Prehospital continuous positive airway pressure (CPAP) for acute respiratory distress: a randomised controlled trial

Public involvement in Australian clinical trials: A systematic review

BACKGROUND

Public involvement enhances the relevance, quality, and impact of research. There is some evidence that public involvement in Australian research lags other countries, such as the United Kingdom. The purpose of the systematic review was to establish the rates and describe the characteristics of public involvement in Australian clinical trials.

METHODS

We reviewed evidence of public involvement in all Australian randomised controlled trials published in the first 6 months of 2021. To determine the quality of public involvement, we used the five-item short-form version of the Guidance of Reporting Involvement Patients and the Public, version 2.

RESULTS

In total, 325 randomised controlled trials were included, of which 17 (5%) reported any public involvement. Six trials reported public involvement in setting the research aim and seven in developing study methods. The authors of one study reflected on the overall role and influence of public involvement in the research.

CONCLUSION

Rate of public involvement in Australian clinical trials is seemingly substantially lower than those reported in countries with similar advanced public health care systems, notably the United Kingdom. Our observations may be explained by a lack of researcher skills in how to involve the public and the failure by major funding agencies in Australia to mandate public involvement when deciding on how to award grant funding.

[Non-invasive Mechanical Ventilation in Acute Respiratory Failure. Clinical Practice Guidelines - on behalf of the German Society of Pneumology and Ventilatory Medicine]

The guideline update outlines the advantages as well as the limitations of NIV in the treatment of acute respiratory failure in daily clinical practice and in different indications.Non-invasive ventilation (NIV) has a high value in therapy of hypercapnic acute respiratory failure, as it significantly reduces the length of ICU stay and hospitalization as well as mortality.Patients with cardiopulmonary edema and acute respiratory failure should be treated with continuous positive airway pressure (CPAP) and oxygen in addition to necessary cardiological interventions. This should be done already prehospital and in the emergency department.In case of other forms of acute hypoxaemic respiratory failure with only mild or moderately disturbed gas exchange (PaO2/FiO2 > 150 mmHg) there is no significant advantage or disadvantage compared to high flow nasal oxygen (HFNO). In severe forms of ARDS NIV is associated with high rates of treatment failure and mortality, especially in cases with NIV-failure and delayed intubation.NIV should be used for preoxygenation before intubation. In patients at risk, NIV is recommended to reduce extubation failure. In the weaning process from invasive ventilation NIV essentially reduces the risk of reintubation in hypercapnic patients. NIV is regarded useful within palliative care for reduction of dyspnea and improving quality of life, but here in concurrence to HFNO, which is regarded as more comfortable. Meanwhile NIV is also recommended in prehospital setting, especially in hypercapnic respiratory failure and pulmonary edema.With appropriate monitoring in an intensive care unit NIV can also be successfully applied in pediatric patients with acute respiratory insufficiency.

Impact of delayed mobile medical team dispatch for respiratory distress calls: a propensity score matched study from a French emergency communication center

BACKGROUND

Shortness of breath is a common complaint among individuals contacting emergency communication center (EMCCs). In some prehospital system, emergency medical services include an advanced life support (ALS)-capable team. Whether such team should be dispatched during the phone call or delayed until the BLS-capable paramedic team reports from the scene is unclear. We aimed to evaluate the impact of delayed MMT dispatch until receiving the paramedic review compared to immediate dispatch at the time of the call on patient outcomes.

METHODS

A cross-sectional study conducted in Lyon, France, using data obtained from the departmental EMCC during the period from January to December 2019. We included consecutive calls related to adult patients experiencing acute respiratory distress. Patients from the two groups (immediate mobile medical team (MMT) dispatch or delayed MMT dispatch) were matched on a propensity score, and a conditional weighted logistic regression assessed the adjusted odds ratios (ORs) for each outcome (mortality on days 0, 7 and 30).

RESULTS

A total of 870 calls (median age 72 [57-84], male 466 53.6%) were sought for analysis [614 (70.6%) "immediate MMT dispatch" and 256 (29.4%) "delayed MMT" groups]. The median time before MMT dispatch was 25.1 min longer in the delayed MMT group (30.7 [26.4-36.1] vs. 5.6 [3.9-8.8] min, p < 0.001). Patients subjected to a delayed MMT intervention were older (median age 78 [66-87] vs. 69 [53-83], p < 0.001) and more frequently highly dependent (16.3% vs. 8.6%, p < 0.001). A higher proportion of patients in the delayed MMT group required bag valve mask ventilation (47.3% vs. 39.1%, p = 0.03), noninvasive ventilation (24.6% vs. 20.0%, p = 0.13), endotracheal intubation (7.0% vs. 4.1%, p = 0.07) and catecholamine infusion (3.9% vs. 1.3%, p = 0.01). After propensity score matching, mortality at day 0 was higher in the delayed MMT group (9.8% vs. 4.2%, p = 0.002). Immediate MMT dispatch at the call was associated with a lower risk of mortality on day 0 (0.60 [0.38;0.82], p < 0.001) day 7 (0.50 [0.27;0.72], p < 0.001) and day 30 (0.56 [0.35;0.78], p < 0.001) CONCLUSIONS: This study suggests that the deployment of an MMT at call in patients in acute respiratory distress may result in decreased short to medium-term mortality compared to a delayed MMT following initial first aid assessment.

EvidenceMap: a three-level knowledge representation for medical evidence computation and comprehension

OBJECTIVE

To develop a computable representation for medical evidence and to contribute a gold standard dataset of annotated randomized controlled trial (RCT) abstracts, along with a natural language processing (NLP) pipeline for transforming free-text RCT evidence in PubMed into the structured representation.

MATERIALS AND METHODS

Our representation, EvidenceMap, consists of 3 levels of abstraction: Medical Evidence Entity, Proposition and Map, to represent the hierarchical structure of medical evidence composition. Randomly selected RCT abstracts were annotated following EvidenceMap based on the consensus of 2 independent annotators to train an NLP pipeline. Via a user study, we measured how the EvidenceMap improved evidence comprehension and analyzed its representative capacity by comparing the evidence annotation with EvidenceMap representation and without following any specific guidelines.

RESULTS

Two corpora including 229 disease-agnostic and 80 COVID-19 RCT abstracts were annotated, yielding 12 725 entities and 1602 propositions. EvidenceMap saves users 51.9% of the time compared to reading raw-text abstracts. Most evidence elements identified during the freeform annotation were successfully represented by EvidenceMap, and users gave the enrollment, study design, and study Results sections mean 5-scale Likert ratings of 4.85, 4.70, and 4.20, respectively. The end-to-end evaluations of the pipeline show that the evidence proposition formulation achieves F1 scores of 0.84 and 0.86 in the adjusted random index score.

CONCLUSIONS

EvidenceMap extends the participant, intervention, comparator, and outcome framework into 3 levels of abstraction for transforming free-text evidence from the clinical literature into a computable structure. It can be used as an interoperable format for better evidence retrieval and synthesis and an interpretable representation to efficiently comprehend RCT findings.

Lived experiences of being cared for by ambulance clinicians when experiencing breathlessness-A phenomenological study

BACKGROUND

Breathlessness is a serious and distressing symptom and a common reason why patients require prehospital care by ambulance clinicians. However, little is known about how patients experience this care when they are in a state of breathlessness.

AIM

The aim of this study is to describe the lived experiences of being cared for by ambulance clinicians when experiencing breathlessness.

METHODS

Fourteen lifeworld interviews were conducted with patients who experienced breathlessness and were cared for by ambulance clinicians. The interviews were analysed using a qualitative phenomenological approach.

FINDINGS

The essential meaning of being cared for by ambulance clinicians when experiencing breathlessness is described in two ways: existential humanising care, in which the experience is that of being embraced by a genuine presence or existential dehumanising care, in which feeling exposed to an objectifying presence is the main experience. This meaning has four constituents: surrendering to and trusting in the care that will come; being exposed to an objectifying presence is violating; being embraced by a genuine presence is relieving; and knowing is dwelling.

CONCLUSION

The findings reveal that the ability of ambulance clinicians to provide existential humanising and trustful care, which is the foundation of professional judgement, was essential in how patients responded to and handled the overall situation when breathlessness.

Non-Invasive Ventilation in the Prehospital Emergency Setting: A Systematic Review and Meta-Analysis

INTRODUCTION

Noninvasive ventilation is a well-established treatment for acute respiratory failure, being increasingly applied in the prehospital setting. This systematic review and meta-analysis aims to investigate whether early prehospital initiation of noninvasive ventilation reduces mortality compared to standard oxygen therapy.

METHODS

We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from inception to February 7^th, 2022, for studies comparing prehospital noninvasive ventilation performed by emergency medical services versus standard oxygen therapy in patients with acute respiratory failure. The primary outcome was mortality at the longest follow-up available.

RESULTS

We included ten randomized studies and two quasi-randomized studies for a total of 1485 patients. Prehospital treatment with noninvasive ventilation compared with standard oxygen therapy did not significantly reduce mortality at the longest follow-up available (107/810 [13%] vs 114/772 [15%]; RR = 0.89; 95% CI, 0.70-1.13; P = 0.34; I²=24%). The endotracheal intubation rate was reduced when receiving prehospital noninvasive ventilation (38/776 [4.9%] vs 81/743 [11%]; RR = 0.44; 95% CI, 0.31-0.63; P < 0.001; I²=0%; number needed to treat 17). The intensive care admission rate (114/532 [21%] vs 129/507 [25%]; RR = 0.85; 95% CI, 0.69-1.04; P = 0.11; I²=0%) and length of hospital stay (mean difference=-1.29 days; 95% CI, -3.35-0.77; P = 0.21; I²=82%) were similar between groups.

