Melatonin vs. midazolam premedication in children: a double-blind, placebo-controlled study.

BACKGROUND AND OBJECTIVE: Unlike midazolam, melatonin premedication is not associated with cognitive impairment in adults despite its anxiolytic properties. The use of melatonin as a premedicant in children has not been reported. This randomized, double-blind, placebo-controlled study compared the perioperative effects of different doses of melatonin and midazolam in children. METHODS: Seven groups of children (n = 15 in each) were randomly assigned to receive one of the following premedicants. Midazolam 0.1, 0.25 or 0.5 mg kg(-1) orally, melatonin 0.1, 0.25 or 0.5 mg kg(-1) orally each mixed in 15 mg kg(-1) acetaminophen, or placebo only (15 mg kg(-1) acetaminophen). Anxiety and temperament were evaluated before and after administration of the study drug, on separation from parents and on the introduction of the anaesthesia mask. At week 2 postoperatively, the behaviour of the children was measured by the Post Hospitalization Behaviour Questionnaire. RESULTS: Melatonin or midazolam each in doses of 0.25 or 0.5 mg kg(-1) were equally effective as premedicants in alleviating separation anxiety and anxiety associated with the introduction of the anaesthesia mask. A trend was noted for midazolam to prolong recovery times as the dosage increased. The use of melatonin was associated with a lower incidence (P = 0.049) of excitement at 10 min postoperatively, and a lower incidence (P = 0.046) of sleep disturbance at week 2 postoperatively than that observed with midazolam and control groups. No postoperative excitement was noted in the melatonin groups at 20, 30 and 45 min. DISCUSSION: Melatonin was not only as effective as midazolam in alleviating preoperative anxiety in children, but it was also associated with a tendency towards faster recovery, lower incidence of excitement postoperatively and a lower incidence of sleep disturbance at week 2 postoperatively.

Induced preconditioning of cardiac performance in coronary bypass surgery--sevoflurane vs propofol.

UNLABELLED: Twenty ASA III and IV adult patients scheduled for elective coronary artery surgery were included in the study. Anesthesia was induced and maintained with either sevoflurane (sevoflurane group; n = 10) or propofol (propofol group; n = 10). All preoperative cardiac medications were continued until the morning of surgery. There were significant decreases in mean arterial blood pressure, cardiac index and ejection fraction after CPB in propofol group compared with sevoflurane. Further, the plasma creatine kinase myocardial isoenzyme concentrations were significantly higher in propofol group but did not approach the critical values needed for diagnosis of myocardial infarction. CONCLUSION: It is concluded that, sevoflurane appears to be associated with better hemodynamic stability before and after CPB than propofol. This could be attributed to cardioprotective effect of sevoflurane during ischemia and reperfusion.

Traumatic aortic pseudoaneurysm.

A case report of a 5 years old male child, with a history of crash injury--(blunt trauma)--on the chest. Computed tomography (CT) scan, magnetic resonance imaging (MRI) of the chest revealed an aneurysm involving the arch of the aorta. An aortogram showed its exact extension. Chest X-Ray showed collapsed left lung (due to pressure of aneurysm on left main bronchus). Surgery was done o aortic arch: Resection of the aneurysm, and patch repair of aorta, under profound hypothermic circulatory arrest (PHCA) and CPB. Left bronchial tear was also closed. Post operatively the patient was ventilated for about 36 hours to allow for lung expansion. The patient had a smooth postoperative course. Intensive chest physiotherapy and repeated bronchoscopies helped in recovering the left lung function.

Anaesthesia for morbidly obese patients: a study of haemodynamic changes during bariatric surgery.

