Reliability of continuous vital sign monitoring in post-operative patients employing consumer-grade fitness trackers: A randomised pilot trial.

Introduction: Fitness trackers can provide continuous monitoring of vital signs and thus have the potential to become a complementary, mobile and effective tool for early detection of patient deterioration and post-operative complications. Methods: To evaluate potential implementations in acute care setting, we included 36 patients after moderate to major surgery in a recent randomised pilot trial to compare the performance of vital sign monitoring by three different fitness trackers (Apple Watch 7, Garmin Fenix 6pro and Withings ScanWatch) with established standard clinical monitors in post-anaesthesia care units and monitoring wards. Results: During a cumulative period of 56 days, a total of 53,197 heart rate (HR) measurements, as well as 12,219 measurements of the peripheral blood oxygen saturation (SpO2) and 28,954 respiratory rate (RR) measurements were collected by fitness trackers. Under real-world conditions, HR monitoring was accurate and reliable across all benchmarked devices (r = [0.95;0.98], p < 0.001; Bias = [-0.74 bpm;-0.01 bpm]; MAPE∼2%). However, the performance of SpO2 (r = [0.21;0.68]; p < 0.001; Bias = [-0.46%;-2.29%]; root-mean-square error = [2.82%;4.1%]) monitoring was substantially inferior. RR measurements could not be obtained for two of the devices, therefore exclusively the accuracy of the Garmin tracker could be evaluated (r = 0.28, p < 0.001; Bias = -1.46/min). Moreover, the time resolution of the vital sign measurements highly depends on the tracking device, ranging from 0.7 to 117.94 data points per hour. Conclusion: According to the results of the present study, tracker devices are generally reliable and accurate for HR monitoring, whereas SpO2 and RR measurements should be interpreted carefully, considering the clinical context of the respective patients.

Evaluating blood oxygen saturation measurements by popular fitness trackers in postoperative patients: A prospective clinical trial.

Blood oxygen saturation is an important clinical parameter, especially in postoperative hospitalized patients, monitored in clinical practice by arterial blood gas (ABG) and/or pulse oximetry that both are not suitable for a long-term continuous monitoring of patients during the entire hospital stay, or beyond. Technological advances developed recently for consumer-grade fitness trackers could-at least in theory-help to fill in this gap, but benchmarks on the applicability and accuracy of these technologies in hospitalized patients are currently lacking. We therefore conducted at the postanaesthesia care unit under controlled settings a prospective clinical trial with 201 patients, comparing in total >1,000 oxygen blood saturation measurements by fitness trackers of three brands with the ABG gold standard and with pulse oximetry. Our results suggest that, despite of an overall still tolerable measuring accuracy, comparatively high dropout rates severely limit the possibilities of employing fitness trackers, particularly during the immediate postoperative period of hospitalized patients.

Accuracy and Systematic Biases of Heart Rate Measurements by Consumer-Grade Fitness Trackers in Postoperative Patients: Prospective Clinical Trial.

BACKGROUND: Over the recent years, technological advances of wrist-worn fitness trackers heralded a new era in the continuous monitoring of vital signs. So far, these devices have primarily been used for sports. OBJECTIVE: However, for using these technologies in health care, further validations of the measurement accuracy in hospitalized patients are essential but lacking to date. METHODS: We conducted a prospective validation study with 201 patients after moderate to major surgery in a controlled setting to benchmark the accuracy of heart rate measurements in 4 consumer-grade fitness trackers (Apple Watch 7, Garmin Fenix 6 Pro, Withings ScanWatch, and Fitbit Sense) against the clinical gold standard (electrocardiography). RESULTS: All devices exhibited high correlation (r≥0.95; P<.001) and concordance (rc≥0.94) coefficients, with a relative error as low as mean absolute percentage error <5% based on 1630 valid measurements. We identified confounders significantly biasing the measurement accuracy, although not at clinically relevant levels (mean absolute error<5 beats per minute). CONCLUSIONS: Consumer-grade fitness trackers appear promising in hospitalized patients for monitoring heart rate. TRIAL REGISTRATION: ClinicalTrials.gov NCT05418881; https://www.clinicaltrials.gov/ct2/show/NCT05418881.

Effectiveness of different central venous catheter fixation suture techniques: An in vitro crossover study.

