Pathophysiology of Hypertrophic Pyloric Stenosis Revisited: The Use of Isotonic Fluid for Preoperative Infusion Therapy Is Supported

Abstract

Background: The aim of this study was to elucidate the preoperative clinical and biochemical profile of infants with IHPS to optimize infusion therapy. Patients and Method: We retrospectively analyzed data from 56 infants who were operated for IHPS. Our study includes growth and laboratory data prior to the initiation of therapy. Results: Median duration of propulsive vomiting was 4 d; the median age was 37 d (18 - 108), and the median body weight was 3840 g (2760 -5900). Metabolic alkalosis (MAlk) with a pH of 7.45 ± 0.06 and an stHCO3- of 28.7 ± 4.5 mmol/l was found. In a subgroup of the infants, negative base excess (BE) was observed. The sodium concentration was normal or reduced (mean/median of 137 mmol/l). There was a strong negative correlation between stHCO3- and K+. The carbon dioxide partial pressure tended to increase (5.72 ± 0.84 kPa). Calculations of osmolality revealed a normal osmolarity. Hypoglycemia did not occur. The creatinine clearance according to the Schwartz formula remained at a normal level (85.3 ± 24.3 ml/min/1.73 m2). Discussion: The presented case series is characterized by a short duration of preoperative vomiting. MAlk can be classified as a chloride deficiency syndrome. It is accompanied by normo- or hyponatremic dehydration with normal osmolality. Partial respiratory compensation occurred. A normal creatinine clearance indicated good glomerular renal function. Conclusion: The presented study supports the use of an isotonic infusion fluid with a low glucose concentration for preoperative infusion therapy.