Abstract

Background and Aim: Regional anaesthesia is usually preferred over general anaesthesia in parturients undergoing caesarian section. Hypotension during spinal anaesthesia for caesarean section is a common complication.

Here a study was designed to compare crystalloid preload and coload in parturients for caesarian section under subarachnoid block .

Material and Methods: 300 patients of age between 18-40yrs and weight 45-75Kg with ASA I/II Full term, singleton pregnancies undergoing elective caesarean section. Exclusion criteria includes any contraindication to spinal anaesthesia, diabetes, cardiovascular, cerebrovascular diseases, renal disorders, known fetal abnormalities.

This Prospective Randomized controlled study was conducted after institutional and ethics committee approval and written informed consent from patients recruited for the study were obtained. Preanaesthetic check done prior to surgery included physical examination and investigations as per requirement for the surgery. Tablet Ranitidine 150mg was administered orally the night before surgery. Inj. metoclopromide10 mg IV was given thirty minutes prior to surgery. All the patients had two intravenous cannulae, one for administration of fluid and the other for injecting drugs. On arrival in the operation room, non-invasive monitoring was instituted including ECG, NIBP and Spo2.  Baseline heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP)  was calculated as the mean of three  consecutive readings at 3min intervals during which the SBP did not vary by more than 10% from the average value. Patients were allocated into two groups randomly using computer generated random numbers. In Group P:n=150 (Preload) the patients received 15ml/kg of Ringer Lactate solution over a period of 15-20min before the subarachnoid block. Group C:n=150 (Coload)  patients received  15ml/kg of Ringer lactate solution using a pressurised infusion system as soon as CSF was tapped to administer fluid at the maximal possible rate over20min.All patients received 10-12 mg of 0.5% hyperbaric bupivacaine intrathecally in the sitting position in L3-4 intervertebral  space with 25 gauge Quinckes spinal needle. After the subarachnoid injection, the patients were made supine with a 15 degrees wedge under the right hip. The sensory level was assessed using pin prick using 25G needle every 5min till the level was stabilized for at least three consecutive readings.  After achieving a block height of T 4-5, the surgery was allowed to commence. The following parameters were recorded every 2 minutes after the spinal injection till the first 10min, every 5min till the next 20min and every 10 min thereafter till the end of surgery: heart rate, systolic, diastolic, mean arterial pressures and Spo2.The values obtained in the first 60 minutes were used for statistical analysis. Maternal hypotension was defined as a systolic blood pressure < 20% of calculated baseline value . Hypotension was treated with additional rapid bolus infusion (approximately 100ml) of lactated Ringer solution. If not responsive, 6mg intravenous bolus of ephedrine to maintain systolic blood pressure at baseline value. In the event of excessive blood loss (>800ml as assessed by volume in suction bottle and weighing of swabs), the patient was excluded from study and treated appropriately. Bradycardia was defined as a heart rate <50beats/min and treated with atropine 0.6mg. After delivery of the baby,the mother was given infusion of 20U of pitocin in normal saline as routine practice. The person charting the hemodynamic parameters was not involved in the study and was unaware whether the patient had been pre-loaded or co-loaded. The number of doses of ephedrine required to treat hypotension was recorded. The total volume of fluid received by the patient during the duration of surgery was assessed. The attending neonatologist determined the APGAR scores of the baby at 1min and 5min after delivery."After data collection, data analysis is done with the help of SPSS software Ver 15 and Sigma Plot Ver 12.Quantitative data is presented with the help of Mean & Standard Deviation, comparison between the study groups is done with the help of Unpaired T test. Qualitative data is presented with the help of Frequency and Percentage table, association among study group is assessed with Chi-Square test (Fisher Exact test is applied for 2*2 table).P Value <0.05 is taken as significant.

Result: The incidence of hypotension, extra fluid boluses and number of ephedrine doses administered was higher in preload than coload group and difference was statistically significant.

The neonatal APGAR score, the mean heart rate in both preload group & co-load was statistically insignificant.

Conclusion: Crystalloidcoload is more efficient than crystalloid preload in prevention of hypotension in caesarean section following spinal anaesthesia.

Keywords: Crystalloid , coload, preload, Hypotension, subarachnoid block