The predicting ability of serum potassium to assess the duration of mechanical ventilation in critically ill patients

Javdan, Zahra; Talakoub, Reihanak; Honarmand, Azim; Golparvar, Mohammad; Farsani, Enayatolah Yadollahi

The predicting ability of serum potassium to assess the duration of mechanical ventilation in critically ill patients

Authors

¹ Department of Anesthesiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

² Department of Anesthesiology, School of Medicine, Anesthesia and Critical Care Research Center, Alzahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran

³ Faculty of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran

Abstract

Background: No previous study has been done to evaluate the admission serum potassium level as a predictor of morbidity or need for mechanical ventilation. The aim of this study is to determine the predictive ability of serum potassium on admission, in critically ill trauma patients, and to evaluate the relation of the potassium level to organ failure, length of stay, ventilator need, and duration of mechanical ventilation.
Materials and Methods: A prospective, observational study was done on 100 patients >16 years old, admitted to the Medical-Surgical Intensive Care Units (ICU), for over one year. Patients were classified into Group A: Patients who required equal or less than five days of mechanical ventilation and Group B: Patients who required more than five days of mechanical ventilation. The total serum potassium concentrations were measured and the Sequential Organ Failure Assessment (SOFA) score was recorded at the time of admission to the ICU, when connected to the ventilator, and then at the time of weaning from the ventilator.
Results: There was no significant difference between the Serum K concentrations between the two groups, on admission. However, there were significant difference between the Serum K concentrations at times of receiving and weaning from mechanical ventilation (MV) between the two groups. We found the best cut-off point of 3.45 for serum potassium concentration, to predict the need for longer duration of MV.
Conclusion: Development of hypokalemia during an ICU stay is associated with the need for mechanical ventilation. Monitoring of the serum potassium levels may be a good prognostic factor for the requirement of mechanical ventilation.

Keywords

References

1.	Lermitte J, Garfield MJ. Weaning from mechanical ventilation. CEACCP 2005;5:113-7.
2.	Boles JM, Bion J, Connors A, Herridge M, Marsh B, Melot C, et al. Weaning from mechanical ventilation. Eur Respir J 2007;29:1033-56.
3.	Arend W, Drazen J, Larusso N, Armitage J, Clemmons D. Renal Diseases. Cecil's Text book of Medicine. Elsevier Publication; 2008. p. 839-40.
4.	Gennari FJ. Disorders of potassium homeostasis. Hypokalemia and hyperkalemia. Crit Care Clin 2002;018:273-88, vi.
5.	Gennari FJ. Hypokalemia. N Engl J Med 1998;339:451-8.
6.	Beal AL, Scheltema KE, Beilman GJ, Deuser WE. Hypokalemia following trauma. Shock 2002;18:107-10.
7.	Vincent JL, Moreno R, Takala J, Willatts S, De Mendonça A, Bruining H, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine. Intensive Care Med 1996;22:707-10.
8.	Vincent JL, de Mendonça A, Cantraine F, Moreno R, Takala J, Suter PM, et al. Use of the SOFA score to assess the incidence of organ dysfunction/failure in intensive care units: Results of a multicenter, prospective study. Working group on"sepsis-related problems" of the European Society of Intensive Care Medicine. Crit Care Med 1998;26:1793-800.
9.	Honarmand A, Safavi M, Moradi D. The use of infection probability score and sequential organ failure assessment scoring systems in predicting mechanical ventilation requirement and duration. Turkish J Trauma Emerg Surg 2009;15:440-7.
10.	Safavi M, Honarmand A. Adimission hypomagnesemia- impact on mortality or morbidity in critically ill patients. Middle East J Anesthesiol 2007;19:645-60.
11.	Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology 1982;143:29-36.
12.	Oh TE, Hutchinson R, Short S, Buckley T, Lin E, Leung D. Verification of the acute physiology and chronic health evaluation scoring system in a Hong Kong intensive care unit. Crit Care Med 1993;21:698-705.
13.	McNeil BJ, Hanley JA. Statistical approaches to the analysis of receiver operating characteristic (ROC) curves. Med Decis Making 1984;4:137-50.
14.	Smith JS Jr. Hypokalemia in resuscitation from multiple trauma. Surg Gynecol Obstet 1978;147:18-20.
15.	Grace GT, Shin B, Levin P, Stone HH. Immediate post-traumatic hypokalemia. Curr Surg 1988;45:463-4.
16.	Vanek VW, Seballos RM, Chong D, Bourguet CC. Serum potassium concentrations in trauma patients. South Med J 1994;87:41-6.
17.	Halter JB, Beard JC, Porte D Jr. Islet function and stress hyperglycemia: Plasma glucose and epinephrine interaction. Am J Physiol 1984;247:E47-52.
18.	Desborough JP. The stress response to trauma and surgery. Br J Anaesth 2000;85:109-17.
19.	Ferreira FL, Bota DP, Bross A, Mélot C, Vincent JL. Serial evaluation of the SOFA score to predict outcome in critically ill patients. JAMA 2001;286:1754-8.
20.	Bernard GR. Quantification of organ dysfunction: Seeking standardization. Crit Care Med 1998;26:1767-8.

Advanced Biomedical Research