PURPOSE: Proper fixation of central venous catheters (CVCs) is an integral part of safety to avoid dislodgement and malfunction. However, the effectiveness of different CVC securement sutures is unknown. METHODS: Analysis of maximum dislodgement forces for CVCs from three different manufacturers using four different suture techniques in an in vitro tensile loading experiment: 1. "clamp only", 2. "clamp and compression suture", 3. "finger trap" and 4. "complete", i.e., "clamp + compression suture + finger trap". Twenty-five tests were performed for each of the three CVC models and four securement suture techniques (n = 300 test runs). RESULTS: The primary cause of catheter dislodgement was sliding through the clamp in techniques 1 and 2. In contrast, rupture of the suture was the predominant cause for dislodgement in techniques 2 and 3. Median (IQR 25-75%) dislodgement forces were 26.0 (16.6) N in technique 1, 26.5 (18.8) N in technique 2, 76.7 (18.7) N in technique 3, and 84.8 (11.8) N in technique 4. Post-hoc analysis demonstrated significant differences (P < .001) between all pairwise combinations of techniques except technique 1 vs. 2 (P = .98). CONCLUSIONS: "Finger trap" fixation at the segmentation site considerably increases forces required for dislodgement compared to clamp-based approaches.

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.

Passive continuous positive airway pressure ventilation during cardiopulmonary resuscitation: a randomized cross-over manikin simulation study.

While controlled ventilation is most frequently used during cardiopulmonary resuscitation (CPR), the application of continuous positive airway pressure (CPAP) and passive ventilation of the lung synchronously with chest compressions and decompressions might represent a promising alternative approach. One benefit of CPAP during CPR is the reduction of peak airway pressures and therefore a potential enhancement in haemodynamics. We therefore evaluated the tidal volumes and airway pressures achieved during CPAP-CPR. During CPR with the LUCAS™ 2 compression device, a manikin model was passively ventilated at CPAP levels of 5, 10, 20 and 30 hPa with the Boussignac tracheal tube and the ventilators Evita® V500, Medumat® Transport, Oxylator® EMX, Oxylog® 2000, Oxylog® 3000, Primus® and Servo®-i as well as the Wenoll® diver rescue system. Tidal volumes and airway pressures during CPAP-CPR were recorded and analyzed. Tidal volumes during CPAP-CPR were higher than during compression-only CPR without positive airway pressure. The passively generated tidal volumes increased with increasing CPAP levels and were significantly influenced by the ventilators used. During ventilation at 20 hPa CPAP via a tracheal tube, the mean tidal volumes ranged from 125 ml (Medumat®) to 309 ml (Wenoll®) and the peak airway pressures from 23 hPa (Primus®) to 49 hPa (Oxylog® 3000). Transport ventilators generated lower tidal volumes than intensive care ventilators or closed-circuit systems. Peak airway pressures during CPAP-CPR were lower than those during controlled ventilation CPR reported in literature. High peak airway pressures are known to limit the applicability of ventilation via facemask or via supraglottic airway devices and may adversely affect haemodynamics. Hence, the application of ventilators generating high tidal volumes with low peak airway pressures appears desirable during CPAP-CPR. The limited CPAP-CPR capabilities of transport ventilators in our study might be prerequisite for future developments of transport ventilators.

Formulas for prediction of insertion depths of internal jugular vein catheters adjusted to body height categories.

PURPOSE: Whether formulas for prediction of central venous catheter (CVC) insertion depths have different applicability in patients with different body heights is not known. Goal of study was to test formulas for catheterizations of internal jugular veins (IJVs) in a population of different body height classes with correct CVC tip positions. METHODS: Consecutive adult patients requiring CVC for cardiac surgery were enrolled and those with tip positions at the junction of the superior vena cava and the right atrium ±1 cm underwent formula analysis. Precision of formula prediction was calculated for three classes of body height. RESULTS: Of the 635 included patients, 254 underwent right IJV catheterization and 381 underwent left IJV catheterization, respectively. Formula-guided approach for both right [formulas (height/10) (in cm) and (height/10) -1 (in cm)] and left [formula (height/10) + 4 (in cm)] IJV CVC was more precise in patients with a body height of 170-180 cm compared with patients with a body height <170 cm (who required deeper insertion than predicted by formula) and patients with a body height >180 cm (who required a more proximal insertion than predicted by formula). CONCLUSIONS: Independent from body height classes, all formulas calculated a relatively low likelihood of atrial positions but high risks of proximal mal-positioning. Thus, considering inter-individual differences of vascular anatomy and for safety reasons, formulas cannot be recommended.

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.

A novel rescue-tube device for in-water resuscitation.

