July - September 2006, Volume 2, Issue 3

Filipescu D, Luchian M, Raileanu I, Ghenu O

Early profile and clinical significance of hyperchloremic acidosis in patients undergoing cardiac surgery

Acta Endo (Buc) 2006, 2 (3): 295-306
doi: 10.4183/aeb.2006.295

Objectives: to determine the 24-hours profile and the clinical implications of hyperchloremic metabolic acidosis (HCMA) following cardiac surgery with cardiopulmonary bypass (CPB).\r\nSubjects and methods: prospective and observational study set in cardiac anesthesia and intensive unit. One hundred patients with cardiac procedures with CPB, mean age 56 years, mean body weight 71 kg, were enrolled. Sampling of arterial blood for gas, acid-base parameters (pH, carbon dioxide partial pressure, base excess, concentration of bicarbonate and anion gap) and serum electrolytes (sodium, potassium, chloride) were performed at four time points: 30 min after induction of anesthesia (T1), after completion of CPB (T2), at 6 hours (T3) and at 24 hours postoperatively (T4). The volume of fluids administered intraoperatively and 24 hours postoperatively as well as major complications: bleeding, arrhythmias and organ dysfunctions (renal, pulmonary or neurological) were also registered. For statistical analysis we used a t-test (p<0.05).\r\nResults: Seventy-three (73 %) of the patients developed metabolic acidosis during the observation period. Sixty-six (66 %) patients had HCMA. Mean chloride concentrations were at T1, T2, T3, and T4: 103 mmol/L, 113 mmol/L, 111 mmol/L and 108 mmol/L, respectively. The chloride concentration was significantly higher at T2 and T3 as compared to baseline. There were no statistical differences between patients with and without HCMA, neither in the amount and type of fluids administered perioperatively, nor in the incidence of bleeding, arrhythmias, and organ dysfunctions.\r\nConclusions: HCMA is common after cardiac surgery. It is a transient and benign acid-base disturbance. In our low risk cardiac surgery patients, HCMA was not associated with major postoperative complications.

Keywords: acid-base physiology, metabolic acidosis, chloride, cardiopulmonary bypass, cardiac surgery

Correspondence: Daniela Filipescu, MD, Department of Cardiac Anesthesia and Intensive Care, "C. C. Iliescu" Institute of Cardiovascular Diseases, Sos Fundeni 256-258, Bucharest, Romania, email: Danielafilipescu@b.astral.ro, phone/ fax: 0040213172472