Ventilatory Parameters in Acute Neurological Injury

The goal of this observational study is to test the association between baseline ventilatory parameters (in particular mechanical power (MP), mechanical power normalized to predicted body weight (MP/PBW) and driving pressure (DP) with the baseline neurological status (assessed through the Glasgow coma score) in adults patients under mechanical ventilation with acute neurological injury secondary to stroke, brain trauma or subarachnoid hemorrhage.

The main question\[s\]it aims to answer are:

1. In patients with acute neurological injury under mechanical ventilation, is there a correlation between the acute neurological injury, assessed using the Glasgow scale on admission, and baseline ventilatory parameters?
2. In patients with acute neurological injury under mechanical ventilation, are the baseline ventilatory parameters altered at baseline?

Adults patients with acute neurological injury (ANI) secondary to stroke, brain trauma or subarachnoid hemorrhage may present extraneurological complications. They occur as a consequence of the release of inflammatory mediators in an altered blood-brain barrier, which reach the circulation and thus alter the functionality of other organs. Of the affected organs, the lung is the most frequently compromised, leading to increased morbidity, mortality, and worse neurological outcomes. It should be noted that a large proportion of patients with ANI require mechanical ventilation (MV), which also through the production of inflammatory mediators, can lead to the development of ventilator-induced lung injury (VILI) and alteration of other organs.

From the above, it can be thought that in patients with ANI, the basal respiratory parameters could be altered and this is important, given that in this group of patients, the ventilatory parameters could generate changes at the brain level, particularly an increase in intracranial pressure (ICP) and variation in PaCO2 that would produce changes in the vasculature and concomitantly in cerebral blood flow. In turn, the use of protective ventilation, recommended in other pathologies such as acute respiratory distress syndrome (ARDS), is not clearly defined for this group of patients. For this reason, the objective of this study is the assessment of baseline ventilatory parameters in patients with ANI, in particular mechanical power (MP), mechanical power normalized to predicted body weight (MP/PBW) and driving pressure (DP) and to determine their association with the baseline neurological status (assessed through the Glasgow coma score). The hypothesis of the study, assuming that the greater the initial neurological damage, the greater the ventilatory alterations, is that MP correlates with the degree of neurological injury. The second hypothesis is that ventilatory variables, particularly MP, are altered at baseline in patients with LNA.

Eligibility Criteria:
Inclusion Criteria:

Acute neurological injury in patients ≥ 16 years of age with requiring mechanical ventilation for neurological causes and without baseline lung injury, defined as: normal chest x-ray and adequate oxygenation; PaO2/FiO2 ≥ 300.Neumovent TS and Neumovent Advance respirators will be used.

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Exclusion Criteria:

Pneumothorax, or a pleural drainage tube. Hemodynamic instability (mean blood pressure ≤ 65 mmHg) or high doses of inotropes (Norepinephrine \> 0.5 gammas/kilo/minute or equivalent).

PaO2/FiO2 \< 80 mmHg. Chronic obstructive pulmonary disease (COPD). Pregnant