Brain death investigation – survey of physicians in the Czech Republic

Summary

Aim: This article explores brain death assessment according to neurological criteria and evaluates a nationwide survey on diagnostic procedures. It also examines awareness among healthcare professionals. Methods: An online survey was conducted from January 7 to March 3, 2025, targeting 115 healthcare facilities. The questionnaire collected demographic data, specialties, and frequency of brain death assessments and examination of individual reflexes. Results: 523 respondents participated in the questionnaire survey, with 38% having experience in brain death assessment. A total of 187 physicians regularly examine brain death, with 74% of them performing fewer than five examinations per year. The most common specialists were anesthesiologists (48%) and neurologists (27%). Most physicians (50%) follow the IKEM “Život²” manual. The main reason for the examination (61%) was the donor program. The apnea test is performed by 81% of respondents, 90% of them only after a clinical examination. The most commonly used confirmatory method is CTA (26%), while 43% of physicians indicate confirmatory testing only in the case of a donor program. Conclusion: A questionnaire survey revealed the existence of interindividual differences in the investigative procedure for clinical determination of brain death in the Czech Republic. The consistency of clinical examinations is insufficient in patients referred to the donor program. In contrast, the apnea test is unnecessarily overused in examinations conducted as part of the decision-making process regarding futile care limitations. The findings emphasize the need for enhanced education on brain death assessment, particularly those who rarely encounter this diagnosis. It is also crucial to understand the concept of brain death and how it is communicated both among healthcare professionals and to the public.

Keywords:

brain death – diagnosis – neurological criteria – donor program – brain-stem refl exes

This is an unauthorised machine translation into English made using the DeepL Translate Pro translator. The editors do not guarantee that the content of the article corresponds fully to the original language version.

Funding:

This study was supported by the General University Hospital in Prague project MH CZ‑RVO‑VFN64165 and by the Research Program of Charles University: Cooperatio Neuroscience.

Introduction

Brain death/death by neurologic criteria (BD/DNC) is declared when there is irreversible loss of all brain functions, including the brainstem, secondary to catastrophic brain damage [1]. This condition is characterized by deep coma, brainstem areflexia, and loss of spontaneous respiration in response to adequate stimuli [2, 3]. In some countries attention is limited to loss of brainstem function alone [4, 5]. The clinical examination focuses on brainstem function.

The diagnosis of BD/DNC is usually based on clinical examination [2]. Protocol-driven diagnostic workup is associated with the organ donor program. Legal standards require fulfillment of certain conditions, such as confirmed catastrophic brain lesion and appropriate imaging. Before examination, body temperature and blood pressure must be stabilized, the effects of drugs eliminated, and acid–base disturbances corrected (Act No. 285/2002 Coll. –⁠ Transplantation Act [6]). Current recommendations require waiting at least five elimination half-lives of the sedative after its discontinuation before performing the clinical examination [1].

The clinical examination itself comprises assessment of level of consciousness, brainstem reflexes, and the apnea test. A confirmatory examination (CE) refers to use of an instrumental method such as digital subtraction angiography, CT angiography, transcranial color-coded Doppler, brainstem auditory evoked potentials, or brain perfusion scintigraphy [7]. In cases of devastating infratentorial lesions, a CE is not required.

In the Czech Republic, the diagnosis of BD/DNC must be made by at least two physicians with the appropriate specialization (§10 (2) of the Transplantation Act [6]) acting independently. For an adult patient, at least one of the physicians must be specialized in anesthesiology, intensive care medicine, neurology, or neurosurgery. Death is declared upon completion of all required examinations by the second physician.

Legislation defines the scope of examination only by enumeration. Unlike a standard neurological examination, the determination of BD/DNC does not allow for false-positive results. However, there is currently no nationally standardized methodology in the Czech Republic for the clinical examination to determine BD/DNC, including the prerequisites under which the examination may be performed. It is known that even in countries where a methodology for conducting the clinical examination for BD/DNC exists, inconsistencies in clinical examination procedures persist [2].

