim for strategies that have built-in redundancy, much like those that the aviation industry has implemented in order to make flying extremely safe. A continuous monitor in combination with more frequent checks of neurologic status, especially at night, is essential in eliminating preventable deaths and anoxic brain injury in patients found dead in bed.
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