Near-Drowning: Clinical Course of Lung Injury in Adults

Microbiological features of drowning-associated pneumonia: a systematic review and meta-analysis

BACKGROUND

Drowning-associated pneumonia (DAP) is frequent in drowned patients, and possibly increases mortality. A better understanding of the microorganisms causing DAP could improve the adequacy of empirical antimicrobial therapy. We aimed to describe the pooled prevalence of DAP, the microorganisms involved, and the impact of DAP on drowned patients.

METHODS

Systematic review and meta-analysis of studies published between 01/2000 and 07/2023 reporting on DAP occurrence and microorganisms involved.

RESULTS

Of 309 unique articles screened, 6 were included, involving 688 patients. All were retrospective cohort studies, with a number of patients ranging from 37 to 270. Studies were conducted in Europe (France N = 3 and Netherland N = 1), United States of America (N = 1) and French West Indies (N = 1). Mortality ranged between 18 to 81%. The pooled prevalence of DAP was 39% (95%CI 29-48), similarly following freshwater (pooled prevalence 44%, 95%CI 36-52) or seawater drowning (pooled prevalence 42%, 95%CI 32-53). DAP did not significantly impact mortality (pooled odds ratio 1.43, 95%CI 0.56-3.67) but this estimation was based on two studies only. Respiratory samplings isolated 171 microorganisms, mostly Gram negative (98/171, 57%) and mainly Aeromonas sp. (20/171, 12%). Gram positive microorganisms represented 38/171 (22%) isolates, mainly Staphylococcus aureus (21/171, 12%). Water salinity levels had a limited impact on the distribution of microorganisms, except for Aeromonas sp. who were exclusively found following freshwater drowning (19/106, 18%) and never following seawater drowning (0%) (p = 0.001). No studies reported multidrug-resistant organisms but nearly 30% of the isolated microorganisms were resistant to amoxicillin-clavulanate, the drug that was the most commonly prescribed empirically for DAP.

CONCLUSIONS

DAP are commonly caused by Gram-negative bacteria, especially Aeromonas sp. which is exclusively isolated following freshwater drowning. Empirical antimicrobial therapy should consider covering them, noting than amoxicillin-clavulanate may be inadequate in about one-third of the cases. The impact of DAP on patients' outcome is still unclear.

Vaporization of perfluorocarbon attenuates sea-water-drowning-induced acute lung injury by deactivating the NLRP3 inflammasomes in canines

Seawater-drowning-induced acute lung injury (SD-ALI) is a life-threatening disorder characterized by increased alveolar-capillary permeability, an excessive inflammatory response, and refractory hypoxemia. Perfluorocarbons (PFCs) are biocompatible compounds that are chemically and biologically inert and lack toxicity as oxygen carriers, which could reduce lung injury in vitro and in vivo. The aim of our study was to explore whether the vaporization of PFCs could reduce the severity of SD-ALI in canines and investigate the underlying mechanisms. Eighteen beagle dogs were randomly divided into three groups: the seawater drowning (SW), perfluorocarbon (PFC), and control groups. The dogs in the SW group were intratracheally administered seawater to establish the animal model. The dogs in the PFC group were treated with vaporized PFCs. Probe-based confocal laser endomicroscopy (pCLE) was performed at 3 h. The blood gas, volume air index (VAI), pathological changes, and wet-to-dry (W/D) lung tissue ratios were assessed. The expression of heme oxygenase-1 (HO-1), nuclear respiratory factor-1 (NRF1), and NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasomes was determined by means of quantitative real-time polymerase chain reaction (qRT-PCR) and immunological histological chemistry. The SW group showed higher lung injury scores and W/D ratios, and lower VAI compared to the control group, and treatment with PFCs could reverse the change of lung injury score, W/D ratio and VAI. PFCs deactivated NLRP3 inflammasomes and reduced the release of caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18) by enhancing the expression of HO-1 and NRF1. Our results suggest that the vaporization of PFCs could attenuate SD-ALI by deactivating NLRP3 inflammasomes via the HO-1/NRF1 pathway.

Does adjunctive hemoadsorption provide benefit in the management of ischemia-reperfusion syndrome following near-drowning? A case report

Drowning remains a significant global health concern, claiming over 300,000 lives annually, with a disproportionate impact on young individuals in low-and middle-income countries. Conventional mechanical ventilation, while common, falls short in addressing the hypoxemia and hypercapnia often observed in severe near-drowning cases. Veno-venous extracorporeal membrane oxygenation (vvECMO) emerges as a critical intervention for cardiopulmonary failure post-drowning. This case report delves into the pivotal role of ischemia-reperfusion injury (IRI) in a near-drowning-related pathology. Following the initial insult, reoxygenation exacerbates the inflammatory cascade, resulting in a surge of pro-inflammatory mediators. In this context, CytoSorb®, a hemoadsorption cartridge, demonstrates promise by effectively removing these mediators from circulation. This report outlines its application in a critically ill adolescent patient who experienced near-drowning, presenting a compelling case for CytoSorb as an adjunctive therapy in managing IRI-induced hyperinflammation.

Wilderness Medical Society Clinical Practice Guidelines for the Treatment and Prevention of Drowning: 2024 Update

The Wilderness Medical Society convened a panel to review available evidence supporting practices for acute management of drowning in out-of-hospital and emergency care settings. Literature about definitions and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded available evidence supporting practices according to the American College of Chest Physicians criteria and then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking. This is the second update to the original practice guidelines published in 2016 and updated in 2019.

Drowning rule-out with novices (DROWN) in ultrasound

Objectives

Non-fatal drownings confer significant morbidity and mortality in the United States. Chest radiograph (CXR) is typically used as a screening modality for interstitial edema but lacks sensitivity early after submersion. No study has evaluated lung ultrasound in assessing for pulmonary edema after submersion events and we hypothesized that lung point-of-care (POC) ultrasound can identify interstitial edema in patients presenting after non-fatal drownings.

Methods

Patients presenting to the emergency department after a submersion event were eligible if a CXR was obtained as part of their care. Emergency medicine residents performed a lung POC ultrasound and provided a "novice" interpretation of "normal" or "abnormal," which was independently reviewed by a blinded expert sonographer. Patients were contacted 2 weeks after presentation to assess for late sequela.

Results

A prospective convenience sample of 59 patients included 21 adults (36%) and 38 children (64%) enrolled over 17 months with a median age of 6. Twenty-four (41%) patients had abnormalities on CXR. Of these, 20 patients had a positive ultrasound per novice interpretation. Compared to CXR, ultrasound had an overall sensitivity of 83% and a specificity of 66% for detecting pulmonary edema in non-fatal drownings. Notably, out of 35 subjects with a negative CXR, there were 12 (34%) cases with a positive lung ultrasound, 10 of which required hospital admission.

Conclusion

Lung POC ultrasound has a moderate sensitivity and specificity when performed by novice sonographers to detect pulmonary edema presenting to an ED setting after a non-fatal drowning event.

Clinical and microbiological features of drowning-associated pneumonia: a retrospective multicentre cohort study

OBJECTIVE

Pneumonia is the most frequent infectious complication in patients who have experienced drowning that requires intensive care unit (ICU) admission. We aimed to describe clinical, microbiological, and therapeutic data as well as predictors and impacts of such pneumonia on patients' outcomes.

