Myocardial function and hemoglobin oxygen affinity during hyperglycemia in the fetal lamb.

Abstract

To determine the effects of maternal hyperglycemia on fetal hemodynamic and cardiac function, a study was carried out on nine chronically catheterized fetal sheep. In six fetuses, glucose was infused intravenously with an initial dose of 5 mg/kg per min. Data were compared with controls. This dose was gradually increased to 16 mg/kg per min by the fifth day. The initial blood glucose was 14.7±3.0 mg/dl and increased to 54.6±16.4 mg/dl by the last day of the infusion period (P < 0.001). The P02 decreased from a baseline of 20.25±3.40 to 15.88±5.24 mmHg (P < 0.01). Similarly significant decreases were also observed for the blood 02 content and 02 hemoglobin saturation: 8.5±1.7 to 6.4±2.2 ml/dl and 62.3±13.6 to 46.1±17.6%, respectively, during hyperglycemia (P < 0.01). The duration of the preejection period (PEP) before the start of the experiment was 45±4 ms; a final value of 57±10 ms was obtained (P < 0.01). However, the electromechanical delay and ejection time (ET) showed no significant variation. The ratio of the PEP/ET increased from 0.31±0.04 to 0.38±0.07 (P < 0.01) during hyperglycemia. The reticulocytes increased from 1.4±1.8 to 3.1±2.9% (P < 0.05) and the 2,3-diphosphoglycerate decreased from 4.4±1.1 to 2.8±1.2 ,mol/g hemoglobin (P < 0.005). This study demonstrated that fetal hyperglycemia depresses myocardial function in the fetal lamb. The changes in cardiac function could not be explained by the small drop in 02 saturation.

Altered diastolic function in infants of mothers with gestational diabetes: No relation to macrosomia

“…Animal studies have demonstrated that a combination of hyperglycemia and hyperinsulinemia can lead to moderate hypoxia and depressed myocardial function [1,8,13]. Fetal hyperinsulinemia [4] alone may lead to macrosomia and cardiac hypertrophy.…”

“…Therefore, in the present study we have reanalyzed the data to determine the influence of the size of infant on various cardiac parameters by comparing: (1) LGA infants of GDMs and controls; (2) appropriate-for-gestational-age (AGA) infants of GDMs and controls; and (3) LGA infants with AGA infants of GDMs and controls. Our data suggest that altered cardiac function in IGDMs was not related to macrosomia but was a consequence of maternal diabetes.…”

Effect of the 100‐g oral glucose tolerance test on fetal acid–base balance

“…Fetal hypoxia and acidosis were also observed in the studies of Richardson et al (1983), Crandell et al (1985) and Smith and Lumbers (1987). Bard et al (1986) evaluated the effect of maternal hyperglycemia on fetal hemodynamic and cardiac function in a sheep model. Their main finding was that fetal hyperglycemia depressed myocardial function in the fetal lamb.…”

Cardiovascular Status during Ketamine Anesthesia in the Fetal Lamb

“…The fetuses were then instrumented according to a protocol previously described [11], After a recupera tion period of 4 days, control data were collected dur ing 24 h. Then each ewe received intravenously a priming dose of ketamine hydrochloride of 5 mg/kg followed by a maintenance dose (2 mg/kg) every 15 min during 1 h. Finally, a recovery phase was planned during which the animals were studied 1 and 24 h after the last ketamine injection. Artificial venti lation was never used during the anesthesia.…”