Association Between QRS Characteristics in Pulseless Electrical Activity and Survival Outcome in Cardiac Arrest Patients: A Systematic Review and Meta-Analysis.

OBJECTIVE: Recent studies have shown inconsistent results regarding the association between QRS characteristics and survival outcomes in patients with cardiac arrest and pulseless electrical activity (PEA) rhythms. This meta-analysis aimed to identify the usefulness of QRS width and frequency as prognostic tools for outcomes in patients with cardiac arrest and PEA rhythm. METHODS: Extensive searches were conducted using Medline, Embase, and the Cochrane Library to find articles published from database inception to 4 June 2023. Studies that assessed the association between the QRS characteristics of cardiac arrest patients with PEA rhythm and survival outcomes were included. The Newcastle-Ottawa Scale was used to assess the methodological quality of the included studies. RESULTS: A total of 9727 patients from seven observational studies were included in this systematic review and meta-analysis. The wide QRS group (QRS ≥ 120 ms) was associated with significantly higher odds of mortality than the narrow QRS group (QRS < 120 ms) (odds ratio (OR) = 1.86, 95% confidence interval (CI) = 1.11-3.11, I2 = 58%). The pooled OR for mortality was significantly higher in patients with a QRS frequency of < 60/min than in those with a QRS frequency of ≥ 60/min (OR = 1.90, 95% CI = 1.19-3.02, I2 = 65%). CONCLUSIONS: Wide QRS width or low QRS frequency is associated with increased odds of mortality in patients with PEA cardiac arrest. These findings may be beneficial to guide the disposition of cardiac arrest patients with PEA during resuscitation.

Impact of extent of resection and postoperative radiotherapy on survival outcomes in intracranial solitary fibrous tumors: a systematic review and meta-analysis.

The knowledge of optimal treatments for patients with intracranial solitary fibrous tumor (SFT) is limited, with inconclusive results from previous studies. In this study, we conducted a meta-analysis of relevant studies to identify the prognostic impact of the extent of resection (EOR) and postoperative radiotherapy (PORT) on survival outcomes of patients with intracranial SFT. We searched the Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) to identify relevant studies published till April 2022. Progression-free survival (PFS) and overall survival (OS) were the outcomes of interest. Differences between two cohorts (gross total resection [GTR] vs. subtotal resection [STR] and PORT vs. surgery only) were estimated by calculating hazard ratios. Twenty-seven studies were selected for the meta-analysis, including data of 1348 patients (GTR, n = 819 vs. STR, n = 381 and PORT, n = 723 vs. surgery only, n = 578). Pooled hazard ratios of PFS (1, 3, 5, and 10 years) and OS (3, 5, and 10 years) revealed that the GTR cohort showed sustained superiority over the STR cohort. In addition, the PORT cohort was superior to the surgery-only cohort with respect to all PFS periods. Although the 10-year OS between the two cohorts was not statistically different, PORT showed significantly better 3- and 5-year OS than surgery only. The study findings suggest that GTR and PORT provide significant benefits for PFS and OS. Aggressive surgical resection of tumors to achieve GTR followed by PORT should be implemented as optimal treatments for all patients with intracranial SFT when feasible.

Distribution of the tensor of the vastus intermedius.

The tensor of the vastus intermedius (TVI) was first described by Grob et al. in 2016. It originates from the anteroinferior greater trochanter and inserts into the upper patella and receives blood and nerves independently of other muscles. It has been overlooked, but since micro-surgery and detailed rehabilitation treatments are being developed, more research on it is warranted. Here we report on the TVI in a Korean cadaveric study. A total of 58 cadavers (41 males and 17 females) were included. Thighs were examined using a standardized dissection protocol. The quadriceps femoris muscle was identified and its components were defined by blunt dissection. A total of 116 lower limbs were dissected. In 40 of them, there was a separately innervated TVI muscle belly between the fasciae of the vastus lateralis (VL) and the vastus intermedius (VI) muscles. TVIs were classed as independent (ID), VI, and VL types according to the relative relationship between the TVI, VL, and VI, and subdivided into two parts: Part 1 was the proximal muscular portion of the TVI attached to the VL or VI, and part 2 was the distal aponeurotic area. TVIs were analyzed in detail via 58 Korean cadavers. We subdivided them on the basis of their location and association with related muscles. A larger study is needed to clarify the function and prevalence of the TVI.