METHODS

We conducted a retrospective, multicentre study (2013-2020) of 270 consecutive patients admitted for drowning to 14 ICUs in Western France. Their baseline characteristics and outcomes were compared according to the occurrence of drowning-associated pneumonia (DAP), defined as pneumonia diagnosed within 48 hours of ICU admission. A Cox regression model was used to compare survival on day 28, and logistic regression was used to identify risk factors for DAP. Microbiological characteristics and empirical antibacterial treatment were also analysed.

RESULTS

Among the 270 patients admitted to the ICU for drowning, 101 (37.4%) and 33 (12.2%) experienced pneumonia and microbiologically proven DAP, respectively. The occurrence of pneumonia was associated with higher severity scores at ICU admission (median Simplified Acute Physiology Score II, 34 [interquartile range {IQR}, 25-55] vs. 45 [IQR, 28-67]; p 0.006) and longer ICU length of stay (2 days [IQR, 1-3] vs. 4 days [IQR, 2-7]; p < 0.001). The 28-day mortality rate was higher among these patients (29/101 [28.7%] vs. 26/169 [15.4%]; p 0.013). Microbiologically proven DAP remained associated with higher 28-day mortality after adjustments for cardiac arrest and water salinity (adjusted hazard ratio, 1.86 [95% CI, 1.06-3.28]; p 0.03). A microbiological analysis of respiratory samples showed a high proportion of gram-negative bacilli (23/56; 41.1%), with a high prevalence of amoxicillin-clavulanate resistance (12/33; 36.4%).

CONCLUSIONS

Pneumonia is a common complication in patients admitted in the ICU for drowning and is associated with increased mortality.

Development and Validation of Indicators for Population Injury Surveillance in Hong Kong: Development and Usability Study

BACKGROUND

Injury is an increasingly pressing global health issue. An effective surveillance system is required to monitor the trends and burden of injuries.

OBJECTIVE

This study aimed to identify a set of valid and context-specific injury indicators to facilitate the establishment of an injury surveillance program in Hong Kong.

METHODS

This development of indicators adopted a multiphased modified Delphi research design. A literature search was conducted on academic databases using injury-related search terms in various combinations. A list of potential indicators was sent to a panel of experts from various backgrounds to rate the validity and context-specificity of these indicators. Local hospital data on the selected core indicators were used to examine their applicability in the context of Hong Kong.

RESULTS

We reviewed 142 articles and identified 55 indicators, which were classified into 4 domains. On the basis of the ratings by the expert panel, 13 indicators were selected as core indicators because of their good validity and high relevance to the local context. Among these indicators, 10 were from the construct of health care service use, and 3 were from the construct of postdischarge outcomes. Regression analyses of local hospitalization data showed that the Hong Kong Safe Community certification status had no association with 5 core indicators (admission to intensive care unit, mortality rate, length of intensive care unit stay, need for a rehabilitation facility, and long-term behavioral and emotional outcomes), negative associations with 4 core indicators (operative intervention, infection rate, length of hospitalization, and disability-adjusted life years), and positive associations with the remaining 4 core indicators (attendance to accident and emergency department, discharge rate, suicide rate, and hospitalization rate after attending the accident and emergency department). These results confirmed the validity of the selected core indicators for the quantification of injury burden and evaluation of injury-related services, although some indicators may better measure the consequences of severe injuries.

CONCLUSIONS

This study developed a set of injury outcome indicators that would be useful for monitoring injury trends and burdens in Hong Kong.

The Therapeutic Effect and the Possible Mechanism of C-Phycocyanin in Lipopolysaccharide and Seawater-Induced Acute Lung Injury

Background

Seawater drowning-induced acute lung injury (ALI) is a severe clinical condition characterized by increased alveolar-capillary permeability, excessive inflammatory response, and refractory hypoxemia. C-phycocyanin (C-PC), a biliprotein found in blue-green algae such as spirulina platensis, is widely used in the food and dietary nutritional supplement fields due to its beneficial pharmacological effects. Previous studies have revealed that C-PC has anti-inflammatory, antioxidant, and anti-apoptotic activities.

Purpose

Therefore, this study investigated the protective effect and underlying mechanisms of C-PC on lipopolysaccharide (LPS) and seawater (SW) induced ALI (SW and LPS-induced ALI).

Methods

An SW and LPS mouse model of ALI mice was established through intratracheal administration of 5mg/kg LPS and 25% SW. Different doses of C-PC (100, 200 and 400 mg/kg) were administered by intraperitoneal injection for seven days. In addition, gap junction communication in RAW264.7 and MLE-12 cells was determined following stimulation with 25% SW and 10 μg/ml LPS after treatment with C-PC (120 μg/ml). Moreover, the arterial partial pressure of oxygen, lung wet/dry weight ratios, total protein content and MPO levels in the bronchoalveolar lavage fluid (BALF), and the histopathologic and ultrastructure staining of the lung tissues were determined. The oxidative stress index, levels of the pro-inflammatory mediators, epithelial cell viability and apoptosis, and the regulatory effect of C-PC on the NF-κB/NLRP3 axis were investigated.

Results

The results showed that C-PC significantly alleviated pathological damages, suppressed oxidative stress, inflammation and apoptosis, and enhanced the viability of epithelial cells in the lung tissues. Furthermore, C-PC was shown to inhibit activation of the NF-κB/NLRP3 pathway and the formation of the NLRP3 inflammasome complex.

Conclusions

In conclusion, C-PC shows promising therapeutic value in SW and LPS-induced ALI/ARDS, providing new insight into ALI/ARDS treatment.

Early application of non-invasive ventilation for children with pulmonary edema after drowning

BACKGROUND

The present study aimed to assess the efficacy of non-invasive ventilation (NIV) on the clinical course, oxygenation, need for invasive mechanical ventilation (IMV), and outcomes for children with pulmonary edema after drowning.

METHODS

We conducted a retrospective chart review. Children who were referred to the pediatric emergency department due to drowning-related pulmonary edema and underwent NIV between May 2014 and October 2020 were included. Demographics, vital signs, clinical findings, and results of laboratory and radiologic investigations were recorded. Patients were divided into six groups using the Szpilman classification system. The need for IMV, the need for pediatric intensive care unit admission, and the length of NIV treatment and stay in the pediatric intensive care unit were recorded for each patient.

RESULTS

Twenty-five patients were enrolled. According to the Szpilman classification, 13 (52.0%) patients were evaluated as grade 3 and 12 (48.0%) as grade 4. All patients were treated with bi-level positive airway pressure in the spontaneous / timed mode. A significant increase in oxygen saturation (SpO₂) and SpO₂/fraction of inspired oxygen ratios was observed from the beginning of NIV treatment and this increase was also observed for the second and fourth hours. There was a decrease in respiratory rate at the fourth hour of NIV treatment. No patient subsequently deteriorated to require IMV.

CONCLUSIONS

We have reported a favorable clinical course of drowning patients who underwent early use of NIV in the pediatric emergency department. Management of drowning patients with pulmonary edema by NIV with close follow-up can be successfully applied in selected cases.

