Raafat S. Hannallah

Comparison of emergence and recovery characteristics of sevoflurane, desflurane, and halothane in pediatric ambulatory patients.

This study compares the emergence and recovery characteristics of sevoflurane, desflurane, and halothane in children undergoing adenoidectomy with bilateral myringotomy and the insertion of tubes.Eighty children 1-7 yr of age were studied. Thirty minutes prior to the induction of anesthesia, all patients received 0.5 mg/kg midazolam orally. Patients were randomly assigned to one of four groups: Group 1, sevoflurane induction and maintenance (S:S); Group 2, halothane induction and sevoflurane maintenance (H:S); Group 3, halothane induction and maintenance (H:H); or Group 4, halothane induction and desflurane maintenance (H:D). Tracheal intubation was facilitated with the use of a single dose of 0.2 mg/kg mivacurium. A Mapelson D circuit was used, and all patients received N2 O:O2 60:40 for induction and maintenance at standardized appropriate fresh gas flow. Ventilation was controlled to maintain normocapnia. End-tidal concentration of anesthetics was maintained at approximately 1.3 minimum alveolar anesthetic concentration (MAC) (halothane: 0.56; sevoflurane: 2.6; desflurane: 8.3) until the end of surgery when all anesthetics were discontinued. Emergence (extubation), recovery (Steward score 6), and discharge times were compared among patients in the four groups using analysis of variance and Newman-Keuls tests. P < 0.05 was considered significant. There were no significant differences among the four groups with respect to age, weight, duration of surgery, or duration of anesthesia. Emergence and recovery from anesthesia were significantly faster in the desflurane group (Group 4) compared with the sevoflurane and halothane groups (Groups 1, 2, and 3) (5 +/- 1.6 min vs 11 +/- 3.7, 11 +/- 4.0, 10 +/- 4.0 min and 11 +/- 3.9 min vs 17 +/- 5.5, 19 +/- 7.1, 21 +/- 8.5 min, respectively). There was a significantly greater incidence of postoperative agitation and excitement in patients who received desflurane (55%) versus sevoflurane (10%) and halothane (25%). There were no significant differences among the four groups with respect to the time to meet home discharge criteria (134 +/- 36.9, 129 +/- 53.3, 117 +/- 64.6, 137 +/- 22.6 in Groups 1, 2, 3, and 4, respectively), in the time to drink oral fluids (139 +/- 31.6, 136 +/- 53.8, 123 +/- 65.0, 142 +/- 29.4 min, respectively), or in the incidence of postoperative vomiting. It is concluded that, although desflurane resulted in the fastest early emergence from anesthesia, it was associated with a greater incidence of postoperative agitation. Sevoflurane resulted in similar emergence and recovery compared with halothane. Desflurane and sevoflurane did not result in faster discharge times than halothane in this patient population. (Anesth Analg 1996;83:917-20)

Postoperative apnea in former preterm infants: prospective comparison of spinal and general anesthesia.

Thirty-six former preterm infants undergoing inguinal hernia repair were studied. All were less than or equal to 51 weeks postconceptual age at the time of operation. Patients were randomly assigned to receive general or spinal anesthesia. Group 1 patients received general inhalational anesthesia with neuromuscular blockade. Group 2 patients received spinal anesthesia using 1% tetracaine 0.4-0.6 mg/kg in conjunction with an equal volume of 10% dextrose and 0.02 ml epinephrine 1:1000. In the first part of the study, infants randomized to receive spinal anesthesia also received sedation with im ketamine 1-2 mg/kg prior to placement of the spinal anesthetic (group 2 A). The remainder of group 2 patients did not receive sedation (group 2 B). Respiratory pattern and heart rate were monitored using an impedance pneumograph for at least 12 h postoperatively. Tracings were analyzed for evidence of apnea, periodic breathing and/or bradycardia by a pulmonologist unaware of the anesthetic technique utilized. None of the patients who received spinal anesthesia without ketamine sedation developed postoperative bradycardia, prolonged apnea, or periodic breathing. Eight of nine infants (89%) who received spinal anesthesia and adjunct intraoperative sedation with ketamine developed prolonged apnea with bradycardia. Two of the eight infants had no prior history of apnea. Five of the 16 patients (31%) who received general anesthesia developed prolonged apnea with bradycardia. Two of these five infants had no prior history of apnea. When infants with no prior history of apnea were analyzed separately, there was no statistically significant increased incidence of apnea in children receiving general versus spinal anesthesia with or without ketamine sedation. Because of the small numbers of patients studied, and the multiple factors that may influence the incidence of postoperative apnea (e.g., prior history of neonatal apnea), standard postoperative respiratory monitoring of these high-risk infants is still recommended following all anesthetic techniques.

