Drug interaction between halothane anaesthesia and the alpha[2]-adrenergic agonist, Ca[+2] entry blockers and K[+]-channel openers with possible effects on brain catecholamines

The interaction between halothane anaesthesia and 3 important groups of drug viz: alpha[2] adrenergic agonist [clonidine], Ca[+2] entry blocker [diltiazem] and K[+] channel opener [nicorandil] was studied in Albino rats. Rats were pretreated with clonodine [Catapress] 0.1 mg/kg b.wt. in clonidine group, with Diltiazem[Diltiem] 0.25 mg/kg b.wt. in diltiazem group and with nicorandil [Sigmart] 0.2 mg/kg b.wt. in nicorandil group. Drugs were given one hour before exposure to halothane anaesthesia. It was found that, clonidine resulted in reduction of the anaesthetic requirements with associated significant decrease of brain catecholamines from the mean control value of 620,584 +/- 28,460 pg/ml to the mean value 351.548 +/- 31.700 pg/ml [F = 163.636 at P > 0.05]. The other two groups showed no significant changes

Fiberoptic intubation: evaluation of two methods to obtund the pressor response

This study was performed on 40 adult patients to compare the efficacy of pretreatment with fentanyl or lidocaine IV. for supression of haemodynamic stress response in nasotracheal oriorotracheal fiberoptic intubation. Heart rate, mean arterial blood pressure, rate-pressure product showed significant decrease after fentanyl pretreatment which provided a good opportunity for successful a wake fiberoptic intubation inspite of minimal cardiovascular instability in the form of ventricular extrasystole in 3 patients. Also IV. lidocaine was effective in attenuating but not completely blocking cardiovascular response. In conclusion, fiberoptic intubation provided the better visualization of tissues and vocal cords; thus, decreasing the possibility of mechanical trauma but needs a good training program. Pretreatment with fentanyl and/or lidocaine should be used in an attempt to combat the cardiovascular responses during fiberoptic intubation, especially in patients in whom the pressor response to intubation is particularly hazardous

Evaluation of acute isovolemic hemodilution with halothane-induced hypotension in pediatric anesthesia

The effects of combined acute isovolemic hemodilution and halothane induced hypotension on some hemodynamic parameters, arterial blood gases, acid-base status and the operative blood loss were studied in 20 children scheduled for major intraabdominal operations. The blood was withdrawn via the central venous line and simultaneously replaced with three times the volume of Ringer's lactate solution. Autologous blood was reinfused either when the hematocrit value dropped to 15% or otherwise at within mean arterial blood pressure range from 54.30 +/- 1.88 to 65.77 +/- 2.08 torr. The minimal mean hemoglobin concentration value was 6.20 +/- 0.09 g/dl with a corresponding mean hematocrit value of 20.1 +/- 1.90%. The mean PaO2 [on 100% O2] dropped significantly during the hemodilution to the minimal mean value of 385.8 +/- 11.55 torr [p <0.05] and postoperatively to the mean value 386.5 +/- 10.99 torr [p <0.05]. PaCO2, standard bicarbonate, base deficit and pH were unchanged. No single case needed homologous transfusion. In conclusion, the combined isovolemic hemodilution and halothane-induced hypotension is a safe and reliable technique for reducing the intraoperative bleeding. It can be employed as one component of blood conservation program

Propofol versus thiopentone as a sole anaesthetic agent in children: a comparative study

