Thoracic anaesthesia. Simon May

Transcription

1 Thoracic anaesthesia Simon May

2 Contents Indications for lung isolation Ways of isolating lungs Placing a DLT Hypoxia on OLV Suitability for surgery Analgesia Key procedures

3 Indications for lung isolation

4 Indications for lung isolation Preventing cross contamination of the other lung from blood, infection and lavage. Controlling distribution of infection, i.e. bronchopulmonary fistula. Facilitating surgery, i.e. lobectomy, pneumonectomy, pleurectomy, decortication, bullectomy, diaphragmatic hernia repair and oesophagectomy.

5 How can you isolate the lungs?

6 How can you isolate a lung? Double lumen endobronchial tubes. Modern day tube based on Robertshaw design. 41 of 39Ch gauge for men, 37Ch for females 39Ch has lumen diameter of 6mm, 35Ch 4.5mm 29cm for height 1.7m, 1cm further for every 10cm in height. (Carlen s (L) and White s (R) used previously but many more variations) Endobronchial blockers (normal ETT tube placed too far)

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8 Placing a double lumen tube

9 Placing a double lumen tube Assess risks vs benefits of DLT. History, examination and investigation of airway Normal IV induction and relaxant. With stylet in tube. Concavity of tube facing 12 O clock. Place into trachea. Once tip in trachea, withdraw stylet and rotate 90 degrees to whichever side of tube you are using. Slide down until resistance is felt. Inflate only trachea cuff. Initiate ventilation and confirm ETCO2 and bilateral air entry. Inflate bronchial lumen. Clamp trachea line and open to air. Check airway pressure and assess if lung sounds only on isolated lung side. Examine placement of tube with bronchoscope. Check for cuff herniation. Check for placement too far. If right sided tube check RUL ventilation. (Reassess whenever patient is moved. Few mm can make huge difference)

10 Where can it go?

11 Why do patient s become hypoxic on OLV?

12 Why do patients become hypoxic on OLV? Placed in lateral decubitus position, with ventilated lung being the dependant lung. Hypoxaemia is induced by following issues: Oxygen storage, oxygenation and ventilation defect Dissociation of oxygen from haemoglobin V/Q relationships Hypoxic pulmonary vasoconstriction

13 Management of hypoxia

14 Management of hypoxia on OLV Alert surgeon Increase FiO2 to 1.0 Quick check of anaesthetic machine, ventilator and tubing. Switch to manual ventilation and assess compliance or for signs of inadequate paralysis Check for dislodgement of double lumen tube via bronchoscope, assess for secretions. PEEP to ventilated lung (may exacerbate condition) Oxygen insufflation to non-ventilated lung or CPAP If pulmonary artery clamp to be used intra op, can this be done sooner? Optimise cardiac output and Hb Return to dual lung ventilation (Assess for signs of bronchospasm, pneumothorax etc) (consider HFJV or inhaled nitric oxide)

15 Suitability for lung resection surgery

16 Anatomy of BPT

17 Assessing thoracic patients

18 Assessing thoracic patients Need to also assess cardiac risk. Usually with RCRI. Age. Over 80 then high risk but lobectomy and wedge can be done. Less than 80 age is not predominant factor but co-morbidity is. Assess nutrition. Weight loss of >10% is high risk. WHO performance status 2 or worse are high risk

19 WHO performance scale

20 Analgesia for thoracotomy

21 Analgesia for thoracotomy One of the most painful procedures Aggravated by breathing, physiotherapy and vomiting. Poor pain relief equals, atelectasis, infection, poor cough, secretion retention and poor mobilisation Poor pain relief increases sympathetic tone and myocardial strain Poor pain relief associated with chronic neurogenic pain Poor pain relief increases ICU and hospital admission length and increases mortality.

22 Innervation of pain C and A delta fibres transmit pain Intercostal nerves supply skin and intercostal muscles Lung and mediastinum is carried by Vagus nerve (Visceral pleura is insensitive) Parietal pleura (very sensitive) from intercostal nerves and phrenic nerve Also, pain from positioning in lateral decubitus (i.e. shoulder)

23 Pain relief options PCA or IV opioid infusions. Need adequate loading. Epidural. Continuous infusion, PCEA or combination of both (considered gold standard). Pros vs Cons. Intrathecal opioid (particularly Morphine). Paravertebral block, intercostal nerve block, inter pleural analgesia and cryoprobe neurolysis. NSAIDs, paracetamol etc.

24 Recent BJA article

25 Key thoracic procedures

26 Key thoracic procedures Rigid bronchoscopy and stent insertion Mediastinsocopy Wedge resection, lobectomy and pneumonectomy Thoracoscopy / VATS Bullectomy and lung volume reducing surgery Decortication Broncho-pleural fistula Pleurectomy Thoracic sympathectomy (Oesophagectomy) (Chest injury: Bronchial, oesophagus, diaphragm) (make sure you understand the principles of jet ventilation)

27 Questions