Measurement and Correction of Stooped Posture during Gait Using Wearable Sensors in Patients with Parkinsonism: A Preliminary Study.

Stooped posture, which is usually aggravated during walking, is one of the typical postural deformities in patients with parkinsonism. However, the degree of stooped posture is difficult to quantitatively measure during walking. Furthermore, continuous feedback on posture is also difficult to provide. The purpose of this study is to measure the degree of stooped posture during gait and to investigate whether vibration feedback from sensor modules can improve a patient's posture. Parkinsonian patients with stooped posture were recruited for this study. Two wearable sensors with three-axis accelerometers were attached, one at the upper neck and the other just below the C7 spinous process of the patients. After being calibrated in the most upright posture, the sensors continuously recorded the sagittal angles at 20 Hz and averaged the data at every second during a 6 min walk test. In the control session, the patients walked with the sensors as usual. In the vibration session, sensory feedback was provided through vibrations from the neck sensor module when the sagittal angle exceeded a programmable threshold value. Data were collected and analyzed successfully in a total of 10 patients. The neck flexion and back flexion were slightly aggravated during gait, although the average change was <10° in most patients in both measurement sessions. Therefore, it was difficult to evaluate the effect of sensory feedback through vibration. However, some patients showed immediate response to the feedback and corrected their posture during gait. In conclusion, this preliminary study suggests that stooped posture could be quantitatively measured during gait by using wearable sensors in patients with parkinsonism. Sensory feedback through vibration from sensor modules may help in correcting posture during gait in selected patients.

Automatic Classification of Squat Posture Using Inertial Sensors: Deep Learning Approach.

Without expert coaching, inexperienced exercisers performing core exercises, such as squats, are subject to an increased risk of spinal or knee injuries. Although it is theoretically possible to measure the kinematics of body segments and classify exercise forms with wearable sensors and algorithms, the current implementations are not sufficiently accurate. In this study, the squat posture classification performance of deep learning was compared to that of conventional machine learning. Additionally, the location for the optimal placement of sensors was determined. Accelerometer and gyroscope data were collected from 39 healthy participants using five inertial measurement units (IMUs) attached to the left thigh, right thigh, left calf, right calf, and lumbar region. Each participant performed six repetitions of an acceptable squat and five incorrect forms of squats that are typically observed in inexperienced exercisers. The accuracies of squat posture classification obtained using conventional machine learning and deep learning were compared. Each result was obtained using one IMU or a combination of two or five IMUs. When employing five IMUs, the accuracy of squat posture classification using conventional machine learning was 75.4%, whereas the accuracy using deep learning was 91.7%. When employing two IMUs, the highest accuracy (88.7%) was obtained using deep learning for a combination of IMUs on the right thigh and right calf. The single IMU yielded the best results on the right thigh, with an accuracy of 58.7% for conventional machine learning and 80.9% for deep learning. Overall, the results obtained using deep learning were superior to those obtained using conventional machine learning for both single and multiple IMUs. With regard to the convenience of use in self-fitness, the most feasible strategy was to utilize a single IMU on the right thigh.

Wearable Sensor Based Stooped Posture Estimation in Simulated Parkinson's Disease Gaits.

Stooping is a posture which is described as an involuntary forward bending of the thoracolumbar spine. Conventionally, the stooped posture (SP) in Parkinson's disease patients is measured in static or limited movement conditions using a radiological or optoelectronic system. In the dynamic condition with long movement distance, there was no effective method in preference to the empirical assessment from doctors. In this research, we proposed a practical method for estimating the SP with a high accuracy where accelerometers can be mounted on the neck or upper back as a wearable sensor. The experiments with simulated subjects showed a high correlation of 0.96 and 0.99 between the estimated SP angle and the reference angles for neck and back sensor position, respectively. The maximum absolute error (0.9 and 1.5 degrees) indicated that the system can be used, not only in clinical assessment as a measurement, but also in daily life as a corrector.

A Virtual Blind Cane Using a Line Laser-Based Vision System and an Inertial Measurement Unit.

A virtual blind cane system for indoor application, including a camera, a line laser and an inertial measurement unit (IMU), is proposed in this paper. Working as a blind cane, the proposed system helps a blind person find the type of obstacle and the distance to it. The distance from the user to the obstacle is estimated by extracting the laser coordinate points on the obstacle, as well as tracking the system pointing angle. The paper provides a simple method to classify the obstacle's type by analyzing the laser intersection histogram. Real experimental results are presented to show the validity and accuracy of the proposed system.

