Apnea Testing for the Determination of Brain Death: A Systematic Scoping Review

An Update on Brain Death/Death by Neurologic Criteria since the World Brain Death Project

The World Brain Death Project (WBDP) is a 2020 international consensus statement that provides historical background and recommendations on brain death/death by neurologic criteria (BD/DNC) determination. It addresses 13 topics including: (1) worldwide variance in BD/DNC, (2) the science of BD/DNC, (3) the concept of BD/DNC, (4) minimum clinical criteria for BD/DNC determination, (5) beyond minimum clinical BD/DNC determination, (6) pediatric and neonatal BD/DNC determination, (7) BD/DNC determination in patients on ECMO, (8) BD/DNC determination after treatment with targeted temperature management, (9) BD/DNC documentation, (10) qualification for and education on BD/DNC determination, (11) somatic support after BD/DNC for organ donation and other special circumstances, (12) religion and BD/DNC: managing requests to forego a BD/DNC evaluation or continue somatic support after BD/DNC, and (13) BD/DNC and the law. This review summarizes the WBDP content on each of these topics and highlights relevant work published from 2020 to 2023, including both the 192 citing publications and other publications on BD/DNC. Finally, it reviews questions for future research related to BD/DNC and emphasizes the need for national efforts to ensure the minimum standards for BD/DNC determination described in the WBDP are included in national BD/DNC guidelines and due consideration is given to the recommendations about social and legal aspects of BD/DNC determination.

Apnea Testing Practice to Increase Baseline PaCO2 and Frequency of Blood Gas Analyses

OBJECTIVE

To study the influence of the initial partial pressure of carbon dioxide (PaCO2) and frequency of blood gas analyses on the positivity rate and safety of apnea testing (AT).

DESIGN

A prospective multicenter cohort study.

SETTING

Seven teaching hospitals.

PARTICIPANTS

A total of 55 patients who underwent AT.

INTERVENTIONS

Patients were divided into 2 groups according to their initial PaCO2-the experimental group (≥40 mmHg, 27 patients) and the control group (<40 mmHg, 28 patients). Blood gas analysis was performed at 3, 5, and 8 minutes, and vital signs were taken. AT results and complications were compared between the groups.

RESULTS

The initial PaCO2 of the experimental group was 42.8 ± 2.2 mmHg v 36.4 ± 2.9 mmHg in the controls. The AT positivity rate was 100%. The experimental group needed less time to reach the target PaCO2 than the control group (4.07 ± 1.27 minutes v 5.68 ± 2.06 minutes; p = 0.001). Twenty-six patients (96.3%) in the experimental group reached the target PaCO2 in 5 minutes v 17 in the control group (60.7%) (p = 0.001). Seven patients (12.7%) were unable to complete 8-minute disconnection due to hypotension. The experimental group had a slightly lower incidence of hypotension than the control group, but there was no statistical difference (7.4% v 17.9%, p = 0.245).

CONCLUSION

Increasing the baseline PaCO2 and doing more blood gas analyses can significantly shorten the time needed for AT and improve the AT positivity rate.

The 2023 American Academy of Neurology, American Academy of Pediatrics, Child Neurology Society, and Society of Critical Care Medicine Pediatric and Adult Brain Death/Death by Neurologic Criteria Determination Consensus Guidelines: What the Critical Care Team Needs to Know

