SAT0586 PREVALENCE AND RISK FACTORS FOR CARDIO-METABOLIC ABNORMALITIES IN PATIENTS WITH INFLAMMATORY ARTHRITIS ATTENDING CARDIO-RHEUMATOLOGY PRIMARY PREVENTION CLINICS

Abstract

OBJECTIVE Oxytocin is widely used to prevent postpartum hemorrhage at the time of Cesarean delivery. This drug is known to have both vasodilatory and vasoconstrictive effects in different human blood vessels. Administration of high dose intravenous oxytocin (5 and 10 IU) has recently been shown to cause ST depression in the human myocardium with possible cardiac ischemia. The effects of a similar dose on maternal cerebral hemodynamics are unknown. Therefore, we aimed to determine the effect of a 5 IU oxytocin IV bolus on maternal middle cerebral artery (MCA) hemodynamics. STUDY DESIGN Prospective observational study. MCA velocity profi les were measured using transcranial Doppler (TCD) in 6 healthy, normotensive women scheduled for an elective Cesarean delivery. Blood pressure (BP) was recorded at the time of TCD measurement. Measurements were performed at baseline and again at 2 and 5 minutes following the oxytocin bolus. At each TCD measurement systolic, diastolic and mean velocities were recorded. Resistance index (RI), pulsatility index (PI), cerebral perfusion pressure (CPP), resistance area product (RAP) and cerebral fl ow index (CFI) were calculated. RESULTS A signifi cant decrease in BP was noted 5 minutes after infusion, whereas the cerebral effects were seen after only 2 minutes: systolic velocity, RI and PI increased signifi cantly and to above expected limits for gestational age. CPP and CFI values decreased signifi cantly after 2 minutes and RAP after 5 minutes. The shape of the MCA velocity waveform also changed signifi cantly suggesting an increased resistance profi le. CONCLUSIONS: Oxytocin as a 5 IU bolus decreases cerebral perfusion and fl ow index within minutes of administration, and increases RI and PI. This is consistent with cerebral vasoconstriction due to a direct effect on smaller arteries and arterioles in the brain. Further studies are needed to determine the relationship and clinical effects of these changes in women with impaired autoregulation, including those with hypertensive disorders of pregnancy.