A Comparative Study Of Infusion Of Ephedrine And Phenylephrine On Hemodynamic Stability After Spinal Anesthesia In Elderly Patients Undergoing Lower Limb Orthopaedic Surgeries

Abstract

AIM  To compare infusion of ephedrine and phenylephrine on hemodynamic stability after spinal anesthesia in elderly patients aged 60 years and above undergoing lower limb orthopedic surgeries. BACKGROUND • Patients aged 60 years and above undergoing lower limb orthopaedic surgeries commonly experience hypotension post spinal anesthesia • To overcome this effect and to maintain hemodynamic stability prophylactic infusion of vasopressors like ephedrine and phenylephrine are given METHODOLOGY Preliminaries: ● Written informed consent was taken. ● Nil per oral status was confirmed.  The patients were evaluated with a detailed history, general and systemic examinations in the preoperative room.  The airway, cardiovascular system and respiratory system were examined. Patients were divided into three groups, GROUP P (PHENYLEPHRINE), GROUP E (EPHEDRINE), and CONTROL GROUP. INTRAOPERATIVE  NIBP, electrocardiography, and pulse oximetry were applied to monitor PR, BP, and SpO2.  Insertion of 18G IV cannula and infusion of Ringer lactate solution 15ml/kg was administered.  The patients were positioned to sit. Using a 25 G Quincke spinal needle, a lumbar puncture was done at the L3–4 interface following skin disinfection and 2% lignocaine infiltration.  Premedication was given with Inj. Midazolam 0.5mg to alleviate anxiety of the patients.  The groups were administered intrathecally with Inj. BUPIVACAINE Heavy 15mg . Patients were turned to the supine position subsequently and Oxygen 5 L/min was delivered via a face mask.  The sensory level of blockade after spinal anesthesia was assessed by ice cubes or pinprick 5 mins after intrathecal injection.  GROUP P received a continuous infusion of 30ml 0.9% NaCl with 250 mcg phenylephrine for 30 mins after spinal anesthesia using a infusion syringe pump.  GROUP E received a continuous infusion of 30ml 0.9% NaCl with 30 mg of ephedrine for 30 mins after spinal anesthesia using a infusion syringe pump.  CONTROL GROUP were given an intravenous bolus of inj. mephentermine 6 mg after spinal anesthesia as and when required. The infusion of treatment medication in Group P and Group E was started immediately after spinal anesthesia. Non Invasive Blood pressure, heart rate, SpO2, ECG were monitored. Incidence of hypotension, bradycardia and the total dose of vasopressor used intraoperatively were noted. 15 minutes before the subarachnoid block and at intervals of 3, 6, 9, 12, 15, 20, 25, and 30 minutes following the subarachnoid block (spinal anesthesia) were used to record hemodynamic data. PROTOCOL FOR RESCUE TREATMENT; If SBP fall was greater than 30% from the baseline, bolus dose of Phenylephrine 50mcg/Ephedrine 5 mg was given according to the group. If heart rate was less than 50 beats per min Inj. Atropine 0.6 mg I/V was given. RESULTS - Age, sex , BMI and ASA Grades are comparable and are statistically insignificant. - The SBP was significantly higher in Group E when compared to other groups at all time intervals after spinal anaesthesia. - The DBP was significantly higher in Group E when compared to other groups at 3 mins, 6 mins, 9 mins, 12 mins, 15 mins and 25 mins time intervals after spinal anaesthesia - The MAP was significantly higher in Group E when compared to other groups at 3 mins, 6 mins, 15 mins and 20 mins time intervals after spinal anaesthesia. - The HR was significantly higher in Group E when compared to other groups and was significantly better at all time intervals after spinal anaesthesia. - The rescue doses were observed to be statistically insignificant. The rescue doses required in Ephedrine group was less when compared to phenylephrine and control group. - The number and percentage of Inj. ATROPINE given among all groups were observed to be statistically insignificant. The Inj. ATROPINE was required less in Ephedrine group compared to phenylephrine and control group.CONCLUSION The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were better maintained in the ephedrine group than phenylephrine and control group. The mean arterial pressure (MAP) was significantly higher in all groups but was more effective in ephedrine group. Heart rate was well maintained and prevention of bradycardia was effectively seen in ephedrine group compared to phenylephrine group.