Nonintubated video-assisted thoracoscopic surgery (VATS) lobectomy to treat lung cancer has gained attention in recent decades, but there is very little literature on this topic. This review aims to explore the state-of-the-art, recent progress, and future prospects of this method. Its feasibility and safety have been demonstrated, and its potential benefits are faster postoperative recovery and fewer intubation-related complications. Nonintubated VATS lobectomy is a feasible and safe alternative for lung cancer treatment. This work provides information for those who would like to start using this technique and want a more comprehensive understanding of nonintubated VATS lobectomy.
Key points
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Nonintubated video-assisted thoracoscopic surgery (VATS) lobectomy is a feasible and safe alternative for lung cancer treatment.
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A variety of anesthetic techniques have been reported, and methods for managing the airway, analgesia, and sedation should be considered separately.
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Surgical techniques used for nonintubated VATS lobectomy are similar to those of the intubated approach.
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In the case of conversion, anesthesiologists should be familiar with bronchoscopic-guided intubation in the lateral decubitus position, although the reported incidence of conversion is low.
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Nonintubated VATS lobectomy may provide the benefits of faster postoperative recovery and fewer intubation-related complications, but oncologic outcomes have not been reported.
Introduction
The development of video-assisted thoracoscopic surgery (VATS) lobectomy using a nonintubation technique in the past decade has marked a new beginning for thoracic surgery. One century ago, before the introduction of endotracheal intubation and positive pressure ventilation, creating large openings in the chest wall, which causes pulmonary collapse, was considered fatal. Thoracic surgery was limited to chest wall procedures and drainage of pleural effusion because of the “pneumothorax problem.” At that time, pulmonary lobectomy was associated with a high mortality and was mostly indicated for infectious diseases, such as bronchiectasis and tuberculosis. The development of 1-stage lobectomy is considered to have begun with the work of Harold Brunn in 1929. In his case series that included 5 bronchiectasis cases and 1 lung malignancy case, Brunn described the details of lobectomy using local anesthesia and morphine preceded by barbital; he also mentioned the importance of cough suppression and keeping the diaphragm quiet during the procedure. All 6 patients survived the perioperative course, but 1 patient died of malignancy 9 months after surgery. This report was one of the earliest reports of “nonintubated” pulmonary lobectomy.
In the 1930s, the application of a cuffed endotracheal tube with controlled ventilation led to a substantial revolution in the field and enabled deeper anesthesia to eliminate spontaneous respiration of the patients and provide a quiet surgical field. During the following decades, advances were made in airway management, 1-lung ventilation, and mechanical ventilators; in addition, invasive and noninvasive intraoperative monitoring, the introduction of multiple anesthetic agents, and an understanding of pulmonary physiology and anatomy have contributed to the evolution of anesthesia for thoracic surgery. Intubated general anesthesia with 1-lung ventilation is considered the standard for thoracic surgery, and lung cancer has surpassed infectious diseases as the main indication for lobectomy. The advent of VATS began another revolution in thoracic surgery, and the first VATS lobectomy was reported in 1992. As surgeons continued developing other minimally invasive techniques during the modern era, Pompeo and colleagues, in 2004, first proposed the resection of pulmonary nodules by awake VATS without endotracheal intubation to prevent intubation-related complications and ventilator-induced lung injury. In 2007, Al-Abdullatief and colleagues reported a retrospective observational study of awake anesthesia for major thoracic surgeries, including 3 lobectomies. The detailed techniques of nonintubated VATS (NIVATS) lobectomy to treat lung cancer were first reported by Chen and colleagues in 2011. Over the years, other groups have described modifications and a variety of analgesia strategies, including different types of airway management, analgesia, and sedation methods. In this work, the authors review current literature regarding the techniques and outcomes of NIVATS lobectomy to treat lung cancer, its unsolved problems, and its future prospects.
