Sevoflurane causes more postoperative agitation in children than does halothane

BACKGROUND: An agitated recovery may occur after inhalation anesthesia. The aim of the present study was to assess the recovery quality after mask anesthesia with either halothane or sevoflurane in children. METHODS: Sixty-two children, 8 months to 18 years of age, scheduled for minor surgery, were randomly assigned to receive either halothane or sevoflurane. The patients were premedicated with midazolam and anesthesia was induced i.v. with propofol or by inhalation and maintained with halothane or sevoflurane in N2O/O2 via face mask. Recovery was assessed by a "blinded" observer using a postanesthetic recovery score. Agitation and pain were judged using a visual analog scale. The incidence of vomiting was noted. The day after anesthesia older children and parents of younger children were interviewed about their experience of the anesthesia and recovery period. RESULTS: There were no differences between groups in respect of age, weight, length, or duration of surgery or inhalational gas exposure. Median time from end of administration of inhalational agent to spontaneous eye opening was less after sevoflurane (25 min) than after halothane (48 min), (P < 0.01). Likewise, recovery was faster after sevoflurane anesthesia (P < 0.05). Agitation, but not pain, occurred more frequently after sevoflurane than after halothane (P < 0.05) and agitation was significantly more common in younger children. There was no difference in duration of hospital stay between day-care patients in the two groups. CONCLUSION: Early postanesthetic agitation and recovery was faster after mask anesthesia with sevoflurane than after halothane. There was a higher incidence of agitation in younger children, without correlation to pain.     

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 micro Meter.     

The anticonvulsant effects of volatile anesthetics on penicillin-induced status epilepticus in cats

Volatile anesthetics may be used to treat status epilepticus when conventional drugs are ineffective. We studied 30 cats to compare the inhibitory effects of sevoflurane, isoflurane, and halothane on penicillin-induced status epilepticus. Anesthesia was induced and maintained with one of the three volatile anesthetics in oxygen. Penicillin G was injected into the cisterna magna, and the volatile anesthetic discontinued. Once status epilepticus was induced (convulsive period), the animal was reanesthetized with 0.6 minimum alveolar anesthetic concentration (MAC) of the volatile anesthetic for 30 min, then with 1.5 MAC for the next 30 min. Electroencephalogram and multiunit activity in the midbrain reticular formation were recorded. At 0.6 MAC, all anesthetics showed anticonvulsant effects. Isoflurane and halothane each abolished the repetitive spike phase in one cat; isoflurane reduced the occupancy of the repetitive spike phase (to 27%+/-22% of the convulsive period (mean +/- SD) significantly more than sevoflurane (60%+/-29%; P < 0.05) and halothane (61%+/-24%; P < 0.05), and the increase of midbrain reticular formation with repetitive spikes was reduced by all volatile anesthetics. The repetitive spikes were abolished by 1.5 MAC of the anesthetics: in 9 of 10 cats by sevoflurane, in 9 of 9 cats by isoflurane, and in 9 of 11 cats by halothane. In conclusion, isoflurane, sevoflurane, and halothane inhibited penicillin-induced status epilepticus, but isoflurane was the most potent. IMPLICATIONS: Convulsive status epilepticus is an emergency state and requires immediate suppression of clinical and electrical seizures, but conventional drugs may be ineffective. In such cases, general anesthesia may be effective. In the present study, we suggest that isoflurane is preferable to halothane and sevoflurane to suppress sustained seizure.     

Multiple-deep-breath inhalation induction with 5% sevoflurane and 67% nitrous oxide: comparison with intravenous injection of propofol

