Role of Sodium Bicarbonate in Sickle Cell Crisis

The theoretical rationale

"They are treated by correcting factors that enhance sickling: dehydration, hypoxia, and acidosis. This is done through hydration, alkalization, and the administration of supplemental oxygen." - Henry's Clinical Diagnosis and Management by Laboratory Methods, p. 909-945

What the evidence actually shows

• Mann & Stuart (1974, Pediatrics) tested oral sodium bicarbonate as prophylaxis against sickle cell crisis (PMID 4592679).
• A double-blind trial of rapid IV sodium bicarbonate infusion for painful sickle crises found it did not relieve the symptoms of painful crises compared with placebo.
• Similarly, in sickle cell-associated priapism, hematologists have "begun to question the emphasis on intravenous hydration, sodium bicarbonate for alkalinization, and exchange transfusion as first-line therapy," favoring hydroxyurea and other approaches instead - Campbell-Walsh-Wein Urology, p. (Ischemic Priapism section).

Current standard practice

• Aggressive analgesia (opioids ± NSAIDs)
• IV isotonic fluid hydration to correct dehydration and ongoing losses
• Supplemental oxygen only if hypoxic (SpO2 <92%) - oxygen has not been shown to alter crisis outcomes if saturations are normal
• Treating the precipitant (infection, hypoxia, etc.)
• Transfusion (simple or exchange) reserved for specific complications (acute chest syndrome, aplastic/splenic sequestration crisis, severe anemia, stroke), not routine uncomplicated pain crisis

Risks of using bicarbonate

Bottom line

Managing Sickle Cell Crises

1. Vaso-occlusive (painful) crisis - the most common type

• Analgesia is the priority - emergency physicians frequently under-dose pain in these patients. Use the patient's individualized pain plan if one exists.
  • Mild-moderate pain: NSAIDs
  • Moderate-severe pain: IV opioids (morphine, hydromorphone). Use fentanyl if renal/hepatic dysfunction. Ketamine can help if response to opioids is poor.
  • Patient-controlled analgesia (PCA) is preferred over intermittent dosing; give as-needed doses for breakthrough pain
• IV hydration for dehydration - though evidence on the ideal fluid type/volume is limited; avoid over-hydration (fluid overload raises acute chest syndrome risk)
• Oxygen only if hypoxic (SpO2 <92% or below baseline) - not routinely needed
• Incentive spirometry to reduce risk of acute chest syndrome
• Identify and treat any precipitant (infection, etc.)
• Sodium bicarbonate/"alkalinization" is not part of current standard protocols (see prior discussion - trials failed to show benefit)
• Most uncomplicated crises are managed without transfusion; simple transfusion is reserved for symptomatic anemia (Hb <10 g/dL with symptoms) rather than pain alone
• Harriet Lane Handbook, 23rd ed., p. 483

2. Acute chest syndrome (a form of vaso-occlusive crisis in the lungs)

• Empiric antibiotics: cephalosporin (cefuroxime/cefotaxime) plus a macrolide (covers atypicals like Mycoplasma, Chlamydia pneumoniae)
• Oxygen to keep SpO2 >92-95% (even if baseline saturation is normal)
• Adequate hydration but watch for fluid overload - use diuretics if it develops
• Aggressive analgesia + incentive spirometry (reduces chest splinting)
• Consider bronchodilators
• Simple transfusion if anemic; exchange transfusion for more severe or worsening cases (reduces blood viscosity and improves oxygenation)
• High-dose dexamethasone use is controversial
• Close monitoring - up to 13% require mechanical ventilation, with ~19% mortality in that subgroup
• Miller's Anesthesia, 10e; Murray & Nadel's Textbook of Respiratory Medicine

3. Aplastic crisis

• Immediate simple red cell transfusion is the key treatment for severe anemia
• Supportive care, monitor for recovery of marrow function

4. Splenic sequestration crisis

• Admit for serial abdominal exams
• IV fluid resuscitation
• Type and screen, transfuse if needed
• Recurrent sequestration may prompt consideration of splenectomy

5. Priapism (ischemic)

General/preventive measures across all crises

• Prophylactic penicillin (children), pneumococcal/other vaccinations
• Hydroxyurea to reduce crisis frequency (increases fetal hemoglobin)
• Avoid known triggers: dehydration, hypoxia, extreme cold, acidosis, strenuous exertion
• Individualized outpatient pain management plans reduce reliance on ED visits

Current guideline sources

Pediatric Diclofenac Dosing

Oral (immediate release) - for pain/inflammation (e.g., juvenile idiopathic arthritis, general pain)

IV/deep IM (postoperative pain)

Rectal suppository

Age/weight-banded practical dosing (commonly cited)

• Ages 9-11 years (35-44 kg): dosed up to 3 times/day
• Ages 12-16 years (45-55 kg): 25 mg orally, up to 3-4 times/day
• ≥12 years (US labeling, Zipsor capsules only): 25 mg PO 4 times daily as needed

Important cautions

1. US labeling gap: Standard oral diclofenac (Voltaren, Cataflam, etc.) is not FDA-approved for use in children in the US - "the drug is not recommended for children, nursing mothers, or pregnant women" (Goodman & Gilman's Pharmacological Basis of Therapeutics, p. 762-763). The one exception is Zipsor (diclofenac potassium liquid-filled capsule), approved for acute pain in children ≥12 years at 25 mg PO four times daily PRN. Below 12 years, safety/efficacy have not been established in the US.
2. Outside the US, particularly in Europe (BNF), diclofenac is used from 6 months of age for rheumatic disease under specialist guidance.
3. Monitor liver transaminases during the first 8 weeks of therapy - significant transaminase elevation occurs in about 4% of users, and rare severe hepatotoxicity has been reported.
4. Watch for GI toxicity, fluid retention/edema, and renal effects - important if the child is dehydrated, has any renal impairment, or is on other nephrotoxic drugs.
5. Avoid in active GI bleeding, significant renal or hepatic impairment, and in the setting of dehydration/hypovolemia.