Diving with pre-existing medical conditions

Continuous Glucose Monitoring and Recreational Scuba Diving in Type 1 Diabetes: Head-to-Head Comparison Between Free Style Libre 3 and Dexcom G7 Performance

Background: Scuba diving was previously excluded because of hypoglycemic risks for patients with type 1 diabetes mellitus(T1DM). Specific eligibility criteria and a safety protocol have been defined, whereas continuous glucose monitoring (CGM) systems have enhanced diabetes management. This study aims to assess the feasibility and accuracy of CGM Dexcom G7 and Free Style Libre 3 in a setting of repetitive scuba diving in T1DM, exploring the possibility of nonadjunctive use. Material and Methods: The study was conducted during an event of Diabete Sommerso® association in 2023. Participants followed a safety protocol, with capillary glucose as reference standard (Beurer GL50Evo). Sensors' accuracy was evaluated through median and mean absolute relative difference (MeARD, MARD) and surveillance error grid (SEG). Data distribution and correlation were estimated by Spearman test and Bland-Altman plots. The ability of sensors to identify hypoglycemia was assessed by contingency tables. Results: Data from 202 dives of 13 patients were collected. The overall MARD was 31% (Dexcom G7) and 14.2% (Free Style Libre 3) and MeARD was 19.7% and 11.6%, respectively. Free Style Libre 3 exhibited better accuracy in normoglycemic and hyperglycemic ranges. SEG analysis showed 82.1% (Dexcom G7) and 97.4% (Free Style Libre 3) data on no-risk zone. Free Style Libre 3 better performed on hypoglycemia identification (diagnostic odds ratio of 254.10 vs. 58.95). Neither of the sensors reached the MARD for nonadjunctive use. Conclusions: The study reveals Free Style Libre 3 superior accuracy compared with Dexcom G7 in a setting of repetitive scuba diving in T1DM, except for hypoglycemic range. Both sensors fail to achieve accuracy for nonadjunctive use. Capillary tests remain crucial for safe dive planning, and sensor data should be interpreted cautiously. We suggest exploring additional factors potentially influencing sensor performance.

Cardiovascular considerations on recreational scuba diving. SEC-Clinical Cardiology Association/SEC-Working Group on Sports Cardiology consensus document

The practice of recreational scuba diving has increased worldwide, with millions of people taking part each year. The aquatic environment is a hostile setting that requires human physiology to adapt by undergoing a series of changes that stress the body. Therefore, physical fitness and control of cardiovascular risk factors are essential for practicing this sport. Medical assessment is not mandatory before participating in this sport and is only required when recommended by a health questionnaire designed for this purpose. However, due to the significance of cardiovascular disease, cardiology consultations are becoming more frequent. The aim of the present consensus document is to describe the cardiovascular physiological changes that occur during diving, focusing on related cardiovascular diseases, their management, and follow-up recommendations. The assessment and follow-up of individuals who practice diving with previous cardiovascular disease are also discussed. This document, endorsed by the Clinical Cardiology Association of the Spanish Society of Cardiology (SEC) and the SEC Working Group on Sports Cardiology of the Association of Preventive Cardiology, aims to assist both cardiologists in evaluating patients, as well as other specialists responsible for assessing individuals' fitness for diving practice.

A deep dive into hyperbaric environments and intraocular pressure-a systematic review

Purpose

SCUBA diving exposes participants to a unique hyperbaric environment, but few studies have examined the effects of such an environment on intraocular pressure (IOP) and glaucoma. This systematic review aims to consolidate recent literature findings regarding the impact of increased atmospheric pressure on IOP and glaucoma.

Methods

Three online databases were searched to identify publications encompassing the subjects of diving or increased atmospheric pressure in conjunction with IOP or glaucoma. Three reviewers independently screened the publications and identified eligible articles. Relevant data was extracted from each article. The heterogeneity of the data precluded the conduct of a meta-analysis.

Results

Nine studies met the inclusion criteria. Six experimental studies employed hyperbaric chambers to measure IOP under simulated diving conditions. Among these, IOP exhibited a reduction with increased atmospheric pressures in four studies, while the findings of two studies were inconclusive. One study measured IOP pre- and post-dive and another measured IOP with and without a diving mask. Post-dive, a decrease in IOP was observed, and a statistically significant reduction was noted when subjects wore a diving mask. A retrospective study examining the incidence of acute angle closure glaucoma attack found no association with weather or atmospheric pressure.

