الفهرس 
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Abstract
The inclusion of an opioid as a component in balanced anesthesia offers several advantages; the course of anesthesia tend to be associated with less fluctuation in cardiovascular dynamics, decreases requirements of inhaled anesthetics, reducing their side effects, toxicity and provides
increase postoperative analgesia (Hecker et at, 1983).
Hypertension, tachycardia and arrhythmia are well documented reflex cardiovascular effects of laryngoscopy and tracheal intubation (Maekawa et at, 1993) as well as tracheal extubation (Hartley and Vaughan, 1993). These cardiovascular responses, although transient, may be harmful in some patients particularly those suffering from myocardial or cerebrovascular disease. The use of opioids is one of the many techniques that have been done to reduce the extent of the response.
Stress and postoperative outcome may be linked closely in patients undergoing major surgery. Many comparative clinical trials have shown a great incidence of postoperative complication as a result of increased hormonal and metabolic responses to surgery (Yeager et at, 1987 and Roizen et at, 1987). Anesthetic management can substantially attenuate such intra and postoperative responses and thus may improve outcome (Anand et at, 1990). The use of opioids as a component of balanced
anesthesia can modify the stress response.
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The present study was suggested to evaluate and compare the effects of different narcotics as a component of balanced anesthesia on stress response to anesthesia and surgery including efficiency of analgesia, haemodynamic and autonomic stability as well as their effects on hormonal, and metabolic responses to anesthesia and surgery.
This study was done on 60 patients aged between 18-50 years, of both sexes (45 males and 15 females). They were fit, ASA category 1 and II, subjected to moderate elective surgeries (general and orthopedic) 1.5-2 hours duration. All patients were subjected to complete medical examination before operation. Patients with hepatic, renal disease, hypertension, ischemic heart disease, bronchial asthma or respiratory disease were excluded.
All operations were done at the same time of the day to avoid diurnal variations in hormonal level in blood. Non of the patients received blood transfusion or dextrose containing solution during the operation.
All patients were premedicated with midazolam 0.07 mg/kg and atrophic 0.01 mg /kg. Both drugs were given intravenously 10 min before induction. On arrival in the operating room, the patients were divided into 4 equal groups according to the drug used for induction and maintenance of anesthesia.
- Patients in groups 1, II, III, were given narcotic drugs for induction and
maintenance :
- Grotip I : morphine (morphine group).
- Group 11 : meperidine (meperidine group).
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- Group Ill: fentanyl (fentanyl group).
- Patients in group IV, were given thiopentone for induction and halothane
for maintenance of anesthesia (halothene group).
In groups I, II, III, equianalgesic doses of the narcotic drugs were given intravenously over 10 min. in divided doses up to 0.6 mg/kg morphine, 5mg/kg meperidine and 7.5 ug/kg fentanyl, for induction Supplementary sleep dose of thiopentone was given to the patients who did not loss their consciousness.
After loss of consciousness, all patients were given succinylcholine intravenously I mg/kg and trachea was intubated with portex cuffed tube. Anesthesia’ was maintained with 60% nitrous oxide in oxygen,
-p-
pancuronium 0.8 mg/kg was given and respiration was controlled to maintain normal blood gas tension. When signs of insufficient depth of anesthesia appeared the patient was given a supplementary dose of narcotic. If signs of insufficient depth of anesthesia were still found 10 min after narcotic supplementation, the patient was considered a narcotic fall-out, and no further opiate was given and a potent inhalational agent (Halothane) was added and no further hemodynamic data or blood sample was included in the study.
At the end of operation, residual neuromuscular blockade was reversed with neostigmine 2.5 mg and atropine ling, followed by discontinuation of nitrous oxide and 100% oxygen was substituted. After the patient being conscious (able to open eye) and breathing adequately (RR greater than 12 breaths/min), the patient was extubated. If respiration
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was insufficient (RR less than 8 breaths/min) the patient was given naloxone.
Patients in group IV were given sleep dose of thiopentone for induction, followed by suxamethonium and intubation. Anesthesia in group IV was maintained as described above in the other groups.