CONCLUSIONS

Adults with acute respiratory failure treated in the prehospital setting with noninvasive ventilation had a lower risk of intubation than those managed with standard oxygen therapy, with similar risk of death, intensive care admission, and length of hospital stay.

REVIEW REGISTRATION

PROSPERO CRD42021284947.

Prehospital noninvasive positive pressure ventilation for severe respiratory distress in adult patients: An updated meta-analysis

AIM

To compare the effect of prehospital noninvasive positive pressure ventilation (NIPPV) and standard care for severe respiratory distress.

BACKGROUND

Severe respiratory distress is an important cause of death in adult patients. There is a growing body of research exploring the benefits of nasal intermittent positive pressure ventilation (NIPPV) for patients undergoing severe respiratory distress. However, a systematic review is needed to synthesise and summarise this body of knowledge to identify the effectiveness of NIPPV. This is an update of a meta-analysis first published in 2014.

DESIGN

Meta-analysis based on PRISMA guidelines.

METHODS

Databases including PubMed, Embase, Scopus and the Cochrane Library databases were electronically searched to identify randomised controlled trials (RCTs) that reported NIPPV therapy for adult patients with severe respiratory distress. The retrieval time is limited from inception to August 2021. Two reviewers independently screened literature, extracted data and assessed risk bias of included studies. Meta-analysis was performed by using STATA 11.0 software.

RESULTS

A total of 10 studies involving 1465 patients were included. The meta-analysis results showed that compared with standard care, CPAP therapy decreased intubation rate (RR = 0.43, 95% CI: 0.27-0.67, p < .001, I²  = 0.0%), reduced hospital stay (WMD = -4.19, 95% CI: -5.62, -2.77) and ICU stay (WMD = -0.65, 95% CI: -1.09, -0.20) for patients with severe respiratory distress. However, no significant effects of NIPPV were observed on in-hospital mortality (RR = 0.83, 95% CI: 0.64-1.07) and ICU admission rate (RR = 0.93, 95% CI: 0.73-1.19).

CONCLUSIONS

Adult patients with NIPPV treatment for severe respiratory distress had a significantly lower intubation rate and shorter hospital and ICU stay, compared with those with standard care. However, no effect of NIPPV on in-hospital mortality was observed. Further study is needed by enrolling large-sample original studies.

RELEVANCE TO CLINICAL PRACTICE

Among patients with severe respiratory distress, prehospital NIPPV, compared with standard care, was associated with lower intubation rate and shorter hospital and ICU stay in our study. Although our meta-analysis did not find a relationship between prehospital NIPPV and in-hospital mortality and ICU admission rate, which may be limited by the number of studies included and the small sample size. However, our study still suggested that the use of prehospital NIPPV was beneficial to the condition of patients with severe respiratory distress.

Pre-hospital continuous positive airway pressure after blast lung injury and hypovolaemic shock: a modelling study

BACKGROUND

In non-traumatic respiratory failure, pre-hospital application of CPAP reduces the need for intubation. Primary blast lung injury (PBLI) accompanied by haemorrhagic shock is common after mass casualty incidents. We hypothesised that pre-hospital CPAP is also beneficial after PBLI accompanied by haemorrhagic shock.

METHODS

We performed a computer-based simulation of the cardiopulmonary response to PBLI followed by haemorrhage, calibrated from published controlled porcine experiments exploring blast injury and haemorrhagic shock. The effect of different CPAP levels was simulated in three in silico patients who had sustained mild, moderate, or severe PBLI (10%, 25%, 50% contusion of the total lung) plus haemorrhagic shock. The primary outcome was arterial partial pressure of oxygen (Pao₂) at the end of each simulation.

RESULTS

In mild blast lung injury, 5 cm H₂O ambient-air CPAP increased Pao₂ from 10.6 to 12.6 kPa. Higher CPAP did not further improve Pao₂. In moderate blast lung injury, 10 cm H₂O CPAP produced a larger increase in Pao₂ (from 8.5 to 11.1 kPa), but 15 cm H₂O CPAP produced no further benefit. In severe blast lung injury, 5 cm H₂O CPAP inceased Pao₂ from 4.06 to 8.39 kPa. Further increasing CPAP to 10-15 cm H₂O reduced Pao₂ (7.99 and 7.90 kPa, respectively) as a result of haemodynamic impairment resulting from increased intrathoracic pressures.

CONCLUSIONS

Our modelling study suggests that ambient air 5 cm H₂O CPAP may benefit casualties suffering from blast lung injury, even with severe haemorrhagic shock. However, higher CPAP levels beyond 10 cm H₂O after severe lung injury reduced oxygen delivery as a result of haemodynamic impairment.