Guidelines for brain death/death by neurologic criteria (BD/DNC) determination were revised to provide a consistent and updated approach to BD/DNC evaluation across all ages by the American Academy of Neurology, American Academy of Pediatrics, Child Neurology Society, and Society of Critical Care Medicine. This article is intended to complement the guidelines and highlight aspects relevant to the critical care community; the actual guidelines should be used to update hospital protocols and dictate clinical practice. Because BD/DNC evaluations are conducted in the ICU, it is essential for members of the critical care community to familiarize themselves with these guidelines. The fundamental concept of BD/DNC has not changed; BD/DNC is permanent loss of function of the brain as a whole, including the brain stem, resulting in coma, brainstem areflexia, and apnea in the setting of an adequate stimulus. The BD/DNC evaluation requires a sufficient observation period to ensure there is no chance of recovery, followed by exclusion of potentially confounding conditions like hypothermia, hypotension, severe metabolic disturbances, or medication effects. Specific guidance is provided for patients who were treated with therapeutic hypothermia or medical or surgical interventions to manage intracranial hypertension. The guidelines outline a structured and meticulous neurologic examination and detail the responses consistent with BD/DNC. A protocol is provided for how to safely perform apnea testing, including modifications needed for patients on extracorporeal membrane oxygenation. Controversial issues such as consent, BD/DNC evaluation in pregnancy, preservation of neuroendocrine function, and primary posterior fossa injuries are addressed. The ultimate goal is to ensure a consistent and accurate approach to BD/DNC evaluation in patients of all ages, fostering public trust in the medical community's ability to determine death. By adhering to these guidelines, critical care clinicians can confidently navigate the challenging aspects of BD/DNC determination.

Improvement Gaps to Deal with the Shortage of Lungs for Transplant From a Middle Income Country's Perspective

OBJECTIVES

Our study aimed to identify the potential causes for the low lung procurement rate in Argentina and to develop strategies to the actual problems in donor management focused on lung retrieval.

MATERIALS AND METHODS

We performed a crosssectional study in which we analyzed data obtained from digital self-reported surveys conducted on professionals participating in the organ procurement process in Argentina. The surveys included questions on donor management, selection criteria, and resource availability involving increasing lung procurement.

RESULTS

Among professionals surveyed, 23.7% did not use advanced hemodynamic monitoring in their donor maintenance and limited their use to central venous pressure. Only 35.8% of participants considered maintaining central venous pressure <10 mm Hg during donor maintenance. With regard to donors with severe deterioration of the ejection fraction, 47.4% of participants would not use restrictive fluid, and only 23.2% would use an advanced monitoring of the hemodynamic status to guide fluid management. Only 27.8% of participants routinely would use steroids to improve lung function in donors. With regard to mechanical ventilation, 80.4% of participants used protective ventilation, but only 4.10% used it adequately. Recruitment maneuvers were routinely used by only 3.1% of those surveyed. With regard to expanded selection criteria (age >55 years, smoking habit of >20 packs/year, positive upper airway cultures, unspecific infiltrates in radiography, and >72 hours of mechanical ventilation), 92.8% of surveyed participants would discount patients with some of these expanded selection criteria without considering offering the lungs for donation.

CONCLUSIONS

Opportunities for improvement may involve training physicians involved in the donor maintenance process and reviewing the donor selection criteria used to increase adherence to expanded selection criteria.

Pediatric and Adult Brain Death/Death by Neurologic Criteria Consensus Guideline

BACKGROUND AND OBJECTIVES

The purpose of this guideline is to update the 2010 American Academy of Neurology (AAN) brain death/death by neurologic criteria (BD/DNC) guideline for adults and the 2011 American Academy of Pediatrics, Child Neurology Society, and Society of Critical Care Medicine guideline for infants and children and to clarify the BD/DNC determination process by integrating guidance for adults and children into a single guideline. Updates in this guideline include guidance related to conducting the BD/DNC evaluation in the context of extracorporeal membrane oxygenation, targeted temperature management, and primary infratentorial injury.

METHODS

A panel of experts from multiple medical societies developed BD/DNC recommendations. Because of the lack of high-quality evidence on the subject, a novel, evidence-informed formal consensus process was used. This process relied on the panel experts' review and detailed knowledge of the literature surrounding BD/DNC to guide the development of preliminary recommendations. Recommendations were formulated and voted on, using a modified Delphi process, according to the 2017 AAN Clinical Practice Guideline Process Manual.

MAJOR RECOMMENDATIONS

Eighty-five recommendations were developed on the following: (1) general principles for the BD/DNC evaluation, (2) qualifications to perform BD/DNC evaluations, (3) prerequisites for BD/DNC determination, (4) components of the BD/DNC neurologic examination, (5) apnea testing as part of the BD/DNC evaluation, (6) ancillary testing as part of the BD/DNC evaluation, and (7) special considerations for BD/DNC determination.

