Sunday, June 11, 2006


Checked another prisoner. Took a kid with some scrapes from falling off his bike to the hospital. Mom insisted on the ambulance.

Got lots of work done on my capnography site today. I'm leading a journal club discussion in another week or so on some capnography articles. Very interesting. One article points out that supplemental oxygen can obscure impedending ventilatory crisis unless you have capnography. Pulse oximetry is only good without supplemental 02.

Here's the article conclusions:

Microstream capnography improves patient monitoring during moderate sedation: a randomized, controlled trial.

Pediatrics. 2006 Jun;117(6):e1170-8.

CONCLUSIONS: The results of this controlled effectiveness trial support routine use of microstream capnography to detect alveolar hypoventilation and reduce hypoxemia during procedural sedation in children. In addition, capnography allowed early detection of arterial oxygen desaturation because of alveolar hypoventilation in the presence of supplemental oxygen. The current standard of care for monitoring all patients receiving sedation relies overtly on pulse oximetry, which does not measure ventilation. Most medical societies and regulatory organizations consider moderate sedation to be safe but also acknowledge serious associated risks, including suboptimal ventilation, airway obstruction, apnea, hypoxemia, hypoxia, and cardiopulmonary arrest. The results of this controlled trial suggest that microstream capnography improves the current standard of care for monitoring sedated children by allowing early detection of respiratory compromise, prompting intervention to minimize hypoxemia. Integrating capnography into patient monitoring protocols may ultimately improve the safety of nonintubated patients receiving moderate sedation.

Bottom Line for EMS:

Capnography provides early warning of respiratory compromise.

Supplemental oxygen impairs detection of hypoventilation by pulse oximetry.

Chest. 2004 Nov;126(5):1552-8.

CONCLUSION: Hypoventilation can be detected reliably by pulse oximetry only when patients breathe room air. In patients with spontaneous ventilation, supplemental oxygen often masked the ability to detect abnormalities in respiratory function in the PACU. Without the need for capnography and arterial blood gas analysis, pulse oximetry is a useful tool to assess ventilatory abnormalities, but only in the absence of supplemental inspired oxygen.

Bottom Line for EMS:

Without capnography, supplemental 02 can obscure impending respiratory problems.

Concordance between capnography and arterial blood gas measurements of carbon dioxide in acute asthma.

Ann Emerg Med. 2005 Oct;46(4):323-7.

CONCLUSION: In adult asthmatic patients with acute exacerbations, concordance between PetCO2 measured by capnography and PaCO2 measured by arterial blood gas was high. These findings must be validated before capnography replacement of arterial blood gas as an accurate means of assessing alveolar ventilation in acute asthma is recommended.

Bottom Line for EMS:

Capnography may provide a reading as accurate as ABGs.