Publications (14)49.94 Total impact
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Article: The anesthesiologist's role assessing the individual patient's risk/benefit.
Anesthesia and analgesia 02/2012; 114(2):476; author reply 476-7. · 3.08 Impact Factor -
Article: Fentanyl does not reduce the incidence of laryngospasm in children anesthetized with sevoflurane.
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ABSTRACT: The modifying effects of fentanyl on protective airway reflexes have not been characterized in children. The aim of this study was to assess the impact of increasing doses of fentanyl on laryngeal reflex responses in children anesthetized with sevoflurane. The authors hypothesized that the incidence of laryngospasm evoked by laryngeal stimulation is reduced with increasing doses of fentanyl. Sixty-three children, aged 2-6 yr, scheduled for elective surgery, were anesthetized with sevoflurane (1 minimum alveolar concentration). By using an established technique, laryngeal and respiratory responses were elicited by spraying distilled water on the laryngeal mucosa: (1) before the administration of fentanyl, (2) after the administration of 1.5 microg/kg fentanyl, and (3) after the administration of a second dose of 1.5 microg/kg fentanyl. In 10 children, serving as a time control, three successive laryngeal stimulations were performed without the administration of fentanyl. The responses were assessed by a blinded reviewer. The study was completed in 60 patients. The incidence of laryngospasm was not reduced when up to two successive doses of 1.5 microg/kg fentanyl were administered. The incidence of laryngospasm lasting for more than 10 s was 26% before receiving fentanyl, 31% after recieving1.5 microg/kg fentanyl, and 18% after receiving a second dose of 1.5 microg/kg fentanyl (P = 0.36 and 0.78, respectively). This response was similar to that observed in the time control group (P = 0.21). Two successive doses of 1.5 microg/kg fentanyl did not effectively prevent laryngospasm in children, aged 2-6 yr, anesthetized with sevoflurane.Anesthesiology 07/2010; 113(1):41-7. · 5.36 Impact Factor -
Article: A deeper level of ketamine anesthesia does not affect functional residual capacity and ventilation distribution in healthy preschool children.
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ABSTRACT: Ketamine is commonly used in children in the emergency setting and while undergoing diagnostic and therapeutic interventions because of its combination of hypnotic and analgesic properties. Although studies comparing various levels of ketamine anesthesia are lacking, previous work suggests that lung mechanics might only be minimally affected by ketamine. After approval from the Ethics Committee, anesthesia was induced with 2 mg.kg(-1) racemic ketamine followed by a continuous infusion of ketamine 2 mg.kg(-1) h(-1) (level I) in 26 children (2-6 years of age), and after 5 min, the first set of measurements was performed. Then, a second bolus of ketamine 2 mg.kg(-1) followed by ketamine 4 mg.kg(-1) h(-1) was administered (level II) and after 5 min, the second set of measurements was performed. Functional residual capacity (FRC) and lung clearance index (LCI) were calculated using a multibreath analysis by a blinded observer. Functional residual capacity and LCI did not change between the two levels (FRC 25.6 [4.3] ml.kg(-1) vs 25.5 [4.2] ml.kg(-1), P=0.769, LCI 10.5 [1.2] vs 10.3 [1.1], P=0.403). The minute ventilation was similar between the two levels of anesthesia. The University of Michigan Sedation Scale increased from 3 (3) to 4 (3-4) at the second level of ketamine anesthesia. A deeper level of anesthesia induced by ketamine does not affect FRC, ventilation distribution or minute ventilation suggesting that the depth of ketamine anesthesia has a minimal effect on pulmonary function.Pediatric Anesthesia 01/2008; 17(12):1150-5. · 2.10 Impact Factor -
Article: Prone equals prone? Impact of positioning techniques on respiratory function in anesthetized and paralyzed healthy children.
