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Biomedical subjects

J Lerman

Publications and source records attributed to J Lerman.

At least 55 records · Page 3Linked to original sources

Incidence of malignant hyperthermia reactions in 2,214 patients undergoing muscle biopsy.

To determine the incidence of malignant hyperthermia (MH) reactions after trigger-free anaesthesia in a large population of MH-susceptible (MHS) patients, the charts of 2,214 patients who underwent elective muscle biopsy for malignant hyperthermia were reviewed. Either general or regional anaesthesia with non-triggering drugs was used. For general anaesthesia, the trachea was intubated in the absence of muscle relaxants. The halothane/caffeine contracture test was performed on the biopsied muscle. Suspected MH reactions were identified according to their site of occurrence (in the operating room, recovery room or ward). Ninety-seven percent of patients received a general anaesthetic; 3% received a regional anaesthetic or field block. Of the 2214 patients whose muscles were biopsied, 1082 patients were biopsy-positive for MH. Five patients in whom MH reactions were diagnosed in the recovery room were all subsequently proved to be biopsy-positive for MH. Four of the five received intravenous dantrolene as part of their therapy; the fifth received only symptomatic therapy as parenteral dantrolene was not commercially available. All patients recovered completely from their reactions. We conclude that the incidence of MH reactions in biopsy-positive patients who receive a trigger-free anaesthetic for minor surgery is small (0.46%, (0.15-1.07%, 95% CI)). These reactions occur in the immediate postoperative period.

Adolescent↗

Pharmacokinetics of intravenous ondansetron in healthy children undergoing ear, nose, and throat surgery.

BACKGROUND: To determine the pharmacokinetics of the 5-HT3 antagonist ondansetron in children, informed written consent was obtained from the parents of 21 healthy children aged from 3 to 12 years scheduled for ear, nose, and throat surgery. METHODS: The children were stratified according to age: 3 to 7 years and 7.1 to 12 years, and a single intravenous infusion of 2 or 4 mg ondansetron, respectively, was administered over 5 minutes before induction of anesthesia. After completion of the infusion, anesthesia was induced intravenously and maintained with inhalational anesthesia. Whole blood (3 ml) was obtained before administration of ondansetron, at completion of the infusion, at the beginning and end of surgery, and at 3, 4, 6, 8, 10, and 12 hours after start of the infusion. Pharmacokinetic variables were determined with use of standard noncompartmental techniques. RESULTS: Mean plasma clearance was 0.50 L.hr-1.kg-1 and 0.39 L.hr-1.kg-1, the mean volume of distribution at steady-state was 1.70 L.kg-1 and 1.61 L.kg-1, and the mean plasma terminal half-life was 2.6 hours and 3.1 hours for the 2 mg and 4 mg groups, respectively. On a body surface area basis, mean plasma clearance was 14.0 and 13.7 L.hr-1.m-2 and mean volume of distribution was 47.7 and 55.9 L.m-2 for the 2 and 4 mg groups, respectively. There were no serious adverse events attributable to ondansetron. CONCLUSIONS: These data indicate that the pharmacokinetics of ondansetron in children from 3 to 12 years old are predictable and similar to those in adults. The elimination half-life of ondansetron increases in parallel with age. However, clearance is constant when normalized to body surface area, but the volume of distribution increases over the age range studied.

Adenoidectomy↗

Clinical characteristics of sevoflurane in children. A comparison with halothane.

