Thijs Wingelaar

Royal Netherlands Navy · Diving and Submarine Medical Center

Introduction Pulmonary barotrauma (PBT) with subsequent arterial gas embolism (AGE) is a rare but serious complication during ascent training. In order to prevent alveolar rupture, divers are instructed to exhale during ascents to compensate for the volume expansion of air. Methods The Royal Netherlands Navy Diving School trains ascents in a cont...

In Special Operations Forces (SOF) closed-circuit rebreathers with 100% oxygen are commonly utilized for covert diving operations. Exposure to high partial pressures of oxygen (PO2) could cause damage to the central nervous system (CNS) and pulmonary system. Longer exposure time and higher PO2 leads to faster development of more serious pathology....

Introduction: Routine dipstick urinalysis is part of many dive medical assessment protocols. However, this has a significant chance of producing false-positive or false-negative results in asymptomatic and healthy individuals. Studies evaluating the value of urinalysis in dive medical assessments are limited. Methods: All results from urinalysis as...

INTRODUCTION: Modafinil is used as a countermeasure to limit the effects of fatigue in military aviation. However, literature is conflicting about its negative effects on subsequent sleep. METHODS: This randomized placebo-controlled trial conducted by the Center of Man in Aviation of the Royal Netherlands Airforce is part of a larger study. It incl...

Volatile organic compounds (VOCs) might be associated with pulmonary oxygen toxicity (POT). This pilot study aims to identify VOCs linked to oxidative stress employing an in vitro model of alveolar basal epithelial cells exposed to hyperbaric and hyperoxic conditions. In addition, the feasibility of this in vitro model for POT biomarker research wa...

Introduction: Diving injuries are influenced by a multitude of factors. Literature analysing the full chain of events in diving accidents influencing the occurrence of diving injuries is limited. A previously published ‘chain of events analysis’ (CEA) framework consists of five steps that may sequentially lead to a diving fatality. This study appli...

Introduction: Intrapulmonary air-filled cavities, e.g., bullae, blebs, and cysts, are believed to contribute topulmonary barotrauma (PBT) and arterial gas embolism (AGE) in divers. However, literature is unclear about the prevalence of bullae in healthy adults, ranging from 2.3—33.8%. While this could in part be explained due to increasing quality...

Introduction: Literature suggests pilots experience fatigue differently. So-called fatigue-resistant or -vulnerable individuals might also respond differently to countermeasures or stimulants. This study, which is part of a larger randomized controlled clinical trial, aims to investigate the effect of caffeine and modafinil on fatigue-resistant and...

Pulmonary oxygen toxicity (POT), an adverse reaction to an elevated partial pressure of oxygen in the lungs, can develop as a result of prolonged hyperbaric hyperoxic conditions. Initially starting with tracheal discomfort, it results in pulmonary symptoms and ultimately lung fibrosis. Previous studies identified several volatile organic compounds...

Introduction Nerve agents have emerged as a global threat since their discovery in the 1930s, posing severe risks due to their inhibition of acetylcholinesterase and the subsequent accumulation of acetylcholine in nerve synapses. Despite the enforcement of the Chemical Weapon Convention to control chemical weapons, including nerve agents, recent ev...

INTRODUCTION: Fatigue is a major contributor to aviation accidents. Sufficient sleep may be difficult to achieve under operational conditions in military aviation. Countermeasures include caffeine, however, studies evaluating its effects often do not represent daily practice with regular caffeine consumption. This study aims to establish the effect...

Introduction: Living aboard submarines has a potential negative effect on health. Although studies have evaluated specific health hazards and short-term outcomes, long-term health effects have not been investigated in this population. Methods: Veteran submariners were contacted through the veterans’ society and administered a World Health Organisat...

This review discusses the safety concerns associated with diving while using psychotropic medication and the limited literature available on the topic. Despite the risks, some divers continue to dive while taking these medications, and their reasons for doing so are unclear. The exact mechanisms of action of these drugs in hyperbaric environments a...

One of the hazards of occupational diving is pulmonary oxygen toxicity, which can lead to reduced lung diffusion capacity and fibrosis. The current gold standard to determine the ‘safe limits’ for oxygen was developed more than 50 years ago and lacks the accuracy required for occupational specialists. These restrictions may be overcome by new diagn...