Anatomical Characteristics of the Anterior Jugular Vein and Its Clinical Relevance.

INTRODUCTION: The anterior jugular vein (AJV) is part of the superficial venous drainage system of the head and neck. Recently, interest in AJV is increasing as various surgical procedures have been developed. The authors conducted a cadaveric study to determine characteristics of AJV in Koreans. METHODS: A total of 44 cadavers were dissected. Anatomical characteristics were analyzed for 34 cadavers in which AJV was well observed. RESULTS: In this study, 21 were males and 13 were females. There were 8 cadavers with only 1 AJV from both sides. There was no significant difference in anatomical characteristics according to gender or AJV variation except for a difference in the length of the neck according to gender. However, it was possible to find a safety zone at the main landmark of the neck that could avoid AJV damage. CONCLUSIONS: By using this safety zone, it is possible to prevent damage to the AJV and reduce complications during various surgical procedures on the head and neck.

Diagnostic Accuracy of Ischemia-Modified Albumin for Acute Coronary Syndrome: A Systematic Review and Meta-Analysis.

The diagnostic usefulness of ischemia-modified albumin in acute coronary syndrome (ACS) has been questioned. The goal of this systematic review and meta-analysis was to see how accurate ischemia-modified albumin (IMA) was in diagnosing ACS in patients admitted to emergency departments (EDs). We searched for relevant literature in databases such as MEDLINE, EMBASE, and the Cochrane Library. Primary studies that reliably reported on patients with symptoms suggestive of ACS and evaluated IMA on admission to emergency departments were included. The QUADAS-2 tool was used to assess the risk of bias in the included research. A total of 4,761 patients from 19 studies were included in this systematic review. The sensitivity and specificity were 0.74 and 0.40, respectively, when the data were pooled. The area under the curve value for IMA for the diagnosis of ACS was 0.75, and the pooled diagnostic odds ratio value was 3.72. Furthermore, ACS patients with unstable angina had greater serum IMA levels than those with non-ischemic chest pain. In contrast to prior meta-analyses, our findings suggest that determining whether serum IMA levels are effective for diagnosing ACS in the emergency department is difficult. However, the accuracy of these findings cannot be ascertained due to high heterogeneity between studies.

Efficacy of Quantitative Pupillary Light Reflex for Predicting Neurological Outcomes in Patients Treated with Targeted Temperature Management after Cardiac Arrest: A Systematic Review and Meta-Analysis.

Background and objectives: This study aims to evaluate the usefulness of the quantitative pupillary light reflex as a prognostic tool for neurological outcomes in post-cardiac arrest patients treated with targeted temperature management (TTM). Material and Methods: We systematically searched MEDLINE, EMBASE, and the Cochrane Library (search date: 9 July 2021) for studies on post-cardiac arrest patients treated with TTM that had measured the percent constriction of pupillary light reflex (%PLR) with quantitative pupillometry as well as assessed the neurological outcome. For an assessment of the methodological quality of the included studies, two authors utilized the prognosis study tool independently. Results: A total of 618 patients from four studies were included in this study. Standardized mean differences (SMDs) were calculated to compare patients with good or poor neurological outcomes. A higher %PLR measured at 0-24 h after hospital admission was related to good neurological outcomes at 3 months in post-cardiac arrest patients treated with TTM (SMD 0.87; 95% confidence interval 0.70-1.05; I2 = 0%). A higher %PLR amplitude measured at 24-48 h after hospital admission was also associated with a good neurological outcome at 3 months in post-cardiac arrest patients treated with TTM, but with high heterogeneity (standardized mean difference 0.86; 95% confidence interval 0.40-1.32; I2 = 70%). The evidence supporting these findings was of poor quality. For poor neurological outcome, the prognosis accuracy of %PLR was 9.19 (pooled diagnostic odds ratio, I2 = 0%) and 0.75 (area under the curve). Conclusions: The present meta-analysis could not reveal that change of %PLR was an effective tool in predicting neurological outcomes for post-cardiac arrest patients treated with TTM owing to a paucity of included studies and the poor quality of the evidence.