2021 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Neonatal Life Support; Education, Implementation, and Teams; First Aid Task Forces; and the COVID-19 Working Group

The International Liaison Committee on Resuscitation initiated a continuous review of new, peer-reviewed published cardiopulmonary resuscitation science. This is the fifth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations; a more comprehensive review was done in 2020. This latest summary addresses the most recently published resuscitation evidence reviewed by International Liaison Committee on Resuscitation task force science experts. Topics covered by systematic reviews in this summary include resuscitation topics of video-based dispatch systems; head-up cardiopulmonary resuscitation; early coronary angiography after return of spontaneous circulation; cardiopulmonary resuscitation in the prone patient; cord management at birth for preterm and term infants; devices for administering positive-pressure ventilation at birth; family presence during neonatal resuscitation; self-directed, digitally based basic life support education and training in adults and children; coronavirus disease 2019 infection risk to rescuers from patients in cardiac arrest; and first aid topics, including cooling with water for thermal burns, oral rehydration for exertional dehydration, pediatric tourniquet use, and methods of tick removal. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, according to the Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations or good practice statements. Insights into the deliberations of the task forces are provided in Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces listed priority knowledge gaps for further research.

2021 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

The International Liaison Committee on Resuscitation initiated a continuous review of new, peer-reviewed published cardiopulmonary resuscitation science. This is the fifth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations; a more comprehensive review was done in 2020. This latest summary addresses the most recently published resuscitation evidence reviewed by International Liaison Committee on Resuscitation task force science experts. Topics covered by systematic reviews in this summary include resuscitation topics of video-based dispatch systems; head-up cardiopulmonary resuscitation; early coronary angiography after return of spontaneous circulation; cardiopulmonary resuscitation in the prone patient; cord management at birth for preterm and term infants; devices for administering positive-pressure ventilation at birth; family presence during neonatal resuscitation; self-directed, digitally based basic life support education and training in adults and children; coronavirus disease 2019 infection risk to rescuers from patients in cardiac arrest; and first aid topics, including cooling with water for thermal burns, oral rehydration for exertional dehydration, pediatric tourniquet use, and methods of tick removal. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, according to the Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations or good practice statements. Insights into the deliberations of the task forces are provided in Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces listed priority knowledge gaps for further research.

Treatment of the lung injury of drowning: a systematic review

Background

Drowning is a cause of significant global mortality. The mechanism of injury involves inhalation of water, lung injury and hypoxia. This systematic review addressed the following question: In drowning patients with lung injury, what is the evidence from primary studies regarding treatment strategies and subsequent patient outcomes?

Methods

The search strategy utilised PRISMA guidelines. Databases searched were MEDLINE, EMBASE, CINAHL, Web of Science and SCOPUS. There were no restrictions on publication date or age of participants. Quality of evidence was evaluated using GRADE methodology.

Results

Forty-one papers were included. The quality of evidence was very low. Seventeen papers addressed the lung injury of drowning in their research question and 24 had less specific research questions, however included relevant outcome data. There were 21 studies regarding extra-corporeal life support, 14 papers covering the theme of ventilation strategies, 14 addressed antibiotic use, seven papers addressed steroid use and five studies investigating diuretic use. There were no clinical trials. One retrospective comparison of therapeutic strategies was found. There was insufficient evidence to make recommendations as to best practice when supplemental oxygen alone is insufficient. Mechanical ventilation is associated with barotrauma in drowning patients, but the evidence predates the practice of lung protective ventilation. There was insufficient evidence to make recommendations regarding adjuvant therapies.

Conclusions

Treating the lung injury of drowning has a limited evidentiary basis. There is an urgent need for comparative studies of therapeutic strategies in drowning.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03687-2.

Ghrelin attenuates drowning injury via dual effects on damage protection and immune repression

Background

Seawater drowning is the major cause of accidental injury and death. The current treatment could not essentially block the source of the damage due to the complex etiology. Therefore, it is urgent to clarify the detailed mechanisms and find effective therapeutic approaches.

Methods

We performed in vitro experiments to evaluate the damage of seawater drowning to lung epithelial cells. FACS, immunofluorescent staining, and western blot were used to detect the apoptosis. CCK-8 assay, Ki67 staining, and cell cycle analysis were used to assess the proliferation. The cytokine expression was determined by qRT-PCR and ELISA. Western blot and reporter assay were used for regulation mechanism study. For neutrophils development, Transwell assay and FACS were used for further investigation. Besides, in vivo study was performed with the seawater drowning model in rats.

Results

In this study, we found that seawater drowning induced mitochondria damage, which further accelerated epithelial cell apoptosis and repressed cell proliferation. Administration of ghrelin attenuated the mitochondria damage via reducing ROS generation, decreasing the concentration of calcium ion and ceremide, and promoting ATP production. Besides, exogenous ghrelin also rescued the cell survival inhibited by seawater simulants. Mechanically, ghrelin retrieved the influence of seawater via inhibiting NF-κB signaling activation, and agonist of NF-κB could offset the function of ghrelin. Besides, ghrelin reduced the expression of inflammatory factors and chemokines responsible for neutrophils activation and recruitment, by which ghrelin suppressed the immune response. The further in vivo experiments also indicated that ghrelin treatment restored the apoptosis promotion and inflammation activation function of seawater simulants, and further alleviated the lung tissue injury.

Conclusions

Our study revealed the dual effect of ghrelin on seawater drowning induced lung injury via damage protection and immune repression, providing new insights into drowning injury pathogenesis and therapeutic strategies.

Relationship between the Performance in a Maximum Effort Test for Lifeguards and the Time Spent in a Water Rescue

The main objective of this study was to analyse the relationship between the performance in a maximum incremental test for lifeguards, the IPTL, and the effectiveness of a 200 m water rescue on the beach. Initially, 20 professional lifeguards carried out the IPTL in the pool and then they performed a 200 m water rescue on the beach. The maximum oxygen uptake (VO_2max) in the IPTL was estimated. In both tests, heart rate (HR), blood lactate (La) and time achieved were measured. The VO_2max estimated in the IPTL (VO_2IPTL) was 44.2 ± 4.7 mL·kg·min⁻¹, the time reached in the IPTL (Time_IPTL) was 726 ± 72 s and the time spent in the rescue (Time_Rescue) was 222 ± 14 s. The results showed that the time reached in the pool (Time_IPTL) was the best predictor variable of the performance in water rescue (Time_Rescue) (R² = 0.59; p < 0.01). A significant correlation was also observed between the estimated maximum oxygen uptake and the beach rescue performance (R² = 0.37; p = 0.05). These results reveal that the IPTL, a maximum incremental test specific to lifeguards, allows the estimation of the effectiveness of a 200 m rescue on the beach.

Resuscitation and emergency care in drowning: A scoping review

BACKGROUND

The ILCOR Basic Life Support Task Force and the international drowning research community considered it timely to undertake a scoping review of the literature to identify evidence relating to the initial resuscitation, hospital-based interventions and criteria for safe discharge related to drowning.

METHODS

Medline, PreMedline, Embase, Cochrane Reviews and Cochrane CENTRAL were searched from 2000 to June 2020 to identify relevant literature. Titles and abstracts and if necessary full text were reviewed in duplicate. Studies were eligible for inclusion if they reported on the population (adults and children who are submerged in water), interventions (resuscitation in water/boats, airway management, oxygen administration, AED use, bystander CPR, ventilation strategies, ECMO, protocols for hospital discharge (I), comparator (standard care) and outcomes (O) survival, survival with a favourable neurological outcome, CPR quality, physiological end-points).

