Adverse drug events leading to emergency department visits: A multicenter observational study in Korea.

Adverse drug events are significant causes of emergency department visits. Systematic evaluation of adverse drug events leading to emergency department visits by age is lacking. This multicenter retrospective observational study evaluated the prevalence and features of adverse drug event-related emergency department visits across ages. We reviewed emergency department medical records obtained from three university hospitals between July 2014 and December 2014. The proportion of adverse drug events among total emergency department visits was calculated. The cause, severity, preventability, and causative drug(s) of each adverse drug event were analyzed and compared between age groups (children/adolescents [<18 years], adults [18-64 years], and the elderly [≥65 years]). Of 59,428 emergency department visits, 2,104 (3.5%) were adverse drug event-related. Adverse drug event-related emergency department visits were more likely to be female and older. Multivariate logistic regression analysis revealed that compared to non- adverse drug event-related cases, adverse drug event-related emergency department visitors were more likely to be female (60.6% vs. 53.6%, p<0.001, OR 1.285, 95% CI 1.025-1.603) and older (50.8 ± 24.6 years vs. 37.7 ± 24.4 years, p<0.001, OR 1.892, 95% CI: 1.397-2.297). Comorbidities such as diabetes, chronic kidney disease, chronic liver disease, and malignancies were also significantly associated with adverse drug event-related emergency department visits. Side effects were the most common type of adverse drug events across age groups, although main types differed substantially depending on age. Serious adverse drug events, hospitalizations, and adverse drug event-related deaths occurred more frequently in the elderly than in adults or children/adolescents. The proportion of adverse drug event-related emergency department visits that were preventable was 15.3%. Causative drugs of adverse drug events varied considerably depending on age group. Adverse drug event features differ substantially according to age group. The findings suggest that an age-specific approach should be adopted in the preventive strategies to reduce adverse drug events.

Association between Glasgow Coma Scale in Early Carbon Monoxide Poisoning and Development of Delayed Neurological Sequelae: A Meta-Analysis.

A significant number of people experience delayed neurologic sequelae after acute carbon monoxide (CO) poisoning. The Glasgow Coma Scale (GCS) can be used to predict delayed neurologic sequelae occurrence efficiently and without any restrictions. Here, we investigated the association between a low GCS score observed in cases of early CO poisoning and delayed neurologic sequelae development through a meta-analysis. We systematically searched MEDLINE, EMBASE, and the Cochrane Library for studies on GCS as a predictor of delayed neurologic sequelae occurrence in patients with CO poisoning in June 2021. Two reviewers independently extracted study characteristics and pooled data. We also conducted subgroup analyses for the cutoff point for GCS. To assess the risk of bias of each included study, we used the quality in prognosis studies tool. We included 2328 patients from 10 studies. With regard to patients with acute CO poisoning, in the overall pooled odds ratio (OR) of delayed neurologic sequelae development, those with a low GCS score showed a significantly higher value and moderate heterogeneity (OR 2.98, 95% confidence interval (CI) 2.10−4.23, I2 = 33%). Additionally, in subgroup analyses according to the cutoff point of GCS, the development of delayed neurologic sequelae was still significantly higher in the GCS < 9 group (OR 2.80, 95% CI 1.91−4.12, I2 = 34%) than in the GCS < 10 or GCS < 11 groups (OR 4.24, 95% CI 1.55−11.56, I2 = 48%). An initial low GCS score in patients with early CO poisoning was associated with the occurrence of delayed neurologic sequelae. Additionally, GCS was quickly, easily, and accurately assessed. It is therefore possible to predict delayed neurologic sequelae and establish an active treatment strategy, such as hyperbaric oxygen therapy, to minimize neurological sequelae using GCS.

Association between Early Phase Serum Lactate Levels and Occurrence of Delayed Neuropsychiatric Sequelae in Adult Patients with Acute Carbon Monoxide Poisoning: A Systematic Review and Meta-Analysis.

