Brazilian Journal of Anesthesiology
https://bjan-sba.org/article/doi/10.1590/S0034-70942008000500002
Brazilian Journal of Anesthesiology
Scientific Article

Influência da insuflação de gás traqueal sobre a capnografia de pacientes anestesiados

Influence of tracheal gas insufflation during capnography in anesthetized patients

Ana Carolina Ortiz; Masashi Muneshika; Fernando Antônio Nogueira da Cruz Martins

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Resumo

JUSTIFICATIVA E OBJETIVOS: A insuflação de gás traqueal (TGI - Tracheal Gas Insufflation) é uma técnica que consiste em injetar gás na traquéia (geralmente oxigênio). É usada em pacientes portadores de síndrome da angústia respiratória do adulto para reduzir a capnometria. Em Anestesiologia, a redução da capnometria pode ser útil, mas não existem estudos sobre a redução da capnometria com o uso da TGI. O presente estudo avaliou as alterações proporcionadas pela TGI sobre a capnografia em pacientes anestesiados. MÉTODO: Foram avaliados prospectivamente 11 pacientes, 18 a 60 anos, ASA I ou II, não-pneumopatas. Após a intubação traqueal foi inserido cateter para TGI a 2 ou 3 cm da carina. Os pacientes foram submetidos à ventilação controlada a volume. Registrou-se a curva de capnografia volumétrica durante 20 minutos e colheu-se amostra sangüínea para medir PaCO2. Após 20 minutos de TGI registrou-se a curva de capnografia e foi colhida nova amostra sangüínea para medir PaCO2. Avaliou-se pressão parcial de CO2 no fim da expiração (P ET CO2) e PaCO2, antes e após TGI. Observou-se curva de capnografia, antes e durante TGI. RESULTADOS: A PaCO2 e P ET CO2 sem TGI foram, respectivamente (média ± desvio-padrão): 33,48 ± 6,81 e 36,91 ± 6,54 mmHg e, após TGI, 33,85 ± 8,31 e 36,55 ± 7,93 mmHg, não havendo diferença estatística entre os valores antes e após TGI, tanto para a PaCO2 quanto para a P ET CO2 (p = 0,65 e 0,82). A curva de capnografia apresentou alterações na fase de expiração do ar alveolar. CONCLUSÕES: A aplicação da TGI não resultou em diminuição da PaCO2 e nem na P ET CO2, porém alterou a morfologia da curva de capnografia.

Palavras-chave

ANESTESIA, Geral, MONITORIZAÇÃO, CO2, VENTILAÇÃO

Abstract

BACKGROUND AND OBJECTIVES: Tracheal gas insufflation (TGI) consists in injecting gas in the trachea (usually oxygen). It is used in patients with acute respiratory distress syndrome (ARDS) to reduce capnometry. In Anesthesiology, the reduction in capnometry can be useful, but there are no studies on the reduction in capnometry using TGI. The objective of this study was to evaluate the changes caused by TGI on capnometry in anesthetized patients. METHODS: Eleven patients, ages 18 to 60 years, ASA I or II, without lung diseases were evaluated prospectively. After tracheal intubation, a TGI catheter was inserted 2 to 3 cm from the carina. Patients underwent volume-controlled ventilation. The volumetric capnography curve was recorded during 20 minutes and blood was drawn to determine the PaCO2. Twenty minutes after TGI was instituted, the capnograph curve was recorded and blood was drawn once more to measure PaCO2. The end-tidal partial pressure of CO2 (P ET CO2) and PaCO2 were evaluated before and after TGI. The capnography curve was observed before and during TGI. RESULTS: PaCO2 and P ET CO2 without TGI were: 33.48 ± 6.81 and 36.91 ± 6.54 mmHg (mean ± standard deviation), respectively, and after TGI, 33.85 ± 8.31 and 36.55 ± 7.93 mmHg, respectively. Parameters were not statistically different before and after TGI, both for PaCO2 and P ET CO2 (p = 0.65 and 0.82). The capnography curve showed changes in alveolar air during expiration. CONCLUSIONS: The use of TGI did not result in a reduction in PaCO2 or P ET CO2, but it altered the morphology of the capnography curve.

Keywords

ANESTHESIA, General, MONITORING, CO2, VENTILATION

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