How dangerous is thoracic surgery?

With the advances in diagnostic imaging and surgical techniques for lung diseases and cancers, more patients are presenting for thoracic surgery. Often patients are old with multiple comorbidities, which predispose them to be significant and life-threatening complications. The decision to operate on these patients requires careful assessment and planning by the multidisciplinary thoracic team. In this review we aim to present the preoperative evaluation and investigations, the current risk scoring systems in place and the optimisation of these patients in an attempt to lower the risk and to allow informed decision making surrounding their appropriate treatment. We also discuss specific high-risk procedures and interventions which may be utilised in specialist centres to enable surgery to take place in unique situations and complex patients.

 

Thoracic surgical patients often have multiple comorbidities due to the close association between lung cancer, smoking, emphysema and cardiovascular disease. These often predispose them to numerous potentially significant complications. The decision to operate on these patients requires careful assessment of the potential risks and benefits. This is usually undertaken as part of a multidisciplinary decision between the patient, respiratory physician, thoracic surgeon and anaesthetist and will endeavour to take into account the extent of the surgery, the surgical approach and comorbid condition.

 

Despite significant improvements in mortality and morbidity following lung resection over recent years, the risk is not insignificant. In a recent analysis from the European Society of Thoracic Surgeons (ESTS) database looking at almost 48,000 patients, the average 30-day mortality was 2.7%, and morbidity was 18.4% . The extent of the surgery was found to be a contributing factor, with pneumonectomy carrying increased mortality at 6.8%, lobectomy at 2.3% and segmentectomy at 1.4%. The most frequent cause of death following lung resection surgery is acute lung injury and acute respiratory distress syndrome, followed by bronchopleural fistula and empyema, cardiac events and cerebrovascular accidents.

 

Common complications after thoracic surgery include atelectasis, haemorrhage, pulmonary oedema, atrial fibrillation, wound infection, pneumonia, persistent air leak, and respiratory failure. Other, less frequent complications include bronchopleural fistula, empyema, cardiac herniation, pulmonary torsion, chylothorax, thromboembolism, right ventricular failure, and neurological injury. Thoracic surgical patients are frequently elderly, have substantial concurrent disease, and are particularly prone to respiratory complications. About 20% of patients undergoing lung resection suffer one or more complications after surgery, and about 2% die. These risks are doubled following pneumonectomy and are far less common after limited wedge resection. Risk factors include patient age, current smoking, underlying carcinoma, and chronic lung disease. Anaesthetic and surgical techniques that assist early awakening and adequate pain control will promote restoration of respiratory function, and this should lead to an uneventful postoperative course.

 

Risk scoring system for thoracic surgery patients has not been widely used, as of recently. We tried to forge a risk scoring system that predicts the risk of postoperative complications in patients undergoing major thoracic surgery. We used a prolonged ICU stay as a representative of postoperative complications and tested various possible risk factors for its relation.

 

Data from all patients who underwent significant lung and esophageal cancer surgeries, between 2005 and 2007 in our hospital, were collected retrospectively (n = 858). Multiple logistic regression analysis was performed with various possible risk factors to build the risk scoring system for prolonged ICU stay (> 3 days).

 

A large portion of patients undergoing thoracic surgery develops postoperative complications. Major respiratory complications occur in 20%, and cardiac complications occur in 15% of the thoracic population . If we know the risk of postoperative complications of an individual patient, based on an objective scoring system, we can obtain better patient’s consent on their anesthetic and surgical risks, and focus our attention and resources on higher-risk patients.

 

Cardiac surgeons have led the field of risk stratification. and Euro-SCORE system has been used widely to predict outcomes in adult patients undergoing cardiac surgery. However, producing a risk prediction formula for thoracic surgeries has been more difficult. Procedures are less standardised than cardiac surgeries. Lung resection inevitably results in a patient’s physiologic deficit, unlike patients undergoing cardiac surgery who generally do not suffer a postoperative physiologic deficit. This deficit is variable, according to the extent of lung resection, and the pre-existing lung function of the patient. Some patients receive preoperative chemotherapy and radiotherapy. Therefore, there have not been widely used risk scoring systems for thoracic surgery yet.

 

In this study, we tried to develop a risk scoring system for postoperative complications in thoracic surgical patients from the data between 2005 and 2007 in our hospital. We focused on prolonged ICU stay as the representative of postoperative complications because there exists a wide range of postoperative complications. Still, significant ones eventually lead to an extended ICU stay. Usual patients return to the general ward on the following day or two. Thus, we regarded more than three days of ICU stay as prolonged ICU stay. We evaluated various possible risk factors concerning extended ICU stay and developed a risk scoring system by multiple logistic regression analysis.

 

We hope this study provides a stepping stone to developing a widely used risk scoring system in the field of thoracic surgery. Thoracic surgery refers to operations on organs in the chest, including the heart, lungs and esophagus. Examples of thoracic surgery include coronary artery bypass surgery, heart transplant, lung transplant and removal of parts of the lung affected by cancer. Specialised thoracic surgeons treat lung and esophageal cancer, while specialised cardiac surgeons treat the heart.

 

Thoracic surgery, also known as chest surgery, may be used to diagnose or repair lungs affected by cancer, trauma or pulmonary disease. For lung cancer, your surgeon may remove nodules, tumours and lymph nodes to diagnose, stage and treat the condition.

 

Thoracic surgery procedures may be performed with either minimally invasive techniques or an open surgical procedure called a thoracotomy. Your surgeon may opt for a thoracotomy when it is necessary to see large portions of the lung or inner chest cavity. The process may be performed to remove the entire lung or a part of the lung.

 

THE pain that accompanies thoracic surgery is notable for its intensity and duration. Acutely, moderate to severe levels of anxiety may not decrease substantially throughout hospitalisation and the first postoperative month.Chronically, grief can last for months to years, and even low levels of anxiety can decrease function. Other than pain syndromes associated with limb amputation, pain after thoracic surgery may be the most recognised pain syndrome associated with a specific operation. Although used with increasing frequency, thoracoscopic approaches have not had a favourable impact on the pain that many had anticipated.Given that the adverse effects of thoracic surgery on pulmonary function can be mitigated by adequate perioperative analgesia, it is not surprising that thoracic surgeons have joined anesthesiologists in becoming strong advocates of analgesic interventions known to limit the pain accompanying thoracic surgery. Here, we review evidence-based strategies for preventing and treating this type of pain.

 

Preoperative optimisation of specific risk factors

The outcome of surgical procedures is not measured only by clinical endpoints but also shorter stays and lower costs . Patients’ discharge is delayed commonly due to inadequate pain relief, infection, arrhythmias, prolonged air leak and debility . Many complications that occur from thoracic operations can be anticipated. An aggressive preoperative work up mitigates morbidity and shortens convalescence.

 

A preoperative evaluation can provide a suitable and safe postoperative prediction of complications in patients submitted to lung resection. Patients with COPD, hypoxemic, older, and anemic patients must be classified as high-risk for developing these complications.

 

Minimally invasive thoracic surgery is a way of performing surgery in the chest through small incisions, without making significant cuts or incisions in the body. It does not require spreading apart of the ribs. Surgeons use a camera and instruments to get to the lung through small incisions in between the bones. There are two different options available for minimally invasive thoracic surgery; video-assisted thoracoscopic surgery (VATS) and robotic-assisted surgery.

 

Video-assisted thoracoscopic surgery (VATS) is a procedure in which a small tube called a thoracoscope is inserted through a small incision between the ribs. At the end of the tunnel is a small camera. This lets the surgeon see the entire chest cavity without having to open up the chest or spread the ribs. The surgeon then removes lung tissue with specially designed instruments inserted through one or two additional small incisions.

 

In robotic-assisted surgery, a surgeon will sit at a console next to the patient in the operating room and control the instruments, including a camera, on the robotic surgical system. A small 3D high definition camera is placed through one of the small incisions to provide a good view of the inside of the chest cavity. At the same time, wristed robotic instruments are inserted through the other tiny incisions made in between the ribs. The surgeon removes lung tissue through one of the small incisions. The use of the wristed instruments lets the surgeon perform the surgery without having to make larger incisions to open up the chest or spread the ribs.

 

Video-assisted Thoracoscopic procedures are done with increasing frequency for many indications. The incidence of postoperative complications is 9% after VATS, and they include haemorrhage, empyema, air leak, pneumonia and surgical emphysema  commonly. Still, most of the complications which happen in thoracotomy could potentially occur with video-assisted Thoracoscopic procedures.

 

Most importantly, the incidence of postoperative pain is much less in VATS than open procedures, and they have a shorter hospital stay. The proponents of VATS have published many series about the feasibility, lesser complication rate, reduced pain, early mobility and discharge. Some groups did not find any statistical benefit in performing VATS and have quoted a higher bleeding and intraoperative complication rate . In our unit, we perform VATS for all kinds of thoracic procedures if patients are suitable for it. VATS lobectomy is a safe procedure, which reduces perioperative pain and improves postoperative physical status. The results obtained with early-stage lung cancer are excellent and may reflect inherent oncologic advantageous consequent upon reduced operative trauma. Detection of early-stage lung cancer is potentially rewarding and will become a practical imperative if survival results are to be improved. Thus the scope for VATS resection may increase significantly. In our view, VATS lobectomy is the procedure of choice for early-stage lung cancer and multicentre prospective randomised trials comparing this therapy against conventional open resection are overdue.

