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Diving and Hyperbaric Medicine Jun 2021The Centre de Médecine de Plongée du Québec (CMPQ) established a bilingual 24-hour dive emergency call line and diving medicine information service in 2004. The... (Review)
Review
INTRODUCTION
The Centre de Médecine de Plongée du Québec (CMPQ) established a bilingual 24-hour dive emergency call line and diving medicine information service in 2004. The toll-free number (888-835-7121) works throughout Canada. Calls and emails ([email protected]) are answered by a CMPQ coordinator or on-call hyperbaric physicians and other consultants as needed. We reviewed 15 years of activity.
METHODS
Details of phone calls and email enquiries to the centre were reviewed individually and compiled into a database. Data were analysed to characterise contact volume and issues addressed. Contacts were categorised into five groups: information only (INF); medical opinion required (MOP); medical issue after the critical period of urgency had passed (PUR); current urgent but not immediate life-threatening issue (NLT); and immediate life- or health-threatening issue (ILT). Data presented as mean (standard deviation) or percentage.
RESULTS
A total of 3,232 contacts were made from May 2004 through December 2018: 19 (SD 8) per month [215 (70) per year]. Primary issues of concern were: emergency planning (20%); technical (not medical/physiology) questions (16%); otorhinolaryngological (12%); and decompression sickness-related (7%). Categorisation was 52% INF, 28% MOP, 13% PUR, 7% NLT, and 0.1% ILT, with 0.2% lacking sufficient detail to categorise. The nature of the diving activity of interest was determined in 67% of cases: 48% (n = 1,039) professional; 46% (n = 1,008) recreational; and 1% (n = 11) breath-hold.
CONCLUSIONS
The call centre serves as a resource to the community, providing information on health and safety for diving in addition to being available to assist with emergent needs.
Topics: Call Centers; Canada; Decompression Sickness; Diving; Humans; Quebec; Retrospective Studies
PubMed: 34157730
DOI: 10.28920/dhm51.2.152-160 -
British Dental Journal Jan 2023Background and aim Dental tourism, which reflects the provision of health care services abroad, also includes a travelling component. Air travel after dental...
Background and aim Dental tourism, which reflects the provision of health care services abroad, also includes a travelling component. Air travel after dental intervention may cause barotrauma and barodontalgia. This paper aimed to provide guiding principles regarding the minimal time interval between dental procedures and air travel to prevent these adverse effects.Methods A literature search was performed to reveal information with regards to complications related to flights following dental treatments. There is little research in this area and most of it has been conducted on the military aircrew population, which has different characteristics of flight and personnel than civilian commercial flights.Results The recommended time of flying is one week after most dental intervention and six weeks after a sinus lift procedure. The minimal time required between a procedure and flight is 24 hours after restorative treatment, 24-48 hours after simple extraction, 72 hours after nonsurgical endodontic procedure, surgical extraction, and implant placement, and at least two weeks after sinus lift procedure.Conclusions The provided guidelines may serve as a starting point for the clinician's decision-making. The tailoring of an individual treatment plan to the patient should take into consideration the patient's condition, dental procedure, complications and flight characteristics. Further research based on commercial flights is needed to formulate more accurate guidelines for the civilian population.
Topics: Humans; Aerospace Medicine; Barotrauma; Diving; Toothache; Dental Caries; Stomatognathic Diseases; Medical Tourism; Atmospheric Pressure
PubMed: 36707585
DOI: 10.1038/s41415-023-5449-x -
Injury Apr 2022Eye injuries comprise 10-13% of civilian improvised explosive device (IED) injuries. The bomb blast wave induces a normal and shear forces on the tissues, causing a...
BACKGROUND
Eye injuries comprise 10-13% of civilian improvised explosive device (IED) injuries. The bomb blast wave induces a normal and shear forces on the tissues, causing a large acute IOP elevation. This study calculated the biomechanical stresses and strains in the eye due to IED explosion via eye-specific fluid-structure interaction (FSI) models.
METHODS
Blast occurred at 2, 3, and 4 m from the front and side of the victim and the weights of the IED were 1 and 2 kg. The ground was covered with the deformable soil to mimic the realistic IED explosion condition and reflect the blast wave.
