What the Anesthesiologist Should Know before the Operative Procedure

Chronic obstructive pulmonary disease (COPD) is characterized by progressive and largely irreversible airflow limitation caused primarily by exposure to tobacco smoke and less commonly by other noxius stimuli or by alpha1-antitrypsin deficiency.

The cardinal abnormality in COPD is an irreversible reduction in maximal expiratory flow due to chronic bronchitis, emphysema or both.

Chronic bronchitis is defined as cough and sputum production for most days over 3 months for 2 consecutive years. It is thought to result from the innate immune response to inhaled toxic particles and gases, particularly to tobacco smoke which results in inflammation of the epithelium of the central airways and mucus-producing glands. The airway inflammation is associated with increased mucus production, reduced mucociliary clearance, and increased permeability of the airspace epithelial barrier.
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Emphysema is defined as enlargement of the airspaces, distal to the terminal bronchioles, due to destruction of the alveolar walls. Destruction of the normal lung parenchyma causes a reduction of the elastic recoil resulting in a progressive deterioration of the maximal expiratory airflow. Emphysema may exist in two forms: (1) centrilobular or centriacinar form results from dilatation or destruction of the respiratory bronchioles, is more closely associated with tobacco smoking and has predominantly an upper lobe distribution, and (2) panlobular, or panacinar form, results in more even dilatation and destruction of the entire acinus, is associated with alpha1- antitrypsin deficiency and has predominantly a lower lobe distribution.

Expiratory airflow limitation and parenchimal destruction result in:

reduction in the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC). The diagnosis of COPD as established by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) requires an FEV1/FVC ratio of <0.7, and patients are then stratified into four categories from mild to very severe disease based on the severity of FEV1 impairment.
reduction in FEV1. Patients with severe COPD have an FEV1<50% predicted and patients with very severe COPD have an FEV1<30% predicted or <50% with chronic respiratory failure.
air trapping and hyperinflation with increases in total lung capacity (TLC) and residual volume (RV), an elevated RV/TLC ratio, and functional residual capacity (FRC)
dynamic hyperinflation or “stacking” of breaths during exercise when ventilatory requirements are increased
ventilation-perfusion (V/Q) mismatch and impairment of gas exchange due to acinar destruction and compression of the normal parenchyma by hyperinflation.
mild-to-moderate pulmonary hypertension and mildly impaired right ventricular function

In spite of the advances in medical therapy, smoking cessation is the single most effective intervention shown to alter the rate of progression of COPD. The failure of medical management of COPD to produce significant impact on outcomes has led to the development of lung volume reduction surgery (LVRS). In selected patients with severe emphysema, LVRS was associated with prolonged survival, improvement in exercise capacity and quality of life, and improvement in lung function and dyspnea.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

LVRS is performed strictly on an elective basis. Given the high perioperative mortality and morbidity associated with LVRS, the survival benefit depends on adequate patient selection. The patient selection criteria are rigorous involving both functional and radiological assessment with the goal to identify the patients that are most likely to benefit from the procedure with an acceptable risk, to optimize medical status and customize perioperative risk reduction strategies. These patients also benefit from pulmonary rehabilitation and smoking cessation for at least 6 months prior to surgery.

2. Preoperative evaluation

Preoperative clinical evaluation should be focused on:

identifying the clinical manifestations of the lung disease
presence of comorbid diseases
active cigarette smoking
corticoteroid use
nutritional status

COPD is associated with high rates of other comorbid illnesses such as cardiovascular disease, malnutrition, cachexia, peripheral muscle weakness and osteoporosis.

Preoperative evaluation relies also on:

pulmonary function tests
arterial blood gas
high-resolution computer tomography
ecocardiography/right heart catheterization

Discussion regarding preoperative evaluation will be detailed below.