BACKGROUND AND AIMS: Morbid obesity with body mass index (BMI) > 40 kg/m2 requires surgical correction if the diet program fails. Laparoscopic adjustable gastric banding (LAGB) (bariatric surgery) is the standard surgical procedure. The haemodynamic effects of the typical pneumoperitoneum had been studied but, the additional effects of morbid obesity and the consequences of LAGB surgery had not. Therefore, we conducted this study to determine the haemodynamic changes under anaesthesia during bariatric surgery. MATERIALS AND METHODS: Under general anaesthesia, 7 patients (4 males) were studied. Their mean age was 36.2 yr (range 25-50 yr) and mean BMI was 49.7 kg/m2 (range 39.3-67.3). Besides routine monitoring of vital signs, non invasive cardiac output monitor (NICO, Novametrix, Wallingford, CT, USA) was used to monitor cardiac output (CO), cardiac index (CI) and stroke volume (SV). All the haemodynamic variables were taken at three phases: A) after induction of anaesthesia, B) during pneumoperitoneum and C) after gas deflation. RESULTS: The mean HR and BP showed significant high values during phase B compared to phase A. The mean values of CO were 7.2 +/- 1.1 and 9.06 +/- 2.6 L/min during phases A and B respectively with significant differences. The mean values of SV were 91.1 +/- 12.3 and 123.2 +/- 42.6 ml during phases A and B respectively with significant differences. The mean values of CI during phases A and B were 3.1 +/- 0.7 and 3.4 +/- 1.09 L/min/m2 respectively with significant differences. CONCLUSIONS: We have reported high CO and CI during pneumoperitoneum, which may be due to increased heart rate induced by sympathetic stimulation.

Right vs left side thoracoscopic sympathectomy: effects of CO2 insufflation on haemodynamics.

BACKGROUND AND AIMS: Currently, few reports of the haemodynamic impact of intrapleural CO2 insufflation in the clinical setting are available. Therefore, we conducted the present study to compare the haemodynamic changes between right and left side thoracoscopic sympathectomy (TS) for treatment of palmar hyperhidrosis (PH) under general anaesthesia. MATERIALS AND METHODS: 20 adult patients (17 males) undergoing TS were randomly allocated to two groups (each 10); group A, right side and group B, left side TS procedures were performed under general anaesthesia with single-lumen endotracheal tube. Besides the routine monitoring of vital signs, non-invasive cardiac output monitor (NICO) was used to record the stroke volume (SV), cardiac output (CO) and cardiac index (CI). Intrapleural CO2 insufflation was used. Anaesthesia was maintained with 1 MAC sevoflurane in 50% nitrous oxide in oxygen with incremental doses of sufentanil and atracurium when required. Haemodynamic parameters were obtained every 3 min then averaged over the time of surgery at phases; I) after tracheal intubation, II) after CO2 insufflation and III) after CO2 deflation. RESULTS: The CO, CI and SV showed decreased trend in both groups during phase II compared to phase I with significant differences (P < 0.05). Comparing the CO and CI variables revealed lower values in group A compared to group B but with non-significant differences (P > 0.05). While the SV variable showed significant low value in group A compared to group B (P < 0.05). CONCLUSIONS: Compared to left side TS, direct compression by CO2 against the venae cava and right atrium and ventricle during right side TS caused reduction of the venous return and hence low CO, CI and SV.

The use of low-dose rocuronium to facilitate laryngeal mask airway insertion.

In this two-phase study, the efficacy of low-dose rocuronium to facilitate laryngeal mask airway (LMA) insertion was evaluated. First, the onset time of 100, 150 and 300 micrograms.kg-1 rocuronium was determined using mechanomyography in three groups of patients (n = 10 in each) anaesthetized with propofol-fentanyl-nitrous oxide. In the second part, 100, 150 or 300 micrograms.kg-1 rocuronium or placebo was administered randomly to four groups of patients (n = 50 in each) in a double-blind manner. Following this, anaesthesia was induced with propofol 2.5 mg.kg-1. Patients in the group of 300 micrograms.kg-1 rocuronium or placebo received propofol after 1.5 min. Patients in the group of 100 or 150 micrograms.kg-1 rocuronium received propofol after 3 min. The LMA was inserted 90 sec later. Immediately before the induction of anaesthesia, patients were questioned about the symptoms of neuromuscular block. In phase 1, onset times were 180 sec (SD 41), 191 sec (59) and 89 sec (34), respectively. In phase 2, insertion of the LMA was graded as easy in 90.6% of patients receiving rocuronium, compared with 42% of patients who had only propofol (P < 0.05). Rocuronium improved the overall ease of LMA insertion. LMA insertion was graded easy in 80% of patients who received 100 micrograms.kg-1 rocuronium. The incidence of unpleasant effects was greatest with 300 micrograms.kg-1 rocuronium. The optimal dose needed to facilitate LMA insertion with minimal unpleasant effects appeared to be 100 micrograms.kg-1 rocuronium.

