Comparison of preoperative to postoperative blood glucose in puppies undergoing elective surgical neutering

The objective of this study was to determine if overnight fasting is associated with hypoglycemia in puppies undergoing elective surgical neutering. One hundred seventy-one apparently healthy puppies between the age of 2 and 6 months presented for elective surgical neutering. Owners were instructed to withhold food from puppies after midnight the night before surgery; water was to be freely available. Blood samples were collected pre- and postoperatively to determine blood glucose, packed cell volume (PCV), and serum total protein (TP). Pre- and postoperative data were compared with a paired Wilcoxon test (paired samples). Hypoglycemia was defined as glucose < 4.2 mmol/L (76 mg/dL) for pediatric puppies ≤ 16 weeks of age (n = 116), and < 3.6 mmol/L (65 mg/dL) for juvenile puppies > 16 weeks of age (n = 55). Blood glucose significantly increased after surgery from median 8.8 mmol/L (interquartile range [IQR], 1.7 mmol/L; range, 4.9-12.3 mmol/L) to a median 9.7 mmol/L (IQR, 1.8 mmol/L; range, 5.4-14.7 mmol/L; P < 0.0001). Preoperative median PCV was 35% (IQR, 6.5%; range, 26-53%) and TP was 58 g/L (IQR, 6 g/L; range, 44-82 g/L). Preoperative values were significantly higher than postoperative values for PCV (median, 31%; IQR, 4%; range, 24-43%) and TP (median, 55 g/L; IQR, 7 g/L; range, 40-76 g/L; P < 0.0001). No puppy developed hypoglycemia and no adverse events were observed or reported. Overnight fasting did not result in pre- or postoperative hypoglycemia in studied puppies undergoing elective neutering.