Video-assisted thoracoscopic surgery

Video-assisted thoracoscopic surgery

Anesthesia type	General (rarely, monitored anesthesia care for selected cases)
Airway	Double-lumen endotracheal tube or bronchial blocker
Lines and access	Adequate peripheral IV access; consider arterial line
Monitors	Standard; consider arterial monitoring
Primary anesthetic considerations
Preoperative	Pulmonary function testing, prehabilitation to optimize pulmonary status; consider thoracic epidural catheter
Intraoperative	One-lung ventilation; protective ventilation strategies; conservative fluid administration
Postoperative	Pain control, pulmonary hygiene
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Anesthesia for minimally invasive, video-assisted or robotic-assisted thoracoscopic surgery (VATS), is similar to anesthesia for open thoracic cases in many respects. However, achieving lung isolation quickly and completely is even more important, since even a slightly inflated lung may obstruct the surgeon’s view. Procedures that are amenable to VATS include but are not limited to:

• Mediastinoscopy
• Wedge resection or lung biopsy
• Lobectomy or segmentectomy, including bronchial sleeve resection
• Lymph node dissection
• Pleurodesis, mechanical or talc, for pleural effusion or spontaneous pneumothorax
• Decortication, including evacuation of empyema or hemothorax
• Thymectomy
• Lung volume reduction for severe emphysema
• The intrathoracic portion of esophagectomy
• Thoracic sympathectomy for hyperhidrosis or treatment of refractory ventricular tachycardia
  

Nearly any patient may be a candidate regardless of extremes of age or pulmonary disease. 

Procedures usually requiring open thoracotomy include pneumonectomy, intrathoracic tracheal resection, and chest wall resection. 

The advantages of VATS include decreased hospital length of stay, decreased morbidity, and less postoperative pain.

The keys to anesthesia success include:

• Availability of video laryngoscopy to facilitate intubation;
• Facility with placing both right and left endobronchial tubes;
• Skill with fiberoptic bronchoscopy;
• Having a dedicated team of personnel with expertise in thoracic anesthesiology.

Primary anesthetic considerations include optimal double-lumen tube placement with fiberoptic guidance, management of one-lung ventilation to avoid hypoxia and unnecessary hyperoxia, and use of protective ventilation strategies to avoid injury to the ventilated lung. Acute lung injury following thoracic surgery may lead to the development of ARDS with potentially lethal outcomes.

Preoperative management

Patients may present for VATS in sound health or with substantial disease burden.

A young, otherwise healthy patient who presents for thoracic sympathectomy for hyperhidrosis, or bleb resection with mechanical pleurodesis for recurrent spontaneous pneumothorax, may require no preoperative testing.

At the opposite extreme, patients may present with COPD, decreased lung function on the affected side, pleural or pericardial effusion, anemia, poor nutritional status, and effects of neoadjuvant chemotherapy and/or radiation. Whenever possible, prehabilitation in preparation for surgery should be considered to correct anemia, improve nutritional status, and improve functional capacity.

Patient evaluation

System	Considerations
Cardiovascular	Evidence of ventricular or valvular dysfunction, pulmonary hypertension
Respiratory	History of COPD, asthma, pleural effusion, pulmonary fibrosis, sarcoidosis, other pulmonary pathology
Neurologic	Peripheral neuropathy due to chemotherapy; evidence of myasthenia or paraneoplastic syndrome; assess appropriateness for epidural analgesia
Gastrointestinal	Evidence of carcinoid syndrome in cases of lung or endobronchial carcinoid tumor
Hematologic	Hypercoagulability due to underlying malignancy

Labs and studies

1. Routine preoperative laboratory, EKG, and radiographic studies as appropriate for patient age and institutional guidelines
2. Consider pulmonary function testing
3. Consider echocardiography, stress testing
4. Consider ventilation/perfusion (v/q) scan before major lung resection

Operating room setup

1. Double-lumen endotracheal tube (DLT) or endobronchial blocker as appropriate
2. Fiberoptic bronchoscope
3. Video laryngoscope -- may facilitate DLT insertion
4. Consider arterial line setup and transducer

Patient preparation and premedication

Patients should fast per institutional guidelines. Premedication is at the choice of the anesthesiologist depending on the patient's age and other relevant factors.

Regional and neuraxial techniques

Thoracic epidural analgesia may be considered especially if bilateral VATS is undertaken or if the surgeon thinks there is a high likelihood that conversion to open thoracotomy may be necessary.

