Comparative study of factors that contribute to the severity of metabolic alkalosis in a surgical ICU

Introduction

This is a comparative study of factors involved in the development of acid–base disorders in surgical patients. The aim of this study was to isolate factors that may affect the severity of alkalosis, the prolongation of hospitalization and the final outcome in patients admitted to an ICU.

Methods

Data were collected retrospectively from the electronic database of the surgical ICU of Hippocration Hospital, Athens, Greece. Inclusion criteria were defined as patients that developed metabolic alkalosis (pH >7.45 and [HCO₃^-] >24) at a certain time during their hospitalization. Patients were divided into two groups; group I included those with 7.45 <pH ≤ 7.55 and group II those with pH >7.55. Statistical analysis was performed between groups with regard to gender, age, type of surgery, blood urea concentration, white blood cell count, hematocrit, APACHE II score, serum potassium concentration, creatinine levels, total bilirubin levels, the presence of sepsis criteria, the recurrence of the disorder, the need for mechanical ventilation, the total days of the disorder, the length of hospital stay, the post-admittance day when the maximum pH was recorded, the post-surgery day of maximum pH, the use and the quantity of furosemide administration, the use and quantity of dobutamine administration, the use of human albumin and the survival. Statistical analysis was performed with the use of chi-square for comparison of data.

Results

Data charts from 1999 to 2005 were reviewed. In total, 987 patients were admitted to the ICU in this time period. Of these, 239 (24.2%) patients developed metabolic alkalosis at a certain time in their course. Group I included 210 patients (87.9%) and group II included 29 patients (12.1%). From the parameters that were analyzed, statistical significance was observed between the two groups in the value of the blood urea concentration, in the amount of sepsis criteria that were present and in the development of recurrence. We did not observe a statistical difference between the groups in creatinine levels, in the furosemide quantity or in serum potassium concentration.

Conclusion

The severity of metabolic alkalosis is affected by renal function as expressed by blood urea concentration and the severity of sepsis–septic shock. Moreover, unlike what we expected, furosemide administration did not prove of importance in the development of the alkalosis in this study.