RESULTS
The IOP elevation of ∼6,000-48,000 mmHg was observed in the eyes while the highest IOP was occurred with the IED weight and distance of 2 kg and 2 m (front) and the lowest was occurred with the IED weight and distance of 1 kg and 4 m (side). Our findings suggest the importance of the victim location and orientation concerning the blast wave when it comes to ocular injury assessment. IOP elevation of ∼2900 and ∼2700 mmHg were observed in ∼1.6 ms after the blast for the IEDS weight of 2 kg and a victim distance of 2 m in front and side blasts, respectively, in consistence with the literature. Nonetheless, IOPs were considerably higher after ∼1.6 ms due to the merging of the bomb blast wave and its reflection off the ground.
CONCLUSIONS
The stresses and strains were highest for the frontal blast. Both side and frontal blasts caused higher stresses and strains at the rectus muscle insertions where the sclera is thinnest and prone to rupture. Blast angle has no considerable role in the resultant IOP. Front blast with a heavier IED resulted a higher stresses and deformations in the eye connective tissues compared to the side blast.
Topics: Biomechanical Phenomena; Blast Injuries; Bombs; Explosions; Humans; Sclera
PubMed: 35144807
DOI: 10.1016/j.injury.2022.02.008 -
Critical Care Medicine Mar 2022
Topics: Barotrauma; COVID-19; Humans; Respiratory Distress Syndrome; SARS-CoV-2
PubMed: 34380943
DOI: 10.1097/CCM.0000000000005291 -
Diving and Hyperbaric Medicine Jun 2019In this issue, Anderson and colleagues report follow-up of divers who were found to have a persistent (patent) foramen ovale (PFO) or, in eleven cases, an atrial septal...
In this issue, Anderson and colleagues report follow-up of divers who were found to have a persistent (patent) foramen ovale (PFO) or, in eleven cases, an atrial septal defect (ASD). In most divers diagnosis followed an episode of decompression illness (DCI). The efficacy of closure of the PFO/ASD in preventing future DCI was compared with conservative diving. They reported that in the closure group the occurrence of confirmed DCI decreased significantly compared with pre-closure, but in the conservative group this reduction was not significant. It is believed there are three requirements for a diver to suffer shunt-mediated DCI: A significant right-to-left shunt (usually a large PFO but sometimes an ASD or pulmonary arteriovenous malformation). Venous bubbles nucleated during decompression circumvent the lung filter by passing through the shunt. Target tissues are supersaturated with dissolved inert gas, so that they are able to amplify embolic bubbles. All three are required because DCI does not occur after contrast echocardiography when bubbles cross a right-to-left shunt. Therefore, there are two ways that a diver who has suffered shunt-mediated DCI may continue to dive - either their shunt is sealed or future dives should be so conservative that venous bubbles are not liberated and/or critical tissues are not able to amplify embolic bubbles. PFO/ASD closure will give divers a risk of DCI comparable to the risk in others without a right-to-left shunt, if the procedure adequately seals the shunt. Closure of the shunt will not prevent a diver suffering DCI by other mechanisms, such as when there is arterial gas embolism (AGE) as a result of pulmonary barotrauma or when the dive profile is provocative (e.g., if there is rapid ascent or missed decompression stops). Conservative diving will be effective only if all the dives performed are truly conservative and prevent bubble nucleation and/or amplification. The study by Anderson et al. has a number of serious limitations. The study was small with only 62 self-selected divers, who self-reported outcomes. Eleven divers had not had DCI when their PFO or ASD was detected. Initially 36 divers were classified as closure and 26 as conservative treatment, but six subjects crossed from the conservative group to the closure group. Three of the six dived in the conservative group before having closure and are classified in both groups depending on whether the dives performed were before or after closure. As a result, there were 42 in the closure group and 23 in the conservative group. Randomisation to the treatment groups was not possible and its absence results in imbalance. Because the closure group is approximately twice as large as the conservative group, similar changes in incidence would have a greater probability of achieving statistical significance in the former. Large shunts were present in more than three-quarters of the closure group but fewer than half of the conservative group. The authors have three definitions of a 'large' PFO, so the definition of large was inconsistent. All ASDs were considered to be large. When dealing with small numbers, one needs patient-level data, but that is lacking and