ANESTHESIA FOR CHRONIC LUNG DISEASE

Preoperative assessmentIntraoperative management

MonitoringLung isolation techniquesPositioningOne lung Ventilation

Postoperative managementPostoperative analgesiaComplications

Preoperative Assessment

AimIdentify patients at high risk Use that risk assessment to stratify

perioperative management and focus resources on the high-risk patients to improve their outcome.

Assessment of Respiratory function

Detailed historyBaseline SpirometryRespiratory MechanicsLung parenchymal functionCardiopulmonary interaction

Respiratory mechanics

For example, after a right lower lobectomy a patient with a preoperative FEV1 (or DLCO) 70% of normal would be expected to have a postoperative

FEV1 = 70% × (1 - 29/100) = 50%

ppoFEV1% = preop FEV1% × (1- %Functional lung tissue removed/100)

Slinger PD, Johnston MR: Preoperative assessment: an anesthesiologist's perspective. Thorac Surg Clin 15:11, 2005.

Ppo FEV1 >40% -Low risk 30-40%- mod risk < 30% - high risk

Cardiopulmonary InteractionMaximum oxygen consumption (Vo2max)

Most useful predictor of post-thoracotomy outcome. Morbidity and mortality is unacceptably high- Vo2max <15 mL/kg/min.Few patients with a Vo2max >20 mL/kg/min have respiratory

complications

Stair climbing5 flights - Vo2max >20 mL/kg/min2 flights - Vo2max of 12 mL/kg/min

6-minute test (6MWT)<2000 ft (610 m) - Vo2max <15 mL/kg/min Patients with a decrease of Spo2 greater than 4% during exercise are at

increased risk for morbidity and mortality.

Preoperative Optimization• Stop smoking, avoid industrial

pollutants • Dilate airways• Loosen secretions

– Airway hydration (humidifier/nebulizer)

– Systemic hydration– Mucolytic and expectorant drugs

• Remove secretions– Postural drainage– Coughing– Chest physiotherapy (percussion

and vibration)

• Adjunct medication– Antibiotics—if purulent

sputum/bronchitis– Antacids, H2 blockers, or PPIs—if

symptomatic reflux.

• Increased education, motivation, and facilitation of postoperative care– Psychological preparation– Preoperative pulmonary care

training• Incentive spirometry• Secretion removal maneuvers

– Preoperative exercise– Weight loss/gain– Stabilize other medical problems

Summary of initial preoperative assessment

All patients: Assess exercise tolerance estimate predicted

postoperative FEV1% discuss postoperative

analgesia discontinue smoking

Patients with predicted postoperative FEV1< 40%: DlCO Ventilation perfusion Scan VO2 max   

Cancer patients: consider the “4 Ms”:

mass effects metabolic effects Metastases medications   

COPD patients: Arterial blood gas analysis Physiotherapy bronchodilators   

Increased renal risk: Measure creatinine and blood

urea nitrogen

Intraoperative Monitoring

• Oxygenation• Capnometry• Arterial blood pressure• CVP• Pulmonary artery pressure• Fibreoptic bronchoscopy• Urine output• Temperature

Lung Isolation Techniques

• Double lumen tube• Bronchial blocker– Arndt – Cohen– Fuji

• Univent tube• Endobronchial tube• Endotracheal tube advanced into bronchus

Double lumen tube Carlens tube Robertshaw tube

Advantages Quickest to place successfully Repositioning rarely required Bronchoscopy to isolated lung Suction to isolated lung CPAP easily added Can alternate OLV to either lung

easily Placement still possible if

bronchoscopy not available

Disadvantages Size selection more difficult Difficult to place in patients

with difficult airways or abnormal tracheas

Not optimal for postoperative ventilation

Potential laryngeal trauma Potential bronchial trauma

Lateral decubitus position for thoracotomy

Positioning• Position Change–W/f hypotension– Secure all lines and monitors –Make an initial “head-to-toe” survey – Check oxygenation, ventilation,

hemodynamics, lines, monitors, and potential nerve injuries.

– Reassess after repositioning– Recheck Endobronchial tube/blocker position

and the adequacy of ventilation by auscultation and fiberoptic bronchoscopy after repositioning.