The epidural catheter should be inserted at a high enough level that the patient will not have any lumbar motor block and can safely ambulate. Insertion prior to surgery offers the advantage of beginning continuous epidural infusion before the patient emerges from anesthesia. Some anesthesiologists prefer to utilize the epidural infusion along with general anesthesia for the entire case. Others prefer to activate the epidural catheter only near the end of surgery once blood loss is over in order to avoid intraoperative hypotension. There is no conclusive evidence that either approach is superior.

If the patient has a contraindication to epidural catheter placement, other regional techniques may be considered for postoperative pain relief: lumbar spinal opioid analgesia, erector spinae plane block, intercostal or paravertebral blocks.

Intraoperative management

The goals of intraoperative management include:

1. Optimal placement of DLT for effective one-lung ventilation
2. Avoidance of hyperoxia which may be an exacerbating factor in acute lung injury
3. Maintaining satisfactory peak airway pressure (preferably less than 25-30 cmH20) and plateau pressure during one-lung ventilation; permissive hypercapnia may be necessary to avoid barotrauma to the ventilated lung
4. Avoiding excessive administration of crystalloid which been associated with acute lung injury

Monitoring and access

Standard monitors suffice for induction for many patients. Patients presenting for less invasive procedures may not require any more than standard monitoring for the duration of the case; examples might include thoracic sympathectomy for hyperhidrosis, limited lung biopsy for tissue diagnosis, talc pleurodesis for palliation of recurrent pleural effusion, or placement of PleurX catheter.

Arterial monitoring is commonly performed for lung resection, esophagectomy, thymectomy, and other major operative procedures. It enables continuous observation of blood pressure, and arterial blood gas measurement if indicated. Whether the arterial catheter should be inserted prior to or after anesthesia induction is a matter of anesthesiologist preference.

As the administration of fluids is best kept to a modest amount for lung resection, more than one well-functioning peripheral IV catheter may not be necessary. This again is a matter of individual judgment and preference.

Central venous pressure or flow parameter monitoring (e.g. FloTrac, Edwards Lifesciences) may be considered for patients undergoing procedures where substantial blood loss and/or fluid requirements are likely, such as esophagectomy or pleurectomy/decortication. A central venous line may be indicated in any procedure if peripheral veins are inadequate.

Induction and airway management

1. Induction medications and muscle relaxant choice per anesthesiologist preference. Ketamine may be a useful adjunct, especially for patients with chronic pain or a history of preoperative opioid use.
2. DLT (typically 35-39 Fr) is inserted and position confirmed with fiberoptic bronchoscopy. Selection of the DLT size is dependent on patient height and weight. A 37 Fr DLT is suitable for most average-size female patients, and 37-39 Fr for most male patients. DLT smaller than 35 Fr does not easily accommodate a fiberoptic bronchoscope.
3. Alternatively, an endobronchial blocker may be inserted through a single-lumen ETT.
4. The selection of right or left DLT is dependent on the situation and on user experience. One absolute indication for a R DLT is the planned sleeve resection of a L mainstem tumor (Fig. 1).
5. During any lung resection procedure on the left lung, several factors argue in favor of placing a R DLT:

• ·    There is no risk of stapling the tube to the bronchus during lobectomy or pneumonectomy, which can lead to fatal complications. ·      The surgeon has a complete view of the carina and mainstem bronchus on the operative side during bronchoscopy. ·      There is no need to insert a single-lumen tube for bronchoscopy and/or mediastinoscopy and then change to a DLT. ·      If the tracheal cuff tears on the patient’s molars, the bronchial cuff will still guarantee lung isolation. ·      The tracheal lumen is always the one occluded during lung isolation, so it is easy to look down the tracheal lumen with a bronchoscope to check the position of the blue (bronchial) cuff without interrupting ventilation. ·      With left lung surgery and a left DLT, the tracheal orifice may be pushed against the tracheal wall and occluded. ·      With left lung surgery and a left DLT, pressure on the operated lung may dislodge the bronchial cuff and push it out into the trachea, losing lung isolation.

Figure 1: Malignant mucoepidermoid tumor in L mainstem bronchus near the main carina, with R DLT in position

Procedure variants

	Variant 1	Variant 2
Unique considerations
Position
Surgical time
EBL
Postoperative disposition
Pain management
Potential complications