The incidence of bradycardia during endoscopic third ventriculostomy.

UNLABELLED: The incidence of bradycardia during endoscopic third ventriculostomy (ETV) is unknown. In an attempt to determine that incidence, we studied 49 pediatric patients with obstructive hydrocephalus who underwent ETV during general anesthesia. The median age was 54.5 mo (range 1-108 mo) and the median weight was 12.2 kg (range 2.4-22 kg). The heart rate was measured continuously in which four stages were identified for data analysis. Stage A is the preoperative phase, stage B is 5 min before perforating the floor of the third ventricle, stage C during perforation, and stage D after perforating the floor of the third ventricle. Three readings were recorded at each stage, then averaged. The mean values of the heart rate at stages A, B, C, and D were 146 +/- 27, 151 +/- 26, 87 +/- 32, and 143 +/- 24 bpm respectively. A significant decrease in the heart rate was determined in stage C compared with stage B (P: < 0.05). The incidence of bradycardia was 41%. Alerting the surgeon to perforate the floor of the third ventricle or withdraw the scope away from it was sufficient to resolve the bradycardia. We concluded that serious bradycardia might occur during ETV, mostly because of mechanical factors and can be resolved without medications. IMPLICATIONS: The use of endoscopy for treating pediatric patients with increased intracranial pressure is a new surgical procedure. These patients require general anesthesia with continuous heart rate monitoring. We have observed a high incidence of decrease in heart rate. If a decrease in heart rate occurs, alerting the surgeon to speed the procedure would be an effective treatment.

Wound closure tramadol administration has a short-lived analgesic effect.

PURPOSE: To evaluate the effects of tramadol administration at wound closure on postoperative pain and analgesic requirements in patients undergoing laparoscopic cholecystectomy. METHODS: In a prospective, randomized, double-blind study 80 patients were allocated into two groups (n = 40 in each) to receive either 200 mg tramadol or placebo i.v. at the time of wound closure. Postoperatively, all patients received tramadol from a patient-controlled analgesia (PCA) device. Pain, analgesic consumption, vital signs and side effects were recorded postoperatively for 24 hr. RESULTS: Administration of 200 mg tramadol at the time of wound closure was associated with a short-lived (60 min) reduction in pain scores and PCA consumption compared with placebo. Although the time to first request for analgesia after surgery was longer in patients who received tramadol at wound closure, there was no difference between the two groups with respect to pain scores or to the requirements of postoperative analgesia over the next 23 hr. The cumulative PCA consumption of tramadol in 24 hr was 139.4+/-108 and 102.4+/-106 mg in the placebo and tramadol groups, respectively (P = 0.06). CONCLUSIONS: Wound closure administration of 200 mg tramadol had a short-lived (60 min) analgesic effect but did not affect the long-term pain scores or analgesic requirements after laparoscopic cholecystectomy.

The comparative dose-response effects of melatonin and midazolam for premedication of adult patients: a double-blinded, placebo-controlled study.