Purpose. To evaluate the clinical characteristics of multiple-deep-breath inhalation induction with sevoflurane and nitrous oxide followed by the same inhalational anesthetics for maintenance, we compared the technique with intravenous propofol anesthesia. Methods. Forty patients scheduled for ophthalmic surgery under general anesthesia with a laryngeal mask airway (LMA) were assigned to two groups. Anesthesia was induced with multiple-deep-breath inhalation of 5% sevoflurane and 67% nitrous oxide in oxygen (group S: n = 20) or intravenous injection of 1% propofol at the rate of 1200 ml·h⁻¹ with spontaneous inhalation of 67% nitrous oxide in oxygen until the patient lost consciousness or received propofol up to 2 mg·kg⁻¹ (group P: n = 20). We attempted to insert an LMA when the patient's jaw relaxation was adequate. We compared induction times, recovery times, occurrence of adverse events, and patient satisfaction between the two groups. Results. The mean time to insertion of the LMA was significantly shorter in group P (209 ± 118 s) than in group S (302 ± 102 s; P < 0.05). The recovery times did not differ significantly between the groups. There were no serious side effects during the induction and recovery period in either group. Significantly more patients in group P than in group S wanted to have the same anesthetic method (90% vs 50%; P < 0.05). Conclusion. Multiple-deep-breath inhalation induction with 5% sevoflurane and 67% nitrous oxide followed by the same inhalational anesthetics for maintenance was safely performed without serious adverse events. However, the induction time was shorter and patient satisfaction was higher in propofol group than in the inhalational group. Received: April 11, 2001 / Accepted: November 6, 2001     

Sevoflurane as a single anesthetic and physostigmine failure to enhance arousal

AIM: Sevoflurane is recommended for inhalational induction of anesthesia. Physostigmine may antagonize general anesthetics. The study investigates sevoflurane as a single anesthetic and its possible antagonism by physostigmine. METHODS: In 60 women scheduled for breast lump excision, anesthesia was induced with 8% sevoflurane. After 3 min of sevoflurane inhalation, a laryngeal mask airway (LMA) was inserted. Anesthesia was maintained with spontaneous ventilation at end tidal sevoflurane 3%. Systolic and diastolic blood pressure, heart rate and end tidal CO(2) were recorded intraoperatively. After skin closure and at end tidal sevoflurane 0.9%, physostigmine 2 mg or normal saline was given. After 2 min systolic, diastolic blood pressure, heart rate and end tidal CO(2) were recorded and sevoflurane was discontinued. Time to eyes opening, LMA removal and verbal response was recorded. Patients were also assessed for orientation, sedation, sitting ability and the 'picking up matches' test at 0, 15 and 30 min after LMA removal. RESULTS: Systolic, diastolic blood pressure and heart rate increased after laryngeal mask placement (P=0.0001, P=0.0001 and P=0.0001, respectively). Orientation, sitting ability and 'picking up' matches were similar in the 2 groups. Sedation at 15 min was less in the control group (P=0.004). CONCLUSIONS: Sevoflurane can be used as a single anesthetic but its recovery is not enhanced by physostigmine.     

Plasma Inorganic Fluoride Concentrations after Sevoflurane Anesthesia in Children

Background: Sevoflurane is degraded in vivo in adults yielding plasma concentrations of inorganic fluoride [Fluorine sup -] that, in some patients, approach or exceed the 50-micro Meter theoretical threshold for nephrotoxicity. To determine whether the plasma concentration of inorganic fluoride [Fluorine sup -] after 1-5 MAC *symbol* h sevoflurane approaches a similar concentration in children, the following study in 120 children scheduled for elective surgery was undertaken.

Methods: Children were randomly assigned to one of three treatment groups before induction of anesthesia: group 1 received sevoflurane in air/oxygen 30% (n = 40), group 2 received sevoflurane in 70% N2 O/30% O2 (n = 40), and group 3 received halothane in 70% N2 O/30% O sub 2 (n = 40). Mapleson D or F circuits with fresh gas flows between 3 and 6 l/min were used. Whole blood was collected at induction and termination of anesthesia and at 1, 4, 6, 12, and 18 or 24 h postoperatively for determination of the [Fluorine sup -]. Plasma urea and creatinine concentrations were determined at induction of anesthesia and 18 or 24 h postoperatively.

