DECEMBER 2010 Measuring LIFE & BREATH The benefits of capnography in EMS An exclusive supplement to JEMS sponsored by Oridion. A LOOK INSIDE TABLE OF CONTENTS 4 CAPNOGRAPHY BASICS An invaluable tool for providers & their patients Pat Brandt, RN 10 POSITIVE JUSTIFICATION A cost-benefit analysis of capnography use can prove value to patients & your budget Pat Brandt, RN 14 A FORM OF TRIAGE Vice President/Publisher Advertising Director Capnography use for the conscious & Jeff Berend Judi Leidiger non-intubated patient Bob Page, AAS, NREMT-P, CCEMT-P, NCEE Editorial Director Art Director 18 GOTHCA! A.J. Heightman, MPA, EMT-P Leah Bergman Challenging waveforms that could fool an expert Pat Brandt, RN Managing Editor Cover Photo Lauren Hardcastle Oridion INTRODUCTION THE ULTIMATE TREND SETTER By A.J. Heightman, MPA, EMT-P he 2010 AHA Guidelines for CPR and ECC have the earliest indication of hypoventilation, respiratory depression T a major new Class I recommendation for and respiratory failure. use of quantitative waveform capnography for Most importantly, changes in the capnography waveform confirmation and monitoring of endotracheal provide the earliest indication of apnea, upper airway obstruction (ET) tube placement. Real-time monitoring and optimization and laryngospasm. A glance at the waveform by a trained of CPR quality using physiologic parameters, such as partial provider allows them to instantly see a patient’s response to pressure of end-tidal carbon dioxide (PEtCO2), are encouraged. airway alignment maneuvers and further distinguish upper The guidelines also recommend the use of capnography PEtCO2 airway obstruction from laryngospasm. Providers can also easily values to monitor CPR quality, detect return of spontaneous recognize the curved waveform of obstructive lung disease, which circulation and guide vasopressor therapy during cardiac arrest indicates bronchospasm. (Class IIb). Capnography can also be used effectively to detect, assess In EMS circles, capnometry used to just be a tool for and triage victims of chemical terrorism. It’s helpful as an determining whether an ET tube was properly placed. It soon assessment and triage tool because chemical agents are primarily became the gold standard for this function. However, medical absorbed through the skin and respiratory tract and have their directors, educators and field crews in most EMS systems soon greatest effect on the central nervous and respiratory systems. realized that capnography was a multi-purpose assessment tool. Because EtCO2 waveforms and trends alert crews to Capnography is the only single-monitoring modality worsening conditions and allow them to intervene much earlier available to EMS crews that provides a visual reference to a to correct or reverse a critical condition, capnography is one of patient’s ABCs in less than 15 seconds, with a normal waveform the most important EMS assessment tools that can be carried in instantly telling us our patient’s airway is patent, they’re a critical care toolkit for conscious and unconscious patients. breathing, and they’re adequately perfusing. Pass this special supplement to December JEMS along to Capnography also provides the only direct, non-invasive your personnel and ensure your crews are fully utilizing all the measure of ventilatory status available to EMS crews and offers im­­portant capabilities offered by capnography. Measuring Life & Breath is an editorial supplement sponsored by Oridion and published by Elsevier Public Safety, 525 B Street, Ste. 1800, San Diego, CA 92101-4495; 800/266-5367 (Fed ID # 13-1958712). Copyright 2010 Elsevier Inc. No material may be reproduced or uploaded on computer network services without the expressed permission of the publisher. Subscription information: To subscribe to an Elsevier publication, visit www.jems.com. Advertising information: Rates are available on request. Contact Elsevier Public Safety, Advertising Department, 525 B Street, Ste. 1800, San Diego, CA 92101-4495; 800/266-536. MEASURING LIFE & BREATH 3 THE BASICS CAPNOGRAPHY BASICS An invaluable tool for providers & their patients Photo Fred Wurster & Al Kalbach Wurster Photo Fred By Pat Brandt, RN Capnography is now required in most EMS systems to ensure successful patient endotracheal intubation. he goal of this supplement is to review key are perfusing well. In addition, it gives you key infor- T aspects of capnography, its powerful assess- mation about the patient’s metabolic status, such as ment capabilities on intubated and conscious whether they have normal metabolic activity or if it patients, and its importance as a prehospital triage increased or decreased. and treatment guiding tool. This information, when combined with the Capnography provides valuable and rapid patient’s history and your physical assessment, can assessment information that greatly assists EMS provide you with an accurate working diagnosis of providers and enables them to develop, monitor the emergency condition. Once that clinical obser- and modify patient care plans. This valuable assess- vation is made, you can initiate the appropriate ment tool supplies immediate breath-to-breath treatment for that condition. Then you can con- information about the patient’s respiratory sta- tinue to observe the capnography trend and use it tus: Are they being adequately ventilated? Are they to assist you in determining the effectiveness of the breathing too quickly or slowly? Are they experi- treatment and guide you in continuing or adjusting encing bronchospasm? your treatment as required. Capnography also provides you with key infor- These outstanding assessment capabilities mation about the patient’s circulatory status, such exhibit why capnography is required in multiple as whether they have adequate cardiac output and states and on every ALS unit in Europe. 