Transcutaneous and intra-arterial blood gas monitoring???a comparison during apnoea testing for the determination of brain death

Läng, Christoph; Heckmann, Josef G.; Erbguth, F.; Druschky, A.; Haslbeck, M.; Reinhardt, F; Winterholler, Martin

doi:10.1097/00063110-200203000-00012

Cited by 12 publications

(6 citation statements)

References 19 publications

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“…Although the ‘gold standard’ method is arterial blood gas sampling, this technique is invasive, and alternative endtidal pCO 2 monitoring via a mask is quite uncomfortable. Transcutaneous measurements have been found to be accurate in paediatric conditions [14]and to be able to detect pCO 2 changes during diagnosis of brain death [15]; thus, there is no reason to assume a systematic difference in recordings from young and old subjects. Therefore, we are confident that pCO 2 changes were not a factor for the different autoregulatory response in patients and controls in our study.…”

Section: Discussionmentioning

confidence: 99%

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Delayed Cerebrovascular Autoregulatory Response to Ergometer Exercise in Normotensive Elderly Humans

Heckmann

Brown²,

Cheregi³

et al. 2003

Cerebrovasc Dis

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Background: Relatively little is known about physiological cerebrovascular haemodynamics during physical stress in elderly healthy individuals. The aim of this study was to determine the effect of ergometer stress on cerebrovascular haemodynamics in elderly healthy individuals in comparison with young healthy individuals, using non-invasive methods. Methods: Continuous middle cerebral artery blood flow velocity (CBFV; transcranial Doppler ultrasound), beat-to-beat blood pressure, heart rate and transcutaneous pCO₂ were measured in response to 3 min ergometer exercise stress in 18 elderly healthy subjects (mean age ± SD 66.5 ± 5.8 years) and 18 healthy young subjects (mean age ± SD 29.4 ± 4.7 years). Pulsatility index (PI) was used as a parameter for cerebrovascular resistance. The subjects were in a supine position with an elevated trunk and performed exercise by pedalling on an ergometer, generating 75–100 W. Statistical analysis was carried out using MANOVA, a general linear model with repeated measures. Results: In both groups, blood pressure increased significantly (p < 0.001) with time during exercise, with no significant differences between the groups or regarding interaction (time sequence/group factor). Heart rate increased significantly with time during exercise (p < 0.001) and was significantly more prominent (p = 0.002) and prolonged (p < 0.001) in the young group. pCO₂ did not differ with time or between the groups and with regard to interaction. Mean CBFV (MFV) increased significantly during time (p < 0.001). Between the groups, there was no significant difference (p = 0.836), but with regard to interaction (time sequence/group factor), there was a significant delay in MFV increase in the group of young subjects (p = 0.002). The PI, a measure of cerebrovascular resistance, increased significantly with time without significant differences between the groups (p = 0.061), but was significantly delayed in the elderly regarding the interaction time sequence/group factor (p < 0.001). Conclusion: The cerebrovascular changes during ergometer exercise may reflect the combined activation of the cerebrovascular autoregulative mechanisms (predominantly neurogenic and myogenic). In healthy normotensive elderly subjects, cerebral autoregulatory capacity is retained but delayed in response to ergometer stress compared with young healthy subjects. We speculate that these findings may contribute to a higher risk of cerebral hypoperfusion in the elderly.

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Section: Discussionmentioning

confidence: 99%

“…pCO 2 was measured transcutaneously over the skin of the right forearm ulnar flexor muscle using a chemical method (Radiometer, Copenhagen, Denmark). This method has been found to be as accurate as endtidal CO 2 monitoring or arterial blood gas analysis [13, 14, 15]. …”

Section: Methodsmentioning

confidence: 99%

Delayed Cerebrovascular Autoregulatory Response to Ergometer Exercise in Normotensive Elderly Humans

Heckmann

Brown²,

Cheregi³

et al. 2003

Cerebrovasc Dis

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“…It is unclear whether this device reduces blood gas testing (and thus cost) during the apnea test. 28,29 Conclusion. Apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing.…”

Section: Analysis Of Evidencementioning

confidence: 98%

Evidence-based guideline update: Determining brain death in adults

Wijdicks¹,

Varelas²,

Gronseth³

et al. 2010

Neurology

917

775

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Objective:To provide an update of the 1995 American Academy of Neurology guideline with regard to the following questions: Are there patients who fulfill the clinical criteria of brain death who recover neurologic function? What is an adequate observation period to ensure that cessation of neurologic function is permanent? Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? What is the comparative safety of techniques for determining apnea? Are there new ancillary tests that accurately identify patients with brain death?Methods: A systematic literature search was conducted and included a review of MEDLINE and EMBASE from January 1996 to May 2009. Studies were limited to adults (aged 18 years and older). Results and recommendations:In adults, there are no published reports of recovery of neurologic function after a diagnosis of brain death using the criteria reviewed in the 1995 American Academy of Neurology practice parameter. Complex-spontaneous motor movements and falsepositive triggering of the ventilator may occur in patients who are brain dead. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly. Apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing. There is insufficient evidence to determine if newer ancillary tests accurately confirm the cessation of function of the entire brain. Neurology

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“…In order to avoid repeated arterial blood gas testing, continuous intra-arterial and transcutaneous blood gas measuring were compared with in vitro arterial blood gas analysis during apnea testing. There were several technical difficulties and no clear advantages, so that neither procedure could replace the standard method of arterial blood gas testing [57].…”

Section: Apnea Testingmentioning

confidence: 99%

Pitfalls in the Diagnosis of Brain Death

Busl

Greer

2009

Neurocrit Care

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Since the establishment of the concept of declaring death by brain criteria, a large extent of variability in the determination of brain death has been reported. There are no standardized practical guidelines, and major differences exist in the requirements for the declaration of brain death throughout the USA and internationally. The American Academy of Neurology published evidence-based practice parameters for the determination of brain death in adults in 1995, requiring the irreversible absence of clinical brain function with the cardinal features of coma, absent brainstem reflexes, and apnea, as well as the exclusion of reversible confounders. Ancillary tests are recommended in cases of uncertainty of the clinical diagnosis. Every step in the determination of brain death bears potential pitfalls which can lead to errors in the diagnosis of brain death. These pitfalls are presented here, and possible solutions identified. Suggestions are made for improvement in the standardization of the declaration of brain death.

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Transcutaneous and intra-arterial blood gas monitoring???a comparison during apnoea testing for the determination of brain death

Cited by 12 publications

References 19 publications

Delayed Cerebrovascular Autoregulatory Response to Ergometer Exercise in Normotensive Elderly Humans

Delayed Cerebrovascular Autoregulatory Response to Ergometer Exercise in Normotensive Elderly Humans

Evidence-based guideline update: Determining brain death in adults

Pitfalls in the Diagnosis of Brain Death

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