Elsevier

Journal of Critical Care

Volume 30, Issue 6, December 2015, Pages 1390-1394
Journal of Critical Care

Clinical Potpourri
Prone positioning improves oxygenation in spontaneously breathing nonintubated patients with hypoxemic acute respiratory failure: A retrospective study,☆☆,

https://doi.org/10.1016/j.jcrc.2015.07.008Get rights and content

Abstract

Purpose

Prone positioning (PP) improves oxygenation and outcome of patients with acute respiratory distress syndrome undergoing invasive ventilation. We evaluated feasibility and efficacy of PP in awake, non-intubated, spontaneously breathing patients with hypoxemic acute respiratory failure (ARF).

Material and Methods

We retrospectively studied non-intubated subjects with hypoxemic ARF treated with PP from January 2009 to December 2014. Data were extracted from medical records. Arterial blood gas analyses, respiratory rate, and hemodynamics were retrieved 1 to 2 hours before pronation (step PRE), during PP (step PRONE), and 6 to 8 hours after resupination (step POST).

Results

Fifteen non-intubated ARF patients underwent 43 PP procedures. Nine subjects were immunocompromised. Twelve subjects were discharged from hospital, while 3 died. Only 2 maneuvers were interrupted, owing to patient intolerance. No complications were documented. PP did not alter respiratory rate or hemodynamics. In the subset of procedures during which the same positive end expiratory pressure and Fio2 were utilized throughout the pronation cycle (n = 18), PP improved oxygenation (Pao2/Fio2 124 ± 50 mmHg, 187 ± 72 mmHg, and 140 ± 61 mmHg, during PRE, PRONE, and POST steps, respectively, P < .001), while pH and Paco2 were unchanged.

Conclusions

PP was feasible and improved oxygenation in non-intubated, spontaneously breathing patients with ARF.

Introduction

Acute respiratory failure (ARF) is a common cause of intensive care unit (ICU) admission [1]. Patients with severe ARF are usually managed with intubation and invasive mechanical ventilation (MV), but their clinical course is frequently complicated by ventilator associated pneumonia (VAP) [2]. The risk of VAP is particularly high in patients with malignancies, immunocompromise, and chronic obstructive pulmonary disease (COPD) [3], [4], [5], [6]. Especially in these patient groups, VAP may adversely affect the clinical outcome [7], [8]: thus, it is commonly suggested to avoid intubation and, whenever possible, to employ non-invasive ventilation (NIV) [9], [10].

Prone positioning (PP) during invasive MV has been demonstrated to improve oxygenation and reduce mortality of the most severe acute respiratory distress syndrome (ARDS) patients [11], [12], [13]. In theory, these benefits should apply also to non-intubated patients, in whom PP may improve oxygenation while delaying or even avoiding the need for intubation. This may be particularly useful in patients at high risk of VAP [14].

Reports of the application of PP in spontaneously breathing, non-intubated adult patients are limited to few case reports [15], [16], [17].

In this retrospective observational study, we reviewed the 5-year experience of our ICU in the application of PP in awake, non-intubated, spontaneously breathing patients with hypoxemic ARF, describing the effect of PP on oxygenation, breathing patterns, and hemodynamics.

Section snippets

Material and methods

The study protocol was approved by the local Ethics Committee. Written informed consent was not deemed necessary due to the retrospective design of the study. The medical records of patients admitted to the general ICU of San Gerardo Hospital (Monza, Italy) from January 2009 to December 2014 were retrospectively screened for the following inclusion criteria: (1) arterial partial pressure of oxygen to inspired fraction of oxygen ratio (Pao2/Fio2) lower than 300 mm Hg; (2) at least one

Results

From January 2009 to December 2014, 15 non-intubated patients (5 females and 10 males) with Pao2/Fio2 less than 300 mmHg were treated with PP. Patients’ characteristics are summarized in Table 1. Fourteen patients were adults (median age was 66 [52.5-78.5] years old) while one patient was 16 years old. Nine patients were immunocompromised. Five had previous COPD diagnosis and 4 suffered from malignancies. The median value of SAPS II and APACHE II score were 42 (30.25-49) and 17.5 (15-21.25),

Discussion

The application of PP in patients with ARF has been associated to many benefits: it improves oxygenation by reducing lung ventilation/perfusion mismatch [21] and promoting recruitment of non-aerated dorsal lung regions of the lung [22], [23]. Moreover, it has been hypothesized that PP may help to prevent ventilator-induced lung injury [24]. Recently, a randomized, controlled trial [13] and 2 meta-analyses [11], [12] demonstrated that PP significantly improves survival of the most severe ARDS

Conclusions

We have demonstrated that pronation of awake, spontaneously breathing, non-intubated patients with hypoxemic ARF is feasible, safe, and associated with a significant benefit on oxygenation. Further prospective studies are warranted to confirm our results and to evaluate the effect of PP on other clinically relevant outcomes.

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    Authors contributions: All authors provided substantial contributions to the conception and design, acquisition of data, analysis, and interpretation of findings. Dr Scaravilli and Dr Castagna retrospectively collected and performed analyses of data. Dr Scaravilli, Dr Grasselli, Dr Castagna, Dr Bellani, and Dr Zanella drafted the manuscript and all authors contributed substantially to revisions. All authors gave approval for the final version submitted for publication.

    ☆☆

    Financial Support: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

    Disclosures and Conflict of interest: The authors report no conflict of interest.

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