RESULTS

The database search yielded 3242 references (Medline 1104, Pre-Medline 202, Embase 1722, Cochrane reviews 12, Cochrane CENTRAL 202). After removal of duplicates 2377 papers were left for screening titles and abstracts. In total 65 unique papers were included. The evidence identified was from predominantly high-income countries and lacked consistency in the populations, interventions and outcomes reported. Clinical studies were exclusively observational in nature.

CONCLUSION

This scoping review found that there is very limited evidence from observational studies to inform evidence based clinical practice guidelines for drowning. The review highlights an urgent need for high quality research in drowning.

A reappraisal of childhood drowning in a pediatric emergency department

BACKGROUND

In the present study, we aimed to investigate the demographic and clinical features, laboratory and radiologic characteristics, management, and outcomes of pediatric drowning patients in order to identify predictors of hospital admission, and to evaluate the need for respiratory support, and prognosis.

METHODS

In this retrospective chart review, children aged 0 to 18 years who presented to the pediatric emergency department due to drowning between July 2009 and September 2019 were included. Demographics, initial vital signs, clinical findings, laboratory and radiologic results, and the need for respiratory support or cardiopulmonary resuscitation in the emergency department were recorded. Subjects were divided into 6 groups using the Szpilman classification system.

RESULTS

A total of 89 patients were enrolled. Among the children who were admitted to the hospital, initial Szpilman score, crepitations on lung auscultation, and pathologic chest X-ray (CXR) findings were higher and Glasgow Coma Score and oxygen saturation (SpO 2) levels were lower than those of children who were discharged from the emergency department. A Szpilman score of ≥4, a lactate level of >2 mmol/L, and pathologic CXR findings were identified as predictors of hospital admission. Of the 89 patients, 22 (24.7%) underwent non-invasive ventilation (NIV) treatment and were classified as grade 3 or 4 according to the Szpilman score. Length of stay in the pediatric intensive care unit (PICU) and in the hospital was lower in patients who underwent NIV. As the Szpilman score increased as of grade 3, a positive correlation was observed with lactate levels (p <0.001, r: 0.552) and the total length of stay in the hospital (p: 0.001, r : 0.491), both of which gradually increased.

CONCLUSION

The Szpilman score was associated with the duration of hospital stay and the degree of hypoxia, so it could help the physician make rapid decisions on ventilation strategy. Application of NIV in the emergency department shortened the length of stay in the PICU and in the hospital, suggesting that it can be used more often in pediatric emergency settings.

Proteomics in Deaths by Drowning: Diagnostic Efficacy of Apolipoprotein A1 and α-1Antitrypsin, Pilot Study

Drowning is one of the leading causes of death worldwide. The pathophysiology of drowning is complex and, sometimes, interpretation of the circumstances of death in the autopsy becomes the main source of information in its diagnosis. New advances in medical research, such as proteomics, especially in forensic pathology, are still in the development. We proposed to investigate the application of Mass Spectrometry-based technologies, to identify differentially expressed proteins that may act as potential biomarkers in the postmortem diagnosis of drowning. We performed a pilot proteomic experiment with the inclusion of two drowned and two control forensic cases. After applying restrictive parameters, we identified apolipoprotein A1 (ApoA1) and α-1 antitrypsin as differentially expressed between the two diagnostic groups. A validation experiment, with the determination of both proteins in 25 forensic cases (16 drowned and 9 controls) was performed, and we corroborated ApoA1 higher values in the drowning group, whereas α-1 antitrypsin showed lower levels. After adjusting by confounder factors, both remained as predictive independent factors for diagnosis of drowning (p = 0.010 and p = 0.022, respectively). We constructed ROC curves for biomarkers’ levels attending at the origin of death and established an ApoA1 cut-off point of 100 mg/dL. Correct classification based on the diagnosis criteria was reached for 73.9% of the cases in a discriminant analysis. We propose apolipoprotein A1 (with our cutoff value for correct classification) and α-1 antitrypsin as valuable biomarkers of drowning. Our study, based on forensic cases, reveals our proteomic approach as a new complementary tool in the forensic diagnosis of drowning and, perhaps, in clinical future implications in drowned patients. However, this is a pilot approach, and future studies are necessary to consolidate our promising preliminary data.

Nrf2 protects against seawater drowning-induced acute lung injury via inhibiting ferroptosis

Background

Ferroptosis is a new type of nonapoptotic cell death model that was closely related to reactive oxygen species (ROS) accumulation. Seawater drowning-induced acute lung injury (ALI) which is caused by severe oxidative stress injury, has been a major cause of accidental death worldwide. The latest evidences indicate nuclear factor (erythroid-derived 2)-like 2 (Nrf2) suppress ferroptosis and maintain cellular redox balance. Here, we test the hypothesis that activation of Nrf2 pathway attenuates seawater drowning-induced ALI via inhibiting ferroptosis.

Methods

we performed studies using Nrf2-specific agonist (dimethyl fumarate), Nrf2 inhibitor (ML385), Nrf2-knockout mice and ferroptosis inhibitor (Ferrostatin-1) to investigate the potential roles of Nrf2 on seawater drowning-induced ALI and the underlying mechanisms.

Results

Our data shows that Nrf2 activator dimethyl fumarate could increase cell viability, reduced the levels of intracellular ROS and lipid ROS, prevented glutathione depletion and lipid peroxide accumulation, increased FTH1 and GPX4 mRNA expression, and maintained mitochondrial membrane potential in MLE-12 cells. However, ML385 promoted cell death and lipid ROS production in MLE-12 cells. Furthermore, the lung injury became more aggravated in the Nrf2-knockout mice than that in WT mice after seawater drowning.

Conclusions

These results suggested that Nrf2 can inhibit ferroptosis and therefore alleviate ALI induced by seawater drowning. The effectiveness of ferroptosis inhibition by Nrf2 provides a novel therapeutic target for seawater drowning-induced ALI.

Drowning Classification: A Reappraisal of Clinical Presentation and Prognosis for Severe Cases

BACKGROUND

Drowning is still a major cause of accidental death worldwide. In 1997, Szpilman proposed a classification of drowning that has become the reference. As considerable efforts have been made to improve prevention and care, it seemed appropriate to reassess the prognosis and clinical presentation of drowning patients more than 20 years after this first publication. The aim of this study is to provide a reappraisal of patients who need advanced health care and a precise description of their respective neurologic, respiratory, and hemodynamic profiles.

METHODS

This retrospective study was conducted over four consecutive summer periods between 2014 and 2017 in ICUs located in France, French Polynesia, and the French Antilles. Patients were classified according to the drowning classification system proposed by Szpilman.

RESULTS

During the study period, 312 drowning patients were admitted with severe clinical presentation (grades 2-6). All patients benefited from rapid extraction from the water (< 10 min for all) and specialized care (emergency medical services), starting from the prehospital period. Although the global hospital mortality was similar to that previously reported (18.5%), great differences existed among the severity grades. Respective grade mortalities were low for grades 2 through 5 (grade 2, 0%; grade 3, 3%; grade 4, 0%; grade 5, 2%), and the mortality for grade 6 remained similar to that previously reported (54%). These results confirmed that the occurrence of cardiac arrest after drowning is still bad prognosis. Conversely, for other grades, this study strengthens the importance of specialized intervention to interrupt the drowning process.

