Biomedical subjects

C A Kenaan

Publications and source records attributed to C A Kenaan.

6 recordsLinked to original sources

PubMed2001

A multicenter evaluation of the time-course of action of two doses of rapacuronium after early and late reversal with neostigmine.

UNLABELLED: Early reversal of rapacuronium may accelerate return of neuromuscular function. This study was designed to compare early (2 min after rapacuronium) or late (at 25% recovery of the first twitch [T1] of train-of-four) reversal of rapacuronium with neostigmine. We studied 119 subjects between the ages of 18 and 75 yr. Anesthesia was induced with fentanyl and thiopental and maintained with nitrous oxide, propofol, and fentanyl. Mechanomyographic neuromuscular monitoring was performed by using train-of-four stimulation of the ulnar nerve. Two groups received 1.5 mg/kg rapacuronium followed by neostigmine (50 microg/kg) and glycopyrrolate (10 microg/kg) either at 2 min after rapacuronium bolus or at 25% T1 recovery. The other two groups received 2.0 mg/kg rapacuronium, after which neostigmine was similarly given. For each rapacuronium dose, the time from the administration of rapacuronium to the start of T1 recovery or 25% T1 recovery was significantly shorter in subjects who received the reversal 2 min after rapacuronium. However, late recovery, defined by times from administration of rapacuronium to 70%, or 80% T4/T1 recovery, was not influenced by early reversal administration. We conclude that initial recovery is accelerated by early administration of neostigmine. Time to full recovery after rapacuronium administration is, however, dose-dependent and not significantly altered by early administration of neostigmine. IMPLICATIONS: "Rescue reversal," which includes the administration of neostigmine shortly after the administration of rapacuronium, may accelerate the return of spontaneous breathing (early recovery), but does not shorten the time to complete recovery of upper airway function.

Adolescent↗

PubMed2000

Neuromuscular effects of rapacuronium in pediatric patients during nitrous oxide-halothane anesthesia: comparison with mivacurium.

PURPOSE: To describe neuromuscular effects of rapacuronium in pediatric patients during N2O-halothane anesthesia and compare them with mivacurium in children. METHODS: 103 pediatric patients, seven days -12 yr, received rapacuronium or mivacurium during N2O-halothane anesthesia. Onset and recovery of block were measured using EMG (Datex). Block was compared between groups based on drug treatment and age. Children < two years received 1 or 2 mg x kg(-1) rapacuronium: 2-12 yr received either 2 mg x kg(-1) or 3 mg x kg(-1) rapacuronium, or 0.2 mg x kg(-1) mivacurium. RESULTS: There were no differences in onset (1.7+/-1.8 min) or maximum block (T1 2.4+/-8%) among neonates, infants, and toddlers after either dose of rapacuronium. There was no difference between 1 and 2 mg x kg(-1) of rapacuronium block at 60 sec. Train-of-four ratio (T4/T1) >0.7 occurred later after 2 mg x kg(-1) than 1 mg x kg(-1) in these patients (P<0.05). There was no difference in T25 among neonates, infants and toddlers for 1 mg x kg(-1) or 2 mg x kg(-1) doses. Rapacuronium, 3 mg x kg(-1), produced maximum block 1.5 min earlier than did mivacurium, 0.2 mg x kg(-1) (P<0.001). There was no difference in block at 60 sec, maximum block or time to maximum block between 2 and 3 mg x kg(-1) rapacuronium for children > two years of age. Maximum block occurred 1.0+/-0.5 min after 2 or 3 mg x kg(-1) when T1 was 0.2+/-1.1% of baseline. T25 and T4/T1 >0.7 occurred 10 to 11 min later after this dose of rapacuronium than after mivacurium. CONCLUSION: Rapacuronium produces block earlier than mivacurium. Recovery from rapacuronium block is dose related and slower than that following mivacurium during halothane anesthesia.

Anesthesia, Inhalation↗

PubMed2000

Pharmacodynamics and intubating conditions of cisatracurium in children during halothane and opioid anesthesia.

STUDY OBJECTIVES: To determine the pharmacodynamics and intubating conditions of cisatracurium 0.2 mg/kg in children aged 2 to 12 years. DESIGN: Open-label, randomized study. SETTING: Operating room of a university-affiliated hospital. PATIENTS: 42 ASA physical status I and II patients, 24 to 155 months of age. INTERVENTIONS: Patients were assigned to one of two groups: halothane anesthesia (G1) and opioid anesthesia (G2). Subsequently, each group was divided into two age subgroups: 24-59 months and 60-155 months. All patients were premedicated with midazolam intranasal 0.1 to 0.2 mg/kg. In G1, anesthesia was induced with halothane up to 3% and N(2)O/O(2) (60-70/30-40%). Halothane was reduced to </=2%, 2 minutes before cisatracurium was administered. In G2, anesthesia was induced with fentanyl 2 mcg/kg and thiopental 5 mg/kg. Anesthesia was maintained with halothane 0.8-1.5% in N(2)O/O(2) in G1, and it was maintained with fentanyl, thiopental, and N(2)O/O(2) in G2. Electromyography (EMG) assessed the neuromuscular function of the adductor pollicis every 10 seconds with single-twitch supramaximal stimulus at induction and train-of-four at recovery. After obtaining EMG baseline, cisatracurium was administered. Onset time, time to 90% block, percentage of maximal block, clinical duration, and intubating conditions were recorded. For statistical analysis, Chi-square test, analysis of variance, and Tukey's test were used, with p-value less than 0.05. MEASUREMENTS AND MAIN RESULTS: Only first twitch (T(1)) recovery to 25% was significantly longer in patients aged 24 to 59 months who received halothane-based anesthesia, compared with those who received opioid-based anesthesia (p < 0.05). Onset time, maximum block, and intubating conditions did not differ between groups (p > 0.05). CONCLUSIONS: Cisatracurium 0.2 mg/kg offered acceptable intubating conditions at 90 seconds in 98% of pediatric patients, regardless of the anesthesia-based technique. Longer clinical duration in the halothane group in younger children may be due to age-related potentiation or to the small number of patients enrolled in the younger subgroup.