Results: The mean (+/-SD) duration of sevoflurane anesthesia, 2.7+/-1.6 MAC *symbol* h (range 1.1-8.9 MAC *symbol* h), was similar to that of halothane, 2.5+/-1.1 MAC *symbol* h. The peak [Fluorine sup -] after sevoflurane was recorded at 1 h after termination of the anesthetic in all but three children (whose peak values were recorded between 4 and 6 h postanesthesia). The mean peak [Fluorine sup -] after sevoflurane was 15.8+/-4.6 micro Meter. The [Fluorine sup -] decreased to < 6.2 micro Meter by 24 h postanesthesia. Both the peak [Fluorine sup -] (r2 = 0.50) and the area under the plasma concentration of inorganic fluoride-time curve (r2 = 0.57) increased in parallel with the MAC *symbol* h of sevoflurane. The peak [Fluorine sup -] after halothane, 2.0+/-1.2 micro Meter, was significantly less than that after sevoflurane (P < 0.0001) and did not correlate with the duration of halothane anesthesia (MAC *symbol* h; r2 = 0.007). Plasma urea concentrations decreased 24 h after surgery compared with preoperative values for both anesthetics (P < 0.01), whereas plasma creatinine concentrations did not change significantly with either anesthetic.     

Oral clonidine premedication reduces minimum alveolar concentration of sevoflurane for laryngeal mask airway insertion in children

BACKGROUNDS: Sevoflurane is widely employed for inhalational induction in children. Clonidine deepens volatile anesthetics and reduces several types of MAC of sevoflurane. Laryngeal mask airway is a useful device for pediatric anesthesia. The aim of the current study was to determine whether oral clonidine premedication can reduce MAC of sevoflurane for an LMA insertion in children. METHODS: Fifty-six ASA physical status I patients (3-11 years) scheduled for general anesthesia were randomly divided into two groups of 28 patients each. One group (clonidine group) received clonidine 4 microg x kg(-1) approximately 100 min before anesthesia, and the other (control) group did not. Anesthesia was induced with sevoflurane. Each concentration of sevoflurane, at which an LMA insertion was attempted, was predetermined according to the modification of Dixon's up-and-down method with 0.25% as a step size and held constant for at least 20 min before the trial. All responses ('movement' or 'no movement') to an LMA insertion were assessed. RESULTS: Minimum alveolar concentration values of sevoflurane for an LMA insertion were lower in the clonidine group (1.31% +/- 0.18% [mean +/- sd]) than in the control group (2.00% +/- 0.16%). Logistic regression analysis revealed that sevoflurane EC95 values were 1.79% and 2.49% in the clonidine and control groups, respectively. CONCLUSIONS: Oral clonidine premedication reduced the MAC (EC50) and EC95 values of sevoflurane for LMA insertion by 38% and 28%, respectively.     

Propofol or sevoflurane for laryngeal mask airway insertion

PURPOSE: Sevoflurane is a volatile anesthetic agent, which combines rapid, smooth inhalational induction of anesthesia with rapid recovery, making it particularly suitable for day case anesthesia. The laryngeal mask airway is often also used in ambulatory anesthesia, with intravenous propofol being the agent of choice for its insertion. Our objective was to compare the conditions for laryngeal mask airway (LMA) insertion obtained by modified vital capacity breath sevoflurane inhalational induction of anesthesia with propofol intravenous induction. METHODS: Eighty-eight patients, aged 18-65 yr, ASA I-II, undergoing general anesthesia for elective surgery were randomized into two groups in a prospective, single-blind study. Patients in Group P (n=44) received 2.5 mg x kg(-1) propofol i.v. and in Group S (n=44) received sevoflurane 8% in nitrous oxide 50% and oxygen. Ventilation was not assisted. Laryngeal mask airway insertion was attempted at one minute intervals from loss of both verbal response and eyelash reflex, by an anesthesiologist unaware of the induction technique. Complications, such as coughing and head movement, were also noted at each attempt. RESULTS: Mean time to successful LMA insertion was 1.3 (1-3) min in P and 2.2 (1-3) min in S, P < 0.05. Eleven patients in Group P, (25%) required additional propofol compared with four (9%) in S, P < 0.05. Incidence of complications was similar in both groups and by 3 min, LMA was successfully inserted in all patients. CONCLUSION: Modified vital capacity breath inhalational induction with sevoflurane 8% is efficient for LMA insertion in most cases, but takes slightly longer than propofol.     

