Fetal cardiovascular response to acute hypoxia during maternal anesthesia

Preclinical imaging studies of fetal haemodynamics require anaesthesia to immobilise the animal. In the presence of isoflurane, isoflurane/ketamine and ketamine/midazolam, but not propofol anaesthesia, maternal and fetal hypoxaemia increased fetal mean arterial pressure and decreased peripheral blood flow. Acute fetal hypoxaemia induced fetal tachycardia regardless of anaesthetic type. These results have implications for the design and interpretation of preclinical imaging studies where anaesthesia is required. AbstractPreclinical imaging studies of fetal hemodynamics require anesthesia to immobilize the animal. This may induce cardiovascular depression and confound measures under investigation. We compared the impact of four anesthetic regimes upon maternal and fetal blood gas and hemodynamics during baseline periods of normoxia, and in response to an acute hypoxic challenge in pregnant sheep. Merino ewes were surgically prepared with maternal and fetal vascular catheters and a fetal femoral artery flow probe at 105 –109 days gestation. At 110–120 days gestation, ewes were anesthetized with either isoflurane (1.6%), isoflurane (0.8%) plus ketamine (3.6 mg·kg−1·h−1), ketamine (12.6  mg·kg−1·h−1) plus midazolam (0.78  mg·kg−1·h−1), propofol (30  mg·kg−1·h−1), or remained conscious. Following 60  min of baseline recording, nitrogen was administered directly into the maternal trachea to displace oxygen and induce maternal and thus fetal hypoxem...
Source: Physiological Reports - Category: Physiology Authors: Tags: ORIGINAL RESEARCH Source Type: research