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Optimization of conditions for apnea testing in a hypoxemic brain dead patient

Optimization of conditions for apnea testing in a hypoxemic brain dead patient CASE REPORT Bárbara Vieira Carneiro , Guilherme Henrique Optimization of conditions for apnea testing in a 1 2 Garcia , Larissa Padrão Isensee , Bruno Adler Maccagnan Pinheiro Besen hypoxemic brain dead patient Otimização de condições para teste de apneia em paciente hipoxêmico com morte encefálica 1. Medical Intensive Care Unit, Discipline of ABSTRACT performed with the patient in a prone Medical Emergencies, Department of Internal position, with continuous positive Medicine, Hospital das Clínicas, Faculdade de We report the case of a patient in airway pressure coupled with a T-piece. Medicina, Universidade de São Paulo - São Paulo whom brain death was suspected and The delay in diagnosis was 10 hours, (SP), Brazil. associated with atelectasis and moderate 2. Medical Intensive Care Unit, Division of and organ donation was not possible to severe hypoxemia even though the Physiotherapy, Hospital das Clínicas, Faculdade due to circulatory arrest. This report de Medicina, Universidade de São Paulo - São patient was subjected to protective demonstrates the difficulties in obtaining Paulo (SP), Brazil. ventilation, a closed tracheal suction higher levels of the partial pressure of system, positive end-expiratory pressure, oxygen for the apnea test. The delays in and recruitment maneuvers. Faced the diagnosis of brain death and in the with the failure to obtain an adequate organ donation process are discussed, as partial pressure of oxygen for the apnea well as potential strategies to optimize test, we elected to place the patient in the partial pressure of oxygen to perform a prone position, use higher positive the apnea test according to the current end-expiratory pressure, perform a new recommendations. recruitment maneuver, and ventilate Keywords: Brain death; Critical care; with a higher tidal volume (8mL/kg) Hypoxia; Prone position; Respiration, without exceeding the plateau pressure artificial; Tissue donors of 30cmH O. The apnea test was INTRODUCTION “Brain death” is the terminology used to express the condition of irreversible Conflicts of interest: None. coma associated with the absence of body reflexes and the occurrence of (1) Submitted on August 9, 2018 persistent apnea. Diagnosis of brain death and management of the potential Accepted on November 27, 2018 donor are common in intensive care. Establishing a diagnosis of brain death is a complex process and must be performed with precision. It is a condition that Corresponding author: Bárbara Vieira Carneiro is not well understood by relatives and nonspecialists, and it involves medical, Unidade de Terapia Intensiva do Hospital das (2) ethical, and legal precepts. Clínicas Worldwide, the stages that define brain death are not uniform, and cultural Faculdade de Medicina da Universidade de São Paulo and legal differences may even exist within a single country. In Brazil, the Federal Avenida Dr. Enéas de Carvalho Aguiar, 255, 6º Council of Medicine Resolution 2,137/2017 determines the methodology for andar, sala 6.040 (3) the diagnosis of brain death. Zip code: 05403-000 - São Paulo (SP), Brazil E-mail: babivc5@gmail.com This new Brazilian resolution requires that a single apnea test be administered by one of the physicians responsible for the clinical examination. The resolution Responsible editor: Glauco Adrieno Westphal also requires that patients be ventilated with an inspired oxygen fraction (FiO ) DOI: 10.5935/0103-507X.20190015 of 100% for at least 10 minutes and that mechanical ventilation be optimized Rev Bras Ter Intensiva. 2019;31(1):106-110 This is an open access article under the CC BY license https://creativecommons.org/licenses/by/4.0/). Optimization of conditions for apnea testing in a hypoxemic patient with brain death 107 to reach a partial pressure of oxygen (PaO ) ≥ 200mmHg and a partial pressure of carbon dioxide (PaCO ) between (3) 35 and 45mmHg. Here, we report the case of a patient who was suspected to have brain death associated with atelectasis and moderate to severe hypoxemia. The goal of this report is to demonstrate the difficulties in obtaining safe levels of PaO for the apnea test, as well as potential hypoxemia management strategies that can be used to optimize oxygenation in this context. CASE DESCRIPTION A 57-year-old male, who was previously hypertensive and diabetic, was treated with hydrochlorothiazide, enalapril, and metformin as an outpatient and was admitted to the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo with dysarthria, left hemispatial neglect, and complete and proportional left hemiplegia. After formulating the hypothesis of stroke, the stroke protocol was activated. Computed tomography Figure 1 - Head CT scans before and after decompressive craniectomy (sections (CT) of the skull showed no signs of bleeding, and