Clinical application of real-time tele-ultrasonography in diagnosing pediatric acute appendicitis in the ED.

PURPOSE: We investigated the effectiveness of tele-mentored ultrasonography between emergency medicine (EM) residents and remote experts in diagnosing acute appendicitis. METHODS: This prospective observational study was performed in an academic emergency department. Beginning in June 2014, the EM residents performed the initial ultrasonography for suspected pediatric acute appendicitis; then, the remote experts observed/mentored the residents' practice using the tele-ultrasonography system; and finally, an onsite expert verified the diagnosis. The diagnostic confidence of each examiner (resident, remote expert, and onsite expert) was rated on a 5-point Likert scale. The appendix identification rate and the diagnostic values; sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for each type of examination were calculated. RESULTS: A total of 115 pediatric cases with suspected acute appendicitis, including 36 with pathology-confirmed acute appendicitis, between June 2014 and February 2015 were enrolled in this study. In 9 of the 115 (7.8%) cases, a non-appendicitis diagnosis was determined in the absence of the successful identification of a normal appendix upon resident examination. Of these, seven appendices were identified upon expert tele-ultrasonography. The diagnostic values for expert tele-ultrasonography were higher (sensitivity: 1.000, specificity: 0.975, PPV: 0.947, NPV: 1.000) than those for resident-performed ultrasonography (sensitivity: 0.917, specificity: 0.899, PPV: 0.805, NPV: 0.959) and similar to those for onsite expert-performed ultrasonography (sensitivity: 1.000, specificity: 0.987, PPV: 0.973, NPV: 1.000). CONCLUSION: Tele-ultrasonography with tele-mentoring between EM residents and experienced mentors was effectively applied in diagnosing pediatric acute appendicitis in an emergency clinical setting.

Proper target depth of an accelerometer-based feedback device during CPR performed on a hospital bed: a randomized simulation study.

PURPOSE: Feedback devices are used to improve chest compression (CC) quality related to survival rates in cardiac arrest. However, several studies have shown that feedback devices are not sufficiently reliable to ensure adequate CC depth on soft surfaces. Here, we determined the proper target depth of feedback (TDF) using an accelerometer during cardiopulmonary resuscitation in hospital beds. METHODS: In prospective randomized crossover study, 19 emergency physicians performed CCs for 2 minutes continuously on a manikin in 2 different beds with 3 TDFs (5, 6, and 7 cm). We measured CC depth, the proportion of accurate compression depths, CC rate, the proportion of incomplete chest decompressions, the velocity of CC (CC velocity), the proportion of time spent in CC relative to compression plus decompression (duty cycle), and the time spent in CC (CC time). RESULTS: Mean (SD) CC depths at TDF 5, 6, and 7 were 45.42 (5.79), 52.68 (4.18), and 58.47 (2.48) on one bed and 46.26 (4.49), 53.58 (3.15), and 58.74 (2.10) mm on the other bed (all P<.001), respectively. The proportions of accurate compression depths and CC velocity at TDF 5, 6, and 7 differed significantly according to TDF on both beds (all P<.001).The CC rate, CC time, and proportion of incomplete chest decompression did not differ on both beds (all P>.05). The duty cycle differed significantly on only B2. CONCLUSIONS: The target depth of the real-time feedback device should be at least 6 cm but should not exceed 7 cm for optimal CC on patients on hospital beds.

A new chest compression depth feedback algorithm for high-quality CPR based on smartphone.

BACKGROUND: Although many smartphone application (app) programs provide education and guidance for basic life support, they do not commonly provide feedback on the chest compression depth (CCD) and rate. The validation of its accuracy has not been reported to date. This study was a feasibility assessment of use of the smartphone as a CCD feedback device. In this study, we proposed the concept of a new real-time CCD estimation algorithm using a smartphone and evaluated the accuracy of the algorithm. MATERIALS AND METHODS: Using the double integration of the acceleration signal, which was obtained from the accelerometer in the smartphone, we estimated the CCD in real time. Based on its periodicity, we removed the bias error from the accelerometer. To evaluate this instrument's accuracy, we used a potentiometer as the reference depth measurement. The evaluation experiments included three levels of CCD (insufficient, adequate, and excessive) and four types of grasping orientations with various compression directions. We used the difference between the reference measurement and the estimated depth as the error. The error was calculated for each compression. RESULTS: When chest compressions were performed with adequate depth for the patient who was lying on a flat floor, the mean (standard deviation) of the errors was 1.43 (1.00) mm. When the patient was lying on an oblique floor, the mean (standard deviation) of the errors was 3.13 (1.88) mm. CONCLUSIONS: The error of the CCD estimation was tolerable for the algorithm to be used in the smartphone-based CCD feedback app to compress more than 51 mm, which is the 2010 American Heart Association guideline.

