Ramesh I. Patel

Comparison of three techniques for internal jugular vein cannulation in infants

Central venous cannulation allows accurate monitoring of right atrial pressure and infusion of drugs during the anaesthetic management of infants undergoing cardiopulmonary bypass. In this prospective, randomized study, we compared the success and speed of cannulation of the internal jugular vein in 45 infants weighing less than 10 kg using three modes of identification: auditory signals from internal ultrasound (SmartNeedle, SM), external ultrasound imaging (Imaging Method, IM) and the traditional palpation of the carotid pulsation and other landmarks (Landmarks Method, LM). The cannulation time, number of attempts with LM and SM techniques were greater than those with IM technique. The incidence of carotid artery puncture and the success rate were not significantly different among the three groups. In infants, a method based on visual ultrasound identification (IM) of the internal jugular vein is more precise and efficient than methods based on auditory (SM) and tactile perception (LM).

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.

Propofol anaesthesia in paediatric ambulatory patients: a comparison with thiopentone and halothane

The purpose of this study was to evaluate the haemodynamic changes during induction, as well as the speed and quality of recovery when propofol (vs thiopentone and/or halothane) was used for induction and maintenance of anaesthesia in paediatric outpatients. One hundred unmedicated children, 3–12-yr-old, scheduled for ambulatory surgery were studied. The most common surgical procedures performed were eye muscle surgery (42%), plastic surgery (21%), dental restoration (15%), and urological procedures (15%). The children were randomized to an anaesthetic regimen for induction/maintenance as follows: propofol/propofol infusion; propofol/halothane; thiopentone/halothane; halothane for both induction and maintenance. Succinylcholine 1.5 mg · kg−1 was used to facilitate tracheal intubation and N2O/O2 were used as the carrier gases in each case. All maintenance drugs were titrated according to the clinical response of the patient to prevent movement and/or maintain BP ± 20% of baseline. Two patients (4%) who received propofol expressed discomfort during injection. The mean propofol dose required to prevent movement was 267 ± 83 μg · kg−1 · min−1. The overall pattern of haemodynamic changes, as well as awakening (extubation) times were not different among the four groups. Children who received propofol recovered faster (22 vs 29–36 min) (P < 0.05), were discharged home sooner (101 vs 127–144 min) (P < 0.05), and had less postoperative vomiting (4 vs 24–48%) (P < 0.05) than all others. There were no serious complications or adverse postoperative sequelae in any of the patients in the study. It is concluded that induction and maintenance of anaesthesia with propofol is a well-tolerated anaesthetic technique in children, and is associated with faster recovery and discharged as well as less vomiting than when halothane is used.RésuméL’objet de cette étude est d’évaluer les changements hémodynamiques à l’induction ainsi que la vitesse et la qualité du réveil, lorsque le propofol (versus thiopental et/ou halothane) est utilisé pour l’induction et l’entretien de l’anesthésie d’enfants en ambulatoire. On a étudié 100 enfants dépourvus de traitement, entre 3 et 12 ans, programmés pour une chirurgie ambulatoire. Les chirurgies les plus habituelles sont la cure de strabisme (42%), la chirurgie plastique (21%), la restauration dentaire (15%) et les interventions urologiques (15%). Les enfants sont distribués aléatoirement pour une anesthésie d’induction/entretien comme suit: propofol/infusion de propofol; propofol/ halothane; thiopental/halothane; halothane pour l’induction et l’entretien. On a utilisé la succinylcholine 1,5 mg · kg−1 pour faciliter l’intubation trachéale et le N2O/O2 est utilisé comme véhicule gazeux dans tous les cas. Pour l’entretien de l’anesthésie, les agents sont titrés en fonction de la réponse clinique du patient afin de prévoir les mouvements et/ou de maintenir la pression artérielle à ±20% de la valeur de base. Deux patients (4%) ont manifesté un inconfort pendant l’injection de propofol. La dose moyenne de propofol requise pour prévenir le mouvement est de 267 ± 83 μg · kg−1 · min−1. Autant le profil général des variations hémodynamiques que le moment du réveil (extubation) sont identiques dans les quatre groupes. Les enfants qui reçoivent le propofol se réveillent plus vite (22 secondes versus 29–36 min), (P < 0,05) sont renvoyés plus tôt à la maison (101 versus 127–144 min) (P < 0,05) et ont moins de vomissements post-opératoires (4 versus 24–48%) (P < 0,05). Il n’y a pas eu de complications sérieuses ni de séquelles postopératoires chez aucun des patients de l’étude. On en conclut que l’induction et l’entretien de l’anesthésie avec le propofol est une technique bien tolérée chez l’enfant, associée avec un réveil et un départ plus rapides ainsi que des vomissements moindres que lors de l’utilisation d’halothane.

