Restrictive lung disease

Question 1

What are the restrictive diseases?

Answer 1

1. Acute Intrinsic
pulmonary edema
ARDS, 
2. Chronic Intrinsic 
diseased lung parenchyma - sarcoidosis
3. Chronic Extrinsic
chest wall, intra-abdominal & neuromuscular diseases
4. Disorders of the Pleura and Mediastinum

Question 2

Pre-operative Assessment and Optimization

Answer 2

Exercise tolerance and baseline dyspnea
PFTs, flow-volume loops and ABG may be useful to grade severity
Factors that signal increased risk:
Decrease in VC

Question 3

NM disorders and anesthetic considerations

Answer 3

Ineffective cough
 impaired clearance of secretions
 pneumonia
 respiratory failure may result
Very sensitive to CNS depressants

Question 4

Anesthetic management of restrictive disease

Answer 4

Positive-pressure ventilation results in high airway pressures in order tp expand stiff lungs
Overall mechanical ventilation should combine lower tidal volumes and rapid rates
1. Pre-Induction
Titrate pre-medications carefully to reduce ventilatory depression – very little reserve
2. Regional anesthesia
>T10 level
pt will have a loss of accessory respiratory muscles which may be crucial to spontaneous ventilation in these patients
3. N2O - must be used with caution secondary to risk of barotrauma (pneumothorax)
IV/maintenance agents
– shorter acting agents preferred to minimize post-operative respiratory depression
4. Volatile Agents
– accelerated uptake (decreased FRC and often increased RR)

Question 5

Anesthetic management: Ventilation

Answer 5

1. Mechanical ventilation w/ETT
   will help maintain optimal oxygenation and ventilation
2. Pre-oxygenation very important
   – decreased FRC/lower O2 stores
   SaO2 drops quickly with apnea
3. Expect increased peak airway pressures as poorly compliant lungs are ventilated mechanically
   Decrease volume (4-8 ml/kg)
   increase rate (14-18 breaths per minute)
   attempt to keep end-inspiratory plateau pressure

Question 6

Extubation criteria regarding restrictive disease

Answer 6

Extubate only after criteria met:
Adequate PaO2 > 60 mmHg
PaCO2 300ml 
VC > 10-15ml/kg
Adequate level of consciousness and muscle strength- example- sustained head lift > 5 seconds
Full reversal of neuromuscular blockade

Question 7

Post -Anesthetic Management

Answer 7

Post-op Pulmonary problems are primarily restrictive
Decreased lung volumes
Consider abdominal impingement on movement of diaphragm
Abnormal resp pattern with shallow breathing with rapid respirations
Consider surgical site-this is an important risk factor for development of of Post-operative pulmonary complications
Decreased lung volumes and impaired cough put patient at risk for post-operative respiratory failure
Supplemental O2 for transport
Treat pain adequately but avoid excessive respiratory depression
Low threshold for:
Post-op mechanical ventilation
Monitored post-operative bed