eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Critical Care

Acidosis, Respiratory: Follow-up

Author: Margaret A Priestley, MD, Assistant Professor of Clinical Anesthesiology and Critical Care, University of Pennsylvania School of Medicine; Clinical Director, Pediatric Intensive Care Unit, The Children's Hospital of Philadelphia
Coauthor(s): Ronald Litman, DO, Associate Professor of Anesthesiology and Pediatrics, University of Pennsylvania School of Medicine
Contributor Information and Disclosures

Updated: Jan 5, 2009

Follow-up

Further Inpatient Care

  • Patients with acute respiratory acidosis require admission to the ICU for close monitoring and possible advanced airway management with mechanical respiratory support.
  • Avoid use of narcotics, sedatives, or other respiratory depressants when the patient is breathing spontaneously.
  • Correct electrolyte abnormalities associated with muscle weakness, such as hypophosphatemia, hypokalemia, hypomagnesemia, and hypocalcemia.
  • Maximize nutrition, but avoid overfeeding and high carbohydrate content because these can increase CO2 production.
  • If a metabolic alkalosis develops during diuretic therapy, correct it by replacing chloride and, if needed, careful replacement of potassium.

Further Outpatient Care

  • For chronic respiratory acidosis, frequent follow-up with pulmonary function testing is necessary to provide a reference baseline and to monitor for changes during acute illness.
  • Noninvasive positive-pressure ventilation is an effective home therapy for chronic respiratory failure caused by obstructive sleep apnea, obesity hypoventilation syndrome, or neuromuscular disease. Therapy can be continuous, intermittent with certain activities, or nocturnal.
  • Home nursing can provide additional care.

Complications

  • Respiratory acidosis may precede acute respiratory failure and possible cardiovascular failure.
  • Convulsions may result if PaCO2 levels are restored too quickly in patients with chronic hypercapnia.
  • Posthypercapnic alkalosis can occur in patients with chronic hypercapnia if PaCO2 is rapidly reduced with mechanical ventilation.
    • The kidneys have a relatively slow mechanism to correct the HCO3 - excess.
    • The metabolic alkalosis can be treated by replacing chloride, potassium, or by increasing renal HCO3 - excretion with acetazolamide. Care must be taken not to correct a compensating metabolic alkalosis with out addressing the underlying respiratory acidosis.
  • If tracheal intubation is required in a spontaneously breathing person with high minute ventilation, care must be taken to maintain that level of minute ventilation to avoid a sudden increase in PaCO2 that could contribute to hemodynamic instability, CNS injury, or cardiopulmonary arrest.
  • Tracheal intubation may lead to upper-airway edema and difficult extubation, especially in chronically ill patients with limited baseline pulmonary reserve.

Prognosis

  • Hypercapnic neurologic changes are reversible with no residual effect.
  • The prognosis depends on the underlying etiology
    • Respiratory acidosis can be an acute and transient event with no long-term sequelae if it is not associated with hypoxemia (eg, seizure and treatment-associated hypoventilation).
    • Respiratory acidosis may be associated with a chronic disease that has associated morbidity (eg, asthma or Duchenne muscular dystrophy).
    • Respiratory acidosis may be the sign of an irreversible progressive disease that leads to death (eg, idiopathic pulmonary hypertension).

Miscellaneous

Medicolegal Pitfalls

  • Failure to aggressively manage acute respiratory acidosis with assisted ventilation can lead to an otherwise avoidable respiratory and/or cardiovascular arrest.
  • Use of sedative medications in a nonintubated patient can worsen mild respiratory acidosis, leading to unrecognized CO2 narcosis.
  • Primary respiratory acidosis must be distinguished from secondary hypercapnia due to metabolic alkalosis.
  • Failure to consider a mixed acidosis can lead to missed therapies and diagnosis. Always critically analyze acid-base values by assessing the pH, PaCO2, and HCO3 - measurement.
 


More on Acidosis, Respiratory

Overview: Acidosis, Respiratory
Differential Diagnoses & Workup: Acidosis, Respiratory
Treatment & Medication: Acidosis, Respiratory
Follow-up: Acidosis, Respiratory
References
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References

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Further Reading

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Keywords

respiratory acidosis, carbon dioxide acidosis, CO2 acidosis, acute respiratory acidosis, chronic respiratory acidosis, hypercapnia, hypercarbia, supercarbia, acidemia, blood pH, acid-base balance, pCO2, minute ventilation, bicarbonate, hypercapnic acidosis, arterial partial pressure of carbon dioxide, hypoxemia, PaCO2, depressed central respiratory drive, acute paralysis of the respiratory muscles, acute parenchymal lung and airway diseases, increased dead space, wasted ventilation, scoliosis, pulmonary vasoconstriction, supraventricular arrhythmias, hypoplastic left heart syndrome, hypercapnic encephalopathy, myasthenia gravis, bronchopulmonary dysplasia, asthma, emphysema, encephalitis, meningitis

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Contributor Information and Disclosures

Author

Margaret A Priestley, MD, Assistant Professor of Clinical Anesthesiology and Critical Care, University of Pennsylvania School of Medicine; Clinical Director, Pediatric Intensive Care Unit, The Children's Hospital of Philadelphia
Margaret A Priestley, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Ronald Litman, DO, Associate Professor of Anesthesiology and Pediatrics, University of Pennsylvania School of Medicine
Ronald Litman, DO is a member of the following medical societies: American Academy of Pediatrics, American Society of Anesthesiologists, and Society for Pediatric Anesthesia
Disclosure: Nothing to disclose.

Medical Editor

G Patricia Cantwell, MD, Associate Clinical Professor, Department of Pediatrics, University of Miami; Director of Pediatric Critical Care Medicine, Miller School of Medicine, Jackson Children's Hospital
G Patricia Cantwell, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Emergency Physicians, American Heart Association, American Trauma Society, National Association of EMS Physicians, Society of Critical Care Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Barry J Evans, MD, Assistant Professor of Pediatrics, Temple University Medical School; Director of Pediatric Critical Care and Pulmonology, Associate Chair for Pediatric Education, Temple University Children's Medical Center
Barry J Evans, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, American Thoracic Society, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

CME Editor

Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Professor of Clinical Pediatrics, State University of New York at Stony Brook; Director of Children's Sleep Services, Winthrop University Hospital
Mary E Cataletto, MD is a member of the following medical societies: American Academy of Pediatrics and American College of Chest Physicians
Disclosure: Shering Plough Pharmaceuticals Honoraria Consulting

Chief Editor

Timothy E Corden, MD, Associate Professor of Pediatrics, Co-Director, Policy Core, Injury Research Center, Medical College of Wisconsin; Associate Director, PICU, Children's Hospital of Wisconsin
Timothy E Corden, MD is a member of the following medical societies: American Academy of Pediatrics, Phi Beta Kappa, Society of Critical Care Medicine, and Wisconsin Medical Society
Disclosure: Nothing to disclose.

 
 
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