The effects of the simulated Valsalva maneuver, liver compression, and/or Trendelenburg position on the cross-sectional area of the internal jugular vein in infants and young children

UNLABELLED We calculated the effects of the simulated Valsalva (V), liver (L) compression, and Trendelenburg (T) position on the cross-sectional area (CSA) of the right internal jugular vein by using planimetry (Aloka ultrasound machine) in 84 infants and young children. Eight combinations of positions and interventions were studied for each patient, with the patient supine, in the T position, during the simulated V maneuver, with L compression and a combination of maneuvers. Data were analyzed by using Friedmans chi(2) test and Wilcoxons signed rank test. An increase of >25% in the CSA of the internal jugular vein was considered significant. In infants, the maximal mean increase achieved with the combination of all 3 maneuvers was only 17.4% +/- 16.1%. As a single maneuver, the simulated V was the most effective (11.6% +/- 11.5%). In children, the combination of all 3 maneuvers performed simultaneously produced a mean 65.9% (SD +/- 44.7%) increase in the CSA, which was larger than the increase by all other maneuvers alone or in a single combination (Friedmans test, P < 0.001 and Wilcoxons test, P < 0.002). As a single maneuver, V produced the most increase (40.4% +/- 32.2%) compared with L compression (14.3% +/- 18.9%) or T position (24.3% +/- 27.1%). IMPLICATIONS The combinations of simulated Valsalva, liver compression, and Trendelenburg maneuvers produce the maximal mean increase in the size of the internal jugular vein in infants and young children, with the Valsalva maneuver being the most effective single maneuver. This increase is significant in young children, but negligible in infants.

Emergence airway complications in children: a comparison of tracheal extubation in awake and deeply anesthetized patients.

We compared the differences in oxygen saturation and airway-related complications after tracheal extubation in pediatric patients undergoing elective strabismus surgery or adenoidectomy and/or tonsillectomy who were awake versus anesthetized. Seventy otherwise healthy patients between 2 and 8 yr of age were studied. Anesthesia was induced with halothane or thiamylal and maintained with nitrous oxide and halothane. After induction of anesthesia, the patients were randomly assigned to group 1 (awake extubation) or group 2 (anesthetized extubation). Oxygen saturation was measured continuously and recorded 10 min before extubation and at 1, 2, 3, 5, 7, 10, 15, 20, 25, and 30 min after tracheal extubation. Supplemental oxygen was administered when oxygen saturation values were less than 90% while breathing room air. Oxygen saturation levels were higher in group 2 than in group 1 at 1, 2, 3, and 5 min after extubation. There were no differences between the two groups in the number of patients requiring supplemental oxygen. The incidence of airway-related complications such as laryngospasm, croup, sore throat, excessive coughing, and arrhythmias was not different between the two groups. We conclude that the anesthesiologists preference or surgical requirements may dictate the choice of extubation technique in otherwise healthy children undergoing elective surgery.

Fast-tracking children after ambulatory surgery.

This study was designed to determine the feasibility and benefits of fast-tracking children after ambulatory surgery. One-hundred-fifty-five healthy children undergoing surgical procedures lasting <90 min were studied in a randomized manner. After surgery, children who met predefined recovery criteria in the operating room were entered into one of the study groups. Seventy-one patients (control) were first admitted to the postanesthesia care unit (PACU) and then to the second-stage recovery unit (SSRU). Eighty-four children bypassed the PACU and were directly admitted to the SSRU (Fast-Track group). The demographic data, airway management, and surgical procedures were similar in both groups of patients. During the recovery phase, 62.0% of the PACU group patients and 40.5% of the Fast-Track patients received analgesics (P = 0.01). The total recovery time was 79.1 ± 48.3 min in the Fast-Track group and 99.4 ± 48.6 min in the Control group (P = 0.008). A larger percentage of parents in the Fast-Track group (31% vs 16%) reported that their child was restless on arrival at the SSRU (P = 0.037). There were no clinically significant adverse events. However, adequate pain control must be provided before transfer to SSRU. In conclusion, fast-tracking children after ambulatory surgery is feasible and beneficial when specific selection criteria are used.

