Thursday, March 26, 2009

Decreasing PaCO2: APRV optimization of settings.

  • First, assess the patients level of sedation, if sedation is used it should be titrated so the patient is easily awakened with light stimuli, and spontaneous breathing is promoted. 
  • Second, reassess expiratory flow make sure that T-PEFR is within 50-75% . If T-PEFR is greater than or equal to 75% and oxygenation is acceptable, consider increasing t-Low by 0.05-0.1 increments to achieve a 50% T-PEFR.
  • Third, if not contraindicated increase minute ventilation by increasing p-High or p-High and t-High.
  • Lastly, if oxygenation is acceptable and paCO2 is a concern the practitioner may increase minute ventilation by decreasing t-High and increasing p-High simultaneously. 
note- decreasing t-High will increase frequency however, mean airway pressure is sacrificed and less end expiratory lung volume is generated. The t-Low should be reassessed & titrated to allow for appropriate release time. 
Additionally, t-Low should not be extended solely to allow for paCO2 removal, increasing the t-Low may lead to alveolar derecruitment.