Videographic analysis of glottic view with increasing cricoid pressure force.

STUDY OBJECTIVE: Cricoid pressure may negatively affect laryngeal view and compromise airway patency, according to previous studies of direct laryngoscopy, endoscopy, and radiologic imaging. In this study, we assess the effect of cricoid pressure on laryngeal view with a video laryngoscope, the Pentax-AWS. METHODS: This cross-sectional survey involved 50 American Society of Anesthesiologists status I and II patients who were scheduled to undergo elective surgery. The force measurement sensor for cricoid pressure and the video recording system using a Pentax-AWS video laryngoscope were newly developed by the authors. After force and video were recorded simultaneously, 11 still images were selected per 5-N (Newton; 1 N = 1 kg·m·s(-2)) increments, from 0 N to 50 N for each patient. The effect of cricoid pressure was assessed by relative percentage compared with the number of pixels on an image at 0 N. RESULTS: Compared with zero cricoid pressure, the median percentage of glottic view visible was 89.5% (interquartile range [IQR] 64.2% to 117.1%) at 10 N, 83.2% (IQR 44.2% to 113.7%) at 20 N, 76.4% (IQR 34.1% to 109.1%) at 30 N, 51.0% (IQR 21.8% to 104.2%) at 40 N, and 47.6% (IQR 15.2% to 107.4%) at 50 N. The number of subjects who showed unworsened views was 20 (40%) at 10 N, 17 (34%) at 20 and 30 N, and 13 (26%) at 40 and 50 N. CONCLUSION: Cricoid pressure application with increasing force resulted in a worse glottic view, as examined with the Pentax-AWS Video laryngoscope. There is much individual difference in the degree of change, even with the same force. Clinicians should be aware that cricoid pressure affects laryngeal view with the Pentax-AWS and likely other video laryngoscopes.

A novel method to position an endotracheal tube at the correct depth using an infrared sensor stylet.

PURPOSE: This study is a feasibility assessment to determine the ability of novice users to utilize an infrared (IR) sensor stylet as a guide to position the tip of the endotracheal tube (ETT) 40 mm proximal to the carina in the swine trachea. METHODS: We developed a stylet system using an IR sensor attached to the tip of a stylet to facilitate measuring the distance of the ETT from the carina. The indicator lamp of the IR sensor system turns on through calibration when the ETT tip arrives at a point 20 mm proximal to the carina. In order to place the ETT tip 40 mm (middle of 20-60 mm) from the carina after the indicator lamp turns on, the operator uses the ETT marker to withdraw the ETT 20 mm. For this study, five fresh swine airways were used in random order after drawing lots, and ten novices were recruited to attempt the procedure ten times on each swine's airway. RESULTS: Five hundred endotracheal intubations were performed. For the target distance of 40 mm from the ETT tip to the carina, the mean (standard deviation) of the total data set was 37.9 (3.5) mm; all data were within a 20-60 mm range (500/500), and 98.2% (491/500) of the attempts fell within the 30-50 mm range. CONCLUSIONS: The IR sensor stylet system can facilitate correct positioning of the ETT tip at an appropriate depth above the carina in the swine trachea. Evaluation of the IR sensor stylet methodology in human subjects is warranted.

Use of backboard and deflation improve quality of chest compression when cardiopulmonary resuscitation is performed on a typical air inflated mattress configuration.

No study has examined the effectiveness of backboards and air deflation for achieving adequate chest compression (CC) depth on air mattresses with the typical configurations seen in intensive care units. To determine this efficacy, we measured mattress compression depth (MCD, mm) on these surfaces using dual accelerometers. Eight cardiopulmonary resuscitation providers performed CCs on manikins lying on 4 different surfaces using a visual feedback system. The surfaces were as follows: A, a bed frame; B, a deflated air mattress placed on top of a foam mattress laid on a bed frame; C, a typical air mattress configuration with an inflated air mattress placed on a foam mattress laid on a bed frame; and D, C with a backboard. Deflation of the air mattress decreased MCD significantly (B; 14.74 ± 1.36 vs C; 30.16 ± 3.96, P < 0.001). The use of a backboard also decreased MCD (C; 30.16 ± 3.96 vs D; 25.46 ± 2.89, P = 0.002). However, deflation of the air mattress decreased MCD more than use of a backboard (B; 14.74 ± 1.36 vs D; 25.46 ± 2.89, P = 0.002). The use of a both a backboard and a deflated air mattress in this configuration reduces MCD and thus helps achieve accurate CC depth during cardiopulmonary resuscitation.

