Timing of Noninvasive Ventilation Failure

Causes, Risk Factors, and Potential Remedies

Ezgi Ozyilmaz; Aylin Ozsancak Ugurlu; Stefano Nava


BMC Pulm Med. 2014;14(19) 

In This Article

Non-patient Related Risk Factors

The timing of the application of NIV is a critical factor. A longer delay between admission and NIV use was shown to be an independent risk factor for NIV failure in patients with hematological malignancy and hypoxemic ARF, probably due to the progression of the underlying disease.[53] Therefore, early use of NIV is recommended. It is also critical not to unduly delay the decision to intubate a patient with failed NIV, because the risk of unanticipated respiratory or cardiac arrest could lead to increased morbidity and mortality.

The location of the NIV therapy is another important determinant in the success of NIV. There are advantages and disadvantages of different locations (including ICUs, step-down units, wards, and emergency care) for NIV application, and these have been discussed in detail elsewhere.[71] The decision about where to perform NIV should be based on matching the capabilities of the units and teams with the patient's clinical severity and the need for monitoring.

The experience and the skills of the staff are other key components of NIV success. One study suggested that training in NIV implementation is an important factor in reducing nasocomial infections and improving survival in critically ill patients with COPD and ACPE.[72] Another found that improvements in skill with time may explain the decreased time spent by nurses at the bedside of patients today compared to data reported 20 years ago.[73]

The choice of ventilator is crucial in NIV success in the acute setting, with inadequate equipment leading to poor tolerance and excessive air leaks being documented as a barrier to NIV use.[74] On average, dedicated NIV platforms perform better than ICU ventilators using the NIV algorithm.[75] In particular, the synchrony between the machine and the patient is better with dedicated NIV platforms.[75]

Although much attention has been paid to the development of new interfaces to increase tolerance and patient comfort, mask intolerance remains a major cause of NIV failure.[32] An oronasal mask is generally the most commonly preferred one in ARF, followed by nasal masks, helmets, and mouthpieces. There are various advantages and disadvantages of these interfaces. In the case of poor tolerance, a wise choice may be the application of the so-called "rotating" strategy proposed by Hilbert et al..[76]

Some authors concluded that humidification during NIV for ARF is controversial and that the effect of humidification on the success of NIV is unclear.[77] However, heated humidification is recommended to minimize the work of breathing and to maximize PaCO2 clearance, with less dead space than ventilators with heat and moisture exchangers.