End-inspiratory rebreathing reduces the end-tidal to arterial PCO2 gradient in mechanically ventilated pigs
| Autor: | James Duffin, Anne Battisti-Charbonney, Matthew Machina, Joseph A. Fisher, Jorn Fierstra, Leonid Minkovich |
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| Rok vydání: | 2011 |
| Předmět: |
medicine.medical_specialty
Swine business.industry Partial Pressure Respiration Arteries Partial pressure Carbon Dioxide Critical Care and Intensive Care Medicine Respiration Artificial End tidal pCO2 Respiratory failure Anesthesia Internal medicine Breathing Cardiology medicine Animals Arterial blood Arterial pCO2 business Lung Monitoring Physiologic |
| Zdroj: | Intensive Care Medicine. 37:1543-1550 |
| ISSN: | 1432-1238 0342-4642 |
| DOI: | 10.1007/s00134-011-2260-y |
| Popis: | Noninvasive monitoring of the arterial partial pressures of CO(2) (PaCO(2)) of critically ill patients by measuring their end-tidal partial pressures of CO(2) (PETCO(2)) would be of great clinical value. However, the gradient between PETCO(2) and PaCO(2) (PET-aCO(2)) in such patients typically varies over a wide range. A reduction of the PET-aCO(2) gradient can be achieved in spontaneously breathing healthy humans using an end-inspiratory rebreathing technique. We investigated whether this method would be effective in reducing the PET-aCO(2) gradient in a ventilated animal model.Six anesthetized pigs were ventilated mechanically. End-tidal gases were systematically adjusted over a wide range of PETCO(2) (30-55 mmHg) and PETO(2) (35-500 mmHg) while employing the end-inspiratory rebreathing technique and measuring the PET-aCO(2) gradient. Duplicate arterial blood samples were taken for blood gas analysis at each set of gas tensions.PETCO(2) and PaCO(2) remained equal within the error of measurement at all gas tension combinations. The mean ± SD PET-aCO(2) gradient (0.13 ± 0.12 mmHg, 95% CI -0.36, 0.10) was the same (p = 0.66) as that between duplicate PaCO(2) measurements at all PETCO(2) and PETO(2) combinations (0.19 ± 0.06, 95% CI -0.32, -0.06).The end-inspiratory rebreathing technique is capable of reducing the PET-aCO(2) gradient sufficiently to make the noninvasive measurement of PETCO(2) a useful clinical surrogate for PaCO(2) over a wide range of PETCO(2) and PETO(2) combinations in mechanically ventilated pigs. Further studies in the presence of severe ventilation-perfusion (V/Q) mismatching will be required to identify the limitations of the method. |
| Databáze: | OpenAIRE |
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