3. What are the implications of co-existing disease on perioperative care?

b. Cardiovascular system

Coronary artery disease (CAD) is frequent among patients with COPD as the two diseases share cigarette smoking as a common risk factor. The evaluation of patients with advanced emphysema for the presence and extent of coronary artery disease may be challenging as these patients may have poor functional capacity due to the underlying lung disease. Given the fact that elective pulmonary resection is considered a surgical procedure of “intermediate risk” by the American College of Cardiology(ACC)/American Heart Association(AHA) guidelines, Noninvasive cardiac testing should be considered based on the presence of patient-specific clinical predictors of myocardial risk as recommended by the American College of Cardiology(ACC)/American Heart Association (AHA) guidelines. Patients who have evidence of significant ischemia on noninvasive testing usually undergo coronary angiography; those who have left main or triple-vessel disease are potential candidates for surgical revascularization, whereas those who have single- or double-vessel disease may undergo percutaneous coronary intervention (PCI) with or without stenting or be managed medically. A recent myocardial infarction (within the past 30 days) represents a major risk factor for perioperative risk complications. Although in the past, it was believed that elective surgery should be delayed for 6 months after a myocardial infarction based on Goldman’s original risk index, the ACC/AHA guidelines have decreased this interval to 4 to 6 weeks for a medically stable, fully investigated and optimized patient.
As multiple clinical scenarios (hypoxemia, hypercarbia, dynamic hyperinflation) can lead to exacerbation of pulmonary hypertension and right ventricular failure, the degree of pulmonary hypertension should be evaluated either noninvasively or invasively. As echocardiography is frequently inaccurate in patients with advanced lung disease and tends to considerably overestimate the degree of pulmonary hypertension a right heart catheterization is sometimes required in order to rule out significant pulmonary hypertension.

c. Pulmonary

The criteria for lung resection in patients with emphysema have developed over time. The National Emphysema Treatment Trial (NETT), a multi-institutional randomized study sponsored jointly by the National Heart, Lung and Blood Institute and the Center for Medicare and Medicaid Services, provided reliable estimates of risk and benefit from LVRS and established criteria selection for patients who will benefit most from lung volume reduction.

Percent-predicted FEV1 is one of the predictors of major pulmonary morbidity. The upper limit of FEV1 should be between 35 and 45% predicted. A higher postbronchodilator FEV1 would not justify the risks associated with LVRS. The lower acceptable limit of FEV1 was not defined before the NETT. The NETT defined a group of patients with severe emphysema who should not have surgery because of an exceptionally high risk for death after LVRS with little chance of functional benefit. This group of patients had an FEV1 less than 20% of the predicted value and either homogenous (diffuse) emphysema on chest computed tomography (CT) or a DLCO less than 20% of the predicted. Based on this data, the NETT investigators ceased the enrollment of patients with low FEV1 who had either homogenous emphysema on the chest CT scan or a low carbon monoxide diffusing capacity
In the NETT patients not considered to be high risk, DLCO together with FEV1 and age were found to be risk factors for major pulmonary morbidity, defined as tracheostomy, failure to wean from mechanical ventilation, reintubation, pneumonia and mechanical ventilation for 3 days or more. A lower limit of DLCO varying between 10% and 30% of the predicted has been observed in other studies to increase the risk of mortality and morbidity.
Arterial blood gases abnormalities have also been suggested as predictive of a bad outcome with significant controversies surrounding this issue. Data regarding oxygenation are contradictory with no real correlation between preoperative oxygenation and outcome. However, the NETT excluded patients with oxygen requirement greater than 6 L/min to maintain oxygen saturation more than 90% during exercise. Data regarding the prognostic value of preoperative PaCO2 on perioperative mortality and morbidity is also conflictual. The NETT data did not reveal hypercapnia to be a predictor of worse outcome, however patients with a PaCO2 greater than 60 mmHg (55mm Hg in Denver) were excluded from the trial, by trial design.
High-resolution computer tomography (HRCT) is a powerful tool for evaluation of pulmonary emphysema and has become the radiographic study of choice in evaluation potential LVRS patients based on the findings of the NETT. In the NETT, the magnitude and distribution of the emphysema in the participating patients was classified by HRCT as predominantly upper-lobe or non-upper-lobe using a visual scoring scale according to the study protocol. Based on the combinations of upper-lobe emphysema or non-upper-lobe emphysema and low or high exercise capacity at baseline, the patients in the NETT were divided in four groups. When compared to maximal medical therapy, LVRS provided the most survival advantage and improvement in exercise capacity in patients with upper-lobe disease and low exercise capacity at baseline. Patients who had non-upper-lobe emphysema and high baseline exercise capacity undergoing LVRS had a higher risk of death compared with medical therapy but showed a greater improvement in exercise capacity and health-related quality of life. As mentioned above patients with an FEV1<20% predicted and with either diffuse emphysema on HRCT or DLCO<20% predicted had an increased risk of surgical mortality.
Patients considered for LVRS should undergo pulmonary rehabilitation which has been shown to improve exercise capacity, dyspnea, and health-related quality of life. Also, LVRS candidates should be nonsmokers for at least 6 months prior to surgery. As some patients may have partially reversible airways disease, maximal medical therapy with long-acting bronchodilators and mucolytics should be continued including on the day of the surgery. Patients must be free of respiratory infections for at least 3 weeks before lung volume reduction surgery and must require no antibiotic therapy preoperatively. As systemic steroids have been linked to possible increased risks for perioperative delayed wound healing and infectious complications, they should be weaned off or decreased to the lowest possible dose. A daily corticosteroid dose of more than 20 mg (or equivalent) was one of the exclusion criteria in the NETT.

