Brazilian Journal of Anesthesiology
https://bjan-sba.org/article/doi/10.1590/S0034-70942008000400003
Brazilian Journal of Anesthesiology
Scientific Article

Clonidina por via venosa no pré-operatório do tratamento cirúrgico de catarata: avaliação do benefício clínico

Preoperative intravenous clonidine in the surgical treatment of cataract: evaluation of the clinical benefits

Eduardo Tocchetto Lemes; Fábio Van Der Fritz; Paulo Henrique Poti Homrich; Andressa Prestes Stolz; Julio César Mercador de Freitas; Elaine A. Felix Fortis

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Resumo

JUSTIFICATIVA E OBJETIVOS: A clonidina tem sido utilizada na anestesia por acrescentar propriedades analgésicas e sedativas, e proporcionar maior estabilidade hemodinâmica com redução da pressão intra-ocular. Este estudo avalia os efeitos clínicos da clonidina (2,5 µg.kg-1), por via venosa, na pressão intra-ocular (PIO), na hemodinâmica e na recuperação pós-anestésica do tratamento cirúrgico de catarata. MÉTODOS: Realizou-se ensaio clínico duplamente encoberto, controlado por placebo e com distribuição aleatória, que incluiu pacientes que fossem realizar operação de catarata sob bloqueio peribulbar. Após monitoração, Momento 0 (M0), eram realizadas medidas iniciais de PIO, pressão arterial média (PAM), freqüência cardíaca (FC), SpO2 e o grau de sedação (Ramsay), e então administrado placebo (Grupo P) ou clonidina (Grupo C) por via venosa. Trinta minutos após, Momento 1 (M1), eram repetidas as medidas, e novamente ao término da operação, Momento 2 (M2). RESULTADOS: Entre M0 e M1, houve diminuição diferente da PIO, 14,5% no Grupo C e 5,25% no P (p = 0,01), mantendo suas médias reduzidas até M2. A PAM do Grupo C diminuiu 17% de M0 a M1 e aumentou 3,5% no Grupo P (p < 0,001), com recuperação da PAM do Grupo C até M2 (p = 0,17). A FC diminuiu 6,4% no Grupo C e 1% no Grupo P (p = 0,1) de M0 a M1. Houve aumento da sedação no Grupo C em relação ao P (p < 0,001), porém sem ocorrência de depressão respiratória. O RR de hipertensão arterial no intra-operatório do Grupo C foi 0,657 (IC95% 0,517 a 0,835), p < 0,01. Não houve diferenças em relação à incidência de taquicardia, hipoxemia, hipotensão arterial, nem retardo da alta hospitalar. CONCLUSÕES: A clonidina, nas condições deste estudo, foi um fármaco seguro e diminuiu a PIO e o risco de hipertensão arterial intra-operatória sem retardar a alta hospitalar.

Palavras-chave

ANALGÉSICOS, CIRURGIA, Oftalmológica, CIRURGIA, Oftalmológica, CIRURGIA, Oftalmológica, CIRURGIA, Oftalmológica, SEDAÇÃO

Abstract

BACKGROUND AND OBJECTIVES: Clonidine has been used in anesthesia for its sedative and analgesic properties, and to achieve greater hemodynamic stability with reduction in intra-ocular pressure. This study evaluated the clinical effects of intravenous clonidine (2.5 µg.kg-1) on the intra-ocular pressure (IOP), hemodynamic parameters, and post-anesthetic recovery in the surgical treatment of cataract. METHODS: This is a randomized, double-blind, placebo-controlled study that included patients undergoing cataract surgery under peribulbar block. After placement of monitoring devices, baseline (M0) values of IOP, mean arterial pressure (MAP), heart rate (HR), SpO2, and the degree of sedation (Ramsay) were determined. Afterwards, placebo (Group P) or clonidine (Group C) was administered intravenously. After 30 minutes, at Moment 1 (M1), measurements were repeated, and once again at the end of the surgery, at Moment 2 (M2). RESULTS: The change in IOP between M0 and M1 was different for both groups, 14.5% in Group C and 5.25% in Group P (p = 0.01), and the means remained reduced until M2. Mean arterial pressure in Group C showed a 17% reduction from M0 to M1 and increased 3.5% in Group P (p < 0.001) and in Group C it showed a recovery at M2 (p = 0.17). The heart rate decreased 6.4% in Group C and 1% in Group P (p = 0.1) from M0 to M1. There was a greater sedation in Group C when compared with Group P (p < 0.001) but there was no cases of respiratory depression. The relative risk of intraoperative hypertension was 0.657 (CI 95% 0.517 to 0.835) in Group C, p < 0.01. Differences in the incidence of tachycardia, hypoxemia, hypotension, and increased hospital staying were not observed between both groups. CONCLUSIONS: Clonidine, under the conditions of the present study, showed to be a safe drug and decreased IOP and the intraoperative risk of hypertension without delaying hospital discharge.

Keywords

ANALGESICS, SEDATION, SURGERY, Ophthalmologic, SURGERY, Ophthalmologic, SURGERY, Ophthalmologic, SURGERY, Ophthalmologic

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