Pc Roberts

Evaluation of the 5-French saline paediatric gastric tonometer.

Objective: To evaluate the paediatric 5-French (Fr) saline-filled gastric tonometer. Design: (a) In vitro comparison of saline bath reference pCO2 with tonometric pCO2 measured by normal saline-filled and phosphate-buffered saline-filled 5-Fr tonometers, and by a recirculating gas tonometer. ( b) In vivo comparison of gastric intramucosal pCO2i, measured by normal saline-filled 5-Fr tonometer (NST) and simultaneously by recirculating gas tonometer (RGT) in ten paediatric intensive care patients. (c) In vivo comparison of pCO2i measured simultaneously by 2 NST 5-Fr tonometers, before and after enteral feeding, in ten paediatric intensive care patients. Measurements and main results: (a) Twenty consecutive measurements of pCO2 were made at constant reference pCO2 of 19, 38, 56, and 75 mmHg (2.5, 5.0, 7.5, and 10.0 kPa), respectively. The NST tonometer underestimated reference pCO2 by mean bias (limits of agreement) of 58 % (20 %), and the phosphate-buffered saline-filled tonometer by 6 % (26 %). The RGT showed mean bias 5.7 % with narrow limits of agreement (1.5 %). (b) In 50 paired (NST vs. RGT) in vivo measurements over pCO2i range 23–73 mmHg (3.0–9.7 kPa), the NST underestimated RGT pCO2i by a mean bias of 10 mmHg (1.3 kPa), with limits of agreement + /–10 mmHg (1.5 kPa). This resulted in NST consistently overestimating pHi and underestimating pCO2 gap (both P < 0.001). (c) One hundred simultaneous paired NST measurements were assessed (50 without, and 50 with enteral feeding). The mean biases (limits of agreement) were identical in the fasted and fed states 0.4 ± 6 mmHg, with no difference between the fed and fasting states (P = 0.7). Conclusions: There are inherent problems in the methodology of saline tonometry, which adversely affect the accuracy and reliability of the 5-Fr paediatric gastric tonometer in comparison to recirculating gas tonometry.

H2 blockers in the intensive care unit: ignoring the evidence? Telephone survey

Stress ulcers are gastroduodenal erosions that occur commonly in critically ill patients. Although once thought to be due to excess acid production, they are now thought to result from gastric mucosal ischaemia and the value of using pH altering drugs to prevent them has been questioned.1 Cook et al showed that only critically ill patients who have a coagulopathy or who are ventilated for more than 48 hours are at increased risk of developing serious bleeding due to stress ulceration.2 Prophylaxis is usually with either an H2 receptor antagonist or sucralfate, and these agents appear equally efficacious in terms of reducing bleeding complications.3 A recent meta-analysis has, however, shown that sucralfate is associated with a lower …