Corrected to uncorrected? The metabolic conundrum of hypertrophic pyloric stenosis

Objectives The purpose of this study was to evaluate factors associated with repeat blood testing after establishment of normal metabolic parameters and factors associated with reversal of metabolic correction back an uncorrected form in preoperative management of infants with Hypertrophic Pyloric Stenosis (HSP). Methods A retrospective review of infants with HSP undergoing repeat serum chemistries after already having normal labs were identified. Variables associated with repeating normal bloodwork and reversion of normal to abnormal labs were identified. Associations between reversion to abnormal and ordering of repeat labs were determined. Results 255 cases were studied with a median of 2 lab tests drawn per patient (range 1–9). Of 142 serum chemistry tests repeated after a normal test, 27% became abnormal, most commonly hyperkalemia. 61% of these went to surgery. No variables were associated with a normal test becoming abnormal. However, a time lapse of > 12 h was associated with the reordering of bloodwork despite it already being normal. Conclusions There is little evidence to support need for repeat serum chemistry testing in cases of HPS once normality has been established. Development of clinical pathways to reduce the use of unnecessary serum testing may improve efficiency of patient care and limit unnecessary resource utilization. Level of evidence Retrospective Case control: 3b.