d. Renal-GI:

Patients with preexisting renal disease are at increased risk for developing acute renal failure. Fluid restriction in the setting of one-lung ventilation may predispose these patients to worsening of their renal function. Nonsteroidal anti-inflammatory drugs (e.g., ketorolac) for postoperativepain control should be avoided in these patients.

e. Neurologic:

N/A

f. Endocrine:

N/A

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

N/A

4. What are the patient's medications and how should they be managed in the perioperative period?

Due to coexisting morbidities, especially coronary artery disease, patients presenting for LVRS may have a complicated treatment plan including:

-antihypertensives

-medications for coronary artery disease

-bronchodilators

-steroids

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

As some patients may have partially reversible airways disease, maximal medical therapy with long-acting bronchodilators and mucolytics should be continued including on the day of the surgery.
Patients must be free of respiratory infections for at least 3 weeks before lung volume reduction surgery and must require no antibiotic therapy preoperatively.
Systemic steroids have been linked to possible increased risks for perioperative delayed wound healing and infectious complications and they should be weaned off or decreased to the lowest possible dose. A daily corticosteroid dose of more than 20 mg (or equivalent) was one of the exclusion criteria in the NETT.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac:

Antihypertensive medication is continued into the perioperative period. Angiotensin converting enzyme inhibitors and angiotensin receptor blockers are a cornerstone of therapy for congestive heart failure and are important in the therapy of hypertension and coronary artery disease. In the perioperative setting, induction of general anesthesia in patients with angiotensin blockade may result in significant hypotension requiring the administration of vasopressors. Withholding angiotensin blockade for 10 hours or more before surgery may result in less intraoperative hypotension.

Pulmonary:

It is paramount to continue pulmonary treatment (bronchodilators, mucolytics) including in the morning of surgery to ensure stable pulmonary function.

Anti-platelet agents:

Continuation of anti-platelet drug therapy depends on individual patient risk factors (presence and type of stents, lapse of time since the stent placement, presence of peripheral vascular disease, etc). After bare-metal stent placement, elective surgery should be postponed for 4-6 weeks for proper dual antiplatelet therapy (aspirin and clopidogrel) to allow stent endothelization and reduce the risk of coronary stent thrombosis. For drug-eluting stents it is recommended that elective noncardiac surgery be delayed for at least 12 months due to delayed endothelization and risk for early and late stent thrombosis with premature discontinuation of dual antiplatelet therapy. Generally, if clopidogrel is discontinued, aspirin can be continued safely in the perioperative period.

j. How To modify care for patients with known allergies –

Prevention of anaphylactic reactions relies mainly on accurate documentation of previous reactions and avoidance of the incriminated drug. During preanesthetic consultation, a detailed history should be taken with special emphasis on atopy, drug allergy, and allergy to latex. Neuromuscular blocking agents, latex and antibiotics are the most frequently involved drugs. Pretreatment with H1 and H2 receptor antagonists may reduce histamine-mediated adverse effects associated with muscle relaxant and vancomycin administration but may not obliterate completely the allergic reaction due to the release and presence of other dangerous mediators. No evidence of beneficial effects of the prophylactic administration of corticosteroids in allergic reactions to anesthetic drugs have been shown. Pretreatment with corticosteroids, antihistamines, or both does not reliably prevent immune-mediated reactions.