BACKGROUND: In-water resuscitation (IWR) is recommended in the 2010 guidelines of the European Resuscitation Council. As IWR represents a physical challenge to the rescuer, a novel Rescue Tube device with an integrated "Oxylator" resuscitator might facilitate IWR. The aim of the present study was the assessment of IWR using the novel Rescue Tube device. METHODS: Tidal and minute volumes were recorded using a modified Laerdal Resusci Anne mannequin. Furthermore, rescue time, water aspiration, submersions, and physical exertion were assessed. In this randomized cross-over trial, 17 lifeguards performed four rescue maneuvers over a 100-m distance in open water in random order: no ventilation (NV), mouth-to-mouth ventilation (MMV), Oxylator-aided mask ventilation (OMV), and Oxylator-aided laryngeal tube ventilation (OLTV). RESULTS: OLTV resulted in effective ventilation over the entire rescue distance with the highest mean minute volumes (NV 0, MMV 2.9, OMV 4.1, OLTV 7.6 L · min(-1)). NV was the fastest rescue maneuver while IWR prolonged the rescue maneuver independently of the method of ventilation (mean total rescue time: NV 217, MMV 280, OMV 292, OLTV 290 s). Aspiration of substantial amounts of water occurred only during MMV (mean NV 20, MMV 215, OMV 15, OLTV 6 ml). NV and OLTV were rated as moderately challenging by the lifeguards, whereas MMV and OMV were rated as substantially demanding on a 0-10 visual analog scale (NV 5.3, MMV 7.8, OMV 7.6, OLTV 5.9). DISCUSSION: The device might facilitate IWR by providing effective ventilation with minimal aspiration and by reducing physical effort. Another advantage is the possibility of delivering 100% oxygen.

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.

Lung function after cold-water dives with a standard scuba regulator or full-face-mask during wintertime.

INTRODUCTION: Full-face-masks (FFM) prevent the diver's face from cold and can support nasal breathing underwater. The aim of the study was to evaluate the effect of the use of FFMs on lung function and wellbeing. METHODS: Twenty-one, healthy, non-asthmatic divers performed two cold-water dives (4°C, 25 min, 10 metres' depth) - one with a FFM and the other with a standard scuba regulator (SSR). Spirometry was performed before and after each dive and well-being and cold sensation were assessed after the dives. RESULTS: Significant decreases in forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and midexpiratory flow at 75% of FVC (MEF75) occurred after both FFM and SSR dives. Changes in FVC and FEV1 did not differ significantly between FFM and SSR dives. However, the mid-expiratory flows measured at 50% and 25% of FVC (MEF50 and MEF25) were significantly lower 10 minutes after the FFM dive compared to 10 minutes after the SSR dive. The wellbeing and cold sensation of the divers were significantly improved with FFM dives compared to SSR dives. CONCLUSIONS: Cold-water dives during wintertime can be associated with airway narrowing. During cold-water dives, the use of a FFM appears to reduce the cold sensation and enhance the well-being of the divers. However, a FFM does not appear to prevent airway narrowing in healthy, non-asthmatic subjects.

Rescue of drowning victims and divers: is mechanical ventilation possible underwater? A pilot study.

INTRODUCTION: In-water resuscitation has recently been proposed in the European resuscitation guidelines. Initiation of mechanical ventilation underwater might be considered when an immediate ascent to the surface is impossible or dangerous. The present study evaluated the feasibility of such ventilation underwater. METHODS: A resuscitation manikin was ventilated using an Interspiro® MK II full-face mask or with an Oxylator® ventilator via a facemask or a laryngeal tube, or with mouth-to-tube inflation. Tidal volumes achieved by the individual methods of ventilation were assessed. The ventilation tests were performed during dives in the wet compartment of a recompression chamber and in a lake. Ventilation was tested at 40, 30, 20, 12, 9 and 6 metres' depth. RESULTS: Ventilation was impossible with the cuffed mask and only sufficient after laryngeal intubation for a small number of breaths. Laryngeal tube ventilation was associated with the aspiration of large amounts of water and the Oxylator failed during the ascent. Efficient ventilation with the MK II full-face mask was also possible only for a short period. An absolutely horizontal position of the manikin was required for successful ventilation, which is likely to be difficult to achieve in open water. Leakage at the sealing lip of the full-face mask and the cuff of the laryngeal tube led to intrusion of water and resulted in subsequent complete failure of ventilation. CONCLUSIONS: The efficacy of underwater ventilation seems to be poor with any of the techniques trialed. Water aspiration frequently makes ventilation impossible and might foster emphysema aquosum-like air trapping and, therefore, increase the risk of pulmonary barotrauma during ascent. Because the limitations of underwater ventilation are substantial even under ideal conditions, it cannot be recommended presently for real diving conditions.

Effectiveness and safety of in-water resuscitation performed by lifeguards and laypersons: a crossover manikin study.

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.

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.

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.

Should children dive with self-contained underwater breathing apparatus (SCUBA)?

UNLABELLED: Diving with self-contained underwater breathing apparatus (SCUBA) has become a popular recreational activity in children and adolescents. This article provides an extensive review of the current literature. CONCLUSIONS: Medical contraindications to SCUBA diving for adults apply to children and adolescents, too, but must be adapted. Additional restrictions to the fitness to dive must apply to both, children and adolescents. Children should always be accompanied by a trained adult when diving.

SCUBA-dive-related changes in heart rate in children.

The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives.