Chapter 10
Thoracic surgical complications
Martin Chamberlain
1 | Which cardiac arrhythmias occur following thoracic surgery? |
• | Atrial fibrillation and atrial flutter are the most common, occurring in 10-15% of patients following a lobectomy and in up to 40% following a pneumonectomy. |
• | They usually occur on the 1st-3rd postoperative day and are equally common following open or video-assisted thoracoscopic surgery (VATS). |
• | Atrial fibrillation and flutter are associated with increased morbidity and postoperative length of stay. |
• | The precise aetiology of cardiac arrhythmias following thoracic surgery is unknown but certain pre-operative and intra-operative factors can contribute to their development (Table 1). |
2 | What are the principles of managing a patient with a postoperative cardiac arrhythmia? |
• | The treatment depends on obtaining a precise diagnosis and the degree of associated haemodynamic compromise. |
The aim is to control the ventricular rate, and return to and maintain sinus rhythm. | |
• | Electrolyte disturbance, acid-base imbalance and hypoxia should be corrected. |
• | If the above measures fail, pharmacological therapy with anti-arrhythmic medication should be instigated, with digoxin used as first-line therapy. |
• | DC cardioversion should be employed if the patient is acutely compromised. |
• | A cardiology opinion may also be required in certain patients. |
• | There is no evidence that pre-operative anti-arrhythmic therapy is beneficial in reducing the incidence of postoperative atrial fibrillation. |
• | Anticoagulation may be necessary if sinus rhythm is not restored. |
3 | What is postoperative atelectasis (Figure 1)? |
• | Atelectasis represents collapse of a pulmonary segment or lobe, resulting in a V/Q mismatch and hypoxia. |
• | It is the most common postoperative complication following lung resection and usually occurs 24-48 hours postoperatively in up to 40% of patients, with 5-10% being clinically significant. |
• | Certain patients have an increased risk of developing postoperative atelectasis, including those with: |
a) | an inability to cough; |
b) | sputum retention; |
c) | hypoventilation due to pain, sedation and diaphragmatic splinting; |
d) | a pleural effusion, resulting in compression of the underlying lung. |
• | Chest radiological (CXR) features of atelectasis include: |
a) | displacement of the hilum; |
b) | mediastinal shift towards the side of the collapse; |
c) | volume loss of the ipsilateral hemithorax; |
d) | elevation of the ipsilateral diaphragm; |
e) | crowding of the ribs; |
f) | compensatory hyperlucency of the remaining ipsilateral lobes; |
g) | silhouetting of the diaphragm or the heart border. |
4 | What are the principles of managing a patient with atelectasis? |
• | Prevention is the mainstay. |
• | Non-invasive techniques: |
a) | regular postoperative physiotherapy; |
b) | early mobilisation; |
c) | encourage the patient to sit out of bed; |
d) | incentive spirometry; |
e) | breathing exercises; |
f) | nebulisers; |
g) | humidified oxygen. |
• | Invasive techniques: |
a) | nasotracheal suction; |
b) | continuous positive airway pressure (CPAP); |
c) | flexible bronchoscopy; |
d) | mini-tracheostomy. |
What is the aetiology of postoperative respiratory failure? | |
• | Respiratory failure can be caused by a wide spectrum of underlying pathologies, often in combination, including: |
a) | narcotic overdose or inadequate reversal; |
b) | bronchospasm; |
c) | atelectasis; |
d) | pneumonia; |
e) | pulmonary oedema, secondary to fluid overload or heart failure; |
f) | pre-existent poor underlying lung function (minimal reserve); |
g) | pulmonary embolism; |
h) | acute respiratory distress syndrome (ARDS). |
• | Respiratory failure can be subclassified as: |
a) | Type I – hypoxic (hypoxaemia); |
b) | Type II – ventilatory (primarily hypercapnia); |
c) | Mixed – combination of hypoxaemia and hypercapnia. |
• | Respiratory failure is the main cause of mortality following thoracic surgery and occurs in 2% of patients, with a 50-100% mortality. |
6 | What are the principles of management in a patient with postoperative respiratory failure? |
• | Supplemental oxygen by mask or CPAP. |
• | Naloxone for patients with inadequate opioid reversal. |
• | Diuretics for patients with pulmonary oedema. |
• | Broad-spectrum antibiotics. |
• | Anticoagulation for patients with a pulmonary embolus. |
• | Nebulisers for patients with bronchospasm. |
• | Flexible bronchoscopy and suctioning for patients with sputum retention and atelectasis. |
• | Despite the above supportive measures, some patients will also require endotracheal intubation and mechanical ventilatory support. |
7 | What is acute respiratory distress syndrome (Figure 2)? |
• | Acute respiratory distress syndrome (ARDS) is a very severe form of acute lung injury (ALI) and is defined as an acute condition characterised by bilateral pulmonary infiltrates and severe hypoxia in the absence cardiogenic pulmonary oedema. |
• | The pathogenesis of ARDS includes: |
raised pulmonary capillary pressure; | |
b) | reduced lymphatic drainage; |
c) | endothelial damage; |
d) | lung hyperinflation; |
e) | single-lung ventilation intra-operatively. |
• | ARDS is characterised by increased alveolar-capillary permeability, resulting in an excessive influx of fluid into the alveolar spaces. |
• | It usually presents 2-3 days following an uncomplicated postoperative recovery with dyspnoea and hypoxia. |
• | ARDS is rapid in its progression and more common following a pneumonectomy (5%) compared to a lobectomy (2%). |
• | The radiological features of ARDS include widespread bilateral pulmonary infiltrates. |
• | Most patients are treated with mechanical ventilation and the mortality rate is high (>75%). |
8 | What are the characteristic features of postoperative pulmonary oedema? |
• | Pulmonary oedema is defined as an accumulation of fluid in the alveoli and lung parenchyma, resulting in impaired gas exchange. |
Postoperative pulmonary oedema can be caused by: | |
a) | excessive peri-operative fluid administration – which may have been used to treat hypotension, intra-operative fluid loss, the hypotensive effect of epidural analgesia or oliguria; |
b) | underlying congestive heart failure; |
c) | right ventricular dysfunction immediately following a pneumonectomy; |
d) | rapid re-expansion of a collapsed lung (Figure 3). |
9 | What are the characteristic features of postoperative pneumonia (Figure 4)? |
• | Postoperative pneumonia represents a nosocomial infection of the lower respiratory tract. |
• | It is usually caused by bacterial organisms, which originate from the oral cavity, pharynx and hypopharynx, including: |
a) | Staphylococcus aureus; |
b) | Streptococcus pneumoniae; |
Haemophilus influenzae; | |
d) | Pseudomonas aeruginosa; |
e) | Klebsiella spp; |
f) | Escherichia coli; |
g) | Acinetobacter spp. |
• | The development of postoperative pneumonia is associated with sputum retention and atelectasis. |
• | The CXR usually demonstrates an area of patchy consolidation. |
• | Postoperative pneumonia is treated with: |
a) | antibiotic therapy (appropriate to the underlying organism); |
b) | supplemental oxygen (if required); |
c) | chest physiotherapy. |