Yeongtak Song

The use of dual accelerometers improves measurement of chest compression depth

BACKGROUND Chest compression (CC) feedback devices are used to perform CC measurements effectively and accurately on patients in hospital beds. However, these devices do not take account of the compression of the mattress, which results in overestimation of CC depth. In this study, we propose a new method using two accelerometers to overcome this limitation and thus measure compression depth more accurately when performing cardiopulmonary resuscitation (CPR) on patients. METHOD One accelerometer was placed on the manikins sternum (a1), and the other between the manikins back and the mattress (a2). The compression depth was calculated by integrating the acceleration twice using a digital signal processing technique. We compared CC depth from dual accelerometers and single accelerometer (a1) on the foam and inflated air mattress with eight CPR providers. RESULT When CC was done on a manikin lying on the floor, there was no significant difference between measurement techniques (p>0.05). When CC was done on a manikin lying on the foam and inflated air mattress supporting system, our method significantly improved the estimation of CC depth, irrespective of the presence or absence of a backboard (p<0.001). CONCLUSION Measuring CC depth using two accelerometers is more effective than using one in increasing the accuracy of CC depth estimation when CPR is performed on the foam and inflated air mattress, regardless of the presence or absence of a backboard.

The development of feedback monitoring device for CPR

CPR (Cardio-Pulmonary Resuscitation) is known as the most basic aid in emergency situations. For successful CPR, the chest compression depth, cycle, and compressing point are important factors. In I.C.U.s (Intensive Care Unit) and E.R.s (Emergency Room), monitoring devices are used to monitor the chest compressions correctly. These devices use accelerometers or pressure sensors. Because the mattress under the patient compresses together, these devices overestimate the compression depth. To overcome this problem, two accelerometers are used in this study, one is on the chest, and the other is between the back of the patient and the mattress. The measurement setup and algorithm to estimate the compression depth are explained. According to the experiment with the mannequin, when CPR is done on a mattress, the actual compression depth was 43.7mm (s.d. 1.93mm). The estimated compression depth was 61.4mm (s.d. 1.87mm) when using an acceleration sensor. This includes the depth of compression of the mattress. When we use two acceleration sensors, estimated compression depth is 44.6mm (s.d. 1.59mm), which is similar to the actual compression depth. In conclusion, the dual accelerometer gives more accurate estimated compression depth than conventional devices.

A novel method to decrease mattress compression during CPR using a mattress compression cover and a vacuum pump

BACKGROUND Mattress compression causes feedback devices to over-estimate the chest compression depth measurement during CPR. We propose a novel method to decrease the mattress compression using a vinyl cover. This mattress compression cover encloses the foam mattress and is compressed by a vacuum pump immediately prior to performing CPR. METHODS Nine CPR providers performed chest compressions on manikins placed on a conventional foam mattress on a bed frame (surface CONV), a backboard and foam mattress on a bed frame (surface BB), and a foam mattress, compressed with a vacuum pump, on a bed frame (surface VAC). Dual accelerometers were used to simultaneously measure the mattress compression and chest compression depths. RESULTS The mattress compression depth levels decreased from 14.9 mm (SD 1.4 mm) on surface CONV to 7.0 mm (SD 0.6 mm) on surface VAC (p<0.001) whereas 14.0 mm (SD 1.3 mm) on surface BB. The total compression depth was 65.4 mm (SD 3.8 mm) on surface CONV, and 58.3 mm (SD 3.0 mm) on surface VAC (p<0.001). CONCLUSION Using a mattress compression cover and a vacuum pump appears to increase the rigidity of the mattress and allow for efficient chest compressions. This novel method could decrease the mattress compression depth and increase the efficiency of chest compression during CPR in hospitals.

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.

Associations among SPARC mRNA expression in adipose tissue, serum SPARC concentration and metabolic parameters in Korean women.

Objective: Secreted protein acidic and rich in cysteine (SPARC) is expressed in most tissues and is also secreted by adipocytes. The associations of SPARC mRNA expression in visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAT), serum SPARC concentration, and metabolic parameters in Korean women are investigated.

Effectiveness of chest compression feedback during cardiopulmonary resuscitation in lateral tilted and semirecumbent positions: a randomised controlled simulation study

Feedback devices have been shown to improve the quality of chest compression during cardiopulmonary resuscitation for patients in the supine position, but no studies have reported the effects of feedback devices on chest compression when the chest is tilted. Basic life support‐trained providers were randomly assigned to administer chest compressions to a manikin in the supine, 30° left lateral tilt and 30° semirecumbent positions, with or without the aid of a feedback device incorporated into a smartphone. Thirty‐six participants were studied. The feedback device did not affect the quality of chest compressions in the supine position, but improved aspects of performance in the tilted positions. In the lateral tilted position, the median (IQR [range]) chest compression rate was 99 (99–100 [96–117]) compressions.min−1 with and 115 (95–128 [77–164]) compressions.min−1 without feedback (p = 0.05), and the proportion of compressions of correct depth was 55 (0–96 [0–100])% with and 1 (0–30 [0–100])% without feedback (p = 0.03). In the semirecumbent position, the proportion of compressions of correct depth was 21 (0–87 [0–100])% with and 1 (0–26 [0–100])% without feedback (p = 0.05). Female participants applied chest compressions at a more accurate rate using the feedback device in the lateral tilted position but were unable to increase the chest compression depth, whereas male participants were able to increase the force of chest compression using the feedback device in the lateral tilted and semirecumbent positions. We conclude that a feedback device improves the application of chest compressions during simulated cardiopulmonary resuscitation when the chest is tilted.

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.

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.

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.

Protection afforded by respirators when performing endotracheal intubation using a direct laryngoscope, GlideScope®, and i-gel® device: A randomized trial

Emergency physicians are at risk of infection during invasive procedures, and wearing a respirator can reduce this risk. The aim of this study was to determine whether the protection afforded by a respirator during intubation is affected by the type of airway device used. In this randomized crossover study, 26 emergency physicians underwent quantitative fit tests for a N95 respirator (cup-type or fold-type) before and during intubation with a direct laryngoscope, GlideScope®, or i-gel® airway device. The primary outcome was the fit factor value of the respirator and the secondary outcome was the level of acceptable protection provided (percentage of fit factor scores above 100). Compared with the GlideScope and i-gel device, the fit factor values and level of acceptable protection provided were lower when physicians wore the cup-type respirator while intubating using the direct laryngoscope (200 fit factor [152–200] and 200 fit factor [121.25–200] versus 166 fit factor [70–200], 100% and 100% versus 75%, respectively; all P < 0.001). There were no significant differences in the fit factor value or level of acceptable protection provided when the physicians wore the fold-type respirator while intubating using any of the three airway devices (all P > 0.05). The type of airway device used for endotracheal intubation may influence the protective performance of some types of respirators. Emergency physicians should consider the effects of airway device types on fit factor of N95 respirators, when they perform intubation at risk of infection.