Abordagem da valva do tronco pulmonar por desvio direito e uso de cânula bicaval: estudo experimental / Approach of the pulmonary valve using right heart bypass and bicaval cannula: experimental study

OBJETIVO: O objetivo deste estudo foi reproduzir a cirurgia de abordagem da valva do tronco pulmonar por desvio direito, avaliando-se uma nova cânula venosa bicaval com balonetes insufláveis para uso por miniacesso. MÉTODOS: Utilizaram-se 15 suínos da raça Large-White, sendo cinco para a padronização técnica das vias de acesso e monitorização hemodinâmica, nove submetidos ao experimento por meio de esternotomia, e um animal excluído da amostra, operado por mínimo acesso ao tórax. O desvio direito foi estabelecido pela drenagem bicaval, sendo a cânula introduzida pela veia jugular interna direita e locada nas veias cavas cranial e caudal. Os parâmetros medidos foram: Pressão Arterial Média (PAM); Freqüência Cardíaca (FC); Saturação O2 (SAT O2); Capnografia (PetCO2) e Temperatura (T). A análise estatística foi feita comparando-se os valores antes e durante o desvio direito. RESULTADOS: No momento pré-desvio direito, obtiveramse os seguintes valores médios: PAM = 90,8 mmHg, FC = 101,6 bat/min, SAT O2 = 93,8 por cento, PetCO2 = 28,4 mmHg, T = 36,1ºC. Durante o desvio direito, obtiveram-se os seguintes valores médios: PAM = 88,1 mmHg, FC = 98,0 bat/min, SAT O2 = 93,1 por cento, PetCO2 = 25,3 mmHg e T = 36,9ºC. Comparandose as médias obtidas entre os dois momentos, verificou-se não haver diferenças significantes para a PAM, FC e SAT O2 e diferenças significantes para a PetCO2 e a T. CONCLUSÃO: A cânula bicaval com balonetes promoveu drenagem eficaz de ambas as veias cavas, permitindo a manutenção dos parâmetros hemodinâmicos durante o desvio direito, sendo possível realizar a abordagem da valva pulmonar.

OBJECTIVE: To reproduce the surgery for correction of pulmonary valve anomalies using right heart bypass and a new bicaval cuffed venous cannula for minimal access surgery. METHODS: Fifteen Large-White pigs were used for this study. The standard technique model was established with the first five pigs, the experiment was done with nine animals by sternotomy, and one was submitted to a minimally invasive procedure, but has been excluded of the sample. Bicaval drainage by a single cannula was obtained through the internal jugular vein. The cuffs were inflated to increase blood flow to the machine. The return was established by putting the arterial cannula into the pulmonary artery trunk. Pre-bypass parameters were measured and compared with the parameters during the right bypass: Median Arterial Tension (MAT); Heart Rate (HR); O2 Saturation (SAT O2); end-tidal CO2 measures (etCO2); Temperature (T). The statistical analysis was done comparing the pre-bypass and during bypass values. RESULTS: Pre-bypass values: MAT: 90.8 mmHg; HR = 101.6 beat/min; O2 SAT = 93.8 percent; PetCO2 = 28.4 mmHg; T = 36.1ºC. During bypass the obtained values were: MAT: 88.1 mmHg; HR = 98.0 beat/min; O2 SAT = 93.1 percent; PetCO2 = 25.3 mmHg; T = 36.9ºC. Comparing the average values between the two abovementioned moments, no significant difference occurred in MAT, HR and O2 SAT; PetCO2 and T presented significant differences. CONCLUSIONS: The bicaval cuffed venous cannula showed efficient drainage of both venae cavae with appropriate hemodynamic parameters during right bypass allowing access to the pulmonary valve.

Approach of the pulmonary valve using right heart bypass and bicaval cannula: experimental study.

OBJECTIVE: To reproduce the surgery for correction of pulmonary valve anomalies using right heart bypass and a new bicaval cuffed venous cannula for minimal access surgery. METHODS: Fifteen Large-White pigs were used for this study. The standard technique model was established with the first five pigs, the experiment was done with nine animals by sternotomy, and one was submitted to a minimally invasive procedure, but has been excluded of the sample. Bicaval drainage by a single cannula was obtained through the internal jugular vein. The cuffs were inflated to increase blood flow to the machine. The return was established by putting the arterial cannula into the pulmonary artery trunk. Pre-bypass parameters were measured and compared with the parameters during the right bypass: Median Arterial Tension (MAT); Heart Rate (HR); O2 Saturation (SAT O2); end-tidal CO2 measures (etCO2); Temperature (T). The statistical analysis was done comparing the pre-bypass and during bypass values. RESULTS: Pre-bypass values: MAT: 90.8 mmHg; HR = 101.6 beat/min; O2 SAT = 93.8%; PetCO2 = 28.4 mmHg; T = 36.1 degrees C. During bypass the obtained values were: MAT: 88.1 mmHg; HR = 98.0 beat/min; O2 SAT = 93.1%; PetCO2 = 25.3 mmHg; T = 36.9 degrees C. Comparing the average values between the two abovementioned moments, no significant difference occurred in MAT, HR and O2 SAT; PetCO2 and T presented significant differences. CONCLUSIONS: The bicaval cuffed venous cannula showed efficient drainage of both venae cavae with appropriate hemodynamic parameters during right bypass allowing access to the pulmonary valve.