The primary goal of treating carbon monoxide (CO) poisoning is preventing or minimizing the development of delayed neuropsychiatric sequelae (DNS). Therefore, screening patients with a high probability for the occurrence of DNS at the earliest is essential. However, prognostic tools for predicting DNS are insufficient, and the usefulness of the lactate level as a predictor is unclear. This systematic review and meta-analysis investigated the association between early phase serum lactate levels and the occurrence of DNS in adult patients with acute CO poisoning. Observational studies that included adult patients with CO poisoning and reported initial lactate concentrations were retrieved from the Embase, MEDLINE, Google Scholar and six domestic databases (KoreaMED, KMBASE, KISS, NDSL, KISTi and RISS) in January 2022. Lactate values were collected as continuous variables and analyzed using standardized mean differences (SMD) using a random-effect model. The risk of bias was evaluated using the Quality in Prognosis Studies (QUIPS) tool, and subgroup, sensitivity and meta regression analyses were performed. Eight studies involving a total of 1350 patients were included. The early phase serum lactate concentration was significantly higher in the DNS group than in the non-DNS group in adult patients with acute CO poisoning (8 studies; SMD, 0.31; 95% CI, 0.11−0.50; I2 = 44%; p = 0.002). The heterogeneity decreased to I2 = 8% in sensitivity analysis (omitting Han2021; 7 studies; SMD, 0.38; 95% CI, 0.23−0.53; I2 = 8%; p < 0.001). The risk of bias was assessed as high in five studies. The DNS group was associated with significantly higher lactate concentration than that in the non-DNS group.

Early neuroimaging and delayed neurological sequelae in carbon monoxide poisoning: a systematic review and meta-analysis.

We aimed to assess the evidence regarding the usefulness of brain imaging as a diagnostic tool for delayed neurological sequelae (DNS) in patients with acute carbon monoxide poisoning (COP). Observational studies that included adult patients with COP and DNS were retrieved from Embase, MEDLINE, and Cochrane Library databases in December 2020 and pooled using a random-effects model. Seventeen studies were systematically reviewed. Eight and seven studies on magnetic resonance imaging (MRI) and computed tomography (CT), respectively, underwent meta-analysis. The pooled sensitivity and specificity of MRI for diagnosis of DNS were 70.9% (95% confidence interval [CI] 64.8-76.3%, I2 = 0%) and 84.2% (95% CI 80.1-87.6%, I2 = 63%), respectively. The pooled sensitivity and specificity of CT were 72.9% (95% CI 62.5-81.3%, I2 = 8%) and 78.2% (95% CI 74.4-87.1%, I2 = 91%), respectively. The areas under the curve for MRI and CT were 0.81 (standard error, 0.08; Q* = 0.74) and 0.80 (standard error, 0.05, Q* = 0.74), respectively. The results indicate that detecting abnormal brain lesions using MRI or CT may assist in diagnosing DNS in acute COP patients.

Development and Evaluation of an Inter-professional Education Course at a Medical School in Korea.

BACKGROUND: Interprofessional collaborative practice (IPCP) is emphasized in medical care for patient safety. As patient care is provided by teams, interprofessional competence is required to ensure the quality and safety of care and should be taught as early as possible. In this study, we introduced a 2-week interprofessional education (IPE) curriculum and attempted to describe and evaluate its effectiveness among medical students. METHODS: We developed a 2-week IPE course and gave it to third- or fourth-year medical students (n = 166) from 2018 to 2019. The curriculum was composed of interactive lectures, discussions, small-group discussions, and simulation and was given to diverse medical students. Students were asked to report their satisfaction with the IPE program, write a reflection paper, and complete readiness for interprofessional learning scale (RIPLS) questionnaires before, immediately after, and 4 months after the curriculum. We also obtained 360° evaluations of the students by other health professionals 1 year after the training. RESULTS: The IPE program changed students' attitudes about interprofessional learning, from less favorable to more favorable. The 360° evaluation by nurses revealed that students became more favored as teammates (overall satisfaction with them as teammates increased from 3.1/5 to 3.4/5) compared to medical interns before IPE training, and complaints from nurses about medical interns were significantly less frequent 1 year after the training. CONCLUSION: The IPE program was effective in preparing medical students for team based collaborative practice even though it was short and exposed once in the curriculum. Further extension to other medical schools is recommended.

310 nm UV-LEDs attenuate imiquimod-induced psoriasis-like skin lesions in C57BL/6 mice and inhibit IL-22-induced STAT3 expression in HaCaT cells.