Indications and contraindications
Patients considered suitable for NIVATS lobectomy for lung cancer have clinical stage I or stage II disease and a tumor smaller than 6 cm in diameter, without evidence of chest wall, diaphragm, or main bronchus involvement. Common contraindications are listed in Table 1 ; these mainly include oncologically unsound conditions or conditions rendering the nonintubated procedure unsafe. Extensive pleural adhesion or previous thoracic surgery contraindicates neither VATS lobectomy nor the nonintubated approach. Patients with poor pulmonary function at high risk for intubated general anesthesia are considered ideal candidates for the nonintubated approach for minor thoracic surgery. , Wang and colleagues reported the feasibility of NIVATS lobectomy in patients with impaired pulmonary function. However, because extremely poor lung function (forced expiratory volume in 1 second [FEV 1 ] <30% or diffusing capacity of the lung for carbon monoxide [DLCO] <30%) is considered a contraindication for VATS lobectomy because of the possibility of postoperative respiratory failure, these conditions are also regarded as contraindications for the nonintubated approach. Obesity is associated with higher respiratory rates and lower tidal volumes, and obese patients are more likely to develop faster and deeper respiratory movements during nonintubated anesthesia. In a recent study by Hung and colleagues that included 1025 NIVATS lung tumor resections, body mass index (BMI) ≥25 kg/m 2 was found to be a risk factor for conversion to intubation. In many studies, BMI greater than 30 was considered an exclusion criterion for NIVATS. ,
| Contraindications for VATS Lobectomy | Contraindications for Nonintubated Approach |
|---|---|
| ASA score >3 Bleeding disorder FEV 1 <30% DLCO <30% Centrality of tumor if invading hilar structure(s) Severe cardiopulmonary dysfunction | Sleep apnea Unfavorable airway anatomy High risks for gastric reflux Underlying neurologic or mental disorders BMI >30 Known allergy to local anesthetics Expected extensive pleural adhesion Unstable asthma Spine deformities (if TEA is to be used) |
Preoperative assessment
The medical history of the patient should be carefully reviewed. Diagnostic evaluation and staging of the oncologic status are routinely performed, including laboratory hemograms, chemistry and coagulation profiles, imaging of the chest and upper abdomen with contrast-enhanced computed tomography (CT), integrated whole-body PET /CT, bone scan, and imaging of the brain with MRI or CT. A pathologic diagnosis is made according to preoperative biopsy or intraoperative frozen section results. A pulmonary function test should be performed, and an echocardiogram is indicated if the patient reports related symptoms or is elderly. Factors predictive of difficult intubation, such as an unfavorable airway, should be evaluated before surgery. The surgical team, including the surgeon and anesthesiologist, should evaluate the patient and reach a consensus. The patient should be informed of the risks and benefits of the nonintubated approach.
Anesthetic techniques
Airway Management
The most important concepts of “awake” or “nonintubated” VATS are avoidance of tracheal intubation and muscle relaxants and maintenance of spontaneous breathing. Choices for airway management during NIVATS include the following:
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Face mask: During early studies of NIVATS, a face mask was used to keep the oxygen saturation (Sp o 2 ) higher than 90% during surgery. No significant differences in the lowest detectable mean Sp o 2 and peak end-tidal carbon dioxide in intubated and nonintubated groups were found. However, intraoperative hypoxemia was still a concern and may result in conversion to intubated general anesthesia.
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Laryngeal mask airway (LMA): In 2012, Ambrogi and colleagues first reported a preliminary experience with VATS for patients under general anesthesia and spontaneous breathing with LMA. Later, the same group presented the feasibility and safety of this technique for VATS resection of lung nodules. No desaturation was noted, even for older patients with chronic obstructive pulmonary disease (COPD) or patients heavier than 100 kg. The benefits include the ability to use general anesthesia with inhalation anesthetics, thus permitting positive pressure ventilation if breathing depression develops, and the ability to use LMA-aided tracheal intubation to obtain an endotracheal airway if conversion is indicated.
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High-flow nasal cannula (HFNC): HFNC with transnasal humidified rapid-insufflation ventilatory exchange with a flow rate of 20 L/m effectively increases the oxygen reserve and safety margin during NIVATS ( Fig. 1 ).