BACKGROUND: For pediatric patients, sevoflurane may be an alternative to halothane, the anesthetic agent used most commonly for inhalational induction. The induction, maintenance, and emergence characteristics were studied in 120 unpremedicated children 1-12 yr of age randomly assigned to receive one of three anesthesia regimens: sevoflurane with oxygen (group S), sevoflurane with nitrous oxide and oxygen (group SN), or halothane with nitrous oxide and oxygen (group HN). METHODS: Anesthetic was administered (via a Mapleson D, F or Bain circuit) beginning with face mask application in incremental doses to deliver maximum inspired concentrations of 4.5% halothane or 7% sevoflurane. End-tidal concentrations of anesthetic agents and vocal cord position were noted at the time of intubation. Elapsed time intervals from face mask application to loss of the eyelash reflex, intubation, surgical incision, and discontinuation of the anesthetic were measured. Heart rate, systolic, diastolic, and mean blood pressures, and end-tidal anesthetic concentrations were measured at fixed intervals. Anesthetic MAC-hour durations were calculated. The end-tidal concentration of anesthetic was adjusted to 1 MAC (0.9% halothane, 2.5% sevoflurane) for at least the last 10 min of surgery. Intervals from discontinuation of anesthetic to hip flexion or bucking, extubation, administration of first postoperative analgesic, and attaining discharge criteria from recovery room were measured. Venous blood was sampled at anesthetic induction, at the end of anesthesia, and 1, 4, 6, 12, and 18-24 h after discontinuation of the anesthetic for determination of plasma inorganic fluoride content. RESULTS: Induction of anesthesia was satisfactory in groups SN and HN. Induction in group S was associated with a significantly greater incidence of excitement (35%) than in the other groups (5%), resulting in a longer time to intubation. The end-tidal minimum alveolar concentration multiple of potent inhalational anesthetic at the time of intubation was significantly greater in patients receiving halothane than in patients receiving sevoflurane. Induction time, vocal cord position at intubation, time to incision, duration of anesthesia, and MAC-hour duration were similar in the three groups. During emergence, the time to hip flexion was similar among the three groups, whereas the time to extubation, time to first analgesic, and time to attaining discharge criteria were significantly greater in group HN than in groups S and SN. Mean heart rate and systolic blood pressure decreased during induction in group HN but not in groups S and SN. The maximum serum fluoride concentration among all patients was 28 microM. CONCLUSIONS: Sevoflurane with nitrous oxide provides satisfactory anesthetic induction and intubating conditions; however, induction using sevoflurane without nitrous oxide is associated with a high incidence of patient excitement and prolonged time to intubation. There were greater decreases in heart rate and systolic blood pressure during induction with halothane than with sevoflurane; however, these differences may be dose-related. The more rapid emergence with sevoflurane when compared with halothane is consistent with the low solubility of sevoflurane in blood and tissues. Children receiving sevoflurane for up to 9.6 MAC-hours did not develop high serum fluoride concentrations.

Anesthesia, Inhalation↗

Metered-dose inhaler salbutamol-induced tracheal epithelial lesions in intubated rabbits. Effects of the site of administration and time.

STUDY OBJECTIVES: To determine (1) whether metered-dose inhaler (MDI) salbutamol administered at the elbow connector of the anesthetic circuit produced tracheal epithelial lesions in intubated rabbits, and (2) the time course for resolution of tracheal lesions produced by MDI salbutamol through an intratracheal catheter. DESIGN: Prospective, randomized, controlled trial. SETTING: University-affiliated animal research laboratory. PARTICIPANTS: Thirty-nine adult New Zealand white rabbits. INTERVENTIONS: (1) Twenty-one intubated rabbits received 0,5, or 20 puffs of MDI salbutamol delivered at the elbow connector of the anesthetic circuit. (2) Eighteen intubated rabbits received five puffs of MDI salbutamol through an intratracheal catheter and were killed 1 h, 24 h, or 1 week later. MEASUREMENTS: Samples of trachea, bronchi, and lungs were examined by light microscopy, and the degree of epithelial injury was assessed semiquantitatively. RESULTS: MDI salbutamol (5 or 20 puffs) administered at the elbow did not induce tracheal epithelial injury. When administered through an intratracheal catheter, MDI salbutamol (five puffs) produced moderate or severe tracheal epithelial injury in those killed 1 h after the study. Evidence of epithelial regeneration was observed 24 h after the injury and recovery was virtually complete by 1 week. CONCLUSION: Epithelial lesions do not occur when the MDI salbutamol (5 or 20 puffs) is administered at the elbow connector of the ventilation circuit. Tracheal epithelial lesions produced by MDI salbutamol (five puffs) administered through an intratracheal catheter resolve within 1 week of the injury.

Albuterol↗

Oral premedication for paediatric ambulatory anaesthesia: a comparison of midazolam and ketamine.

To compare the clinical characteristics of two oral premedicants, midazolam and ketamine, 40 healthy children, one to six years of age, who were scheduled for ambulatory dental surgery, were assigned to receive either oral midazolam 0.5 mg.kg-1 or oral ketamine 5.0 mg.kg-1 in a double-blind, randomized study. Sedation and anxiolysis scores before induction, cooperation at induction of anaesthesia and recovery times and complications were assessed. We found that both drugs effectively sedated the children within 20 min of administration. Although sedated, 10% of the children in the midazolam group and 20% of those in the ketamine group became tearful on separation from their parents and 20% of those in the midazolam group and 35% of those in the ketamine group became tearful when the facemask was applied. No important side effects were attributable to either premedication. The time until the children were fit for discharge from the hospital after midazolam was approximately 20 min less than after ketamine. In conclusion, midazolam and ketamine offer similar clinical characteristics when used as oral premedications for children undergoing ambulatory surgery, although the time to discharge from hospital may be more rapid after midazolam than after ketamine.