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

Latex-sensitive patients should be managed by complete avoidance of potential latex exposure. Patient care must be carefully coordinated among all professionals, including pre- and postoperative nursing and operating teams. Whenever possible, the patient should be scheduled for elective surgery as the first case of the day to reduce exposure to aerosolized latex particles. Warnings identifying a risk for latex allergy should be posted inside and outside the operating room and in perioperative care areas. Resuscitation drugs should be readily available.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

General anesthesia ensures adequate control of the airway, control and monitoring of ventilation, and control of patient movement. However general anesthesia has multiple adverse effects on respiratory mechanics and blood gas exchange irrespective of the anesthetic agent used.

Patients with COPD develop minimal or no atelectasis during anesthesia, experience only a minor decrease in functional residual capacity (FRC) and a small shunt. There is, however, a large dispersion of V/Q ratios with a further increase in V/Q mismatch and a widened perfusion distribution. Carbon dioxide elimination might also be impaired during anesthesia due to increased distribution of ventilation to areas of the lungs with high V/Q ratio.
All inhalational agents, opioids and most intravenous anesthetic agents attenuate hypoxic and hypercapnic ventilatory reflexes in a dose-dependent manner. This effect might be more pronounced and prolonged in patients with COPD.
Halothane and nitrous oxide inhibit hypoxic pulmonary vasoconstriction (HPV) in a dose-dependant manner; newer inhalation anesthetics isoflurane, desflurane, and sevoflurane do not cause a significant depression in clinically relevant doses. None of the intravenous anesthetic agents interfere with the HPV response and intravenous anesthesia with propofol has been proposed as means of avoiding HPV modulation although research published in the last decade has been controversial.

Monitoring for LVRS should include:

Standard monitoring as recommended by the American Society of Anesthesiologists Standards for Intraoperative Monitoring
An indwelling arterial catheter for rapid-response hemodynamic monitoring and intermittent blood gas sampling and analysis. Because of the potential for hemodynamic instability on induction of general anesthesia, the intra-arterial blood pressure monitoring should be established prior to induction.
The routine use of pulmonary artery catheters is not supported by current literature.
Transesophageal echocardiography (TEE) may be employed in cases of intraoperative hemodynamic instability and provides pertinent information regarding left and right ventricular function.
Bispectral index of the electroencephalogram may be helpful to target an adequate depth of anesthesia
As patients with severe COPD may have increased sensitivity to neuromuscular blocking agents, the degree of neuromuscular blockade should be monitored

The choice of the anesthetic agent used for induction is mostly determined by the medical condition of the patient. Slow, careful titration of the anesthetic agents and vasoactive drugs during induction may provide better hemodynamic stability. Achievement of an adequate depth of anesthesia before laryngoscopy and intubation is paramount, as intubation in an inadequately anesthetized patient can lead to severe bronchospasm.

Lung isolation can be accomplished by any of the usual techniques double-lumen tube, single lumen tube with bronchial blocker or Univent tube; however double-lumen tubes tend to be the favored method for lung separation in LVRS by most practitioners.bronchial blockers are more prone to dislodgement and because of the small size of the central lumen provide slower deflation of the operative lung and do not permit suctioning of the operative lumen.

Intraoperative management of one-lung ventilation aims to: maintain adequate oxygenation, minimize intrinsic positive end-expiratory pressure (PEEP), minimize barotrauma and maintain adequate CO2 elimination.