The aim of this study was to obtain an overview of clinical procedures for determining BD/DNC and to identify whether inconsistencies exist in examination practices.

 

Methods:

The survey was conducted via an online questionnaire using Google Forms. The selection of questions was based on methodologies from previously published international studies [8–10] and on questions formulated by the authors (reason for testing, duration of the washout period after stopping sedative medication, etc.). A request to distribute the questionnaire link to all physicians at each institution with a relevant specialty was sent to 115 inpatient healthcare facilities. Distribution proceeded in three phases. In the first phase, facility managements were contacted according to the list of the National Register of Health Service Providers (https://nrpzs.uzis.cz). In the second phase, department heads at a total of 13 healthcare facilities were contacted; based on the scope of their activities and the presence of physicians with specialist qualifications, these centers were expected to have a higher expected number of potential organ donors. The third phase involved contacting the presidents of specialty societies of the Czech Medical Society of Jan Evangelista Purkyně (the Czech Society of Anesthesiology, Resuscitation and Intensive Care; the Czech Society of Intensive Care Medicine; the Czech Neurological Society; the Czech Neurosurgical Society; the Czech Pediatric Society; and the Czech Neonatal Society). The survey was conducted from 7/1/2025 to 3/3/2025. The study was carried out in accordance with the Declaration of Helsinki (1975) and its revisions (2004 and 2008). Due to the anonymity of the questionnaire survey, the study did not require approval by an ethics committee.

The questions were divided into sections. Demographics collected age, years since graduation, and sex. Respondents were asked about specialty, type of institution, and bed profile. The key question was whether they perform clinical determination of brain death; respondents who answered “no” were directed to end the questionnaire. Further questions addressed which information sources they use for BD/DNC assessment, whether brain imaging is required, how long after stopping sedation they perform the examination, and how frequently they assess brain death in adults and in children.

The questionnaire also assessed the frequency of examination of individual reflexes and tests, such as the apnea test, and the frequency of indications for specific CE. Respondents provided a subjective evaluation of their practice (qualified estimate). Answer options ranged from “always” to “do not perform.” The individual questions are presented in the Results section.

Results are reported as frequencies of responses. The Shapiro–Wilk test was used to assess normality. Data with a normal distribution are presented as mean ± standard deviation; non-normally distributed data are presented as median and interquartile range. To determine the significance of differences in performance of individual clinical tests between physician groups (stratified by the reason for performing BD/DNC assessment), the chi‑square test was used with a significance level of were 0.01. To refine estimates, confidence intervals calculated for the proportions of individual modalities of clinical and confirmatory testing. Calculations were performed using STATISTICA 12.0 software (Palo Alto, CA, USA) [11].

 

Results

Survey Distribution

First phase: Of 115 inpatient healthcare facilities contacted, further distribution of the questionnaire was confirmed by 5 management offices (2 district hospitals and 3 regional hospitals); 3 managements actively refused distribution (1 university hospital and 2 district hospitals); no response was received from the remainder. In the second phase, a total of 95 department heads and chiefs from 13 hospitals were contacted (7 universities, 2 regionals, and 4 districts). Active consent to further distribution was received from 24 of these (25%) (nine anesthesiology and intensive care unit, 4 neurology, 1 neurosurgery). No active refusals were recorded. The remaining 71 departments did not respond. During the first two phases of the survey, which lasted from 1/7/2025 to 1/18/2025 (12 days), 394 respondents replied (75% of total responses). Third phase: Three society presidents actively confirmed distribution to all physician members of their specialty societies (Czech Society of Anesthesiology, Resuscitation and Intensive Medicine; Czech Neurological Society; Czech Neurosurgical Society). Two presidents refused and one did not respond. The reported numbers of physician members to whom the questionnaire was distributed at the time of distribution were 1,185; 1,089; and 251, respectively –⁠ a total of 2,525 registered members.