Administration, Oral↗

The incidence of masseter muscle rigidity after succinylcholine in infants and children.

To determine whether the incidence of masseter muscle rigidity is affected by the anaesthetic induction sequence, we prospectively studied for ten months the anaesthetic course in 5,641 infants and children who received muscle relaxation to facilitate tracheal intubation. The anaesthetic induction sequence consisted of intravenous sodium thiopentone (STP) 5 mg.kg-1 alone, halothane induction alone 1-4%, or halothane followed by STP. Inhalational inductions with halothane included nitrous oxide and oxygen. Tracheal intubation was facilitated by either intravenous succinylcholine (Sch) at least 1.5 mg.kg-1 or by a non-depolarizing muscle relaxant. The induction sequence and all episodes of MMR were recorded. Ninety percent of the patients received Sch and 10% received a non-depolarising agent. Of those who received Sch, 88% (5,064 patients) were anaesthetised with STP and 12% (607 patients) were anaesthetised with halothane alone or halothane followed by STP. Masseter muscle rigidity was defined clinically by the transient inability to distract the mandible from the maxilla such that the mouth could not be opened or could only be opened with force. No children anaesthetised with STP followed by Sch developed MMR. One child (0.9%) developed MMR after halothane and Sch and two developed MMR after halothane, STP and Sch (0.4%). The incidence of MMR after Sch was less with STP than with halothane alone or with halothane and STP (P < 0.025). The peak CPK values in the three children who developed MMR were 17,580 IU.L-1 after halothane and Sch, and 7,280 IU.-1 and 3,273 IU.-1 after halothane, STP and Sch. There was no evidence of MH reactions in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗

The effect of adenosine-induced hypotension on systemic and splanchnic hemodynamics during halothane or sevoflurane anesthesia in the rat.

BACKGROUND: It has been suggested that the liver may be at risk for ischemic damage during adenosine-induced hypotension. This notion, however, is somewhat inconsistent with the understanding that adenosine is a powerful vasodilator of the splanchnic circulation. To help clarify the effect of adenosine-induced hypotension on splanchnic hemodynamics, we studied the systemic and splanchnic hemodynamic responses to adenosine, both alone and in the presence of halothane or sevoflurane. METHODS: Systemic and splanchnic hemodynamics were determined during the infusion of adenosine in 36 rats allocated randomly to one of three study groups: (1) awake, (2) halothane anesthesia (1.0 MAC), or (3) sevoflurane anesthesia (1.0 MAC). Adenosine was infused at a rate sufficient to decrease the mean arterial pressure by 35-38% from awake control values. Cardiac output and organ blood flows were measured using the radiolabeled microsphere technique. RESULTS: Adenosine infusion produced stable hypotension of rapid onset due to a reduction in systemic vascular resistance. Stroke volume increased, but cardiac output remained unchanged in the awake and sevoflurane groups because of a decrease in heart rate. Infusion of adenosine during halothane anesthesia increased cardiac output enough to compensate for the decrease in cardiac output due to halothane alone. In the splanchnic circulation, there was an increase in portal tributary (42%, P < 0.01) and hepatic arterial (38%, P < 0.05) blood flows during adenosine infusion in awake rats. This resulted in an overall increase in total liver blood flow (42%, P < 0.01). Halothane anesthesia was associated with a decrease in portal tributary blood flow (28%, P < 0.05). In contrast, sevoflurane anesthesia was associated with an increase in hepatic arterial flow (35%, P < 0.05) but with no change in portal tributary blood flow. During halothane anesthesia, adenosine infusion increased portal tributary (90%, P < 0.01) and hepatic arterial (37%, P < 0.05) blood flows, thereby increasing total liver blood flow to values similar to those in awake adenosine-infused rats. During sevoflurane anesthesia, adenosine infusion increased portal tributary blood flow (48%, P < 0.01), but hepatic arterial blood flow did not increase beyond the values observed during sevoflurane anesthesia alone. CONCLUSIONS: These findings demonstrate that adenosine is a potent vasodilator of portal tributary and hepatic arterial vasculature in the rat and that the splanchnic hemodynamic effects of adenosine predominate over those of halothane and sevoflurane.

Adenosine↗

The pharmacology of sevoflurane in infants and children.

