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By Sudi Shatha Harbool, NREMT
Oxygen, nitric oxide and carbon dioxide are primary respiratory gasses that play an essential role in cellular metabolism, vascular regulation, tissue oxygenation, as well as additional key biological processes [1]. Carbon dioxide, in particular, efficiently provides valuable insights into a person’s respiratory condition.
Monitoring carbon dioxide levels through capnography allows for instantaneous feedback on the quality of ventilations and perfusion. It offers a noninvasive method for clinical personnel to confirm correct placement of extraglottic airway devices (e.g., supraglottic airways), monitor endotracheal intubations, evaluate patients with obstructive airway diseases (e.g., COPD), and monitor patients under procedural sedation [2].
Capnography as a biofeedback tool is explored in clinical practice, however, its use in the prehospital setting has significant potential that is yet to be fully realized.
|More: 5 things to know about capnography and respiratory distress
Biofeedback therapy
Formally defined in the 1960s, biofeedback therapy emerged as a collective effort between psychologists and physiologists, aimed at helping patients exert a greater degree of control over their blood pressure, brain activity, heart rate and other normally involuntary physiological processes [3]. Biofeedback therapy is often needed for patients who engage in unconscious actions that negatively impact the body, addressing the issue by making the adverse physiological impacts visible to the patient.
Figure 1 illustrates the general method of biofeedback [4].
The individual is observed through a device that captures unintended actions (e.g., negative respiratory patterns that mimic hyperventilation). This data is then analyzed, and the subject receives either auditory or visual cues to create awareness and alert them to modify their responses (e.g., the patient is shown their live capnography waveform, showing them decreased carbon dioxide levels, which prompts them to consciously think about their breathing pattern and adjust accordingly) [5].
This cycle allows for biofeedback therapy to generally operate in a negative feedback loop. Data collected from the therapy session is then stored and utilized for further research and testing.
Biofeedback has several applications as well. Notable therapies include Electromyography (EMG) to measure muscle tension, thermal biofeedback to detect skin temperature, and electroencephalography (EEG) to measure brain activity [6]. Biofeedback is also used to alleviate symptoms associated with a wide range of disorders, such as anxiety, PTSD and ADHD [7].
Biofeedback using capnography in the clinical setting
Capnography tracks breathing rate, rhythm and depth, as well as end tidal carbon dioxide (EtCO2) [10]. Capnography as a biofeedback tool is currently being explored in various clinical settings, such as therapy centers, mental health clinics and research facilities. Several dysfunctional breathing disorders, such as hyperventilation, hypoventilation, asthma and patterned apnea can be monitored through capnography [8,9]. These breathing patterns can be a reaction to an external stimulus, such as psychophysiological factors (e.g. stress, fear) or situational triggers, but can also be attributed to several chronic conditions that impact breathing, such as chronic pain syndromes (e.g., fibromyalgia), neuromuscular disease, obesity and chronic heart failure [11].
In the clinical setting, treatment begins with the clinician evaluating the patient’s breathing pattern, and any abnormalities, such as those listed above, are recorded on the Capnogram Disordered Breathing Scale (CDBS) to measure the severity of the breathing abnormality [12]. The capnography device is connected to the patient and measures all ventilatory parameters as the clinician guides the patient through a tailored breathing exercise [13]. Visualizing the impact of the breathing exercise on these ventilatory parameters allows the patient to become more cognizant of their breathing pattern. The session then ends with the clinician debriefing with the patient, answering any questions and discussing the capnography readout [12]. Several sessions are often necessary for patients to learn how to better control their breathing pattern, and a home exercise program can also be provided to patients who are in need of further guided breathing techniques outside of the healthcare facility.
Improving the prehospital patient care experience
The techniques used in the clinical setting can be easily transferred to the prehospital setting to enhance the patient care experience. Capnography biofeedback therapy can be a valuable tool for patients experiencing respiratory emergencies. EMS personnel can instruct patients to monitor their capnography waveform, as well as explain the meaning behind what they are visualizing. EMS can also guide the patient further, and help them with breathing techniques to further alleviate the situation and diffuse stress. This combination of direct biofeedback as well as EMS instruction can allow the patient to adjust their breathing pattern to minimize adverse effects of their dysfunctional breathing pattern.
While the use of capnography as a biofeedback tool is still in its developmental stages, it is crucial for the EMS community to understand its potential applications. By leveraging the simplicity and effectiveness of capnography, EMS providers can significantly improve patient outcomes by alleviating certain respiratory conditions and enhancing the overall quality of care.
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ABOUT THE AUTHOR
Sudi Shatha Harbool is a student at Case Western Reserve University, majoring in Biology and Psychology, with minors in Chemistry, French and Social Justice. Sudi is passionate about pursuing a career in medicine and dedicated to making a positive impact in the healthcare field.
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