Fig. 62.1
Strategies for using NIV in the post-extubation period (NIV noninvasive ventilation, ARF acute respiratory failure, SBT spontaneous breathing trial, post-extub. post-extubation
62.2 Concerns with Weaning/Extubation from MV
62.2.1 Definitions
Weaning from MV is the entire process that allows passing more or less quickly from MV to spontaneous breathing, or “de-ventilation,” leading to extubation. Weaning failure is classically defined as failure of a spontaneous breathing trial (SBT), whereas extubation failure is defined as the need for early reintubation (48–72 h) after a planned extubation [1, 3]. Nevertheless, the definition of weaning success or failure should also now consider the development of post-extubation NIV, described as “weaning in progress” [1]. In this situation, the time needed to assess weaning/extubation failure should probably be longer, possibly up to 7 days [4].
62.2.2 Epidemiology and Impact of Weaning/Extubation Difficulties
MV can lead to many complications, including prolonged MV due to weaning/extubation difficulties, delaying the extubation time, as well as risk of reintubation and its own complications; all these situations may increase the patient’s morbidity-mortality. Weaning/extubation difficulties may also be related to the underlying disease, and chronic obstructive pulmonary disease (COPD) patients represent one of the main high-risk populations [1, 3]. Hence, the ICU clinician should consider the feasibility and potential issue of the weaning/extubation process as soon as possible, according to the underlying status, to optimize the weaning/extubation conditions, limit the MV duration, and eventually propose alternative techniques to conventional weaning.
62.3 Role of NIV in the Post-extubation Period
62.3.1 Definitions and Objectives
When applying NIV in the post-extubation period, the ICU clinician should consider three different indications according to their respective objectives and reported results in the literature [5] (Fig. 62.1). The objective of NIV used as a weaning/extubation technique (to facilitate early liberation from MV) is to reduce MV duration (intubation) in patients exhibiting weaning difficulties (one or more SBT failures). The objective of NIV used for the management of post-extubation ARF is to avoid reintubation according to two strategies: either to prevent the occurrence of post-extubation ARF in patients at risk of extubation failure (i.e., preventive or prophylactic NIV strategy) (Table 62.1), or to treat the occurrence of post-extubation ARF following an extubation (24–48 h) that most often is scheduled (i.e., curative or rescue strategy).
Age ≥ 65 years |
APACHE II score > 12 (day of extubation) |
Chronic respiratory disease (COPD) |
Heart failure |
More than one comorbidity (other than heart failure) |
More than one consecutive SBT failure |
PaCO2 > 45 mmHg during SBT or following extubation |
Inefficient cough |
Post-extubation stridor |
Morbid obesity (BMI ≥ 35 kg/m2) |
62.3.2 Physiopathological Rationale to Apply NIV in the Post-extubation Period
Despite the absence of endotracheal prosthesis, NIV can meet the physiological objectives of any type of mechanical ventilation (decrease in the work of breathing, improvement in the breathing pattern, gas exchange, and dyspnea) with a good hemodynamic tolerance [2, 6]. Therefore, NIV application in the post-extubation period should consider the following main objectives: to counteract the different physiopathological factors involved in the weaning/extubation failure, to help physicians with difficulties in predicting results of the weaning/extubation process, and, finally, to treat or prevent the occurrence of a post-extubation ARF, sometimes not foreseeable. Finally, it should be kept in mind that NIV is as efficient and beneficial when there is an underlying hypercapnia (PaCO2 > 45 mmHg), a frequent situation in cases of weaning/extubation failure [1, 3].
62.3.3 Clinical Rationale to Apply NIV in the Post-extubation Period
Weaning/extubation from MV should be considered as a true challenge for the ICU clinician. The clinical basis to apply NIV in the post-extubation period is closely related to the epidemiological and physiopathological data involved in weaning/extubation difficulties and failure, as mentioned above. In addition, efficacy and clinical benefit of NIV in morbidity and mortality (avoiding intubation, reducing nosocomial infections, and survival improvement) for the initial management of hypercapnic ARF, leading to routine practice in severe acute exacerbation in COPD patients [7], also represents a strong argument for using NIV in the post-extubation period. In fact, the ICU clinician must find the optimal compromise between the risks of unduly prolonged intubation and those of a too early weaning and extubation process [5]. Therefore, any strategy with the aim of reducing morbidity and mortality of prolonged MV or reintubation appears relevant and should be developed to improve patient prognosis, particularly in those at high risk of weaning/extubation failure [1, 3].
62.3.4 Results of NIV Use in the Post-extubation Period
62.3.4.1 NIV as a Weaning/Extubation Technique from Mechanical Ventilation
Two noncontrolled clinical studies have previously suggested the feasibility of NIV in this indication [8, 9]. Thereafter, six randomized controlled trials (RCTs) that compared weaning with NIV to conventional weaning were conducted [1, 10–14] (Table 62.2). The results were in favor of NIV in five of the studies [4, 10–13] (Table 62.2). These RCTs have also been included in four systematic reviews or meta-analyses [5, 15–17]. The large Cochrane systematic review (994 patients, 16 RCTs including the six previous English RCTs) stratified its results according to the underlying respiratory disease (COPD or mixed chronic respiratory failure (CRF)) [17]. Finally, available data show that NIV used as an early weaning/extubation technique in medical populations, mainly COPD or CRF patients, permits a significant decrease in the following outcome parameters: weaning failure, risk of reintubation, duration of MV not related to weaning, ICU and in-hospital length of stay, MV complications (nosocomial pneumonia, tracheostomy), and mortality. Furthermore, the benefit with regard to survival may be more important, as there is an underlying COPD and hypercapnia (PaCO2 > 45 mmHg) during the SBT. Early extubation relayed with NIV appears, therefore, to be a reliable, safe, and beneficial weaning technique in difficult-to-wean medical patients, mainly those with COPD.
Table 62.2
Characteristics of the main randomized controlled trials applying NIV in the post-extubation period
Indications/studies [ref.] | Study type | Population characteristics | NIV modalities/control group | NIV experience | Main results |
|---|---|---|---|---|---|
Weaning/extubation (control group: invasive conventional weaning or oxygen therapy) | |||||
Nava et al. [10] | Multicentric (3 centers) | Selected CRF, COPD n = 50 | PSV, FM, Cont, ICUv/PSV | ≥5 years | Favor NIV |
Girault et al. [11] | Monocentric | Selected CRF, mixed (COPD = 51 %) n = 33 | PSV or ACV, FM or N, Int. ICUv/PSV | ≥5 years | Favor NIV |
Ferrer et al. [12] | Multicentric (3 centers) | Selected CRF, mixed (COPD = 44 %) n = 43 | BiPAP, FM or N, Cont., SPEv/PSV or ACV | ≥5 years | Favor NIV |
Wang et al. [13] | Multicentric (11 centers) | Selected CRF, COPD n = 90 | BiPAP, FM, Int., SPEv/PSV or IMV | – | Favor NIV |
Prasad et al. [14] | Monocentric | Selected CRF, COPD n = 30 | BiPAP, FM, Cont., SPEv/PSV | – | Similar |
Girault et al. [4] | Multicentric (13 centers) | Selected CRF, mixed (COPD = 69 %) n = 208 | PSV or BiPAP, FM, Cont., ICUv or SPEv/PSV or T tube/O2 #: | ≥10 years | Favor NIV |
Post-extubation ARF prevention (control group: standard oxygen therapy) | |||||
Nava et al. [21] | Multicentric (3 centers) | Heterogenous (CRF/COPD = 33 %) at risk of extubation failure n = 97
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