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ABSTRACT: Although the prone position is effectively used to improve oxygenation, its impact on functional residual capacity is controversial. Different techniques of body positioning might be an important confounding factor. The aim of this study was to determine the impact of two different prone positioning techniques on functional residual capacity and ventilation distribution in anesthetized, preschool-aged children. Functional residual capacity and lung clearance index, a measure of ventilation homogeneity, were calculated using a sulfur-hexafluoride multibreath washout technique. After intubation, measurements were taken in the supine position and, in random order, in the flat prone position and the augmented prone position (gel pads supporting the pelvis and the upper thorax). Pediatric anesthesia unit of university hospital. Thirty preschool children without cardiopulmonary disease undergoing elective surgery. Mean (range) age was 48.5 (24-80) months, weight 17.2 (10.5-26.9) kg, functional residual capacity (mean +/- SD) 22.9+/- 6.2 ml.kg (-1) in the supine position and 23.3 +/- 5.6 ml.kg (-1) in the flat prone position, while lung clearance indices were 8.1 +/- 2.3 vs. 7.9 +/- 2.3, respectively. In contrast, functional residual capacity increased to 27.6 +/- 6.5 ml.kg (-1) (p< 0.001) in the augmented prone position while at the same time the lung clearance index decreased to 6.7 +/- 0.9 (p< 0.001). Functional residual capacity and ventilation distribution were similar in the supine and flat prone positions, while these parameters improved significantly in the augmented prone position, suggesting that the technique of prone positioning has major implications for pulmonary function.Intensive Care Medicine 10/2007; 33(10):1771-7. · 5.40 Impact Factor -
Article: Decrease in functional residual capacity and ventilation homogeneity after neuromuscular blockade in anesthetized preschool children in the lateral position.
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ABSTRACT: While functional residual capacity (FRC) is reduced in children undergoing general anesthesia, the lateral position leads to an increase in FRC compared with the supine position. The impact of neuromuscular blockade remains unknown. We tested the hypothesis that neuromuscular blockade leads to a decrease in FRC and increase in lung clearance index (LCI) while the application of positive endexpiratory pressure (PEEP) of 6 cmH(2)O leads to a restoration in both parameters. After approval of the local Ethics Committee, we studied 18 preschool children (2-6 years) without cardiopulmonary disease, who were scheduled for elective surgery. Anesthesia was standardized using propofol and fentanyl. FRC and LCI were calculated by a blinded observer using a SF6 multibreath washout technique with an ultrasonic transit-time airflow meter (Exhalyzer D). Measurements were taken in the left lateral position (PEEP 3 cmH2O) after 1. intubation with a cuffed tracheal tube, 2. neuromuscular blockade with rocuronium, and 3. the additional application of PEEP (6 cmH2O). Functional residual capacity mean (sd) decreased from 31.6 (4.4) ml.kg(-1) to 27.6 (4.2) ml.kg(-1) (P<0.001) following neuromuscular blockade while the LCI increased from 6.54 (0.6) to 7.0 (0.6) (P<or=0.001). After the application of PEEP (6 cmH2O), FRC increased to 32.4 (5.0) ml.kg(-1) whereas the LCI decreased to 6.58 (0.5) showing no significant changes from baseline measurements. In the lateral position, neuromuscular blockade led to a significant decrease in FRC associated with a small increase in ventilation inhomogeneity. FRC and LCI were restored to baseline levels with the application of PEEP 3 cmH2O that is in addition to a background of PEEP 3 cmH2O giving a total of 6 cmH2O PEEP.Pediatric Anesthesia 09/2007; 17(9):841-5. · 2.10 Impact Factor -
Article: Decrease in functional residual capacity and ventilation homogeneity after neuromuscular blockade in anesthetized preschool children in the lateral position1
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ABSTRACT: Background: While functional residual capacity (FRC) is reduced in children undergoing general anesthesia, the lateral position leads to an increase in FRC compared with the supine position. The impact of neuromuscular blockade remains unknown. We tested the hypothesis that neuromuscular blockade leads to a decrease in FRC and increase in lung clearance index (LCI) while the application of positive endexpiratory pressure (PEEP) of 6 cmH2O leads to a restoration in both parameters.Methods: After approval of the local Ethics Committee, we studied 18 preschool children (2–6 years) without cardiopulmonary disease, who were scheduled for elective surgery. Anesthesia was standardized using propofol and fentanyl. FRC and LCI were calculated by a blinded observer using a SF6 multibreath washout technique with an ultrasonic transit-time airflow meter (Exhalyzer D). Measurements were taken in the left lateral position (PEEP 3 cmH2O) after 1. intubation with a cuffed tracheal tube, 2. neuromuscular blockade with rocuronium, and 3. the additional application of PEEP (6 cmH2O).Results: Functional residual capacity mean (sd) decreased from 31.6 (4.4) ml·kg−1 to 27.6 (4.2) ml·kg−1 (P < 0.001) following neuromuscular blockade while the LCI increased from 6.54 (0.6) to 7.0 (0.6) (P ≤ 0.001). After the application of PEEP (6 cmH2O), FRC increased to 32.4 (5.0) ml·kg−1 whereas the LCI decreased to 6.58 (0.5) showing no significant changes from baseline measurements.Conclusions: In the lateral position, neuromuscular blockade led to a significant decrease in FRC associated with a small increase in ventilation inhomogeneity. FRC and LCI were restored to baseline levels with the application of PEEP 3 cmH2O that is in addition to a background of PEEP 3 cmH2O giving a total of 6 cmH2O PEEP.Pediatric Anesthesia 08/2007; 17(9):841 - 845. · 2.10 Impact Factor -
Article: The impact of positive end-expiratory pressure on functional residual capacity and ventilation homogeneity impairment in anesthetized children exposed to high levels of inspired oxygen.
