1. Respiratory Support

Altered consciousness and ARDS‐like physiology in CNS infections often necessitate mechanical ventilation. Securing the airway and controlling PaCO₂ are key to minimizing intracranial hypertension and secondary brain injury.

Indications for Mechanical Ventilation

• Glasgow Coma Scale (GCS) ≤ 8 or loss of protective airway reflexes
• Acute Respiratory Distress Syndrome (ARDS) criteria: PaO₂/FiO₂ ratio ≤ 300 mm Hg with bilateral infiltrates
• Impending respiratory failure: Rising PaCO₂ (> 50 mm Hg) or evident respiratory muscle fatigue

Brain-Protective Ventilator Settings

• Employ low tidal volume ventilation: 6 mL/kg of predicted body weight.
• Maintain plateau pressure ≤ 30 cm H₂O to prevent barotrauma.
• Target normocapnia: PaCO₂ between 35–45 mm Hg. Avoid permissive hypercapnia, which can increase cerebral blood flow and ICP.
• Use moderate PEEP (5–10 cm H₂O), but monitor ICP for any PEEP‐induced rises.
• Utilize continuous end-tidal CO₂ monitoring, confirmed with periodic arterial blood gas analysis.

Weaning and Spontaneous Breathing Trials (SBT)

• Consider weaning when ICP is controlled (< 20 mm Hg), MAP is stable, and ventilator support is minimal.
• Perform an SBT with pressure support of 5 cm H₂O for 30–120 minutes.
• Success is defined by: respiratory rate < 35 breaths/min, SpO₂ > 90% on FiO₂ ≤ 40%, and no signs of respiratory distress.
• Incorporate daily sedation interruptions to assess neurologic readiness for extubation.

2. Hemodynamic Management

Maintaining adequate cerebral perfusion pressure (CPP) is critical. This is achieved through timely fluid resuscitation and vasopressor therapy, while carefully balancing volume status to avoid exacerbating cerebral edema.

Fluid Resuscitation in Septic Shock

• Administer 30 mL/kg of isotonic crystalloid within the first 3 hours. Strictly avoid hypotonic fluids.
• Prefer balanced solutions (e.g., lactated Ringer’s) to mitigate the risk of hyperchloremic metabolic acidosis.
• Closely monitor serum sodium and osmolality to prevent iatrogenic hyponatremia and cerebral swelling.

Vasopressor Selection

• Norepinephrine is the first-line agent to achieve a Mean Arterial Pressure (MAP) of ≥ 65 mm Hg.
• Titrate vasopressor therapy to maintain a CPP > 60 mm Hg (CPP = MAP – ICP).
• Consider adding vasopressin at 0.03 units/min as a norepinephrine-sparing agent if high doses are required.

Monitoring Hemodynamics

• Utilize dynamic indices like pulse pressure variation (PPV) or stroke volume variation (SVV) over central venous pressure (CVP) to assess fluid responsiveness.
• Monitor lactate clearance; a drop of >10% within 2 hours is a positive sign of improving tissue perfusion.
• If available, transcranial Doppler can provide noninvasive trends of cerebral blood flow velocity.

3. Prevention of ICU-Related Complications

Immobilized patients with severe CNS infections are at high risk for venous thromboembolism (VTE), stress ulcers, and device-associated infections. Prophylactic measures are essential to reduce morbidity.

VTE Prophylaxis

Pharmacologic prophylaxis is standard unless contraindicated. Low-molecular-weight heparin (LMWH) is preferred.

Stress-Ulcer Prophylaxis

• Indications: Mechanical ventilation > 48 hours, or coagulopathy (INR > 1.5, platelets < 50,000/mm³).
• Agents: Pantoprazole 40 mg IV daily or famotidine 20 mg IV twice daily.
• Duration: Limit use to the period of high risk to reduce potential for C. difficile infection and pneumonia.

Central Line–Associated Infection Prevention

• Strictly adhere to the central line bundle: hand hygiene, maximal sterile barriers, chlorhexidine skin antisepsis, optimal site selection, and daily review of line necessity.
• Utilize ultrasound guidance for insertion and apply proper dressings.
• Remove all invasive lines as soon as they are no longer essential.

4. Management of Drug-Induced Organ Dysfunction

Several essential antimicrobials and supportive medications can cause renal or hepatic injury. Structured monitoring and proactive dose adjustments are necessary to preserve organ function.

Monitoring Protocols

• Perform daily serum creatinine (SCr) and liver function test (LFT) panels for patients on high-risk medications.
• Follow institutional protocols for therapeutic drug monitoring.
• Utilize established dosing algorithms for patients with renal or hepatic impairment.

5. Multidisciplinary Goals of Care

Structured family meetings and early involvement of palliative care specialists are crucial to ensure that supportive therapies align with patient priorities and to avoid nonbeneficial interventions.

Family Conferences

• Initiate a formal family conference within 72 hours of ICU admission.
• Include a multidisciplinary team: critical care, pharmacy, palliative care, and nursing.
• Set a clear agenda: discuss prognosis, review treatment options, understand patient values, and outline possible outcomes.

Ethical Considerations

• Openly discuss the burdens versus the benefits of all life-sustaining therapies.
• Systematically reevaluate the goals of care after any major clinical change or development.

Palliative Care Integration

• Integrate palliative care early to manage symptoms such as pain, agitation, and dyspnea alongside disease-directed therapy.
• Provide expert support for shared decision-making, especially concerning the limitation or withdrawal of invasive measures.