ARTERIAL BLOOD pH

LOW PH AS PREDICTOR OF PROGNOSIS

Abstract

Background: Arterial blood gas analysis is the most commonly performed investigation in intensive care unit(ICU) as the changes in acid-base balance are common in critically ill patients. Changes in pH are directly related to severity of disease. Keeping in view our clinical experience and literature search, we assume that patients whose pH is less than 7 at any time in the course of disease carries poor prognosis. Design: Quasi experimental study. Setting: ICUs of Combined Military Hospital Rawalpindi and Combined Military Hospital Multan. Period: From 1st Jan 2006 to 6th Aug 2007 and 7th Aug 2007 to 31st May 2010 respectively. Material and Methods: All the patients having pH less than 7 at any time in the course of disease were considered and patient having otherwise fair state of health before recent insult were included. Moribund terminally ill patient were excluded. Results: All the thirty patients needed intubation and ventilation except one who remained conscious despite having pH. 6.95. Twenty two patients (73.4%) died and eight patients (26.6%) survived. All patients who survived were diabetic except one having tracheal stenosis. All patients who died were non diabetic. Only one non diabetic patient was among the survivor. Survival among diabetic patient as group was 100%(7/7). Conclusions: Patients having pH below 7 at any time in the course of disease carry poor prognosis especially if they are non diabetic. Diabetic has best prognosis. However it is a small study of thirty cases only, further multi centre studies are needed to demonstrate the co-relation of pH with prognosis prediction.