NIV Reduces CBF in COPD Patients Without Cognitive Function
Condition: COPD; Non-invasive Ventilation; Cognitive Impairment; Cerebral Blood Flow
MeSH terms: Cognitive Dysfunction
Study type: Interventional

Summary: 
      Objectives: Investigate the acute NIV effects on CBF and cognitive functions in COPD
      patients. Methods: Nine non-hypercapnic stable COPD subjects (FEV1/FVC < lower limit of
      normal) and twelve healthy controls were enrolled. CBF (transcranial Doppler), cognitive
      functions, respiratory and cardiovascular response were tested at baseline, during and after
      non-invasive ventilation.
    

Detailed description: 
      Nine COPD patients were screened from the Respiration Laboratory (RespLab) of Federal
      University of Ceará, and twelve sedentary controls from the general population were also
      assessed. All patients were under stable medical treatment at least two months, and COPD
      diagnosis was made according to GOLD guidelines. Patients were excluded if they had heart
      disease, arterial hypertension, other debilitating pulmonary or non-pulmonary diseases,
      depression, preexisting psychiatric or neurologic disorders, stroke, motor impairment, visual
      or hearing disabilities, mini-mental scale examination score below 20 points, and any disease
      that could influence the effectiveness of NIV application or the performance of cognitive
      tests. The control group consisted of healthy and nonsmoking volunteers.

      After study enrollment, 15 days before the performance of the experimental protocol, patients
      performed neurocognitive tests (Digit Span Test, Digit Symbol-Coding, Corsi Block-tapping,
      Trail Making Test A and B and Stroop Test) and NIV adaptation. Pulmonary function
      (spirometry) was measured in all subjects after a thorough medical history and physical
      examination. Before initiating the protocol, patients were asked about discomfort related to
      NIV or any aspect of the experiment. CBF, capnometry, arterial blood gases (ABG) and
      neurocognitive tests were performed before, during and after NIV.

      CBF was measured by transcranial Doppler by mean of LMCAFV immediately before NIV, during NIV
      at 5, 30 and 60 minutes and after NIV removal at 5 and 30 minutes. ABG were collected
      immediately before the experiment, after one hour of NIV breathing and 30 minutes after NIV
      discontinuation. Respiratory rate (RR), tidal volume (VT), oxygen saturation by pulse
      oximetry (SpO2), heart rate (HR), minute ventilation (VE) and mean systemic arterial blood
      pressure (MAP) were continuously measured by a multiparameter monitor (Dixtal DX-2010™,
      Dixtal, Manaus, Brazil) both on spontaneous respiration and NIV.

      Subjects were tested in the morning and investigated while awake and at the supine position,
      throughout the experiment.
    

Intervention name(s): Non-invasive ventilation
Intervention type(s): Other
Intervention description(s): NIV was provided by BiPAP-Vision™ ventilator (Philips Respironics Inc, Murrysville, PA, USA) set at the BIPAP mode and applied by a nasal mask, with room air, for 60 minutes. Volunteers were studied during the application of NIV (inspiratory pressure of 14cmH2O and expiratory pressure of 4cmH2O), with a pressure support of 10cmH2O and without oxygen support (FIO2 0.21). These pressure levels were chosen based on the current practice of NIV in the intensive care setting.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science