Positive end-expiratory pressure can increase brain tissue oxygen pressure in hypoxemic severe traumatic brain injury patients

Abstract

Introduction Noninvasive ventilation is a safe and eff ective method to treat acute respiratory failure, minimizing the respiratory workload and oxygenation. Few studies compare the effi cacy of diff erent types of noninvasive ventilation interfaces and their adaptation. Objective To identify the most frequently noninvasive ventilation interfaces used and eventual problems related to their adaptation in critically ill patients. Methods We conducted an observational study, with patients older than 18 years old admitted to the intensive care and step-down units of the Albert Einstein Jewish Hospital that used noninvasive ventilation. We collected data such as reason to use noninvasive ventilation, interface used, scheme of noninvasive ventilation used (continuously, periods or nocturnal use), adaptation, and reasons for nonadaptation. Results We evaluated 245 patients with a median age of 82 years (range of 20 to 107 years). Acute respiratory failure was the most frequent cause of noninvasive ventilation used (71.3%), followed by pulmonary expansion (10.24%), after mechanical ventilation weaning (6.14%) and sleep obstructive apnea (8.6%). The most frequently used interface was total face masks (74.7%), followed by facial masks in 24.5% of the patients, and 0.8% used performax masks. The use of noninvasive ventilation for periods (82.4%) was the most common scheme of use, with 10.6% using it continuously and 6.9% during the nocturnal period only. Interface adaptation occurred in 76% of the patients; the 24% that did not adapt had their interface changed to improve adaptation afterwards. The total face mask had 75.5% of interface adaptation, the facial mask had 80% and no adaptation occurred in patients that used the performax mask. The face format was the most frequent cause of nonadaptation in 30.5% of the patients, followed by patient's related discomfort (28.8%), air leaking (27.7%), claustrophobia (18.6%), noncollaborative patient (10.1%), patient agitation (6.7%), facial trauma or lesion (1.7%), type of mask fi xation (1.7%), and 1.7% patients with other causes. Conclusion Acute respiratory failure was the most frequent reason for noninvasive ventilation use, with the total face mask being the most frequent interface used. The most common causes of interface nonadaptation were face format, patient-related discomfort and air leaking, showing improvement of adaptation after changing the interface used. P2 Exercise training reduces oxidative damage in skeletal muscle of septic rats

Effects of Positive End-Expiratory Pressure on Lung Recruitment, Respiratory Mechanics, and Intracranial Pressure in Mechanically Ventilated Brain-Injured Patients

“…There are several limitations in our study that deserve to be mentioned. First, the sample size is small, despite similar to previous physiological studies exploring the effect of PEEP on lung recruitment (Mascia et al, 2005;Nemer et al, 2011;Mauri et al, 2016Mauri et al, , 2020.…”

“…An a priori sample size calculation was not feasible due to the lack of data on quantitative CT analysis in brain-injured patients, but our sample size was similar to previous physiologic studies regarding PEEP augmentation in ARDS or brain-injured patients (Mascia et al, 2005;Nemer et al, 2011;Mauri et al, 2016Mauri et al, , 2020. Data are reported as median (interquartile range, IQR), if not otherwise specified.…”

“…Therefore, in our institution, a PEEP test is performed to increasing PEEP from 5 to 15 cmH 2 O, assessing both respiratory mechanics and cerebral hemodynamics. These values have previously been demonstrated to be safe and can lead to increased brain oxygenation, without the increase in ICP (Nemer et al, 2011). However, as greater PEEP levels may result in worsening of the respiratory mechanics with eventually increased alveolar hyperdistention (Mascia et al, 2005), two-PEEP CT, when possible, has become part of our routine clinical evaluation and has been performed in our institution in other groups of patients (Ball et al, 2021).…”

“…The use of lung-protective ventilation strategies has been shown to reduce morbidity and mortality in acute respiratory distress syndrome (ARDS) and non-ARDS critically ill patients (Sutherasan et al, 2014;Serpa Neto et al, 2015;Simonis et al, 2018). However, strategies comprising the use of high positive end-expiratory pressure (PEEP) have been challenged in braininjured patients because of concerns regarding their effects on cerebral hemodynamics (Nemer et al, 2011;Borsellino et al, 2016;Robba et al, 2020), in particular intracranial pressure (ICP). Possible mechanisms responsible for ICP augmentation after PEEP application include alveolar overdistension with the increase of arterial partial pressure of carbon dioxide (PaCO 2 ) levels, and hemodynamic instability (Caricato et al, 2005;Mascia et al, 2005;Nemer et al, 2011).…”

Complex Care

“…In ARDS, the alveoli collapse and become fluid filled. Furthermore, researchers have found that PEEP can positively influence the brain tissue oxygen pressure in patients with brain injury and ALI (Nemer et al, 2011). However, PEEP also increases intrathoracic pressure with the potential to increase resistance to passive cerebral venous blood flow and cerebral spinal fluid outflow.…”