Single-Dose Ondansetron Prevents Postoperative Vomiting in Pediatric Outpatients

This randomized, double-blind, parallel-group, multicenter study evaluated the safety and efficacy of ondansetron (0.1 mg/kg to 4 mg intravenously) compared with placebo in the prevention of postoperative vomiting in 429 ASA status I-III children 1-12 yr old undergoing outpatient surgery under nitrous oxide- and halothane-based general anesthesia. The results show that during both the 2-h and the 24-h evaluation periods after discontinuation of nitrous oxide, a significantly greater percentage of ondansetron-treated patients (2 h 89%, 24 h 68%) compared with placebo-treated patients (2 h 71%, 24 h 40%) experienced complete response (i.e., no emetic episodes, not rescued, and not withdrawn; P < 0.001 at both time points). Ondansetron-treated patients reached criteria for home readiness one-half hour sooner than placebo-treated patients (P < 0.05). The age of the child, use of intraoperative opioids, type of surgery, and requirement to tolerate fluids before discharge may also have affected the incidence of postoperative emesis during the 0- to 24-h observation period. Use of postoperative opioids did not have any effect on complete response rates in this patient population. We conclude that the prophylactic use of ondansetron reduces postoperative emesis in pediatric patients, regardless of the operant influential factors. Implications: Postoperative nausea and vomiting often occur after surgery and general anesthesia in children and are the major reason for unexpected hospital admission after ambulatory surgery. Our study demonstrates that the prophylactic use of a small dose of ondansetron reduces postoperative vomiting in pediatric patients. (Anesth Analg 1997;85:538-45)

Low-dose Intramuscular Ketamine for Anesthesia Pre-induction in Young Children Undergoing Brief Outpatient Procedures

The authors sought to determine whether intramuscular ketamine (2 mg/kg) would facilitate inhaled induction of anesthesia in those children who are uncooperative. Thirty-five children were anesthetized with halothane and nitrous oxide for insertion of tympanotomy tubes. Twenty of those children were deemed by the anesthesiologist to be uncooperative and received 2 mg/kg of ketamine im prior to induction of anesthesia. The onset time (time from ketamine administration until induction of inhaled anesthesia could be started) was 2.7 +/- 0.3 min. The quality of the subsequent acceptance of inhaled induction with halothane was excellent in 61% of the patients and adequate in the remaining 39%. The recovery and discharge times were compared with those observed in 15 matched children who accepted induction of anesthesia via a mask without the use of ketamine. Recovery time was not prolonged, but home discharge was delayed by an average of 13 min in the ketamine group (P less than 0.04). Low-dose im ketamine was found to be an acceptable pre-induction drug in young children who are uncooperative for an inhaled induction of anesthesia.

Recovery scores do not correlate with postoperative hypoxemia in children.

The correlation between the degree of postanesthetic recovery (PAR) in children as measured by a modified Aldrete scoring system and oxygen saturation (Sao2) wasstudied. Eighty-one ASA PS I unpremedicated infants and children were studied. Oxygen saturation and PAR scores were recorded on arrival in the recovery room, then at 5-minute-intervals. Patients with Sao2 > 95% were given supplemental oxygen. The proportion of children with Sao2 > 95% and ≥95% was not significantly differentamong patients with low PAR scores (≤6) and those with high scores (7–10) in any agegroup. Similarly, the magnitude of Sao, increase after oxygen supplementation did not seem to correlate with increasing wakefulness; i.e., higher PAR scores. It is concluded that children recovering from anesthesia can become hypoxemic in the recovery room. Thedegree of wakefulness as measured by a PAR score cannot be used to establish an end point for oxygen supplementation. Oxygen supplementution and/or Sao, monitoring are recommended in all children recovering from anesthesia.

Testing anal sphincter tone predicts the effectiveness of caudal analgesia in children.

In this study, we examined the effectiveness of caudal blocks and correlated it with the laxity of the patients’ anal sphincter before emergence from anesthesia in 178 children undergoing inguinal and/or penile surgery. Bupivacaine 0.25% in a volume of 0.6–1.25 mL/kg was used in all patients. The presence of a lax anal sphincter at the end of surgery correlated significantly with the reduced administration of narcotics intraoperatively and in the postanesthesia care unit (P < 0.001). The sensitivity of the sphincter tone test was 98.1% with a 95% confidence interval (CI) ranging from 94.3% to 99.6%. The specificity of the test was 94.4% with a 95% CI of 72.0%–100%. The positive predictive value of this test in predicting adequate caudal block was excellent (99.4%) with a 95% CI of 96.1%–100%. The negative predictive value was better than average (85%) with a 95% CI of 62.9%–95.4%. We conclude that a lax anal sphincter can predict the effectiveness of analgesia after pediatric caudal blockade. A tight sphincter may suggest the need to repeat the block before the child awakens, or consider alternate methods of postoperative analgesia.