Comparison of Two Apnea Test Methods, Oxygen Insufflation and Continuous Positive Airway Pressure During Diagnosis of Brain Death: Final Report

Joanna Solek-Pastuszka; Jowita Biernawska; Waldemar Iwańczuk; Klaudyna Kojder; Kornel Chelstowski; Romuald Bohatyrewicz; Marcin Sawicki

doi:10.1007/s12028-018-0608-7

Comparison of Two Apnea Test Methods, Oxygen Insufflation and Continuous Positive Airway Pressure During Diagnosis of Brain Death: Final Report

Neurocrit Care. 2019 Apr;30(2):348-354. doi: 10.1007/s12028-018-0608-7.

Authors

Joanna Solek-Pastuszka¹, Jowita Biernawska², Waldemar Iwańczuk³, Klaudyna Kojder¹, Kornel Chelstowski⁴, Romuald Bohatyrewicz¹, Marcin Sawicki⁵

Affiliations

¹ Department of Anaesthesiology and Intensive Care, Pomeranian Medical University in Szczecin, Unii Lubelskiej 1, 71-252, Szczecin, Poland.
² Department of Anaesthesiology and Intensive Care, Pomeranian Medical University in Szczecin, Unii Lubelskiej 1, 71-252, Szczecin, Poland. lisienko@wp.pl.
³ Department of Anaesthesiology and Intensive Therapy, Regional Hospital in Kalisz, 62-800, Kalisz, Poland.
⁴ Department of Laboratory Diagnostics, Pomeranian Medical University in Szczecin, Al. Powstańców Wlkp. 72j, 70-111, Szczecin, Poland.
⁵ Department of Diagnostic Imaging and Interventional Radiology, Pomeranian Medical University in Szczecin, Unii Lubelskiej 1, 71-252, Szczecin, Poland.

Abstract

Introduction: Deterioration of the pulmonary function after the apnea test (AT) conducted with the classic oxygen insufflation AT (I-AT) is often observed during the brain death (BD) diagnosis procedure. In the present study, two AT methods were compared before a method is recommended for the currently revised Polish BD criteria.

Methods: Classic I-AT and continuous positive airway pressure AT (CPAP-AT) were performed in 60 intensive care unit patients. I-AT was performed at the end of two series of clinical tests, and approximately 1-1.5 h later, after BD was confirmed, a different method, CPAP-AT with 100% FiO₂ and CPAP value of 10 cm H₂O provided by a ventilator in CPAP mode was performed. The patients in I-AT and CPAP-AT groups were further divided into two subgroups: non-hypoxemic (NH) with good lung function before AT (PaO₂/FiO₂ index ≥ 200 mmHg) and hypoxemic (H) with poor lung function (PaO₂/FiO₂ index < 200 mmHg). PaO₂ and PaCO₂ were recorded prior to I-AT and CPAP-AT at time-point one (T1), 5 min after each test at time-point two (T2), and after 10 min prior to the end of tests at time-point three (T3). The I-AT NH subgroup consisted of 50 patients, and CPAP-AT NH subgroup 43 patients. The I-AT H subgroup consisted of 10 patients, and the CPAP-AT H subgroup 17 patients.

Results: In the I-AT NH subgroup, a gradual decrease in PaO₂/FiO₂ was observed throughout the AT but not in the CPAP-AT NH subgroup. The PaO₂/FiO₂ ratio during the AT in the CPAP-AT H group was stable with a slight tendency to increase but not in the I-AT H group. During the first 5 min of the AT, the mean increase in CO₂ was approximately 5 mmHg/min. Most patients in all groups met the AT criteria after 5 min of the test.

Conclusions: The results from the study show that I-AT may compromise pulmonary function in some cases and is one of the reasons for the recommendation of a safer option, CPAP-AT, in the currently revised Polish BD criteria. During AT, the mean CO₂ increase rate was 5 mmHg/min, which, in most patients, would allow the test to be completed after just 5 min.

Keywords: Apnea test; Brain death; Brain death diagnosis; Continuous positive airway pressure.

Publication types

Comparative Study

MeSH terms

Adult
Aged
Apnea / diagnosis*
Brain Death / diagnosis*
Brain Diseases*
Continuous Positive Airway Pressure* / adverse effects
Continuous Positive Airway Pressure* / standards
Critical Care* / standards
Female
Humans
Insufflation* / standards
Male
Middle Aged
Oxygen*
Poland
Practice Guidelines as Topic* / standards

Substances

Oxygen