Spontaneous ventilation vs. general anesthesia
General anesthesia with one lung ventilation was considered necessary for lung resections, mainly because the surgeon can operate with non-ventilated lung and no breathing expansion. However, it has been demonstrated that general anesthesia and mechanical ventilation have a large series of potential side effects that could influence patients’ post operative morbidity and mortality, their length of the hospital stay and post-operative quality of life. Indeed, mechanical ventilation could lead to a lung damage because of an airway pressure-induced injury, atelectasis in the non-ventilated lung, the release of pro-inflammatory mediators (7–10). General anesthesia, use of muscle relaxant and use of opioids could cause a prolonged hospital stay and an augmented risk of mortality and morbidity and post operative cognitive dysfunction (11–13). In addition, orotracheal and bronchial intubation have potential, not insignificant, complications such as post-op throat pain or laryngeal and/or tracheal injuries (14).
Surgical pneumothorax in non-intubated thoracic surgery requires the anesthesiologist to manage the paradoxical ventilation and the risk of hypoxemia, due to a potential increase of the right-left intrapulmonary shunt. Hypoxic pulmonary vasoconstriction, a defense mechanism which is activated by the hypoxic alveoli, is more efficient during NITS, since we do not use some anesthetic drugs, like volatile anesthetics that can inhibit the protective vasomotor response of HPV (15). Furthermore, the anesthesiologist must avoid severe hypercapnia and acidosis during the awake thoracic surgery. Patients with a background of severe COPD or neuromuscular diseases have a higher risk for developing intraoperative hypercapnia. However, transient perioperative permissive hypercapnia has been well described (16).
Cough reflex, triggered by lung manipulation, could be the surgeon’s ‘enemy’ during NITS: in the last years several techniques were developed to reduce this reflex: inhalation of aerosolized lidocaine, application of a spray of lidocaine on the lung surface, a stellate ganglion block or a vagus nerve block placed intrathoracically were all feasible techniques (16).
Thoracic surgery in non-intubated patients was already known in the 1920s, when Jacobeaus began to use thoracoscopy in patients with a suspected tuberculosis or other intrathoracic diseases to make diagnosis and to perform cauterization of adhesions in awake patients (17). After all, mechanical ventilation was not introduced before the 1960s and patients’ survival after a thoracotomy in spontaneous ventilation was extremely low. At the end of the ‘50s, high number cases studies have been published reporting awake anesthesia techniques for major lung resections that have subsequently inspired current techniques (18, 19). With the introduction of the mechanical ventilation in early 1960s and mainly with the introduction of the double lumen tube, the one lung ventilation with a controlled general anesthesia became the gold standard for thoracic surgery. At the beginning of the XXI century, thoracic surgeons started to question themselves about the feasibility of lung resections avoiding general anesthesia. The first study was undertaken by Pompeo et al., who published a small randomization of 60 patients who underwent a wedge resection in general anesthesia (control group) or without it, with sole thoracic epidural anesthesia (awake group) and providing oxygen via a face mask. They demonstrated that the awake group had a significant reduced hospital stay, a greater anesthesia satisfaction score and a significantly lower post-operative ΔPaO2 (1). Since then, there has been a growing interest in this technique: only three years later, in 2007, Al-Abdullatief et al. published an observational study showing the possibility to perform awake anesthesia also in some cases of major thoracic resection, emphasizing above all the importance of avoiding muscle relaxants during thymectomies in patients with myasthenia gravis (20). In 2012, Chen et Al. published an important work showing a 3-years’ experience of non-intubated lung resection with 285 cases, of which 159 (55.8%) patients for primary lung cancer. They reported only fourteen (4.9%) conversion to tracheal intubation and no perioperative mortality (21). First applied for wedge resection, lung biopsies, metastasectomies (22) and lung volume reduction surgery (23, 24), the awake technique had a high development in the last years and recent studies reported the use of awake anesthesia for major lung resection (5) and even during thoracotomy (25), without significant differences in terms of survival and post-operative mortality, but with a faster recovery after surgery and a low rate of conversion to general anesthesia (0%–3%) (26). Awake lung biopsies still play a leading role in diagnosis of interstitial lung disease although the increasing diffusion of cryobiopsy, that still have a lower diagnostic yield compared to surgery (27).
In this study we reported a single center’ preliminary experience and early post-operative outcomes of awake U-VATS sublobar lung resection performed between September 2021 and September 2022. We performed n = 8 wedge resections and n = 2 segmentectomies (one lingulectomy and one S6 left segmentectomy) for NSCLC, without post-operative major complications. Only n = 5 (50%) patients needed an ICU post-operative monitoring with a mean time of 17.20 h. We reported length of stay and chest tube duration values higher than other results in literature (26), mainly because we selected high comorbidities’ patients for our awake lung resections. Indeed, this kind of patients would have been difficult to enroll for lung surgery under general anesthesia, due to the higher risk of post-operative complications, morbidity, and mortality.
This study has several limits: first, it is a single-center retrospective analysis of a small cohort of high-selected patients. Reporting early post operative outcomes, we cannot include overall and event-free survival in our results. We are carrying out a larger follow-up of these patients and updated results may be published in the future.