A study of serum potassium level in adult patients after Elective gastrointestinal and hepatobilliary surgery at Kenyatta national hospital

Abstract

BACKGROUND Disturbance in potassium homeostasis pressenting as either hypokalaemia or hyperkalaemia is a known complication of gastrointestinal amd hepatobilliary surgery. factors that predispose to development of hypokalaemia incluude; dehydration. inadequate potassium intake, administration of loop diuretics, nasogiastric tube drainage and postoperative fluid losses through vomiting and gastrointestinail stomas. Overzealous postoperative potassium supplementation, transfusion of old bf1ood, obligatory oliguria and non steroidal anti inflammatory drugs can lead to hyperkalaccrnia. OBJECTIVE The aim of this study was to evaluanc the magnitude of potassium derangements after gastrointestinal and hepatobilliary surgeery. identify the associated factors and relate it to postoperative recovery. METHODOLOGY The study population consisted of patiernts scheduled for gastrointestinal and hepatobilliary surgery. Those who met inclusion criteria: and signed informed consent forms were recruited in the study. Two milliliters of venous bloods was taken for potassium measurement 24 hours before surgery and there after daily up uo fifth postoperative day. Fluid input and output was monitored and the amount and type recorded daily. Surgical wound was inspected daily from 24 hours after surgery to seventh postojperative day for signs of surgical site infection and wound dehiscence. Diagnosis of surgicml site infection was based on presence of pus and cellulitis of the surrounding skin. Pus swrab for culture and sensitivity was taken from wounds that had signs of infection. RESULTS A total of 100 patients were recruited. Fifty five percent (55%) of these patients developed hypokalaemia during the five day postoperative follow up. No patient developed hyperkalaemia in this study. Hypokalaemia most commonly developed: ,on the first postoperative day (55%) and lasted for 3 days in 45.5%. Hypokalaemia occurred muore frequently in patients with obstructive jaundice, carcinoma of the stomach and nasogastric: drainage of more than 1Ll24 hours. The amount of intravenous fluid given was within normal required range as per body weight. This ranged between 2.5litres t03.0 litres/24hrs.however dehydration was present in majority of patients on the first postoperative day as evidenced Iby low urine output « 1mls/kgihr). This low urine output on the first postoperative day could I have been due to body response to trauma leading to obligatory oliguria. Urine output was found to have a significant positive correlation with level of serum potassium. Among the 55 patients with hypokalaernia, 17(31 %) were treated by administration of intravenous potassium: chloride while 3R(69%) recovered spontaneously without potassium replacement. The infecution rate in this study was 27%. Of these, 72% had hypokalaemia. Seventy one percent (771%) of the patients with wound dehiscence had hypokalaemia. CONCLUSIONS Prevalence of hypokalaemia at Kenyatta National Hospital after gastrointestinal and hepatobiliary surgery is 55%. hyperkalaermia did not occur in this study. In this study patients, with obstructive jaundice had a higher coccurrence of hypokalaemia. Not all patients with hypokalaemia require treatment with intraivenous potassium chloride.