Induction and maintenance characteristics of anesthesia with desflurane and nitrous oxide in infants and children.

To determine the induction and maintenance characteristics of desflurane in pediatric patients, the authors anesthetized 206 infants and children aged 1 month to 12 yr with nitrous oxide plus desflurane and/or halothane in oxygen. Patients were assigned to one of four groups: anesthesia was 1) induced and maintained with desflurane after premedication with an oral combination of meperidine, diazepam, and atropine; 2) induced and maintained with desflurane; 3) induced with halothane and maintained with desflurane; or 4) induced and maintained with halothane. An unblinded observer recorded time to loss of consciousness (lid reflex), time to intubation, and clinical characteristics of the induction and maintenance of anesthesia. Moderate-to-severe laryngospasm (49%) and moderate-to-severe coughing (58%) occurred frequently during induction of anesthesia with desflurane; the incidence of these was not altered by premedication. In contrast, laryngospasm and coughing were rare during induction of anesthesia with halothane. In unpremedicated patients, time to loss of lid reflex (mean +/- SD) was similar for desflurane (2.4 +/- 1.2 min) and halothane (2.1 +/- 0.8 min). During induction of anesthesia, before laryngoscopy and intubation, mean arterial pressure less than 80% of baseline was more common with halothane; heart rate and mean arterial pressure greater than 120% of baseline were more common with desflurane. Intraoperatively, heart rate greater than 120% of baseline was more common with desflurane; blood pressures were similar for the two anesthetics. The authors conclude that the high incidence of airway complications during induction of anesthesia with desflurane limits its utility for inhalation induction in pediatric patients. Anesthesia can be safely maintained with desflurane if induced with a different anesthetic.

A comparison of three doses of a commercially prepared oral midazolam syrup in children.

Midazolam is widely used as a preanesthetic medication for children. Prior studies have used extemporaneous formulations to disguise the bitter taste of IV midazolam and to improve patient acceptance, but with unknown bioavailability. In this prospective, randomized, double-blinded study we examined the efficacy, safety, and taste acceptability of three doses (0.25, 0.5, and 1.0 mg/kg, up to a maximum of 20 mg) of commercially prepared Versed® syrup (midazolam HCl) in children stratified by age (6 mo to <2 yr, 2 to <6 yr, and 6 to <16 yr). All children were ASA class I–III scheduled for elective surgery. Subjects were continuously observed and monitored with pulse oximetry. Ninety-five percent of patients accepted the syrup, and 97% demonstrated satisfactory sedation before induction. There was an apparent relationship between dose and onset of sedation and anxiolysis (P < 0.01). Eight-eight percent had satisfactory anxiety ratings at the time of attempted separation from parents, and 86% had satisfactory anxiety ratings at face mask application. The youngest age group recovered earlier than the two older age groups (P < 0.001). There was no relationship between midazolam dose and duration of postanesthesia care unit stay. Before induction, there were no episodes of desaturation, but there were two episodes of nausea and three episodes of emesis. At the time of induction, during anesthesia, and in the postanesthesia care unit, there were several adverse respiratory events. Oral midazolam syrup is effective for producing sedation and anxiolysis at a dose of 0.25 mg/kg, with minimal effects on respiration and oxygen saturation even when administered at doses as large as 1.0 mg/kg (maximum, 20 mg) as the sole sedating medication to healthy children in a supervised clinical setting.

The Effect of Intranasal Fentanyl on the Emergence Characteristics After Sevoflurane Anesthesia in Children Undergoing Surgery for Bilateral Myringotomy Tube Placement

Children undergoing placement of bilateral myringotomy tubes (BMT) often exhibit pain-related behavior (agitation) in the postanesthesia care unit. We compared the emergence and recovery profiles of pediatric patients who received sevoflurane with or without supplementary intranasal fentanyl for BMT surgery. By using a prospective, double-blinded design, 150 children 6 mo to 5 yr of age, scheduled for routine BMT surgery, were anesthetized with sevoflurane (2%–3%) in a 60% N2O/O2 gas mixture. Patients were randomized to receive equal volumes of intranasal saline (Control), 1 &mgr;g/kg fentanyl or 2 &mgr;g/kg fentanyl. A blinded observer evaluated each patient using a previously described 4-point agitation scale and the Steward recovery scale. Response to parental presence was observed after a score of six (full recovery) was achieved on the Steward recovery scale. There were no significant differences among the three groups regarding age, weight, surgeon, duration of anesthesia, or ear condition. Recovery times and emergence characteristic scores were not statistically different. Agitation scores were significantly reduced in the 2-&mgr;g/kg Fentanyl group as compared with the Control group (P = 0.012). Fentanyl 2 &mgr;g/kg is recommended to reduce the incidence of agitation seen in these patients.