Prognostic Impact of In-Hospital Use of Mechanical Cardiopulmonary Resuscitation Devices Compared with Manual Cardiopulmonary Resuscitation: A Nationwide Population-Based Observational Study in South Korea.

Background and Objectives: This study analyzed the prognostic impact of mechanical cardiopulmonary resuscitation (CPR) devices in out-of-hospital cardiac arrest (OHCA) patients, in comparison to manual CPR. Materials and Methods: This study was a nationwide population-based observational study in South Korea. Data were retrospectively collected from 142,905 OHCA patients using the South Korean Out-of-Hospital Cardiac Arrest Surveillance database. We included adult OHCA patients who received manual or mechanical CPR in the emergency room. The primary outcome was survival at discharge and the secondary outcome was sustained return of spontaneous circulation (ROSC). Statistical analysis included propensity score matching and multivariate logistic regression. Results: A total of 19,045 manual CPR and 1125 mechanical CPR cases (671 AutoPulseTM vs. 305 ThumperTM vs. 149 LUCASTM) were included. In the matched multivariate analyses, all mechanical CPR devices were associated with a lower ROSC than that of manual CPR. AutoPulseTM was associated with lower survival in the multivariate analysis after matching (aOR with 95% CI: 0.57 (0.33-0.96)), but the other mechanical CPR devices were associated with similar survival to discharge as that of manual CPR. Witnessed arrest was commonly associated with high ROSC, but the use of mechanical CPR devices and cardiac origin arrest were associated with low ROSC. Only target temperature management was the common predictor for high survival. Conclusions: The mechanical CPR devices largely led to similar survival to discharge as that of manual CPR in OHCA patients; however, the in-hospital use of the AutoPulseTM device for mechanical CPR may significantly lower survival compared to manual CPR.

Efficacy and safety of erythropoietin in patients with traumatic brain injury: A systematic review and meta-analysis.

OBJECTIVE: The purpose of this study was to evaluate the effects of erythropoietin (EPO) on mortality and neurological outcomes in patients with traumatic brain injury (TBI). MATERIALS AND METHODS: Electronic databases of studies published up to January 5, 2017 were searched to retrieve relevant investigations comparing the outcomes of EPO-treated patients and untreated patients following TBI. We calculated the relative risk (RR) of mortality, neurologic outcomes, and deep vein thrombosis (DVT) with corresponding 95% confidence interval (CI) using meta-analysis. RESULTS: Six randomized controlled clinical trials met the eligibility criteria. In total, 1041 patients were included among the studies. EPO was found to significantly reduce the occurrence of mortality (RR 0.68 [95% CI 0.50-0.95]; P = 0.02), but did not significantly reduce poor functional outcome (RR 1.22 [95% CI 0.82-1.81]; P = 0.33). There were no significant differences in the occurrence of complications, such as DVT, between the treatment groups (RR -0.02 [95% CI -0.06-0.02]; P = 0.81). CONCLUSIONS: Results of the present meta-analysis suggest that the use of EPO may prevent death following TBI without causing adverse events, such as deep vein thrombosis. However, the role of EPO in improving neurological outcome(s) remains unclear. Further well-designed, randomized controlled trials using modified protocols and involving specific patient populations are required to clarify this issue, and to verify the findings.

Zinc Inhibits Expression of Androgen Receptor to Suppress Growth of Prostate Cancer Cells.

The prostate gland contains a high level of intracellular zinc, which is dramatically diminished during prostate cancer (PCa) development. Owing to the unclear role of zinc in this process, therapeutic applications using zinc are limited. This study aimed to clarify the role of zinc and its underlying mechanism in the growth of PCa. ZnCl2 suppressed the proliferation of androgen receptor (AR)-retaining PCa cells, whereas it did not affect AR-deficient PCa cells. In LNCaP and TRAMP-C2 cells, zinc downregulated the expression of AR in a dose- and time-dependent fashion. Zinc-mediated AR suppression accordingly inhibited the androgen-mediated transactivation and expression of the androgen target, prostate specific antigen (PSA). This phenomenon resulted from facilitated protein degradation, not transcriptional control. In studies using mice bearing TRAMP-C2 subcutaneous tumors, the intraperitoneal injection of zinc significantly reduced tumor size. Analyses of both xenograft tumors and normal prostates showed reduced expression of AR and increased cell death. Considering the significant loss of intracellular zinc and the dominant growth-modulating role of AR during PCa development, loss of zinc may be a critical step in the transformation of normal cells to cancer cells. This study provides the underlying mechanism by which zinc functions as a PCa suppressor, and forms the foundation for developing zinc-mediated therapeutics for PCa.