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ABSTRACT: High fractions of inspired oxygen (Fio2) result in resorption atelectasis shortly after their application. However, the impact of different levels of Fio2 and their interaction with positive end-expiratory pressure (PEEP) on functional residual capacity (FRC) and ventilation distribution is unknown in anesthetized children. We hypothesized that the use of a Fio2 of 1.0 results in a decrease of FRC and ventilation homogeneity compared with that of a Fio2 of 0.3, and that this decrease is prevented by PEEP of 6-cm H2O compared to a PEEP of 3-cm H2O. Forty-six children (3-6 yr) without cardiopulmonary disease were randomly allocated to receive PEEP of 6-cm H2O (PEEP 6 group) during the entire study period or PEEP of 3-cm H2O (PEEP 3 group). The order of the Fio2 (0.3 or 1.0) was also randomized. A defined recruitment maneuver was performed after tracheal intubation and 5 min later the first measurement. This procedure was then repeated with the second Fio2 level. FRC and lung clearance index (LCI) were calculated by a blinded observer. While FRC (mean +/- sd) was similar at both levels of Fio2 (0.3: 25.6 +/- 2.9 mL/kg vs 1.0: 25.6 +/- 2.8 mL/kg, P = 0.189) in the PEEP 6 group, FRC decreased in the PEEP 3 group (0.3: 24.9 +/- 3.8 vs 1.0: 21.7 +/- 4.1, P < 0.0001). Furthermore, with continuous PEEP of 6-cm H2O a similar LCI was observed at both levels of Fio2 (0.3: 6.45 +/- 0.4 vs 6.43 +/- 0.4, P = 0.668) while LCI increased at the higher Fio2 in the PEEP 3 group (0.3: 6.5 +/- 0.5 vs 1.0: 7.7 +/- 1.2, P < 0.0001). During the application of a very low PEEP of 3-cm H2O, FRC and ventilation distribution decreased significantly at an Fio2 of 1.0 compared with that at an Fio2 of 0.3. This decrease could be counterbalanced by the administration of PEEP of 6-cm H2O, indicating that a low level of PEEP is sufficient to maintain FRC and ventilation distribution regardless of the oxygen concentration.Anesthesia and analgesia 06/2007; 104(6):1364-8, table of contents. · 3.08 Impact Factor -
Article: Intraoperative monitoring of motor-evoked potentials in children undergoing spinal surgery.
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ABSTRACT: Clinical case series. To study the combined use of modifications of stimulation methods and adjustments of anesthetic regimens on the reliability of motor-evoked potential (MEP) monitoring in a large group of children undergoing spinal surgery. Monitoring of MEPs is advocated during spinal surgery, but systematic data from children are sparse. A total of 134 consecutive procedures in 108 children <18 years of age were analyzed. MEPs were elicited by transcranial electrical stimulation (TES) and supplemented by temporal and spatial facilitation. The standard anesthesia regimen consisted of propofol, nitrous oxide, and remifentanil. Propofol was replaced with ketamine if no reliable MEPs could be recorded. In children <6 years of age, a ketamine-based anesthesia was used. With temporal facilitation alone, reliable MEPs were obtained in 78% (105 of 134) of the procedures and, if combined with spatial facilitation, in 96% (129 of 134) of the procedures. Reliable MEPs were documented in 98% (111 of 113) of children >6 years and in 86% (18 of 21) in children <6 years of age. Combining spatial facilitation with a TES protocol improved monitoring of corticospinal motor pathways during spinal surgery in children. A ketamine-based anesthetic technique was preferred in children <6 years of age.Spine 04/2007; 32(8):911-7. · 2.08 Impact Factor -
Article: Decrease of functional residual capacity and ventilation homogeneity after neuromuscular blockade in anesthetized young infants and preschool children.