UNLABELLED: We designed this prospective, randomized, double-blinded, placebo-controlled study to compare the perioperative effects of different doses of melatonin and midazolam. Doses of 0.05, 0.1, or 0. 2 mg/kg sublingual midazolam or melatonin or placebo were given to 84 women, approximately 100 min before a standard anesthetic. Sedation, anxiety, and orientation were quantified before, 10, 30, 60, and 90 min after premedication, and 15, 30, 60, and 90 min after admission to the recovery room. Psychomotor performance of the patient was evaluated at these times also, by using the digit-symbol substitution test and Trieger dot test. Patients who received premedication with either midazolam or melatonin had a significant decrease in anxiety levels and increase in levels of sedation preoperatively compared with control subjects. Patients in the three midazolam groups experienced significant psychomotor impairment in the preoperative period compared with melatonin or placebo. After operation, patients who received 0.2 mg/kg midazolam premedication had increased levels of sedation at 90 min compared with 0.05 and 0. 1 mg/kg melatonin groups. In addition, patients in the three midazolam groups had impairment of performance on the digit-symbol substitution test at all times compared with the 0.05 mg/kg melatonin group. Premedication with 0.05 mg/kg melatonin was associated with preoperative anxiolysis and sedation without impairment of cognitive and psychomotor skills or affecting the quality of recovery. IMPLICATIONS: Premedication with 0.05 mg/kg melatonin was associated with preoperative anxiolysis and sedation without impairment of cognitive and psychomotor skills or affecting the quality of recovery.

Spontaneous chylothorax--case report.

A-19-year old male patient complained of shortness of breath. Aspiration of the pleural fluid revealed chylothorax. Right chest tube was inserted. His ABG showed hypoxaemia with relative hypercarbia. He underwent right thoracotomy and thoracic duct ligation under general anaesthesia and double lumen endobroncheal intubation. During surgery he lost 1.5 L of blood and 4 L chyle. He was transferred to the SICU intubated and on mechanical ventilation. On the subsequent days chyle leak was reduced to a minimum of 10 ml/hr. On the 9th postoperative day the patient was extubated. He was receiving TPN 2600 kcal/day. He was transferred to the normal floor on the 15th day. After 7 day he was readmitted, his chest showed severe lung fibrosis and consolidation. His ABG showed severe hypercarbia (PaCO2 = 126 mmHg). The patient was intubated. His condition deteriorated and he was considered for lung transplantation. No donor was available. Later he arrested and died. Anaesthesia and surgical management of spontaneous chylothorax is challenging. The mortality rate is high.

Premedication with melatonin: a double-blind, placebo-controlled comparison with midazolam.

We have evaluated the perioperative effects of melatonin with those of midazolam in 75 women in a prospective, randomized, double-blind, placebo-controlled study. Patients were given sublingual midazolam 15 mg, melatonin 5 mg or placebo, approximately 100 min before a standard anaesthetic. Sedation, anxiety and orientation were quantified before, and 10, 30, 60 and 90 min after premedication, and 15, 30, 60 and 90 min after admission to the recovery room. Psychomotor performance was evaluated at these times also, using the digit-symbol substitution test (DSST) and the Trieger dot test (TDT). Patients who received premedication with either midazolam or melatonin had a significant decrease in anxiety levels and increase in levels of sedation before operation compared with controls. Midazolam produced the highest scores for sedation at 30 and 60 min after administration and significant psychomotor impairment in the preoperative period compared with melatonin or placebo. After operation, patients who received midazolam or melatonin premedication had increased levels of sedation at 30 min and impairment in performance on the DSST at 15, 30 and 90 min compared with controls. There were no significant differences between the three groups for anxiety levels or TDT performance after operation. Amnesia was notable only in the midazolam group for one preoperative event (entry into the operating room). Patient satisfaction was noted in the midazolam and melatonin groups only. We have demonstrated that melatonin can be used effectively for premedication of adult patients.

Death within 24 hours of anesthesia is not always an anesthetic death.

PURPOSE: We report an anesthetic death of a young lady after uneventful anesthetics. CLINICAL FEATURES: A 25-year-old female who had undergone emergency incision and drainage of an abscess in her right breast. Her condition, however, deteriorated few hours after anesthesia and died in less than 24 hours from causes unrelated to anesthesia. The computerized tomography (CT) scan showed a large meningioma in frontal lobe. CONCLUSION: This case illustrates that the risks of anesthesia are increased significantly in patients with silent meningionmas.

