Death by Neurological Criteria: a Review of Diagnostic Practise, Aimed at Proposal of a Standardised Protocol at Knh

Abstract

Introduction: The definition and diagnosis of death has become more complicated because of the advancement in critical care medicine especially advanced respiratory and cardiac support.1 Early on, death was only diagnosed with the cessation of cardiorespiratory activity. It was noted however that some patients who had sustained fatal brain injury would remain in irreversible coma despite respiratory system being supported by MV.1 The Concept of Brain Death thus was born. In developed countries, there has been a concerted effort to more clearly define the concept and develop guidelines on its diagnosis. Advance in transplant medicine and advantages of deceased donors have contributed the need for stronger legislative regulations. This study has reviewed the practice in KNH, identified gaps in practice and recommended a standardized protocol for DNC.2 Study Title: Death by Neurological Criteria: A review of diagnostic practice, aimed at proposal of a standardized protocol at KNH Study Design: Descriptive Cross-Sectional Broad Objective: To review the practice of determining Death by Neurological Criteria at KNH Study Area: Critical Care Units in KNH Study Population: All patients diagnosed with BD in KNH during the study Sample Size: Thirty eight patients Data Collection: Used a Data collection tool developed from AAN/AAP checklist on diagnosing BD Data Analysis: SPSS v29.0 Used. Univariate analysis was done using Measures of central tendency & dispersion. Bivariate analysis using Chi-Square and Fishers Exact Test, ANOVA. Study Results: During the study period (July-December 2022), a 38 patients were recruited into the study. Age range was 9 months to 82 years with a mean and median of 41 years. Adults were 84%. Patients were distributed in 6 CCUs, with Main CCU having 18 (47%). The initial DNC exam was done > 24hours after severe TBI or a CPR event, for all patients and all had acceptable inter-exam interval for age. All patients had a pre-exam GCS of 2T and had a radiologically confirmed cause of irreversible coma. Severe TBI was the commonest cause of Coma (44.7%) Co-morbidities were noted to contribute negatively to the disease process of the patient. Confounders to BD evaluation accounted for included: Temperature, Blood pressure, CNS Depressants and metabolic disorders. All subjects had a core temperature > 350C. About 29% of patients had a pre-exam SBP below 2 SD age in the intial DNC exam. Prior to 1st DNC, 84% of patients were on a CNS depressant. The figure was 52.6% for the 2nd exam. The most common CNS depressant was Phenytoin. Drug levels were not measured prior to BD exam. Severe metabolic disorders were noted prior 1st (39.5%) and 2nd (17%) BD exam. The commonest of these was severe metabolic acidosis. Neurologic examination was the most consistently done aspect of BD exam. All brainstem reflexes were done in most patients. Oculovestibular reflex was not done in patients with otorrhea. Pupillary size varied from 4-8mm. Apnoea test was done only 10 out of 62 exams. No documented reason was given for not doing it. Where it was done, the standard procedure was followed. The test was aborted in 5 examinations due to bradycardia and desaturations. No ancillary test was done for any patient. BD exams were largely done by resident doctors especially in neurosurgery, followed by anesthesia. Post DNC diagnosis, MV settings and medical treatment were de-escalated. Supportive care was generally maintained. CPR was noted to have been done for all patients at asystole, inspite of BD. No deceased organ donation was reported. No formal documentation structure or checklist for BD evaluation was available. Conclusion: The practice of BD evaluation in KNH is not yet standardized. Different examiners may leave out certain sections of the exam. Some confounders were not completely corrected prior to a few of the examinations. Apnoea test, a crucial part of the exam, was not consistently done. Having a standardized protocol and checklist will ensure adherence to the process and improve documentation.