title: Timing of noninvasive ventilation failure: causes, risk factors, and potential remedies.
abstract: BACKGROUND
  Identifying the predictors of noninvasive ventilation (NIV) failure has attracted significant interest because of the strong link between failure and poor outcomes. However, very little attention has been paid to the timing of the failure. This narrative review focuses on the causes of NIV failure and risk factors and potential remedies for NIV failure, based on the timing factor.
  
  
  RESULTS
  The possible causes of immediate failure (within minutes to <1 h) are a weak cough reflex, excessive secretions, hypercapnic encephalopathy, intolerance, agitation, and patient-ventilator asynchrony. The major potential interventions include chest physiotherapeutic techniques, early fiberoptic bronchoscopy, changing ventilator settings, and judicious sedation. The risk factors for early failure (within 1 to 48 h) may differ for hypercapnic and hypoxemic respiratory failure. However, most cases of early failure are due to poor arterial blood gas (ABGs) and an inability to promptly correct them, increased severity of illness, and the persistence of a high respiratory rate. Despite a satisfactory initial response, late failure (48 h after NIV) can occur and may be related to sleep disturbance.
  
  
  CONCLUSIONS
  Every clinician dealing with NIV should be aware of these risk factors and the predicted parameters of NIV failure that may change during the application of NIV. Close monitoring is required to detect early and late signs of deterioration, thereby preventing unavoidable delays in intubation.
authors: Ezgi
authors: E
authors: Ozyilmaz
authors: Aylin Ozsancak
authors: AO
authors: Ugurlu
authors: Department of Specialistic, Diagnostic and Experimental Medicine (DIMES), Respiratory and Critical Care, University of Bologna, Sant'Orsola Malpighi Hospital building #15, Alma Mater Studiorum, via Massarenti n,15, Bologna 40185, Italy. stefanava@gmail.com.
authors: Stefano
authors: S
authors: Nava
mesh_terms: D006801:Humans; D063087:Noninvasive Ventilation; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D012307:Risk Factors; D013997:Time Factors; D017211:Treatment Failure