Metabolic alkalosis after pediatric cardiac surgery.
OBJECTIVE
To determine occurrence, causes and associated mortality of postoperative metabolic alkalosis in pediatric cardiac surgery.


METHODS
We retrospectively analyzed clinical and biochemical variables of 186 consecutive cardiac operations other than ductal ligations on children less than 2 years old during the years 1999 and 2000. Metabolic alkalosis was defined as a pH>7.48 corrected for PCO2, with a base excess > or =5 on two or more consecutive measurements during an 8h period.


RESULTS
Median age was 15 weeks [range 2 days-95 weeks] and median weight 4.5 kg [range 2.1-15.7 kg]. In 157 cases, cardiopulmonary bypass was used. In 92 [49%] procedures, metabolic alkalosis occurred with the highest corrected pH 24.3h after operation. Multivariate regression analysis associated age [P<0.001], cardiopulmonary bypass [P<0.001] and preoperative ductal dependency [P=0.04] with postoperative metabolic alkalosis. Of the surgical procedures the arterial switch for transposition of the great arteries [n=19] was strongly associated with metabolic alkalosis [100%, P<0.001]. Hemodilution appeared to enhance the development of alkalosis: those who experienced alkalosis had been hemodiluted to a greater extent [P=0.007]. Nearly 95% of patients experienced some increase in bicarbonate, but patients with metabolic alkalosis experienced more than those without [5.9 versus 3.5 mmol/l, P<0.001]. There were four postoperative deaths, only one coincidental with metabolic alkalosis.


CONCLUSIONS
Metabolic alkalosis has a high incidence after pediatric cardiac surgery, strongly associated with younger age, cardiopulmonary bypass, preoperative ductal dependency and perioperative hemodilution. Early recognition allows for timely therapeutic intervention.
van Thiel
Robert J
RJ
Department of Cardiothoracic Surgery, Thoraxcenter, Bd 156, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. r.vanthiel@erasmusmc.nl
Koopman
Sofie R
SR
Takkenberg
Johanna J M
JJ
Ten Harkel
Arend Derk Jan
AD
Bogers
Ad J J C
AJ
D000471:Alkalosis / Q000209:etiology* / Q000503:physiopathology; D001017:Aortic Coarctation / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D001639:Bicarbonates / Q000032:analysis; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002315:Cardiopulmonary Bypass / Q000379:methods; D006330:Heart Defects, Congenital / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D006343:Heart Septal Defects / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D006352:Heart Ventricles / Q000002:abnormalities / Q000601:surgery; D006400:Hematocrit; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011183:Postoperative Complications / Q000209:etiology*; D012189:Retrospective Studies; D013771:Tetralogy of Fallot / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D014188:Transposition of Great Vessels / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome
D001639:Bicarbonates