 

Respondents composition

The survey included 523 respondents (219 women; age 42.8 ± 12.0 years). Of these, 38.0% of physicians had experience with brain death assessment. Brain death is assessed regularly in adults by 187 respondents and in children by 17 (the latter were not included in further analyses). Thus, the total number of analyzed respondents was 187 (56 women; age 44.9 ± 10.4 years; mean time since graduation 19.9 ± 11.0 years). In terms of frequency, 138 physicians (74%) perform brain death assessments fewer than five times per year; only 6 (3%) perform them more than 20 times per year (4 anesthesiologists and 2 neurologists). The total number of respondents in this survey comprised approximately 20% of physicians registered in the specialty societies.

 

Answers to the questions:

Question: Which specialist qualification in the Czech Republic performs brain death assessment most often?

Brain death is most frequently assessed by physicians specialized in anesthesiology and intensive care medicine (48%), followed by neurologists (27%), intensive care medicine (11%), neurosurgery (4%), cardiology (5%), and 5% of physicians had no specialist qualification. Fourteen percent of respondents had more than one specialty (Figure 1B).

 

Question: How often is brain death assessed depending on the type of healthcare facility?

More than half of assessments take place in university hospitals; the remainder are divided roughly equally between regional and district hospitals (Figure 1A). This distribution is primarily driven by the responding centers.

 

Question: According to which protocol do respondents perform brain death assessment? The largest group (93; 50%) follow the IKEM “Život²” web form or printed manual. Seventy-five (40%) follow their institution’s internal regulation, 31 (17%) use their own procedure, and 9 (5%) follow information from the internet. Twenty-four (13%) use multiple sources.

 

Question: What are the reasons for performing brain death determination under the legislation? For 115 respondents (61%) the reason is solely the donor program; 7 (4%) cited withdrawal of futile therapy; and 65 (35%) perform assessments for both reasons (comparison of procedures shown in Table 1).Question: How often do you require initial brain imaging?

Seventy-four physicians (40%) always perform imaging; conversely, 36 respondents (19%) usually do not perform imaging (in <50% of cases); 13 physicians (9%) never perform imaging.

 

Question: What prompts you to start a brain death assessment?

A severe structural finding on CT or MRI prompted 151 physicians (81%); 125 (67%) cited post‑resuscitation patients who do not regain consciousness; 92 (49%) cited poor prognosis; and 77 (41%) cited limitation of care. A request for a consultative assessment was reported by 68 physicians (36%).

 

Question: How long after stopping sedation does the physician proceed to clinical examination?

Responses to this question are presented in Table 1.

 

Question: What percentage of physicians and which specialties do not routinely perform each part of the clinical examination, the apnea test, and CE, and how does scope depend on the physician’s specialty?

The most performed clinical test is the apnea test, performed by 81% of respondents (95% CI [0.74, 0.86]), while 2% never perform it (95% CI [0.00, 0.05]). The least frequently performed elements are nociceptive response to stimulation of all four limbs (57%, 95% CI [0.50, 0.64]) and the oculovestibular reflex (59%, 95% CI [0.52, 0.66]); summary frequencies are shown in Table 3. Seven physicians reported performing a complete neurological examination; seven perform the oculocardiac reflex; and five routinely perform an atropine test. Among physicians who did not “always” perform the apnea test, there were 36 (19%) physicians, including 15 anesthesiologists and 11 neurologists, and 7 physicians without the requisite specialty qualification.

 

Question: How often is the apnea test performed only after the clinical examination?

Five respondents (3%) reported that they do not perform the apnea test at all, and 17 physicians (9%) perform it only sometimes; 168 respondents (90%) perform the apnea test after completing the clinical examination. During the apnea test, 101 physicians (54%) base their assessment only on rising PaCO2, 16 physicians (9%) on desaturation, and 70 (37%) on both parameters.

 

Question: What are the most frequently used CE?