at the level of the septum pellucidum). (A) Computed tomography of the skull computed tomography angiography of the intra and with 18 hours of evolution. (B) Postoperative computed tomography scan (36 extracranial arteries revealed occlusion at the origin of the hours of evolution) revealed good surgical results. (C) Computed tomography of the skull with 60 hours of evolution and a moderate midline deviation. (D) right middle cerebral artery with caudal extension to the Computed tomography of the skull with 96 hours of evolution and a significant ipsilateral internal carotid artery. midline deviation. The patient underwent thrombolysis after 3 hours and 53 minutes. During the observation period in the The problem emergency department, the level of consciousness of the patient decreased, and thus he required endotracheal The patient became hemodynamically unstable during intubation. The control CT scan of the skull showed right the hours following brain death. We performed volume hemispheric edema, which was consistent with malignant expansion and initiated an infusion of noradrenaline and middle cerebral artery infarction (Figure 1). A right vasopressin. The bedside echocardiogram did not show fronto-temporo-parietal decompressive craniectomy with significant changes in left or right ventricular function. classic durotomy was indicated and performed within 24 We decided to start hormonal resuscitation with the hours of the stroke, and the patient was transported to the enteral administration of thyroid hormone (levothyroxine intensive care unit (ICU) after the surgical procedure. 100µg), hydrocortisone (50mg every 6 hours), and Despite the extensive craniectomy, neurological infusion of glucose and insulin (0.5U/kg/hour). The deterioration increased over the next several days. Since the patient achieved hemodynamic stability but with a patient underwent the most effective therapy to control moderate dose of vasopressors. intracranial hypertension without success, we chose not to Despite hemodynamic stabilization, the patient also implement other measures for intracranial hypertension. presented with moderate hypoxemia (PaO /FiO ~ 110), 2 2 On the fourth day of his ICU stay, the patient lost all and thus it was difficult to perform the apnea test. No body reflexes, was hypotensive and was likely brain dead. clinical evidence of respiratory infection was observed. The tomographic series is described in figure 1. Then, at An ultrasound showed pulmonary collapse in both lung approximately 8 o’clock, we initiated life-support measures bases, which was not observed in the chest X-ray obtained and the brain death protocol for this potential donor and the previous day (Figure 2). notified the organ and tissue procurement service of the hospital. Rev Bras Ter Intensiva. 2019;31(1):106-110 108 Carneiro BV, Garcia GH, Isensee LP, Besen BA hemodynamic instability and worsening of oxygenation. At that time, we maintained the final PEEP at 8cmH O. To achieve safer levels of PaO , we placed the patient in a prone position. A PaO /FiO ratio of 171mmHg was 2 2 obtained once the patient was in a prone position along with an RR of 22bpm, a PEEP of 8cmH O, an FiO of 2 2 0.4, and a TV of 370mL. Since we did not reach the values stipulated by the new resolution, while keeping the patient prone, we chose to use a higher FEEP (15cmH O) associated with the recruitment maneuver and increased the FiO to 1, which maintained the RR at 22bpm and the TV at 370mL. This way, we obtained a PaO of 165mmHg. In the last attempt, we chose to increase the TV up to the plateau pressure limit (8mL/kg for maximum plateau of 30cmH O), with TV of 480mL, while not Figure 2 - Anteroposterior chest X-ray obtained while the patient was in bed. modifying the other parameters. These measures resulted in PaO /FiO of 241mmHg and PaCO of 41mmHg, 2 2 2 The solution thus we started the apnea test. Table 1 summarizes the ventilatory parameters and the We maintained the patient in volume-controlled mode gasometric findings in each stage. with a respiratory rate (RR) of 22 bpm (breaths per minute), a positive end-expiratory pressure (PEEP) of 5cmH O, an The apnea test FiO of 1, a tidal volume (TV) of 370mL, and an initial The apnea test is based on the absence of respiratory PaO of 109mmHg. We used a closed suction system and movements after maximal stimulation of the respiratory attempted to perform a recruitment maneuver with PEEP (1) center by hypercapnia (PaCO > 55mmHg). The test elevation up to 20cmH O, which was interrupted due to 2 Table 1 - Blood gas and evolution of respiratory mechanics for initiation of the apnea test Protective MV + Prone Protective MV + Prone + Variable Protective VM Protective MV + Prone Posttest + high PEEP high PEEP + TV 8mL/kg Time 10:38 a.m. 1:59 p.m. 3:24 a.m. 4:21 p.m. 5:39 p.m. Blood gas parameters pH 7.3 7.29 7.24 7.26 6,97 PaO 109 68.4 165 241 243 PaCO 40.7 39.3 42.2 41.3 93.7 Bicarbonate 19.5 18.5 17.8 17.9 20.6 SBE - 6 - 6.8 - 8.4 - 8.2 - 14.2 SatO 97.2 93.9 99.1 85.8 98.5 Ventilatory parameters PEEP 5 8 15 15 10 FiO 1 0.4 1 1 1 PaO /FiO ratio 109 171 165 241 - 2 2 Respiratory rate 22 22 22 22 - TV 370 370 370 480 - Plateau pressure 20 20 25 30 - ΔP 15 12 10 15 - MV - mechanical ventilation; PEEP - positive end-expiratory pressure; TV - tidal volume; PaO - partial pressure of oxygen; PaCO - partial pressure of carbon dioxide; SBE - standard base 2 2 excess; SatO - oxygen saturation; FiO - fraction of inspired oxygen; ΔP - lung-distending pressure. 