Conclusion

The majority of studies found IOP to decrease with increased atmospheric pressure and after diving. The mechanisms underlying this reduction remain incompletely understood, with potential contributors including changes in ocular blood flow, sympathetic responses, and increased oxygenation. Hyperbaric chambers may have potential in future glaucoma treatments, but more studies are required to draw reliable conclusions regarding the safety of diving for glaucoma patients.

SPLF/SMFU/SRLF/SFAR/SFCTCV Guidelines for the management of patients with primary spontaneous pneumothorax

INTRODUCTION

Primary spontaneous pneumothorax (PSP) is the presence of air in the pleural space, occurring in the absence of trauma and known lung disease. Standardized expert guidelines on PSP are needed due to the variety of diagnostic methods, therapeutic strategies and medical and surgical disciplines involved in its management.

METHODS

Literature review, analysis of the literature according to the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) methodology; proposals for guidelines rated by experts, patients and organizers to reach a consensus. Only expert opinions with strong agreement were selected.

RESULTS

A large PSP is defined as presence of a visible rim along the entire axillary line between the lung margin and the chest wall and ≥ 2 cm at the hilum level on frontal chest X-ray. The therapeutic strategy depends on the clinical presentation: emergency needle aspiration for tension PSP; in the absence of signs of severity: conservative management (small PSP), needle aspiration or chest tube drainage (large PSP). Outpatient treatment is possible if a dedicated outpatient care system is previously organized. Indications, surgical procedures and perioperative analgesia are detailed. Associated measures, including smoking cessation, are described.

CONCLUSION

These guidelines are a step towards PSP treatment and follow-up strategy optimization in France.

SPLF/SMFU/SRLF/SFAR/SFCTCV Guidelines for the management of patients with primary spontaneous pneumothorax: Endorsed by the French Speaking Society of Respiratory Diseases (SPLF), the French Society of Emergency Medicine (SFMU), the French Intensive Care Society (SRLF), the French Society of Anesthesia & Intensive Care Medicine (SFAR) and the French Society of Thoracic and Cardiovascular Surgery (SFCTCV)

INTRODUCTION

Primary spontaneous pneumothorax (PSP) is the presence of air in the pleural space, occurring in the absence of trauma and known lung disease. Standardized expert guidelines on PSP are needed due to the variety of diagnostic methods, therapeutic strategies and medical and surgical disciplines involved in its management.

METHODS

Literature review, analysis of literature according to the GRADE (Grading of Recommendation Assessment, Development and Evaluation) methodology; proposals for guidelines rated by experts, patients, and organizers to reach a consensus. Only expert opinions with strong agreement were selected.

RESULTS

A large PSP is defined as presence of a visible rim along the entire axillary line between the lung margin and the chest wall and ≥2 cm at the hilum level on frontal chest x-ray. The therapeutic strategy depends on the clinical presentation: emergency needle aspiration for tension PSP; in the absence of signs of severity: conservative management (small PSP), needle aspiration or chest tube drainage (large PSP). Outpatient treatment is possible if a dedicated outpatient care system is previously organized. Indications, surgical procedures and perioperative analgesia are detailed. Associated measures, including smoking cessation, are described.

CONCLUSION

These guidelines are a step towards PSP treatment and follow-up strategy optimization in France.

Recommandations formalisées d’experts pour la prise en charge des pneumothorax spontanés primaires

Introduction : Le pneumothorax spontané primaire (PSP) est un épanchement gazeux dans la cavité pleurale, survenant hors traumatisme et pathologie respiratoire connue. Des recommandations formalisées d'experts sur le sujet sont justifiées par les pluralités de moyens diagnostiques, stratégies thérapeutiques et disciplines médicochirurgicales intervenant dans leur prise en charge.

Méthodes : Revue bibliographique, analyse de la littérature selon méthodologie GRADE (Grading of Recommendation Assessment, Development and Evaluation) ; propositions de recommandations cotées par experts, patients et organisateurs pour obtenir un consensus. Seuls les avis d'experts avec accord fort ont été retenus.

Résultats : Un décollement sur toute la hauteur de la ligne axillaire et supérieur ou égal à 2 cm au niveau du hile à la radiographie thoracique de face définit la grande abondance. La stratégie thérapeutique dépend de la présentation clinique : exsufflation en urgence pour PSP suffocant ; en l'absence de signe de gravité : prise en charge conservatrice (faible abondance), exsufflation ou drainage (grande abondance). Le traitement ambulatoire est possible si organisation en amont de la filière. Les indications, procédures chirurgicales et l'analgésie périopératoire sont détaillées. Les mesures associées, notamment le sevrage tabagique, sont décrites.

Conclusion : Ces recommandations sont une étape de l'optimisation des stratégies de traitement et de suivi des PSP en France.