The most frequently used method was CTA, which 48 physicians (26%) always use. Four physicians (2%) do not perform any CE. Other tests reported included EEG by 5 physicians (3%). Transcranial color-coded sonography (TCCS) is used most often by neurologists (11 physicians –⁠ 50% of respondents who indicate this test). Summary data are in Table 4.

 

Question: How often is a CE indicated only after clinical criteria for brain death are met?

Only in the donor program did 81 physicians (43%) indicate CE; 73 respondents (39%) did not indicate CE in cases of devastating infratentorial injury, and the same number indicated testing only after the apnea test; 5 respondents (3%) never indicated CE.

 

Discussion:

This article provides an overview of variability in diagnostic procedures for determining BD/DNC. It includes a national survey of practices for BD/DNC assessment and a review of healthcare professionals’ knowledge about brain death and its examination.

 

Which specialist most often assesses brain death in the Czech Republic?

Most respondents were specialists in anesthesiology and intensive care medicine or in neurology. Nearly 10% of respondents reported performing BD/DNC assessments without the corresponding specialist qualification. Legislation requires that the diagnosis of brain death for the donation purposes be made by at least two independent physicians, at least one of whom holds the required specialty qualification (§ 10 (2) of Act No. 285/2002 Coll. [6]). Physicians without formal specialty may be supervised by a qualified physician, which is important for training. However, there is no dedicated educational material in the Czech Republic addressing the neurological examination for determination of brain death. For example, a 2019 US survey [12] found that only 76% of physicians had training in performing the examination and only 25% performed it in accordance with guidelines.

 

How often is brain death assessed depending on facility type?

A study of 600 hospitals [9] revealed variability in BD/DNC criteria compared with the American Academy of Neurology guidelines. The greatest differences concerned exclusion criteria and specific testing methods. Assessments often involve critically ill patients. A prospective study of 792 patients with GCS < 8 found 120 cases (15%) with clinical BD/DNC diagnosis [13]. The number of transplant coordinators was positively associated with numbers of brain-dead patients [9]. In our sample, most BD/DNC determinations occurred in university hospitals (54%).

 

What is the most common reason for full BD/DNC assessment?

The primary reason for BD/DNC determination is the donor program, which requires formal confirmation of the clinical diagnosis. Although other scenarios (e.g., withdrawal of futile therapy) may not require BD/DNC confirmation, correct performance and interpretation of the examination remain essential. In our survey, 61% of respondents indicated the donor program as the reason for BD/DNC assessment. Data shows that when BD/DNC assessment is performed for donor program purposes, the scope of brainstem reflex testing and frequency of apnea testing are greater than when assessments are performed for withdrawal of futile therapy. Czech law lists the clinical tests that a properly qualified physician must perform but does not legislatively specify their methodology. The mandated procedure applies primarily to potential donors, where instrumental confirmatory testing is also legally required. When considering limitation of futile care, inconsistency and interindividual variability in performed examinations are acceptable and depend on the examining physician or clinician consensus on interpretation. No formal recommendation currently exists for these cases; interdisciplinary consultation, including a physician experienced in palliative medicine is advisable. Thus, the examining physician bears responsibility for deciding the adequate scope of examination in each clinical situation. Established BD/DNC protocols can only serve as support for further decision-making. Most physicians (81%) initiate BD/DNC assessment for severe structural lesions on CT/MRI, and 50% assess BD/DNC when a post‑resuscitation patient fails to regain consciousness. A survey of 195 clinicians and nurses [8] involved in organ donation decisions found that only 35% correctly identified legal and medical criteria for death determination. Interventional studies [14] showed that 65% of healthcare workers agreed that loss of consciousness and loss of breathing is sufficient to define death. A Singaporean survey [10] revealed variability in test performance and the need for more detailed guidance.

