Weaning covers the entire process of liberating the patient from mechanical support and from the endotracheal tube. Many controversial questions remain concerning the best methods for conducting this process. An International Consensus Conference was held in April 2005 to provide recommendations regarding the management of this process. An 11-member international jury answered five pre-defined questions. 1) What is known about the epidemiology of weaning problems? 2) What is the pathophysiology of weaning failure? 3) What is the usual process of initial weaning from the ventilator? 4) Is there a role for different ventilator modes in more difficult weaning? 5) How should patients with prolonged weaning failure be managed? The main recommendations were as follows. 1) Patients should be categorised into three groups based on the difficulty and duration of the weaning process. 2) Weaning should be considered as early as possible. 3) A spontaneous breathing trial is the major diagnostic test to determine whether patients can be successfully extubated. 4) The initial trial should last 30 min and consist of either T-tube breathing or low levels of pressure support. 5) Pressure support or assist-control ventilation modes should be favoured in patients failing an initial trial/trials. 6) Noninvasive ventilation techniques should be considered in selected patients to shorten the duration of intubation but should not be routinely used as a tool for extubation failure.

/pdf/weaning-from-mechanical-ventilation-4yn2mbde5t.pdf

Weaning from mechanical ventilation

Background Avoiding intubation is a major goal in the management of respiratory failure, particularly in immunosuppressed patients. Nevertheless, there are only limited data on the efficacy of noninvasive ventilation in these high-risk patients. Methods We conducted a prospective, randomized trial of intermittent noninvasive ventilation, as compared with standard treatment with supplemental oxygen and no ventilatory support, in 52 immunosuppressed patients with pulmonary infiltrates, fever, and an early stage of hypoxemic acute respiratory failure. Periods of noninvasive ventilation delivered through a face mask were alternated every three hours with periods of spontaneous breathing with supplemental oxygen. The ventilation periods lasted at least 45 minutes. Decisions to intubate were made according to standard, predetermined criteria. Results The base-line characteristics of the two groups were similar; each group of 26 patients included 15 patients with hematologic cancer and neutropenia. Fewer patient...

Noninvasive Ventilation in Immunosuppressed Patients with Pulmonary Infiltrates, Fever, and Acute Respiratory Failure

Noninvasive mechanical ventilation (NIV) is widely used in the acute care setting for acute respiratory failure (ARF) across a variety of aetiologies. This document provides European Respiratory Society/American Thoracic Society recommendations for the clinical application of NIV based on the most current literature. The guideline committee was composed of clinicians, methodologists and experts in the field of NIV. The committee developed recommendations based on the GRADE (Grading, Recommendation, Assessment, Development and Evaluation) methodology for each actionable question. The GRADE Evidence to Decision framework in the guideline development tool was used to generate recommendations. A number of topics were addressed using technical summaries without recommendations and these are discussed in the supplementary material. This guideline committee developed recommendations for 11 actionable questions in a PICO (population–intervention–comparison–outcome) format, all addressing the use of NIV for various aetiologies of ARF. The specific conditions where recommendations were made include exacerbation of chronic obstructive pulmonary disease, cardiogenic pulmonary oedema, de novo hypoxaemic respiratory failure, immunocompromised patients, chest trauma, palliation, post-operative care, weaning and post-extubation. This document summarises the current state of knowledge regarding the role of NIV in ARF. Evidence-based recommendations provide guidance to relevant stakeholders.