CONCLUSIONS

On the basis of these results, drowning-related cardiac arrest is still the prognosis cornerstone. For other victims, the prognosis was better than previously expected, which strengthens the importance of specialized intervention to interrupt the drowning process.

Drowning in fresh or salt water: respective influence on respiratory function in a matched cohort study

INTRODUCTION

For the most severe drowned patients, hypoxemia represents one of the major symptoms. As the influence of the type of water (fresh or salt water) on respiratory function is still unclear, the primary endpoint of this multicenter study was to compare hypoxemia according to the type of water.

METHODS

Medical records of adult patients who experienced a drowning event and were consequently admitted to 10 ICU for acute respiratory failure were analyzed retrospectively using data collected over three consecutive summer periods. From an initial cohort of acute respiratory failure drowned patients, patients were matched by age, sex, Glasgow Coma Scale, and occurrence of cardiac arrest (yes or no).

RESULTS

Among an initial cohort of 242 patients, 38 pairs were matched correctly. At the initial assessment, carried out upon ICU admission, hypoxemia was found to be deeper in the fresh water group (PaO2/FiO2: 141 ± 76 vs. 220 ± 122, P < 0.05). However, there was no significant difference in tissue oxygenation (assessed by blood lactate level) between groups. In terms of biology results, sodium levels were higher in the salt water group in the initial assessment (144 ± 6.8 vs. 140 ±5.2 mmol/l, P = 0.004), but no difference was observed later. No difference was recorded in the outcome or length of stay in ICU between groups.

CONCLUSION

Drowning in fresh water was associated with deeper hypoxemia in the initial assessment. Despite this initial difference, latter respiratory and biological parameters or outcome were similar in both groups.

Imaging findings of pulmonary edema: Part 2. Infrequent or unusual pulmonary edema with definitive imaging findings

Pulmonary edema is a common condition with numerous causes, some of which are infrequently encountered. This review article describes various uncommon conditions/disease that are associated with pulmonary edema and which show characteristic imaging findings on chest computed tomography or other imaging modality. Thus, this review reflects the variety of factors involved in this frequently encountered condition. We demonstrate the wide range of situations that lead to the development of pulmonary edema by showing the imaging findings of unique cases. These rare varieties of pulmonary edema have distinctive imaging and clinical features that aid in providing an accurate diagnosis.

Wilderness Medical Society Clinical Practice Guidelines for the Treatment and Prevention of Drowning: 2019 Update

The Wilderness Medical Society convened a panel to review available evidence supporting practices for acute management and treatment of drowning in out-of-hospital and emergency medical care settings. Literature about definitions and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded available evidence supporting practices according to the American College of Chest Physicians criteria and then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking. This is the first update to the original practice guidelines published in 2016.

Heme oxygenase-1 attenuates seawater drowning-induced acute lung injury through a reduction in inflammation and oxidative stress

OBJECTIVE

Heme oxygenase-1 (HO-1) plays a critical protective role in various insults-induced acute lung injury (ALI) through its strong anti-inflammatory, anti-oxidant, and anti-apoptotic properties, but its protective role and mechanism on seawater aspiration-induced acute lung injury remains unclear. This study aimed to explore the therapeutic potential and mechanism of HO-1 to attenuate seawater aspiration-induced ALI in vivo and in vitro.

METHODS

The viability and invasion of A549 cell were analyzed through cell counting kit-8 and lactate dehydrogenase release assay; the transcriptional level of inflammatory cytokines (TNF-α, IL-6, IL-8 and MCP-1) and cell proliferation-related cytokines (FoxM1, Ccnb1 and Cdc25C) in seawater-treated A549 cell were tested by qPCR; apoptotic cells were analyzed by flow cytometryd; HO-1mRNA and protein were determined by qPCR and western blotting; the fluorescent indicators (DCFH-DA, dihydroethidium, MitoSox Red and Fluo-4) were used to monitor generation of ROS and mitochondrial function. The lung wet/dry weight radio and lactate dehydrogenase activity, Sirius red staining, TUNEL assay and immunohistochemical staining with anti-pan Cytokeratin antibody were analyzed in seawater-drowning mice. The role of HO-1 on seawater-drowning pulmonary injury was explored via HO-1 activity inhibitors (Zinc protoporphyrin) in vitro and in vivo.

RESULTS

Seawater exposure decreased the cellular viability, increased the production of pro-inflammatory cytokines (IL-6, IL-8 and TNF-α), induced cellular apoptosis and inhibited the expression of cell proliferation-related cytokines (FoxM1, Ccnb1 and Cdc25C). Moreover, seawater exposure led to mitochondrial dysfunction in A549 cells. Supplement of HO-1 sepcific inducer (heme) or its catalytic product (biliverdin) significantly attenuated seawater-induced A549 damage and promoted cell proliferation. However, Zinc protoporphyrin abolished the beneficial effects of HO-1 on seawater drowning-induced pulmonary tissue injury.

CONCLUSION

HO-1 attenuates seawater drowning-induced lung injury by its anti-inflammatory, anti-oxidative, and anti-apoptosis function.

Acute respiratory failure after drowning: a retrospective multicenter survey

OBJECTIVES

Despite the extensive literature on drowning, clinical data are still lacking on the best medical strategy to use. Acute respiratory failure (ARF) is the main component of drowning pathophysiology. The objectives of this multicenter study were to analyze the clinical course of drowning-related ARF patients and to describe the efficacy of the ventilatory strategies used.

METHODS

Medical records of drowned adult patients admitted in seven ICUs after prehospital emergency medical care during three consecutive summer periods were retrospectively analyzed.

RESULTS

Among the 126 patients (58±21 years) admitted, 38 patients with cardiac arrest at the scene were not analyzed, 26 received mechanical ventilation (MV), and 48 patients received noninvasive ventilation (NIV). Compared with patients placed under MV, the NIV patients presented a better initial neurological (Glasgow Coma Scale of 7±4 vs. 12±3, P<0.05) and hemodynamic status from the prehospital stage (mean arterial pressure of 77±18 vs. 96±18, P<0.001). With comparable ARF-related hypoxemia to MV, the NIV was maintained with success in 92% (44/48). Both MV and NIV were associated with rapid improvement of oxygenation and short ICU length of stay [3 (1-14) and 2 (1-7), respectively].

CONCLUSION

Despite the absence of recommendation for NIV use in case of drowning-related ARF, this technique was often used with safety and efficacy. The decision for NIV use was mainly based on the preserved or improved neurological status.

3,5,4'-Tri-O-acetylresveratrol attenuates seawater inhalation-induced acute respiratory distress syndrome via thioredoxin 1 pathway

The protecting effects of 3,5,4'-tri-O-acetylresveratrol (AC-Res) on seawater inhalation-induced acute respiratory distress syndrome (ARDS) by interfering with the activation of thioredoxin-1 (Trx-1) pathway were evaluated. Seawater inhalation-induced ARDS was assessed by magnitude of pulmonary edema and lung inflammation. Oxidative stress was tested by T-SOD activity and MDA content in lungs and cells. Besides, Trx-1, nuclear factor erythroid 2-related factor 2 (Nrf2) and Txnip expression were measured to explore how seawater induced oxidative stress and the mechanism by which AC-Res attenuated seawater inhalation-induced ARDS. The results showed that seawater inhalation increased wet-to-dry (W/D) ratios of lung tissues, enhanced secretion of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and disturbed the oxidative distress balance probably through interfering the activity of Trx-1 pathway. While treatment of AC-Res in vivo and Res in vitro reduced W/D ratios of lung tissues, decreased cytokines in lungs and maintained the oxidative stress balance through Trx-1 pathway. In conclusion, AC-Res treatment attenuated seawater inhalation induced ARDS via Trx-1 pathway.

