oxytocin and Hypertension--Pulmonary

Haemodynamic changes that occur during pregnancy are maximal between 28 and 34 weeks. In the pregnant woman with several associated diseases, such as hypertensive myocardiopathy and pre-gestational diabetes, these changes can lead to a difficult control of pulmonary hypertension and acute pulmonary oedema. We report the case of a pregnant woman with long term type 1 diabetes mellitus who suffered pre-eclampsia in a previous pregnancy, and since then developed hypertensive cardiomyopathy. She was admitted at 30 week gestation for metabolic and blood pressure control, and developed congestive cardiac failure after the administration of betamethasone for foetal lung maturity. A transthoracic echocardiogram showed a non-dilated hypertrophic left ventricle with good systolic function, restrictive diastolic dysfunction and moderate pulmonary arterial hypertension. When her general condition improved, we performed a caesarean section under regional anaesthesia to prevent the complications of pulmonary and systemic hypertension. We present the anaesthetic management and resolution of complications after oxytocin administration.

Topics: Adult; Anesthesia, Epidural; Anesthesia, Obstetrical; Betamethasone; Cardiomyopathy, Hypertrophic; Cardiovascular Agents; Cesarean Section, Repeat; Diabetes Mellitus, Type 1; Diastole; Female; Heart Failure; Humans; Hypertension, Pulmonary; Hypotension; Infant, Newborn; Intraoperative Complications; Norepinephrine; Oxytocin; Phenylephrine; Pre-Eclampsia; Preanesthetic Medication; Pregnancy; Pregnancy Complications, Cardiovascular; Pregnancy in Diabetics; Supine Position

pulmonary hypertension (PH) in the rat leads to right ventricular (RV) hypertrophy, inflammation and increased natriuretic peptide (NP) levels in plasma and RV. Because the release of nitric oxide (NO) and atrial natriuretic peptide (ANP) is a function of the oxytocin receptor (OTR), we examined the effect of PH on gene and protein expression of OTR, NP (A, atrial; B, brain) and receptors (NPRs), nitric oxide synthases (NOS), interleukin (IL)-1β, IL-6 and tumour necrosis factor-α in the hypertrophied RV in a model of PH.. RV hypertrophy was induced in male Sprague-Dawley rats with monocrotaline (MCT; 60 mg kg(-1) ) and was confirmed by the presence of an increased RV weight and RV-to-[left ventricle (LV) and septum] ratio.. in the RV of MCT-treated rats, a approximately 40% reduction in OTR mRNA and protein was observed compared with the RV of control rats. This reduction was associated with increased transcripts of ANP and BNP in both ventricles and a corresponding increase in NP receptor mRNA expression for receptors A, B and C. Protein expression of inducible NOS was increased in the RV, whereas endothelial NOS transcripts were increased only in the LV of MCT-treated rats. In the RV of MCT-treated rats, downregulation of OTR was also associated with increased mRNA expression of IL-1β and IL-6.. our results show that downregulation of the OTR in the RV of MCT-treated rats is associated with increased expression of NP and their receptors as well as IL-1β and IL-6. This reduction in OTR in RV myocardium may have an impact on cardiac function in the MCT-induced model of PH.

Topics: Animals; Blotting, Western; Down-Regulation; Gene Expression; Heart Ventricles; Hypertension, Pulmonary; Male; Monocrotaline; Oxytocin; Rats; Rats, Sprague-Dawley; Receptors, Oxytocin; Reverse Transcriptase Polymerase Chain Reaction

The haemodynamic effects of oxytocin on the pulmonary and systemic circulation were studied in six awake, pregnant (greater than 140 days gestation) ewes. Bolus doses of oxytocin 0.2 units/kg and then 0.8 units/kg were administered. A dose of 0.2 units/kg resulted in small but significant increases in mean pulmonary artery pressure (14%, P less than 0.05) and pulmonary vascular resistance (24%, P less than 0.05. A bolus of 0.8 units/kg resulted in a significant increase in mean arterial pressure (20%, P less than 0.05) and systemic vascular resistance (33%, P less than 0.05). Acute pulmonary hypertension was then induced with glass bead microemboli (150-200 microns), with an increase in pulmonary artery pressure of 26 mmHg and pulmonary vascular resistance of 448 dyn. s. cm-5. Boluses of oxytocin 0.2 and 0.8 units/kg were then administered. There were no significant changes, except for a 30% increase in systemic vascular resistance at one minute after oxytocin, 0.8 units/kg (P less than 0.05).

Topics: Animals; Atrial Function, Right; Blood Circulation; Blood Pressure; Cardiac Output; Female; Hypertension, Pulmonary; Oxytocin; Pregnancy; Pregnancy, Animal; Pressure; Pulmonary Artery; Pulmonary Circulation; Pulmonary Wedge Pressure; Sheep; Uterus; Vascular Resistance