may mask inconsistency in management. The divers were investigated and treated in at least 38 hospitals (some divers did not state where they were treated). We do not know what devices were used for PFO/ASD closure, and closure effectiveness varies, or what tests were performed to assess the effectiveness of closure. The primary end-point was not different between the two groups because only two episodes of confirmed DCI occurred in each group. The authors also considered a softer and subjective end-point, possible DCI. Crucially we are not told what the divers in the conservative group were told constitutes a conservative dive and whether it was consistent. Nor are we told whether they followed the advice given. That is important because it appears that incidence of possible DCI increased considerably in only the conservative group, which means either that the advice they were given on what constitutes a conservative dive was flawed, that the divers failed to follow good advice or that they frequently reported innocent symptoms as possible DCI, because knowledge that they had a PFO may have increased their reporting - introducing further bias. There should be assessment of whether DCI after the intervention was shunt-mediated or had another cause. For that assessment, one needs to know details of the dives resulting in symptoms, clinical manifestations and latency of onset. I have investigated 20 divers who had DCI after PFO closure. In five divers, a contrast echocardiogram showed a significant residual shunt. Typically, the diver had their closure procedure by a cardiologist lacking knowledge of diving medicine and no post-closure contrast echocardiogram was performed. In one case, the diver's PFO was closed but they had a residual pulmonary shunt that was not detected. In those cases where there is a significant residual shunt, the dive profiles, clinical manifestations and latencies of onset were typical of shunt-mediated DCI. Three divers, who had PFO closure with no residual shunt, subsequently had neurological symptoms with manifestations consistent with AGE secondary to pulmonary barotrauma. High resolution CT scans of their chests showed pulmonary bullae and emphysema. The remaining divers seen had no residual shunt but had performed highly provocative dives, usually much deeper than 50 metres' sea water (msw). The most recent case that I saw had dived to 102 metres' fresh water (mfw) in a lake at high altitude breathing trimix. In contrast, several hundred divers in whom I diagnosed a PFO and who elected to dive conservatively had not reported further DCI. I advised them that I have never seen shunt-mediated DCI after dives breathing air to depths of 15 msw or less provided no rules were broken. So I set that as the depth limit or allow them to dive to greater depths breathing nitrox so that there are equivalent partial pressures of nitrogen (e.g., 19 msw with nitrox 32 or 23 msw with nitrox 40) provided they use an air decompression table/algorithm. Alternatively, one can dive using the DCIEM recreational air diving table. Recurrence of DCI after PFO closure may be the result of a residual shunt or may have other causes. It is difficult to draw conclusions about the safety of 'conservative' diving unless one knows what the divers were advised constitutes conservative dives and whether they adhered to the advice.
Topics: Decompression; Decompression Sickness; Diving; Foramen Ovale; Foramen Ovale, Patent; Humans
PubMed: 31177512
DOI: 10.28920/dhm49.2.77-78 -
JAMA Ophthalmology Sep 2021A review of the injury patterns, treatment strategies, and responding physicians' experience during the Port of Beirut blast may help guide future ophthalmic disaster... (Review)
Review
IMPORTANCE
A review of the injury patterns, treatment strategies, and responding physicians' experience during the Port of Beirut blast may help guide future ophthalmic disaster response plans.
OBJECTIVE
To present the ophthalmic injuries and difficulties encountered as a result of the Port of Beirut blast on August 4, 2020.
DESIGN, SETTING, AND PARTICIPANTS
A retrospective medical record review of all patients who presented to the emergency department and 13 ophthalmology outpatient clinics at the American University of Beirut Medical Center for treatment of ophthalmic injuries sustained from the explosion in Port of Beirut, Beirut, Lebanon, from August 4 to the end of November 2020. Patients were identified from emergency records, outpatient records, and operative reports.
MAIN OUTCOMES AND MEASURES
Types of ocular injuries, final best-corrected visual acuity, and need for surgical intervention were evaluated. Visual acuity was measured with correction based on noncycloplegic refraction using the Snellen medical record.
EXPOSURES
Ocular or ocular adnexal injuries sustained from the Port of Beirut explosion.
