| Object:The aim of study is to investigate the effects of Phenylephrine and colloid for preventing hypotension on cardiac function during epidural anesthesia for cesarean section. To provide a new theoretical basis for the phenylephrine in obstetric anesthesia.Methods:we recruited 36 women of ASA physical status â… andâ…¡with term singleton pregnancies scheduled for elective cesarean delivery under epidural anesthesia. Patients with preexisting or pregnancy-induced hypertension, cardiovascular or cerebrovascular disease, known fetal abnormalities, or contraindications to epidural anesthesia were excluded. all patients aged between 20-40 years old and weight 53-85kg were randomly divided into two groups (18 cases in each group):colloid group (group 1) patients and Phenylephrine group (group 2) patients, it has been infused the preload capacity as a 500ml capacity to Group 1 within in 20 minutes, then followed according to 10ml*kg·h-1 maintenance infusion. Experimentally, by using 2% lidocaine 5ml through the epidural catheter we check the changes in the monitoring indicators, then we make sure the effect of anesthesia or the epidural catheter in the cavum epidurale, to give an additional amount of 2% lidocaine 10--15ml. Group 2 general was pumped Phenylephrine at 6μg*kg-1 h-1 after downward trend in blood pressure. According to blood pressure and other circulation indices changing, we control the speed of phenylephrine and the amount of colloid infusion. we recorded all of these following data:the systolic blood pressure (SBP), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke stroke volume (SV), thoracic fluid content (TFC), acceleration index (ACI), systemic vascular resistance (SVR) and the left ventricular acting (LW) in the following time respectively:5 minutes after entering the operating room (T1),5 minutes after testing dose (T2), at the time of skin incision (T3), the uterine incision (T4), the fetus removed (T5),5 minutes after fetus removed (T6),10 minutes after removal (T7) and surgical end (T8).Result:Two groups of patients with heart rate (HR) have different trends, group 1 patients gradually increased heart rate, heart rate in group 2 (HR) decreased in the T7T8 and has statistically significance(p<0.05). Cardiac output of two groups (CO) has statistically significance(p <0.05) from T5 to T8; Acceleration index (ACI) was significantly decreased slower in the group2 compared with the group 1 (in T3,T4,T6 P<0.05). Systemic Vascular resistance (SVR) also has statistically significance(p <0.05)in T2,T3,T5. More than two sets of data were not significantly different P> 0.05).Left ventricular doing work and myocardial oxygen consumption are closely related in two groups, at T4,T5,T7,T8 points P is less than 0.05, consistently.Conclusion:In obstetric anesthesia, although a large number of liquid effectively prevent expansion hypotension during spinal anesthesia, but significantly increased heart rate, cardiac output, increased the burden on the heart, cardiac work and myocardial oxygen consumption of the large increase. The use of phenylephrine in the treatment of hypotension during operation could maintain a good cycle stability and reducing cardiac work, reducing myocardial oxygen consumption, will be more beneficial to the heart. |
