What are the treatments for metabolic acidosis and decompression sickness?

Treatment of Metabolic Acidosis and Decompression Sickness

Decompression Sickness Treatment

For decompression sickness, immediately administer supplementary oxygen and arrange urgent hyperbaric oxygen therapy, which is the definitive treatment. 1, 2

Immediate Management

• Administer 100% oxygen immediately upon recognition of decompression sickness symptoms, as this is recommended by the American Heart Association for first aid providers with specific diving training 1
• Provide appropriate resuscitation with oral or intravenous fluids to maintain adequate hydration and tissue perfusion 2
• Arrange urgent transfer to a hyperbaric oxygen facility, as hyperbaric oxygen is the definitive treatment for decompression sickness 2

Clinical Presentation to Assess

• Obtain detailed history of the diving/altitude event and precise timing of symptom onset 2
• Perform careful neurological examination, as manifestations range from joint/muscle pain, lymphedema, and skin rash to severe neurological abnormalities and cardiorespiratory collapse 2
• Monitor for progression of symptoms during transport 2

---

Metabolic Acidosis Treatment

Treatment of metabolic acidosis must be directed at the underlying cause rather than routine bicarbonate administration, as sodium bicarbonate has not demonstrated mortality benefit in most acute organic acidoses. 3

Etiology-Based Treatment Approach

Diabetic Ketoacidosis

• Focus on insulin therapy, fluid resuscitation, and electrolyte replacement as the primary interventions 3, 4
• Administer continuous intravenous insulin as the standard of care for critically ill and mentally obtunded patients 3
• Prioritize restoration of circulatory volume and tissue perfusion over direct pH correction 3
• Avoid bicarbonate administration in diabetic ketoacidosis, as it has not been shown to improve resolution of acidosis or time to discharge 3, 4
• The only exception is pH < 6.9, where bicarbonate may be considered (1-2 mEq/kg IV given slowly in children) 3

Chronic Kidney Disease-Associated Acidosis

• Treat when serum bicarbonate is consistently < 18 mmol/L to prevent bone and muscle metabolism abnormalities 3, 4
• Administer oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) to effectively increase serum bicarbonate concentrations 3
• Maintain serum bicarbonate at or above 22 mmol/L in maintenance dialysis patients 3
• Monitor serum bicarbonate levels monthly in maintenance dialysis patients 3

Severe Acidosis with Acute Kidney Injury

• Hemodialysis is the definitive treatment for pH < 7.20 with acute kidney injury, as it simultaneously corrects acidemia, removes uremic toxins, and manages volume status 3
• Do not delay dialysis while attempting medical management, as the acidosis is refractory to conservative measures 3
• All patients require ICU-level care with nephrology consultation for urgent dialysis 3

Lactic Acidosis and Shock

• Focus on correcting the underlying cause: hemorrhage control, source control of infection, and restoration of adequate tissue perfusion 5
• Use balanced fluid resuscitation with attention to plasma/packed red blood cell ratios in massive hemorrhage 5
• Avoid hypotonic fluids (e.g., glucose solutions) for fluid resuscitation 3, 5
• The only effective treatment for organic acidosis is cessation of acid production via improvement of tissue oxygenation 6

Sodium Bicarbonate Administration Guidelines (When Indicated)

Bicarbonate therapy should always be planned in a stepwise fashion, as the degree of response from a given dose is not precisely predictable. 7

Cardiac Arrest

• Administer rapid intravenous dose of one to two 50 mL vials (44.6 to 100 mEq) initially 7
• Continue at a rate of 50 mL (44.6 to 50 mEq) every 5 to 10 minutes if necessary, as indicated by arterial pH and blood gas monitoring 7
• In cardiac arrest, the risks from acidosis exceed those of hypernatremia 7

Less Urgent Metabolic Acidosis

• Infuse 2 to 5 mEq/kg body weight over 4 to 8 hours initially 7
• Aim for total CO2 content of about 20 mEq/liter at the end of the first day, as achieving normal or above-normal values within the first day is very likely to be associated with grossly alkaline blood pH 7
• Monitor therapy by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics, and cardiac rhythm 7

Critical Monitoring Requirements

• Monitor electrolytes, particularly potassium levels, as acidosis causes hyperkalemia due to transcellular potassium shift 3, 4
• Be aware that bicarbonate administration may worsen intracellular acidosis, reduce ionized calcium, and produce hyperosmolality 3, 4
• Avoid using furosemide unless hypervolemia, hyperkalemia, and/or renal acidosis are present 3
• Avoid using dopamine in an attempt to improve renal function 3

Common Pitfalls to Avoid

• Do not attempt full correction of low total CO2 content during the first 24 hours, as this may be accompanied by unrecognized alkalosis due to delayed readjustment of ventilation 7
• Do not use bicarbonate routinely in acute organic acidoses, as it has failed to reduce morbidity and mortality despite improvement in acid-base parameters 6
• Avoid citrate alkali salts in CKD patients exposed to aluminum salts, as they may increase aluminum absorption 3