Targeting CD46 Enhances Anti-Tumoral Activity of Adenovirus Type 5 for Bladder Cancer.

CD46 is generally overexpressed in many human cancers, representing a prime target for CD46-binding adenoviruses (Ads). This could help to overcome low anti-tumoral activity by coxsackie-adenoviral receptor (CAR)-targeting cancer gene therapy viruses. However, because of scarce side-by-side information about CAR and CD46 expression levels in cancer cells, mixed observations of cancer therapeutic efficacy have been observed. This study evaluated Ad-mediated therapeutic efficacy using either CAR-targeting Ad5 or CD46-targeting Ad5/35 fiber chimera in bladder cancer cell lines. Compared with normal urothelia, bladder cancer tissue generally overexpressed both CAR and CD46. While CAR expression was not correlated with disease progression, CD46 expression was inversely correlated with tumor grade, stage, and risk grade. In bladder cancer cell lines, expression levels of CD46 and CAR were highly correlated with Ad5/35- and Ad5-mediated gene transduction and cytotoxicity, respectively. In a human EJ bladder cancer xenograft mouse model, with either overexpressed or suppressed CD46 expression levels, Ad5/35-tk followed by ganciclovir (GCV) treatment significantly affected tumor growth, whereas Ad5-tk/GCV had only minimal effects. Overall, our findings suggest that bladder cancer cells overexpress both CAR and CD46, and that adenoviral cancer gene therapy targeting CD46 represents a more suitable therapy option than a CAR-targeting therapy, especially in patients with low risk bladder cancers.

Dose-related effect of statins in patients with endovascular coiling or microsurgical clipping for aneurysmal subarachnoid hemorrhage: updated study-level meta-analysis.

PURPOSE: We aimed to quantitatively assess the effects of short-term statin use on delayed ischemic neurologic deficits (DINDs) and clinical outcomes in patients with aneurysmal subarachnoid hemorrhage (SAH) through a meta-analysis of the available evidence. METHODS: We searched the electronic databases up to April 8, 2016 to retrieve relevant studies comparing the outcomes between immediate statin-treated in statin-naïve patients and untreated patients following aneurysmal SAH. Meta-analysis was performed using Review Manager 5.3. RESULTS: Eight randomized controlled clinical trials (RCTs) and 5 observational studies involving 2148 patients met the eligibility criteria. In the RCTs, statins were found to significantly reduce the occurrence of DINDs (relative risk (RR), 0.76; 95% confidence interval (CI), 0.61-0.94; P = 0.01), but did not significantly reduce poor functional outcomes (RR, 1.01; 95% CI, 0.87-1.16; P = 0.93) or mortality (RR, 0.80; 95% CI, 0.58-1.11; P = 0.18). In observational studies, statin use was not associated with any reduction in DINDs, poor outcome, or mortality. Meta-analysis of RCTs indicated a significant reduction in DINDs and mortality in patients with high-dose statin use (RR, 0.63; 95% CI, 0.42-0.95; P = 0.03; I 2 = 0%; and RR, 0.36; 95% CI, 0.15-0.86; P = 0.02; I 2 = 0%, respectively). CONCLUSION: The present meta-analysis suggests that statin use may prevent DINDs in patients with aneurysmal SAH. Based on our findings, the role of statins in improving neurological outcome was limited. However, the risk of DINDs and mortality decreased with higher statin doses in a dose-dependent manner. Hence, further well-designed RCTs with modified protocols in specific patients are required.

Prognostic role of copeptin after traumatic brain injury: A systematic review and meta-analysis of observational studies.

