-
Critical Care (London, England) Jul 2017The adverse effects of mechanical ventilation in acute respiratory distress syndrome (ARDS) arise from two main causes: unphysiological increases of transpulmonary... (Review)
Review
The adverse effects of mechanical ventilation in acute respiratory distress syndrome (ARDS) arise from two main causes: unphysiological increases of transpulmonary pressure and unphysiological increases/decreases of pleural pressure during positive or negative pressure ventilation. The transpulmonary pressure-related side effects primarily account for ventilator-induced lung injury (VILI) while the pleural pressure-related side effects primarily account for hemodynamic alterations. The changes of transpulmonary pressure and pleural pressure resulting from a given applied driving pressure depend on the relative elastances of the lung and chest wall. The term 'volutrauma' should refer to excessive strain, while 'barotrauma' should refer to excessive stress. Strains exceeding 1.5, corresponding to a stress above ~20 cmHO in humans, are severely damaging in experimental animals. Apart from high tidal volumes and high transpulmonary pressures, the respiratory rate and inspiratory flow may also play roles in the genesis of VILI. We do not know which fraction of mortality is attributable to VILI with ventilation comparable to that reported in recent clinical practice surveys (tidal volume ~7.5 ml/kg, positive end-expiratory pressure (PEEP) ~8 cmHO, rate ~20 bpm, associated mortality ~35%). Therefore, a more complete and individually personalized understanding of ARDS lung mechanics and its interaction with the ventilator is needed to improve future care. Knowledge of functional lung size would allow the quantitative estimation of strain. The determination of lung inhomogeneity/stress raisers would help assess local stresses; the measurement of lung recruitability would guide PEEP selection to optimize lung size and homogeneity. Finding a safety threshold for mechanical power, normalized to functional lung volume and tissue heterogeneity, may help precisely define the safety limits of ventilating the individual in question. When a mechanical ventilation set cannot be found to avoid an excessive risk of VILI, alternative methods (such as the artificial lung) should be considered.
Topics: Barotrauma; Extracorporeal Membrane Oxygenation; Forecasting; Humans; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Mechanics; Tidal Volume; Ventilator-Induced Lung Injury
PubMed: 28701178
DOI: 10.1186/s13054-017-1750-x -
Jornal Brasileiro de Pneumologia :... Jul 2019
Topics: Adult; Barotrauma; Cocaine-Related Disorders; Humans; Male; Mediastinal Emphysema; Radiography, Thoracic; Tomography, X-Ray Computed
PubMed: 31365685
DOI: 10.1590/1806-3713/e20190169 -
Medicina (Kaunas, Lithuania) Jan 2022Dysbarism is a general term which includes the signs and symptoms that can manifest when the body is subject to an increase or a decrease in the atmospheric pressure... (Review)
Review
Dysbarism is a general term which includes the signs and symptoms that can manifest when the body is subject to an increase or a decrease in the atmospheric pressure which occurs either at a rate or duration exceeding the capacity of the body to adapt safely. In the following review, we take dysbarisms into account for our analysis. Starting from the underlying physical laws, we will deal with the pathologies that can develop in the most frequently affected areas of the body, as the atmospheric pressure varies when acclimatization fails. Manifestations of dysbarism range from itching and minor pain to neurological symptoms, cardiac collapse, and death. Overall, four clinical pictures can occur: decompression illness, barotrauma, inert gas narcosis, and oxygen toxicity. We will then review the clinical manifestations and illustrate some hints of therapy. We will first introduce the two forms of decompression sickness. In the next part, we will review the barotrauma, compression, and decompression. The last three parts will be dedicated to gas embolism, inert gas narcosis, and oxygen toxicity. Such an approach is critical for the effective treatment of patients in a hostile environment, or treatment in the emergency room after exposure to extreme physical or environmental factors.
Topics: Barotrauma; Decompression Sickness; Embolism, Air; Humans; Hyperbaric Oxygenation
PubMed: 35056412
DOI: 10.3390/medicina58010104 -
The Cochrane Database of Systematic... Mar 2021High-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support... (Meta-Analysis)
Meta-Analysis
BACKGROUND
High-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support for adults experiencing acute respiratory failure, or at risk of acute respiratory failure, in the intensive care unit (ICU). This is an update of an earlier version of the review.
OBJECTIVES
To assess the effectiveness of HFNC compared to standard oxygen therapy, or non-invasive ventilation (NIV) or non-invasive positive pressure ventilation (NIPPV), for respiratory support in adults in the ICU.