2 2 Rev Bras Ter Intensiva. 2019;31(1):106-110 Optimization of conditions for apnea testing in a hypoxemic patient with brain death 109 should be stopped whenever the following is observed: instability or hypoxemia, while the test is terminated in (6) (1) respiratory movements (negative apnea test), (2) 3% for the same reasons. (1,3,4) hemodynamic instability, or (3) severe hypoxemia. Some prerequisites have been established by the new Since the patient required several maneuvers to Brazilian guidelines for initiation of the apnea test: body achieve adequate oxygenation before the test, we elected temperature > 35ºC, systolic blood pressure ≥ 100mmHg to perform the test with the patient in a prone position or mean arterial pressure ≥ 65mmHg, PaCO between 35 (3) with a continuous positive airway pressure (CPAP) valve and 45mmHg, and PaO ≥ 200mmHg. However, no placed in the T tube through which oxygen flowed at a consensus has been established on what the required levels (5) rate of 12L/minute, as previously described. From a of PaO should be for performing the apnea test. Wijdicks hemodynamic standpoint, the patient tolerated the test, et al. (2008) did not observe a significant difference as he maintained 100% saturation throughout the test; between the levels of PaO among those who completed (6) moreover, posttest arterial blood gas analysis confirmed or the apnea test and those who did not. From a clinical the validity of the test (Table 1). point of view, although a minimal PaO is useful to avoid hypoxemia during the test, the cutoff value will not always Evolution be reached, and there are other more effective ways to (5) maintain oxygenation such as performing the CPAP test. We completed the apnea test and the first clinical trial Despite this, the current resolution requires that the apnea at 5:30 p.m. on the same day, which resulted in a 10-hour test be preceded by attempts to optimize oxygenation delay in relation to the suspected diagnosis of brain death. to increase the safety of the test. In contrast, in other The second clinical trial was initiated at 7:15 p.m. by countries, a complementary examination is mandatory another specially trained intensivist. Complementary only for patients who do not tolerate the apnea test or examination (transcranial Doppler) showed total cerebral when the results of the neurological exam are questioned. circulatory arrest. The patient’s family members agreed that In Brazil, the complementary exam is mandatory for all the patient could donate his organs, and procurement was cases, and healthcare personnel do not have the option to scheduled for the following morning. However, overnight, not perform the apnea test, which can result in the loss of the patient developed circulatory arrest due to refractory potential donors. shock, and no organ procurement was possible. The respiratory support recommended for a potential DISCUSSION donor involves the following set of actions: (1) a TV of 6 - 8mL/kg of the patient’s predicted weight without This case demonstrates the difficulty imposed by exceeding the plateau pressure of 30cmH O, (2) a PEEP hypoxemia, a common condition in neurocritical patients, in of 8 - 10cmH O, (3) a closed suction system, (4) CPAP the determination of brain death. The need to optimize the apnea test, and (5) recruitment maneuvers in case of PaO before performing the apnea test delayed the diagnosis ventilator disconnection. This set of actions was evaluated by 10 hours and contributed to the loss of potential donated in a randomized clinical trial, which demonstrated an organs due to circulatory arrest. Despite this outcome, we absolute increase of 27% in the number of lungs procured described a set of additional maneuvers to optimize the pretest (7) for transplant and is recommended by the Brazilian PaO to avoid missing the diagnosis of brain death. Finally, (8) guidelines for maintaining potential donors. we described, for the first time, the performance of the apnea This strategy was not sufficient to optimize oxygenation test with the patient in a prone position to maintain adequate to safe levels in the case presented. Thus, we performed other oxygenation during the procedure. measures that can lead to better oxygenation. We started The apnea test is essential in the process of determining (9) with the patient in the prone position. After 7 hours of brain death. However, this test poses a risk to patients mechanical ventilation in the prone position, two alveolar due to the possibility of hypotension, hypoxemia, (10) recruitment maneuvers, maintenance of high PEEP, and arrhythmias, and cardiac arrest. The occurrence of any of an increase in the TV of 8mL/kg, we obtained an increase these conditions can lead to termination of the test and in PaO compatible with the CPAP apnea test, which was delayed diagnosis of brain death. North American data performed with the patient in the prone position. This set show that 7% of patients with suspected brain death are of maneuvers allowed for a safer apnea test with adequate unable to initiate the apnea test due to hemodynamic levels of PaO before and after the test. Rev Bras Ter Intensiva. 