A lung-protective ventilatory strategy will consist of small tidal volumes (TV) (5-7 ml/kg), peak inspiratory pressure below 35 cmH2O, inspiratory/ expiratory ratio between 1:3 to 1:5, and low respiratory rates and is aimed at preventing dynamic hyperinflation, minimizing the risk of disruption of suture lines or lung tissue and avoiding the intraoperative occurrence of pneumothorax or air leaks.
Although there is no unequivocal evidence that one mode of ventilation may be more beneficial than the other, pressure-controlled ventilation (PCV) may diminish the risk of barotrauma by limiting peak and plateau airway pressures. Also the decelerating flow pattern results in more homogenous distribution of the tidal volume and improved dead space ventilation. However, PCV in the presence of auto-PEEP may lead to unpredictible low TV and hypoventilation.
The application of external PEEP in patients with severe COPD has generally been discouraged due to the potential risk of barotrauma. Because of the heterogenous nature of auto-PEEP, patients with pre-existing auto-PEEP have an unpredictable response to application of external PEEP. The increase in total PEEP after application of external PEEP is not consistent and depends on the level of auto-PEEP.

Patients undergoing LVRS may benefit from a total intravenous anesthesia (TIVA) approach. Although current literature does not support a clear physiologic advantage of using one technique over another in patients with relatively normal lung function, avoiding modulation of HPV with TIVA may be clinically significant in patients with marginal lung function. More importantly though, patients with COPD undergoing LVRS have increased dead space therefore the uptake and distribution of the inhalational agents is unpredictable and the end-tidal volatile anesthetic concentration is inaccurate. Avoid the administration of long-acting systemic opioids; remifentanil may be a better choice when using TIVA.

Avoid hypothermia during the intraoperative period and with emergence. Besides its well known adverse effects (higher incidence of myocardial ischemia and wound infection, coagulopathy), hypothermia may result in shivering leading to an increased production of carbon dioxide and delayed extubation.

6. What is the author's preferred method of anesthesia technique and why?

What prophylactic antibiotics should be administered?

According to the Surgical Care Improvement Project (SCIP) guidelines patients should receive Cefazolin(1-2 gm), Cefuroxime (1.5 gm) or Cefamandole within 1 hour from incision. In case of β-lactam allergy Vancomycin (1-2 gm) or Clindamycin (300-900mg) should be used.

What do I need to know about the surgical technique to optimize my anesthetic care?

A variety of different approaches to LVRS have been proposed:

LVRS could be performed through median sternotomy, thoracosternotomy, standard thoracotomy and video-assisted thoracosopic surgery (VATS) technique. Most used approaches are median sternotomy and VATS. Most studies comparing median sternotomy and VATS have yielded conflicting results. The NETT showed that functional results as well as morbidity and mortality were comparable for LVRS by VATS or median sternotomy. The VATS approach, however, allowed earlier recovery at a lower cost than median sternotomy.
Both unilateral and bilateral approaches can be used, however bilateral VATS lung volume reduction is the preferred approach over unilateral approach. Multiple studies have shown that the bilateral procedure produces greater overall improvement than a unilateral procedure. Given the improvement associated with unilateral surgery, unilateral operation may still be offered in some patients who are not candidates for a bilateral operation due to prior thoracic intervention or inappropriate anatomy for bilateral lung volume reduction.
Methods for sealing the site of resected lung include the use of staples or laser (neodymium: yttrium-aluminum-garnet).
The position of the patient may vary. The patient may positioned supine with the arms supported above the head utilizing an ether screen or the patient may be positioned in lateral decubitus.

What can I do intraoperatively to assist the surgeon and optimize patient care?

Adequate lung isolation
Minimize mediatinal excursions in the surgical field by limiting TV applied to the non-operative lung while at the same time avoiding hypoventilation.
Communicate with the surgeon regarding the need for resuming two-lung ventilation when significant hypercapnia or hypoxemia occur.

What are the most common intraoperative complications and how can they be avoided/treated?

