Essential Capnography


As a major, regional teaching hospital in Greater Los Angeles, White Memorial Medical Center is a 353-bed institution playing an important role training physicians, nurses and other health professionals. I have been a Respiratory Care Practitioner (RCP) since 1983. In my early years of practice, pulse oximetry was considered the save all system to use to monitor patients to prevent any hypoxic events from occurring. While pulse oximetry is indeed very good and has become a universally acceptable process for monitoring for patients, it has, in my opinion, given room for error in how one may think a patient’s true condition is.

For the RCP, we know that pulse oximetry should only be used to indicate a patient’s oxygenation status and that it is only accurate to the point of how well perfused the site is where the probe is placed.

Opioids & Conscious Sedation
Clinicians often debate the pros and cons of using pulse oximetry versus capnography for monitoring patients receiving opioids.

Those patients who are on patient controlled analgesia (PCA) pumps are able to receive a continuous low dose of pain medications and they also have the ability to self-administer a prescribed dosage at a set time frame to help manage their pain. In some patients this has caused too much medication to be delivered and the patient becomes so sedated that it adversely suppresses their breathing. This can be life threatening if not caught early so the medication dosage can be stopped and/or reduced.

This same concern comes with all patients who receive conscious sedation for procedures. Every possible system that is available should be employed in order to protect patients from harm because they are always at risk of receiving more sedation medication than they can handle.

As an example, if a patient is on a nasal cannula at 2 lpm (estimated FiO2 28%,) , and has a normal respiratory rate, the pulse oximetry should read greater than 90% in most patients. Take the same patient and reduce their respiratory rate due to sedation or impending respiratory failure, the same liter flow now has a chance to build up the concentration of oxygen in the anatomical dead space thus increasing the FiO2 allowing the saturation to climb higher giving the caregiver a false sense that the patient is doing well. Once the patient has decreased their respiratory rate to a critical point and the saturations drops due to poor ventilation the window of opportunity has passed and the chances of the patient coding has increased dramatically. If the original condition of the patient was precarious to begin with, the chances for recovery may have gone to a point of no return.

SEE ALSO: Culture of Safety Includes Capnography

First, Do No Harm
With ETCO2 in conjunction with pulse oximetry the caregiver will know quickly that a condition for concern for the patients safety has been met and action needs to be taken immediately, thus reducing any harmful effects. Being able to respond in a timely manner to prevent adverse situations will reduce adverse events, the potential for litigation, reduce unwanted admissions into the hospital, reduce length of stay and so on; which all greatly impact the bottom line. The reputation of the facility, physicians, and staff will be preserved, but more importantly than anything else the avoidance of harm to patients is the ultimate goal.

Because of these shortcomings with monitoring with pulse oximetry, at our facility we have instituted mandatory capnography with each PCA device placed. This specific model will automatically pause the infusion of pain medicine if an alarm limit is reached. The pump cannot be reactivated until the patient has been assessed and the nurse or RCP has evaluated the patient to make sure they are out of harm’s way. The nurses and RCP’s have stated that this system works. With capnography used with PCA’s, it has and will continue to decrease the number of rapid response calls for this group of patients.

Monitoring equipment will not replace the need for human intervention. There will and should always remain nurses and RCP’s to monitor patients. If done the correct way, the combination of equipment and staff vigilance with patient monitoring will keep patients safe.

Addressing Alarm Fatigue
Alarms! They wake or disturb the patient and they sound all day long on the patient floors. This is the most often heard complaint by staff and patients, so much so that the Joint Commission has made reducing alarm fatigue in clinicians and patients part of its National Patient Safety Goals. Our facility has set up a committee to work on compliance of this new standard. Specific questions were compiled and the committee went to each of the units/departments asking these questions and has come up with ways to reduce the risk of alarm fatigue. Our facility has a policy in place that is reviewed and updated as needed.

Education of the staff on prevention of nuisance alarms by far is the most important thing any facility can do in my opinion. Educating the patient to keep devices in place and that it is fitted correctly at all times is just as important. Being able to adjust alarms according to the individual patient’s needs in reducing alarm fatigue helps their condition improve. When a new piece of equipment is purchased and presented for orientation and competencies, alarms are part of the process on settings and adjustments. Clinical engineering is responsible for the testing of these alarms on a regular timeframe. With these processes done and monitored by charge nurses, shift coordinators, and others during patient rounding reduces the amount of alarms as well.

“Capnography and pulse oximetry used together improves patient outcomes.”

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Best of Both Worlds
Capnography and pulse oximetry used together improves patient outcomes. Those patients who go through medical procedures requiring conscious sedation are now monitored with capnography to add that extra step of safety. Even though these patients have someone with them at all times there may be times where situations draw the attention away from the patient’s respiratory status which could lead to change in the patient condition causing decompensation. With capnography, these situations will be avoided.

News articles in recent years have shown patients undergoing procedures have been over sedated and not properly monitored due to lack of education of the caregiver to properly monitor the patient. It is my belief based on information given in those articles that pulse oximetry in conjunction with capnography would have prevented these poor outcomes. A final note, monitoring devices are only as good as the knowledge and training that is applied to qualified personnel. Training should always be done in the beginning of any new technology addition and annually for those high risk or low volume situations. Patient safety should be everyone’s concern 24/7/365.

Richard Kenney is Director, Respiratory Care Services, White Memorial Medical Center, Los Angeles.

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