Circulating endotoxin and tumor necrosis factor during pediatric cardiac surgery.

ObjectivesTo study the hypothesis that endotoxin and tumor necrosis factor-α (TNF) are released into the circulation during the perioperative period in children undergoing open-heart surgery, and to assess the possible role of these factors in postoperative morbidity. DesignProspective study. SettingOperating room and ICU of a childrens hospital. PatientsTwenty-four consecutive patients undergoing open-heart surgery for repair of congenital heart disease. MethodsEndotoxin and TNF concentrations were measured in blood samples withdrawn from patients at predetermined time points in the perioperative period. These concentrations were also measured in samples from all fluids and drugs administered to patients. Clinical variables were measured throughout the perioperative period, and the Pediatric Risk of Mortality score was calculated daily. ResultsAll of the preoperative control samples were negative for endotoxin and TNF. Endotoxin or TNF was detected in the blood of 21 (88%) of 24 patients during or after surgery. Endotoxin (ranging in concentrations from 0.32 to 438 pg/mL) was detected in the blood of 16 (67%) of the 24 patients. The majority of the samples positive for endotoxin were withdrawn during cardiopulmonary bypass and were associated with positive samples from the pump, from cardiotomy suction specimens, and from autotrans-fused blood. Blood cultures of all patients, except one, were negative for bacterial growth. TNF (ranging in concentrations from 3 to 132 U/mL) was detected in the blood of nine (37%) of the 24 patients. Patients positive for TNF had significantly (p < .05) lower mean central venous pressures at 20 hrs after surgery and higher mean heart rates postoperatively compared with patients negative for TNF. No differences in other indicators of perioperative morbidity and intraoperative conditions were found, when the groups positive for endotoxin or TNF were compared with the groups negative for endotoxin or TNF, respectively. ConclusionsEndotoxin and TNF are released into the circulation during and after pediatric open-heart surgery. TNF release may be related to some of the hemodynamic changes observed after open-heart surgery. (Crit Care Med 1992; 20:1090–1096)

The effect of fentanyl on the emergence characteristics after desflurane or sevoflurane anesthesia in children.

Desflurane and sevoflurane anesthesia are associated with emergence agitation in children. In this study, we examined the effect of a single intraoperative dose of fentanyl on emergence characteristics in children undergoing adenoidectomy. One hundred children, 2–7 yr old, were randomly assigned to receive desflurane or sevoflurane for maintenance of general anesthesia after an inhaled induction with sevoflurane and a 2.5 &mgr;g/kg dose of fentanyl. An observer blind-ed to the anesthetic technique assessed the times to achieve emergence, extubation and recovery criteria, as well as emergence behaviors. The results showed a similar incidence of severe emergence agitation after general anesthesia with desflurane (24%) and sevoflurane (18%). Times to achieve extubation and postanesthesia care unit discharge criteria were shorter with desflurane than with sevoflurane. With this technique, desflurane allows for a more rapid emergence and recovery than sevoflurane. In children receiving desflurane or sevoflurane, the concurrent use of fentanyl in a dose of 2.5 &mgr;g/kg results in a small incidence of emergence agitation.

A Comparison Between Bupivacaine Instillation Versus Ilioinguinal/Iliohypogastric Nerve Block for Postoperative Analgesia Following Inguinal Herniorrhaphy in Children

This study compared the postoperative pain relief provided by simple instillation of bupivacaine into a hernia wound with that provided by ilioinguinal/iliohypogastric (IG/IH) nerve block. Sixty children undergoing inguinal hernia repair under general anesthesia were randomized to receive 0.25 ml/kg of 0.25% bupivacaine for either IG/IH nerve block or up to 0.5 ml/kg of the same solution for instillation nerve blocks. In the postanesthesia care unit (PACU), a trained blinded observer evaluated the patients level of postoperative pain using a standardized 10-point objective pain scale. Fentanyl 1-2 micrograms/kg was administered intravenously to any child scoring 6 or more points on the pain scale. The difference in pain scores among the two groups were compared. The two groups were not significantly different in age, duration of surgery, or anesthesia. There was no significant difference between patients who received the two treatment modalities in their pain scores, analgesic requirements in the PACU, recovery times, and discharge times. These results demonstrate that the simple instillation of local anesthetics into a wound provides postoperative pain relief following hernia repair, which is as effective as that provided by intraoperative IG/IH nerve block.