SEARCH METHODS
We searched CENTRAL, MEDLINE, Embase, CINAHL, Web of Science, and the Cochrane COVID-19 Register (17 April 2020), clinical trial registers (6 April 2020) and conducted forward and backward citation searches.
SELECTION CRITERIA
We included randomized controlled studies (RCTs) with a parallel-group or cross-over design comparing HFNC use versus other types of non-invasive respiratory support (standard oxygen therapy via nasal cannulae or mask; or NIV or NIPPV which included continuous positive airway pressure and bilevel positive airway pressure) in adults admitted to the ICU.
DATA COLLECTION AND ANALYSIS
We used standard methodological procedures as expected by Cochrane.
MAIN RESULTS
We included 31 studies (22 parallel-group and nine cross-over designs) with 5136 participants; this update included 20 new studies. Twenty-one studies compared HFNC with standard oxygen therapy, and 13 compared HFNC with NIV or NIPPV; three studies included both comparisons. We found 51 ongoing studies (estimated 12,807 participants), and 19 studies awaiting classification for which we could not ascertain study eligibility information. In 18 studies, treatment was initiated after extubation. In the remaining studies, participants were not previously mechanically ventilated. HFNC versus standard oxygen therapy HFNC may lead to less treatment failure as indicated by escalation to alternative types of oxygen therapy (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.45 to 0.86; 15 studies, 3044 participants; low-certainty evidence). HFNC probably makes little or no difference in mortality when compared with standard oxygen therapy (RR 0.96, 95% CI 0.82 to 1.11; 11 studies, 2673 participants; moderate-certainty evidence). HFNC probably results in little or no difference to cases of pneumonia (RR 0.72, 95% CI 0.48 to 1.09; 4 studies, 1057 participants; moderate-certainty evidence), and we were uncertain of its effect on nasal mucosa or skin trauma (RR 3.66, 95% CI 0.43 to 31.48; 2 studies, 617 participants; very low-certainty evidence). We found low-certainty evidence that HFNC may make little or no difference to the length of ICU stay according to the type of respiratory support used (MD 0.12 days, 95% CI -0.03 to 0.27; 7 studies, 1014 participants). We are uncertain whether HFNC made any difference to the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO/FiO) within 24 hours of treatment (MD 10.34 mmHg, 95% CI -17.31 to 38; 5 studies, 600 participants; very low-certainty evidence). We are uncertain whether HFNC made any difference to short-term comfort (MD 0.31, 95% CI -0.60 to 1.22; 4 studies, 662 participants, very low-certainty evidence), or to long-term comfort (MD 0.59, 95% CI -2.29 to 3.47; 2 studies, 445 participants, very low-certainty evidence). HFNC versus NIV or NIPPV We found no evidence of a difference between groups in treatment failure when HFNC were used post-extubation or without prior use of mechanical ventilation (RR 0.98, 95% CI 0.78 to 1.22; 5 studies, 1758 participants; low-certainty evidence), or in-hospital mortality (RR 0.92, 95% CI 0.64 to 1.31; 5 studies, 1758 participants; low-certainty evidence). We are very uncertain about the effect of using HFNC on incidence of pneumonia (RR 0.51, 95% CI 0.17 to 1.52; 3 studies, 1750 participants; very low-certainty evidence), and HFNC may result in little or no difference to barotrauma (RR 1.15, 95% CI 0.42 to 3.14; 1 study, 830 participants; low-certainty evidence). HFNC may make little or no difference to the length of ICU stay (MD -0.72 days, 95% CI -2.85 to 1.42; 2 studies, 246 participants; low-certainty evidence). The ratio of PaO/FiO may be lower up to 24 hours with HFNC use (MD -58.10 mmHg, 95% CI -71.68 to -44.51; 3 studies, 1086 participants; low-certainty evidence). We are uncertain whether HFNC improved short-term comfort when measured using comfort scores (MD 1.33, 95% CI 0.74 to 1.92; 2 studies, 258 participants) and responses to questionnaires (RR 1.30, 95% CI 1.10 to 1.53; 1 study, 168 participants); evidence for short-term comfort was very low certainty. No studies reported on nasal mucosa or skin trauma.