Ultraviolet light-emitting diodes (UV-LEDs) are a novel light source for phototherapy. This study aimed to evaluate the therapeutic effects of UV-LEDs on psoriasis. Importantly, 310 nm UV-LEDs have not been studied in psoriasis in vitro and in vivo. Effects due to 310 nm UV-LED and 311 nm narrowband ultraviolet B (NBUVB) irradiation were compared for suppressing IL-22-induced activation of STAT3 expression using cell viability assay, western blotting, and immunocytochemistry. C57BL/6 mice were topically treated with imiquimod (IMQ) for 6 consecutive days and degenerative changes were observed. Test groups were irradiated with a 310 nm UV-LED and 311 nm NBUVB. Phenotypic observations, histopathological examinations, and ELISA were conducted with skin and blood samples. STAT3-dependent IL-22 signalling and effects in keratinocytes are negatively regulated by the 310 nm UV-LED, which significantly ameliorated IMQ-induced psoriasis-like dermatitis development and reduced Th17 cytokine levels (IL-17A, IL-22) in serum and dorsal skin. Histopathological findings showed decreases in epidermal thickness and inflammatory T-cell infiltration in the UV-LED-irradiated groups. Quantitative PCR confirmed a UV radiation energy-dependent decrease in IL-17A and IL-22 mRNA levels. The results demonstrated that UV-LEDs had anti-inflammatory and immunoregulatory effects. So, UV-LED phototherapy inhibits psoriasis development by suppressing STAT3 protein and inflammatory cytokines and could be useful in treating psoriasis.

Advantage and Limitation of Using a Visual Feedback Device during Cardiopulmonary Resuscitation Training.

INTRODUCTION: Recent cardiopulmonary resuscitation (CPR) guidelines recommend the use of CPR prompt/feedback devices during CPR training because it can improve the quality of CPR. PROBLEM: Chest compression depth and full chest recoil show a trade-off relationship. Therefore, achievement of both targets (adequate chest compression depth and full chest recoil) simultaneously is a difficult task for CPR instructors. This study hypothesized that introducing a visual feedback device to the CPR training could improve the chest compression depth and ratio of full chest recoil simultaneously. METHODS: The study investigated the effects of introducing a visual feedback device during CPR training by comparing the results of skill tests before and after introducing a visual feedback device. The results of skill tests from 2016 through 2018 were retrospectively reviewed. The strategy of emphasizing chest compression depth was implemented during the CPR training in 2017, and a visual feedback device was introduced in 2018. The interval between the CPR training and skill tests was seven days. Feedback was not provided during the skill tests. RESULTS: In total, 159 students completed skill tests. Although the chest compression depth increased significantly from 50 mm (42-54) to 60 mm (59-61) after emphasizing chest compression depth (P < .001), the ratio of full chest recoil decreased simultaneously from 100% (100-100) to 81% (39-98; P < .001). The ratio of full chest recoil increased significantly from 81% (39-98) to 95% (77-100) after introducing a visual feedback device (P = .018). However, the students who did not achieve 80% of the ratio of full chest recoil remained significantly higher than in 2016 (1% in 2016, 49% in 2017, and 27% in 2018; P < .001). CONCLUSIONS: Although introducing a visual feedback device during CPR training resulted in increasing the ratio of full chest recoil while maintaining the adequacy of chest compression depth, 27% of the students still did not achieve 80% of the ratio of full chest recoil. Another educational strategy should be considered to increase the qualities of CPR more completely.

Effect of metronome guidance on infant cardiopulmonary resuscitation.

This study was conducted to investigate the effect of metronome guidance on the performance of infant cardiopulmonary resuscitation (CPR). A total of 36 medical doctors conducted a 2-min single rescuer CPR with the two-finger technique (TFT) or two-thumb encircling hands technique (TT) on an infant manikin without metronome guidance (baseline test). After completing the baseline test, the participants were assigned to either a "guidance group" or "non-guidance group." The guidance group performed CPR with a high-pitched sound at 110 beats/min from a metronome (test 2), while the non-guidance group performed 2-min CPR without metronome guidance (test 1). Comparison between the results of tests 1 and 2 showed that the ratio of adequate chest compression rate was significantly different in both the TFT (73% [34-93] vs. 98% [95-99], P < 0.001) and the TT (53% [32-79] vs. 99% [98-100], P = 0.010). Other parameters including average depth and the ratio of adequate depth were not significantly different between tests 1 and 2 in both the TFT and TT.Conclusion: Metronome guidance improves the adequacy of chest compression rate during infant CPR without affecting chest compression depth in both the TFT and TT.Trial registration: Clinical Research Information Service, KCT0002735 What is Known: • The rate of chest compressions can be optimized by the use of metronome guidance in pediatric cardiopulmonary resuscitation (CPR). • An adverse effect of deteriorating chest compression depth was found while using a metronome guidance during adult CPR simulations. What is New: • The metronome guidance improved the adequacy of the chest compression rate during infant CPR without affecting other parameters including average depth and the ratio of adequate depth in both the two-finger chest compression technique and two-thumb encircling hand technique.

