Journal of Medical and Surgical Intensive Care Medicine 2010 , Vol 1, Issue 3
Can Gastric Tonometry be Used to Determine Weaning Failure?
Ömer Faruk Baysal 1 , Güven Çelebi 2 , Hakan Büyükoğlan 3 , Murat Sungur 4 , Muhammet Güven 4
1OSM Ortadoğu Hastanesi, İç Hastalıkları Kliniği, Şanlıurfa, Turkey
2Zonguldak Karaelmas Üniversitesi Tıp Fakültesi, Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Anabilim Dalı, Zonguldak, Turkey
3Erciyes Üniversitesi Tıp Fakültesi, Göğüs Hastalıkları Anabilim Dalı, Kayseri, Turkey
4Erciyes Üniversitesi Tıp Fakültesi, İç Hastalıkları Anabilim Dalı Yoğun Bakım Bilim Dalı, Kayseri, Turkey

Aim: Despite the advances, weaning from mechanical ventilation is an important problem in the daily operation of intensive care units (ICUs). The aim of this study was to measure the changes in intramucosal pH (pHi) and PCO2 of gastric juice (PiCO2) and to determine the value of these variables in order to  predict weaning failure in ICU patients.

Material and Methods: Forty (20 male, 20 female) patients considered ready to be weaned from mechanical ventilation (MV) were studied. All patients were on pressure support MV for at least 2h before the weaning trial. PiCO2 was determined with a tonometer and monitor. At the beginning of the weaning, MV was discontinued and extubation was performed after 2h of T-piece trial. Patients were followed for at least 24h.

Results: While 28 patients were successfully weaned, weaning failed in 12 patients. The initial SaO2 levels were significantly higher in successful cases (p<0.05). In the successful group, initial PiCO2 levels were lower than those in the failure group (39.70±13. 03 and 47.01±10.95), but this difference was not statistically significant (p>0.05). pHi (7.319±0.12 and 7.12±0.21 p=0.002) and SaO2 levels (96.87±2.83 and 93.92±3.47, p<0.05) were found significantly low at the post-weaning 6th h in the failure group. PiCO2 was high in the failure group, but this difference was not significant (46.39±16.92 and 63.01±30.14, p>0.05). The best parameters showing weaning failure were initial PaCO2, final pHi, final PiCO2 levels and ΔpHi. 

Conclusion: Weaning failure was associated with gastric intramucosal acidosis. It was found that there was an increase in PiCO2 or a decrease in pHi in patients with weaning failure. However, predictive values of gastric tonometric measurements were not sufficient to decide on reintubation. The results obtained after 6th h did not give further information about weaning failure. Thus, a follow-up period consisting of 6 h may be adequate to assess weaning outcomes.

Keywords : Gastric tonometry, weaning failure, mechanical ventilation, gastric intramucosal acidosis