Introduction: Physiotherapist usually uses a clinical examination, including auscultation, an analysis of blood gasses and chest imaging to determine the indication for chest physiotherapy, to choose the treatment protocol and evaluate the efficacy of the management. Lung ultrasound (LUS) presents greater accuracy than chest X-ray in the diagnosis of lung deficiencies interesting the physiotherapist. So, it could allow the physiotherapist to determine the indication for chest physiotherapy and thus avoid unnecessary or inappropriate treatments. No study has evaluated the impact of LUS on clinical decisions in chest physiotherapy in ICU patients.

Objective: To evaluate the impact of using the results of lung and diaphragm US on clinical decisions in chest physiotherapy in hypoxemic patients hospitalized in ICU.

Method: The physiotherapist carries out a clinical examination and analyses the complementary tests (chest X-ray, chest CT-scan and blood gasses if available). Following the examination, he will put forward one or several hypotheses concerning the respiratory deficiency and will confirm or not the indication for chest physiotherapy. If respiratory physiotherapy is indicated, the physiotherapist will specify the protocol.

A lung and diaphragm US will be done following the evaluation of the clinical physiotherapist, and will make it possible to answer the question: are the results of the lung and diaphragm US compatible with the hypotheses put forward? The LUS report will be given to the clinical physiotherapist. He will specify the respiratory physiotherapy protocol according to the results of the US-scan.

The modification of the clinical decision will be assessed with the Net Reclassification Index (NRI).

Expected results: We expect that decisions for chest physiotherapy will be modified by LUS. The expected benefit for patients is therefore that they will be given a chest physiotherapy protocol that is better suited to the type of respiratory deficiency they are suffering from.

Research hypothesis The lung and diaphragm ultrasound findings provided to the physiotherapist will modify his/her clinical decision-making in regards to chest physiotherapy treatment in the critical care patient.

Objectives Principal objective The principal objective of this study is to evaluate the impact of using the results of lung and diaphragm US on clinical decisions by physiotherapists regarding chest physiotherapy in patients hospitalized in an ICU.

Secondary objectives

1. Determine the accuracy of physiotherapist diagnosis of lung pathology using routine clinical assessment versus LUS findings;
2. Determine the frequency of change in chest physiotherapy treatment with the addition of LUS results to clinical assessment;
3. Determine the frequency of change in medical treatment (determined by intensivist) following the addition of LUS results to clinical assessment findings.
4. Evaluate the diagnostic accuracy of LUS in predicting duration of mechanical ventilation and mortality.

Methodology:

Type of study This is a multi-centre prospective (patients enrolled on admission) interventional study evaluating a routine assessment/treatment. The study intends to assess the impact of lung and diaphragm ultrasound on the usual physiotherapist's clinical decision-making process. Each included patient will be clinically assessed by a clinical physiotherapist, and then will have a lung and diaphragm ultrasound by another physiotherapist/operator blinded to the clinical assessment findings. The lung and diaphragm ultrasound findings will then be presented to both the intensivist and clinical physiotherapist to evaluate the impact on the independent clinical decision-making by both the intensivist and physiotherapist.

Data collections

The following data will be collected:

• Demographic: age, sex, BMI, smoking, alcohol consumption, history of cirrhosis, diabetes or a chronic respiratory disease, heart failure;
• Reason for hospitalization, medical diagnosis if different;
• Treatments: hypnotics, opiates, steroids and anti-hypertensives, oxygen therapy, mechanical ventilation, NIV, tracheotomy;
• Duration of mechanical ventilation
• Duration of ICU stay
• Vital signs: RR, HR, PA, SpO2, RASS, Glasgow;
• Clinical hypotheses of the clinical physiotherapist;
• LUS findings;
• Choice of chest physiotherapy protocol (before and after ultrasonography).

Nature of the routine care to be evaluated Procedure 1: Decision-making process in chest physiotherapy The clinical physiotherapist is the physiotherapist who manages patients in the CCU.

As soon as chest physiotherapy is prescribed, the physiotherapist carries out a clinical examination and analyses the complementary tests (chest X-ray, chest CT-scan and blood gasses if available). He/she also consults the patient's medical record to find out the reason for admission to the CCU and the medical diagnosis if the critical care physician has made one. Following the examination, he/she will put forward one or several hypotheses concerning the respiratory deficiency (and not the disease - medical diagnosis) and will confirm or not the indication for chest physiotherapy. If respiratory physiotherapy is indicated, the physiotherapist will specify the protocol.

A lung and diaphragm US will be done (see below) following the evaluation of the clinical physiotherapist, and will make it possible to answer the question: are the results of the lung and diaphragm US compatible with the hypotheses put forward? The LUS report will be given to the clinical physiotherapist. It will specify the respiratory physiotherapy protocol according to the results of the US-scan.

Procedure 2: lung and diaphragm US The LUS will be performed by the physiotherapist/operator, who will be blinded to the clinical evaluation of the clinical physiotherapist and the patient's status. The operator will not take part in the management of the patients concerned. The semiology of lung and diaphragm US is described. The following syndromes will be searched for: normal profile, alveolar-interstitial syndrome, pulmonary consolidation, pleural effusion, pneumothorax and diaphragm dysfunction. The physiotherapist/operator will write a detailed LUS-scan report, which will be given to the clinical physiotherapist. It will include the LUS diagnosis and describe the signs observed in the different regions of the chest. The clinical physiotherapist is trained to interpret LUS reports.

In case of mechanically ventilated patient at St. Vincent Hospital (Sydney, Australia), LUS scan will be performed immediately following intubation. Additionnal LUS scans will be performed 72h after intubation and Immediately prior to or following extubation.

Number of patients to recruit and duration of participation for each patient Given the high prevalence of hypoxemia in ICUs, the systematic respiratory assessment in these patients by the physiotherapist and our relatively non-restrictive inclusion criteria, we believe we can recruit more than 300 patients per year.

Inclusion criteria

• Hypoxemia(SpO2/FiO2< 315 (15))(indication for chest physiotherapy)(cf. annexe 1);
• Medical prescription for chest physiotherapy;
• First session of chest physiotherapy;
• Chest X-ray<12h available;
• Physiotherapist/operator qualified in LUS available;
• Patient's consent.

Exclusion criteria

• Presence of a contra-indication for chest physiotherapy;
• Absence of hypoxemia;
• Absence of a prescription for chest physiotherapy;
• Absence of a chest X-ray < 12h from the time of physiotherapy assessment;
• Physiotherapist/operator qualified in LUS not available;
• Lung and diaphragm US not possible (surgical emphysema, dressing, scarring, drains etc.);
• Refusal of the patient or a relative to participate in the study;
• Patients to be discharged on the day of the study;
• Patients in palliative care;
• Withdrawal/limitations of medical care with impending death.

The data that support the findings of this study will be openly available in "figshare".

At publication.

The data that support the findings of this study will be openly available