Consent for determination of death by neurologic criteria in Canada: an analysis of legal and ethical authorities, and consensus-based working group recommendations

This article addresses the following question: should physicians obtain consent from the patient (through an advance directive) or their surrogate decision-maker to perform the assessments, evaluations, or tests necessary to determine whether death has occurred according to neurologic criteria? While legal bodies have not yet provided a definitive answer, significant legal and ethical authority holds that clinicians are not required to obtain family consent before making a death determination by neurologic criteria. There is a near consensus among available professional guidelines, statutes, and court decisions. Moreover, prevailing practice does not require consent to test for brain death. While arguments for requiring consent have some validity, proponents cannot surmount weightier considerations against imposing a consent requirement. Nevertheless, even though clinicians and hospitals may not be legally required to obtain consent, they should still notify families about their intent to determine death by neurologic criteria and offer temporary reasonable accommodations when feasible. This article was developed with the legal/ethics working group of the project, A Brain-Based Definition of Death and Criteria for its Determination After Arrest of Circulation or Neurologic Function in Canada developed in collaboration with the Canadian Critical Care Society, Canadian Blood Services, and the Canadian Medical Association. The article is meant to provide support and context for this project and is not intended to specifically advise physicians on legal risk, which in any event is likely jurisdiction dependent because of provincial or territorial variation in the laws. The article first reviews and analyzes ethical and legal authorities. It then offers consensus-based recommendations regarding consent for determination of death by neurologic criteria in Canada.

Quality improvement in the determination of death by neurologic criteria around the world

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2023. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2023 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

Optimal duration of the apnea test for determining brain death: Benefit of the short-term apnea test

Background

The criteria for brain death determination have not been unified globally, and there is no global consensus on the apnea test, which is essential for determining brain death. Since the apnea test is associated with many complications, we aimed to determine an optimal duration of the apnea test.

Methods

We analyzed the results of the apnea test performed for brain death determination between August 2013 and February 2021 at a single institution in South Korea. Elevations in the partial pressure of carbon dioxide and mean arterial blood pressure fluctuations over time in the apnea test were recorded.

Results

In the 1^st and 2^nd tests, the mean partial pressure of carbon dioxide increased by more than 20 mmHg at 3 min after the apnea test compared to before the test (P < 0.05). At 4 min in the 1^st test and 5 min in the 2^nd test, the partial pressure of carbon dioxide exceeded 60 mmHg (P < 0.05). The fluctuation in the mean arterial blood pressure observed for 5 min during the apnea test was not significant. There was no significant fluctuation in the mean arterial blood pressure over time in the apnea test between patients with normal chest radiography findings and those with abnormal chest radiography findings (P = 0.888).

Conclusions

Our study proposes that a short-term apnea test protocol is valid for the preservation of organs for donation.

The practical role of the respiratory therapist in the standard apnea test procedure for declaration of death via neurologic criteria in adults

Introduction

Respiratory therapists (RTs) in the intensive care unit can at times find themselves involved in and assisting during the performance of the apnea test (ApT). The ApT is a clinically complex procedure and is the last part of the clinical declaration of death by neurologic criteria (DNC) protocol and requires close collaboration between the physicians and the RTs. As such, the ApT should be performed with the upmost attention to detail.

Context and Aims

The RTs need to be versed on the intricacies of the ApT. Except in very large medical centers, the ApT is not a procedure performed with high enough frequency as to maintain high level of proficiency. For a successful ApT, structured knowledge and preparation are paramount. This publication attempts to fill that gap, for adult hospitalized patients not on ECMO (extracorporeal membrane oxygenation). To generate this report, we make use of the published guidelines, and our personal experience on performing ApTs in large medical centers.

Conclusion

We provide a structure by means of a checklist, from the RTs’ perspective, to guide and help them lead on the efficient performance of the ApT.

