Non-intubated VATS with epidural anesthesia for metastatic lung tumor was first performed by Vincenzo et al. in 2001, with achievement of satisfactory short- and long-term results . Non-intubated VATS is used for patients with low respiratory function due to conditions such as large unilateral pleural effusion, emphysema, diffuse lung disease, multiple nodules, pericardial effusion with coexisting pleural effusion, and chronic hemothorax . The surgical procedures include partial pneumonectomy and lobectomy for pneumothorax and lung tumor, and lung volume reduction surgery for emphysema .
The advantages of spontaneous breathing without intubation include prevention of tears caused by intubation procedures, ventilator-induced barotraumas, and atelectasis. However, intraoperative anesthetic management requires sufficient analgesia and prevention of cough reflex and body movement, which places more stress on anesthesiologists in comparison with general anesthesia. Non-intubated VATS with regional anesthesia, such as PVB and infiltration anesthesia, causes fewer complications, including unstable postoperative hemodynamics and postoperative nausea and vomiting (PONV), in comparison with general anesthesia . There are no differences in complications or mortality, and pain control is good with regional anesthesia, which contributes to a decreased length of stay in the postoperative recovery unit and early ambulation and discharge from hospital .
PVB has a similar effect on postoperative analgesia to that of epidural anesthesia, but causes less intraoperative hypotension, and consequently has fewer complications, including urinary retention and PONV . Epidural anesthesia sometimes causes severe hypotension in patients with insufficient cardiopulmonary reserve due to cardiac dysfunction and low blood volume conditions. General anesthesia was considered to be difficult for case 1 due to poor respiratory conditions; however, he underwent thoracoscopic pleural biopsy in combination with PVB while awake. PVB provides analgesia in a lateral field with local anesthetic induction in the paraspinal space. Epidural anesthesia was initially considered to be possible; however, the patient complicated with moderate AS with cardiac dysfunction and low blood volume conditions. Consequently, epidural anesthesia was excluded considering risks for hypotension by bilateral sympathetic nerve block. PVB extension can be unpredictable , but the patient in case 1 frequently complained of pain when the apex of the lung was touched; therefore, it was better to transfer the PVB insertion point to the head side by 1 to 2 intercostal spaces. For case 2, the operation time was expected to be short and video-assisted empyema curettage with infiltration anesthesia, rather than epidural anesthesia and PVB, which block the sympathetic nerves, was performed based on possible respiratory failure and cardiac dysfunction.
Cough reflex disturbs surgical procedures in non-intubated VATS, but can be inhibited by continuous administration of lidocaine and preoperative inhalation of 2% lidocaine, ipsilateral stellate-ganglion block and intrathoracic vagal block [6, 7]. In case 1, lidocaine was not used to avoid local anesthetic poisoning due to excessive administration of local anesthetic and PVB. However, surgery was often interrupted by cough during extensive biopsy in the thoracic cavity. In case 2, based on the experience in case 1, lidocaine was used to prevent cough with consideration of the amount of local anesthesia required for extensive curettage of the thoracic cavity. In case 2, surgery was not interrupted by cough, indicating that procedures for preventing cough reflex should have been taken in case 1.
The two patients in the cases described here had cardiac dysfunction, low blood volume, and respiratory failure before surgery, and the possibility of postoperative cardiopulmonary deterioration due to general anesthesia, although they were likely to tolerate general anesthesia. Based on these conditions, we performed non-intubated VATS under local anesthesia in these two patients. Since intraoperative immobilization was necessary for non-intubated VATS, DEX was used for light sedation. Considering preoperative cardiopulmonary insufficiency and the nature of surgery, rapid administration of DEX has risks for unexpected hypotension and oversedation-induced airway obstruction. Therefore, continuous intravenous infusion was started without preloading after the patients entered the operating room. It took approximately 1 h to start the surgery after entry into the operating room, and the sedation level was maintained from RASS-1 to − 2 without respiratory problems.
Conversion of anesthesia for non-intubated VATS to general anesthesia occurs at a rate of 0–10% for reasons including pleural adhesion, continuous hypoxemia, hypercapnia, insufficient analgesia, and hemorrhage, which suggests that conversion may be needed at any time during surgery [5, 6]. Non-intubated VATS provides surgical treatment for patients with high risks for problems with respiration who generally find it difficult to tolerate general anesthesia. Furthermore, non-intubated VATS prevents ventilator-induced barotrauma and atelectasis due to general anesthesia, which may contribute to an improved prognosis, and improves the ventilation perfusion ratio mismatch for extension of the lower lung in a lateral position, compared to intubated VATS . Regarding the cardiovascular system, local anesthesia-assisted non-intubated VATS prevents general anesthesia drug-induced cardiac depression and vasodilation, leading to facile intra- and postoperative management of patients with cardiac dysfunction. For successful non-intubated VATS, it is important to ensure sufficient regional anesthesia to prevent cough reflex and body movement, which may cause risks in the surgical procedure.
We safely performed non-intubated VATS in combination with PVB and infiltration anesthesia in two patients with respiratory and hemodynamic failure. Regional anesthesia techniques in non-intubated VATS are likely to be useful for patients with respiratory failure and circulatory failure, but accumulation of more case reports is necessary for establishment of evidence for the efficacy of this approach.