Comparison of sevoflurane concentration for insertion of proseal laryngeal mask airway and tracheal intubation in children (correlation with BIS) / Comparação da concentração de sevoflurano para a inserção de ML proseal e intubação traqueal em crianças (correlação com BIS)

BACKGROUND: Sevoflurane is an inhalational agent of choice in paediatric anaesthesia. For management of airways in children a suitable alternative to ETT is a paediatric proseal laryngeal mask airway (benchmark second generation SAD). Various studies have shown that less sevoflurane concentration is required for LMA insertion in comparison to TI. BIS is a useful monitor of depth of anaesthesia. AIMS: To compare concentration of sevoflurane (end tidal and MAC value) required for proseal laryngeal mask airway insertion and tracheal intubation in correlation with BIS index. METHOD: The prospective randomised single blind study was done in children between 2 and 9 years of ASA I and II and they were randomly allocated to Group P (proseal laryngeal mask airway insertion) and Group TI (tracheal intubation). No sedative premedication was given. Induction was done with 8% sevoflurane and then predetermined concentration was maintained for 10 min. Airway was secured either by proseal laryngeal mask airway or endotracheal tube without using muscle relaxant. End tidal sevoflurane concentration, MAC, BIS, and other vital parameters were monitored every minute till insertion of an airway device. Insertion conditions were observed. Statistical analysis was done by ANOVA and Students t test. RESULTS: Difference between ETLMI (2.49 ± 0.44) and ETTI (2.81 ± 0.65) as well as MACLMI (1.67 ± 0.13) and MACTI (1.77 ± 0.43) was statistically very significant, while BISLMI (49.05 ± 10.76) and BISTI (41.25 ± 3.25) was significant. Insertion conditions were comparable in both the groups. CONCLUSION: We can conclude that in children airway can be secured safely with proseal laryngeal mask airway using less sevoflurane concentration in comparison to tracheal intubation and this was supported by BIS index.

JUSTIFICATIVA: Sevoflurano é um agente inalatório de escolha em anestesia pediátrica. Para o manejo de vias aéreas em crianças, uma opção adequada para o TET é uma MLP pediátrica (referência de segunda geração SAD). Vários estudos mostraram que uma menor concentração do sevoflurano é necessária para a inserção da ML em comparação com a IT. O BIS é um monitor útil da profundidade da anestesia. OBJETIVOS: Comparar a concentração de sevoflurano (valores no fim da expiração e da CAM) necessária para a inserção de MLP e intubação traqueal em correlação com o BIS. MÉTODO: Estudo prospectivo, randômico e cego conduzido com crianças entre 2-9 anos, estado físico ASA I-II, randomicamente alocados nos grupos P (inserção de MLP) e IT (intubação traqueal). Pré-medicação sedativa não foi administrada. A indução foi feita com sevoflurano a 8% e, em seguida, a concentração predeterminada foi mantida durante 10 minutos. A via aérea foi garantida por MLP ou tubo endotraqueal, sem o uso de relaxante muscular. A concentração de sevoflurano no fim da expiração, CAM, BIS e outros parâmetros vitais foram monitorados a cada minuto até a inserção do dispositivo respiratório. As condições de inserção foram observadas. A análise estatística foi feita com o teste t de Student e Anova. RESULTADOS: As diferenças entre TEIML (2,49 ± 0,44) e TEIT (2,81 ± 0,65), bem como CAMIML (1,67 ± 0,13) e CAMIT (1,77 ± 0,43), foram estatisticamente muito significativas; enquanto BISIML (49,05 ± 10,76) e BISIT (41,25 ± 3,25) foram significativos. As condições de inserção foram comparáveis em ambos os grupos. CONCLUSÃO: Podermos concluir que a MLP em comparação com a intubação traqueal pode ser segura para a via aérea de crianças com o uso de menos concentração de sevoflurano, o que foi confirmado pelo BIS.

Correlation of cardiac output and sevoflurane required to maintain anesthetic depth targeted with entropy index.

Aims and Objectives: We investigated the correlation of reduced cardiac output on required sevoflurane to maintain targeted anesthesia depth. Materials and Methods: 36 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively included in the study. Inspired sevoflurane concentration was adjusted to ensure state entropy index < 40. Analgesia was provided by either boluses of fentanyl 200 μg or continuous infusion of fentanyl 5 μg/kg/h; the total dose of fentanyl administered in the patients was not different (fentanyl boluses 6.5 ± 0.3 μg/kg/h vs. fentanyl infusion 5 μg/kg/h). Cardiac‑index (CI), end tidal sevoflurane (ETsev) and entropy index were measured simultaneously at 1‑5 min after sternotomy, during internal mammary artery harvesting and during pericardiotomy. 108 sets of variables (entropy index, ETsev, CI) were recorded from 36 subjects at three time points; 13 sets were excluded due to technical drawbacks in measurements. 95 data sets were eligible for analysis. Sixty-five data sets measured in patients with target state entropy index were analyzed to establish the relationship between CI and ETsev. Results: We did not find a linear correlation between ETsev and CI in patients with target entropy index (correlation coefficient = 0.18, P = 0.14). The ЕТsev necessary to maintain the target level of anesthesia was lower in patients with CI ≤ 2.2 l/min/m2 (1.15% ± 0.28%) than patients with CI > 2.2 l/min/m2 (1.37% ± 0.31%), P = 0.01. Conclusion: Relationship between CI and ETsev required for maintaining target level of anesthesia is non‑linear. Patients with CI ≤ 2.2 l/min/m2 need lower levels of the ETsev for maintenance of the target anesthesia at an entropy index < 40.

Sevoflurane for central venous catheterization in non-intubated neonates.

OBJECTIVE: Sedation in neonates undergoing invasive prodedures as central venous catheterization (CVC) remains contro versial. Sevoflurane is an inhaled anesthetic whose periods of action and elimination are very short. The objective of this study was to evaluate the use of sevoflurane for sedation for central venous catheterization (CVC) in non-intubated neonates and preterms. METHODS: Thirty three (33) consecutive patients (range: 1-31 days old, 26 to 40 weeks GA, weighing 580 to 3200 g) were included over a 4 months period. Sevoflurane was progressively increased, until loss of consciousness and motor response to stimulation. FiO(2), heart rate (HR), mean arterial pressure (MAP), duration of the procedure and the ease of the procedure were recorded. RESULTS: HR was very stable, but MAP dropped significantly. No patient required intubation. The ease of the procedure was scored as average 13 times and excellent 20 times. CONCLUSION: The use of sevoflurane in neonates for CVC is feasible and achieve the goals of procedural sedation. The pharmacokinetic of sevoflurane enabled rapid adjustment of the depth of sedation. Sevoflurane appears to be a new agent at the disposal of neonatologists. Its use does not come without risks, especially for smaller preterms, which the treating clinician must anticipate.

Sevofluorano: un paso más en la búsqueda del anestésico inhalatorio ideal / Sevofluorane: another stage in the search of the ideal inhalatory anesthetic

El sevofluorano, un isopropil metil eter fluorinado, es un potente anestésico inhalatorio halogenado de amplio uso actualmente en Japón. Sus partículas características farmacocinéticas farmacodinámicas lo aproximan al anestésico inhalatorio ideal y lo hacen apto para la mayoría de las situaciones quirúrgicas, incluso muchas que hoy se presentan como un desafío para los anestesiólogos en su práctica diaria. Su pronta incorporación al arsenal anestesiológico obliga al profesional a un acabado conocimiento del mismo