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ABSTRACT: Based on age-dependent differences in pulmonary mechanics, the effect of neuromuscular blockade may differ in infants compared with older children. The aim of this study was to determine the impact of neuromuscular blockade and its reversal by positive end-expiratory pressure (PEEP) on functional residual capacity (FRC) and ventilation distribution in young infants and preschool children. The authors studied 14 infants (aged 0-6 months) and 25 preschool children (aged 2-6 yr). FRC and lung clearance index were calculated. Measurements were taken (1) after intubation, (2) during neuromuscular blockade, and (3) during neuromuscular blockade plus application of PEEP (3 cm H2O). Functional residual capacity (mean +/- SD) decreased from 21.3 +/- 4.7 ml/kg to 12.2 +/- 4.8 ml/kg (P < 0.001) during neuromuscular blockade in infants and from 25.6 +/- 5.9 ml/kg to 23.0 +/- 5.3 ml/kg (P < 0.001) in preschool children. With the application of PEEP, FRC increased to 22.3 +/- 5.9 ml/kg (P = 0.4829, compared with baseline) in infants and 28.2 +/- 5.8 ml/kg (P < 0.001) in children. The lung clearance index increased after neuromuscular blockade, whereas baseline values were regained after the application of PEEP. The changes induced by neuromuscular blockade were significantly greater in infants compared with preschool children (P < 0.001). Although the use of neuromuscular blockade decreased FRC and ventilation distribution substantially in both groups, the changes were more pronounced in young infants. With PEEP, FRC increased and ventilation homogeneity was restored. These results provide a rationale to use PEEP in anesthetized, paralyzed infants and children.Anesthesiology 10/2006; 105(4):670-5. · 5.36 Impact Factor -
Article: Respiratory reflex responses of the larynx differ between sevoflurane and propofol in pediatric patients.
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ABSTRACT: The effects of anesthetics on airway protective reflexes have not been extensively characterized in children. The aim of this study was to compare the laryngeal reflex responses in children anesthetized with either sevoflurane or propofol under two levels of hypnosis using the Bispectral Index score (BIS). The authors hypothesized that the incidence of apnea with laryngospasm evoked by laryngeal stimulation would not differ between sevoflurane and propofol when used in equipotent doses and that laryngeal responsiveness would be diminished with increased levels of hypnosis. Seventy children, aged 2-6 yr, scheduled to undergo elective surgery were randomly allocated to undergo propofol or sevoflurane anesthesia while breathing spontaneously through a laryngeal mask airway. Anesthesia was titrated to achieve the assigned level of hypnosis (BIS 40 +/- 5 or BIS 60 +/- 5) in random order. Laryngeal and respiratory responses were elicited by spraying distilled water on the laryngeal mucosa, and a blinded reviewer assessed evoked responses. Apnea with laryngospasm occurred more often during anesthesia with sevoflurane compared with propofol independent of the level of hypnosis: episodes lasting longer than 5 s, 34% versus 19% at BIS 40 and 34% versus 16% at BIS 60; episodes lasting longer than 10 s, 26% versus 10% at BIS 40 and 26% versus 6% at BIS 60 (group differences P < 0.04 and P < 0.01, respectively). In contrast, cough and expiration reflex occurred significantly more frequently in children anesthetized with propofol. Laryngeal and respiratory reflex responses in children aged 2-6 yr were different between sevoflurane and propofol independent of the levels of hypnosis examined in this study.Anesthesiology 12/2005; 103(6):1142-8. · 5.36 Impact Factor -
Article: Improvement of motor-evoked potentials by ketamine and spatial facilitation during spinal surgery in a young child.
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ABSTRACT: Monitoring motor evoked potentials is desirable during spine surgery but may be difficult to obtain in small children. In addition, the recording of reliable signals is often hampered by the presence of various anesthetics. We report the case of a young child whose motor evoked potentials were successfully monitored using a ketamine-based anesthesia and a newly introduced stimulation technique consisting of combined spatial and temporal facilitation.Anesthesia & Analgesia 07/2005; 100(6):1634-6. · 3.29 Impact Factor -
Article: Opening the upper airway--airway maneuvers in pediatric anesthesia.