Rotation aiding technique for endobronchial ultrasound-guided transbronchial needle aspiration biopsy of intrathoracic lymph nodes: A complementary approach to the conventional jabbing method.

BACKGROUND: This study aimed to compare the lymph node core tissue lengths obtained via mediastinal or hilar lymphadenopathy using the complementary "rotation aiding" and conventional Jab technique. METHODS: We prospectively measured the lymph node core tissue length in patients who sequentially underwent the Jab and rotation aiding (RA) techniques between October 2012 and December 2014. Wilcoxon signed-rank test was used to compare the core tissue length and grade of diagnostic cells obtained by each technique. McNemar's test was used to compare the proportion of adequate cellularity (≥grade 2) between the aspiration techniques. RESULTS: The core tissue length of 61 lymph nodes from 43 patients (mean age: 63 years, range: 16-86 years) was analyzed. Pathological findings were consistent with malignant lesions in 25 (41%) patients and benign lesions in 36 (59%). The most common diagnosis in benign lymph nodes was reactive, followed by tuberculosis and sarcoidosis. We obtained longer core tissue with RA technique than with the Jab technique (83.2 ± 12.7 vs. 60.1 ± 10.1 mm; p = 0.02). There was a significant increase in cellularity grade and proportion of ≥grade 2 cells with the RA technique than with the Jab technique (2.39 ± 1.08 vs. 1.84 ± 1.14; p < 0.001, 78.7% vs. 52.5%; p = 0.002), regardless of the pathological diagnosis. CONCLUSIONS: RA technique facilitated more lymph node samples in terms of core tissue length and cellularity than the Jab technique.

What muscles need to be trained for high-quality chest compression?

BACKGROUND: This study is aimed to identify the muscles that need to be trained for high-quality cardiopulmonary resuscitation by evaluating the muscles that are fatigued during chest compression in both kneeling and standing positions. METHODS: In this randomized crossover trial, 37 participants performed continuous chest compressions on a manikin for 5min, alternating between kneeling and standing positions. The median frequency values of 16 muscles were determined from surface electromyography recordings. RESULTS: The median frequency values of the arm muscles (flexor carpi radialis, extensor carpi radialis, biceps brachii, triceps brachii) in both positions were significantly lower during the last 30s than during the first 30s, demonstrating muscle fatigue over time. The cervical erector spinae in the kneeling position and the external oblique abdominis in the standing position were also fatigued over time. In the deltoideus, quadriceps femoris, and biceps femoris muscles, the difference in median frequency between the last 30s and the first 30s was significantly different between the two positions, and muscles were more fatigued in the standing position than in the kneeling position. CONCLUSIONS: Understanding patterns of muscle fatigue and training of these muscles would assist healthcare providers in performing high-quality chest compressions. ClinicalTrials.gov number: NCT02088879.

Smartwatch feedback device for high-quality chest compressions by a single rescuer during infant cardiac arrest: a randomized, controlled simulation study.

OBJECTIVE: According to the guidelines, rescuers should provide chest compressions (CC) ~1.5 inches (40 mm) for infants. Feedback devices could help rescuers perform CC with adequate rates (CCR) and depths (CCD). However, there is no CC feedback device for infant cardiopulmonary resuscitation (CPR). We suggest a smartwatch-based CC feedback application for infant CPR. PARTICIPANTS AND METHODS: We created a smartwatch-based CC feedback application. This application provides feedback on CCD and CCR by colour and text for infant CPR. To evaluate the application, 30 participants were divided randomly into two groups on the basis of whether CC was performed with or without the assistance of the smartwatch application. Both groups performed continuous CC-only CPR for 2 min on an infant mannequin placed on a firm table. We collected CC parameters from the mannequin, including the proportion of correct depth, CCR, CCD and the proportion of correct decompression depth. RESULTS: Demographics between the two groups were not significantly different. The median (interquartile range) proportion of correct depth was 99 (97-100) with feedback compared with 83 (58-97) without feedback (P = 0.002). The CCR and proportion of correct decompression depth were not significantly different between the two groups (P = 0.482 and 0.089). The CCD of the feedback group was significantly deeper than that of the control group [feedback vs. control: 41.2 (39.8-41.7) mm vs. 38.6 (36.1-39.6) mm; P=0.004]. CONCLUSION: Rescuers who receive feedback of CC parameters from a smartwatch could perform adequate CC during infant CPR.