 

What to Expect

  • Your surgery will begin with you being placed under general anesthesia.
  • Once you are asleep, a breathing tube is placed into your airway to allow each lung to be separately inflated during surgery.
  • You are then positioned on your side.
  • The surgeon then makes one to five small incisions, each about an inch wide, in between your ribs. The surgeon inserts the camera and VATS or wristed robotic instruments between the bones.
  • At the end of the surgery, the surgeon will insert a chest tube through one of the small incisions to drain extra fluid or air leaking into the chest and help your lungs to re-inflate. This tube remains in place for a few days and is typically removed at the bedside before you go home.
  • Recovery time is generally shorter after minimally invasive surgery compared to open surgery, but you will still need time to rest and recover. Once home, most patients will regain most of their strength, energy and breathing after two to three weeks.

 

Risk scoring during thoracic surgery

 

There are several specific high-risk procedures and interventions that we will discuss in more detail. The methods discussed below, however, are highly specialised and require meticulous perioperative planning involving several different specialist groups. They should be reserved for the experienced multidisciplinary thoracic team.

 

The resection of tracheobronchial lesions poses a great surgical and anaesthetic challenge . The insult to the integrity of the airway requires the anaesthetist to secure the remaining bronchial segments with cross-field ventilation to achieve sufficient and adequate oxygenation. Whether this is achieved by jet ventilation or instrumentation and securing of the airway across the surgical field, it brings additional difficulty with surgical access and reduced visibility. Both techniques offer a narrow margin of safety and challenge in further manipulation of the airway in the case of unexpected endobronchial tube displacement, tube cuff leakage or ineffective ventilation during one-lung ventilation.

 

To address these difficulties and to ensure adequate oxygenation and haemodynamic stability, the use of extra-circulatory support such as veno-arterial extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB) has been used. However, these techniques require some degree of anticoagulation and introduce the risk of tumoral cells spreading within the CPB circuit. This, together with the complications associated with arterial cannulation, can out-weigh the benefit when compared with conventional or cross-field airway management.

 

Alternatively, experience with venovenous ECMO (VV-ECMO) for critically ill patients increased exponentially after the N1H1 epidemic in 2009 . The development of low-resistance and heparin-coated poly methyl pentene gas exchange circuits, and the use of percutaneous peripheral venous cannulation (i.e., femoral vein to jugular vein or femoral vein to femoral vein) makes VV-ECMO the extracorporeal life support of choice for complex thoracic surgery. To avoid anticoagulation, the drainage and return cannula can be flushed with normal saline until the ECMO pump achieves maximum flow (i.e., between 3.5–4 litres/min). For the majority of patients, the ECMO flow is enough to provide adequate oxygenation, and the mechanical ventilation can be stopped completely to facilitate the tracheobronchial resection. Larger patients, however, may require partial ventilation of the remaining lung parenchyma. Redwan et al. reported a case series of eight patients with maximum apneic oxygenation of 45 min with average carbon dioxide concentration.

 

In our Centre, we perform tracheal resections and repairs with the support of VV-ECMO. In one case, an apnoeic period of more than four h was achieved, until the anastomosis was complete and the patient was allowed to recover spontaneously ventilating through a supraglottic airway device. This enabled avoidance of any potentially harmful positive pressure ventilation after the tracheal reconstruction.



Risk factors for postoperative complications 

 

The postoperative rate of complications was 52.9%: respiratory (34.3%), infectious (31%), and cardiovascular (21.4%). Respiratory complications were related to smoking (p < 0.01, RR 2.31), airway obstruction by spirometry (p = 0.01, RR 2.60), presence of anemia (p < 0.01, RR 2.13), and prolonged prothrombin time [PT] (p = 0.03, RR 1.77). Infection complications were related to smoking (p < 0.01, RR 2.69), airway obstruction by spirometry (p = 0.01, RR 3.31), presence of anemia (p < 0.01, RR 2.10), and prolonged PT (p = 0.03, RR 2.29). Cardiovascular problems were related with older age (p < 0.01, RR 2.66), cigarette smoking (p < 0.01, RR 4.55), and hypoxemia (p = 0.03, RR 2.43). The postoperative mortality rate was 7.1%.