https://erj.ersjournals.com/content/erj/50/2/1602426.full.pdf

Official ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure

http://emergpa.net/wp/wp-content/uploads/2011/03/NIV.pdf

Non-invasive ventilation in acute respiratory failure

ContextNoninvasive ventilation (NIV) has been associated with lower rates of
endotracheal intubation in populations of patients with acute respiratory
failure.ObjectiveTo compare NIV with standard treatment using supplemental oxygen administration
to avoid endotracheal intubation in recipients of solid organ transplantation
with acute hypoxemic respiratory failure.Design and SettingProspective randomized study conducted at a 14-bed, general intensive
care unit of a university hospital.PatientsOf 238 patients who underwent solid organ transplantation from December
1995 to October 1997, 51 were treated for acute respiratory failure. Of these,
40 were eligible and 20 were randomized to each group.InterventionNoninvasive ventilation vs standard treatment with supplemental oxygen
administration.Main Outcome MeasuresThe need for endotracheal intubation and mechanical ventilation at any
time during the study, complications not present on admission, duration of
ventilatory assistance, length of hospital stay, and intensive care unit mortality.ResultsThe 2 groups were similar at study entry. Within the first hour of treatment,
14 patients (70%) in the NIV group, and 5 patients (25%) in the standard treatment
group improved their ratio of the PaO2 to the fraction of inspired
oxygen (FIO2). Over time, a sustained improvement in PaO2 to FIO2 was noted in 12 patients (60%) in the NIV group,
and in 5 patients (25%) randomized to standard treatment (P = .03). The use of NIV was associated with a significant reduction
in the rate of endotracheal intubation (20% vs 70%; P
= .002), rate of fatal complications (20% vs 50%; P
= .05), length of stay in the intensive care unit by survivors (mean [SD]
days, 5.5 [3] vs 9 [4]; P = .03), and intensive care
unit mortality (20% vs 50%; P = .05). Hospital mortality
did not differ.ConclusionsThese results indicate that transplantation programs should consider
NIV in the treatment of selected recipients of transplantation with acute
respiratory failure.

https://jamanetwork.com/journals/jama/articlepdf/192270/jce90013.pdf

Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation: a randomized trial.

CONTEXT\nNoninvasive ventilation (NIV) has been associated with lower rates of endotracheal intubation in populations of patients with acute respiratory failure.\n\n\nOBJECTIVE\nTo compare NIV with standard treatment using supplemental oxygen administration to avoid endotracheal intubation in recipients of solid organ transplantation with acute hypoxemic respiratory failure.\n\n\nDESIGN AND SETTING\nProspective randomized study conducted at a 14-bed, general intensive care unit of a university hospital.\n\n\nPATIENTS\nOf 238 patients who underwent solid organ transplantation from December 1995 to October 1997, 51 were treated for acute respiratory failure. Of these, 40 were eligible and 20 were randomized to each group.\n\n\nINTERVENTION\nNoninvasive ventilation vs standard treatment with supplemental oxygen administration.\n\n\nMAIN OUTCOME MEASURES\nThe need for endotracheal intubation and mechanical ventilation at any time during the study, complications not present on admission, duration of ventilatory assistance, length of hospital stay, and intensive care unit mortality.\n\n\nRESULTS\nThe 2 groups were similar at study entry. Within the first hour of treatment, 14 patients (70%) in the NIV group, and 5 patients (25%) in the standard treatment group improved their ratio of the PaO2 to the fraction of inspired oxygen (FIO2). Over time, a sustained improvement in PaO2 to FIO2 was noted in 12 patients (60%) in the NIV group, and in 5 patients (25%) randomized to standard treatment (P = .03). The use of NIV was associated with a significant reduction in the rate of endotracheal intubation (20% vs 70%; P = .002), rate of fatal complications (20% vs 50%; P = .05), length of stay in the intensive care unit by survivors (mean [SD] days, 5.5 [3] vs 9 [4]; P = .03), and intensive care unit mortality (20% vs 50%; P = .05). Hospital mortality did not differ.\n\n\nCONCLUSIONS\nThese results indicate that transplantation programs should consider NIV in the treatment of selected recipients of transplantation with acute respiratory failure.

Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation

Objective: To evaluate treatment with noninvasive ventilation (NIV) by nasal mask as an alternative to endotracheal intubation and conventional mechanical ventilation in patients with hematologic malignancies complicated by acute respiratory failure to decrease the risk of hemorrhagic complications and increase clinical tolerance. Design: Prospective clinical study. Setting: Hematologic and general intensive care unit (ICU), University of Rome “La Sapienza”. Patients: 16 consecutive patients with acute respiratory failure complicating hematologic malignancies. Interventions: NIV was delivered via nasal mask by means of a BiPAP ventilator (Respironics, USA); we evaluated the effects on blood gases, respiratory rate, and hemodynamics along with tolerance, complications, and outcome. Measurements and results: 15 of the 16 patients showed a significant improvement in blood gases and respiratory rate within the first 24 h of treatment. Arterial oxygen tension (PaO2), PaO2/FIO2 (fractional inspired oxygen) ratio, and arterial oxygen saturation significantly improved after 1 h of treatment (43 ± 10 vs 88 ± 37 mmHg; 87 ± 22 vs 175 ± 64; 81 ± 9 vs 95 ± 4 %, respectively) and continued to improve in the following 24 h (p < 0.01). Five patients died in the ICU following complications independent of the respiratory failure, while 11 were discharged from the ICU in stable condition after a mean stay of 4.3 ± 2.4 days and were discharged in good condition from the hospital. Conclusions: NIV by nasal mask proved to be feasible and appropriate for the treatment of respiratory failure in hematologic patients who were at high risk of intubation – related complications.

