Bernd E. Winkler

Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation—A randomized cross-over trial ☆

INTRODUCTION Drowning is a common cause of death in young adults. The 2010 guidelines of the European Resuscitation Council call for in-water-resuscitation (IWR). There has been controversy about IWR amongst emergency and diving physicians for decades. The aim of the present study was assessing the efficacy of IWR. METHODS In this randomized cross-over trial, nineteen lifeguards performed a rescue manoeuvre over a 100 m distance in open water. All subjects performed the procedure four times in random order: with no ventilation (NV) and transportation only, mouth-to-mouth ventilation (MMV), bag-mask-ventilation (BMV) and laryngeal tube ventilation (LTV). Tidal volumes, ventilation rate and minute-volumes were recorded using a modified Laerdal Resusci Anne manikin. Furthermore, water aspiration and number of submersions of the test mannequin were assessed, as well as the physical effort of the lifeguard rescuers.One lifeguard subject did not complete MMV due to exhaustion and was excluded from analysis. RESULTS NV was the fastest rescue manoeuvre (advantage ∼40s). MMV and LTV were evaluated as efficient and relatively easy to perform by the lifeguards. While MMV (mean 199 ml) and BMV (mean 481 ml) were associated with a large amount of aspirated water, aspiration was significantly lower in LTV (mean 118 ml). The efficacy of ventilation was consistently good in LTV (Vt=447 ml), continuously poor in BMV (Vt=197) and declined substantially during MMV (Vt=1,019 ml initially and Vt=786 ml at the end). The physical effort of the lifeguards was remarkably higher when performing IWR: 3.7 in NV, 6.7 in MMV, 6.4 in BMV and 4.8 in LTV as measured on the 0-10 visual analogue scale. CONCLUSION IWR in open water is time consuming and physically demanding. The IWR training of lifeguards should put more emphasis on a reduction of aspiration. The use of ventilation adjuncts like the laryngeal tube might ease IWR, reduce aspiration of water and increase the efficacy of ventilation during IWR.

Pulmonary Function in Children After Open Water SCUBA Dives

An increasing number of children and adolescents is diving with Self-Contained Underwater Breathing Apparatus (SCUBA). SCUBA diving is associated with health risks such as pulmonary barotrauma, especially in children and in individuals with airflow limitation. As no data has been published on the effects of open-water diving on pulmonary function in children, the objective of this study was to evaluate the effects of SCUBA dives on airflow in children. 16 healthy children aged 10-13 years underwent spirometry and a cycle-exercise challenge while breathing cold air. They subsequently performed dives to 1-m and 8-m depth in random order. Pulmonary function was measured before and after the exercise challenge and the dives. There were statistically significant decreases in FEV1, FVC, FEV1/FVC, MEF25 and MEF50 after the cold-air exercise challenge and the dives. Changes in lung function following the exercise challenge did not predict the responses to SCUBA diving. In 3 children the post-dive decrements in FEV1 exceeded 10%. These children had a lower body weight and BMI percentile. SCUBA diving in healthy children may be associated with relevant airflow limitation. A low body mass might contribute to diving-associated bronchoconstriction. In the majority of subjects, no clinically relevant airway obstruction could be observed.

Effectiveness and Safety of In-Water Resuscitation Performed by Lifeguards and Laypersons: A Crossover Manikin Study