2019;31(1):106-110 110 Carneiro BV, Garcia GH, Isensee LP, Besen BA CONCLUSION that can be used so that the apnea test can be performed safely and effectively, which may reduce the incidence of The present report aimed to highlight the problem of missed diagnosis of brain death due to the difficulty in hypoxemia in neurocritical patients with suspected brain performing the test as recommended in the resolution of death and the implications on the performance of the the Brazilian Federal Council of Medicine. apnea test. We demonstrated a variety of bedside strategies RESUMO contínua nas vias aéreas acoplada em tubo T. O atraso no diag- Relatamos o caso de um paciente que evoluiu com suspeita nóstico foi de 10 horas; a doação de órgãos não foi possível de- de morte encefálica associada à atelectasia e à hipoxemia mode- vido à parada circulatória. Este relato demonstra as dificuldades rada a grave, apesar de instituídos ventilação protetora, sistema para obtenção de níveis de pressão parcial de oxigênio mais altos de aspiração traqueal fechado, pressão positiva ao final da ex- para a realização do teste de apneia. Os atrasos que isso pode piração moderada e manobra de recrutamento. Diante da não acarretar ao diagnóstico de morte encefálica e ao processo de obtenção de pressão parcial de oxigênio adequada para o teste de doação de órgãos são discutidos, além de potenciais estratégias apneia, optamos por pronar o paciente, utilizar pressão positiva de otimização da pressão parcial de oxigênio para realização do expiratória final mais elevada, realizar nova manobra de recruta- teste, conforme as recomendações atuais. mento e ventilar com volume corrente mais elevado (8mL/kg), Descritores: Morte encefálica; Cuidados críticos; Hipóxia; sem ultrapassar pressão de platô de 30cmH O. O teste de apneia Decúbito ventral; Respiração artificial; Doadores de tecidos foi realizado em posição prona, com válvula de pressão positiva REFERENCES 1. Wijdicks EF. Determining brain death. Continuum (Minneap Minn). 7. Mascia L, Pasero D, Slutsky AS, Arguis MJ, Berardino M, Grasso S, et 2015;21(5 Neurocritical Care):1411-24. al. Effect of a lung protective strategy for organ donors on eligibility and 2. Burkle CM, Sharp RR, Wijdicks EF. Why brain death is considered death availability of lungs for transplantation: a randomized controlled trial. and why there should be no confusion. Neurology. 2014;83(16):1464-9. JAMA. 2010;304(23):2620-7. 3. Brasil. Conselho Federal de Medicina. Resolução CFM Nº 2.173/2017. Define 8. Westphal GA, Caldeira Filho M, Vieira KD, Zaclikevis VR, Bartz MC, Wanzuita os critérios do diagnóstico de morte encefálica. (Accessed 26/07, 2018, at R, et al. Guidelines for potential multiple organ donors (adult): part II. https://sistemas.cfm.org.br/normas/visualizar/resolucoes/BR/2017/2173.) Mechanical ventilation, endocrine metabolic management, hematological 4. Wijdicks EF. Brain death guidelines explained. Semin Neurol. and infectious aspects. Rev Bras Ter Intensiva. 2011;23(3):269-82. 2015;35(2):105-15. 9. Gattinoni L, Tognoni G, Pesenti A, Taccone P, Mascheroni D, Labarta V, 5. Lévesque S, Lessard MR, Nicole PC, Langevin S, LeBlanc F, Lauzier F, et Malacrida R, Di Giulio P, Fumagalli R, Pelosi P, Brazzi L, Latini R; Prone- al. Efficacy of a T-piece system and a continuous positive airway pressure Supine Study Group. Effect of prone positioning on the survival of patients system for apnea testing in the diagnosis of brain death. Crit Care Med. with acute respiratory failure. N Engl J Med. 2001;345(8):568-73. 2006;34(8):2213-6. 10. Briel M, Meade M, Mercat A, Brower RG, Talmor D, Walter SD, et al. Higher vs lower positive end-expiratory pressure in patients with acute 6. Wijdicks EF, Rabinstein AA, Manno EM, Atkinson JD. Pronouncing brain lung injury and acute respiratory distress syndrome: systematic review death: Contemporary practice and safety of the apnea test. Neurology. and meta-analysis. JAMA. 2010;303(9):865-73. 2008;71(16):1240-4. Rev Bras Ter Intensiva. 2019;31(1):106-110 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Revista Brasileira de Terapia Intensiva Pubmed Central

Optimization of conditions for apnea testing in a hypoxemic brain dead patient

Revista Brasileira de Terapia Intensiva , Volume 31 (1) – Jan 1, 2019

