RESUMO
BACKGROUND: The aim of this study was to determine whether, after propofol, rocuronium and remifentanil rapid sequence induction, inhaled anaesthetic agents should be started before intubation to minimize autonomic and arousal response during intubation. METHODS: One hundred ASA I and II patients were randomized to receive 1 MAC of desflurane or sevoflurane during manual ventilation or not. Anaesthesia was induced with an effect-site-controlled infusion of remifentanil at 2 ng ml(-1) for 3 min. Patients then received propofol to induce loss of consciousness (LOC). Rocuronium (0.6 mg kg(-1)) was given at LOC and the trachea was intubated after 90 s of manual breathing support (=baseline) with or without inhaled anaesthetics. Vital signs and bispectral index (BIS) were recorded until 10 min post-intubation to detect autonomic and arousal response. RESULTS: A significant increase in BIS value after intubation was seen in all groups. The increases were mild, even in those not receiving pre-intubation inhaled anaesthetics. However, in contrast to sevoflurane, desflurane appeared to partially blunt the arousal response. Heart rate, systolic and diastolic pressure increase similarly in all groups. CONCLUSIONS: Desflurane and sevoflurane were unable to blunt the arousal reflex completely, as measured by BIS, although the reflex was significantly less when desflurane was used. Rapid sequence induction with remifentanil, propofol and rocuronium and without inhaled anaesthetics before intubation can be done without dangerous haemodynamic and arousal responses at intubation after 90 s.
Assuntos
Anestésicos Inalatórios , Anestésicos Intravenosos , Nível de Alerta/efeitos dos fármacos , Intubação Intratraqueal/métodos , Adulto , Androstanóis , Anestésicos Combinados , Pressão Sanguínea/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Humanos , Laringoscopia , Pessoa de Meia-Idade , Piperidinas , Propofol , Remifentanil , RocurônioRESUMO
Carbon monoxide can be formed when volatile anaesthetic agents such as desflurane and sevoflurane are used with anaesthetic breathing systems containing carbon dioxide absorbents. This review describes the possible chemical processes involved and summarises the experimental and clinical evidence for the generation of carbon monoxide. We emphasise the different conditions that were used in the experimental work, and explain some of the features of the clinical reports. Finally, we provide guidelines for the prevention and detection of this complication.
Assuntos
Anestésicos Inalatórios/química , Monóxido de Carbono/química , Absorção , Adolescente , Anestesia com Circuito Fechado , Animais , Compostos de Cálcio/química , Pré-Escolar , Desflurano , Feminino , Depuradores de Gases , Humanos , Isoflurano/análogos & derivados , Isoflurano/química , Masculino , Éteres Metílicos/química , Pessoa de Meia-Idade , Óxidos/química , Sevoflurano , Hidróxido de Sódio/química , SuínosRESUMO
Two new generation carbon dioxide absorbents, DrägerSorb Free and Amsorb Plus, were studied in vitro for formation of compound A or carbon monoxide, during minimal gas flow (500 ml x min(-1)) with sevoflurane or desflurane. Compound A was assessed by gas chromatography/mass spectrometry and carbon monoxide with continuous infrared spectrometry. Fresh and dehydrated absorbents were studied. Mean (SD) time till exhaustion (inspiratory carbon dioxide concentration >or= 1 kPa) with fresh absorbents was longer with DrägerSorb Free (1233 (55) min) than with Amsorb Plus (1025 (55) min; p < 0.01). For both absorbents, values of compound A were < 1 ppm and therefore below clinically significant levels, but were up to 0.25 ppm higher with DrägerSorb Free than with Amsorb Plus. Using dehydrated absorbents, values of compound A were about 50% lower than with fresh absorbents and were identical for DrägerSorb Free and Amsorb Plus. With dehydrated absorbents, no detectable carbon monoxide was found with desflurane.