Efficacy of Early Noninvasive Ventilation in Three Cases of Nonfatal Drowning with Pulmonary Oedema in the Paediatric Emergency Department

Drowning is still one of the most important causes of the preventable mortality worldwide. Some patients should be treated with noninvasive ventilation immediately in the emergency department (ED). The practice of noninvasive ventilation has been increased recently in the paediatric ED. We present here three nonfatal drowning patients with pulmonary oedema and hypoxia who were successfully treated with noninvasive ventilation in the paediatric emergency department. All of the patients had aspirated sea water during swimming. In addition, two of the patients had aspirated water during snorkeling. Noninvasive ventilation was applied to the patients immediately in paediatric emergency service. All of the patient's clinical and radiological findings recovered rapidly. There are limited reports about use of noninvasive ventilation in nonfatal drowning cases in the paediatric emergency department. We emphasize that the early application of noninvasive ventilation should be a preventive method for reducing the morbidity of nonfatal drowning cases. (Hong Kong j.emerg.med. 2016;23:42-46)

Cognitive performance in transient global hypoxic brain injury due to moderate drowning

INTRODUCTION

Drowning is a serious and frequently neglected public health threat. Primary respiratory impairment after submersion often leads to brain dysfunction. Depending on the period of global hypoxia (respiratory failure), clinical aspects of neurological dysfunction are evident on the first evaluation after the water rescue. Nowadays, many neuropsychological assessments after drowning are inconclusive, with some studies reporting only minor neurological or cognitive impairments. The aim of this study is to identify measures in neuropsychological tests that most contribute to classify volunteers as moderate drowning subjects or healthy controls. To the best of our knowledge, this study is the first neuropsychological prospective case-control study of moderate drowning in a country with large coastal cities.

METHOD

Fifteen moderate drowning patients (DP), who met the inclusion criteria, were compared with 18 healthy controls (HC). All subjects were assessed on memory, learning, visual spatial ability, executive function, attention, and general intellectual functioning and underwent structural magnetic resonance (MR) imaging of the brain at 3.0 T, in order to exclude subjects with anatomic abnormalities.

RESULTS

Neuropsychological tests assessing learning, execution function, and verbal fluency-Rey Auditory Verbal Learning Test (RAVLT) general learning ability, Digit Span total, Phonological Verbal Fluency (total FAS correct), and Brief Visuospatial Memory Test Revised (BVMT) correct recognition-have the strongest discriminating ability, using predictive models via the partial least squares (PLS) approach for data classification, while the other tests have shown similar predictive values between groups.

CONCLUSIONS

Learning, execution function, and verbal fluency domains were the most critically affected domains. Serious impairments in the same domains have already been reported in severe drowning cases, and we hypothesize that subtle alterations found in moderate drowning cases, although not sufficient to be detected in daily routine, may possibly have a negative impact on cognitive reserve.

Losartan, a selective antagonist of AT1 receptor, attenuates seawater inhalation induced lung injury via modulating JAK2/STATs and apoptosis in rat

Losartan is a selective antagonist of AngⅠ type (AT1) receptor of Angiotensin Ⅱ (Ang Ⅱ), which is widely used as a clinical medicine for the hypertension. Recent studies have shown that losartan was shown to protect from acute lung injury (ALI). However, the underlying mechanism remains unclear. The aim of this research was to clarify whether Ang Ⅱ participated in the inflammatory response of ALI induced by seawater inhalation, and whether losartan had the protective effects on ALI by blocking the combination of Ang Ⅱ and AT1 receptor. In the current study, the severity of lung injury and the inflammatory reactions during seawater drowning induced ALI were assessed. Besides, we also detected the activation of relative pathways such as NF-κB, JAK2/STATs and apoptosis. The results showed that seawater inhalation could up-regulate the expression of Ang Ⅱ and AT1. While pretreatment of losartan (especially 15 mg/kg and 30 mg/kg) alleviated lung injury by inhibiting Ang-Ⅱ and AT1 receptor combination and in turn decreased the expression of p-NF-κB and activation of JAK2/STATs pathway. We also confirmed that losartan could reduce the apoptotic ratio of cells in the lung by modulating the phosphorylation of JNK and leak of cytochrome C to cytosol. Taken together, these findings demonstrate that losartan might have a therapeutic potential as an anti-inflammatory agent for treating SWI-ALI.

Seawater-drowning-induced acute lung injury: From molecular mechanisms to potential treatments

Drowning is a crucial public safety problem and is the third leading cause of accidental fatality, claiming ~372,000 lives annually, worldwide. In near-drowning patients, acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is one of the most common complications. Approximately 1/3 of near-drowning patients fulfill the criteria for ALI or ARDS. In the present article, the current literature of near-drowning, pathophysiologic changes and the molecular mechanisms of seawater-drowning-induced ALI and ARDS was reviewed. Seawater is three times more hyperosmolar than plasma, and following inhalation of seawater the hyperosmotic seawater may cause serious injury in the lung and alveoli. The perturbing effects of seawater may be primarily categorized into insufficiency of pulmonary surfactant, blood-air barrier disruption, formation of pulmonary edema, inflammation, oxidative stress, autophagy, apoptosis and various other hypertonic stimulation. Potential treatments for seawater-induced ALI/ARDS were also presented, in addition to suggestions for further studies. A total of nine therapeutic strategies had been tested and all had focused on modulating the over-activated immunoreactions. In conclusion, seawater drowning is a complex injury process and the exact mechanisms and potential treatments require further exploration.

Physiology Of Drowning: A Review

Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.

Pneumonia, Acute Respiratory Distress Syndrome, and Early Immune-Modulator Therapy

Acute respiratory distress syndrome (ARDS) is caused by infectious insults, such as pneumonia from various pathogens or related to other noninfectious events. Clinical and histopathologic characteristics are similar across severely affected patients, suggesting that a common mode of immune reaction may be involved in the immunopathogenesis of ARDS. There may be etiologic substances that have an affinity for respiratory cells and induce lung cell injury in cases of ARDS. These substances originate not only from pathogens, but also from injured host cells. At the molecular level, these substances have various sizes and biochemical characteristics, classifying them as protein substances and non-protein substances. Immune cells and immune proteins may recognize and act on these substances, including pathogenic proteins and peptides, depending upon the size and biochemical properties of the substances (this theory is known as the protein-homeostasis-system hypothesis). The severity or chronicity of ARDS depends on the amount of etiologic substances with corresponding immune reactions, the duration of the appearance of specific immune cells, or the repertoire of specific immune cells that control the substances. Therefore, treatment with early systemic immune modulators (corticosteroids and/or intravenous immunoglobulin) as soon as possible may reduce aberrant immune responses in the potential stage of ARDS.