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Pubmed Central
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0103-507X
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1982-4335
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10.5935/0103-507X.20190015
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Abstract

CASE REPORT Bárbara Vieira Carneiro , Guilherme Henrique Optimization of conditions for apnea testing in a 1 2 Garcia , Larissa Padrão Isensee , Bruno Adler Maccagnan Pinheiro Besen hypoxemic brain dead patient Otimização de condições para teste de apneia em paciente hipoxêmico com morte encefálica 1. Medical Intensive Care Unit, Discipline of ABSTRACT performed with the patient in a prone Medical Emergencies, Department of Internal position, with continuous positive Medicine, Hospital das Clínicas, Faculdade de We report the case of a patient in airway pressure coupled with a T-piece. Medicina, Universidade de São Paulo - São Paulo whom brain death was suspected and The delay in diagnosis was 10 hours, (SP), Brazil. associated with atelectasis and moderate 2. Medical Intensive Care Unit, Division of and organ donation was not possible to severe hypoxemia even though the Physiotherapy, Hospital das Clínicas, Faculdade due to circulatory arrest. This report de Medicina, Universidade de São Paulo - São patient was subjected to protective demonstrates the difficulties in obtaining Paulo (SP), Brazil. ventilation, a closed tracheal suction higher levels of the partial pressure of system, positive end-expiratory pressure, oxygen for the apnea test. The delays in and recruitment maneuvers. Faced the diagnosis of brain death and in the with the failure to obtain an adequate organ donation process are discussed, as partial pressure of oxygen for the apnea well as potential strategies to optimize test, we elected to place the patient in the partial pressure of oxygen to perform a prone position, use higher positive the apnea test according to the current end-expiratory pressure, perform a new recommendations. recruitment maneuver, and ventilate Keywords: Brain death; Critical care; with a higher tidal volume (8mL/kg) Hypoxia; Prone position; Respiration, without exceeding the plateau pressure artificial; Tissue donors of 30cmH O. The apnea test was INTRODUCTION “Brain death” is the terminology used to express the condition of irreversible Conflicts of interest: None. coma associated with the absence of body reflexes and the occurrence of (1) Submitted on August 9, 2018 persistent apnea. Diagnosis of brain death and management of the potential Accepted on November 27, 2018 donor are common in intensive care. Establishing a diagnosis of brain death is a complex process and must be performed with precision. It is a condition that Corresponding author: Bárbara Vieira Carneiro is not well understood by relatives and nonspecialists, and it involves medical, Unidade de Terapia Intensiva do Hospital das (2) ethical, and legal precepts. Clínicas Worldwide, the stages that define brain death are not uniform, and cultural Faculdade de Medicina da Universidade de São Paulo and legal differences may even exist within a single country. In Brazil, the Federal Avenida Dr. Enéas de Carvalho Aguiar, 255, 6º Council of Medicine Resolution 2,137/2017 determines the methodology for andar, sala 6.040 (3) the diagnosis of brain death. Zip code: 05403-000 - São Paulo (SP), Brazil E-mail: babivc5@gmail.com This new Brazilian resolution requires that a single apnea test be administered by one of the physicians responsible for the clinical examination. The resolution Responsible editor: Glauco Adrieno Westphal also requires that patients be ventilated with an inspired oxygen fraction (FiO ) DOI: 10.5935/0103-507X.20190015 of 100% for at least 10 minutes and that mechanical ventilation be optimized Rev Bras Ter Intensiva. 2019;31(1):106-110 This is an open access article under the CC BY license https://creativecommons.org/licenses/by/4.0/). Optimization of conditions for apnea testing in a hypoxemic patient with brain death 107 to reach a partial pressure of oxygen (PaO ) ≥ 200mmHg and a partial pressure of carbon dioxide (PaCO ) between (3) 35 and 45mmHg. Here, we report the case of a patient who was suspected to have brain death associated with atelectasis and moderate to severe hypoxemia. The goal of this report is to demonstrate the difficulties in obtaining safe levels of PaO for the apnea test, as well as potential hypoxemia management strategies that can be used to optimize oxygenation in this context. CASE DESCRIPTION A 57-year-old male, who was previously hypertensive and diabetic, was treated with hydrochlorothiazide, enalapril, and metformin as an outpatient and was admitted to the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo with dysarthria, left hemispatial neglect, and complete and proportional left hemiplegia. After formulating the hypothesis of stroke, the stroke protocol was activated. Computed tomography