Hemodynamic and organ blood flow responses to halothane and sevoflurane anesthesia during spontaneous ventilation.

This study compared systemic hemodynamic and organ blood flow responses to equipotent concentrations of halothane and sevoflurane during spontaneous ventilation in the rat. The MAC values for halothane and sevoflurane were determined. Cardiac output and organ blood flows were measured using radiolabeled microspheres. Measurements were obtained in awake rats (control values) and at 1.0 MAC halothane or sevoflurane. The MAC values (mean +/- SEM) for halothane and sevoflurane were 1.10% +/- 0.05% and 2.40% +/- 0.05%, respectively. The PaCO2 increased to a similar extent in both groups compared with control values. During halothane anesthesia, heart rate decreased by 12% (P < 0.01), cardiac index by 26% (P < 0.01), and mean arterial blood pressure by 18% (P < 0.01) compared with control values. Stroke volume index and systemic vascular resistance did not change. During sevoflurane anesthesia, hemodynamic variables remained unchanged compared with control values. Coronary blood flow decreased by 21% (P < 0.01) and renal blood flow by 18% (P < 0.01) at 1.0 MAC halothane, whereas both remained unchanged at 1.0 MAC sevoflurane. Cerebral blood flow increased to a greater extent with halothane (63%; P < 0.01) than with sevoflurane (35%; P < 0.05). During halothane anesthesia, hepatic arterial blood flow increased by 48% (P < 0.01), whereas portal tributary blood flow decreased by 28% (P < 0.01). During sevoflurane anesthesia, hepatic arterial blood flow increased by 70% (P < 0.01) without a concomitant reduction in portal tributary blood flow. Total liver blood flow decreased only with halothane (16%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Preservation of the Ratio of Cerebral Blood Flow/Metabolic Rate for Oxygen during Prolonged Anesthesia with Isoflurane, Sevoflurane, and Halothane in Humans

Background: In several animal studies, an increase in cerebral blood flow (CBF) produced by volatile anesthetics has been reported to resolve over time during prolonged anesthesia. It is important to investigate whether this time-dependent change of CBF takes place in humans, especially in clinical situations where surgery is ongoing under anesthesia. In this study, to evaluate the effect of prolonged exposure to volatile anesthetics (isoflurane, sevoflurane, and halothane), the CBF equivalent (CBF divided by cerebral metabolic rate for oxygen (CMRO2)) was determined every 20 min during anesthesia lasting more than 4 h in patients.

Methods: Twenty-four surgical patients were assigned to three groups at random to receive isoflurane, sevoflurane, or halothane (8 patients each). End-tidal concentration of the selected volatile anesthetic was maintained at 0.5 and 1.0 MAC before surgery and then 1.5 MAC for the 3 h of surgical procedure. Normothermia and normocapnia were maintained. Mean arterial blood pressure was kept above 60 mmHg, using phenylephrine infusion, if necessary. CBF equivalent was calculated every 20 min as the reciprocal of arterial-jugular venous oxygen content difference.

Results: CBF equivalent at 0.5 MAC of isoflurane, halothane, and sevoflurane was 21+/-4, 20+/-3, and 21+/-5 ml blood/ml oxygen, respectively. All three examined volatile anesthetics significantly (P < 0.01) increased CBF equivalent in a dose-dependent manner (0.5, 1.0, 1.5 MAC). At 1.5 MAC, the increase of CBF equivalent with all anesthetics was maintained increased with minimal fluctuation for 3 h. The mean value of CBF equivalent at 1.5 MAC in the isoflurane group (45+/-8) was significantly (P < 0.01) greater than those in the halothane (32+/-8) and sevoflurane (31+/-8) groups. Electroencephalogram was found to be relatively unchanged during observation periods at 1.5 MAC.     