Abstract Objective. Drowning is associated with a high mortality and morbidity and a common cause of death. In-water resuscitation (IWR) in the case of drowning accidents has been recommended by certain resuscitation guidelines in the last several years. IWR has been discussed controversially in the past, especially with regard to the delay of chest compressions, effectiveness of ventilation, and hazard to the rescuer. The aim of the present study was to assess the effectiveness and safety of IWR. Methods. In this crossover manikin study, 21 lifeguards and 21 laypersons performed two rescue procedures in an indoor swimming pool over a 50-meter distance: In random order, one rescue procedure was performed with in-water ventilation and one without. Tidal and minute volumes were recorded using a modified Laerdal Resusci Anne (Laerdal Medical, Stavanger, Norway) and total rescue duration, submersions, water aspiration by the victim, and physical effort were assessed. Results. IWR resulted in significant increases in rescue duration (lifeguards: 106 vs. 82 seconds; laypersons: 133 vs. 106 seconds) and submersions (lifeguards: 3 vs. 1; laypersons: 5 vs. 0). Furthermore, water aspiration (lifeguards: 112 vs. 29 mL; laypersons: 160 vs. 56 mL) and physical effort (lifeguards: visual analog scale [VAS] score 7 vs. 5; laypersons: VAS score 8 vs. 6) increased significantly when IWR was performed. Lifeguards achieved significantly better ventilation characteristics and performed both rescue procedures faster and with lower side effects. IWR performed by laypersons was insufficient with regard to both tidal and minute volumes. Conclusions. In-water resuscitation is associated with a delay of the rescue procedure and a relevant aspiration of water by the victim. IWR appears to be possible when performed over a short distance by well-trained professionals. The training of lifeguards must place particular emphasis on a reduction of submersions and aspiration when IWR is performed. IWR by laypersons is exhausting, time-consuming, and inefficient and should probably not be recommended. Key words: drowning; near-drowning; hypoxia; ventilation, artificial; respiration, artificial; resuscitation, in-water

N-terminal prohormone of brain natriuretic peptide: a useful tool for the detection of acute pulmonary artery embolism in post-surgical patients

BACKGROUND Acute pulmonary embolism (APE) is an important clinical problem in patients after major surgery and often remains a difficult diagnosis because of unspecific clinical symptoms. Therefore, we investigated the role of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) for the detection of APE. METHODS In 44 patients with suspected APE referred to the intensive care unit after major surgery, serum NT-proBNP, troponin-I, and D-dimers were measured according to the standard hospital protocol. To definitively confirm or exclude APE, all patients underwent an angiographic CT scan of the thorax. RESULTS APE was confirmed in 28 and excluded in 16 patients by CT scan. NT-proBNP was significantly (P<0.01) higher in patients with APE [4425 (sd 8826; range 63-35 000) pg ml(-1)] compared with those without [283 (sd 327; range 13-1133) pg ml(-1)]. The sensitivity of the NT-proBNP screening was 93%, specificity 63%, positive predictive value 81%, and negative predictive value 83%. There were no significant (P = 0.96) differences in D-dimers between subjects with and without APE [confirmed APE: 511 (sd 207; range 83-750) μg litre(-1); excluded APE: 509 (sd 170; range 230-750) μg litre(-1)]. Troponin-I levels were not elevated in 32% of the patients with APE. CONCLUSIONS D-dimer levels are frequently elevated in post-surgical patients and not applicable for confirmation or exclusion of APE. In contrast, NT-proBNP appears to be a useful biomarker for APE diagnosis in the postoperative setting. In the case of NT-proBNP levels below the upper reference limit, haemodynamically relevant APE is unlikely. Troponin-I in contrast is not considered to be helpful.

Effects of a media campaign on resuscitation performance of bystanders: a manikin study

Objective Cardiac arrest is associated with a poor outcome if cardiopulmonary resuscitation (CPR) is delayed. Nevertheless, CPR performance by laypersons in witnessed cardiac arrest is frequently poor. The present study evaluated the effect of a media campaign on CPR performance. Participants and methods CPR performance of 1000 individuals who did not have any medical background was evaluated using a resuscitation manikin. The media campaign consisted of flyers, posters, and electronic advertisement. Five hundred individuals were evaluated before the media campaign and 500 individuals after the media campaign. Age and male/female ratio were comparable within each of the groups. Premedia campaign performance was compared with postmedia campaign performance with respect to chest compressions and ventilation metrics. Results Chest compression depth and total compression work were significantly higher after the media campaign: median depth 51 mm postcampaign versus 45 mm precampaign (P<0.001), median cumulative compression work postcampaign 4176 versus 2462 mm precampaign (P<0.001). Tidal volumes and ventilation work were significantly lower following the media campaign, but did not differ between participants who had acknowledged exposure to the campaign and those who did not. Ventilation performance was generally poor across the two groups both before and after the media campaign. Conclusion A simple and cost-efficient media campaign appears to enhance the performance of chest compressions. Ventilation performance and the rate of CPR performance were not increased by the campaign.