PURPOSE: Copeptin, the C-terminal portion of provasopressin, has emerged as a novel prognostic marker in neurocritical care, such as in traumatic brain injury (TBI). The aim of this study was to quantitatively assess the prognostic significance of initial plasma copeptin levels in the neurological outcome and mortality after traumatic brain injury. MATERIALS AND METHODS: Six relevant studies with data from 552 patients were included in this meta-analysis. RESULTS: The plasma copeptin levels were found to be significantly higher in patients who died than in the survivors (standardized mean difference [SMD], 1.80). In the four studies reporting Glasgow outcome scale (GOS) data, patients with unfavorable outcomes had significantly higher copeptin levels than those with favorable outcomes (SMD, 1.62). The plasma copeptin level predicted mortality and unfavorable outcomes (AUC, 0.873; AUC, 0.876). CONCLUSIONS: The present meta-analysis suggests that early measurement of plasma copeptin levels can provide better prognostic information about the functional outcome and mortality in patients with TBI.

The effect of peer-group size on the delivery of feedback in basic life support refresher training: a cluster randomized controlled trial.

BACKGROUND: Students are largely providing feedback to one another when instructor facilitates peer feedback rather than teaching in group training. The number of students in a group affect the learning of students in the group training. We aimed to investigate whether a larger group size increases students' test scores on a post-training test with peer feedback facilitated by instructor after video-guided basic life support (BLS) refresher training. Students' one-rescuer adult BLS skills were assessed by a 2-min checklist-based test 1 year after the initial training. METHODS: A cluster randomized controlled trial was conducted to evaluate the effect of student number in a group on BLS refresher training. Participants included 115 final-year medical students undergoing their emergency medicine clerkship. The median number of students was 8 in the large groups and 4 in the standard group. The primary outcome was to examine group differences in post-training test scores after video-guided BLS training. Secondary outcomes included the feedback time, number of feedback topics, and results of end-of-training evaluation questionnaires. RESULTS: Scores on the post-training test increased over three consecutive tests with instructor-led peer feedback, but not differ between large and standard groups. The feedback time was longer and number of feedback topics generated by students were higher in standard groups compared to large groups on the first and second tests. The end-of-training questionnaire revealed that the students in large groups preferred the smaller group size compared to their actual group size. CONCLUSIONS: In this BLS refresher training, the instructor-led group feedback increased the test score after tutorial video-guided BLS learning, irrespective of the group size. A smaller group size allowed more participations in peer feedback.

Dual Gate Black Phosphorus Field Effect Transistors on Glass for NOR Logic and Organic Light Emitting Diode Switching.

We have fabricated dual gate field effect transistors (FETs) with 12 nm-thin black phosphorus (BP) channel on glass substrate, where our BP FETs have a patterned-gate architecture with 30 nm-thick Al2O3 dielectrics on top and bottom of a BP channel. Top gate dielectric has simultaneously been used as device encapsulation layer, controlling the threshold voltage of FETs as well when FETs mainly operate under bottom gate bias. Bottom, top, and dual gate-controlling mobilities were estimated to be 277, 92, and 213 cm(2)/V s, respectively. Maximum ON-current was measured to be ∼5 µA at a drain voltage of -0.1 V but to be as high as ∼50 µA at -1 V, while ON/OFF current ratio appeared to be 3.6 × 10(3) V. As a result, our dual gate BP FETs demonstrate organic light emitting diode (OLED) switching for green and blue OLEDs, also demonstrating NOR logic functions by separately using top- and bottom-input.

An application of the learning curve-cumulative summation test to evaluate training for endotracheal intubation in emergency medicine.

OBJECTIVE: The learning curve-cumulative summation (LC-CUSUM) test allows for quantitative and individual assessments of the learning process. In this study, we evaluated the process of skill acquisition for performing endotracheal intubation (ETI) in three emergency medicine (EM) residents over a 2 year period in their first 2 years of their EM residency. METHODS: We evaluated 342 ETI cases performed by three EM residents using the LC-CUSUM test according to their rate of success or failure of ETI. A 90% success rate (SR) was chosen to define adequate performance and an SR of 80% was considered inadequate. After the learning phase, the standard CUSUM test was applied to ensure that performance was maintained. RESULTS: The mean number of ETI cases required to reach the predefined level of performance was 74.7 (95% CI 62.0 to 87.3). CUSUM tests confirmed that performance was maintained after the learning phase. CONCLUSIONS: By using the LC-CUSUM test, we were able to quantitatively monitor the acquisition of the skill of ETI by EM residents. The LC-CUSUM could be useful for monitoring the learning process for the training of airway management in the practice of EM.