Minimum Criteria for Brain Death Determination: Consensus Promotion and Chinese Practice

BACKGROUND

Brain death (BD), the irreversible cessation of function in the whole brain, is a well-known condition in most countries. The criteria and practical guidelines for brain death determination (BDD) in China were issued by the Brain Injury Evaluation Quality Control Center (BQCC) of the National Health and Family Planning Commission in 2013. Thereafter, we proposed a plan called the three-step quality control plan (three-step QCP) to ensure the safety and consistency of the clinical judgments regarding BD. By retrospectively reviewing this plan, we aimed to identify problems during its implementation and to provide suggestions for future work on quality control for BDD.

METHODS

Data were retrieved from the BQCC database. The characteristics and test results of physicians undergoing a BDD training course and the BD case records submitted by hospitals before and after receiving accreditation were analyzed.

RESULTS

In the first step of the plan, the error rate for physicians undergoing the BDD paper test was highest for limb movement discrimination (26.29%); this error rate was correlated with age (per 10-year increase) (odds ratio = 1.262, 95% confidence interval 1.067-1.491, P = 0.007) but was nonsignificantly associated with sex, specialty category, professional level, and hospital level (P > 0.05). During the second step of the plan, the highest percentage of problems was associated with apnea testing (22.75%), followed by ancillary testing of BDD (16.17%). In the last step, the highest percentage of problems in the case records was associated with apnea testing (41.73%).

CONCLUSIONS

The three-step QCP is of significant utility for ensuring accuracy and appropriateness in BDD. Simultaneously, this study provides important evidence for advancing quality control for BDD in the next stage.

Safety and reliability of artificial CO2 augmentation method in comparison with standard apneic oxygenation method for brain death determination

INTRODUCTION

The most commonly used apnea test for determination of brain death is the apneic oxygenation method. While all the commonly used apnea tests have associated complications, artificial CO2 augmentation has been reported to have fewer complications. However, data supporting the use of the latter method is limited.

METHODS

We identified 102 patients who underwent brain death testing during the last ten years. Artificial CO2 augmentation apnea testing was used in 50 of these patients while 52 patients underwent standard apneic oxygenation apnea testing.

RESULTS

No significant differences between the two groups were noted in any previously considered clinical outcomes, including hypoxemia, acidemia, or shock. However, shorter duration of apnea testing was observed in the artificial CO2 augmentation method suggesting its feasibility to the standard apneic oxygenation method in terms of convenience and reduction of the risk surrounding prolonged hypercapnia and hypoxemia.

CONCLUSION

This retrospective cohort study provides further observational evidence to support the safety of alternate apnea testing techniques with the standard apnea method for determination of brain death in adults.

Apnea Test on Extracorporeal Membrane Oxygenation: Step Forward with Carbon Dioxide

Apnea test must be performed to confirm brain death in patients meet clinical criteria. But the increment of carbon dioxide is generally not achievable because of the diminished production of carbon dioxide and additional sweep in extra corporeal membrane oxygenation (ECMO). We report three children with congenital heart disease treated with ECMO and had brain death during follow-up. All met clinical criteria but apnea test cannot be achieved in classical way because of prolonged duration and hemodynamic compromise. Therefore, we used external carbon dioxide to achieve desired levels of oxygen and carbon dioxide safely. Because of the lack of protocols for pediatric patients on ECMO, apnea test with exogenous carbon dioxide may be a reliable and rapid test in such patients. Especially cardiac patients, in whom classical apnea test can cause rapid deterioration, exogenous carbon dioxide may serve as an alternative.

Bilateral Pneumothoraces in a 3-Month-Old Infant During an Apnea Test in the Diagnosis of Brain Death

We present the case of a 3-month-old boy who suffered bilateral pneumothoraces secondary to insufflation of oxygen into the endotracheal tube during the apnea test as part of brain death testing. Although rare, awareness of this potential complication of the apnea test is of particular importance in pediatric patients who have narrow endotracheal tubes because resistance to expiratory flow increases exponentially as lumen diameter decreases.