1. Oxygen Therapy

Hypoxemia accelerates HbS polymerization and vaso-occlusion. Targeted oxygen delivery is a cornerstone therapy to reduce sickling, improve tissue oxygenation, and prevent the progression to acute chest syndrome (ACS).

Rationale and Targets

The primary goal is to increase the partial pressure of arterial oxygen (PaO₂), which reduces the concentration of deoxygenated HbS and slows the sickling process. The clinical targets are an oxygen saturation (SpO₂) ≥ 95% and a PaO₂ between 80–100 mm Hg.

Modalities and Monitoring

• Low-flow nasal cannula (1–6 L/min): Suitable for mild hypoxemia.
• High-flow nasal oxygen (HFNO): Preferred for moderate hypoxemia or to prevent progression; provides heated, humidified oxygen up to 60 L/min with adjustable FiO₂.
• Noninvasive ventilation (BiPAP): Used for patients with significant work-of-breathing or impending hypercapnic failure.
• Mechanical Ventilation: Reserved for severe respiratory failure (e.g., PaO₂ < 60 mm Hg on FiO₂ > 0.6), altered mental status, or muscular exhaustion.

Continuous pulse oximetry is mandatory. Arterial blood gases (ABGs) should be checked on initiation of therapy and after any significant clinical change to ensure adequate oxygenation without inducing severe hypercapnia.

2. Pulmonary Hygiene

Pain-induced splinting and opioid-related hypoventilation are major risk factors for atelectasis, which is a precursor to ACS. Proactive pulmonary toilet is essential to maintain alveolar recruitment and prevent this deadly complication.

Key Interventions

• Incentive Spirometry (IS): The cornerstone of pulmonary hygiene. Patients should perform 10 deep inspirations every hour while awake. Documenting hourly volumes helps track adherence and effort. Automated devices with visual feedback can improve compliance.
• Chest Physiotherapy & Bronchodilators: Percussion and vibration can help mobilize secretions. Nebulized albuterol may be used as needed for patients with evidence of bronchospasm.
• Early Mobilization: Encourage upright sitting and ambulation as soon as pain control allows. For bedbound patients, frequent turning and repositioning (every 2 hours) improves ventilation to different lung regions.

3. Fluid and Hemodynamic Management

The goal of fluid management is to achieve euvolemia. While restoring intravascular volume can lower blood viscosity and improve microvascular flow, overhydration is a significant risk, potentially leading to pulmonary edema and worsening ACS. A cautious, monitored approach is critical.

Strategy and Monitoring

• Initial Resuscitation: For patients with signs of dehydration, an initial bolus of isotonic crystalloid (e.g., 10–20 mL/kg over 1–2 hours) is appropriate.
• Maintenance Fluids: After initial resuscitation, fluids should be tailored to match ongoing losses, aiming for a urine output ≥ 0.5 mL/kg/h.
• Dynamic Assessment: In mechanically ventilated patients, dynamic indices like stroke volume variation (SVV) or pulse pressure variation (PPV) are superior to static pressures (like CVP) for predicting fluid responsiveness. Bedside echocardiography can also assess fluid status non-invasively.
• Diuresis: If signs of volume overload appear (e.g., rising oxygen needs, new crackles on exam), judicious use of diuretics like furosemide is indicated.

4. Thromboprophylaxis

Critically ill patients with sickle cell disease (SCD) are in a hypercoagulable state and have a significantly elevated risk for venous thromboembolism (VTE). Pharmacologic prophylaxis is standard of care for all ICU patients with SCD unless a major contraindication exists.

Pharmacotherapy and Monitoring

Mechanical prophylaxis with sequential compression devices (SCDs) should be used when anticoagulation is contraindicated (e.g., active bleeding, severe thrombocytopenia with platelets < 50 × 10⁹/L).

5. Stress Ulcer Prophylaxis

The risk of stress-related mucosal bleeding is increased in critically ill patients, particularly those with major risk factors like prolonged mechanical ventilation or coagulopathy. Acid-suppressive therapy is used to mitigate this risk.

Indications and Agents

Prophylaxis is indicated for patients on mechanical ventilation for >48 hours or those with coagulopathy (e.g., platelets < 50 × 10⁹/L, INR > 1.5).

6. Infection Prevention and Control

Patients with SCD are often functionally asplenic and immunocompromised, placing them at high risk for overwhelming infection. Strict adherence to infection control bundles and appropriate antimicrobial stewardship are critical in the ICU.

Core Strategies

• Aseptic Technique: Meticulous adherence to central line insertion and maintenance bundles is proven to reduce rates of central line-associated bloodstream infections (CLABSI).
• Vaccination Status: Verify and update vaccinations against encapsulated organisms, including pneumococcus, meningococcus, and Haemophilus influenzae.
• Antibiotic Stewardship: Continue prophylactic penicillin for asplenic patients. For suspected infections, use broad-spectrum empiric therapy but de-escalate promptly based on culture results to minimize resistance and side effects.

7. Multidisciplinary Coordination

A coordinated, interdisciplinary team approach is proven to streamline care, anticipate complications, and reduce ICU length of stay for patients with SCD. Daily rounds should involve all key stakeholders.

8. Monitoring and Early Warning Systems

Continuous monitoring and surveillance for subtle changes allow for preemptive intervention before overt organ failure develops. A high index of suspicion is required.

Surveillance Parameters

• Vital Signs: Close tracking of trends in respiratory rate, heart rate, and oxygen saturation. A rising oxygen requirement is a critical early warning sign of impending ACS.
• Laboratory Monitoring: Daily monitoring of LDH and bilirubin (hemolysis markers), creatinine (renal function), and liver function tests can detect subclinical organ injury.
• Early Warning Scores: Utilize standardized scores like the Sequential Organ Failure Assessment (SOFA) or National Early Warning Score (NEWS) to trigger escalation protocols and rapid response team activation for any acute deterioration.