Pathogenic role of HIF-1α in prostate hyperplasia in the presence of chronic inflammation.

Benign prostatic hyperplasia (BPH) commonly occurs in older men with chronic prostatitis. Although BPH is frequently accompanied by inflammation, it is unclear whether inflammation underlies prostate enlargement. Recently, we reported that hypoxia-inducible factor 1α (HIF-1α), which is known to be induced by proinflammatory cytokines, is involved in testosterone-induced prostate hyperplasia. Therefore, we hypothesized that cytokines secreted from infiltrated macrophages under inflammatory conditions stimulate prostate enlargement by up-regulating HIF-1α. In the present study, we injected lipopolysaccharide (LPS) into rat prostates to mimic prostatitis and evaluated prostate hyperplasia 14days later. Epithelial cells of LPS-treated prostates were found to be highly proliferative and HIF-1α levels in prostate tissues to be elevated. When prostate epithelial cells were incubated in conditioned medium from macrophages activated with LPS, they robustly expressed HIF-1α, and under these conditions IL-1ß, IL-6, and TNF-α cytokines were found to mediate HIF-1α induction. In addition, HIF-1α was found to enhance the expression of Twist, which initiates epithelial-mesenchymal transition (EMT). Furthermore, profound EMT features were observed in LPS-treated rat prostates, and the natural HIF-1α inhibitors ascorbate and curcumin were found to attenuate EMT and prostate hyperplasia both in vivo and in vitro. Based on these results, we propose that HIF-1α mediates prostate enlargement under inflammatory conditions, and we suggest that HIF-1α be viewed as a promising target for blocking the transition from prostatitis to BPH.

Ginsenoside Rg3 inhibits lipopolysaccharide-induced adhesion molecule expression in human umbilical vein endothelial cell and C57BL/6 mice.

Intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), P- and E-selectin play a key role for initiation of vascular inflammation. Ginsenoside, a class of steroid glycosides, is abundant in Panax ginseng root, which has been used for health promotion in Korea. In this study, we investigated the mechanism by which ginsenoside Rg3 may inhibit ICAM-1 and VCAM-1 expressions stimulated with lipopolysaccharide (LPS) in human umbilical vein endothelial cell (HUVEC) and C57BL/6 mice. LPS increased ICAM-1 and VCAM-1 expression. Ginsenoside Rg3 prevented LPS-mediated increase of ICAM-1 and VCAM-1 expression. LPS induced IkappaBα (IκBα) degradation within 1 hr. Ginsenoside Rg3 prevented the IκBα degradation stimulated with LPS. Moreover, ginsenoside Rg3 reduced LPS-mediated THP-1 monocyte adhesion to HUVEC, in a concentration-dependent manner. In C57BL/6 mice, injection of LPS increased aortic ICAM-1 and VCAM-1 expression, which was prevented by ginsenoside Rg3. These data provide a novel mechanism where the ginsenoside Rg3 may provide direct vascular benefits with inhibition of leukocyte adhesion into vascular wall thereby providing prevention against vascular inflammatory disease.

The application of flipped learning to a gross anatomy dissection course.

We implemented flipped learning for a gross anatomy dissection course and compared its effects on students' motivation and academic achievement with those of traditional dissection methods. We invited 142 first-year medical students at Chonnam National University Medical School to participate in this study. All participants engaged in traditional dissection methods in the first part of the study and flipped learning in the latter part. Medical students' motivation to learn anatomy by cadaveric dissection was measured using the ARCS (Attention, Relevance, Confidence, and Satisfaction) model. Thereafter, all students completed a written examination consisting of 96 multiple-choice questions. The students' mean motivational score regarding attention was significantly higher in association with flipped learning than with traditional learning. However, the students' mean motivational scores regarding relevance, confidence, and satisfaction were not significantly different between the methods. Additionally, the mean anatomy practice test score was significantly higher in association with flipped learning than with traditional learning. The students' motivational scores and anatomy practice test scores associated with flipped learning positively correlated with the extent of learning material completion. The students' responses indicated that flipped learning helped enhance the learning process, improve time management, reduce confusion during practice, and promote independent practice. The application of flipped learning to a cadaveric dissection course increased individual learning motivation, which improved learning activities both in and out of class, as well as academic achievement.

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.