Concerns and public understanding of brain death

Concerns about test validity and diagnostic variability have been studied [15]. Czech legislation anchors the examination firmly. A Singapore public survey [16] showed persistent resistance to the concept of brain death, with many respondents favoring circulatory death as a clearer indicator, which affects willingness to donate. A cross‑sectional study assessing public information analyzed the top ten Google websites and top ten YouTube videos [17]. Inaccuracies contrary to national guidelines were present on 4/10 websites and 6/10 videos, and in 80% of YouTube comments. Websites mentioned organ donation in 90% of cases; videos were often emotional (78%), with 33% containing negative comments about physicians and 50% referencing organ donation.

 

Which specialties and what percentages do not routinely perform each part of the clinical exam, the apnea test, and confirmatory tests, and how does scope depend on specialty?

BD/DNC is a clinical diagnosis that must not be subject to false-positive errors. The apnea test and confirmatory testing are especially relevant when considering organ donation. Exceptions occur when complete clinical examination is impossible (e.g., devastating facial trauma). Survey results show that performance of individual tests depends on the assessment reason, with donor-program assessments yielding higher test frequencies.

 

How often is the apnea test performed after clinical examination?

The apnea test is mandatory for BD/DNC determination. Only 81% of respondents always perform it and 2% never do it. Possible explanations include that another physician may perform the apnea test. A high proportion of apnea testing (71%) occurs outside the donor program (see Table 1). When deciding on limitation of futile care, there is no recommendation to perform every single subtest (including the apnea test). Decisions about limiting care should be based on the overall poor prognosis or advance directives. In one study, 10% of physicians did not perform the apnea test and 28% performed confirmatory testing if the patient was spontaneously breathing during the test [12]. Significant variability was also observed in the Singapore study, where only 14% of physicians could correctly describe apnea-test performance [10].

 

The issue of the absence of sedation effects

The interval from stopping sedation to clinical examination showed wide variability. In 27% of cases the interval after propofol was too short; with fentanyl, examinations were pharmacologically affected in 78% (see Table 2). Such influence can lead to false-positive results and incorrect decisions.

 

Limitations of this study

The limitation of this study is uneven respondent distribution, reflecting incomplete participation. Although hospital administrations were contacted to reach all physicians, response during the first 10 days was modest (294 respondents), suggesting the questionnaire may not have reached target physicians or they were unwilling to participate. After contacting specialty societies, respondents increased to 523. Results cannot be generalized to all Czech physicians. The aim was to identify whether inconsistencies in BD/DNC practice exist in the Czech Republic, not to perform a nationwide prevalence study. Because BD/DNC determination is a delicate issue, any deviation from methodological standards may raise clinical and legal doubts. No national standard currently exists in the Czech Republic; international guidelines [2] may inform local recommendations. Identified discrepancies signal the need for mandatory national protocols. Another argument for guidance is that physicians from specialties other than neurology are authorized to perform BD/DNC examinations; these specialists urgently need educational support and certification of their skills.

 

Conclusion

This study provided insights into BD/DNC assessment and demonstrated the need for more detailed education of physicians who encounter this diagnosis, especially those who do so infrequently. Variability in the scope and conditions for conducting the clinical examination is evident. Survey results align with findings from other countries. A unified, mandatory methodology and defined scope of the clinical examination would increase the reliability of clinical conclusions for the donor program. Conditions may be somewhat more flexible when making decisions about limitations or withdrawal of futile care; nonetheless, in both contexts a correct and uniform methodology for individual clinical tests is critically important.

 

Conflict of interest: None of the authors has any conflict of interest related to this article.

 

 

 

 

 

 

 

 

 

 

References

1. Greer DM, Kirschen MP, Lewis A, et al., Pediatric and Adult Brain Death/Death by Neurologic Criteria Consensus Guideline. Neurology, 2023. 101(24): p. 1112-1132.

2. Greer DM, Shemie SD, Lewis A, et al., Determination of Brain Death/Death by Neurologic Criteria: The World Brain Death Project. JAMA, 2020. 324(11): p. 1078-1097.

3. Shemie SD, Doig C, Dickens B, et al., Severe brain injury to neurological determination of death: Canadian forum recommendations. CMAJ, 2006. 174(6): p. S1-13.

