Evaluating the efficacy of inj.metoprolol 50μgm./kg.i.v., in attenuating Hemodynamic response to laryngoscopy, intubation and Carbon Dioxide Pneumoperitoneum in Patients Undergoing Laparoscopic Appendicectomy

Madhavakrishna, N V (2009) Evaluating the efficacy of inj.metoprolol 50μgm./kg.i.v., in attenuating Hemodynamic response to laryngoscopy, intubation and Carbon Dioxide Pneumoperitoneum in Patients Undergoing Laparoscopic Appendicectomy. Masters thesis, Stanley Medical College, Chennai.

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Abstract

INTRODUCTION: Laryngoscopy and intubation cause a marked increase in adrenergic activity due to stress response. The resulting tachycardia, hypertension and arrhythmias may cause hemodynamic instability in patients with cardiovascular disease. Laparoscopic procedures for both diagnostic and surgical purposes are becoming increasingly popular. They offer specific advantages to the patient like, less post operative pain, less severe respiratory dysfunction and quicker recovery, less tissue damage and inflammation, nitrogen balance and immune function are better preserved5, shorter hospital stay, early ambulation, less morbidity and smaller scars. Carbon dioxide pneumoperitoneum produced during these procedures causes similar hemodynamic changes as in airway manipulation. This may be due to, Increased intra abdominal pressure, Neurohumeral responses and Absorbed carbon dioxide leading to hypercarbia Much of the initiation of the stress response relies on the outflow of the sympathetic neuronal pathway. Many pharmacological techniques using adrenoreceptor blockers, calcium channel blockers, opioids, vasodilators were used to attenuate these responses, which indicates lack of an ideal drug for this purpose. Metoprolol, a selective β1 adrenergic blocking agent acts by, competitive antagonism of catecholamines at peripheral (especially cardiac) adrenergic neuron sites, leading to decreased blood pressure; Central effect leading to reduced sympathetic outflow to the periphery; Suppression of renin activity. These properties of metoprolol make it suitable for suppressing the stress response. Moreover, the elimination halftime of Metoprolol43 being 3.5 hours allows it to be administered as a single dose covering the duration of surgery. Thus in this study we are evaluating the efficacy of injection metoprolol 50 micrograms/kg. i.v., in attenuating these stress responses. AIM OF THE STUDY: 1. To study the efficacy of Inj.Metoprolol 50 micrograms/kg i.v. given 5 minutes before induction of anesthesia in attenuating hemodynamic stress response to laryngoscopy, intubation and carbon dioxide pneumoperitoneum in laparoscopic appendicectomies. 2. To observe for any complications related to inj.Metoprolol during intra operative period and 8 hours postoperatively. MATERIALS AND METHODS: After obtaining hospital ethical committee approval 60 consenting ASA Class 1 patients , with airway Mallampatti classification 1& 2, in the age group of 15 to 45 undergoing laparoscopic appendicectomy were selected for the study. Study design: prospective randomized double blind controlled study. Randomization done using a set of computer generated random numbers. The anaesthesia provider and the observer were blinded. Another person other than the anesthesia provider and the observer loaded either inj. Metoprolol or normal saline as per the random numbers and gave it to the anesthesia provider. The syringes were labeled only with the serial no. assigned to the patient Preoperative Assessment: Thorough pre operative assessment with medical history, physical examination and investigations carried out in all these 60 patients, Hb%, Total count, differential count, Renal function tests, Blood glucose, Blood grouping, Bleeding time and Clotting time, ECG, Chest X ray. Exclusion Criteria: 1. Hypertension, 2. Ischemic heart disease, 3. Diabetes mellitus, 4. COPD, Bronchial Asthma, 5. ECG: rhythm other than sinus, any degree of heart block, 6. more than 1 attempt at intubation, 7. peripheral vascular disease, 8. Patients who were converted to open surgery after laparoscopic visualization. All the 60 patients were given Tablet Alprazolam 0.25mg, Cap.Omeprazole 20mg, Tablet Ondoncetron 4 mg night before surgery. SUMMARY: Aim of this study is to evaluate the efficacy of inj.Metoprolol 50 mic.gms/kg. i.v. given 5 minutes before induction of anesthesia in attenuating the hemodynamic response to intubation and carbon dioxide pneumoperitoneum and to look for any adverse effects. There was no significant difference between the Metoprolol group and Control group in respect to age, sex distribution, weight, Airway class, duration of laryngoscopy and pneumoperitoneum. After 1 and 5 minutes after intubation, there was no significant increase in heart rate compared to basal heart rate in both the group. Our anesthetic technique was sufficient to blunt the heart rate response to intubation in the control group. But there was significant increase in Mean Arterial Pressure in Control group from basal readings during both 1 and 5 minutes after intubation. In Metoprolol group there was a small but significant decrease in Mean Arterial Pressure 1 minute after intubation, and no significant change 5 minutes after intubation. During CO2 Pneumoperitoneum there was a significant increase in Heart Rate and Mean Arterial pressure in Control group 15 minutes after pneumoperitoneum compared to both basal and pre pneumoperitoneum values. But in Metoprolol group there was no significant difference in Heart Rate and Mean Arterial Pressure compared to basal and pre pneumoperitoneum values. There was no significant difference in Heart Rate and Mean Arterial Pressure recordings at 15,30,45 minutes after pneumoperitoneum in both the groups. Similarly, there was a significant increase in Heart Rate and Mean Arterial Pressure in Control group after extubation compared to the pre extubation readings. But there was no significant difference in Heart Rate and Mean Arterial Pressure between pre extubation and after extubation recordings in Metoprolol group. Moreover, there was significantly more urine output after 1 hour of induction of anesthesia in Metoprolol group compared to Control group. In Metoprolol group two patients had hypertensive episodes and they were controlled with additional fentanyl supplementation. In Control group ten patients developed hypertensive episodes all of them were given additional fentanyl. In addition to fentanyl 5 of them required additional increase in Isoflurane inspiredconcentrations to control the increase in blood pressure. One patient in the Metoprolol group and two in the Control group had hypotensive episodes, and they were managed with fluid boluses. None required vasopressors. Two patients in both the groups developed sinus bradycardia, Three of them did not require any treatment, one in the Metoprolol group was treated with inj. Atropine 0.6mg i.v. Three patients in Metoprolol group and four patients in Control group had mild postoperative nausea and vomiting. Many studies have demonstrated similar efficacy with other ß blockers like propranolol and esmolol,Metoprolol scores over propranolol in being cardioselective so that it can be used in situations where propranolol is contra indicated. The disadvantage with esmolol is, it has to be repeated or an infusion has to be maintained because of its ultra short duration of action, whereas a single dose of Metoprolol is effective for the entire duration of surgery. CONCLUSION: 1. Inj.Metoprolol 5μgm./kg. i.v. given 5 minutes before induction of anesthesia effectively attenuates the hemodynamic response to laryngoscopy, intubation and carbon dioxide pneumoperitoneum. 2. There were no significant complications associated with inj.Metoprolol 50μgm./kg/i.v during intraoperative period and 8 hours postoperatively.

Item Type: Thesis (Masters)
Uncontrolled Keywords: inj.metoprolol 50μgm./kg.i.v. ; attenuating Hemodynamic response ; laryngoscopy ; intubation ; Carbon Dioxide Pneumoperitoneum ; Patients ; Undergoing Laparoscopic Appendicectomy.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Subramani R
Date Deposited: 22 Apr 2018 15:55
Last Modified: 28 Apr 2018 06:44
URI: http://repository-tnmgrmu.ac.in/id/eprint/7240

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