What are the guidelines for ventilator management in patients with acute cerebral stroke (CVA)?

From the Guidelines

Ventilator management for acute stroke patients should prioritize maintaining adequate oxygenation and preventing secondary brain injury, with a focus on supplemental oxygen to maintain oxygen saturation ≥94% 1.

Key Recommendations

• Initial ventilator settings should include a tidal volume of 6-8 mL/kg of ideal body weight, respiratory rate of 12-16 breaths per minute, PEEP of 5-8 cmH2O, and FiO2 titrated to maintain SpO2 >94% 1.
• Target PaO2 should be 80-100 mmHg and PaCO2 35-45 mmHg, as both hypoxemia and abnormal CO2 levels can worsen cerebral blood flow and neurological outcomes 1.
• For patients with increased intracranial pressure (ICP), mild hyperventilation (PaCO2 30-35 mmHg) may be temporarily used as a rescue measure, but prolonged hyperventilation should be avoided due to risk of cerebral ischemia 1.
• Head elevation to 30 degrees helps optimize cerebral perfusion and reduce ICP 1.
• Sedation with propofol (starting at 5-50 mcg/kg/min) or dexmedetomidine (0.2-0.7 mcg/kg/hr) is preferred as they allow for neurological assessments 1.
• Daily sedation interruptions should be performed when safe to evaluate neurological status 1.
• Regular arterial blood gas monitoring is essential to guide ventilator adjustments 1.
• Lung-protective strategies should be employed to prevent ventilator-associated pneumonia, including oral care with chlorhexidine, elevation of the head of bed, and consideration of early tracheostomy (within 7-10 days) if prolonged ventilation is anticipated 1.

Rationale

The most recent and highest quality study, a systematic review and synthesis of global stroke guidelines published in 2023 1, provides the basis for these recommendations. This study emphasizes the importance of maintaining adequate oxygenation and preventing secondary brain injury in acute stroke patients. The use of supplemental oxygen to maintain oxygen saturation ≥94% is a key recommendation, as it can help prevent hypoxia and worsen brain injury. The study also highlights the importance of lung-protective strategies to prevent ventilator-associated pneumonia.

Additional Considerations

Tracheal intubation is indicated for a compromised airway or insufficient ventilation due to impaired alertness or bulbar dysfunction 1. Supplemental oxygen should be provided to maintain oxygen saturation ≥94% 1. Hypotension and hypovolemia should be corrected to maintain systemic perfusion levels necessary to support organ function 1. Emergency treatment of hypertension is indicated if there is concomitant acute myocardial ischemia, aortic dissection, or preeclampsia/eclampsia 1. Capillary blood glucose should be checked immediately in suspected stroke, and hypoglycemia (glucose below 60 mg/dL or 3.3 mmol/L) should be treated with IV dextrose 1. Electrocardiography and other blood tests (complete cell count, serum electrolytes and creatinine, INR and partial thromboplastin time, serum troponin) should be obtained, but should not delay the initiation of reperfusion therapy 1. A stroke severity rating scale (e.g. NIHSS) should be used in the ED 1. All patients with suspected acute stroke should undergo brain imaging (head CT or brain MRI) without delay upon hospital arrival and before receiving any specific treatment for stroke 1. Reperfusion therapy for AIS should be initiated as soon as possible in eligible patients 1. IV alteplase (0.9 mg/kg, maximum dose 90 mg over 60 min with initial 10% of dose given as bolus over 1 min) is recommended for selected patients who can be treated within 4.5 h of ischemic stroke symptom onset or last known well 1. Patients with AIS and acute hypertension who are otherwise eligible for IV thrombolysis should have their BP lowered below 185/110 mm Hg before IV thrombolysis is initiated 1. Eligible patients should receive IV thrombolysis even if mechanical thrombectomy is being considered 1. Do NOT evaluate responses to IV thrombolysis before proceeding with catheter angiography for mechanical thrombectomy 1. Patients with clinically suspected LVO should have non-invasive angiography (e.g. CTA) 1. Patients with AIS within 6–24 h of time last known well who have a LVO in the anterior circulation should have advanced imaging (CTP or DW-MRI, with or without MRI perfusion) to determine eligibility for mechanical thrombectomy 1.

From the Research

Ventilator Management for Acute Stroke

• The optimal mechanical ventilator strategy for patients with acute stroke remains unclear 2.
• A protective ventilatory strategy, which includes a tidal volume of 6-8 mL/kg predicted body weight, positive end-expiratory pressure, and rescue recruitment maneuvers, may be beneficial for brain-damaged patients, including those with stroke 2.
• Principles of lung-protective ventilation include:
  • Prevention of volutrauma (tidal volume 4 to 8 ml/kg predicted body weight with plateau pressure <30 cmH2O)
  • Prevention of atelectasis (positive end-expiratory pressure ≥5 cmH2O, as needed recruitment maneuvers)
  • Adequate ventilation (respiratory rate 20 to 35 breaths per minute)
  • Prevention of hyperoxia (titrate inspired oxygen concentration to peripheral oxygen saturation (SpO2) levels of 88 to 95%) 3
• Lung-protective mechanical ventilation is recommended as an initial approach to mechanical ventilation in both perioperative and critical care settings 3.
• The use of alveolar-recruitment maneuvers to improve oxygenation in patients with acute lung injury/acute respiratory distress syndrome is controversial, but sighs superimposed on lung-protective mechanical ventilation with optimal PEEP may improve oxygenation and static compliance 4.
• A multicenter randomized clinical trial (PROLABI) found that lung-protective mechanical ventilation in patients with severe acute brain injury did not reduce mortality, percentage of patients weaned from mechanical ventilation, or incidence of ARDS, and was not beneficial in terms of neurological outcomes 5.
• A retrospective review of trauma patients mechanically ventilated for > or = 4 days found that a strict ARDS Network ventilation strategy (VT < 6 mL/kg) is not always followed, but a low plateau/peak pressure strategy is used, which is a form of lung protective ventilation 6.