The COMEX-30 hyperbaric treatment table is used to manage decompression sickness in divers but may result in pulmonary oxygen toxicity (POT). Volatile organic compounds (VOCs) in exhaled breath are early markers of hyperoxic stress that may be linked to POT. The present study assessed whether VOCs following COMEX-30 treatment are early markers of h...

INTRODUCTION: Fatigue has negative effects on flight safety, especially in military aviation, where missions are often performed under challenging conditions. Modafinil is a relatively new pharmaceutical able to counter the symptoms of fatigue, but efficacy has not yet been studied in operational military aviation. This study aims to establish effe...

Submarine escape tower training (SETT) is a generally well tolerated, with 18% of the submarines reporting minor equalization problems. One individual had a vagal collapse post-SETT. Based on this sample of 22 submariners, the mean pre-SETT Teeds-score increased statistically significant from 0.51 (range 0-2) to 1.29 post-SETT (range 0-4), with p=0...

Diving or hyperbaric oxygen therapy with increased partial pressures of oxygen (pO2) can have adverse effects such as central nervous system oxygen toxicity or pulmonary oxygen toxicity (POT). Prevention of POT has been a topic of interest for several decades. One of the most promising techniques to determine early signs of POT is the analysis of v...

Similar to aviation, diving is performed in an environment in which acute incapacitation may lead to a fatal outcome. In aeromedicine, a pilot is considered “unfit to fly” when the cardiovascular event risk exceeds one percent per annum, the so-called 1% rule. In diving no formal limits to cardiovascular risk have been established. Cardiovascular r...

Exposure to hyperoxia can lead to pulmonary oxygen toxicity (POT). Preventing POT is relevant from an occupational perspective for occupational and military divers, and from a medical point of view in patients receiving hyperbaric oxygen therapy. The current safe limits (units of pulmonary toxicity dose [uptd]; and many derived equations) are based...

Introduction: The hyperbaric oxygen treatment table 6 (TT6) is widely used to manage dysbaric illnesses in divers and iatrogenic gas emboli in patients after surgery and other interventional procedures. These treatment tables can have adverse effects, such as pulmonary oxygen toxicity (POT). It is caused by reactive oxygen species’ damaging effect...

Exposure to hyperoxic conditions can induce pulmonary oxygen toxicity (POT). Divers of the Special Operations Forces (SOF) use oxygen rebreather systems during dives, and therefore are frequently exposed to hyperoxic conditions. Few studies have reported on POT in this population. This study reports on long-term pulmonary function tests (PFTs) and...

Introduction: Interpreting pulmonary function test (PFT) results requires a valid reference set and a cut-off differentiating pathological from physiological pulmonary function; the lower limit of normal (LLN). However, in diving medicine it is unclear whether an LLN of 2.5% (LLN-2.5) or 5% (LLN-5) in healthy subjects constitutes an appropriate cu...

Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing performance in-flight (chronic) fatigue has negative long-term health effects. Possible causes of fatigue include sleep loss, extended time awake, circadian phase irregularities and work load. Despite regulations limiting flight time and enabling optima...

Increased hydrostatic pressure as experienced during immersion and submersion has effects on the circulation. The main effect is counteracting of gravity by buoyancy, which results in reduced extravasation of fluid. Immersion in a cold liquid leads to peripheral vasoconstriction, which centralizes the circulation. Additionally, a pressure differenc...

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 comorbi...

Introduction: Intrapulmonary pathology, such as bullae or blebs, can cause pulmonary barotrauma when diving. Many diving courses require chest X-rays (CXR) or high-resolution computed tomography (HRCT) to exclude asymptomatic healthy individuals with these lesions. The ability of routine CXRs and HRCT to assess fitness to dive has never been evalua...

INTRODUCTION: Many regulations for aeromedical assessments state that a ratio between forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of < 0.7 should be evaluated by a pulmonary specialist. The Global Lung Initiative (GLI) reference values introduced the lower limit of normal (LLN 2.5), in which the lowest 2.5% of the...