Pediatric Anesthesia 04/2005; 15(3):181-9. · 2.10 Impact Factor -
Article: The effects of common airway maneuvers on airway pressure and flow in children undergoing adenoidectomies.
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ABSTRACT: Obstruction of the upper airway occurs frequently in anesthetized, spontaneously breathing children, especially in those with adenoidal hyperplasia. To improve airway patency, maneuvers such as chin lift (CL), jaw thrust (JT), and continuous positive airway pressure (CPAP) are often used. In this study, we examined the comparative efficacy of these maneuvers in children scheduled to undergo adenoidectomy. Sixteen children aged 2-9 yr were anesthetized with sevoflurane. During spontaneous breathing, the flows and pressures in the mask (ma), oropharynx (op), and esophagus (es) were measured simultaneously, and maximal pressure differences during inspiration (DeltaP) were calculated. After baseline recording, CL and JT maneuvers were performed in random order without and with CPAP (5 cm H(2)O). The observed DeltaP(ma) - P(es) of 12.3 +/- 3.4 cm H(2)O at baseline decreased with all airway maneuvers (P < 0.05). This resulted from decreases of DeltaP(ma) - P(op) (P < 0.05) and DeltaP(op) - P(es) (P < 0.05) in all interventions except CL, in which DeltaP(ma) - P(op) remained similar. In contrast, significant improvements of minute ventilation and maximal inspiratory peak flow (P > 0.05) were observed only with JT (with and without CPAP). We conclude that CL may improve airway patency and ventilation, whereas JT with or without CPAP was the most effective maneuver to overcome airway obstruction in children with adenoidal hyperplasia. IMPLICATIONS: Airway maneuvers are often used in anesthetized children to relieve airway obstruction during spontaneous ventilation. Compared with chin lift and continuous positive airway pressure, the jaw thrust maneuver was the most effective to improve airway patency and ventilation in children undergoing adenoidectomy.Anesthesia & Analgesia 07/2003; 97(1):29-34, table of contents. · 3.29 Impact Factor -
Article: Effect of continuous positive airway pressure on the measurement of thoracoabdominal asynchrony and minute ventilation in children anesthetized with sevoflurane and nitrous oxide.
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ABSTRACT: s: To quantify thoracoabdominal asynchrony (TAA) in children during anesthesia, and to measure the effect of continuous positive airway pressure (CPAP) on TAA, tidal volume (VT), and minute ventilation (E). Prospective, nonrandomized, controlled study. Operating room of a university children's hospital. Ninety children aged 2 to 9 years scheduled for elective outpatient day surgery who were enrolled prospectively. Each subject was anesthetized with sevoflurane 3% in equal parts O2 and N2O while breathing spontaneously through a facemask. Respiratory impedance plethysmography was used to calculate TAA indexes (phase angle [PA], phase relation in inspiration [PhRIB], phase relation in expiration, phase relation in total breath [PhRTB], and ratio of the inspiratory time to the total duration of the respiratory cycle [TI/TTOT]), VT, and E. Tidal gas flows were measured with a dual-hotwire anemometer with the sensor inserted between the facemask and the Y-piece of the anesthetic breathing circuit. This enabled the volume calibration of the respiratory impedance plethysmography equipment. The following conditions were compared: (1) no CPAP, (2) CPAP of 5 cm H2O, and (3) CPAP of 10 cm H2O. Eighty-one children completed the study protocol. All measurements of TAA with an inspiratory component (PA, PhRIB, PhRTB, and TI/TTOT) decreased significantly from baseline with the addition of CPAP to the circuit. Application of CPAP of 10 cm H2O decreased significantly mean VTs and Es compared with CPAP of 5 cm H2O and no CPAP. There were no differences in TAA for all conditions when comparing children scheduled for adenoidectomy with other surgical procedures. With spontaneously breathing anesthetized children, TAA decreases with the application of CPAP. CPAP of 5 cm H2O was as effective as CPAP of 10 cm H2O in reducing PA, PhRIB, PhRTB, and TI/TTOT. However, CPAP of 10 cm H2O also caused a significant decrease in VT and E.Chest 09/2002; 122(2):473-8. · 5.25 Impact Factor
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Institutions
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2002–2010
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Universitäts-Kinderspital beider Basel (UKBB)
Basel, BS, Switzerland
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