Figure 1 - Head CT scans before and after decompressive craniectomy (sections (CT) of the skull showed no signs of bleeding, and at the level of the septum pellucidum). (A) Computed tomography of the skull computed tomography angiography of the intra and with 18 hours of evolution. (B) Postoperative computed tomography scan (36 extracranial arteries revealed occlusion at the origin of the hours of evolution) revealed good surgical results. (C) Computed tomography of the skull with 60 hours of evolution and a moderate midline deviation. (D) right middle cerebral artery with caudal extension to the Computed tomography of the skull with 96 hours of evolution and a significant ipsilateral internal carotid artery. midline deviation. The patient underwent thrombolysis after 3 hours and 53 minutes. During the observation period in the The problem emergency department, the level of consciousness of the patient decreased, and thus he required endotracheal The patient became hemodynamically unstable during intubation. The control CT scan of the skull showed right the hours following brain death. We performed volume hemispheric edema, which was consistent with malignant expansion and initiated an infusion of noradrenaline and middle cerebral artery infarction (Figure 1). A right vasopressin. The bedside echocardiogram did not show fronto-temporo-parietal decompressive craniectomy with significant changes in left or right ventricular function. classic durotomy was indicated and performed within 24 We decided to start hormonal resuscitation with the hours of the stroke, and the patient was transported to the enteral administration of thyroid hormone (levothyroxine intensive care unit (ICU) after the surgical procedure. 100µg), hydrocortisone (50mg every 6 hours), and Despite the extensive craniectomy, neurological infusion of glucose and insulin (0.5U/kg/hour). The deterioration increased over the next several days. Since the patient achieved hemodynamic stability but with a patient underwent the most effective therapy to control moderate dose of vasopressors. intracranial hypertension without success, we chose not to Despite hemodynamic stabilization, the patient also implement other measures for intracranial hypertension. presented with moderate hypoxemia (PaO /FiO ~ 110), 2 2 On the fourth day of his ICU stay, the patient lost all and thus it was difficult to perform the apnea test. No body reflexes, was hypotensive and was likely brain dead. clinical evidence of respiratory infection was observed. The tomographic series is described in figure 1. Then, at An ultrasound showed pulmonary collapse in both lung approximately 8 o’clock, we initiated life-support measures bases, which was not observed in the chest X-ray obtained and the brain death protocol for this potential donor and the previous day (Figure 2). notified the organ and tissue procurement service of the hospital. Rev Bras Ter Intensiva. 2019;31(1):106-110 108 Carneiro BV, Garcia GH, Isensee LP, Besen BA hemodynamic instability and worsening of oxygenation. At that time, we maintained the final PEEP at 8cmH O. To achieve safer levels of PaO , we placed the patient in a prone position. A PaO /FiO ratio of 171mmHg was 2 2 obtained once the patient was in a prone position along with an RR of 22bpm, a PEEP of 8cmH O, an FiO of 2 2 0.4, and a TV of 370mL. Since we did not reach the values stipulated by the new resolution, while keeping the patient prone, we chose to use a higher FEEP (15cmH O) associated with the recruitment maneuver and increased the FiO to 1, which maintained the RR at 22bpm and the TV at 370mL. This way, we obtained a PaO of 165mmHg. In the last attempt, we chose to increase the TV up to the plateau pressure limit (8mL/kg for maximum plateau of 30cmH O), with TV of 480mL, while not Figure 2 - Anteroposterior chest X-ray obtained while the patient was in bed. modifying the other parameters. These measures resulted in PaO /FiO of 241mmHg and PaCO of 41mmHg, 2 2 2 The solution thus we started the apnea test. Table 1 summarizes the ventilatory parameters and the We maintained the patient in volume-controlled mode gasometric findings in each stage. with a respiratory rate (RR) of 22 bpm (breaths per minute), a positive end-expiratory pressure (PEEP) of 5cmH O, an The apnea test FiO of 1, a tidal volume (TV) of 370mL, and an initial The apnea test is based on the absence of respiratory PaO of 109mmHg. We used a closed suction system and movements after maximal stimulation of the respiratory attempted to perform a recruitment maneuver with PEEP (1) center by hypercapnia (PaCO > 55mmHg). The test elevation up to 20cmH O, which was interrupted due to 2 Table 1 - Blood gas and evolution of respiratory mechanics for initiation of the apnea test Protective MV + Prone Protective MV + Prone + Variable Protective VM Protective MV + Prone Posttest + high PEEP high PEEP + TV 8mL/kg Time 10:38 a.m. 1:59 p.m. 3:24 a.m. 4:21 p.m. 5:39 p.m. Blood gas parameters pH 7.3 7.29 7.24 7.26 6,97 PaO 109 68.4 165 241 243 PaCO 40.7 39.3 42.2 41.3 93.7 Bicarbonate 19.5 18.5 17.8 17.9 20.6 SBE - 6 - 6.8 - 8.4 - 8.2 - 14.2 SatO 97.2 93.9 99.1 85.8 98.5 Ventilatory parameters PEEP 5 8 15 15 10 FiO 1 0.4 1 1 1 PaO /FiO ratio 109 171 165 241 - 2 2 Respiratory rate 22 22 22 22 - TV 370 370 370 480 - Plateau pressure 20 20 25 30 - ΔP 15 12 10 15 - MV - mechanical ventilation; PEEP - positive end-expiratory pressure; TV - tidal volume; PaO - partial pressure of oxygen; PaCO - partial pressure of carbon dioxide; SBE - standard base 2 2 excess; SatO - oxygen saturation; FiO - fraction of inspired oxygen; ΔP - lung-distending pressure. 