Document Detail

Influence of alveolar ventilation changes on calculated gastric intramucosal pH and gastric-arterial PCO2 difference.
MedLine Citation:
PMID:  10229160     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To evaluate the influence of changes in alveolar ventilation on the following tonometry-derived variables: gastric intramucosal CO2 tension (PtCO2), gastric arterial CO2 tension difference (PgapCO2), gastric intramucosal pH (pHi) and arterial pH-pHi difference (pHgap). DESIGN: Clinical prospective study. SETTING: A medical intensive care unit in a university hospital. PATIENTS: Ten critically ill, mechanically ventilated patients requiring hemodynamic monitoring with pulmonary artery catheter. INTERVENTIONS: Gastric tonometer placement. A progressive increase in tidal volume (V(T)) from 7 to 10 ml/ kg followed by an abrupt return to baseline V(T) level. MEASUREMENTS AND MAIN RESULTS: Tonometer saline PtCO2 and hemodynamic data were collected hourly at various V(T) levels: H0 and H0' (baseline V(T) = 7 ml/kg), H1 (V(T) = 8 ml/kg), H2 (V(T) = 9 ml/kg), H3 (V(T) = 10 ml/kg), H4 (baseline V(T)). During the "hyperventilation phase" (H0-H3), pHi (p<0.01) and pHgap (p<0.05) increased but PgapCO2 remained unchanged. Cardiac output (CO) was not affected by ventilatory change. During the "hypoventilation phase" (H3-H4), pHi fell from 7.27+/-0.11 to 7.23+/-0.09 (p<0.01) and PgapCO2 decreased from 16+/-5 mm Hg to 13+/-4 mm Hg (p<0.05). V(T) reduction was associated with a significant cardiac output elevation (p<0.05). CONCLUSIONS: PaCO2 and PtCO2 are similarly influenced by the changes in alveolar ventilation. Unlike pHi, the PgapCO2 is not affected by ventilation variations unless CO changes are associated.
G Bernardin; P Lucas; H Hyvernat; P Deloffre; M Mattéi
Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Intensive care medicine     Volume:  25     ISSN:  0342-4642     ISO Abbreviation:  Intensive Care Med     Publication Date:  1999 Mar 
Date Detail:
Created Date:  1999-07-08     Completed Date:  1999-07-08     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7704851     Medline TA:  Intensive Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  269-73     Citation Subset:  IM    
Service de Réanimation Médicale, Hôpital de l'Archet, Nice, France.
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MeSH Terms
Blood Gas Analysis / methods
Carbon Dioxide / metabolism*
Critical Illness
Gastric Mucosa / blood supply*,  metabolism*
Hydrogen-Ion Concentration
Manometry / methods
Middle Aged
Prospective Studies
Respiration, Artificial*
Severity of Illness Index
Reg. No./Substance:
124-38-9/Carbon Dioxide
Comment In:
Intensive Care Med. 1999 Mar;25(3):249-51   [PMID:  10229156 ]

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