Comparação da acurácia diagnóstica da variação da pressão de pulso obtida em artéria periférica ou em artéria central na predição da fluido-responsividade em cães
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Data
2021-03-01
Autores
Lobo, César Passareli Candido
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Objetivos: Objetivou-se comparar a predição da fluido-responsividade com a variação da pressão de pulso (VPP) mensurada em artéria periférica (VPPperiférica) em relação a VPP mensurada em artéria central (VPPcentral). Como objetivo secundário, avaliou-se o impacto da administração de uma prova de carga com cristaloide na função diastólica do ventrículo esquerdo (VE). Material e Métodos: Em um estudo experimental prospectivo, 30 cães hígidos (22 ± 4,3 kg) submetidos a cirurgia eletiva foram submetidos a anestesia geral com isoflurano sob ventilação controlada a volume (volume corrente = 12 mL/kg; relação inspiração/expiração = 1:2; pausa inspiratória de 30% do tempo inspiratório). O débito cardíaco / volume sistólico (VS) foi mensurado através da técnica de termodiluição transpulmonar e a VPP foi obtida através de cateteres inseridos na artéria aorta abdominal (VPPcentral) e artéria dorsal podal (VPPperiférica). Antes do procedimento cirúrgico, a fluido-responsividade foi avaliada através de uma ou mais provas de carga, empregando-se 10 mL/kg de solução de Ringer Lactato administrado durante 5 minutos. Elevações no VS ≥15% em resposta a prova de carga definiram os animais respondedores à expansão volêmica. Para se obter a mesma proporção de respondedores e não respondedores (n = 15 por grupo), provas de carga adicionais (10 mL/kg de Ringer lactato durante 5 minutos) foram administradas nos animais alocados ao grupo de não respondedores, caso a elevação do VS após primeira prova de carga fosse ≥15, até que a elevação do VS fosse <15%. As variáveis hemodinâmicas e parâmetros ecocardiográficos de função diastólica, foram registrados imediatamente antes e após a última prova de carga que caracterizou o status de fluido-responsividade. Resultados: A área sob a curva receiver operating characteristics (intervalos de confiança de 95%) da VPPcentral [0.956 (0.871–1.0)] não diferiu da VPPperiférica [0.991 (0,971–1.0)] (p = 0.30) (p = 0,3). Os valores de corte para predição de respondedores e a zona de incerteza diagnóstica (gray zone) foram >16% (14–18%) e >16% (14– 17%) para a VPPcentral e VPPperiférica, respectivamente. A porcentagem de animais localizados dentro da gray zone foi maior para a VPPcentral (27%) do que para a VPPperiférica (17%). A ecocardiografia de um animal do grupo de não respondedores foi excluída da análise porque não foi possível obter alinhamento adequado do Doppler pulsado com o fluxo transmitral. A velocidade máxima do fluxo transmitral no início da diástole (onda E) foi <120 cm/seg e a relação entre a onda E / velocidade máxima do anel mitral no início da diástole (razão E/E') foi ≤12 em todos os animais de ambos os grupos. Conclusões: A VPP, independentemente do local de mensuração (artéria central ou periférica), é capaz de predizer de forma satisfatória o status de fluido-responsividade em cães. Entretanto, a VPPperiférica apresentou acurácia diagnóstica discretamente superior (gray zone mais estreita e contendo menor percentagem de indivíduos) que a VPPcentral. A maximização do VS através da administração repetida de provas de carga (grupo de não respondedores), não resultou em evidências ecocardiográficas de aumentos excessivos da pressão de enchimento do VE na população estudada.