2 2 Rev Bras Ter Intensiva. 2019;31(1):106-110 Optimization of conditions for apnea testing in a hypoxemic patient with brain death 109 should be stopped whenever the following is observed: instability or hypoxemia, while the test is terminated in (6) (1) respiratory movements (negative apnea test), (2) 3% for the same reasons. (1,3,4) hemodynamic instability, or (3) severe hypoxemia. Some prerequisites have been established by the new Since the patient required several maneuvers to Brazilian guidelines for initiation of the apnea test: body achieve adequate oxygenation before the test, we elected temperature > 35ºC, systolic blood pressure ≥ 100mmHg to perform the test with the patient in a prone position or mean arterial pressure ≥ 65mmHg, PaCO between 35 (3) with a continuous positive airway pressure (CPAP) valve and 45mmHg, and PaO ≥ 200mmHg. However, no placed in the T tube through which oxygen flowed at a consensus has been established on what the required levels (5) rate of 12L/minute, as previously described. From a of PaO should be for performing the apnea test. Wijdicks hemodynamic standpoint, the patient tolerated the test, et al. (2008) did not observe a significant difference as he maintained 100% saturation throughout the test; between the levels of PaO among those who completed (6) moreover, posttest arterial blood gas analysis confirmed or the apnea test and those who did not. From a clinical the validity of the test (Table 1). point of view, although a minimal PaO is useful to avoid hypoxemia during the test, the cutoff value will not always Evolution be reached, and there are other more effective ways to (5) maintain oxygenation such as performing the CPAP test. We completed the apnea test and the first clinical trial Despite this, the current resolution requires that the apnea at 5:30 p.m. on the same day, which resulted in a 10-hour test be preceded by attempts to optimize oxygenation delay in relation to the suspected diagnosis of brain death. to increase the safety of the test. In contrast, in other The second clinical trial was initiated at 7:15 p.m. by countries, a complementary examination is mandatory another specially trained intensivist. Complementary only for patients who do not tolerate the apnea test or examination (transcranial Doppler) showed total cerebral when the results of the neurological exam are questioned. circulatory arrest. The patient’s family members agreed that In Brazil, the complementary exam is mandatory for all the patient could donate his organs, and procurement was cases, and healthcare personnel do not have the option to scheduled for the following morning. However, overnight, not perform the apnea test, which can result in the loss of the patient developed circulatory arrest due to refractory potential donors. shock, and no organ procurement was possible. The respiratory support recommended for a potential DISCUSSION donor involves the following set of actions: (1) a TV of 6 - 8mL/kg of the patient’s predicted weight without This case demonstrates the difficulty imposed by exceeding the plateau pressure of 30cmH O, (2) a PEEP hypoxemia, a common condition in neurocritical patients, in of 8 - 10cmH O, (3) a closed suction system, (4) CPAP the determination of brain death. The need to optimize the apnea test, and (5) recruitment maneuvers in case of PaO before performing the apnea test delayed the diagnosis ventilator disconnection. This set of actions was evaluated by 10 hours and contributed to the loss of potential donated in a randomized clinical trial, which demonstrated an organs due to circulatory arrest. Despite this outcome, we absolute increase of 27% in the number of lungs procured described a set of additional maneuvers to optimize the pretest (7) for transplant and is recommended by the Brazilian PaO to avoid missing the diagnosis of brain death. Finally, (8) guidelines for maintaining potential donors. we described, for the first time, the performance of the apnea This strategy was not sufficient to optimize oxygenation test with the patient in a prone position to maintain adequate to safe levels in the case presented. Thus, we performed other oxygenation during the procedure. measures that can lead to better oxygenation. We started The apnea test is essential in the process of determining (9) with the patient in the prone