[Hyperbaric therapy and diving medicine - diving medicine - present state and prospects].

The diving accident (decompression incident, DCI) occurs in the decompression phase of dives. The DCI can either be caused by an arterial gas embolism (AGE) subsequent to a pulmonary barotrauma or by the formation of inert gas bubbles subsequent to a reduction of ambient pressure during the ascent from depth. In contrast to the traditional assumption that decompression incidents only occur if decompression rules are neglected, recent data indicate that a vast amount of diving accidents occur even though divers adhered to the rules. Hence, there is a large inter- and intraindividual variability in the predisposition for diving accidents. Within the past few years, the molecular understanding of the pathophysiology of diving accidents has improved considerably. It is now well accepted that pro-inflammatory and pro-coagulatory mechanisms play a central role. Moreover, microparticles are increasingly discussed in the pathogenesis of diving accidents. These new molecular findings have not yet resulted in new therapeutic approaches. However, new approaches of preconditioning before the dive have been developed which are intended to reduce the risk of diving accidents. The symptoms of a diving accident show a large variability and range. They reach from pruritus over tension in the female breast, marbled skin and pain in the joints to severe neurological disability like paraplegia or hemiplegia. Furthermore, pulmonary symptoms can be a result of a pulmonary gas embolism and/or a tension pneumothorax. Extreme cases can also manifest as generalized, difficult-to-treat seizures, loss of consciousness or even death. The evidence-based therapy of diving accidents consists of an immediate application of 100% inspiratory O2. This can be performed via a demand valve, face mask with reservoir bag or ventilation bag connected to a reservoir bag. Fluid substitution is performed by i. v. infusion of 500-1000ml/h of cristalloids. If consciousness is not impaired, the diver is positioned in a supine position, in case of impaired or absent consciousness in a lateral recovery position. Especially in severe cases of DCI a fast transfer to a qualified hyperbaric center and the earliest possible hyperbaric O2-therapy is essential.

Oxylator and SCUBA dive regulators: useful utilities for in-water resuscitation

Introduction In water resuscitation has been reported to enhance the outcome of drowning victims. Mouth-to-mouth ventilation during swimming is challenging. Therefore, the efficacy of ventilation utilities was evaluated. Methods Ventilation was assessed with the Oxylator ventilator, as well as the consecutive self-contained underwater breathing apparatus (SCUBA) regulators using an anaesthetic test lung: Poseidon Cyklon 5000, Poseidon XStream, Apeks TX 100, Spiro Arctic, Scubapro Air2 and Buddy AutoAir. Results Oxylator, Apeks TX 100, Arctic and Buddy AutoAir delivered reliable peak pressures and tidal volumes. In contrast, the ventilation parameters remarkably depended on duration and depth of pressing the purge button in Poseidon Cyklon 5000, Poseidon XStream and Scubapro Air2. Critical peak pressures occurred during ventilation with all these three regulators. Discussion The use of Poseidon Cyklon 5000, Poseidon XStream and Scubapro Air2 regulators is consequently not recommended for in-water ventilation. With the limitation that the devices were tested with a test lung and not in a human field study, Apeks TX 100, Spiro Arctic and Buddy AutoAir might be used for emergency ventilation and probably ease in-water resuscitation for the dive buddy of the victim. Professional rescue divers could be equipped with the Oxylator and an oxygen tank to achieve an early onset of efficient in-water ventilation in drowning victims.

