Capnography Captures Ventilation, Perfusion, and Metabolic Status to Support Positive Patient Outcomes

Have you incorporated capnography into your patient care yet? Think about what your algorithm is for vital signs and diagnosis monitoring. Ask yourself: How do you determine which data means the most, as well as what comes first or second? As clinicians, we are conditioned to use certain pieces of patient data, but are challenged with effectively evaluating three main aspects of patient status — ventilation, perfusion, and metabolic status.1-2

Capnography is a monitoring tool designed to help you better monitor your patients and improve positive outcomes while providing you with the insight you need on ventilation, perfusion, and metabolic status.1-2 Microstream™ technology is designed for early alerts3-4, accurate measurements3,5-7, and ease-of-use8.

Why capnography measurements support real-time patient treatment decisions

Capnography has been proven to effectively measure ventilation, perfusion, and metabolic status of patients.1-2 Key features of capnography include the waveform, which is instantaneous and useful in informing on a patient’s real-time respiratory status and airway structure. If a patient stops breathing, then the waveform flattens as shown in Figure 1 below.  

If perfusion begins to decrease, the end-tidal carbon dioxide (etCO2) waveform also drops as shown in Figure 2 below. Additionally, the waveform notifies of dips in the alveolar plateau (curare cleft Figure 3) below as the patient's diaphragm starts working again with the paralytic beginning to wear off.

Pulse oximetry is a helpful tool, but it is not without its limitations including lag.9,10 Noninvasive blood pressure (NIBP) is also not without its issues if the tubing is moved or the patient is in-motion. Applying technology such as the Microstream™ capnography sampling lines to your patient allows for continuous waveform capnography and, again, providing the three indicators of your patients’ ventilation, perfusion, and metabolic status.1-2

Related: Read more on using sampling line technology for accurate etCO2  measurement.

How Microstream™ capnography sampling lines capture respiratory rate for improved effectiveness

Ensuring consistency in measuring respiratory rate is essential, but manually counting and measuring respiratory rate accurately is sometimes challenging. Capnography allows the task to be cognitively offloaded to equipment. Microstream™ technology supports these measurements by capturing the mean respiratory rate over the previous 20 seconds and accounts for potential disruptions like talking. Capnography also captures rising respiratory rate from a patient experiencing shock or becoming increasingly sick.

Capnography is also the only tool that captures the three vital pieces of patient information in real-time while offering the capability to deliver oxygen.1 Together, reliable measurements with integrated oxygen delivery helps you get the complete picture of your patient’s respiratory status.

Microstream™ capnography sampling lines with oxygen delivery — in addition to monitoring respiratory rate and ventilatory status —continuously provides patient status feedback.

Related: Learn more on addressing normal and abnormal etCO2 capnography waveforms.

1. Aminiahidashti H., Shafiee S., Sazgar M. Applications of end-tidal carbon dioxide (etCO2) monitoring in emergency department; a narrative review. Emergency. 2018. 2018; 6(1): e5.
2. Cereceda-Sánchez, Francisco & Molina-Mula, Jesus. (2017). Capnography as a tool to detect metabolic changes in patients cared for in the emergency setting. Revista Latino-Americana de Enfermagem. 25. 10.1590/1518-8345.1756.2885.
3. Maddox R, Williams CK, Oglesby H, et al. Clinical experience with patient-controlled analgesia using continuous respiratory monitoring and a smart infusion system. Am J Health Syst Pharm. 2006;63(2):157-164.
4. Chung F, Wong J, Mestek ML, Niebel KH, Lichtenthal P. Characterization of respiratory compromise and the potential clinical utility of capnography in the post-anesthesia care unit: a blinded observational trial. J Clin Monit Comput. June 2019.
5. Ishiwata T., Tsushima K., Fujie M, Suzuki K., Hirota K., Abe M., Kawata N., Terada J., Tatsumi K.. End-tida capnographic monitoring to detect apnea episodes during flexible bronchoscopy under sedation. BMC Pulm. Med.. BMC Pulmonary Medicine. 2017. 17:7.
6. Paresh, Mehta, Gursimran Kochhar, Mazen Albeldawi, Brian Kirsh, Maged Rizk, Brian Putka, Binu John, Yinhong Wang, Nicole Breslaw, BSN RN, Rocio Lopez, John Vargo, MPH J MD. Capnography Monitoring in Routine EGD and Colonoscopy With Moderate Sedation: A Prospective, Randomized, Controlled Trial.. Am J Gastroenterol. 2016. 111:395.
7. Klare, Peter, Reiter, et al. Capnographic monitoring of midazolam and propofol sedation during ERCP:a randomized controlled study (EndoBreath Study). Endoscopy. 2016;48(01):42-50.
8. Khanna A, Overdyke F, Greeing C, Stefano P, Buhre W. Respiratory depression in low acuity hospital settings – Seeking answers from the PRODIGY trial, Journal of Critical Care 47 (2018) 80-87.
9. Weinger MB. Dangers of postoperative opioids. APSF Newsletter. 2006; 21: 61–88.
10. Fu ES, Downs JB, Schweiger JW, Miguel RV, Smith RA. Supplemental oxygen impairs detection of hypoventilation by pulse oximetry. Chest. 2004; 126: 1552–8.

The Microstream™ capnography monitoring system should not be used as the sole basis for diagnosis or therapy and is intended only as an adjunct in patient assessment.

About the Author

Chris has been a Paramedic/Firefighter in EMS for over 21 years. He has been in pre-hospital and in-hospital education for the past 16 years. He is currently working as an EMS Supervisor and Training Officer along with being affiliate faculty with the Virginia Commonwealth University Paramedic Program.

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