Apnea testing in the diagnosis of brain death

Clinical and physiological observations

View More View Less
  • 1 Neurology-Neurosurgery Intensive Care Unit, Departments of Neurology, Anesthesia, and Nursing, Massachusetts General Hospital, Boston, Massachusetts
Restricted access

Purchase Now

USD  $45.00

JNS + Pediatrics - 1 year subscription bundle (Individuals Only)

USD  $505.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $600.00
Print or Print + Online

✓ The absence of spontaneous respiration is a crucial determinant in the diagnosis of brain death, but standardized criteria for apnea testing have not been established. Guidelines are proposed based on the results of 51 apnea tests and associated physiological measurements. In patients who fulfilled all other conventional criteria for brain death, three exhibited non-repetitive back arching and shoulder shrugging when CO2 pressures reached 41 to 51 mm Hg during apnea testing. These respiratory-like movements were ineffective for ventilation and were not reproducible on the following day at the same or higher pCO2. The nature of these movements, evoked potential testing, and autopsy results suggest that they were not triggered by normal medullary centers, and that these patients were, in fact, brain-dead. In four other patients with severe brain damage sparing only the medulla, normal spontaneous ventilation resumed at CO2 pressures of 30 to 39 mm Hg (mean 34 mm Hg). High arterial oxygen tension raised this apnea point slightly, but spontaneous breathing always began at CO2 pressures lower than 40 mm Hg. This level is therefore adequate to stimulate medullary respiration in patients with severe brain damage who are not brain-dead. In brain-dead patients, pCO2 rises slowly during apnea (2.58 ± 0.85 mm Hg/min), in part because CO2 production is diminished (1.8 ± 0.23 ml/min/kg). These data allow estimation of a desired length of an apnea test and standardized interpretation of results.

JNS + Pediatrics - 1 year subscription bundle (Individuals Only)

USD  $505.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $600.00

Contributor Notes

Address reprint requests to: Allan H. Ropper, M.D., Department of Neurology, Massachusetts General Hospital, Fruit Street, Boston, Massachusetts 02114.
  • 1.

    Allen N, , Burkholder J, & Comiscioni J: Clinical criteria of brain death. Ann NY Acad Sci 315:7096, 1978 Allen N, Burkholder J, Comiscioni J: Clinical criteria of brain death. Ann NY Acad Sci 315:70–96, 1978

    • Search Google Scholar
    • Export Citation
  • 2.

    Conference of Royal Colleges and Faculties of the United Kingdom: Diagnosis of brain death. Lancet 2:10691070, 1976 Conference of Royal Colleges and Faculties of the United Kingdom: Diagnosis of brain death. Lancet 2:1069–1070, 1976

    • Search Google Scholar
    • Export Citation
  • 3.

    Frumin MJ, , Epstein RM, & Cohen G: Apneic oxygenation in man. Anesthesiology 20:789798, 1959 Frumin MJ, Epstein RM, Cohen G: Apneic oxygenation in man. Anesthesiology 20:789–798, 1959

    • Search Google Scholar
    • Export Citation
  • 4.

    Goldie W, , Chiappa KH, & Young RR, et al: Brainstem auditory and short-latency somatosensory evoked responses in brain death. Neurology 31:248256, 1981 Goldie W, Chiappa KH, Young RR, et al: Brainstem auditory and short-latency somatosensory evoked responses in brain death. Neurology 31:248–256, 1981

    • Search Google Scholar
    • Export Citation
  • 5.

    Hanks EC, , Ngai SH, & Fink BR: The respiratory threshold for carbon dioxide in anesthetized man. Anesthesiology 22:393397, 1961 Hanks EC, Ngai SH, Fink BR: The respiratory threshold for carbon dioxide in anesthetized man. Anesthesiology 22:393–397, 1961

    • Search Google Scholar
    • Export Citation
  • 6.

    Hill DW, & Tilsley C: A comparative study of the performance of five commercial blood-gas and pH electrode analysers. Br J Anaesth 45:647654, 1973 Hill DW, Tilsley C: A comparative study of the performance of five commercial blood-gas and pH electrode analysers. Br J Anaesth 45:647–654, 1973

    • Search Google Scholar
    • Export Citation
  • 7.

    Plum F, , Brown HW, & Snoep E: Neurologic significance of posthyperventilation apnea. JAMA 181:10501055, 1962 Plum F, Brown HW, Snoep E: Neurologic significance of posthyperventilation apnea. JAMA 181:1050–1055, 1962

    • Search Google Scholar
    • Export Citation
  • 8.

    Schafer JA, & Caronna JJ: Duration of apnea needed to confirm brain death. Neurology 28:661666, 1978 Schafer JA, Caronna JJ: Duration of apnea needed to confirm brain death. Neurology 28:661–666, 1978

    • Search Google Scholar
    • Export Citation

Metrics

All Time Past Year Past 30 Days
Abstract Views 438 163 7
Full Text Views 301 13 0
PDF Downloads 124 12 0
EPUB Downloads 0 0 0