Mechanical Ventilation in Special Conditions

Mechanical Ventilation: Outline Head injury Chest Trauma Bronchopleural Fistula 3 3 3 3 3 3

Traumatic Brain Injury

Prevalence of extracerebral organ dysfunction in TBI

Cerebral Compliance Curve CPP= MAP-ICP Intracranial pressure CPP Intracranial volume

Cerebral Compliance Curve PaCO2 PaO2 CPP Cerebral Blood Flow 50 100 150

Head Injury: MV Monitoring Peak alveolar pressure, airway pressure, auto-PEEP PaCo2 end tidal PCO2 Intracranial pressure Jugular venous oxygen saturation Pulse oximetry Heart rate and systemic blood pressure

Hyperventilation in Traumatic Brain Injury Causes cerebral vasoconstriction Decreases cerebral blood flow Decreases cerebral blood volume Increases ICP Has been proven to be of benefit in head injuries

Head Trauma Cerebral physiology Hyperventilation ICP CBF Cerebral oxygenation : SJO2, PbrO2 Hyperventilation Lung protective strategy PEEP Extubation

Hyperventilation in TBI Chronic hyperventilation (PCO2 < 25) should be avoided Prophylactic hyperventilation (PCO2 < 35) in the first 24 h should be avoided May be necessary for a brief period with acute neurologic deterioration

Head Trauma + Lung protective strategy PEEP Extubation Hypoventilation  PCO2   ICP  No evidence of detrimental effect Use protective ventilation Observe ICP and CPP if PCO2▲ PEEP ICP  MAP  Depends on compliance Extubation LOC Cough Tracheal secretions +

+ Head Trauma Lung protective strategy PEEP Hypoventilation  PCO2   ICP  No evidence of detrimental effect Use protective ventilation Observe ICP and CPP if PCO2▲ PEEP ICP  MAP  Depends on compliance +

Head Trauma Extubation LOC Cough Tracheal secretions

Hyperventilation & CBF

Head Trauma CBF and ICP with hyperventilation

Head Trauma Extubation LOC Cough Tracheal secretions

Intrathoracic Pressure (-3 cm H2O) Venous Return MAP (90)= CO X SVR Decompressive Craniotomy Decrease Oxygen Demand Prevent seizure Sedation Treat pain Barbiturate coma Avoid hyperthermia ? hypothermia ICP= 10 ICP =30 CSF Drainage HOB > 30 degree Head in neutral position Vetriculostomy Decrease Brain Water Mannitol Avoid D5% Diuretics Vasoconstriction Pa co2 25-30 CPP = MAP – ICP Avoid ↑ Intrathoracic Pressure Suppress Valsalva maneuvers Suppress cough ↓ Mean airway pressure Minimize use of PEEP Treat distended abdomen Maintain adequate MAP Adequate CO Use inotropic Agents Adequate filling pressures Avoid hypotensive agents Treat infection abruptly Intrathoracic Pressure (-3 cm H2O) Venous Return MAP (90)= CO X SVR

Underlying lung disease CMV (A/C), PCV or VC, VT 4-8 mL/kg, FiO2 1, rate 20/min TI1s, PEEP 5 cm H2O yes CMV (A/C), PCV or VC, VT 4-8 mL/kg, FiO2 1, rate 15/min TI1s, PEEP 5 cm H2O no Titrate FiO2 for SpO2 ≥ 92% PCO2 >45 ↑ rate no ↓ rate yes ↓ VT Pplat > 30 <35 PaO2 35-45 no yes ↑ PEEP ↓ FiO2 >100 FiO2 > 0.6 <70 yes ICP < 20 70-100 FiO2 > 0.6 no ↑ FiO2 yes <20 >20 ICP More aggressive Medical therapy Slowly ↓ rate to initial setting no ICP >20 ↑ rate Maintain Ventilator Setting <20

Chest trauma Who Gets Admitted? Sternal fractures mediastinal injury Any 1th, 2nd, 3rd Rib fractures > 1 Rib fracture in any region Pulmonary contusion Subcutaneous emphysema Traumatic asphyxia Flail segment Arrhythmia or myocardial injury

Flail Chest

Flail chest

Flail Chest

BPF

BPF

BPF

Adverse effects of BPF in the ventilated patient Incomplete lung expansion Loss of TV Inability to remove CO2 Loss of PEEP Pleural space infection Factitious ventilator cycling

Guidelines for ventilator management in the patient with BPF Reduce MAP & RR Wean patient completely if possible Partial ventilatory support low-rate SIMV or PSV Minimize minute ventilation Use of permissive hypercapnia Avoid patient positions that increase the leak Treat bronchospasm Consider unconventional measures Bronchoscopic techniques HFV ILV

Independent lung ventilation

Independent Lung Ventilation