"Permissive hypoventilation" in a swine model of hemorrhagic shock

Sharven Taghavi, Senthil N. Jayarajan, Lucas M. Ferrer, Halley Vora, Conor McKee, Richard E. Milner, John P. Gaughan, Jay Dujon, Lars O. Sjoholm, Abhijit Pathak, Joseph F. Rappold, Thomas A. Santora, Steven R. Houser, Amy J. Goldberg

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Background: Many penetrating trauma patients in severe hemorrhagic shock receive positive pressure ventilation (PPV) upon transport to definitive care, either by intubation (INT) or bag-valve mask (BVM). Using a swine hemorrhagic shock model that simulates penetrating trauma, we proposed that severely injured patients may have better outcomes with "permissive hypoventilation," where manual breaths are not given and oxygen is administrated passively via face mask (FM). We hypothesized that PPV has harmful physiologic effects in severe low-flow states and that permissive hypoventilation would result in better outcomes. Methods: The carotid arteries of Yorkshire pigs were cannulated with a 14-gauge catheter. One group of animals (n = 6) was intubated and manually ventilated, a second received PPV via BVM (n = 7), and a third group received 100% oxygen via FM (n = 6). After placement of a Swan-Ganz catheter, the carotid catheters were opened, and the animals were exsanguinated. The primary end point was time until death. Secondary end points included central venous pressure, cardiac output, lactate levels, serum creatinine, CO2 levels, and pH measured in 10-minute intervals. Results: Average survival time in the FM group (50.0 minutes) was not different from the INT (51.1 minutes) and BVM groups (48.5 minutes) (p = 0.84). Central venous pressure was higher in the FM group as compared with the INT 10 minutes into the shock phase (8.3 mm Hg vs. 5.2 mm Hg, p = 0.04). Drop in cardiac output (p < 0.001) and increase in lactate (p < 0.05) was worse in both PPV groups throughout the shock phase. Creatinine levels were higher in both PPV groups (p = 0.04). The FM group was more hypercarbic and acidotic than the two PPV groups during the shock phase (p < 0.001). Conclusion: Although permissive hypoventilation leads to respiratory acidosis, it results in less hemodynamic suppression and better perfusion of vital organs. In severely injured penetrating trauma patients, consideration should be given to immediate transportation without PPV.

Original languageEnglish (US)
Pages (from-to)14-19
Number of pages6
JournalJournal of Trauma and Acute Care Surgery
Volume77
Issue number1
DOIs
StatePublished - Jul 2014
Externally publishedYes

Keywords

  • Prehospital intubation
  • hemorrhagic shock
  • penetrating trauma
  • swine model

ASJC Scopus subject areas

  • Surgery
  • Critical Care and Intensive Care Medicine

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