 

Pain management is of paramount importance postoperatively as patients need to comply for chest physiotherapy and ambulation, and they will be unable to do so if they have severe pain. There are various ways by which pain is managed. They include epidural catheters preoperatively, paravertebral methods pre or intraoperatively or intravenous patient-controlled analgesia. On withdrawing these agents patients will need oral analgesics for the duration of time till they are pain-free. These include paracetamol, NSAID and narcotic agents.

 

The initial concern that thoracic epidural catheter insertion would lead to more frequent complications has not been borne out. Upper thoracic epidural catheter placement may be associated with fewer serious complications than lower thoracic or lumbar epidural placement.The reason for this probably resides in the increased distance from nerve roots involved in lower extremity, bowel, and bladder function. The potentially catastrophic complications of epidural or intraspinal hematoma are best prevented by the realisation that motor blockade should not occur with dilute local anesthetic solutions, and postoperative motor weakness should trigger immediate imaging studies and neurosurgical consultation. Clearly, concerns about coagulopathy can limit epidural catheter placement.

 

The concern about pneumothorax with the performance of ICNBs is prevented in the case of thoracic surgery because a chest tube is generally placed. However, the total dose of local anesthetic should be carefully calculated, because ICNBs are notable for high systemic blood levels from rapid absorption of local anesthetic. The issues related to paravertebral blocks are similar to those of ICNBs and also include hypotension from sympathectomy in some patients because of the proximity of the paravertebral space to the neuraxis.

 

Noxious input associated with thoracic surgery is conveyed to the central nervous system along the intercostal, vagus, and phrenic nerves. Afferent phrenic activity is believed to be the source of the shoulder pain that frequently accompanies thoracic procedures because phrenic8 curtails this but not suprascapular or epidural blockade.Intercostal nerve dysfunction resulting from the incision, retraction, trocar placement, or suture is common and likely plays a significant role in the pain accompanying thoracic surgery. Besides, the need for constant respiratory effort and enhanced pulmonary toilet produces an intense and relentless barrage of noxious input to the central nervous system.

 

Initial reports indicated that 50% of patients describe pain 1 yr after thoracotomy, with many continuing to report pain even years later.Fortunately, the prevalence of post-thoracotomy pain may be modifiable, with rates as low as 21% one year after surgery when perioperative pain is managed aggressively.Surprisingly, video-assisted thoracic surgery (VATS) is associated with a prevalence of chronic pain comparable to that of open procedures,with rates of illness ranging from 22%to 63%, four which is probably due to intercostal nerve and muscle damage from trocar insertion. In contrast, residual pain 1 yr after surgery is reported to be 25% after median sternotomy,emphasising the role that reduced intercostal nerve disruption and improved stability of the closure may play in reducing chronic pain. Several demographic and clinical factors help to identify patients predisposed to the development of chronic postsurgical pain. These include anxiety, depression, previous surgery, concurrent pain, lesions of the chest wall, youth, female sex, and increased levels of pain and analgesic use in the perioperative period.

 

Lung volumes after thoracic surgery may be reduced by up to 50%, and aggressive analgesic therapy leads to improvements in pulmonary function not observed with standard treatment .Supraventricular tachydysrhythmias are commonly seen after thoracic surgery. They may be less likely in conjunction with specific thoracic epidural analgesia regimens, although this is more likely due to modification of sympathetic outflow than the associated analgesia. When pain persists, physical activity is reduced and even low levels of anxiety have been associated with the reduced physical and social event as well as global perceptions of decreased health.

 

Conclusion 

With improvements in surgical techniques and anaesthetic management, the definition of high-risk in thoracic surgery is something of a moving target. There are several risk scoring systems in place which use several objective criteria to help with preoperative decision making with regards to suitability for a surgical treatment. These scoring techniques, however, fail to incorporate subjective criteria such as the individual patient’s ability, motivation and expectations, the healing ability and the anaesthetic techniques. It is also clear from the literature that there is no agreed consensus on the definition of “high-risk” and what this means in terms of outcome.

 

Surgical resection is the gold-standard treatment for early lung cancer, and the decision to operate depends on some variables including careful assessment of the potential risks and benefits which will be derived from series and trials in the literature, scoring systems, registry data and the personal experience of the team. It should involve a multidisciplinary approach, including shared decision-making with the patient.

 

New techniques and advances mean that we can operate safely on the “high-risk” patient with multiple comorbidities. But this should involve an experienced and dedicated thoracic service with experienced surgeons and anaesthetists, specialised high-dependency units and ward facilities, and thoracic surgery support staff including nurses, physiotherapists, education teams, and involvement of specialised services (e.g., cardiology, PH team, ECMO) where required. High-risk thoracic surgery requires a truly individualised patient-centred and multidisciplinary approach.

 

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