Objectives: This study aimed to compare prediction of fluid responsiveness by pulse pressure variation (PPV), measured from a central and a peripheral artery, and to evaluate the effects of a fluid challenge (FC) on left ventricular diastolic function in anesthetized normovolemic dogs. Material and Methods: In a prospective, experimental study, thirty adult healthy dogs (2 ± 4,3 kg) scheduled for elective surgery were anesthetized with isoflurane under volume-controlled ventilation (tidal volume: 12 mL/kg; inspiratory pause: 30% of inspiratory time). Cardiac output/stroke volume (SV) were measured by transpulmonary thermodilution. Increases in SV ≥15% induced by a fluid challenge with lactated Ringer´s solution (10 mL/kg over 5 minutes) defined responders to volume expansion. Additional fluid challenges were administered as necessary in 50% of dogs until animals became nonresponders (SV <15%). Fluid responsiveness status was based on the response to the last fluid challenge. The PPV was simultaneously recorded from a dorsal pedal artery catheter (PPVperipheral) and from a femoral catheter advanced into the abdominal aorta (PPVcentral). Changes in LVDF were evaluated by transthoracic Doppler echocardiography. Results: The area under the receiver operating characteristics curve (95% confidence intervals) of PPVcentral [0.956 (0.871–1.0)] and PPVperipheral [0.991 (0,971–1.0)] did not differ (p = 0.30). The best cut-off value for identifying responders and zone of diagnostic uncertainty (gray zone) were >16% (14–18%) and >16% (14–17%) for PPVcentral and PPVperipheral, respectively. Percentage of animals within the gray zone was 27% (PPVcentral) and 17% (PPVperipheral). Echocardiography of one animal from the group of nonresponders was excluded from analysis because proper alignment of Doppler beam with the transmitral flow could not be obtained. Early diastolic transmitral flow velocity (E wave) was <120 cm/sec and the ratio between the E wave and early diastolic mitral annular tissue velocity (E/E' ratio) was ≤12 in all animals. Conclusions: Pulse pressure variation, regardless of the site of measurement (central or peripheral artery), can satisfactorily predict fluid responsiveness in dogs. However, accuracy of PPVperipheral was slightly superior (narrower gray zone containing fewer individuals form the population) than PPVcentral. Stroke volume maximization via repeated fluid challenge administration (group of nonresponders) did not result in echocardiographic signs of excessively increased left ventricular filling pressure in this population of dogs.
Objectives: This study aimed to compare prediction of fluid responsiveness by pulse pressure variation (PPV), measured from a central and a peripheral artery, and to evaluate the effects of a fluid challenge (FC) on left ventricular diastolic function in anesthetized normovolemic dogs. Material and Methods: In a prospective, experimental study, thirty adult healthy dogs (2 ± 4,3 kg) scheduled for elective surgery were anesthetized with isoflurane under volume-controlled ventilation (tidal volume: 12 mL/kg; inspiratory pause: 30% of inspiratory time). Cardiac output/stroke volume (SV) were measured by transpulmonary thermodilution. Increases in SV ≥15% induced by a fluid challenge with lactated Ringer´s solution (10 mL/kg over 5 minutes) defined responders to volume expansion. Additional fluid challenges were administered as necessary in 50% of dogs until animals became nonresponders (SV <15%). Fluid responsiveness status was based on the response to the last fluid challenge. The PPV was simultaneously recorded from a dorsal pedal artery catheter (PPVperipheral) and from a femoral catheter advanced into the abdominal aorta (PPVcentral). Changes in LVDF were evaluated by transthoracic Doppler echocardiography. Results: The area under the receiver operating characteristics curve (95% confidence intervals) of PPVcentral [0.956 (0.871–1.0)] and PPVperipheral [0.991 (0,971–1.0)] did not differ (p = 0.30). The best cut-off value for identifying responders and zone of diagnostic uncertainty (gray zone) were >16% (14–18%) and >16% (14–17%) for PPVcentral and PPVperipheral, respectively. Percentage of animals within the gray zone was 27% (PPVcentral) and 17% (PPVperipheral). Echocardiography of one animal from the group of nonresponders was excluded from analysis because proper alignment of Doppler beam with the transmitral flow could not be obtained. Early diastolic transmitral flow velocity (E wave) was <120 cm/sec and the ratio between the E wave and early diastolic mitral annular tissue velocity (E/E' ratio) was ≤12 in all animals. Conclusions: Pulse pressure variation, regardless of the site of measurement (central or peripheral artery), can satisfactorily predict fluid responsiveness in dogs. However, accuracy of PPVperipheral was slightly superior (narrower gray zone containing fewer individuals form the population) than PPVcentral. Stroke volume maximization via repeated fluid challenge administration (group of nonresponders) did not result in echocardiographic signs of excessively increased left ventricular filling pressure in this population of dogs.
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Palavras-chave
Função diastólica, Prova de carga, Fluido-responsividade, Variação da pressão de pulso, Diastolic function, Fluid challenge, Fluid responsiveness, Pulse pressure variation