BACKGROUND: Sevoflurane is a new volatile anesthetic with physical properties that should make it suitable for anesthesia (MAC of sevoflurane on oxygen alone and in 60% nitrous oxide, (MAC) of sevoflurane in oxygen alone and in 60% nitrous oxide, the hemodynamic, induction and emergence responses to sevoflurane and the metabolism to inorganic fluoride were studied in 90 ASA physical status 1 or 2 neonates, infants, and children. METHODS: MAC of sevoflurane in oxygen was determined in six groups of subjects stratified according to age: full-term neonates, infants 1-6 and > 6-12 months and children > 1-3, > 3-5 and > 5-12 yr. MAC in 60% nitrous oxide was determined in a separate group of children 1-3 yr of age. After an inhalational induction, the trachea was intubated (except for neonates in whom an awake intubation was performed). MAC for each age group was determined using the Up-and-Down technique of Dixon. RESULTS: MAC of sevoflurane in neonates, 3.3 +/- 0.2% and in infants 1-6 months of age, 3.2 +/- 0.1%, were similar; MAC in older infants 6-12 months and children 1-12 yr was constant at approximately 2.5%; MAC of sevoflurane in 60% nitrous oxide in children 1-3 yr of age was 2.0 +/- 0.2%. Systolic arterial pressure decreased significantly at 1 MAC before skin incision compared with awake values in all subjects except children 1-3 yr with 60% nitrous oxide and children 5-12 yr in oxygen, and then returned toward awake values after skin incision. Heart rate was unchanged at approximately 1 MAC sevoflurane before incision compared with awake values in all subjects except children > 3-5 and > 5-12 yr in whom heart rate increased before incision. Induction of anesthesia, particularly with respect to airway irritability, and emergence from sevoflurane anesthesia were not remarkable. The plasma concentration of inorganic fluoride reached maximum values (8.8-16.7 microM) 30 min after discontinuation of anesthesia. CONCLUSIONS: We conclude that sevoflurane appears to be a suitable anesthetic agent for use in neonates, infants and children undergoing < or = 1 h of anesthesia.

Aging↗

Proximate delivery of a large experimental dose from salbutamol MDI induces epithelial airway lesions in intubated rabbits.

The delivery of aerosolized drugs by metered dose inhaler (MDI) to intubated patients can be substantially improved by actuating the MDI through a narrow catheter placed inside the tracheal tube. However, the deposition of increased quantities of drug, surfactant, in particular oleic acid, and chlorofluorocarbon propellants on the lung surface could result in adverse effects not observed after oral MDI administration. To investigate this hypothesis, 42 adult intubated rabbits (six groups, n = 6 to 9/group) received Ventolin MDI, Ventolin placebo, a placebo MDI containing lecithin as surfactant, instilled salbutamol sulfate, instilled oleic acid solution, or no treatment (control). Heart rate, invasive blood pressure, and hemoglobin oxygen saturation, recorded continuously for the 3-h experiment, were unchanged from baseline (awake) values. Sections of trachea and lungs were reviewed blindly and graded using a four-point, nine-variable Ophoven scale. Blood was obtained after either 1 puff or 20 puffs MDI salbutamol to determine the pharmacokinetic profile of salbutamol. Multiple doses of both Ventolin and Ventolin placebo aerosols produced significant lesions to the epithelium of the trachea and main bronchi (p < 0.05). The histologic injury after lecithin placebo or salbutamol solution did not differ significantly from control, and all were significantly less than that observed after Ventolin MDI administration. Instilled oleic acid caused gross airway lesions. Maximum serum concentrations of salbutamol were 4.4 +/- 1.8 ng/ml after 1 puff and 419 +/- 168 ng/ml after 20 puffs. After 20 puffs, the total body clearance of salbutamol was 108 +/- 27 ml/min/kg, volume of distribution was 3.6 +/- 1.8 L/kg, and the elimination half-life was 22 +/- 7 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuterol↗

Publication of abstracts presented at anaesthesia meetings.

To determine the publication rate of abstracts as peer-reviewed manuscripts during the five years subsequent to their presentation, the rates of publication of abstracts that were presented at meetings of four anaesthesia societies (American Society of Anesthesiologists (ASA), International Anesthesia Research Society (IARS), Anaesthesia Research Society (ARS) and Canadian Anaesthetists' Society (CAS), in 1985 were determined. Abstracts (total = 215) from each of the four meetings were selected (ASA n = 114/573 total, IARS n = 39/119, ARS n = 33/99 and CAS n = 29/58) and their appearances in the literature as peer-reviewed manuscripts were determined using MEDLINE for the years 1985 to 1990 under the surname of the presenting author. The contents of the abstracts were compared with those of the resultant manuscripts. The proportions of abstracts from each of the four societies that were published as manuscripts were compared. We found that the mean proportion of abstracts from all four societies that were published as manuscripts within three years of presentation was 44% and within five years 50%. The proportions of abstracts that were published as manuscripts from the four societies were similar. Of the abstracts that were published as manuscripts, 13% from the ASA, 16% from the IARS, 16% from the ARS and 0% from the CAS were published four or five years after abstract presentation. Although the overall proportion of abstracts that was published within five years of presentation did not differ from the rate of publication within three years, we recommend that a uniform policy with respect to the time interval for citation of abstracts be adopted for all anaesthesia journals.

