Three dogs (mean weight, 29.3±3.4 kg) underwent video-assisted tracheal reconstruction using veno-RV ECMO. Moderate hypothermic (33°C) veno-RV ECMO was maintained at 100 mL/kg/min for 30 min without lung mechanical ventilation during tracheal reconstruction. Hemodynamic stability and satisfactory oxygenation of the FA was achieved during this procedure (Table 2). Despite video-assisted thoracic surgery, tracheal reconstruction without direct intraoperative endobronchial tube ventilation could be performed with satisfactory visualization (Fig 5). Heparinization caused no bleeding problems, and no complications resulted from this incidental use of extracorporeal circulation. On completion of this procedure, the animals were weaned easily from veno-RV ECMO without inotropic support and they were all hemodynamically stable. The tracheal tube was removed 6 h after the operation. No dog died of hypoxia after being taken off the bypass and the postoperative recovery was uneventful. Sixty weeks after the operation, all three dogs were examined using fiber bronchoscopy, which revealed no evidence of stenosis at the anastomosis sites (Fig 6). canadian neighbor pharmacy
ECMO has been used with simple veno-venous access using two catheters or a double-lumen catheter. However, if ECMO is used with veno-venous access and with no contribution from the lungs supplied by mechanical ventilation, ECMO could not achieve satisfactory oxygenation and provide total lung support. This is because it is impossible to achieve a bypass flow nearly equal to the cardiac output with ECMO using the veno-venous cannula-tion technique without significant recirculation of oxygenated blood.
This problem is described in the article by Wetterberg and Steen. In an attempt to overcome it, Koul et al carried out ECMO using veno-right ventricle cannulation access with the aim of minimizing the possible recirculation of the oxygenated blood in the extracorporeal circuit; they demonstrated that veno-RV ECMO could provide effective total lung support. Although Koul et al showed that veno-RV ECMO was effective, they applied dead space ventilation (volume-controlled ventilation, 1 L/min; frequency, 20/min; positive end-expiratory pressure, 5 cm HaO; fraction of inspired oxygen, 0.21) during veno-RV ECMO. The efficacy of veno-RV ECMO without mechanical ventilation under conditions of complete lung collapse were unknown.
Table 2—Hemodynamic and Arterial Blood Gas Values Before Veno-RV ECMO, During Veno-RV ECMO, and After Restarting Ventilation in Survival Experimental Model (n=3)
|Before \eno-KYKCMO||10 min After Starting Veno-RV ECMO||After Restarting Ventilation|
|60 mill||ISO min||300 min|
|11R, beats/min||176±5.9||1 SO ± 14.9||IS7± 12.1||178 ±17.8||163 ±15.1|
|FP, mm Hg||128±16.l||132±16.2||108+14.4||110± 1.3.4||103±13.1|
|Hemoglobin, g/dL||15.4±2.1||13.8±3.1||15.1 ±3.4||15.1 ±3.2||14.4±2.7|
|pH||7.39±0.03||7.35±0.32||7.41 ±0.08||7.43±0.05||7.41 ±0.08|
|PaC()2, nnn Hi;||29.9±3.73||22.0 ±7.89||31.6±7.35||36.3±3.91||33.3±3.30|
|Sf’aO,. %||98.9± 1.10||99.5±0.78||99.9 ±0.05||99.9±4.06||99.8±0.72|
|IICO3 . niKq/L||17.8 ±1.34||12.5±4.92||19.8±5.03||22.5±3.03||20.9±3.23|
|BE, mKq/I.||-5.1 ±1.04||— I2.4±3.S0||—3.4±5.06||-2.1 ±2074||—2.3±3.76|
Figure 5. Thoraeoscopic view of the tracheal anastomosis. SVC=superior vena cava.
Figure 6. Fiber bronehoscopie findings 60 weeks after videoassisted traeheal reconstruction. There is no stenosis at the anastomotic site.