/pdf/noninvasive-ventilation-for-the-treatment-of-acute-n1ernomhhs.pdf

Noninvasive ventilation for the treatment of acute respiratory failure in patients with hematologic malignancies: a pilot study.

To investigate the role played by the endotracheal tube (ETT) in the correct evaluation of respiratory system mechanics with the end inflation occlusion method during constant flow controlled mechanical ventilation. General ICU, university of Rome “La Sapienza”. 12 consecutive patients undergoing controlled mechanical ventilation. We compared the values of minimal resistance of the respiratory system (i.e. airway resistance) (RRS min) obtained: i) subtracting the theoretical value of ETT resistance from the difference between P max and P1, measured on airway pressure tracings obtained from the distal end of the ETT; ii) directly measuring airway pressure 2 cm below the ETT, thus automatically excluding ETT resistance from the data. The values of RRS min obtained by measuring airway pressure below the ETT were significantly lower than those obtained by measuring airway pressure at the distal end of the ETT and subtracting the theoretical ETT resistance (4.5±2.8 versus 2.5±1.6 cm H2O/l/s,p<0.01). When precise measurements of ohmic resistances are required in mechanically ventilated patients, the measurements must be obtained from airways pressure data obtained at tracheal level. The “in vivo” positioning of ETT significantly increases the airflow resistance of the ETT.

/pdf/evaluation-of-respiratory-system-resistance-in-mechanically-2f5e53y03m.pdf

Evaluation of respiratory system resistance in mechanically ventilated patients: the role of the endotracheal tube.

Objective: To evaluate respiratory mechanics in the early phase of decompensation in a group of seven patients with severe kyphoscoliosis (KS) (Cobb angle > 90 °) requiring mechanical ventilatory support. Design: Prospective clinical study with a control group. Setting: General intensive care unit at University of Rome “La Sapienza”. Patients: Seven consecutive patients affected by severe KS in the early phase of acute decompensation and a control group of six ASA (American Society of Anesthesiology) 1 subjects who were mechanically ventilated during minor surgery. Measurements and results: Respiratory mechanics were evaluated during constant flow-controlled mechanical ventilation at zero end-expiratory pressure with the end-inspiratory and end-expiratory occlusion technique. In five patients who showed increased ohmic resistance (RRSmin), we evaluated the possibility of reversing this increase with a charge dose of 6 mg/kg doxophylline i. v. In four KS patients, in whom a reliable esophageal pressure was confirmed by a positive occlusion test, we separated respiratory system data into lung and chest wall component. All KS patients showed reduced values of respiratory compliance (CRS) and increased respiratory resistance (RRS). The average basal values of CRS were 36 ± 10 vs 58 ± 8.5 cmH2O in control patients; RRSmax was 20 ± 3.1 vs. 4.5 ± 1.2 cmH2O/l per s; RRSmin 6.2 ± 1.2 vs. 2 ± 0.5 cmH2O/l per s: ΔRRS 14 ± 2.6 cmH2O vs 2.4 ± 0.7 cmH2O/l per s. All KS patients showed low values of intrinsic positive end-expiratory pressure (PEEPi) (1.8 ± 1.5 cmH2O). Separation of lung and chest-wall mechanics, performed only in four patients, showed a reduction in both lung (66.7 ± 7.2 ml/cmH2O) and chest wall values (84 ± 8.2 ml/cmH2O), while both RmaxL and RmaxCW were increased (16.6 ± 2 and 2.8 ± 0.4 cmH2O/l per s, respectively). Infusion of doxophylline did not significantly change respiratory mechanics when evaluated 15, 30, and 45 min after the infusion. Conclusions: During acute decompensation, both lung and chest-wall compliance are severely reduced in KS patients: conversely, and, contrary to that in patients with chronic obstructive pulmonary disease, increases in airway resistance and PEEPi seem to play only a secondary role.

/pdf/respiratory-system-mechanics-in-the-early-phase-of-acute-efo1edrcw4.pdf

A. Lappa

Papers

Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation: a randomized trial.

Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation

Noninvasive ventilation for the treatment of acute respiratory failure in patients with hematologic malignancies: a pilot study.

Evaluation of respiratory system resistance in mechanically ventilated patients: the role of the endotracheal tube.

Respiratory system mechanics in the early phase of acute respiratory failure due to severe kyphoscoliosis