Rapid emergence does not explain agitation following sevoflurane anaesthesia in infants and children: A comparison with propofol

Background: Emergence agitation in children is frequently associated with the use of the new highly insoluble volatile anaesthetics. Rapid emergence has been cited as one of the possible causes. Propofol also permits rapid emergence from general anaesthesia but is not associated with agitation.

Age and the onset of desaturation in apnoeic children

Most patients undergoing general anaesthesia are apnoeic during laryngoscopy and tracheal intubation. This study determined the time until the onset of desaturation following preoxygenation in apnoeic infants, children, and adolescents. Fifty ASA physical status I patients, 2 days to 18 yr of age, were studied. The patients were stratified into one of five groups according to age: Group I, 0–6 mo; Group II, 7–23 mo; Group III 2–5 yr; Group IV, 6–10 yr; and Group V, 11–18 yr. Following induction of anaesthesia with halothane via mask or intravenous barbiturates, the ability of the anaesthetist to ventilate the lungs via the mask was ascertained and paralysis was accomplished with vecuronium 0.1 mg · kg−1. Manual mask ventilation was maintained with oxygen and halothane. When end-tidal N2 decreased below 3% (minimum time two minutes), the face mask was removed. The time between the removal of the face mask and a decrease in oxygen saturation (SpO2 from 99–100% to 90% was measured. Manual ventilation was then resumed and the trachea intubated. Desaturation started earlier in infants than in two-to five-year-old children (96.5 ± 12.7 sec vs 160.4 ± 30.7 sec, P < 0.0001). Children became desaturated faster than adolescents (160.4 ± 30.7 vs 382.4 ± 79.9 sec, P < 0.0001). The time required to reach 90% saturation correlated well with age by linear regression analysis (r2 = 0.88, P < 0.0001). We conclude that the time to onset of desaturation following pre-oxygenation with mask ventilation increases with age in healthy apnoeic children. Adolescents can tolerate apnoea for longer than children, and infants exhibit desaturation faster than children.RésuméLa plupart des patients demeurent en apnée pendant la laryngoscopie et l’intubation. Cette étude précise l’intervalle qui précède la désaturation après préoxygénation chez les nouveaunés, les enfants et les adolescents. Cinquante patients ASA I, âgés de deux jours à dixhuit ans, font partie de l’étude. Les patients sont répartis en cinq groupes selon leur âge: groupe I, 0–6 mois, groupe II, 7–23 mois; groupe III, 2–5 ans; groupe IV, 6–10 ans; groupe V, 11–18 ans. Après une induction au masque à l’halothane ou aux barbituriques intraveineux, l’habileté de ventiler les poumons au masque est constatée et la paralyse initiée avec du vécuronium 0,1 mg · kg−1. La ventilation manuelle au masque est maintenue avec de l’oxygène et de l’halothane. Quand le N2 télé- expiratoire diminue sous 3% (en deux minutes au minimum), le masque est enlevé. On mesure l’intervalle entre le retrait du masque et une baisse de la saturation en oxygène (SpO2 de 99–100% à 90%. On reprend la ventilation manuelle et la trachée est intubée. La désaturation débute plus rapidement dans les deux premiers groupes que chez les enfants de deux à cinq ans (96,5 ± 12,7 s vs 160,4 ± 30,7 s, P< 0,0001). Les enfants désaturent plus rapidement que les adolescents (160,4 ± 30,7 vs 382,4 ± 79,9 s, P < 0,0001). Le temps nécessaire à l’atteindre 90% de désaturation présente une bonne corrélation avec l’âge comme le montre l’analyse de régression linéaire (r2 = 0,88, P < 0,0001). Nous concluons que l’intervalle qui précède la désaturation après la préoxygénation avec ventilation au masque augmente avec l’âge chez les enfants apnéiques en bonne santé. Les adolescents peuvent tolérer l’apnée plus longtemps que les enfants et les nourissons se désaturent plus rapidement que les enfants.