ECMO is an extracorporeal life support technology which can effectively replace heart and lung function. ECMO can provide cardiopulmonary support to patients with severe heart and lung failure, thereby valuable time for recovery of cardiopulmonary function can be obtained.8,9 There are usually two types of neonatal ECMO patterns, venoarterial (VA) and venovenous (VV) ECMO. VA ECMO is established by cannulation of the right internal jugular vein and carotid artery, and VV ECMO is established by dual lumen cannulation of the right internal jugular vein. Neonate with severe respiratory failure often have severe hypoxemia, acidosis, and pulmonary hypertension, all of them can lead to heart failure. VA ECMO can provide both respiratory and cardiac support, but VV ECMO can not provide cardiac support. In addition, for neonates, the internal jugular vein small, and it is difficult to insert the dual lumen cannulation. Therefore, the VA ECMO was the selected method for most neonates.10,11 VA ECMO was adopted in all neonates in our center.
Successful cannulation is a necessary condition for the establishment of ECMO, and rapid establishment of a suitable circulation access in a short time is the key to implement ECMO.12 At the same time, studies have found that the longer the cannulation time, the higher the risk of infection.13 Neonatal blood vessel wall is thin, tissue is fragile, and neck incision operation space is limited. In order to complete ECMO cannulation quickly and successfully, the operator must be familiar with the anatomical structure of neck vessels and have experience in cardiac surgery. The operator in our center were cardiac surgeons with 10 years of experience in cardiac surgery, and the operation time of cannulation was 29 (22–40) minutes.
Stable flow rate is very important to the work of ECMO, and good position of cannulation is the premise of stable flow of ECMO.14,15 If the position of cannulation is improper, and too deep or too shallow is prone to frequent problems of poor drainage, it is easy to result in unstable ECMO flow. Once ECMO is stopped, the patient’s life is at risk. Frequent adjusting of ECMO cannulation would cause vascular damage and increase the risk of infection. The ECMO venous cannula has a 3cm lateral hole. Our experience has shown that the ideal location for venous cannulation was the position of inferior vena cava entering the right atrium. This location can allow most of the lateral holes of the venous cannulation to be located in the right atrium, which can provide stable flow. The venous cannulation of all patients in our center were intubated in the position of inferior vena cava entering the right atrium, and the flow of all patients was stable during ECMO. No patients need adjust the position of venous cannulation. The ideal location of arterial cannulation is the innominate artery entering the aortic arch, where would not increase left ventricular afterload. However, due to the short path, the intubation only need about 3cm, so the cannulation was easy to take off. Stable fixation was very important, and we attach one more fixed cannula to the artery than the vein. In order to ensure the accuracy of the cannulation position, cardiac ultrasound detection was applied after intubation and cannulation position was instructed to adjust via cardiac ultrasound. When the cannulation reached the correct location, we firmly fixed cannulation of the internal jugular vein and carotid and the closed incisions. Then a bedside chest radiograph was taken to reconfirm the cannulation location. Through these methods, the ECMO flow of all patients was stable, and no patients need adjust the position of cannulation and no complications of cannulation accidentally pulling away occurred.
Intraoperative and postoperative complications of ECMO intubation should not be ignored. 16 Incisional bleeding, vascular laceration and incisional infection were common complications. It was important to be careful and use blunt separation method to dissociate the tissue during the operation. It would not only reduce the amount of bleeding, but also provide a clear position of blood vessels in the neck. When dissociating blood vessels we should gently operate to avoid damaging the vessel wall and causing bleeding. We should also avoid excessively pulling the blood vessels, otherwise it would result in venous contracture which would increase the difficulty of intubation. When intubating, we should pay attention to the angle and force of the tube, and we should not intubate violently. After the cannulation entered the purse incision, the cannulation should be inserted with rotating moving. At the same time, the proximal cannulation should be gently lifted to make the angle of inserting cannulation consistent with the vessel as far as possible. After successful intubation, ligating the distal end of the artery and vein, tightening of the proximal end of the purse and fixing with cannula can effectively reduce the vascular bleeding at the intubation site. Intubation of ECMO was often performed at the bedside, where would increases the risk of infection.17,18 De Rita et al. found that infection of intubation site occurred in 15% of cases.19 Only one case of poor neck incision healing occurred in our center, and no incision infection or catheter-related blood infection occurred. The main reason was that the operation was performed in a intensive care unite with laminar flow equipment, and we strictly followed aseptic surgical operations. Study have shown that catheter-related blood infection rate can be 0% under standard intubation procedures.20
DPolito A et al. found that the neurological complications of children with VA ECMO were higher than those with VV ECMO, and they considered the reason was that the carotid artery been ligature.21 Neonatal carotid arteries and jugular veins were thin and vascular walls was thin, which was difficult to anastomosis, and there was still the risk of obstruction or even occlusion after reanastomosis. In order to improve the success rate of internal jugular vein and carotid artery anastomosis. The experience of our center was to place a hose pad between the ligation line and the vessel, when fixing the proximal end of the cannulation and ligaturing distal end of jugular vein and carotid artery. In this way, it was not only easier to remove the ligation line, but also did not damage the blood vessels. We removed the purse line of 5 − 0 prolene, then we used 8 − 0 prolene line to anastomose jugular vein and carotid artery. The non-invasive forceps was used to protect vascular during the anastomosing. In our study, 8 patients were successfully reconstructed the internal jugular vein and carotid artery. Arterial blood flow was unobstructed in 5 patients, mild stenosis in 2 patient, moderate stenosis in 1 patient. Venous blood flow was unobstructed in 6 patients, mild stenosis in 1 patient, and moderate stenosis in 1 patient.
This study had some limitations. First, this study was a retrospective study. Second, this study was a single-center study with a small sample size.