A survey on the health status of Dutch scuba diving instructors

INTRODUCTION

As the diving population is ageing, so are the diving instructors. Health issues and the use of prescribed medications are more common when ageing. The death of two diving instructors during one weekend in 2017 in the Netherlands, most likely due to cardiovascular disease, motivated investigation of the prevalence of relevant comorbidities in Dutch diving instructors.

METHODS

All Dutch Underwater Federation diving instructors were invited to complete an online questionnaire. Questions addressed diving experience and current and past medical history including the use of medications.

RESULTS

A response rate of 27% yielded 497 questionnaires (87% male, average age 57.3 years [SD 8.5]). Older instructors were over-represented among responders (82% of males and 75% of females > 50 years versus 66% of males and 51% of females among the invited cohort). Forty-six percent of respondents reported no current medical condition. Hypertension was the most commonly reported condition followed by hay fever and problems equalising ears and sinuses. Thirty-two percent reported no past medical condition. Problems of equalising ears and sinuses was the most common past medical condition, followed by hypertension, joint problems or surgery, and hay fever. Fifty-nine percent used non-prescription medication; predominantly analgesics and nose or ear drops. Forty-nine percent used prescription medicine, mostly cardiovascular and respiratory drugs. Body mass index (BMI) was > 25 kg·m^-2 in 66% of males and 38% of females. All instructors with any type of cardiovascular disease were overweight.

CONCLUSIONS

Nineteen percent of responding diving instructors suffered from cardiovascular disease with above-normal BMI and almost 60% used prescribed or non-prescribed medication. Some dived while suffering from medical issues or taking medications, which could lead to medical problems during emergency situations with their students.

Medical conditions in scuba diving fatality victims in Australia, 2001 to 2013

INTRODUCTION

This study identified pre-existing medical conditions among scuba diving fatalities in Australia from 2001 to 2013, inclusive, and assessed whether these conditions likely contributed to the deaths.

METHODS

The National Coronial Information System (NCIS) was searched for scuba diving-related cases during 2001-2013, inclusive. Coronial findings, witness and police reports, medical histories, and autopsy and toxicology reports were scrutinised for pre-existing medical conditions and autopsy findings. Predisposing factors, triggers, disabling agents, disabling injuries and causes of death were analysed using a validated template.

RESULTS

There were 126 scuba diving-related fatalities identified during the study period. Forty-six (37%) divers were identified as having a significant medical condition which may have contributed to their incident. The most common condition was ischaemic heart disease (IHD) which had been diagnosed in 15 of the divers. Thirty-two (25%) deaths were attributed to cardiac disabling injuries (DI) such as ischaemic heart disease and arrhythmias, although a cardiac DI was thought likely in another six. Respiratory conditions were implicated in eight (6%) deaths, at least four associated with cerebral arterial gas embolism. At least 14 (11%) divers who had contributory pre-existing medical conditions had been cleared to dive by a medical practitioner within the year prior.

CONCLUSIONS

Chronic health-related factors played a major role in almost half of these deaths; primarily cardiac conditions such as IHD and cardiac arrhythmias. Although fitness-to-dive (FTD) assessments have limitations, the high incidence of cardiac-related deaths indicates a need for 'older' divers to be medically assessed for FTD.

Diving after SARS-CoV-2 (COVID-19) infection: Fitness to dive assessment and medical guidance

Scuba diving is a critical activity for commercial industry, military activities, research, and public safety, as well as a passion for many recreational divers. Physicians are expected to provide return-to-diving recommendations after SARS-CoV-2 (COVID-19) infection based upon the best available evidence, often drawn from experience with other, similar diseases. Scuba diving presents unique physiologic challenges to the body secondary to immersion, increased pressure and increased work of breathing. The long-term sequelae of COVID-19 are still unknown, but if they are proven to be similar to other coronaviruses (such as Middle East respiratory syndrome or SARS-CoV-1) they may result in long-term pulmonary and cardiac sequelae that impact divers' ability to safely return to scuba diving. This review considers available literature and the pathophysiology of COVID-19 as it relates to diving fitness, including current recommendations for similar illnesses, and proposes guidelines for evaluation of divers after COVID-19. The guidelines are based upon best available evidence about COVID-19, as well as past experience with determination of diving fitness. It is likely that all divers who have contracted COVID-19 will require a medical evaluation prior to return to diving with emphasis upon pulmonary and cardiac function as well as exercise capacity.