Effectiveness of feedback with a smartwatch for high-quality chest compressions during adult cardiac arrest: A randomized controlled simulation study.

Previous studies have demonstrated the potential for using smartwatches with a built-in accelerometer as feedback devices for high-quality chest compression during cardiopulmonary resuscitation. However, to the best of our knowledge, no previous study has reported the effects of this feedback on chest compressions in action. A randomized, parallel controlled study of 40 senior medical students was conducted to examine the effect of chest compression feedback via a smartwatch during cardiopulmonary resuscitation of manikins. A feedback application was developed for the smartwatch, in which visual feedback was provided for chest compression depth and rate. Vibrations from smartwatch were used to indicate the chest compression rate. The participants were randomly allocated to the intervention and control groups, and they performed chest compressions on manikins for 2 min continuously with or without feedback, respectively. The proportion of accurate chest compression depth (≥5 cm and ≤6 cm) was assessed as the primary outcome, and the chest compression depth, chest compression rate, and the proportion of complete chest decompression (≤1 cm of residual leaning) were recorded as secondary outcomes. The proportion of accurate chest compression depth in the intervention group was significantly higher than that in the control group (64.6±7.8% versus 43.1±28.3%; p = 0.02). The mean compression depth and rate and the proportion of complete chest decompressions did not differ significantly between the two groups (all p>0.05). Cardiopulmonary resuscitation-related feedback via a smartwatch could provide assistance with respect to the ideal range of chest compression depth, and this can easily be applied to patients with out-of-hospital arrest by rescuers who wear smartwatches.

Smartwatches as chest compression feedback devices: A feasibility study.

BACKGROUND: Recently, there have been attempts to use smartphones and smartwatches as the feedback devices to improve the quality of chest compressions. In this study, we compared chest compression depth feedback accuracy between a smartphone and a smartwatch in a hands-only cardiopulmonary resuscitation scenario, using a manikin with a displacement sensor system. METHODS: Ten basic life support providers participated in this study. Guided by the chest compression depths displayed on the monitor of a laptop, which received data from the manikin, each participant performed 2min of chest compressions for each target depth (35mm and 55mm) on a manikin while gripping a smartphone and wearing a smartwatch. Participants had a rest of 1h between the instances, and the first target depth was set at random. Each chest compression depth data value from the smartphone and smartwatch and a corresponding reference value from the manikin with the displacement system were recorded. To compare the accuracy between the smartphone and smartwatch, the errors, expressed as the absolute of the differences between the reference and each device, were calculated. RESULTS: At both target depths, the error of the smartwatch were significantly smaller than that of the smartphone (the errors of the smartphone vs. smartwatch at 35mm: 3.4 (1.3) vs. 2.1 (0.8) mm; p=0.008; at 55mm: 5.3 (2.8) vs. 2.3 (0.9) mm; p=0.023). CONCLUSION: The smartwatch-based chest compression depth feedback was more accurate than smartphone-based feedback.

Training a Chest Compression of 6-7 cm Depth for High Quality Cardiopulmonary Resuscitation in Hospital Setting: A Randomised Controlled Trial.

PURPOSE: During cardiopulmonary resuscitation (CPR), chest compression (CC) depth is influenced by the surface on which the patient is placed. We hypothesized that training healthcare providers to perform a CC depth of 6-7 cm (instead of 5-6 cm) on a manikin placed on a mattress during CPR in the hospital might improve their proper CC depth. MATERIALS AND METHODS: This prospective randomised controlled study involved 66 premedical students without CPR training. The control group was trained to use a CC depth of 5-6 cm (G 5-6), while the experimental group was taught to use a CC depth of 6-7 cm (G 6-7) with a manikin on the floor. All participants performed CCs for 2 min on a manikin that was placed on a bed 1 hour and then again 4 weeks after the training without a feedback. The parameters of CC quality (depth, rate, % of accurate depth) were assessed and compared between the 2 groups. RESULTS: Four students were excluded due to loss to follow-up and recording errors, and data of 62 were analysed. CC depth and % of accurate depth were significantly higher among students in the G 6-7 than G 5-6 both 1 hour and 4 weeks after the training (p<0.001), whereas CC rate was not different between two groups (p>0.05). CONCLUSION: Training healthcare providers to perform a CC depth of 6-7 cm could improve quality CC depth when performing CCs on patients who are placed on a mattress during CPR in a hospital setting.