Induction and emergence in infants less than 60 weeks post-conceptual age: comparison of thiopental, halothane, sevoflurane and desflurane

We have studied 40 infants with a post-conceptual age of less than 60 weeks undergoing general anaesthesia for herniotomy. Patients were anaesthetized with 1 MAC equivalent values for age and agent and allocated randomly to receive halothane, savoflurane or thiopental for induction, and halothane, sevoflurane or desflurane for maintenance of anaesthesia. At induction, both time to acceptance of a face mask and loss of eyelash reflex were recorded. Emergence times were noted by a blinded observer. Induction and emergence times were similar between the halothane and sevoflurane groups but were consistently shorter in the desflurane group compared with the halothane or sevoflurane groups. There were no problems at extubation or significant apnoea in any group. Induction of anaesthesia in this population was no quicker with sevoflurane than with halothane and the method used for induction did not influence recovery time. Maintenance of anaesthesia with desflurane resulted in a shorter recovery time in infants in whom anaesthesia was induced with halothane or thiopental. Desflurane maintenance may be particularly beneficial in the neonate.      

Sevofluran in der Kinderanästhesie Maligne Hyperthermie

Inhalational anaesthesia is the most common anaesthesia technique in paediatric anaesthesia worldwide. Up to now the standard anaesthetic used is halothane. Because halothane is tolerated in the upper airways without side effects it is well suited for the inhalational induction of anaesthesia. However, halothane exerts side effects on the hepatic and the cardiovascular system. This review focuses on the replacement of halothane by sevoflurane in paediatric anaesthesia. Apart from its favorable pharmacological properties sevoflurane is also superior because of economical considerations. The following conclusions are drawn: (1) Halothane and sevoflurane do not cause irritations of the airways and are thus suitable for an inhalational induction. Sevoflurane should be administered in oxygen/nitrous oxide during induction of anaesthesia to reduce excitation. (2) The MAC values of sevoflurane are age dependent. In contrast to adult patients the MAC values of sevoflurane are only decreased by 20 to 25% in paediatric patients. The end-tidal concentration of sevoflurane necessary for intubation or insertion of a laryngeal mask is 2 to 4 Vol.%. (3) The blood/gas partition coefficient of sevoflurane is low, resulting in shorter induction times with sevoflurane compared to halothane. The so called priming technique with 8 Vol.% of sevoflurane results in shorter induction times. Consequently, times to recovery and psycho-motor functions are favourable for sevoflurane compared to halothane in paediatric patients. However, shorter recovery times lead to earlier perception of postoperative pain, requiring adequate pain management. (4) The hemodynamic stability after administration of sevoflurane is favourable to that after halothane in paediatric patients, leading to significantly less bradycardia. (5) In paediatric patients no negative effects on kidney function have been observed after administration of sevoflurane. There is no scientific basis for organotoxic effects, thus sevoflurane is suitable for low-flow and minimal-flow anaesthesia. (6) The duration of the action of muscle relaxants is increased to a greater extent in presence of sevoflurane compared to halothane. Consequently, the total dose of muscle relaxants can be reduced using sevoflurane. (7) Similar to the established inhalational anaesthetics sevoflurane triggers malignant hyperthermia (MH) and must not be used in patients in which MH is suspected or in which a predisposition for MH is known.     

Anesthetic modulation of myocardial ischemia and reperfusion injury in pigs: comparison between halothane and sevoflurane

PURPOSE: Halothane offers protection against the reperfusion injury of the myocardium. This study compared sevoflurane with halothane in its potential to modulate the effects of acute severe ischemia and reperfusion on the myocardium. METHODS: Experiments were conducted on 25 pigs. Anesthesia consisted of thiopental, vecuronium and fentanyl. The lungs were mechanically ventilated with oxygen and nitrogen. Animals were randomly allocated to receive either I MAC halothane or sevoflurane. A control group received fentanyl and pentobarbital. Regional myocardial function was measured with sonomicrometers. The left anterior descending coronary artery was occluded for 15 min followed by 60 min reperfusion. RESULTS: Neither halothane nor sevoflurane protected the heart against the effects of acute and severe regional myocardial ischemia. During reperfusion, 89% of the animals receiving sevoflurane suffered from ventricular fibrillation compared with 30% in the halothane group (P < 0.005). Five minutes into the reperfusion period the animals subjected to halothane anesthesia demonstrated an 88% recovery in regional myocardial systolic function while in the sevoflurane group the recovery was 40% of pre-ischemic control (P < 0.05). CONCLUSION: Halothane is associated with less reperfusion arrhythmias and, in addition, recovery of regional myocardial function during reperfusion was more rapid in the presence of halothane than with sevoflurane.     