4 JEMS DEC. 2010 Definition Capnography represents Capnography offers a quantitative numerical read- ing and graphic waveform that measures, illustrates real-time information and documents your patient’s exhaled carbon diox- regarding CO exhalation ide (CO2). All living human beings produce CO2 as a 2 byproduct of metabolism. The carbon dioxide, once and respiratory rates. produced, is diffused into the blood and transported to the lungs via the circulatory system. It’s then released by the alveoli and eliminated from the body measured with arterial blood gases in patients with during exhalation. normal lung function and also in patients with Therefore, capnography enables you to eval- abnormal lung function due to conditions other uate the current status of the patient’s ventilatory, than a ventilation-perfusion mismatch. circulatory and metabolic systems by measuring In patients with a ventilation-perfusion mis- the exhaled CO2 and graphically depicting its path match, the gradient between the ventilation and of exhalation. the perfusion will widen based on the severity of the mismatch. In those cases, the EtCO2 should be used Capnography Use to trend the ventilatory status. An elevated EtCO2 Capnography not only provides you with a rapid level is typically an indication of hypoventilation or and reliable assessment of the patient’s ventilatory, increased metabolic activity. A low exhaled CO2 level circulatory and metabolic function, it also—and more importantly—represents real-time information FIGURE 1 regarding CO2 exhalation and respiratory rates. In the articles that follow, several actual cases will illustrate the effectiveness of capnography as an assessment and monitoring tool in the field. The measurement of CO2 content in each exha- lation reflects the CO2 produced by metabolism, transported by the circulatory system and exhaled by the respiratory system at the time of that particular breath. This allows you to make rapid adjustments in your treatment based on current information. may be an indication of hyperventilation, decreased cardiac output or poor pulmonary perfusion, which Application can occur in shock. It’s important you understand capnography’s The capnography waveform can be compared numerical readings and graphic waveforms to use to an ECG because the “normal” waveform has cer- it effectively. The numeric readings are derived tain rules. Each waveform represents the various from a point in the respiratory cycle known as the phases of inhalation and exhalation and is divided end-tidal CO2 (EtCO2). This is the point at the end into four phases, (see Figure 1 above). of exhalation when the CO2 reaches its highest con- Phase I (A–B) occurs at the beginning of exha- centration. This concentration is generally in the lation when no CO2 is present in the upper airway, range of 35–45 mmHg. trachea, posterior pharynx, mouth and nose. No gas The reading closely correlates to the CO2 levels exchange occurs in these areas, so this “dead space” Hyperventilation Example This is a hyperventilation waveform. Note the high RR and low EtCO2. Figure Pat Brandt Figure MEASURING LIFE & BREATH 5 THE BASICS CONTINUED to the presence of more CO2 per breath, (see Fig- FIGURE 2 ure 3, p. 8). There are, however, other reasons for an increased EtCO2 and increased waveform height. These include a decreased tidal volume with or with- out a decreased respiratory rate, an increased meta- bolic rate and an increased body temperature. The hyperventilation waveform, related to an increased respiratory rate, will have a higher number of waveforms with a decreased height of the waveforms due to the presence of less CO2 per breath, (see Figure 2). As mentioned earlier, other reasons for a decreased EtCO2 and decreased wave- form height include increased tidal volume, a decreased metabolic rate, a decrease in circulation and hypothermia. The bronchospastic capnography waveform is is represented as the flat baseline of the waveform. recognized by a shark-fin shape instead of the nor- Phase II (B–C) is the ascending phase. During mal box-like waveform, (see Figure 4, p. 9). This is this phase, CO2 from the alveoli begins to reach the because bronchospasm causes a slower and more upper airway and mix with the dead space air, caus- erratic emptying of CO2 from the alveoli, which ing a rapid rise in the amount of CO2 detected. results in a slower rise in the expiratory upstroke.