Mechanical ventilation and resuscitation under water: Exploring one of the last undiscovered environments – A pilot study

INTRODUCTION Airway management, mechanical ventilation and resuscitation can be performed almost everywhere--even in space--but not under water. The present study assessed the technical feasibility of resuscitation under water in a manikin model. METHODS Tracheal intubation was assessed in a hyperbaric chamber filled with water at 20 m of depth using the Pentax AWS S100 video laryngoscope, the Fastrach™ intubating laryngeal mask and the Clarus optical stylet with guidance by a laryngeal mask airway (LMA) and without guidance. A closed suction system was used to remove water from the airways. A test lung was ventilated to a maximum depth of 50 m with a modified Oxylator(®) EMX resuscitator with its expiratory port connected either to a demand valve or a diving regulator. Automated chest compressions were performed to a maximum depth of 50 m using the air-driven LUCAS™ 1. RESULTS The mean cumulative time span for airway management until the activation of the ventilator was 36 s for the Fastrach™, 57 s for the Pentax AWS S100, 53s for the LMA-guided stylet and 43 s for the stylet without LMA guidance. Complete suctioning of the water from the airways was not possible with the suction system used. The Oxylator(®) connected to the demand valve ventilated at 50 m depth with a mean ventilation rate of 6.5 min(-1) vs. 14.7 min(-1) and minute volume of 4.5 l min(-1) vs. 7.6 l min(-1) compared to the surface. The rate of chest compression at 50 m was 228 min(-1) vs. 106 min(-1) compared to surface. The depth of compressions decreased with increasing depth. CONCLUSION Airway management under water appears to be feasible in this manikin model. The suction system requires further modification. Mechanical ventilation at depth is possible but modifications of the Oxylator(®) are required to stabilize ventilation rate and administered minute volumes. The LUCAS™ 1 cannot be recommended at major depth.

Helicopter-based in-water resuscitation with chest compressions: a pilot study

Background Drowning is a relevant worldwide cause of severe disability and death. The delay of ventilations and chest compressions is a crucial problem in drowning victims. Hence, a novel helicopter-based ALS rescue concept with in-water ventilation and chest compressions was evaluated. Methods Cardio pulmonary resuscitation (CPR) and vascular access were performed in a self-inflating Heliboat platform in an indoor wave pool using the Fastrach intubating laryngeal mask, the Oxylator resuscitator, Lund University Cardiopulmonary Assist System (LUCAS) chest compression device and EZ-IO intraosseous power drill. The time requirement and physical exertion on a Visual Analogue Scale (VAS) were compared between a procedure without waves and with moderate swell. Results Measurement of the elapsed time of the various stages of the procedure did not reveal significant differences between calm water and swell: Ventilation was initiated after 02:48 versus 03:02 and chest compression after 04:20 versus 04:18 min; the intraosseous cannulisation was completed after 05:59 versus 06:30 min after a simulated jump off the helicopter. The attachment of the LUCAS to the mannequin and the intraosseous cannulisation was rated significantly more demanding on the VAS during swell conditions. Conclusions CPR appears to be possible when performed in a rescue platform with special equipment. The novel helicopter-based strategy appears to enable the rescuers to initiate CPR in an appropriate length of time and with an acceptable amount of physical exertion for the divers. The time for the helicopter to reach the patient will have to be very short to minimise neurological damage in the drowning victim.

Effects of FLIRT on Bubble Growth in Man

Recompression during decompression has been suggested to possibly reduce the risk of decompression sickness (DCS). The main objective of the current study was to investigate the effects of FLIRT (First Line Intermittent Recompression Technique) on bubble detection in man. 29 divers underwent 2 simulated dives in a dry recompression chamber to a depth of 40 msw (500 kPa ambient pressure) in random order. A Buehlmann-based decompression profile served as control and was compared to an experimental profile with intermittent recompression during decompression (FLIRT). Circulating bubbles in the right ventricular outflow tract (RVOT) were monitored by Doppler ultrasound and quantified using the Spencer scoring algorithm. Heat shock protein 70 (HSP70), thrombocytes, D-Dimers and serum osmolarity were analyzed before and 120 min after the dive. Both dive profiles elicited bubbles in most subjects (range Spencer 0-4). However, no statistically significant difference was found in bubble scores between the control and the experimental dive procedure. There was no significant change in either HSP70, thrombocytes, and D-Dimers. None of the divers had clinical signs or symptoms suggestive of DCS. We conclude that FLIRT did not significantly alter the number of microbubbles and thus may not be considered superior to classical decompression in regards of preventing DCS.