Comparison of the effects of sevoflurane and halothane on the quality of anaesthesia and serum glutathione transferase alpha and fluoride in paediatric patients

We have compared sevoflurane and halothane anaesthesia in paediatricpatients with reference to induction and recovery. We also assessedhepato-cellular integrity by measurement of serum gluta-thionetransferase alpha (GSTA) concentration and sevoflurane metabolismby serum fluoride concentration. Fifty unpremedicated 5–12-yr-oldchildren were allocated randomly to induction of anaesthesiavia a face mask with 66% nitrous oxide in oxygen and sevoflurane(up to 7%) or halothane (up to 3.5%). Anaesthesia was maintainedfor 1.8 h at 1–1.2 MAC of the volatile agent. Childrenreceiving sevoflurane had significantly faster induction andrecovery variables than those receiving halothane. There wasa small postanaesthetic increase in GSTA in both groups, suggestingthat halothane and sevoflurane may disturb hepato-cellular integrity.Serum concentrations of fluoride were significantly greaterafter sevoflurane than after halothane anaesthesia. There wereno clinical signs or symptoms of hepatic or renal disturbance.Children tolerated sevoflurane better than halothane, whichmay have been because of the non-pungency of sevoflurane andthe rapid psycho-motor recovery after anaesthesia.     

Recovery characteristics of sevoflurane or halothane for day-case anaesthesia in children aged 1-3 years

BACKGROUND: Our objective was to compare the recovery characteristics of sevoflurane and halothane for short day-case anaesthesia in a specifically limited age group of children 1-3 yr. METHODS: Eighty unpremedicated children undergoing day-case adenoidectomy were randomly assigned to receive inhalational induction with either sevoflurane 8% or halothane 5% and nitrous oxide in oxygen (70/30) via a face mask. Tracheal intubation was performed without a muscle relaxant. Anaesthesia was continued with the volatile anaesthetic, adjusted to maintain heart rate and blood pressure within +/-20% of initial values. Recovery was evaluated using a modified Aldrete score, a Pain/Discomfort scale and by measuring recovery end-points. A postoperative questionnaire was used to determine the well-being of the child at home until 24 h after discharge. RESULTS: Emergence and interaction occurred significantly earlier after sevoflurane than halothane but discharge times were similar. More children in the sevoflurane group achieved full Aldrete scores within the first 30 min after anaesthesia, although this group suffered more discomfort during the first 10 min. The amount of postoperative analgesic administered was higher and the first dose given earlier in the sevoflurane group. Postoperative vomiting was more common with halothane, but side-effects in the two groups were otherwise similar in the recovery room and at home. CONCLUSIONS: In children 1-3 yr, sevoflurane provided more rapid early recovery but not discharge after anaesthesia of <30-min duration. Apart from more vomiting with halothane and more discomfort during the first 10 min after awakening with sevoflurane, the quality of recovery was similar with the two anaesthestics.     

The effects of sevoflurane, halothane, enflurane, and isoflurane on hepatic blood flow and oxygenation in chronically instrumented greyhound dogs.