RESULTS
A total of 39 blast survivors with ocular injuries were included in this study. Twenty-two patients presented with ocular injuries on the day of the blast, and 17 patients presented within the following 3 months to the ophthalmology clinics for a total of 48 eyes of 39 patients were treated secondary to the blast. Thirty-five patients (89.6%) were adults, and 24 (61.5%) were female. A total of 21 patients (53.8%) required surgical intervention, more than half of which were urgently requested on the same day of presentation (14 [35.9%]). Most eye injuries were caused by debris and shrapnel from shattered glass leading to surface injury (26 [54.2%]), eyelid lacerations (20 [41.6%]), orbital fractures (14 [29.2%]), brow lacerations (10 [20.8%]), hyphema (9 [18.8%]), open globe injuries (10 [20.8%]), and other global injuries. Only 7 injured eyes (14.5%) had a final best-corrected visual acuity of less than 20/200, including all 4 open globe injuries with primary no light perception (8.3%) requiring enucleation or evisceration.
CONCLUSIONS AND RELEVANCE
In the aftermath of the Port of Beirut explosion, a review of the ophthalmic injuries showed a predominance of shrapnel-based injuries, many of which had a delayed presentation owing to the strain placed on health care services. Reverting to basic approaches was necessary in the context of a malfunctioning electronic medical record system.
Topics: Adult; Blast Injuries; Explosions; Eye Injuries; Eyelids; Female; Humans; Lacerations; Male; Retrospective Studies
PubMed: 34351374
DOI: 10.1001/jamaophthalmol.2021.2742 -
PloS One 2023Doppler ultrasound (DU) measurements are used to detect and evaluate venous gas emboli (VGE) formed after decompression. Automated methodologies for assessing VGE...
Doppler ultrasound (DU) measurements are used to detect and evaluate venous gas emboli (VGE) formed after decompression. Automated methodologies for assessing VGE presence using signal processing have been developed on varying real-world datasets of limited size and without ground truth values preventing objective evaluation. We develop and report a method to generate synthetic post-dive data using DU signals collected in both precordium and subclavian vein with varying degrees of bubbling matching field-standard grading metrics. This method is adaptable, modifiable, and reproducible, allowing for researchers to tune the produced dataset for their desired purpose. We provide the baseline Doppler recordings and code required to generate synthetic data for researchers to reproduce our work and improve upon it. We also provide a set of pre-made synthetic post-dive DU data spanning six scenarios representing the Spencer and Kisman-Masurel (KM) grading scales as well as precordial and subclavian DU recordings. By providing a method for synthetic post-dive DU data generation, we aim to improve and accelerate the development of signal processing techniques for VGE analysis in Doppler ultrasound.
Topics: Humans; Decompression Sickness; Diving; Embolism, Air; Ultrasonography, Doppler; Subclavian Vein
PubMed: 37104279
DOI: 10.1371/journal.pone.0284922 -
The Journal of Headache and Pain Aug 2017Headache attributed to airplane travel, also named "airplane headache" (AH) is a headache that occurs during take-off and landing. Today, there are still uncertainties... (Review)
Review
BACKGROUND
Headache attributed to airplane travel, also named "airplane headache" (AH) is a headache that occurs during take-off and landing. Today, there are still uncertainties about the pathophysiology and treatment of AH. This systematic review was performed to facilitate identification of the existing literature on AH in order to discuss the current evidence and areas that remain to be investigated in AH.
METHODS
The systematic literature search was performed in 3 relevant medical databases; PubMed, Scopus, and Embase. The search yielded 220 papers and the papers were sorted based on inclusion and exclusion criteria established for this study.
RESULTS
This systematic review included 39 papers. Main findings revealed that AH attacks are clinically stereotyped and appear mostly during landing phases. The headache presents as a severe painful headache that often disappears within 30 min. The pain is unilateral and localized in the fronto-orbital region. Sinus barotrauma has been considered as the main cause of AH. Nonsteroidal anti-inflammatory drugs and triptans have been taken by passengers with AH, to relieve the headache.
CONCLUSIONS
Based on this systematic review, further studies seem required to investigate underlying mechanisms in AH and also to investigate the biological effects of nonsteroidal anti-inflammatory drugs and triptans for alleviating of AH. These studies would advance our understanding of AH pathogenesis and potential use of treatments that are not yet established.
Topics: Aircraft; Anti-Inflammatory Agents, Non-Steroidal; Barotrauma; Frontal Sinus; Headache; Humans; Travel; Tryptamines
PubMed: 28815436
DOI: 10.1186/s10194-017-0788-0 -
Journal of Applied Physiology... Aug 2021Inert gas bubbles are widely accepted as the causative factor of decompression sickness (DCS), resulting in gas embolism and systemic inflammatory responses. The...
