Lung volume reduction surgery

Lung volume reduction surgery

Anesthesia type	GETA
Airway	DLT vs SLT w/ bronchial blocker
Lines and access	large bore PIV x2, A line, +/- central access/PA catheter
Monitors	Standard, 5 lead ECG, A line, +/- PA catheter
Primary anesthetic considerations
Preoperative	Medical optimization and strict patient selection is essential to prevent poor surgical outcomes
Intraoperative	Maintenance of physiologic parameters in the normal range may be very challenging due to poor reserve and synergistic interactions of comorbities
Postoperative	Extubation is anticipated, aggressive optimization prior to extubation in OR is necessary. Reduce coughing and bucking as much as possible to prevent worsening of air leaks. Tube exchange to SLT if mechanical ventilation is needed.
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Lung Volume Reduction Surgery (LVRS) is a surgical technique to help improve normal breathing in patients with emphysema by removing hyperinflated lung parenchyma. Up to 15-30% of lung parenchyma can be removed to achieve the desired results. Initially developed to help palliate the symptoms of end-stage emphysema, the technique initially showed promising results as well as severe operative morbidity and mortality. The National Emphysema Treatment Trial currently represents the best evidence supporting LVRS and provides basis for its approved indications. LVRS is a palliative procedure and does not reverse the disease process. It has been shown to improve FEV1, exercise tolerance, 6 minute walk test, and overall quality of life. These benefits are most significant in the first year postop, and return to preop baseline in 5 years.

Patients considered for this procedure with end stage emphysema will display decreased FEV1/FVC, absolute decrease in FEV1, hyperinflation, diaphragmatic flattening, and worsening work of breathing despite maximal medical therapy. Prior to surgery, preoperative pulmonary rehabilitation and smoking cessation are essential for a good surgical outcome. High resolution chest CT and V/Q scans can help with initial surgical evaluation by determining if a patient has upper lobe predominant, lower lobe predominant or homogeneous disease. From the NETT trial, patients with heterogenous upper lobe predominant disease demonstrated the most benefit from LVRS.

The selection criteria for LVRS is traditionally quite strict, with upwards of 80% of patients referred for LVRS rejected as surgical candidates. Preoperative screening is extremely important to optimize surgical outcome.

Inclusion Criteria:

Medical Hx:

• severe emphysema
• age < 75
• smoking cessation > 6mo
• lowest effective prednisone dose
• no prior thoracic surgery

Pulmonary function

• FEV1 < 30-35% predicted
• PaCO2 < 50mmHg
• TLC > 120% predicted

Cardiac function:

• mPAP < 35mmHg if pulm HTN suspected
• no evidence of LV dysfunction on stress testing if CAD suspected

Radiographic:

• hyperinflation w/ flattened diaphragm on CXR
• decreased upper lobe perfusion on V/Q scan
• emphysema with upper lobe predominance

Exclusion Criteria:

• continued smoking
• severe malnutrition
• other severe cardiopulmonary disease causing dyspnea (CAD, CHF, cancer, ILD, bronchiectasis)
• severe obesity or malnutrition
• previous thoracic surgery
• severe pulmonary hypertension (mPAP > 35)
• chest wall deformities with restrictive physiology

The surgical procedure entails the following steps:

1. Inspection/palpation of the entire lung with observation of the areas with most rapid deflation for preservation.
2. Mobilization of the entire lung
3. Resection of target areas with reinforced stapler. Reinforce staple lines with PTFE or bovine pericardium
4. Aggressive treatment of airleaks with sealants, pleural tents, or pleurodesis.

Preoperative management

Patient evaluation

System	Considerations
Cardiovascular	Elderly patients with longstanding COPD often have comorbid CAD, pulmonary HTN, and ischemic heart disease.
Pulmonary	Lung isolation is required for the procedure, and patients should have a thorough pulmonary evaluation to ensure that they will be able to tolerate at least some time on one lung ventilation. Smoking cessation and medical optimization of emphysema is a must prior to surgery.