Inhalational anesthetics produce differential effects on hepatic blood flow and oxygenation that may impact hepatocellular function and drug clearance. In this investigation, the effects of sevoflurane on hepatic blood flow and oxygenation were compared with those of enflurane, halothane, and isoflurane in ten chronically instrumented greyhound dogs. Each dog randomly received enflurane, halothane, isoflurane, and sevoflurane, each at 1.0, 1.5, and 2.0 MAC concentrations. Mean arterial blood pressure and cardiac output decreased in a dose-dependent fashion during all four anesthetics studied. Heart rate increased compared to control during enflurane, isoflurane, and sevoflurane anesthesia and did not change during halothane anesthesia. Hepatic arterial blood flow and portal venous blood flow were measured by chronically implanted electromagnetic flow probes. Hepatic O2 delivery and consumption were calculated after hepatic arterial, portal venous, and hepatic venous blood gas analysis. Hepatic arterial blood flow was maintained with sevoflurane and isoflurane. Halothane and enflurane reduced hepatic arterial blood flow during all anesthetic levels compared to control (P less than 0.05), with marked reductions occurring with 1.5 and 2.0 MAC halothane concomitant with an increase in hepatic arterial vascular resistance. Portal venous blood flow was reduced with isoflurane and sevoflurane at 1.5 and 2.0 MAC. A somewhat greater reduction in portal venous blood flow occurred during 2.0 MAC sevoflurane (P less than 0.05 compared to control and 1.0 MAC values for sevoflurane). Enflurane reduced portal venous blood flow at 1.0, 1.5, and 2.0 MAC compared to control. Halothane produced the greatest reduction in portal venous blood flow (P less than 0.05 compared to sevoflurane).(ABSTRACT TRUNCATED AT 250 WORDS)     

Similar haemodynamic, respiratory and metabolic changes with the use of sevoflurane or halothane in children breathing spontaneously via a laryngeal mask airway

BACKGROUND: In preschool children, short-lasting surgical procedures are often performed under combined inhalational and regional anaesthesia with the child breathing spontaneously via a laryngeal mask airway (LMA). Despite widespread use, only limited data are available on haemodynamic, respiratory and metabolic effects of sevoflurane and halothane during LMA anaesthesia. METHODS: In an open-label, randomised, controlled study, 49 children (aged 3-8 years) were allocated to receive either sevoflurane or halothane in 60% nitrous oxide. After insertion of the LMA, end-tidal concentrations of sevoflurane or halothane were maintained at 1 MAC with the child ventilating spontaneously throughout the entire procedure. Analgesia was provided by caudal block. Haemodynamic and respiratory parameters were recorded, and capillary blood-gas samples were obtained repeatedly. RESULTS: Changes in heart rate (HR) and systolic blood pressure were similar in both groups during all observed periods, apart from a significantly higher increase in HR during inhalational induction with sevoflurane (P<0.05). Regression slope analysis during anaesthesia revealed a decrease of the respiratory rate of 5 breaths h-1 (P<0.001) and an increase of end-tidal PCO2 and capillary PCO2 of about 0.25 kPa h-1 (P<0.001), with no significant difference between the two groups. Base excess, calculated in capillary blood gas samples, did not change over time (P>0.5) in either group. CONCLUSIONS: The use of approximately 1 MAC sevoflurane or halothane in 60% N2O in children breathing spontaneously via LMA resulted in comparable haemodynamic, respiratory and metabolic changes, and clinically relevant deteriorations did not occur during the 65-min study period.     

Sustained prolongation of the QTc interval after anesthesia with sevoflurane in infants during the first 6 months of life

BACKGROUND: Sevoflurane, an inhalational anesthetic frequently administered to infants, prolongs the QT interval of the electrocardiogram in adults. A long QT interval resulting in fatal arrhythmia may also be responsible for some cases of sudden death in infants. As the QT interval increases during the second month of life and returns to the values recorded at birth by the sixth month, we evaluated the effect of sevoflurane on the QT interval during and after anesthesia in this particular population. METHODS: In this prospective two-group trial we examined pre-, peri-, and postoperative electrocardiograms of 36 infants aged 1 to 6 months scheduled for elective inguinal or umbilical hernia repair. Anesthesia was induced and maintained with either sevoflurane, or the well-established pediatric anesthetic halothane. Heart rate corrected (c) QTc and JTc interval (indicator of intraventricular conduction delays) were recorded from electrocardiograms before and during anesthesia, and at 60 min after emergence from anesthesia. RESULTS: Prolonged QTc was observed during sevoflurane anesthesia (mean [+/-SD], 473 +/- 19 ms, P< 0.01). Sixty minutes after emergence from anesthesia, QTc was still prolonged (433 +/- 15 ms) in infants treated with sevoflurane compared with those treated with halothane (407 +/- 33 ms, P< 0.01). Analogous differences were found for the JTc interval. CONCLUSIONS: Despite a shorter elimination time than better known inhalational anesthetics, sevoflurane induction and anesthesia results in sustained prolongations of QTc and JTc interval in infants in the first 6 months of life. Electrocardiogram monitoring until the QTc interval has returned to preanesthetic values may increase safety after sevoflurane anesthesia.     