Irradiation with 310 nm and 340 nm ultraviolet light-emitting-diodes can improve atopic dermatitis-like skin lesions in NC/Nga mice.

Ultraviolet (UV) light produces an immunomodulatory effect on the skin and is widely used for the treatment of chronic inflammatory skin diseases. UV light emitting diodes (UV-LEDs) are a new and promising source of UV radiation. However, their mechanism of action remains largely unknown. In this study, we tested the safety and effectiveness of UV-LED irradiation for the treatment of atopic dermatitis (AD) in an NC/Nga mouse model. Mice were divided into seven groups of eight mice each. Application of Dermatophagoides farinae (Df) extract ointment for four weeks induced AD-like skin lesions. Subsequently, the mice were exposed to UV-LEDs, narrow band UVB, or UVA irradiation three times per week. We assessed the immunosuppressive effects of 310 nm (50 mJ cm-2) and 340 nm (5 J cm-2) UV-LED irradiation. Histological analyses using hematoxylin-eosin, toluidine blue, and immunohistochemical staining were performed. In addition, the serum levels of IgE, inflammatory cytokines and chemokines were measured using enzyme-linked immunosorbent assays (ELISAs). UV-LED irradiation significantly alleviated AD-like skin symptoms, including edema, erythema, dryness, and itching, by modulating Th1 and Th2 responses, transepidermal water loss (TEWL), and scratching behavior in NC/Nga mice. These results suggest that UV-LEDs can improve the treatment of inflammatory skin diseases.

Fractional CO2 laser treatment for vaginal laxity: A preclinical study.

BACKGROUND AND OBJECTIVE: Various studies have investigated treatment for vaginal laxity with microablative fractional carbon dioxide CO2 laser in humans; however, this treatment has not yet been studied in an animal model. Herein, we evaluate the therapeutic effects of fractional CO2 laser for tissue remodeling of vaginal mucosa using a porcine model, with the aim of improving vaginal laxity. STUDY DESIGN/MATERIALS AND METHODS: The fractional CO2 laser enables minimally invasive and non-incisional procedures. By precisely controlling the laser energy pulses, energy is sent to the vaginal canal and the introitus area to induce thermal denaturation and contraction of collagen. We examined the effects of fractional CO2 laser on a porcine model via clinical observation and ultrasound measurement. Also, thermal lesions were histologically examined via hematoxylin-eosin staining, Masson's trichrome staining, and Elastica van Gieson staining and immunohistochemistry. RESULTS: The three treatment groups, which were determined according to the amount of laser-energy applied (60, 90, and 120 mJ), showed slight thermal denaturation in the vaginal mucosa, but no abnormal reactions, such as excessive hemorrhaging, vesicles, or erythema, were observed. Histologically, we also confirmed that the denatured lamina propria induced by fractional CO2 laser was dose-dependently increased after laser treatment. The treatment groups also showed an increase in collagen and elastic fibers due to neocollagenesis and angiogenesis, and the vaginal walls became firmer and tighter because of increased capillary and vessel formation. Also, use of the fractional CO2 laser increased HSP (heat shock protein) 70 and collagen type I synthesis. CONCLUSION: Our results show that microablative fractional CO2 laser can produce remodeling of the vaginal connective tissue without causing damage to surrounding tissue, and the process of mucosa remodeling while under wound dressings enables collagen to increase and the vaginal wall to become thick and tightened. Lasers Surg. Med. 50:940-947, 2018. © 2018 Wiley Periodicals, Inc.

Inter-observer Agreement between Urologists and Radiologists in Interpreting the Computed Tomography Images of Emergency Patients with Renal Colic.