NFAT5 participates in seawater inhalation‑induced acute lung injury via modulation of NF-κB activity

Nuclear factor of activated T cells 5 (NFAT5) is a transcription factor that can be activated by extracellular tonicity. It has been reported that NFAT5 may increase the transcription of certain osmoprotective genes in the renal system, and the aim of the current study was to explore the role of NFAT5 in seawater inhalation-induced acute lung injury. Though establishing the model of seawater inhalation-induced acute lung injury, it was demonstrated that seawater inhalation enhanced the transcription and protein expression of NFAT5 (evaluated by reverse transcription-polymerase chain reaction, immunohistochemistry stain and western blotting) and activation of nuclear factor (NF)-κB (evaluated by western blotting and mRNA expression levels of three NF-κB-dependent genes) both in lung tissue and rat alveolar macrophage cells (NR8383 cells). When expression of NFAT5 was reduced in NR8383 cells using an siRNA targeted to NFAT5, the phosphorylation of NF-κB and transcription of NF-κB-dependent genes were significantly reduced. In addition, the elevated content of certain inflammatory cytokines [tumor necrosis factor α, interleukin (IL)-1 and IL-8] were markedly reduced. In conclusion, NFAT5 serves an important pathophysiological role in seawater inhalation-induced acute lung injury by modulating NF-κB activity, and these data suggest that NFAT5 may be a promising therapeutic target.

Radiologic, Neurologic and Cardiopulmonary Aspects of Submersion Injury

Many indices and scores are used in critical care medicine to aid management and predict risk of mortality. We report 2 cases of submersion injury and discuss the usefulness and application of common respiratory and critical care indices. The respiratory indices help better understand the pulmonary pathophysiology and characterize the severity of lung injury and ventilation/perfusion mismatch. Severe lung injury resolved after ventilation support with appropriate positive end-expiratory pressure in both cases. The 6-year-old girl survived the near-fatal submersion injury intact despite grossly abnormal initial Glasgow Coma Scale (GCS) and high Pediatric Index of Mortality 2 scores, whereas the 5-year-old boy with grossly abnormal GCS and Pediatric Index of Mortality 2 scores died despite resolution of lung injury. These cases illustrate that resuscitation should be promptly instituted at the scene to ensure optimal outcome because initial pulmonology and neurology indices may not reliably predict mortality or intact survival. The GCS score was not initially designed for prognostication. Nevertheless, 2 serial GCS scores of 3, one performed at emergency department and one at the pediatric intensive care unit, were associated with nonsurvival in our second patient.

Identification of distinct genes associated with seawater aspiration‑induced acute lung injury by gene expression profile analysis

Seawater aspiration-induced acute lung injury (ALI) is a syndrome associated with a high mortality rate, which is characterized by severe hypoxemia, pulmonary edema and inflammation. The present study is the first, to the best of our knowledge, to analyze gene expression profiles from a rat model of seawater aspiration-induced ALI. Adult male Sprague-Dawley rats were instilled with seawater (4 ml/kg) in the seawater aspiration-induced ALI group (S group) or with distilled water (4 ml/kg) in the distilled water negative control group (D group). In the blank control group (C group) the rats' tracheae were exposed without instillation. Subsequently, lung samples were examined by histopathology; total protein concentration was detected in bronchoalveolar lavage fluid (BALF); lung wet/dry weight ratios were determined; and transcript expression was detected by gene sequencing analysis. The results demonstrated that histopathological alterations, pulmonary edema and total protein concentrations in BALF were increased in the S group compared with in the D group. Analysis of differential gene expression identified up and downregulated genes in the S group compared with in the D and C groups. A gene ontology analysis of the differential gene expression revealed enrichment of genes in the functional pathways associated with neutrophil chemotaxis, immune and defense responses, and cytokine activity. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the cytokine-cytokine receptor interaction pathway was one of the most important pathways involved in seawater aspiration-induced ALI. In conclusion, activation of the cytokine-cytokine receptor interaction pathway may have an essential role in the progression of seawater aspiration-induced ALI, and the downregulation of tumor necrosis factor superfamily member 10 may enhance inflammation. Furthermore, IL-6 may be considered a biomarker in seawater aspiration-induced ALI.

The Role of Phosphorylated Cx43 on PKC Mediated Ser368 in Lung Injury Induced by Seawater Inhalation

Seawater aspiration may result in acute lung injury/acute respiratory distress syndrome (ALI/ARDS), which is characterized by pulmonary inflammation and lung edema that closely related to pulmonary barrier dysfunction and intracellular communication. The aim of the present research was to explore the role of connexion 43 (Cx43) in seawater aspiration-induced ALI/ARDS. The results from in vivo experiments showed that seawater inhalation led to increased expression of p-PKC and phosphorylated Cx43 (p-Cx43), which were followed by protein rich fluid leakage and TNF-α and IL-1β secretion. Besides, the results from in vitro tests proved that the expression of p-PKC directly influenced phosphorylation state of Cx43 and its function, which could further affect the inflammatory factors secretion and intercellular communication. In conclusion, seawater aspiration causes p-Cx43 expression by PKC pathway, which is involved in the on come and development of pulmonary inflammation and lung edema.

Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Drowning

The Wilderness Medical Society convened a panel to review available evidence supporting practices for the prevention and acute management of drowning in out-of-hospital and emergency medical care settings. Literature about definition and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded evidence supporting practices according to the American College of Chest Physicians criteria, then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking.

3,5,4'-Tri-O-acetylresveratrol decreases seawater inhalation-induced acute lung injury by interfering with the NF-κB and i-NOS pathways

Drowning is a cause of accidental mortality. However, survival may result in acute lung injury. The aim of the present study was to evaluate the effects of 3,5,4'-tri-O-acetylresveratrol (AC-Res) on acute lung injury (ALI) induced by seawater inhalation in rats. ALI models were established by the tracheal instillation of artificial seawater with or without 50 mg/kg AC-Res pretreatment for 7 days. Lung samples from different groups were harvested 4 h after the model was established. Histological changes, blood vessel permeability, inflammatory factor secretion and expression states of the nuclear factor-κB (NF-κB) and inducible NOS (i-NOS) pathway were assessed to evaluate seawater‑induced lung injury and the protective effects of acetylated resveratrol. The results showed that seawater inspiration led to physiological structure changes and an increased permeability of blood vessels. In addition, seawater stimulation enhanced the expression levels of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin-1 β (IL-1β) secretion in vitro and in vivo. Notably, seawater inhalation increased NF-κB and i-NOS expression in lungs and cells. On the other hand, pretreatment of AC-Res inhibited the abnormal expression of the NF-κB and i-NOS pathways, followed by decreased NO, TNF-α and IL-1β secretion, protein and cell content in bronchoalveolar lavage fluid (BALF) and Evans blue, protein and cell infiltration from blood vessels into lung tissues. The results therefore suggest that AC-Res attenuated seawater inhalation induced‑ALI by interfering with the NF-κB and i-NOS pathways.

