By Darlene (Dee) Larimer, MS, RN

According to the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), which in January of 2001 revised its standards for monitoring patients sedated for procedures, “clinicians who provide moderate to deep sedation must be competent to manage the level of sedation deeper than the one intended. This is because drug metabolism in a given patient cannot be precisely predicted, and some patients may become more heavily sedated from a standard dose than others.” (Carroll,pg.58)

“End-tidal carbon dioxide monitoring refers to the noninvasive measurement of exhaled carbon dioxide. The term capnometry refers to the measurement and display of the concentration of exhaled carbon dioxide either as a percentage (%) or as partial pressure in millimeters of mercury (mmHg). If the gas measuring device also includes a calibrated, visual waveform recording of the concentrations of inspired and exhaled carbon dioxide that can be examined on a breath-by-breath basis or for long term trends, the instrument is called a capnograph.” (St John, pg 83)

Patricia Carroll writing in RN October, 2002 says “Capnography monitors ventilation, while pulse oximetry monitors only oxygenation. Capnography thus provides breath-to-breath feedback, and changes in breathing, like apnea, are reflected immediately. Changes in pulse oximetry can lag behind breathing changes. In procedural sedation, the nurse administering the sedating drugs monitors the patient during the procedure and stays with them during the recovery phase. JCAHO standards specifically require that heart rate and oxygenation are continuously monitored by pulse oximetry, and that respiratory rate and adequacy of pulmonary ventilation are also continually monitored. Simply watching for the rise and fall of the chest provides very little information about the effectiveness of the chest wall movements.” (Carroll, pg. 54, 58)

Capnography measures the Carbon Dioxide (CO2) in every breath to monitor air exchanges in the patient’s alveoli. “Measuring CO2 levels during procedural sedation can detect problems in lungs or airway and offers earlier warning signs of hypoventilation, respiratory depression, hyper metabolism, and hypo perfusion rather than monitoring Spo2 alone.” (Woomer, Berkheimer, pg.42) “A normal capnogram has a near zero baseline with a sharp rise, a plateau, then a sharp rapid down shift.” (Sandlin, pg.277) Looks like an upside down U. “The capnograph waveform plots the patient’s CO2 level on the vertical axis and the time on the horizontal axis. The highest point represents the end-tidal CO2-ETCO2- the concentration of CO2 at the end of exhalation, which provides a clinical estimate of alveolar CO2.” (Woomer, Berheimer, pg. 42)

Suggestions for intervention if any change from baseline are: “check the patient, stimulate the patient, consider withholding additional sedating medications, inform the practitioner, stop the procedure if necessary, and administer a reversal agent.” (Woomer, Berkheimer,pg. 42)

Is End-Tidal Carbon Dioxide Monitoring in your future? Consider the cost element, efficiency of the products available, additional monitoring devices needed, and education/competency for the staff involved.

REFERENCES USED

Carroll, Patricia “Procedural sedation- Capnography’s Heightened Role”, RN

October 2002 Vol.65, No 10

Sandlin, Debbie “Capnography for Nonintubated Patients: The Wave of the Future for Routine Monitoring of Procedural Sedation

Patients.” Journal of PeriAnesthesia Nursing August 2002 Vol 17, No 4

St John, Robert E. “End- Tidal Carbon Dioxide Monitoring” Critical Care Nurse August 2003 Vol 23 No 4

Woomer,James L. Berkheimer, David A. “Using Capnography to Monitor Ventilation” Nursing 2003 April Vol 33 No 4