The Occurrence of Arrhythmias and Heart Rate Variability During Diving in Recreational Divers Using Continuous Electrocardiographic Holter Monitoring

The aim of the research was to evaluate the occurrence of arrhythmias and heart rate variability during diving in recreational divers. Continuous electrocardiographic (ECG) Holter monitoring was conducted in a group of 50 divers (age 36,8 ± 8,7). The recorded data included the duration of the dive, including a period of 60 minutes before the dive and 60 minutes after the dive. Moreover, divers filled in a questionnaire that had been prepared for the purpose of the study and the psychological tests State-Trait Anxiety Inventory (STAI). The ECG recordings were synchronised with dive computers to correlate the ECG changes with diving events and analysed for the heart rate, arrhythmias and conduction disorders. The average heart rate was the highest (M=107.34 beats/minute) before diving, and the lowest after diving (M = 102.00 beats/minute). Supraventricular arrhythmias were recorded in nineteen (38%) of the participants of the study. The number of arrhythmias during diving (M = 14,45) is significantly higher than before (M = 9,93, p < 0,01) and after dive (M = 6,02, p < 0,05). All results were obtained from the continuous ECG Holter monitoring. It seems that using continuous ECG monitoring in conditions similar to diving (physical and psychological stress), brings more benefits than traditional, resting electrocardiogram.

Dive Medicine: Current Perspectives and Future Directions

As SCUBA diving continues to rapidly grow in the United States and worldwide, physicians should have a fundamental working knowledge to provide care for an injured diver. SCUBA divers are faced with many hazards at depths that are normally well compensated for at sea level. Pressure gradients, changes in the partial pressure of inhaled gases and gas solubility can have disastrous effects to the diver if not managed properly. Many safety measures in SCUBA diving are governed by the laws of physics, but some have come under scrutiny. This has prompted increased research concerning in water recompression and flying after diving. This article will give physicians an understanding of the dangers divers encounter and the current treatment recommendations. We will also explore some controversies in diving medicine.

Into the deep blue sea: A review of the safety of recreational diving in people with diabetes mellitus

People with diabetes, particularly those being insulin treated, have been for many years considered ineligible for diving, because of the high risk of adverse events. Blood glucose levels tend to decline during diving, probably because of changes in insulin requirements and resistance, due to increased physical activity and effects of hyperbaric environment on glucose tolerance. Strict adherence to safety protocols, in conjunction with optimal physical status, lack of diabetic complications (especially impaired awareness of hypoglycaemia) and satisfactory baseline glycaemic control, seem to minimise the risk of complications during diving. The integration of modern technology into diabetes management, providing potential for underwater continuous glucose monitoring, can be useful in optimising metabolic control before, during and after diving. Despite the significant progress been made on safety issues, there is still a need to implement the relevant recommendations into divers' everyday practice. Existing evidence is mainly derived from small studies and there is a wide heterogeneity in terms of study designs and explored outcomes, rendering the extraction of definitive conclusions challenging. The aim of this review is to present and critically evaluate available evidence, use of technology, and gaps in existing knowledge that deserve further evaluation by future studies.

Challenges in profiling Australian scuba divers through surveys

INTRODUCTION

This study aimed to compare the results from three Australian scuba diver surveys. As the surveys differed in recruitment methods, the expectation was that respondents would differ in some important characteristics.

METHODOLOGY

Anonymous, online, cross-sectional surveys of the demographics, health, diving practices and outcomes were distributed to: (1) Divers Alert Network Asia-Pacific (DAN AP) members; (2) Professional Association of Diving Instructors (PADI) Asia-Pacific members; and (3) divers who had received any PADI non-leadership certification within the previous four years. Only data from divers resident in Australia were analysed.

RESULTS

A total of 2,275 responses were received from current Australian residents, comprising 1,119 of 4,235 (26.4%) DAN members; 350 of 2,600 (13.5%) PADI members; and 806 of 37,000 (2.2%) PADI divers. DAN and PADI members had similar diving careers (medians 14 and 15 years, respectively). PADI members had undertaken more dives (median 800) than DAN members (330) and PADI divers (28). A total of 692 respondents reported suffering from diabetes or a cardiovascular, respiratory, neurological or psychological condition and included 34% of the DAN members and 28% of each of the PADI cohorts. Eighty-four divers had been treated for decompression illness (approximately 5% of DAN and PADI member groups and 1% of the PADI divers). Eighty-seven of 1,156 (7.5%) PADI respondents reported a perceived life-threatening incident while diving.

CONCLUSIONS

Despite low response rates, this study indicates clear differences in the characteristics of the divers in the three cohorts. Therefore, a survey of a single cohort may represent that diving population alone and the findings may be misleading. This bias needs to be clearly understood and any survey findings interpreted accordingly.