Inert gas bubbles are widely accepted as the causative factor of decompression sickness (DCS), resulting in gas embolism and systemic inflammatory responses. The anticonvulsive ketone ester 1,3-butanediol acetoacetate diester (BD-AcAc) was reported to have the characteristics of increasing blood oxygen partial pressure (ppO) and anti-inflammation and was thought to have the potential to reduce bubble formation and alleviate the pathological process of DCS. This study aims to investigate the potential protection of BD-AcAc against DCS in a rat model. A single dose of BD-AcAc was administered orally to adult male rats (5 g/kg body wt), followed by pharmacokinetic analysis or simulated air dives. After decompression, signs of DCS were monitored, and blood was sampled for biochemical measurements. Blood ketosis peaked at 2 h and lasted for more than 4 h. The incidence of DCS was decreased and postponed significantly in rats treated with BD-AcAc compared with those treated with saline ( < 0.05). Although BD-AcAc failed to reduce bubble load ( > 0.05), it showed an obvious decreasing trend. BD-AcAc significantly increased blood ppO and ameliorated oxidative and inflammatory responses, represented by increased plasma malondialdehyde (MDA), IL-1, IL-6, and TNF-α and decreased glutathione thiol ( < 0.05) levels, whereas blood pH remained unchanged ( > 0.05). These results suggest that BD-AcAc exerted beneficial effects on DCS rats mainly related to increasing ppO and anti-inflammatory and antioxidant properties. Together with its capacity for delaying central nervous system (CNS) oxygen toxicity seizures, BD-AcAc might be an ideal drug candidate for DCS prevention and treatment. This is the first study exploring the effects of BD-AcAc on DCS prevention, and it was proven to be an efficient and simple method. The role of BD-AcAc in increasing ppO, anti-inflammatory and antioxidant properties was thought to be the critical mechanism in DCS prevention.
Topics: Acetoacetates; Animals; Butylene Glycols; Decompression; Decompression Sickness; Diving; Male; Rats; Seizures
PubMed: 34166120
DOI: 10.1152/japplphysiol.00035.2021 -
PloS One 2017Decompression sickness (DCS), which is caused by inert gas bubbles in tissues, is an injury of concern for scuba divers, compressed air workers, astronauts, and...
Decompression sickness (DCS), which is caused by inert gas bubbles in tissues, is an injury of concern for scuba divers, compressed air workers, astronauts, and aviators. Case reports for 3322 air and N2-O2 dives, resulting in 190 DCS events, were retrospectively analyzed and the outcomes were scored as (1) serious neurological, (2) cardiopulmonary, (3) mild neurological, (4) pain, (5) lymphatic or skin, and (6) constitutional or nonspecific manifestations. Following standard U.S. Navy medical definitions, the data were grouped into mild-Type I (manifestations 4-6)-and serious-Type II (manifestations 1-3). Additionally, we considered an alternative grouping of mild-Type A (manifestations 3-6)-and serious-Type B (manifestations 1 and 2). The current U.S. Navy guidance allows for a 2% probability of mild DCS and a 0.1% probability of serious DCS. We developed a hierarchical trinomial (3-state) probabilistic DCS model that simultaneously predicts the probability of mild and serious DCS given a dive exposure. Both the Type I/II and Type A/B discriminations of mild and serious DCS resulted in a highly significant (p << 0.01) improvement in trinomial model fit over the binomial (2-state) model. With the Type I/II definition, we found that the predicted probability of 'mild' DCS resulted in a longer allowable bottom time for the same 2% limit. However, for the 0.1% serious DCS limit, we found a vastly decreased allowable bottom dive time for all dive depths. If the Type A/B scoring was assigned to outcome severity, the no decompression limits (NDL) for air dives were still controlled by the acceptable serious DCS risk limit rather than the acceptable mild DCS risk limit. However, in this case, longer NDL limits were allowed than with the Type I/II scoring. The trinomial model mild and serious probabilities agree reasonably well with the current air NDL only with the Type A/B scoring and when 0.2% risk of serious DCS is allowed.
Topics: Decompression Sickness; Humans; Models, Theoretical; Probability
PubMed: 28296928
DOI: 10.1371/journal.pone.0172665