Fig. 1
Anesthetic settings of nonintubated thoracoscopic surgery. The patient was sedated with propofol and breathed through an HFNC.
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Oropharyngeal cannula: Some groups prefer an oropharyngeal cannula with a tip that lies immediately above the vocal cords to effectively increase the oxygen concentration of inspirated air.
Locoregional Anesthesia
The most common techniques for analgesia during NIVATS lobectomy are thoracic epidural anesthesia (TEA) and intercostal nerve blocks (ICNB). To achieve a sensory block between T2-9 while maintaining diaphragm movement, the usual level of epidural catheter insertion is at T4-T6. However, the TEA technique is time consuming and technically demanding, and it may cause unwanted complications. An ICNB can be used to prevent TEA-related complications. Hung and colleagues reported a retrospective cohort study of 238 cases that was performed to compare TEA and ICNB for NIVATS lobectomy for lung cancer; they found no difference in postoperative analgesia. ICNB can be performed easily and quickly, does not cause hemodynamic instability, and does not create a risk for spinal cord injury. Usually, local anesthetic agents are infiltrated under direct thoracoscopic vision from the third to the eighth intercostal nerves after creation of the first thoracoscopy port; bupivacaine is the most widely used ( Fig. 2 ).
Sedation
The depth of sedation is a continuum in NIVATS, from mildly sedated but communicable and cooperative to a sedation level of general anesthesia. Whichever depth of sedation is applied, the patients should be monitored closely to ensure that they maintain a respiration rate between 12 and 20 breaths/min. NIVATS lobectomy can be performed with the patient awake, as reported by Al-Abdullatief and colleagues and Chen and colleagues. , However, to decrease patient anxiety and to provide a more stable and controlled surgical environment for surgeons, deeper sedation with target-controlled infusion of propofol and/or remifentanil and bispectral index monitoring to maintain a target of 40 to 60 is favored by most groups. , , , A bispectral index range of 40 to 60 corresponds to a hypnotic state of general anesthesia while spontaneous breathing is maintained. Some investigators used incremental or continuously infused remifentanil to slow the respiratory rate and suppress the cough reflex. , For patients with LMA for ventilation support, inhalatory agents, such as sevoflurane, can be used for analgesia instead of intravenous hypnotic drugs.
Cough Suppression and Vagal Nerve Block
VATS lobectomy involves bronchial manipulation, which may induce an unwanted cough reflex during nonintubated surgery. Dissection of vascular structures without cough control is not safe because of the risk of major bleeding. The cough reflex is controlled through either intrathoracic vagus nerve infiltration or preemptive inhalation of nebulized lidocaine 2% for 30 minutes before surgery. However, because vagal block is effective for diminishing the cough reflex, easy to perform, and associated with low risks, it is the authors’ preferred option. Vagal block is usually performed with intrathoracic administration of 2 to 3 mL 0.5% bupivacaine to the vagus nerve at the level of the lower trachea for right-sided procedures and at the level of the aortopulmonary window for left-sided procedures (see Fig. 2 ).
Surgical techniques
The surgical setting for NIVATS lobectomy is similar to that for intubated VATS lobectomy. Patients are placed in the lateral decubitus position. Traditionally, VATS lobectomy is performed using a 3-port method, as described by McKenna. After creation of the first skin incision under local anesthesia, the lung is collapsed gradually to enable further application of ICNB or intrathoracic vagal block. Further procedures are consistent with those of conventional VATS ( Fig. 3 ). Systemic lymph node dissection includes more than 3 stations of the mediastinal lymph nodes. When the procedure has been completed, manually assisted mask ventilation is provided to reexpand the lung after closure of the surgical wounds with sutures. Alternatively, if the patient is oxygenated with an HFNC, then a high flow of oxygen at 70 L/min can be provided; if an LMA is used, then positive pressure ventilation can be applied. Suction via the chest tube can also be used to help lung expansion.