PURPOSE: Low-dose non-enhanced computed tomography (LDCT) has been shown to provide low radiation exposure with proper diagnostic accuracy compared to standard dose non-enhanced computed tomography (SDCT) in patients with renal colic. The goal of our study is to estimate the accuracy of LDCT and SDCT interpretation by emergency medicine residents who primarily treated patients with renal colic. MATERIALS AND METHODS: Thirty sample images of both LDCT and SDCT from renal colic patients were extracted from January 2013 to December 2015 in a tertiary teaching hospital. Five emergency medicine residents interpreted60 image samples over a time span of 3 weeks. The presence of a ureteric stone, the stone's size and location, and signs of obstruction were recorded in the reports. A total of 300 reports were compared with formal readingsby a radiologist. The inter-observer agreement and kappa value were calculated for comparative analysis. RESULTS: Identification of ureteric stones showed almost perfect inter-observer agreement on SDCT (kappa value: 0.93), and the percentage of agreement was 96.7%. However, on LDCT, the inter-observer agreement was substantial (kappa value: 0.73), and the percentage of agreement was 88.0%. CONCLUSION: Using SDCT, emergency medicine residents had almost perfect inter-observer agreement in interpreting the CT images of patients with renal colic compared to a radiologist. However, when using LDCT, they had a lower inter-observer agreement.

Assessment of equivalence of adipose tissue treatment with a noncontact field RF system delivering 200 W for 30 min and 300 W for 20 min: An in vivo porcine study.

BACKGROUND AND AIMS: Abdominal circumferential reduction with noncontact high frequency apoptosis-inducing field RF (AiRF) is becoming very popular. The present study compared the treatment results from two different sets of parameters giving the same dose from the same system in an in vivo porcine model. MATERIALS AND METHODS: Two 10 cm × 10 cm areas were symmetrically marked on both sides of the midline (total of 4 areas) over the rectus abdominis muscle of two anesthetized female micropigs. In Animal A (G1), 27.12 MHz AiRF treatment was given at 200 W for 30 min, and 300 W for 20 min in Animal B (G2). Four sessions were performed at weekly intervals. Gross observation by a veterinary specialist was performed on a daily basis. Temperature measurements (fat and skin), clinical photography and ultrasound imaging were carried out at each session. In addition, blood chemistry was performed before each session to check lipid levels, any adverse changes in markers for liver damage in addition to an enzyme-linked immunosorbent assay (ELISA) for raised levels of TNF-α and IL-1ß. Biopsies were taken and routinely processed for hematoxylin and eosin, Toluidine blue and oil red O stains to examine for tissue damage at baseline and after each treatment. TUNEL assays were performed to check of apoptotic-related DNA damage. Follow-up assessments included photography, ultrasound, ELISA tests and biopsies which were taken regularly up to 90 days after the final treatment. RESULTS: The maximum adipose tissue temperatures at and over the apoptotic threshold of 43°C were reached and maintained in both G1 and G2. The skin surface temperature was slightly higher in G2 after 20 min than in G1 after 30 min, but was still below 43°C. Gross and magnified observation revealed no appreciable differences or thermally-mediated damage between the skin of either of the two groups after the treatments or during the 90-day follow-up period. No lasting erythema or any other adverse event was seen in either group. The liver enzyme markers showed very similar patterns over the 4 weeks of treatment compared with baseline with no levels outside of the normal range. Triglycerides were all within normal rage with no significant differences between the groups. Remarkably similar patterns were noted for the ELISAs in both groups performed over the 4 weeks of treatment and at periods during the 90-day follow-up with no notable abnormal changes in levels. Staining patterns for both G1 and G2 specimens were similar for all stain types during treatment and the 90-day follow-up, showing decreased numbers of adipocytes by the 90-day point. The ultrasound findings revealed a 44.8% and 55.6% decrease in the adipose layer for G1 and G2, respectively, at the 90-day assessment. CONCLUSIONS: The 200 W AiRF treatment for 30 min (G1) and the 300 W AiRF treatment for 20 min (G2) produced very similar results in the porcine model for all assessments and at all assessment points during and up to 90 days after treatment, with slightly better findings suggested for G2. Based on the above findings, the two different settings, delivering the same dose, produced good results with no skin damage and no adverse events. This has implications in busy clinics for AiRF treatment, where the shorter treatment time could represent time saving for the clinic and the patient without compromising safety and giving equal if not better efficacy.