The effect of caudal analgesia on emergence agitation in children after sevoflurane versus halothane anesthesia

Sevoflurane anesthesia in young children has been associated with an increased incidence of emergence agitation compared with halothane. Postoperative pain may be an etiologic factor. We designed a study to compare the incidence of emergence agitation after halothane and sevoflurane anesthesia in children whose pain was managed with caudal analgesia. Eighty children undergoing inguinal hernia repair between the ages of 12 mo and 6 yr were randomly assigned to receive either halothane or sevoflurane anesthesia. Baseline preoperative anxiety was assessed with the Yale Preoperative Anxiety Scale. The children were sedated with oral midazolam, underwent a mask induction, and had a caudal block placed for postoperative analgesia. After surgery, the children's behavior was assessed with a four-point agitation scale. At 5 min after arrival in the postanesthesia care unit (PACU), sevoflurane was associated with a greater incidence of emergence agitation than halothane (26% vs 6%; P < 0.05), but not during the remainder of the PACU stay. Higher levels of preoperative anxiety were associated with difficult mask induction, agitation on admission to the PACU, and more severe agitation episodes. Emergence agitation appears to be an early and transient phenomenon after sevoflurane anesthesia in children with effective postoperative analgesia. IMPLICATIONS: Effective postoperative analgesia may reduce the incidence of emergence agitation reported with sevoflurane anesthesia. The Yale Preoperative Anxiety Scale appears to be helpful in identifying young children who are at risk for developing emergence agitation.     

The minimum alveolar concentration (MAC) and hemodynamic effects of halothane, isoflurane, and sevoflurane in newborn swine

To determine the minimum alveolar concentration (MAC) and hemodynamic responses to halothane, isoflurane, and sevoflurane in newborn swine, 36 fasting swine 4-10 days of age were anesthetized with one of the three volatile anesthetics in 100% oxygen. MAC was determined for each swine. Carotid artery and internal jugular catheters were inserted and each swine was allowed to recover for 48 h. After recovery, heart rate (HR), systemic systolic arterial pressure (SAP), and cardiac index (CI) were measured awake and then at 0.5, 1.0, and 1.5 MAC of the designated anesthetic in random sequence. The (mean +/- SD) MAC for halothane was 0.90 +/- 0.12%; the MAC for isoflurane was 1.48 +/- 0.21%; and the MAC for sevoflurane was 2.12 +/- 0.39%. Awake (mean +/- SD) measurements of HR, SAP, and CI did not differ significantly among the three groups. Compared to the awake HR, the mean HR decreased 35% at 1.5 MAC halothane (P less than 0.001), 19% at 1.5 MAC isoflurane (P less than 0.005), and 31% at 1.5 MAC sevoflurane (P less than 0.005). Compared to awake SAP, mean SAP measurements decreased 46% at 1.5 MAC halothane (P less than 0.001), 43% at 1.5 MAC isoflurane (P less than 0.001), and 36% at 1.5 MAC sevoflurane (P less than 0.005). Mean SAP at 1.0 and 1.5 MAC halothane and isoflurane were significantly less than those measured at equipotent concentrations of sevoflurane (P less than 0.005). Compared to awake CI, mean CI measurements decreased 53% at 1.5 MAC halothane (P less than 0.001) and 43% at 1.5 MAC isoflurane (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)