In a comparative study, 40 children were included in 2 equal groups to study the characteristics of either propofol or thiopentone as a sole anaesthetic agent in minor day-stay surgical procedures. Propofol was given in a dose of 2.5 mg.Kg[-1], while thiopentone was given in a dose of 4-5 mg.Kg[-1]. It was found that respiratory rate, systolic, diatolic and mean arterial blood pressures decreased significantly from the preinduction values [P< 0.05]. The heart rate decreased significantly after propofol, while it showed a significant increase after thiopentone administration. The incidence of pain on injection was significantly more in propofol than in thiopentone injection. Airway obstruction was seen in 25% of propofol group, while it was manifested in 40% of thiopentone group. Mild laryngeal spasm was manifested in 5% of propofol group patients, while it was seen in 15% of thiopentone group patients. Apnoea occurred in 25% of propofol group children and in 10% of thiopentone group children. It was of longer duration in the former group. Propofol was associated with significantly rapid and clear recovery from anaesthia than thiopentone, otherwise it offers no advantage over thiopentone as a short-acting anaesthetic agent

Necurotoxic effect of intrathecal ketamine HCl: an experimental study in rabbits

Ketamine hydrochloride was injected intrathecally to study the possible acute and delayed neurotoxic effects in rabbits. In a dose of 2 mg.Kg-I b.wt., ketamine could produce analgesia to 70% of rabbits as manifested by hindpaw-pinch test and hot-plate test. No motor involvement nor behavioral changes were reported. Ketamine in a dose of 5 mg.kg-I b.w.t. Could produce analgesia in 100% of the animals, motor dysfunction and behavioral changes in the form of excitation and confusion followed by catalepsy. Histopathologically, oedema of the nerve cells was the general acute finding, being more marked in the high-dose group. The delayed effect of the drug was in the form of demyelination of the neurones. Also, the reaction was more marked in the high-dose group with chromatolysis of the cells and vascular proliferation. From the study, it was concluded that intrathecal ketamine HCI in rabbits caused neurotoxic effects in a dose-related manner, while behavioral changes were observed only under high dosage of the drug

Efficacy of combined magnesium sulphate and nifedipine therapy on catecholamines level in preeclamptic eclamptic parturients

Fifteen preeclamptic-eclamptic patients were enrolled in this study. Nifedipine 10 mg/4 hours and magnesium sulphate 6 gms IV. Initial dose followed by 1 gm/hr were administered till clinical recovery. The maximum mean therapeutic level of M[g]so4 was 7.58 +/- 0.71 mg/dl. Plasma level of catecholamines dropped significantly from pre-treatment level of 665.8 +/- 73.69 pg/ml to 360 33 +/- 38.44 pg/ml after discontinuation of drug therapy [t=24.42, P< 0.001]. It was concluded from the study that high plasma level of catecholamines was invariably present in toxaemic patients, therapeutic rigemen described succeeded in reversing these changes

Study of renal functions and some related parameters in preeclamptic parturients under epidural analgesia

Fifteen preeclamptic parturients scheduled for elective Caesarian section were enrolled. Renal functions and some related parameters [haematocrit, relative whole blood viscosity and serum levels of sodium and potassium] as well as the effects of epidural analgesia on them were studied. Preoperatively, patients were prepared by nifedipine 10mg/4 hr to control hypertension and for hydration one litre dextran 70 was given. Post-operatively, serum uric acid and urine-protein content were significantly decreased, while creatinine clearance and urine output showed definite increases. Haematocrit and relative whole blood viscosity were reduced. Proper preoperative management can ameliorate the renal insult in these patients

Study of the effects of atropine sulphate premedication on body temperature and heart rate in children

Atropine sulfate was used as a sole premedicant drug in pediatric anesthesia by two routes of administration [subcutaneous or intermuscular injection] to determine its effect on core and skin temperatures as well as the heart rate and rhythm. Two groups, each consisted of 20 children, were included in the study. Atropine sulphate was used in a dose of 0.01 mg/kg body weight 45 minutes before induction of anaesthesia. Measurements made were core and skin temperature, heart rate, calculated mean arterial blood pressure and electrocardiographic tracing. Both routes of administration caused decreased core body temperature and a rise in skin temperature, increased heart rate, a decrease in calculated mean arterial blood pressure and the same electrocardiographic changes in the form of sinus tachycardia. The intramuscular route caused more core heat loss, more tachycardia, more decrease in the mean arterial blood pressure