Predictive models for difficult laryngoscopy and intubation. A clinical, radiologic and three-dimensional computer imaging study.

PURPOSE: To identify the variables most useful in predicting difficult laryngoscopy and intubation from various clinical, skeletal (lateral x-rays) and soft tissue (three-dimensional computed tomography imaging) measurements. METHODS: Twenty-four adult patients in whom an unanticipated difficult tracheal intubation was identified according to established criteria were evaluated. Further, a control group of 32 patients in whom tracheal intubation was easily accomplished was studied. We applied multivariate discriminant analysis to clinical and radiological data of all patients to select those variables most useful in predicting difficult laryngoscopy and intubation. The receiver operating characteristic (ROC) curve was used to describe the discrimination abilities and to explore the trade-offs between sensitivity and specificity of the model. RESULTS: With the clinical data alone, discriminant analysis identified four risk factors that correlated with the prediction of difficult laryngoscopy and intubation: thyrosternal distance, thyromental distance, neck circumference and Mallampati classification. With both clinical and radiological data, discriminant analysis identified five risk factors: thyrosternal distance, thyromental distance, Mallampati classification, depth of spine C2 and angle A (the most antero-inferior point of the upper central incisor tooth). The positive predictive value of this combined (clinical and radiological) model was greater than that of the clinical model alone (95.8% vs 87.5%, respectively). The areas under the ROC curves, that measure the probability of the correct prediction of the clinical and the combined models, were found to be 0.933 and 0.973, respectively. CONCLUSIONS: These models can be used for predicting difficult laryngoscopy and intubation in clinical practice.

HELLP syndrome: undiagnosed in a case of impending rupture of uterus. A case report.

A 31-year-old women, 34 weeks gestation with intrauterine fetal death, and transverse lie with impending rupture of the uterus due to obstructed labor, was scheduled for urgent cesarean section. On preoperative anesthetic assessment, she was diagnosed to have HELLP syndrome based on clinical findings (subsequently confirmed by laboratory results). She was anesthetized taking the necessary precautions. Her intra and postoperative course is described. The case demonstrates how the anesthetist is often confronted by undiagnosed HELLP syndrome for urgent cesarean section and has limited time for investigations. He should depend on his clinical acumen to diagnose and treat appropriately for a favorable maternal outcome.

Comparative clinical pharmacology of rocuronium, cisatracurium, and their combination.

BACKGROUND: The comparative clinical pharmacology of cisatracurium and rocuronium and their combinations has not been reported. In this study, the authors compared the relative potency and the clinical profile and characterized the interaction of both drugs. METHODS: Two hundred twenty adults classified as American Society of Anesthesiologists physical status I and anesthetized with propofol-fentanyl-nitrous oxide were studied. In part 1, the neuromuscular-blocking effects of cisatracurium and rocuronium were assessed after administration of bolus doses of 20-50 microg/kg and 100-300 microg/kg, respectively. In part 2, we compared the time course of 1xED50, 1, 1.5, and 2xED95 doses of both drugs (where ED50 and ED95 are, respectively, the doses producing 50% and 95% depression of the first twitch height [T1]). In part 3, equieffective combinations of both drugs were studied to characterize their interaction. RESULTS: The calculated ED50 values and their 95% confidence intervals were 111 (107-115) and 26.2 (25.8-26.5) microg/kg [corrected] for rocuronium and cisatracurium, respectively. Compared with equipotent doses of cisatracurium, rocuronium had a faster onset, and a faster spontaneous T1 and train-of-four recovery times that were significant except at maximum recovery with the 2xED95 dose. The interaction between rocuronium and cisatracurium was synergistic, and the time profile of the combination group was different from that of the single-dose groups. CONCLUSIONS: Cisatracurium is four to five times more potent than rocuronium. Rocuronium had a faster onset of action, a shorter clinical duration, and a faster spontaneous recovery rate compared with equipotent doses of cisatracurium.