position. After 7 hours of brain death. However, this test poses a risk to patients mechanical ventilation in the prone position, two alveolar due to the possibility of hypotension, hypoxemia, (10) recruitment maneuvers, maintenance of high PEEP, and arrhythmias, and cardiac arrest. The occurrence of any of an increase in the TV of 8mL/kg, we obtained an increase these conditions can lead to termination of the test and in PaO compatible with the CPAP apnea test, which was delayed diagnosis of brain death. North American data performed with the patient in the prone position. This set show that 7% of patients with suspected brain death are of maneuvers allowed for a safer apnea test with adequate unable to initiate the apnea test due to hemodynamic levels of PaO before and after the test. Rev Bras Ter Intensiva. 2019;31(1):106-110 110 Carneiro BV, Garcia GH, Isensee LP, Besen BA CONCLUSION that can be used so that the apnea test can be performed safely and effectively, which may reduce the incidence of The present report aimed to highlight the problem of missed diagnosis of brain death due to the difficulty in hypoxemia in neurocritical patients with suspected brain performing the test as recommended in the resolution of death and the implications on the performance of the the Brazilian Federal Council of Medicine. apnea test. We demonstrated a variety of bedside strategies RESUMO contínua nas vias aéreas acoplada em tubo T. O atraso no diag- Relatamos o caso de um paciente que evoluiu com suspeita nóstico foi de 10 horas; a doação de órgãos não foi possível de- de morte encefálica associada à atelectasia e à hipoxemia mode- vido à parada circulatória. Este relato demonstra as dificuldades rada a grave, apesar de instituídos ventilação protetora, sistema para obtenção de níveis de pressão parcial de oxigênio mais altos de aspiração traqueal fechado, pressão positiva ao final da ex- para a realização do teste de apneia. Os atrasos que isso pode piração moderada e manobra de recrutamento. Diante da não acarretar ao diagnóstico de morte encefálica e ao processo de obtenção de pressão parcial de oxigênio adequada para o teste de doação de órgãos são discutidos, além de potenciais estratégias apneia, optamos por pronar o paciente, utilizar pressão positiva de otimização da pressão parcial de oxigênio para realização do expiratória final mais elevada, realizar nova manobra de recruta- teste, conforme as recomendações atuais. mento e ventilar com volume corrente mais elevado (8mL/kg), Descritores: Morte encefálica; Cuidados críticos; Hipóxia; sem ultrapassar pressão de platô de 30cmH O. O teste de apneia Decúbito ventral; Respiração artificial; Doadores de tecidos foi realizado em posição prona, com válvula de pressão positiva REFERENCES 1. Wijdicks EF. Determining brain death. Continuum (Minneap Minn). 7. Mascia L, Pasero D, Slutsky AS, Arguis MJ, Berardino M, Grasso S, et 2015;21(5 Neurocritical Care):1411-24. al. Effect of a lung protective strategy for organ donors on eligibility and 2. Burkle CM, Sharp RR, Wijdicks EF. Why brain death is considered death availability of lungs for transplantation: a randomized controlled trial. and why there should be no confusion. Neurology. 2014;83(16):1464-9. JAMA. 2010;304(23):2620-7. 3. Brasil. Conselho Federal de Medicina. Resolução CFM Nº 2.173/2017. Define 8. Westphal GA, Caldeira Filho M, Vieira KD, Zaclikevis VR, Bartz MC, Wanzuita os critérios do diagnóstico de morte encefálica. (Accessed 26/07, 2018, at R, et al. Guidelines for potential multiple organ donors (adult): part II. https://sistemas.cfm.org.br/normas/visualizar/resolucoes/BR/2017/2173.) Mechanical ventilation, endocrine metabolic management, hematological 4. Wijdicks EF. Brain death guidelines explained. Semin Neurol. and infectious aspects. Rev Bras Ter Intensiva. 2011;23(3):269-82. 2015;35(2):105-15. 9. Gattinoni L, Tognoni G, Pesenti A, Taccone P, Mascheroni D, Labarta V, 5. Lévesque S, Lessard MR, Nicole PC, Langevin S, LeBlanc F, Lauzier F, et Malacrida R, Di Giulio P, Fumagalli R, Pelosi P, Brazzi L, Latini R; Prone- al. Efficacy of a T-piece system and a continuous positive airway pressure Supine Study Group. Effect of prone positioning on the survival of patients system for apnea testing in the diagnosis of brain death. Crit Care Med. with acute respiratory failure. N Engl J Med. 2001;345(8):568-73. 2006;34(8):2213-6. 10. Briel M, Meade M, Mercat A, Brower RG, Talmor D, Walter SD, et al. Higher vs lower positive end-expiratory pressure in patients with acute 6. Wijdicks EF, Rabinstein AA, Manno EM, Atkinson JD. Pronouncing brain lung injury and acute respiratory distress syndrome: systematic review death: Contemporary practice and safety of the apnea test. Neurology. and meta-analysis. JAMA. 2010;303(9):865-73. 2008;71(16):1240-4. Rev Bras Ter Intensiva. 2019;31(1):106-110

Journal

Revista Brasileira de Terapia IntensivaPubmed Central

Published: Jan 1, 2019

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