4. Wijdicks EF, The transatlantic divide over brain death determination and the debate. Brain, 2012. 135(Pt 4): p. 1321-31.

5. Wijdicks EF, Brain death worldwide: accepted fact but no global consensus in diagnostic criteria. Neurology, 2002. 58(1): p. 20-5.

6. Act No. 285/2002 Coll., on the Donation, Removal and Transplantation of Tissues and Organs and on Amendments to Certain Acts (Transplantation Act), Czech Republic, Collection of Laws 2002, p. 4734.

7. Ostrý S, Holečková I, Sivák Š, et al., Ancillary electrophysiological examination in determination of brain death. Neurol Praxi, 2025. 26(2): p. 117-121.

8. Youngner SJ, Landefeld CS, Coulton CJ, et al., `Brain Death' and Organ Retrieval: A Cross-sectional Survey of Knowledge and Concepts Among Health Professionals. JAMA, 1989. 261(15): p. 2205-2210.

9. Powner DJ, Hernandez M, Rives TE, Variability among hospital policies for determining brain death in adults. Crit Care Med, 2004. 32(6): p. 1284-8.

10. Chin KJ, Kwek TK, Lew TW, A survey of brain death certification--an impetus for standardisation and improvement. Ann Acad Med Singap, 2007. 36(12): p. 987-94.

11. STATISTICA, version 12.0. 2013, TIBCO Software Inc.: Palo Alto, CA.

12. Braksick SA, Robinson CP, Gronseth GS, et al., Variability in reported physician practices for brain death determination. Neurology, 2019. 92(9): p. e888-e894.

13. Senouci K, Guerrini P, Diene E, et al., A survey on patients admitted in severe coma: implications for brain death identification and organ donation. Intensive Care Med, 2004. 30(1): p. 38-44.

14. Chatterjee K, Rady MY, Verheijde JL, et al., A Framework for Revisiting Brain Death: Evaluating Awareness and Attitudes Toward the Neuroscientific and Ethical Debate Around the American Academy of Neurology Brain Death Criteria. J Intensive Care Med, 2021. 36(10): p. 1149-1166.

15. Nikas NT, Bordlee DC, Moreira M, Determination of Death and the Dead Donor Rule: A Survey of the Current Law on Brain Death. J Med Philos, 2016. 41(3): p. 237-56.

16. Liu CW, Yeo C, Lu Zhao B, et al., Brain Death in Asia: Do Public Views Still Influence Organ Donation in the 21st Century? Transplantation, 2019. 103(4): p. 755-763.

17. Jones AH, Dizon ZB, October TW, Investigation of Public Perception of Brain Death Using the Internet. Chest, 2018. 154(2): p. 286-292.

 

 

Figure 1: Graphical representation of respondent distribution by type of inpatient facility (A), specialty qualification (B), and predominant work duties (C). Panel D additionally shows the distribution of specialist ICUs.

Legend: h.: hospital; AIM: anesthesiology and intensive care medicine; DAICM: dept. of anesthesiology and intensive care medicine; ICU: intensive care unit; MV: mechanical ventilation; NIM: next-step intensive medical care unit.

 

 

 

 

	donor program (n=115)		both reasons (n=65)		withdrawal of futile therapy (n=7)		p
	always	never	always	never	always	never
level of consciousness	114 (99%)	1 (1%)	64 (98%)	0 (0%)	7 (100%)	0 (0%)	0.159
corneal r.	114 (99%)	0 (0%)	63 (97%)	1 (2%)	7 (100%)	0 (0%)	0.044
pupillary light r.	114 (99%)	0 (0%)	65 (100%)	0 (0%)	7 (100%)	0 (0%)	1.000
OCR	96 (83%)	7 (6%)	53 (82%)	5 (8%)	6 (86%)	1 (14%)	0.086
OVR	67 (58%)	14 (12%)	42 (65%)	6 (9%)	2 (29%)	2 (29%)	<0.001
nociceptive response from the face	105 (91%)	2 (3%)	60 (92%)	3 (5%)	6 (86%)	0 (0%)	0.037
nociceptive response from the limbs	66 (57%)	30 (26%)	35 (54%)	10 (15%)	5 (71%)	1 (14%)	0.021
cough and gag r.	112 (97%)	1 (1%)	62 (95%)	2 (3%)	5 (71%)	0 (0%)	0.091
apnea test	91 (79%)	0 (0%)	55 (85%)	1 (2%)	5 (71%)	2 (29%)	<0.001