Anesthesia↗

PubMed1999

Influence of the priming technique on pharmacodynamics and intubating conditions of cisatracurium.

STUDY OBJECTIVES: To determine the effects of the priming technique on the intubating conditions and pharmacodynamics of different doses of cisatracurium. DESIGN: Open-label, randomized study. SETTING: Operating room of a university-affiliated hospital. PATIENTS: 60 ASA physical status I, II, and III female patients. INTERVENTIONS: Patients were randomly assigned to one of four groups. Patients from Groups 1, 2, and 3 received 0.01 mg/kg cisatracurium as a priming dose, and patients from Group 4 received placebo. Four minutes later, patients from Groups 1, 2, 3, and 4 received the following intubating doses of cisatracurium: 0.09 mg/kg, 0.14 mg/kg, 0.19 mg/kg, and 0.2 mg/kg, respectively. Anesthesia was induced with thiopental sodium, sufentanil, droperidol, and nitrous oxide (N2O; 6 L/min) in oxygen (O2; 4 L/min) and maintained with isoflurane up to 0.7%, N2O in O2, and sufentanil. Mechanomyography assessed the neuromuscular function of the adductor pollicis with train-of-four supramaximal impulses. The trachea was intubated when the amplitude of the first twitch decreased to 10% to 15% of control. MEASUREMENTS AND MAIN RESULTS: There were no significant differences among the groups regarding the demographic data, the value of the first twitch at 60 seconds, the time to 90% block, and the onset time. Clinical duration of cisatracurium was significantly different between Group 3 and Groups 1 and 2, whereas Group 4 differed significantly from Group 1. Intubating conditions did not differ significantly among the groups. CONCLUSION: When primed, cisatracurium 0.09 mg/kg and 0.14 mg/kg produced an onset time comparable with that of 0.2 mg/kg and allowed an earlier spontaneous recovery (p < 0.05). In this study, there was no benefit in priming cisatracurium 0.19 mg/kg.

Adjuvants, Anesthesia↗

PubMed1999

Rapacuronium for modified rapid sequence induction in elective caesarean section: neuromuscular blocking effects and safety compared with succinylcholine, and placental transfer.

We have compared rapacuronium 2.5 mg kg-1 (n = 20) with succinylcholine 1.5 mg kg-1 (n = 22) in a multicentre, blinded, randomized study in full-term parturients undergoing elective Caesarean section under general anaesthesia. Thiopental 5 mg kg-1 was given i.v. followed by the neuromuscular blocking agent. Sixty seconds later intubation was performed. Intubating conditions, evaluated as excellent, good or poor, were good to excellent in 95% and 91% in the intent-to-treat patients after rapacuronium and succinylcholine, respectively (ns). Mean onset times at the adductor pollicis muscle for rapacuronium and succinylcholine were 80.4 (SEM 14.4) s and 63.9 (5.6) s (ns) while maximum block was 96 (1.9)% and 99 (0.4)%, respectively (ns). Rate of recovery was significantly longer after rapacuronium; times for return of T1 to 25% were 16.9 (1.5) min and 9.6 (1.1) min for rapacuronium and succinylcholine, respectively (P = 0.0004). Maternal side effects included more tachycardia and skin erythema with rapacuronium; no maternal mortality or morbidity, including bronchospasm, occurred in either group. There were no neonatal adverse effects in either group based on: Apgar scores at 1 and 5 min; times to sustained respiration; neuroadaptive capacity scores at 15 min, 2 h and 24 h; and umbilical venous and arterial blood-gas values and acid-base status. At delivery (17.7 (3.2) min), mean maternal plasma concentrations of rapacuronium were 9041.4 (1259.1) ng ml-1 and 506.4 (24.9) ng ml-1 for Org 9488 (the main metabolite). Corresponding values for umbilical venous plasma were 808.0 (92.1) ng ml-1 and 59.1 (6.5) ng ml-1, and for umbilical arterial plasma, 361.4 (56.4) ng ml-1 and 29.7 (4.6) ng ml-1, respectively. Umbilical venous to maternal venous ratios for rapacuronium and Org 9488 were 8.8% (1.3)% and 10.2 (1.7)%, respectively.

Adolescent↗

PubMed1997

Negative pressure pulmonary edema after acute upper airway obstruction.

STUDY OBJECTIVES: To review the clinical characteristics and the pathogenesis of negative pressure pulmonary edema, and to determine its incidence in surgical patients. DESIGN: Retrospective case-report study. SETTING: Operating room, postanesthesia care unit and surgical intensive care of a teaching hospital. PATIENTS: 30 surgical adult ASA physical status I, II, III, IV, and V patients who suffered from negative pressure pulmonary edema during the period 1992-1995. MEASUREMENTS AND MAIN RESULTS: This study showed a rapid onset of negative pressure pulmonary edema after acute upper airway obstruction, due mainly to laryngospasm in the postoperative period and to upper airway pathology in the preoperative period. Negative pressure pulmonary edema appeared more frequent in healthy (ASA physical status I and II), middle-aged and male patients, with a general incidence of 0.094%. The resolution was relatively rapid after reestablishment of the airway, adequate oxygenation, and positive airway pressure application. The clinical course was uncomplicated in all the patients. CONCLUSIONS: In this study, negative pressure pulmonary edema presented a relatively high incidence. Prevention, early diagnosis, and prompt treatment allowed a rapid and uncomplicated resolution.

Acute Disease↗