AUTHORS' CONCLUSIONS
HFNC may lead to less treatment failure when compared to standard oxygen therapy, but probably makes little or no difference to treatment failure when compared to NIV or NIPPV. For most other review outcomes, we found no evidence of a difference in effect. However, the evidence was often of low or very low certainty. We found a large number of ongoing studies; including these in future updates could increase the certainty or may alter the direction of these effects.
Topics: Acute Disease; Adult; Barotrauma; Bias; Critical Care; Hospital Mortality; Humans; Intubation; Length of Stay; Masks; Nasal Mucosa; Noninvasive Ventilation; Oxygen Inhalation Therapy; Patient Reported Outcome Measures; Pneumonia; Randomized Controlled Trials as Topic; Respiration, Artificial; Respiratory Insufficiency; Treatment Failure
PubMed: 33661521
DOI: 10.1002/14651858.CD010172.pub3 -
Heart (British Cardiac Society) Jun 2022As the popularity of scuba diving increases internationally, physicians interacting with divers in the clinical setting must be familiar with the cardiovascular stresses... (Review)
Review
As the popularity of scuba diving increases internationally, physicians interacting with divers in the clinical setting must be familiar with the cardiovascular stresses and risks inherent to this activity. Scuba presents a formidable cardiovascular challenge by combining unique environmental conditions with the physiologic demands of underwater exercise. Haemodynamic stresses encountered at depth include increased hydrostatic pressure leading to central shifts in plasma volume coupled with cold water stimuli leading to simultaneous parasympathetic and sympathetic autonomic responses. Among older divers and those with underlying cardiovascular risk factors, these physiologic changes increase acute cardiac risks while diving. Additional scuba risks, as a consequence of physical gas laws, include arterial gas emboli and decompression sickness. These pathologies are particularly dangerous with altered sensorium in hostile dive conditions. When present, the appropriate management of patent foramen ovale (PFO) is uncertain, but closure of PFO may reduce the risk of paradoxical gas embolism in divers with a prior history of decompression sickness. Finally, similar to other Masters-level athletes, divers with underlying traditional cardiovascular risk should undergo complete cardiac risk stratification to determine 'fitness-to-dive'. The presence of undertreated coronary artery disease, occult cardiomyopathy, channelopathy and arrhythmias must all be investigated and appropriately treated in order to ensure diver safety. A patient-centred approach facilitating shared decision-making between divers and experienced practitioners should be utilised in the management of prospective scuba divers.
Topics: Decompression Sickness; Diving; Embolism, Paradoxical; Foramen Ovale, Patent; Humans; Prospective Studies
PubMed: 34670825
DOI: 10.1136/heartjnl-2021-319601 -
Pulmonology 2020
Topics: Barotrauma; Cannula; Diving; Humans; Incidence; Male; Mediastinal Emphysema; Mediastinum; Oxygen Inhalation Therapy; Pressure; Radiography, Thoracic; Subcutaneous Emphysema; Treatment Outcome; Young Adult
PubMed: 31735688
DOI: 10.1016/j.pulmoe.2019.09.010 -
Deutsches Arzteblatt International Sep 2015
Topics: Decompression Sickness; Diving; Foramen Ovale, Patent; Humans; Physical Examination
PubMed: 26396052
DOI: 10.3238/arztebl.2015.0614c -
Critical Care (London, England) Oct 2018
Topics: Animals; Barotrauma; Disease Models, Animal; Humans; Pulmonary Atelectasis; Ventilator-Induced Lung Injury
PubMed: 30360756
DOI: 10.1186/s13054-018-2199-2 -
The New England Journal of Medicine Oct 2017
Topics: Adult; Decompression Sickness; Embolism, Air; Humans; Male; Portal Vein; Radiography, Abdominal; Skin; Tomography, X-Ray Computed; Vomiting
PubMed: 29045210
DOI: 10.1056/NEJMicm1615505 -
Pneumologie (Stuttgart, Germany) Sep 2016Decompression injuries occur on account of the special hyperbaric effects during the emerge phase and require superior therapeutic knowledge. Vitally important is... (Review)
Review
Decompression injuries occur on account of the special hyperbaric effects during the emerge phase and require superior therapeutic knowledge. Vitally important is emergency treatment with high concentrated oxygen at an early stage. Sever decompression injuries require oxygenation in a hyperbaric treatment chamber.
Topics: Decompression Sickness; Diving; Emergency Medical Services; Evidence-Based Medicine; Humans; Hyperbaric Oxygenation; Treatment Outcome
PubMed: 27603947
DOI: 10.1055/s-0042-111704