GOYAL, Indian J.RAMAKRISHNA, Anaesth. 2006; 50BHANDARKAR (3) : 183 - 186 : ISOFLURANE & HALOTHANE IN DAY CARE SURGERY : COMPARISON
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CLINICAL INVESTIGATION
A COMPARATIVE EVALUATION OF THE CHARACTERISTICS OF RECOVERY FROM ANAESTHESIA WITH ISOFLURANE AND HALOTHANE IN DAY - CARE SURGERY Dr. Navdeep Goyal1
Dr. B. Ramakrishna2 Dr. Sudha Bhandarkar3
SUMMARY In India, Halothane and Isoflurane are the two most frequently and widely used inhalational agents. So in this study we endeavored to compare the recovery profile of halothane and isoflurane in day-care surgery using these freely available agents. A prospective study of 60 adult patient, ASA Gr-I and Gr-II under going different surgical procedures of short duration up to half an hour was taken up, after proper preoperative screening of patients at our institution. Induction of anaesthesia was done with intravenous propofol 2 mgkg-1 and maintained using either 1.5MAC Halothane or 1.5MAC Isoflurane. We have avoided narcotic analgesics and anti sialogogue such as atropine that cross blood brain barrier which may interfere with the recovery patterns. Post-op recovery was judged by various clinical tests and divided into early, intermediate, and late. We found that early recovery following Isoflurane was more rapid compared to Halothane. The results of the psychomotor tests to assess the intermediate recovery also showed the significant difference between the two groups. More number of patients were able to sit up at half an hour and stand at two hours in the isoflurane group compared to halothane group. The study concluded that isoflurane is a useful and better anaesthetic over halothane and offers a clear advantage when used for maintenance of anaesthesia for operations of short duration performed on a day-care basis.
Keywords : Halothane, Isoflurane, Recovery, Day-care surgery. Introduction In the early 1900‘s, an American anaesthesiologist, Ralph Waters, opened an outpatient anaesthesia clinic in Sioux City, Iowa; which provided care for dental and minor surgical procedures and is generally regarded as the prototype for the modern freestanding ambulatory surgical center.1 A safe and short postoperative recovery period and especially the full recovery of complex psychological function after general anaesthesia have become increasingly important. Most of the published studies relate to comparison of halothane or isoflurane to sevoflurane, desflurane or enflurane in pediatric surgeries,2,3,4,5 dentistry and oral surgeries6 or in animals.7,8 In the present study between isoflurane and halothane, we investigated the comparative profile of recovery including emergence time, psychomotor recovery, ability to sit and stand unsupported in general out-patient surgical patients. The assessment of patient’s recovery after ambulatory surgery is conveniently divided into early, 1. DNB., Resident 2. M.D, D.A, Chief anaesthesiologist 3. D.A, Consultant anaesthesiologist Department of Anaesthesiology and Critical Care Medwin Hospital, Hyderabad-500001, India. Correspond to : Dr. Navdeep Goyal Room no. G-12, 4th floor, Medwin hospitals, Nampally. Hyderabad-500 001, Andhra Pradesh, India. E-mail :
[email protected] (Accepted for publication on 31 - 3 - 2006 )
intermediate and late recovery. Early recovery is the time from which the operation is completed and anaesthetic is turned-off until the patient is awake and oriented. Intermediate recovery is the period between admission and discharge from the post-anaesthesia care unit. The patient is home ready at the end of intermediate recovery. Late recovery starts when patient return home and continue until full functional recovery is achieved. At the time of intermediate recovery the patient should have minimal pain and be able to walk. The choices of anaesthetic technique as well as postoperative analgesic and antiemetic drugs have a major impact on duration of intermediate recovery. There are many tests that are used for studying psychomotor recovery and some have been shown to be reliable and useful in terms of both accuracy and objectivity. No single test can be said to be a golden standard partly because many tests measure different aspects of perception, cognition, memory or motor skills. Our study not only includes the commonly used and most reliable tests such as Perceptive accuracy test, choice reaction time but also other tests such as peg-board test, card sorting test, finger tapping and Trieger dot test which cover the different aspects of psychomotor recovery. Methods A prospective clinical study was carried out in sixty ASA Gr-I and Gr-II patients to compare the recovery characteristics. Pre operative investigations were done in accordance with Roizen’s guidelines.9 NPO orders were
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given as follows. All patients were instructed for a restriction of solids for 8 hrs and oral clear fluids were allowed for upto 2 hrs. before surgery. (Patients accustomed to taking early morning bed tea were allowed that). Patients were premedicated with oral 0.5 mg alprazolam night before surgery. To maintain a protocol all patients were given 150 mg of ranitidine P.O. and 10 mg of metoclopramide P.O. one hour before surgery as aspiration prophylaxis and to reduce PONV. Intramuscular diclofenac 75 mg half-anhour before induction of anaesthesia was also given as premedication. After pre-medication, the patient was wheeled into operating room and transferred onto operating table. After recording the vital parameters, an intravenous line was secured and connected to a slow 0.9% normal saline drip. Glycopyrrolate 0.2 mg I.V. was given. Patient was induced with 1% propofol 2 mgkg-1; slowly i.e every 4 ml in 10 seconds until the eyelash reflex was obtunded. On abolition of eyelash reflex patient was maintained on spontaneous ventilation by using Magill’s circuit with N2O 6 Lts; O2 3 Ltrs. and isoflurane 1.5 % in group – I or halothane 1.5 % in group – II patients. Intraoperative pulse rate, blood pressure and oxygen saturation were vigilantly observed. At the conclusion of surgery, recovery from anaesthesia was judged on the basis of the following criteria: Asking the patient every one minute till he opens his eyes on command and gives his name, date of birth or date of marriage. The intermediate recovery was tested every 15 minutes by the following psychomotor tests:
INDIAN JOURNAL OF ANAESTHESIA, JUNE 2006
The percentage of correct performances and time taken to fix the pegs are recorded. 5. Card sorting test A set (i.e. 52) of playing cards is taken. Patient is asked to separate red and black cards into two bundles. The time taken to separate the total cards is recorded. 6. Trigger dot test A map of flower with 90 dots was given to each patient is asked to unite the dots and draw the map. The percentage of missing dots out of total dots was recorded. Along with the psychomotor tests clinical parameters i.e. pulse rate, blood pressure, oxygen saturation and respiratory rate were checked at regular intervals. All throughout operation and in the post operative period vigilant observation was kept to notice any of the complications or undesired events like nausea, vomiting, hiccups, apnea, cyanosis and dys as rhythmias. The patients were given fitness for discharge or “Home Readiness” by senior anaesthesiologist after 6 hours using pre set criteria. Statistical analysis The data obtained finally was statistically analyzed by using analysis of variance (ANOVA) and P value less than 0.05 was considered significant. Ethics
1. Choice reaction time Four different coloured bulbs with corresponding coloured switches were fixed on a wooden board. After switching on a coloured light, patient is asked to switch off the light by using the corresponding coloured switch. The median time of 20 stimuli is taken as the choice reaction time.
This study was conducted in sixty patients (thirty patients in group – I and thirty patients in group – II) after taking institutional approval for day-care surgery and patients were chosen from our hospital. Informed consent was taken from all the patients being enrolled for study and all the patients were explained all the clinical tests that will follow the surgery.
2. Perceptive accuracy test Patients is asked to tell the two or three digits number displayed on a calculator. The number of correct answers in a period of two minutes is accorded.
Results Early recovery from anaesthesia was judged by asking the patient to open the eyes and give his or her date of birth or date of marriage. This was done at intervals of every one-minute after discontinuing the inhalational anaesthetic isoflurane or halothane. There was a significant difference between the two groups. The difference in the means between the two groups for opening the eyes on command was 4 minutes 48 seconds with 95% Confidence Interval (CI) of 4 minutes 15 seconds to 5 minutes 20 seconds. This CI for giving date of birth was again 4 minutes 13 seconds to 5 minutes 23 seconds, the mean difference being 4 minutes 48 seconds. The isoflurane group responded earlier than halothane group. Doing the
3. Finger tapping test The patient is asked to tap on the keyboard of the calculator. The number of times the patient taps on the keyboard in a 30 seconds period is taken as the finger tap score. 4. Peg board test A board with the space to fix the pegs was taken. Patient is asked to fix all the peg in their correct places.
GOYAL, RAMAKRISHNA, BHANDARKAR : ISOFLURANE & HALOTHANE IN DAY CARE SURGERY : COMPARISON
psychomotor tests at the intervals of every 15 minutes assessed the intermediate recovery. Patients of both groups could not perform these tests at 15 min but could perform at 30 minutes. There was significant difference between the two groups in the abilities to sit at 30 minutes and to stand at 120 minutes. The higher percentage of patient were able to sit at 30 min and stand at 120 min with isoflurane than with halothane. 20% (95% CI of 0% to 40%) more patients in the isoflurane group were able to open eyes on command at 30 minutes. Also 23% (95% CI 0% to 45%) more in this group were able to stand unsupported at 60-120 minutes. At 120 min the number of cases that were ready for discharge from recovery room were more in the isoflurane group than in the Halothane group. At 180 min all the cases in both groups were able to stand and walk without support. No incidence of Nausea, Vomiting, apnea, cyanosis, and hiccups were noted in both groups. On enquiry none of the patients had awareness during surgery. Table - 1 : The average response time. Opening eyes on command
Giving date of birth
Group – I isoflurane mean (SD)
4 min 42 sec. (48 sec.)
5 min 42 sec. (52 sec.)
Group - II halothane Mean (SD)
9 min 30 sec. (1min. 5 sec.)
10 min 30 sec. (1min. 20 sec.)
Difference between two means
4 min. 48 sec. P < 0.05
4 min. 48 sec. P < 0.05
95% CI for difference between two means (for opening eyes) 4 min. 15 sec. to 5 min. 20 sec. (for telling date of birth) 4 min. 13 sec. to 5 min. 23 sec.
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Table – 3 : Ability to stand and walk without support.
Ability to sit up At 30 min. At 30-60 min
Ability to stand unsupported At 60-120 min. At 120-180 min.
Isoflurane Group-I Percentage of patients
Halothane Group-II Percentage of patients
P – value
95% CI for difference in proportions
87% 13% all remaining
67% 33% all remaining