Seawater immersion aggravates sciatic nerve injury in rats

The aim of the present study was investigate the impact of seawater immersion on peripheral nerve injury and the underlying mechanisms. A total of 234 specific pathogen-free Sprague-Dawley male rats were randomly divided into a sham group, injury control group and seawater immersion + injury group. The Sciatic Functional Index (SFI) was used to assess nerve function for 6 weeks after injury. Compound muscle action potentials were measured and hematoxylin and eosin (H&E) staining of nerve specimens was carried out at week 6. Levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in nerve tissues were measured by enzyme-linked immunosorbent assay (ELISA), and the expression levels of inducible nitric oxide synthase (iNOS) mRNA and protein were measured by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, respectively. The SFI value in the seawater immersion + injury group after 6 weeks was lower than that in the injury control group (P<0.05). The compound muscle action potential in the seawater immersion + injury group had a prolonged latency, and the amplitude and nerve conduction velocity were decreased compared with those in the other groups (P<0.05). H&E staining demonstrated that nerve fiber regeneration was worse in the seawater immersion + injury group. The ROS and MDA levels in the seawater immersion + injury group were higher than those in the other groups (P<0.05). The expression levels of iNOS mRNA and protein gradually increased in the injury and seawater immersion + injury groups and peaked at 48 h after surgery. Immersion in seawater further aggravated sciatic nerve injury and led to worse neuronal recovery. The mechanism may be associated with oxidative stress.

High fever and multi-nodular lung consolidations after whole lung lavage in a patient with pulmonary alveolar proteinosis

Introduction

Whole lung lavage is the most effective method to treat pulmonary alveolar proteinosis (PAP), and most potential complications occur often during the lavage process, but few happen after lavage. Theoretically, pulmonary edema would be more common after whole lung lavage. However, no such case was reported in the literature.

Case description

A 47-year-old Chinese male patient with PAP was referred to our hospital for whole lung lavage treatment. Although the clinical manifestations of PAP were improved, high fever was happened and multi-nodular consolidations in chest CT scan were occurred after whole lung lavage. Secondary lung infection was suspected, but the patient was not treated with antibiotics immediately. After therapies like liquid limitation, glucocorticoid administration and diuretic treatment, the patient was improved gradually. Namely, newly nodular consolidations were almost completely absorbed in three days, along with the complete recovery of body temperature and associated inflammatory biomarkers. The diagnosis of secondary infection was excluded, and the final diagnosis of lavage fluid-induced pulmonary edema was confirmed.

Discussion and evaluation

No such case has been reported that lavage fluid-induced pulmonary edema is manifested by high fever and multi-consolidations in chest CT scan, which is similar to the secondary infection.

Conclusions

For the first time, we described a rare complication of lavage fluid-induced pulmonary edema after whole lung lavage. As the obvious differences in treatments, it is very important for physicians to differentiate it from secondary infection.

Blood alcohol content, injury severity, and adult respiratory distress syndrome

BACKGROUND

Elevated blood alcohol content (BAC) is a risk factor for injury. Associations of BAC with adult respiratory distress syndrome (ARDS) have not been conclusively established.We evaluated the association of a BAC greater than 0 mg/dL with the intermediate outcomes, Injury Severity Score (ISS) and Glasgow Coma Scale (GCS) score, and their association with ARDS development.

METHODS

This is an observational retrospective cohort study of 26,305 primary trauma admissions to a statewide referral trauma center from July 11, 2003, to October 31, 2011. Logistic regression was performed to assess the relationship between admission BAC, ISS, GCS score, and ARDS development within 5 days of admission.

RESULTS

The case rate for ARDS was 5.5% (1,447). BAC greater than 0 mg/dL was associated with ARDS development in adjusted analysis (odds ratio, 1.50; 95% confidence interval [CI], 1.33-1.71; p < 0.001). High ISS (≥16) had a stronger association with ARDS development (odds ratio, 17.99; 95% CI, 15.51-20.86), as did low GCS score (≤8) (odds ratio, 8.77; 95% CI, 7.64-10.07; p < 0.001). Patients with low GCS score and high ISS had the most frequent ARDS (33.6%) and the highest case-fatality rate without ARDS (24.7%).

CONCLUSION

Elevated BAC is associated with ARDS development. In the analysis of alcohol exposure, ISS and GCS score occur after alcohol ingestion, making them intermediate outcomes. ISS and GCS score were strong predictors of ARDS and may be useful to identify at-risk patients. Elevated BAC may increase the frequency of the ARDS through influence on injury severity or independent molecular mechanisms, which can be discriminated only in experimental models.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Epigallocatechin-3-gallate ameliorates seawater aspiration-induced acute lung injury via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats

Signal transducers and activators of transcriptions 1 (STAT1) play an important role in the inflammation process of acute lung injury (ALI). Epigallocatechin-3-gallate (EGCG) exhibits a specific and strong anti-STAT1 activity. Therefore, our study is to explore whether EGCG pretreatment can ameliorate seawater aspiration-induced ALI and its possible mechanisms. We detected the arterial partial pressure of oxygen, lung wet/dry weight ratios, protein content in bronchoalveolar lavage fluid, and the histopathologic and ultrastructure staining of the lung. The levels of IL-1, TNF-α, and IL-10 and the total and the phosphorylated protein level of STAT1, JAK1, and JAK2 were assessed in vitro and in vivo. The results showed that EGCG pretreatment significantly improved hypoxemia and histopathologic changes, alleviated pulmonary edema and lung vascular leak, reduced the production of TNF-α and IL-1, and increased the production of IL-10 in seawater aspiration-induced ALI rats. EGCG also prevented the seawater aspiration-induced increase of TNF-α and IL-1 and decrease of IL-10 in NR8383 cell line. Moreover, EGCG pretreatment reduced the total and the phosphorylated protein level of STAT1 in vivo and in vitro and reduced the phosphorylated protein level of JAK1 and JAK2. The present study demonstrates that EGCG ameliorates seawater aspiration-induced ALI via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats.

3,5,4'-tri-O-acetylresveratrol ameliorates seawater exposure-induced lung injury by upregulating connexin 43 expression in lung

The aim of the present study was to examine the effects of 3,5,4'-tri-O-acetylresveratrol on connexin 43 (Cx43) in acute lung injury (ALI) in rats induced by tracheal instillation of artificial seawater. Different doses (50, 150, and 450 mg/kg) of 3,5,4'-tri-O-acetylresveratrol were administered orally for 7 days before modeling. Four hours after seawater inhalation, histological changes, contents of TNF- α , IL-1 β and IL-10, and the expression of Cx43 in lungs were detected. Besides, the gap junction communication in A549 cells and human umbilical vein endothelial cells (HUVECs) challenged by seawater was also evaluated. Histological changes, increased contents of inflammatory factors, upregulation in gene level, and deregulation in protein level of Cx43 in lungs stimulated by seawater were observed. On the other hand, pretreatment with 3,5,4'-tri-O-acetylresveratrol significantly inhibited infiltration of inflammation, development of pulmonary edema, and contents of inflammatory mediators in lungs. Above all, 3,5,4'-tri-O-acetylresveratrol upregulated the expression of Cx43 in both gene and protein levels, and its intermediate metabolite, resveratrol, also enhanced the gap junction communication in the two cell lines. The results of the present study suggested that administration of 3,5,4'-tri-O-acetylresveratrol may be beneficial for treatment of inflammatorycellsin lung.

Journey of a survivor of near drowning, polymicrobial pneumonia, and acute respiratory distress syndrome

This article discusses a woman who collapsed and landed in a puddle of water in a park near a horse trail. Her rescue and resuscitation started an extraordinary effort by her body to heal from multiple insults. This case study highlights the diagnosis and support of polymicrobial pneumonia secondary to near drowning and the multisystem complications throughout the 3-month hospitalization. It highlights the evidence for treatment of the polymicrobial nature of submersion injury, acute lung injury, and benefits of progressive mobility. Social media as a tool for the family's communication and coping are also discussed.