Tension pneumothorax. The abrupt development of cardiovascular collapse unresponsive to volume infusion and vasopressor administration and unexplained by auto-PEEP and/or malposition of the endotracheal tube should raise the suspicion of a pneumothorax. Due to positive pressure ventilation a pneumothorax becomes rapidly a tension pneumothorax and represents a true emergency. This complication needs immediate detection and treatment by aborting the surgical procedure, re-expanding the operative lung, and immediately inserting a chest tube in the contralateral chest
Tension pneumothorax: the abrupt development of cardiovascular collapse unresponsive to volume infusion and vasopressor administration and unexplained by auto-PEEP and/or malposition of the endotracheal tube should raise the suspicion of a pneumothorax. Due to positive pressure ventilation a pneumothorax becomes rapidly a tension pneumothorax and represents a true emergency. This complication needs immediate detection and treatment by aborting the surgical procedure, re-expanding the operative lung, and immediately inserting a chest tube in the contralateral chest.
Air trapping and dynamic hyperinflation resulting in decreased venous return is one of the most common causes of hypotension upon institution of positive pressure ventilation. If this is the etiology of hypotension, disconnecting the endotracheal tube from the breathing circuit and allowing the lung volumes to decrease will result in resolution of hypotension. An extreme form of air trapping and auto-PEEP can have a “tamponade” effect on the ventricular function. Such patients show a progressive increase in central venous pressures, pulmonary hypertension, and proportionally increased pulmonary capillary wedge pressures. That results in a low cardiac output state with progressive systemic hypotension and drastic reduction in oxygen delivery to tissues. If that condition is not recognized and corrected rapidly, the patient may expire.
Both tension pneumothorax and dynamic hyperinflation can be prevented by aggressively correcting airflow obstruction (confirming the correct position of the endotracheal tube, removal of secretions and inhaled bronchodilators). Optimizing the ventilatory parameters by increasing the expiratory time and decreasing the respiratory rate may allow more time for lung deflation.
Significant hypercapnic acidosis has numerous potential adverse effects such as increased intracranial pressure, decreased myocardial contractility, pulmonary hypertension, right heart failure, and cardiac arrhythmias. When significant acidosis develops (pH less than 7.2) maneuvers should be instituted to maximize minute ventilation, communication should be initiated with the surgeon and two-lung ventilation should be resumed whenever possible. In this clinical situation when carbon dioxide elimination is impaired, administration of sodium bicarbonate with the aim to normalize the pH value is not recommended as it might worsen the intracellular acidosis.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

Tracheal extubation immediately after surgery is an important aim after LVRS in order to minimize the risk of developing or exacerbating an air leak and avoid the deleterious hemodynamic effects of positive pressure ventilation.

Successful extubation however depends on multiple factors:

adequate pain control
complete reversal of neuromuscular blockade
absence of significant bronchospasm and secretions
absence of significant hypercapnia and acidosis
absence of respiratory depression due to residual anesthetic agents

With initiation of spontaneous breathing, the application of low level of extrinsic PEEP during weaning from mechanical ventilation might improve the lung mechanics and reduce work of breathing by shifting the effort from the patient to the ventilator.

Some investigators recommend changing the double-lumen tube to a single-lumen tube at the end of the procedure in order to facilitate “toilet” bronchoscopy at the end of the procedure and lower airflow resistance in the spontaneously breathing patient prior to extubation. The benefits of this maneuver have to be weighted against the risk of manipulating the airway taking into consideration the fact that when both lumens of the DLT are used the airflow resistance is only slightly higher compared to a single-lumen tube.

The patient should be placed in steep sitting position to facilitate diaphragmatic excursions, nebulized bronchodilators should be administered immediately after extubation, pain control should be optimized.

Extubation can be attempted even in the presence of moderate respiratory acidosis. Most patients demonstrate a pattern of recovery from the moderate hypercapnic acidosis within 1 or 2 hours following extubation.

c. Postoperative management

What analgesic modalities can I implement?

Adequate pain control is paramount in this high-risk group of patients. Inadequate pain control will result in splinting, poor respiratory effort, inability to cough and clear secretions leading to airway closure, atelectasis, shunting and hypoxemia. However, it is important to achieve pain control with minimal respiratory depression.

Thoracic epidural analgesia (TEA) with a continuous infusion of local anesthetics with or without narcotics is the favored modality of postoperative pain control after LVRS by most practitioners. There is evidence that TEA may provide a better quality of pain control than systemic opioids, may reduce the incidence of postoperative complications, may reduce the incidence of adverse cardiovascular events in the perioperative period and may improve gastrointestinal motility.

Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used as adjuvants in postoperative pain control. Potential adverse effects include decreased renal perfusion, inhibition of platelet aggregation, and predisposition to peptic ulcer disease and gastrointestinal bleeding.

Other potential techniques for pain control in LVRS patients include intrathecal morphine, intercostal nerve blockade, paravertebral nerve blockade, and pleural catheters. Paravertebral blockade provides comparable pain relief with epidural analgesia in thoracic surgery, has a better side-effect profile and is associated with a reduction in pulmonary complications. However, given the bilateral nature of the surgery, local anesthetic toxicity may be of concern as well as the possibility of developing pneumothorax/oneumothoraces, which could manifest after the institution of positive pressure ventilation and have extreme consequences.

What level bed acuity is appropriate?

Patients should be monitored in the immediate postoperative period in the an ICU setting. As postoperative respiratory failure and tracheal re-intubation carries with it significant morbidity, LVRS patients have to be monitored very closely after extubation and any deterioration in their respiratory status has to be treated very aggressively.

What are common postoperative complications, and ways to prevent and treat them?

Pulmonary complications are the most common type of complications after LVRS.

Pneumonia occurs in about 7 -14% of the patients
Respiratory failure requiring reintubation occurs in 5% to 10% of the patients and if postoperative reintubation occurs more than half of the patients will fail attempts to wean from the ventilator
Prolonged air leak is defined as an air leak that lasts at least 7 days following the procedure. This complication occurs in approximately 40% to 60% of patients and is associated with a more protacted and prolonged hospital stay. Risk factors for post-LVRS air leak include Caucasian race, lower FEV1 or diffusion capacity, use of inhaled steroids, upper-lobe predominant emphysema and presence of moderate to marked pleural adhesions.

Cardiac complications are the second most common cause of perioperative morbidity and mortality after lung resection surgery. Major cardiac morbidity, defined as intraoperative or postoperative arrhythmia requiring treatment, myocardial infarction or pulmonary embolus in the 30 days after lung volume reduction surgery, had an incidence of 20% in the NETT.

What's the Evidence?

Macnee, W. “Pathogenesis of chronic obstructive pulmonary disease”. Clin Chest Med . vol. 28. 2007. pp. 479-513.

Hartigan, PM, Pedoto, A. “Anesthetic considerations for lung volume reduction surgery and lung transplantation”. Thorac Surg Clin . vol. 15. 2005. pp. 143-57.

Fishman, A, Martinez, F, Naunheim, K. “A randomized trial comparing lung-volume-reduction surgery with medical therapy for severe emphysema”. N Engl J Med . vol. 348. 2003. pp. 2059-73.

Tschernko, EM. “Anesthesia considerations for lung volume reduction surgery”. Anesthesiol Clin North America. vol. 19. 2001. pp. 591-609.

Edwards, MA, Hazelrigg, S, Naunheim, KS. “The National Emphysema Treatment Trial: summary and update”. Thorac Surg Clin. vol. 19. 2009. pp. 169-85.

Lohser, J. “Evidence-based management of one-lung ventilation”. Anesthesiol Clin. vol. 26. 2008. pp. 241-72.

Block, BM, Liu, SS, Rowlingson, AJ, Cowan, AR, Cowan, JA, Wu, CL. “Efficacy of postoperative epidural analgesia: a meta-analysis”. JAMA. vol. 290. 2003. pp. 2455-63.

Koehler, RP, Keenan, RJ. “Management of postthoracotomy pain: acute and chronic”. Thorac Surg Clin. 2006.

Slinger, PD, Hichey, DR. “The interaction between applied PEEP and auto-PEEP during one-lung ventilation”. J Cardiothorac Vasc Anesth. vol. 12. 1998. pp. 133-6.

DeCamp, MM, Blackstone, EH, Nauheim, KS. “Patient and surgical factors influencing air leak after lung volume reduction surgery: lessons learned from the National Emphysema Treatment Trial”. Ann Thorac Surg. vol. 82. 2006. pp. 197-206.

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