Haemodynamic parameters were measured : Before premedication, before induction, after induction, immediately and 5 min. after intubation, 5 min., 30 min. and 60 min. after skin incision, at the end of operation, after extubation and after full recovery.
Blood samples were taken at the following times : Before induction, after induction, immediately after intubation, 5 min. after skin incision, at the end of operation and 24 H postoperatively. Glucose oxidase test and cortisol enzyme immunoassay tests were done to every sample for glucose and cortisol levels measurements.
The actual induction narcotic dose /kg, the sleep dose of thiopentone /kg in group IV and supplementary sleep dose of thiopentone in the other narcotic groups were measured for each patient.
The following times were observed and recorded : The time to tirst supplement, the time between supplement, the time from NO2 discontinuation till the patient became, able to open his or her eyes on commands and oriented to name, day and place as well as the time from the end of operation till the patient asked for his first of analgesia.
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This study demonstrated that premedication with midazolam and atropine was associate with significant increase in heart rate and significant decrease in iolood pressure. The sleep dose of thiopentone was reduced in all groups, lowever, it was significantly less in the narcotic groups. It was 1.80 ± 0.19 mg/kg, 2.12 ± 0.13 mg/kg and 1.14 ± 0.19 mg/kg for morphine, meperidine and fentanyl groups respectively compared to 4.16 ± 0.24 mg/kg for halothane group.
The loading doses of the three narcotics were 0.58 ± 0.01 mg/kg in morphine group, 4.6 ± 0.14 mg/kg in meperidine group and 6.7 ± 0.3 ug/kg in fentanyl group. These loading doses were associated with significant increase in heart rate in meperidine group and significant decrease in blood pressure in fentanyl and morphine groups with no
intergroup difference.
This study showed that the pressor response to laryngoscopy and intubation in the non narcotic group was significantly higher than in the narcotic group, however, fentanyl was more effective than morphine and meperidine in attenuation the excitatory cardiovascular responses to laryngoscopy and intubation. Also, surgical stimulation produced significant increase in all variables measured in halothane group compared to the narcotic group, however, the responses to surgical stimulation were better suppressed by fentanyl than morphine or meperidine.
Unfortunately, the narcotic drugs in 26.7%, 33.3%, and 20% of the patients given, morphine, meperidine and fentanyl, respectively, failed to prevent the sympathoadrenal activity of surgery and necessitated the addition of a potent inhalational agent (halothane) to maintain anesthesia.
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At the time of emergence and extubation, all patients showed comparable signs of cardiovascular stimulation which was significantly increased in halothane group than the narcotic group, however, the pressor response was more suppressed in morphine group than fentanyl group.
The study showed that the patients in narcotic groups were awakened more rapidly than in halothane group, however, the recovery times, were significantly shorter in fentanyl and morphine groups than in meperidine group. Despite of rapid recovery in the narcotic groups, 26.7% of the patients in morphine, 33.3% in meperidine groups and 20% in fentanyl group required naloxone at the end of operation due to inadequate respiration. Postoperatively, the patients in fentanyl group who asked for analgesia, required pain medication more sooner than those in morphine and meperidine groups.
The study showed that inducation of anesthesia was associated with insignificant changes in blood glucose and cortisol levels in all groups, however, surgical stimulation caused progressive increase in glucose concentration which was significantly greater in halothane group with no significant difference between the narcotic groups. On the other hand, the cortisol response to surgery was partially suppressed in the narcotic groups compared to halothane group and was markedly suppressed in fentanyl group than the other two narcotic groups.
_,(1\A\
Results EaveiceethatTstmally ana yzed and discussed. It was found
that the use of opioid in small doses as a supplements during balanced ansthesia in a relatively short general surgical procedures, is of great
- 204 - advantage than the use of inhalational agents, as opioids used in the study can successfully suppress the hemodynamic as well as endocrinal and metabolic responses to the stressful intervals during operation with rapid recovery and postoperative analgesia and without postoperative respiratory depression. On the other hand, fentanyl is the most effective agent than the other two narcotic, with more hemodynamic stability and more suppression of endocrinal and metabolic responses to surgery, while
meperidine is the most unsatisfactory drug due to the high incidence of side effects.