Evaluation of masseter muscle electromyography after surgical extraction of third molar.

PURPOSE: The aims of this study were to evaluate the results of electromyographies (EMGs) of the masseter muscle after mandibular third molar surgery and to determine the relationships between clinical variables and EMG results. PATIENTS AND METHODS: Seventy patients were included in the study. The parameters of the patients' masseter muscles were measured using EMG prior to operation and 7 and 21 days post-operation. Clinical variables were also recorded before and after the third molar surgeries. RESULTS: When the masseter muscle EMG results from the tooth-extracted side were compared with those from the non-extracted (control) side, significant differences in the areas of voltage, power spectral densities and median frequencies (p = 0.011, 0.017 and 0.041, respectively) were found 7 days postoperatively. Additionally, there were significant associations between some clinical variables (i.e. postoperative swelling, bone reduction and pericoronitis) and the EMG results 7 days postoperatively, (p < 0.05). However, there were no significant differences 21 days postoperatively. CONCLUSION: This study revealed that the postoperative changes in EMG activities were transient. Although there have been controversies about the reliability of EMG, this study showed that some EMG variables could be used to evaluate postoperative changes in masseter muscle activity.

High-fidelity digital recording and playback sphygmomanometry system: device description and proof of concept.

OBJECTIVES: This study describes the development of a new digital sphygmocorder (DS-II), which allows the digital recording and playback of the Korotkoff sounds, together with cuff pressure waveform, and its performance in a pilot validation study. MATERIALS AND METHODS: A condenser microphone and stethoscope head detect Korotkoff sounds and an electronic chip, dedicated to audio-signal processing, is used to record high-quality sounds. Systolic and diastolic blood pressure (SBP/DBP) are determined from the recorded signals with an automatic beat detection algorithm that displays the cuff pressure at each beat on the monitor. Recordings of Korotkoff sounds, with the cuff pressure waveforms, and the simultaneous on-site assessments of SBP/DBP were performed during 100 measurements in 10 individuals. The observers reassessed the recorded signals to verify their accuracy and differences were calculated. RESULTS: The features of the high-fidelity DS-II, the technical specifications and the assessment procedures utilizing the playback software are described. Interobserver absolute differences (mean±SD) in measurements were 0.7±1.1/1.3±1.3 mmHg (SBP/DBP) with a mercury sphygmomanometer and 0.3±0.9/0.8±1.2 mmHg with the DS-II. The absolute DS-II mercury sphygmomanometer differences were 1.3±1.9/1.5±1.3 mmHg (SBP/DBP). CONCLUSION: The high-fidelity DS-II device presents satisfactory agreement with simultaneous measurements of blood pressure with a mercury sphygmomanometer. The device will be a valuable methodology for validating new blood pressure measurement technologies and devices.

Chest compression with kneeling posture in hospital cardiopulmonary resuscitation: A randomised crossover simulation study.

PURPOSE: We suggest an alternative chest compression (CC) in kneeling posture using a 'kneeling stool' on which the performer kneels beside the patient on a bed in-hospital. In kneeling posture, we can maintain high quality cardiopulmonary resuscitation (CPR) without the bed height adjustment, which is necessary and inconvenient in standing posture. METHODS: This study is a randomised crossover trial with 38 participants working in one ED. The first group knelt on the kneeling stool beside a manikin placed on a bed, whereas the second group stood on a step stool with the manikin at knee level using bed height adjustment. All the participants performed continuous chest compression for 5 min without audio-visual feedback. After that, the posture was changed in each group. The parameters of CC quality (CC depth, rate, accuracy, and incomplete chest recoil), visual analogue scale (VAS) for fatigue and pain, and preference of participants were compared between the two groups. RESULTS: The data of 33 participants in both postures were analysed following exclusion of five participants. In the comparisons overall and per minute between the two postures, the parameters and VAS do not differ significantly (all P > 0.05) except for the median 1st CC rate that was faster in kneeling posture than in standing posture, P = 0.01). Twenty-three performers preferred the kneeling posture. CONCLUSIONS: A kneeling posture with a kneeling stool were preferred by participants, which have shown similar results in CC parameters and VAS with a standing posture on a stepstool with bed height adjustment during in-hospital CPR.