Improving disclosure of medical error through educational program as a first step toward patient safety.

BACKGROUND: Although physicians believe that medical errors should be disclosed to patients and their families, they often hesitate to do so. In this study, we assessed the effectiveness of an education program for medical error disclosure. METHODS: In 2015, six medical interns and 79 fourth-year medical students participated in this study. The education program included practice of error disclosure using a standardized patient scenario, feedback, and short didactic sessions. Participant performance was evaluated with a previously developed rating scale that measures error disclosure performance on five specific component skills. Following education program, we surveyed participant perceptions of medical error disclosure with varying severity of error outcome and their satisfaction with the education program using a 5-point Likert scale. We also surveyed the change of attitude or confidence of participants after education program. RESULTS: The performance score was not significantly different between medical interns and medical students (p = 0.840). Following the education program, 65% of participants said that they had become more confident in coping with medical errors, and most participants (79.7%) were satisfied with the education program. They also indicated that they felt a greater duty to disclose medical errors and deliver an apology when the medical error outcome is more severe. CONCLUSIONS: An education program for disclosing medical errors was helpful in improving confidence in medical error disclosure. Extending the program to more diverse scenarios and a more diverse group of physicians is needed.

Out-of-hospital cardiopulmonary resuscitation strategies using one-handed chest compression technique for children suffering a cardiac arrest.

OBJECTIVE: We evaluated the decrease in chest compression depth during 30 : 2 compression-to-ventilation ratio one-handed chest compression (OHCC) in an out-of-hospital pediatric arrest setting, and whether switching hands every other cycle could maintain compression depth. METHODS: A 5-year-old child-sized manikin was used, and 50 medical students participated in the present study. First, the participants performed 5 min OHCC with a 30 : 2 compression-to-ventilation ratio on the floor (baseline test). Second, the compression technique was changed from the OHCC to the two-handed chest compression when they became subjectively fatigued (test 1). Third, the compression hand was alternated every other cycle (test 2). Average compression depth (ACD) data were recorded using an accelerometer device. RESULTS: ACD changed significantly during the baseline test (0-1 min: 44.5±5.3 mm, 1-2 min: 43.7±6.1 mm, 2-3 min: 43.4±6.5 mm, 3-4 min: 43.2±6.5 mm, and 4-5 min: 42.3±6.5 mm, P=0.012). However, no significant differences were observed during test 1 or test 2. The baseline ACD value for the 4-5-min interval [95% confidence interval (CI), 40.5-44.2 mm] was significantly lower than those in test 1 (95% CI, 43.0-45.9 mm, P=0.004) and test 2 (95% CI, 42.4-45.9 mm, P=0.004). No differences in the ACDs at any interval were observed between test 1 and test 2. CONCLUSION: Compression depth decreased significantly after 4 min during 30 : 2 ratio OHCC. However, it was maintained by changing from the OHCC to the two-handed chest compression or by alternating compression hands every other cycle.

Relationship between chest compression depth and novice rescuer body weight during cardiopulmonary resuscitation.

OBJECTIVE: This study determined if rescuer body weight is a major determinant of chest compression depth (CCD) among novice rescuers by analyzing the results of cardiopulmonary resuscitation (CPR) skill tests among medical students and determined the body weight threshold for those unable to achieve adequate CCD. METHODS: Retrospective analysis of CPR test results was performed. A total of 107 medical students completed the tests, which included 5 cycles of CPR. Data were collected using a ResusciAnne SkillReporter. Anthropometric data including participant body weight, body mass index, and height were also collected. The relationships between CCD and anthropometric data were evaluated by Pearson correlation coefficient. In addition, univariate linear regression analysis was used to assess the association between body weight and CCD. RESULTS: The highest positive correlation was found between CCD and body weight (r = 0.636, P < .001). Body weight correlated with CCD by as much as 40.5% (R2 = 40.5, P < .001). Using a regression model, we described the association between body weight and CCD as follows: expected CCD (mm) = 0.46 × body weight + 17.59. The regression equation shows that rescuers weighing more than 70.5 kg could achieve a CCD of 50 mm. CONCLUSIONS: Rescuer body weight is a major determinant of CCD in novice rescuers. Based on these findings, if 2 or more rescuers are available to perform CPR, chest compression should preferentially be performed by rescuers of healthy weight or overweight.