Comparative evaluation of spinal anesthesia between 0.5% Levobupivacaine and 0.5% Ropivacaine for open hernia surgeries -A Randomized Prospective Study

Introduction:

Spinal anaesthesia is routinely used for lower umblical procedures.Bupivacaine 0.5%heavy is routinely used .Recently levobupivacaine is introduced .it has more cardio stability.I  BETWEEN n this study we are comparing spinal anaesthesia effect isobaric 0.5% Levobupivacaine  and isobaric 0.5% Ropivacaine

Aim:

To compare the clinical effect and quality of spinal isobaric 0.5% Levobupivacaine  and isobaric 0.5% Ropivacaine for elective open hernia surgeries

Primary objective

To compare the time of onset of sensory block,

To compare the time to peak sensory block

To observe the differences in the duration of sensory block

To determine the duration of analgesia

Secondary objective

To observe and compare the hemodynamic instability

To identify the complications developing if any

CENTRE                :               Stanley medical college hospital, Chennai

DURATION          :               6 months

DESIGN                :               A Randomised , Prospective study

POPULATION     :               Patients coming for Elective open hernia                                                                                              surgeries

SAMPLE SIZE      :               50

Based on the reference study done by Samar et al, Mumbai

Formula:

n = 2 (Za+ZB)2 SD2 / (M1-M2)2

Where Za = 1.96 (statistical significant constant for 95% CI) , ZB = 0.84 (80% power)

Sd = 1.82 (Standard deviation of onset of sensory block in minutes among patients belonging to levobupivacaine group from previous study. )

M1 =8.47 (Mean onset of sensory block in minutes among patients belonging to ropivacaine group from previous study.M2 = 6.97 (Mean onset of sensory block in minutes among patients belonging to levobupivacaine group from previous study.)

(M1-M2)2 = 2.25 (1.5 x 1.5)On substituting in the formula.n = 15.6 x 1.8 x 1.8 / 2.25 ;n = 22

Adding 10% non response rate (ie 10% of 22= 2)n = 24 (minimum sample size).Therefore Sample size n = 25 (1 group)    n = 50 (2 groups).

Methodology:

After ethical committee clearance and getting informed written consent fifty patients will be equally divided into two groups INCLUSION CRITERIA

•       American society of anaesthesiologist physical status I & II

Age between 20 – 60 years

Posted for elective open hernia surgery

Patients willing to participate

EXCLUSION CRITERIA

American society of anaesthesiologist physical status III & IV

Coagulation Abnormalities

Localised Infections

Severe renal,hepatic,& cardiovascular diseases

Patients not willing for spinal anaesthesia

Group A: Contains 25 patients will receive spinal anaesthesia with 2.0 ml 0.5 % Levobupivacaine

Group B: Contains 25 patients will receive spinal anaesthesia with 2.0 ml 0.5 % Ropivacaine

Randomization will be done using computer generated random numbers and allocation will be done using sealed envelope technique. Intravenous line will be secured and crystalloids connected.standars monitors like pulse oximeter,Non invasive blood pressure  and Electro cardio gram will be connected. Sub arachnoid block will be given using quincke needle at L3-4 level with patient in sitting position. Patient, investigator and statistician will be blinded to the study drug as drug will be prepared by an anaesthesiologists who is not involved in the study.

Heart rate,systolic and diastolic blood pressure and saturation will be monitored every 3miutes for first 10minutes then every 15 minutes till the end of the surgery

Sensory block – pin prick test, 24g hypodermic needle – every 3 minutes initial 15 minutes then every 20 minutes

T10- L1 – surgical dermatome

Time of onset, time to achieve peak sensory level, duration of analgesiaHypotension, bradycardia, vomiting, desaturation, difficulty in breathing – appropriately managed

Level inadequate/ breakthrough pain / prolonged surgical time – GA given

Statisytical analysis: descriptive analysis of the data will be done .mean and standard deviation will be compared using student t test for normally distributed continuous variable and chi square test for discrete variable