Introduction: The Netherlands Maritime Special Operations Forces use closed circuit oxygen rebreathers (O₂-CCR), which can cause pulmonary oxygen toxicity (POT). Recent studies demonstrated that volatile organic compounds (VOCs) can be used to detect POT in laboratory conditions. It is unclear if similar VOCs can be identified outside the laborato...

The use of an inspiratory oxygen fraction of 0.80 during surgery is a topic of ongoing debate. Opponents claim that increased oxidative stress, atelectasis, and impaired oxygen delivery due to hyperoxic vasoconstriction are detrimental. Proponents point to the beneficial effects on the incidence of surgical site infections and postoperative nausea...

Introduction: Hearing loss (HL) is common in the adult working population. It is widely assumed that diving is a risk factor for HL. However, studies with sufficient follow-up comparing HL in divers to non-divers are limited. This study aimed to assess the hearing threshold (HT) of Royal Netherlands Navy divers who had been diving for more than 15...

Exposure to oxygen under increased atmospheric pressures can induce pulmonary oxygen toxicity (POT). Exhaled breath analysis using gas chromatography-mass spectrometry (GC-MS) has revealed that volatile organic compounds (VOCs) are associated with inflammation and lipoperoxidation after hyperbaric-hyperoxic exposure. Electronic nose (eNose) technol...

Background: Physiological changes are induced by immersion, swimming and using diving equipment. Divers must be fit to dive. Using medication may impact the capacity to adapt to hyperbaric conditions. The aim of this systematic review is to assess the interaction of diving/hyperbaric conditions and medication and to provide basic heuristics to sup...

Introduction Hyperbaric hyperoxia, both in diving and HBOT, can induce pulmonary oxygen toxicity (POT). Exposure is historically expressed in Units of Pulmonary Toxicity Dose (UPTD), which is based on the decrease in vital capacity (VC), but its validity has been questioned. Other diagnostic modalities, such as diffusion capacity, show differences...

Sportduiken wordt in toenemende mate beoefend. Daarmee wordt de kans groter dat er patiënten op uw spreekuur komen met vragen over de invloed van hun aandoening op het duiken. Duiken vraagt bijzondere aanpassingen van het menselijk lichaam. Ziekte of medicatie kan die aanpassing verstoren of onmogelijk maken, met (blijvend) letsel tot gevolg. Deze...

Intensity of the VOCs, with 95% CI. ∗Significant difference in mean values. Results of the ANOVA are shown in the graph of each VOC.

Introduction Although hyperbaric oxygen therapy (HBOT) has beneficial effects, some patients experience fatigue and pulmonary complaints after several sessions. The current limits of hyperbaric oxygen exposure to prevent pulmonary oxygen toxicity (POT) are based on pulmonary function tests (PFT), but the limitations of PFT are recognized worldwide....

Introduction: Exposure to hyperbaric hyperoxic conditions can lead to pulmonary oxygen toxicity. Although a decrease in vital capacity has long been the gold standard, newer diagnostic modalities may be more accurate. In pulmonary medicine, much research has focussed on volatile organic compounds (VOCs) associated with inflammation in exhaled breat...

INTRODUCTION: Pulmonary function testing (PFT) is an important part of dive medical examinations. Depending on the standard used to assess fitness to dive, different reference sets and fixed cut-off points are used. Reference values are part of an ongoing debate regarding the validity and accuracy related to different age groups, sex and ethnic bac...

Longitudinal monitoring of hearing threshold in Navy Divers has shown that hearing loss in divers is comparible to the regular working population (ISO 7029).

Abstract (Wingelaar TT, van Ooij PJAM, van Hulst RA. Otitis externa in military divers: more frequent and less harmful than reported. Diving and Hyperbaric Medicine. 2017 March;47(1):4-8.) Introduction: Although otitis externa (OE) is a common disease, data related to (military) divers are limited. This study aimed to determine the incidence of OE...

Developing clinical reasoning skills early in medical education is important. However, research to uncover students' educational needs for learning clinical reasoning during clerkships is limited. The aim of our study was to investigate these needs. Focus group discussions with an independent moderator were conducted. Students were included directl...