“Head-to-Toe” Survey • Dependent eye  • Dependent ear pinna  • Cervical spine in line with thoracic spine• Dependent arm:   – Brachial plexus– Circulation  

• Nondependent arm:   – Brachial plexus– Circulation  

• Dependent and nondependent suprascapular nerves  • Nondependent leg: sciatic nerve  • Dependent leg:– Peroneal nerve  – Circulation

Treatment of Hypoxemia• Severe or precipitous desaturation:

– Resume two-lung ventilation (if possible).• Gradual desaturation:  

– Ensure that delivered FIO2 is 1.0– Check position of DLT or blocker with fiberoptic bronchoscopy– Ensure cardiac output is optimal; decrease volatile anesthetics to < 1

MAC– Apply a recruitment maneuver to the ventilated lung – Apply PEEP 5 cm H2O to the ventilated lung – Apply CPAP 1-2 cm H2O to the nonventilated lung (apply a – recruitment maneuver to this lung immediately before CPAP)– Intermittent reinflation of the nonventilated lung  – Partial ventilation techniques of the nonventilated lung:

• Oxygen insufflation • High-frequency ventilation  • Lobar collapse (using a bronchial blocker)

– Mechanical restriction of the blood flow to the nonventilated lung

Ventilation StrategiesParameter Suggested Guidelines/ Exceptions

Tidal volume 5-6 mL/kgMaintain:

  Peak airway pressure < 35 cm H2O

  Plateau airway pressure < 25 cm H2O

Positive end-expiratory pressure

5 cm H2OPatients with COPD: no added PEEP

Respiratory rate 12 breaths/min

Maintain normal PaCO2; Pa-ETCO2 will usually increase 1-3 mm Hg during OLV

Mode Volume or pressure controlled

Pressure control for patients at risk of lung injury (e.g., bullae, pneumonectomy, post lung transplantation)

Postoperative mangement- Analgesia

• Systemic Analgesia – Opioids– Nonsteroidal Anti-inflammatory Drugs– Ketamine– Dexmedetomidine

• Local Anesthetics/Nerve Blocks – Intercostal Nerve Blocks– Intrapleural Analgesia– Epidural Analgesia– Paravertebral Block

Thoracic Epidural Analgesia

• Better preservation of the functional residual volume

• Efficient mucociliary clearance• Alleviation of the inhibiting reflexes acting

on the diaphragm • prevention of atelectasis and secondary

infections

Postoperative Complications

• Early Major Complications– Torsion of a remaining lobe after lobectomy– Dehiscence of a bronchial stump– Hemorrhage from a major vessel– Respiratory Failure– Cardiac Herniation

Anaesthetic management of bronchopleural fistula 

Bronchopleural fistulaCommunication from major bronchus to pleural spaceCommonly associated with pneumonectomy, trauma, abscess or empyemaRelevant complications

Pus may contaminate other lung-associated injuries with trauma

SurgeryUsually semi-electiveResuturing of bronchial stump, muscle flap to stump, drainage of abscess

High risk surgery requiring GA and one-lung ventilation

If incidental surgery, GA may be avoided, regional preferred

Positioning still important to avoid soiling

PatientCommonly debilitated, may have coexistent

medical problemsRespiratory function assessed

Clinical, spirometry, ABGsRoutine assessment for thoracic surgery

Consideration of epidural

Decision to proceedRespiratory function optimizedChest drain inserted to avoid tension

pneumothorax and drain pleural collection

InductionObjectives

Maintain oxygenation and ventilation, avoid tension pneumothorax

Avoid soiling good lungProtection of lung requires DLT, bronchial lumen to good

sideSmall leak without infection may be manageable with

single-lumen ETTPaediatric patients are typically too small for DLT or

FOB --> blocker or endobronchial intubationFistula reduces effectiveness of mask IPPV, so

spontaneous ventilation Ideally awake DLT intubation

Topical local anaesthetic to airway Position head-up and bad side down Sedation for intubation

Alternatively spontaneously ventilating GA with DLT insertion when deep

Verification of DLT position with differential ventilation or FOB

MaintenanceIPPV to healthy lungLung with fistula may benefit from small VT

ventilation or CPAP below critical pressure for fistula or HFJV

EmergenceAvoid high airway pressures if fistula has been

repaired Hand ventilation or SIMV

PostoperativeEpidural analgesiaHDU monitoring post-op

High incidence of arrhythmia post-thoracotomy

THANK YOU