Abstracting and Indexing↗

Oral midazolam premedication in children: the minimum time interval for separation from parents.

To determine the minimum time interval between oral midazolam (0.5 mg.kg-1) premedication and separation from parents that ensures a smooth separation, 30 children were assigned randomly to one of three groups (ten children per group). The groups differed only in the time interval between administration of midazolam and separation from their parents: 10, 20 or 30 min. Heart rate, systolic blood pressure, and sedation and anxiolysis scores were assessed before midazolam premedication (baseline), at the time of separation from parents, and during the application of a face mask at the induction of anaesthesia. We found that heart rate and systolic blood pressure changes were similar for all three groups throughout the study period. Sedation scores at the time of separation from parents and on application of the mask for all three groups were greater than baseline values. Sedation scores at separation did not differ among the three groups. Anxiolysis values did not differ from baseline values at any time for all three groups. We conclude that children may be separated from their parents as early as ten minutes after receiving oral midazolam, 0.5 mg.kg-1.

Administration, Oral↗

Oral midazolam premedication for children with congenital cyanotic heart disease undergoing cardiac surgery: a comparative study.

To determine whether oral midazolam is a safe and effective alternative to our current standard premedication for children with cyanotic congenital heart disease (CCHD), 30 children aged 1-6 yr, scheduled for elective cardiac surgery, were studied. The children were randomly assigned to one of two groups: Group I received oral midazolam 0.75 mg.kg-1 30 min before separation from their parents in the surgical waiting area, and Group II received oral or rectal pentobarbitone 2 mg.kg-1 at 90 min, and morphine 0.2 mg.kg-1 and atropine 0.02 mg.kg-1 im at 60 min before separation. Heart rate, haemoglobin oxygen saturation (SpO2) and anxiolysis and sedation scores were recorded at four times during the study: at baseline (immediately before premedication), immediately after administration of the premedication, at separation of children from parents in the waiting area and at the time of application of the face mask in the operating room. We found that in Group I, anxiolysis improved at separation from parents compared with baseline (P < 0.05) and sedation increased both at separation and on mask application (P < 0.05), whereas in Group II anxiolysis did not change at any time and sedation increased only at separation (P < 0.05). Intramuscular injection of morphine produced a transient decrease in mean SpO2 (from 84% to 76%) (P < 0.05) that did not occur after ingestion of oral midazolam. The results of this study indicate that oral midazolam is a safe and effective replacement for the standard premedication for children with CCHD undergoing cardiac surgery and avoids the decrease in SpO2 associated with im injections.

Administration, Oral↗

Are all preterm infants younger than 60 weeks postconceptual age at risk for postanesthetic apnea?

BACKGROUND: Preterm and ex-preterm infants are at risk for life-threatening apnea after general anesthesia. The authors attempted to define the postconceptual age beyond which apnea is less likely to occur and to identify the factors that predispose to postanesthetic apnea. METHODS: Ninety-one infants younger than 60 weeks postconceptual age undergoing 101 general anesthetics were prospectively studied. All infants were admitted to the hospital for cardiorespiratory monitoring overnight. The presence of coexistent medical conditions that could influence the incidence of apnea was determined by a review of current and previous medical records and by history. RESULTS: Of 38 procedures performed in 35 infants younger than 44 weeks postconceptual age, 10 (26.3%) procedures in 9 infants were associated with postanesthetic apnea. In eight of these, apnea did not resolve spontaneously: four infants required stimulation, and four required continuous positive airway pressure by face mask. Apnea occurred after 2 of 63 procedures performed in infants 44 weeks postconceptual age or older. Both episodes occurred in one patient who had neurologic disease. Of the remaining 61 procedures in the latter age group, 7 were associated with episodes of bradycardia (lowest heart rate was 79 beats/min) postoperatively without apnea. These episodes lasted up to 5 s, were not associated with apnea or cyanosis, and resolved spontaneously in all cases. All infants with postanesthetic apnea and/or bradycardia experienced their first episode within 12 h after surgery. CONCLUSIONS: Ex-preterm infants younger than 44 weeks postconceptual age are at greater risk for apnea after general anesthesia than are infants older than 44 weeks postconceptual age. Based on these results, the maximum long-run risk of postanesthetic apnea in preterm infants older than 44 weeks postconceptual age is 5% with 95% confidence.

Age Factors↗