Monitoring and intervention strategies for patients with respiratory compromise are much more efficient and effective if patients are first categorized by the type of respiratory condition they have. This contrasts with the mentality of monitoring by putting all respiratory patients into the same bucket.
This assessment was made following a workshop organized by the National Association for the Medical Direction of Respiratory Care, which assembled multi-institutional experts from pulmonary care, critical care, anesthesiology and other fields. In a summary presented in Respiratory Care (2017;62:497-512), the experts advocated recognition of patients who are in respiratory compromise and establishing six categories of acutely ill respiratory patients.
“The manuscript was inspired by personal observations about patients who ended up in the intensive care unit who seemed to have had a disorder that could have been reversible or treatable had there been some warning before they eventually developed respiratory failure,” said lead author Timothy Morris, MD, president of the Respiratory Compromise Institute (RCI), in Arlington, Va. “In speaking with my colleagues at the University of California, San Diego [UCSD], and in professional networks, not having some warning in many of these patients seemed to be a very common theme. There was also a consensus that there were plenty of steps we could have taken, if only we had gotten to these patients a little bit earlier.” Dr. Morris is also professor of medicine in the Division of Pulmonary Critical Care and Sleep Medicine at UCSD.
The article does not specify any one particular method of monitoring, because patients who have different types of respiratory disorders “require very different types of monitoring strategy,” Dr. Morris said. “A one-size-fits-all strategy is probably a mistake.”
For example, a patient with emphysema is “going to suffer respiratory failure in an entirely different pathway than someone with sleep apnea and an opioid overdose or with a pulmonary embolism or pneumonia,” Dr. Morris said.
Six Categories, Six Monitoring Practices
The six categories of respiratory compromise listed in the article are:
- impaired control of breathing,
- impaired airway protection,
- parenchymal lung disease,
- increased airway resistance,
- hydrostaticpulmonary edema, and
- right ventricular failure.
For impaired control of breathing, continuous monitoring of arterial partial pressure of carbon dioxide (pCO2) is useful. “Although end-tidal capnometry has some advantages, it does not account for dead space,” Dr. Morris said. Pulse oximetry for levels of consciousness is also recommended for continuous monitoring. “All of these strategies should be matched up periodically with arterial blood gas (ABG) measurement,” Dr. Morris said.
For impaired airway protection, probably the best continuous monitoring is pulse oximetry. “You want to determine if the patient has aspirated or is at great risk for aspiration,” Dr. Morris said.
In addition, as with impaired control of breathing, the level of consciousness should be evaluated. Speech therapy tests on a routine basis are also helpful to access the patient’s ability to chew and any delays between lip stimulation and swallowing.
For parenchymal lung disease, continuous monitoring is more straightforward for breathing frequency and pulse oximetry, along with considering the need for supplemental oxygen. Dr. Morris said the patient’s mental status and ABG measurements should also be assessed.
For increased airway resistance, continuous monitoring is largely predicated on the patient’s ability to breathe on his or her own.
“Some of this is indirect, like heart rate, but evaluation of breathing frequency can be helpful, as can oximetry and capnometry to a lesser extent,” Dr. Morris said. “However, because of the dead space issue, transcutaneous pCO2 may end up being a better measurement than exhaled end-tidal CO2 in this particular subset of patients.”
Continuous monitoring for hydrostatic pulmonary edema is similar to parenchymal lung disease. “But for frequent evaluation, there are lots of different ways to estimate extravascular lung water, ranging from simply evaluating a chest X-ray to CT scans,” Dr. Morris said. “ABG should also be performed periodically to ensure that oxygenation does not fall below the anticipated level.”
Right ventricular failure, by contrast, “is a little tricky because of the rapidity at which patients can decompensate,” Dr. Morris said. “For continuous monitoring, it is really more about hemodynamics than it is about necessarily gas exchange.” Therefore, blood pressure, heart rate, respiratory frequency, EKG changes, and to a minor extent pulse oximetry are beneficial. “These things should also probably be plotted over time as you are looking for a trajectory pattern,” Dr. Morris said.
Periodic echocardiography and serologic tests to assess cardiac strain can also be helpful in patients with right ventricular failure.
“Unfortunately, strategies for these six indications are not used very often,” Dr. Morris said. “I am hopeful that this is one of those circumstances where we outline some relatively noncontroversial interventions that simply have not been used because the systems have not been put in place to use them yet.”
He said the major hurdle in implementing such monitoring and interventions is manpower. “You need to identify when patients are in a state of respiratory compromise and who are at a substantial risk of worsening. The role for anesthesiologists is to make an intervention earlier than they typically do on patients, and institute the type of intelligent monitoring and intervention decisions that they usually reserve for patients who are much sicker.”