OBJECTIVE: To compare partial pressure of carbon dioxide (PCO2) measurements obtained by sampling gastric intraluminal air with those obtained by standard saline tonometry. DESIGN: Prospective, unblinded study. SETTING: Intensive care unit in a tertiary cardiac surgical center. PATIENTS: 20 patients undergoing cardiac surgery. INTERVENTIONS: Gastric tonometric catheters were inserted, gastric fluid was aspirated, and 100 cc of air was injected into the stomach. MEASUREMENTS: After an equilibration period of 30 min, samples of gastric air and saline were anaerobically aspirated and analyzed on a standard blood gas machine. The reproducibility of PCO2 measurements in a given patient was assessed by analyzing consecutive samples of gastric air and calculating the coefficient of variation (CV). RESULTS: PCO2 values measured in samples of gastric air (PCO2 air) were highly correlated with those derived by saline tonometry (PCO2ss)(r2 = 0.95, p = 0.0001); PCO2 air was significantly greater than PCO2ss (50 +/- 17 vs 48 +/- 17 mmHg, p = 0.0001). Intramucosal pH (pHi) calculated from PCO2 air was significantly lower than that calculated from PCO2ss (7.26 +/- 0.23 vs 7.28 +/- 0.24, p = 0.0001). Analysis of intermethod differences showed significant bias for both PCO2 (2.4 +/- 7.6 mmHg, mean +/- 2SD, bias +/- precision) and pHi ( -0.023 +/- 0.074, mean +/- 2SD, bias +/- precision). The within-subject variability of replicate PCO2 measurements in gastric air was low (CV = 2.6 +/- 0.8). CONCLUSION: We conclude that intraluminal PCO2 can be accurately determined in postoperative cardiac surgery patients by instilling air into the stomach and analyzing samples of gastric air on a standard blood gas machine, In comparison with saline tonometry, air tonometry consistently yields lower pHi values.
OBJECTIVE: To compare partial pressure of carbon dioxide (PCO2) measurements obtained by sampling gastric intraluminal air with those obtained by standard saline tonometry. DESIGN: Prospective, unblinded study. SETTING: Intensive care unit in a tertiary cardiac surgical center. PATIENTS: 20 patients undergoing cardiac surgery. INTERVENTIONS: Gastric tonometric catheters were inserted, gastric fluid was aspirated, and 100 cc of air was injected into the stomach. MEASUREMENTS: After an equilibration period of 30 min, samples of gastric air and saline were anaerobically aspirated and analyzed on a standard blood gas machine. The reproducibility of PCO2 measurements in a given patient was assessed by analyzing consecutive samples of gastric air and calculating the coefficient of variation (CV). RESULTS:PCO2 values measured in samples of gastric air (PCO2 air) were highly correlated with those derived by saline tonometry (PCO2ss)(r2 = 0.95, p = 0.0001); PCO2 air was significantly greater than PCO2ss (50 +/- 17 vs 48 +/- 17 mmHg, p = 0.0001). Intramucosal pH (pHi) calculated from PCO2 air was significantly lower than that calculated from PCO2ss (7.26 +/- 0.23 vs 7.28 +/- 0.24, p = 0.0001). Analysis of intermethod differences showed significant bias for both PCO2 (2.4 +/- 7.6 mmHg, mean +/- 2SD, bias +/- precision) and pHi ( -0.023 +/- 0.074, mean +/- 2SD, bias +/- precision). The within-subject variability of replicate PCO2 measurements in gastric air was low (CV = 2.6 +/- 0.8). CONCLUSION: We conclude that intraluminal PCO2 can be accurately determined in postoperative cardiac surgery patients by instilling air into the stomach and analyzing samples of gastric air on a standard blood gas machine, In comparison with saline tonometry, air tonometry consistently yields lower pHi values.
Authors: G Gutierrez; F Palizas; G Doglio; N Wainsztein; A Gallesio; J Pacin; A Dubin; E Schiavi; M Jorge; J Pusajo Journal: Lancet Date: 1992-01-25 Impact factor: 79.321
Authors: G R Doglio; J F Pusajo; M A Egurrola; G C Bonfigli; C Parra; L Vetere; M S Hernandez; S Fernandez; F Palizas; G Gutierrez Journal: Crit Care Med Date: 1991-08 Impact factor: 7.598