Table 1: Frequency distribution of individual modalities of the clinical examination for determination of brain death –⁠ comparison of physician groups according to the reason for performing the brain‑death examination. Categories: Always (100% of cases), Mostly (>75% of cases), Occasionally (25–75% of cases), Rarely (<25% of cases) and Never (0% of cases). "p" is the chi‑square test result; significance level 0.01.

Legend: r.: reflex; OCR: oculocephalic reflex; OVR: oculovestibular (thermic) reflex.

 

	elimination half‑life (h)	5x elimination half‑life	responses
fentanyl	8	40	24 (12-28)
sufentanil	4	20	16 (12-24)
propofol	1	5	12 (4-24)
midazolam	2,5	12,5	14 (8-24)
dexmedetomidin	2,5	12,5	12 (8-24)

Table 2: Time interval from cessation of sedation to clinical examination for determination of brain death. Results are presented as medians and interquartile ranges.

 

	always	mostly	occasionally	rarely	never
level of consciousness	185 (99; [0,96, 1,00])	1	0	0	1 (1; [0,00, 0,03])
corneal r.	184 (98; [0,95, 1,00])	2	0	0	1 (1; [0,00, 0,03])
pupillary light r.	186 (99; [0,97, 1,00])	1	0	0	0 (0; [0,00, 0,00])
OCR	155 (83; [0,77, 0,88])	10	5	4	13 (7; [0,04, 0,12])
OVR	111 (59; [0,52, 0,66])	22	14	18	22 (12; [0,08, 0,17])
nociceptive response from the face	171 (91; [0,86, 0,95])	6	2	3	5 (3; [0,01, 0,06])
nociceptive response from the limbs	106 (57; [0,50, 0,64])	19	13	8	41 (22; [0,17, 0,28])
cough and gag r.	179 (96; [0,92, 0,98])	1	3	1	3 (2; [0,00, 0,05])
apnea test	151 (81; [0,74, 0,86])	27	4	2	3 (2; [0,00, 0,05])

Table 3: Frequency distribution of individual modalities of the clinical examination for determination of brain death. Categories: always (100% of cases), mostly (>75% of cases), occasionally (25–75% of cases), rarely (<25% of cases) and never (0% of cases). Percentages are shown in parentheses; 95% confidence intervals.

 

Legend: r.: reflex; OCR: oculocephalic reflex; OVR: oculovestibular (thermic) reflex.

 

	always	mostly	occasionally	rarely	never
DSA	14 (8; [0,04, 0,12])	36	24	39	74 (40; [0,33, 0,47])
CTA	48 (26; [0,20, 0,32])	53	21	39	26 (14; [0,10, 0,20])
TCCS	11 (6; [0,03, 0,10])	11	28	49	88 (47; [0,40, 0,54])
BAEP	2 (1; [0,00, 0,04])	7	21	41	116 (62; [0,55, 0,65])
scintigraphy	1 (1; [0,00, 0,03])	18	6	34	128 (68; [0,61, 0,75])

Table 4: Frequency distribution of individual modalities of confirmatory testing for determination of brain death. Categories: always (100% of cases), mostly (>75% of cases), occasionally (25–75% of cases), rarely (<25% of cases) and never (0% of cases). Percentages are shown in parentheses; 95% confidence intervals.

Legend: DSA: digital subtraction angiography; CTA: computed tomography angiography; TCCS: transcranial color‑coded duplex sonography; BAEP: brainstem auditory evoked potentials.