Labs and studies

• Preoperative labwork, cardiac studies, and imaging will vary amongst patient populations. As in all cases, much of the preoperative studies will be based on individual patient H&P
• All patients should have a preoperative hemoglobin and type and screen on file prior to case start
• In patients with a history of cardiac disease or low functional status (most patients with end stage emphysema will qualify), consider additional cardiac testing with ECG, echo/stress echo. Any reversible ischemia should prompt further cardiac consultation
• Prior to surgery, high resolution CT, V/Q scan, PFTs, ABG and/or flow/volume loops will likely have been completed by the surgical team. Evaluation for tolerance of one lung ventilation is necessary.

Operating room setup

• Standard OR setup
• A-line
• Double lumen tube (left) vs bronchial blocker with SLT
• flexible bronchoscope for DLT placement
• fluid warmer in case transfusion is needed
• forced air warmer

Patient preparation and premedication

• ensure smoking cessation preop
• ensure all preop inhalers have been continued on the day of surgery.
• epidural or ESP catheter should be placed preoperatively for intraop and postop analgesia. Aggressive postop analgesia is extremely important to facilitate a favorable surgical outcome.

Regional and neuraxial techniques

• thoracic epidural is the preferred technique for intraop and postop analgesia, in patients without contraindications
• ESP catheters can also be placed for postop analgesia as an alternative to epidural technique.

Intraoperative management

Monitoring and access

• standard ASA monitors
• 5 lead EKG
• invasive hemodynamic monitoring with arterial line for BP and ABG monitoring
• 2 large bore PIV
• central access/PA catheter as indicated by history and physical (presence and degree of pulmonary HTN and RV dysfunction) and surgeon preference.

Induction and airway management

• Standard induction in patients with low aspiration risk.
• Lung isolation is required, and left double lumen tube is the preferred option for optimal isolation. Patients will often have very little pulmonary reserve and if placement of a DLT cannot be achieved swiftly, intubation with SLT with BB or subsequent tube exchange are also viable options.

Positioning

• The traditional open approach is typically taken through a median sternotomy in the supine position
• With thoracoscopic approaches (VATS-LVRS), patients are often placed in lateral decubitus, and flipped to address the other side.

Maintenance and surgical considerations

• patients are often quite chronically ill and often present a great challenge intraop to maintain normal physiologic parameters.
• standard maintenance with volatile or intravenous agents or balanced technique, along with administration of bolus/infusions through epidural.
• Avoid opioids if possible to reduce the risk of respiratory depression during emergence.

Emergence

• this is one of the most critical times during the surgery, optimize all physiologic parameters as much as possible. Early extubation is important for a good surgical outcome as prolonged mechanical ventilation will worsen air leaks.
• Optimize respiratory mechanics by sitting patient upright, maintaining good analgesia, deep suctioning prior to extubation
• Chest tubes are typically only kept on water seal because suction will maintain or worsen air leaks.
• coughing and straining on the ETT is undesirable as they may worsen air leaks, consider deep extubation techniques, bridging to other non-invasive ventilatory support until patients are wide awake, maintaining respirations with minimal support.
• If extubation is impossible or anticipated to be delayed, tube exchange to a SLT should be performed while the patient is well anesthetized and prior to transport to ICU.

Postoperative management

Disposition

• typically patients will recover in ICU even after extubation
• if postop mechanical ventilation is necessary, pressure support with low levels of CPAP may help with inspiratory work of breathing while controlling PaCO2 and airway pressure.

Pain management

• excellent postop analgesia is critical for good surgical outcome, as patients need early and aggressive pulmonary toilet and pulmonary rehabilitation
• epidural PCEA or ESP nerve catheters are typically used

Potential complications

• perioperative mortality is quite high, and is quoted at 5-15% in some series. No significant difference in outcomes have been shown between VATS vs median sternotomy approaches though patients operated with VATS approach have shorter recovery periods.
• virtually all patients will have air leaks, and may persist for longer than 7 days. Pleural pressure and pneumothoraces are manages with chest tubes that are kept on water seal. The chest tubes should NOT be placed on suction as they may worsen air leaks.
• Cardiac arrhythmias

Procedure variants

New bronchoscopic approaches with one-way endobronchial valves have been developed and are currently being studied for the palliation of end stage emphysema.