Adductor Pollicis Research Articles

Comparison of measurements obtained with TOF-Cuff placed on the arm and the TOF-Scan on the adductor pollicis muscle during general anaesthesia using mivacurium: a prospective observational clinical trial

Adequate neuromuscular monitoring of patients is essential to verify complete recovery of neuromuscular function before tracheal extubation. This study aimed to assess the correlation between the values acquired from the brachialis muscle using TOF-Cuff and those obtained from the adductor pollicis muscle with TOF-Scan during anaesthesia with mivacurium. Twenty-five patients were enrolled in the observational clinical trial, with the TOF-Cuff positioned on the upper arm and the TOF-Scan on the thumb. Train-of-four (TOF) values were simultaneously recorded by both devices at 30-second intervals before intubation. Subsequently, measurements were taken every 5 min until the removal of the endotracheal tube. Bland-Altman analyses were conducted to compare assessed endpoints obtained by using the TOF-Cuff and the TOF-Scan. The median onset time measured with TOF-Cuff was numerically longer compared to the TOF-Scan score (120 s vs. 90 s, P = 0.42). Spearman rank correlation revealed a significant positive correlation between onset times measured by TOF-Cuff and TOF-Scan (R = 0.73, P = 0.0001, 95% CI 0.446 to 0.875). For the time to recovery assessed with both methods, Spearman correlation coefficient was R = 0.35 and did not reach statistical significance (P = 0.1). Multiplying the time to recovery from the last dose (according to TOF-Scan) by 0.43 to 2.66, provided concordance with the TOF-Cuff result for the entire range of study group. Conclusion. The concordance between the TOF-Scan on the adductor pollicis and the TOF-Cuff on the upper limb was found to be good. However, both devices showed a false-negative result in patients with clinical symptoms of preterm recovery.

Train-of-four ratio, counts and post tetanic counts with the Tetragraph electromyograph in comparison to mechanomyography.

Automated EMG devices to detect compound muscle action potentials from the adductor pollicis muscle in response to ulnar nerve stimulation, regardless of hand and thumb position, may serve as a better reference ("gold standard") for clinical assessment of neuromuscular function than traditional mechanomyography (MMG) systems that need custom design and validation in lab settings. This evaluation compared the TetraGraph EMG system against a validated MMG device to investigate the accuracy and repeatability of this quantitative EMG monitor for detecting onset, offset and deep neuromuscular block. Simultaneous muscle action potential recordings from the EMG neuromuscular monitor and muscle contractions from an in-house developed MMG monitor in response to ulnar nerve stimulation were obtained from patients having elective surgery requiring neuromuscular block. Train-of-four (TOF) ratios, TOF counts, and post-tetanic counts (PTCs) were recorded simultaneously from the same hand muscle and compared. In total, 685 pairs of simultaneous TOF ratios were evaluated. The mean difference (bias) of TOF ratios between devices was small (-2.1%). TOF counts from 285 data pairs were within a count of 2 or less 96% of the time. During deep block, PTC comparisons from 215 data pairs were within a count of 2 or less 95% of the time. These findings, along with prior EMG device evaluations, indicate that real-time EMG neuromuscular monitoring technology to detect muscle action potentials from the adductor pollicis in the clinical setting is closely aligned with the force of thumb contraction determined from MMG. The accuracy of quantitative EMG technology of the TetraGraph EMG system lends strong support for this monitor, along with other similarly validated EMG monitors, to become a clinical standard for all phases (onset, depth and reversal) of neuromuscular block in clinical practice.

Evaluation of Neuromuscular Blockade: A Comparative Study of TOF-Cuff® on the Lower Leg and TOF-Scan® on the Ulnar Nerve During Mivacurium Anesthesia.

BACKGROUND To evaluate neuromuscular monitoring during anesthesia with mivacurium, this study assessed the correlation between measurements of TOF-Cuff® placed on the lower leg and stimulating the tibial nerve and TOF-Scan® values from the adductor pollicis muscle. Additionally, systolic (SBP) and diastolic (DBO) blood pressure measured in both locations were compared. MATERIAL AND METHODS Twenty-six patients participated in this observational clinical trial. The TOF-Cuff® was placed on the lower leg and the TOF-Scan® was placed on the thumb. Train-of-four (TOF) values were recorded simultaneously by both devices at 30-second intervals before intubation. Measurements continued every 5 minutes until extubation. Bland-Altman analyses compared TOF values obtained from the 2 devices. RESULTS Time to onset and relaxation time did not differ significantly; the number of patients presenting a lack of blockade despite TOF=0 was also concordant. The time from the last dose of mivacurium to TOF ratio >90 was shorter on the leg than on hand (median 20 [5-28, 0-65] min vs 30 [20-35, 0-60] min, p=0.025). The median (range, interquartile range) difference between measurements was: 11.6 (-41 to 45, 2-19) for SBP and -8 (-28 to 26, -15 to -4) for DBP at baseline (p=0.0495); 5 (-53 to 55, -2 to 9) for SBP and -11 (-45 to 29, -19 to -5) (p=0.0017) for DBP during the blockade. CONCLUSIONS Time-to-onset and SBP are comparable between these 2 methods, in contrast to time-to-recovery and diastolic blood pressure, and this should be considered in case of the inability to apply the TOF-Cuff on the leg.

Effects of ischemic pre-conditioning on electrically stimulated contractions.

Ischemic pre-conditioning (IPC) offers protection against future ischemic events and may improve sports performance due to several mechanisms at local and systemic levels. This study investigates the local effects on muscle contractility in electrically induced muscle contractions, thus effectively excluding any uncontrolled change in the motor drive. Twenty-one subjects were divided into two groups: 12 subjects in the IPC group (3 × 5/5min right arm ischemia/reperfusion; cuff pressure 250mmHg) and 9 subjects in the SHAM group (same treatment at 20mmHg). The adductor pollicis was contracted by supramaximal stimulation of the ulnar nerve with single pulses, trains of stimuli (5, 8, 10 and 12Hz, 1-s duration) and bursts (4 pulses, 25Hz), all separated by 5-s intervals. The stimulation sequence was delivered before and 15 and 30min after IPC/SHAM treatment. The isometric contraction force, the superficial electromyographic signal, and tissue oxygenation were continuously monitored. A significant force decrease in time was observed at 8, 10 (p < 0.01) and 12Hz (p < 0.05) along with a decrease in half-relaxation time in single twitches and bursts (p = 0.01), regardless of treatment. This general time-related weakening was more marked in IPC than SHAM at 5-Hz stimulation. No effects were observed on the magnitude of the superficial electromyographic signal. Data indicate that IPC does not increase muscle force during electrically stimulated contractions, supporting the idea that IPC's ergogenic effects are not due to increased muscle contractility.

Testing the predictive capacity of a muscle fatigue model on electrically stimulated adductor pollicis.

Based on the critical power (Pc or critical force; Fc) concept, a recent mathematical model formalised the proportional link between the decrease in maximal capacities during fatiguing exercises and the amount of impulse accumulated above Fc. This study aimed to provide experimental support to this mathematical model of muscle fatigability in the severe domain through testing (i) the model identifiability using non-exhausting tests and (ii) the model ability to predict time to exhaustion (tlim)and maximal force (Fmax)decrease. The model was tested on eight participants using electrically stimulated adductor pollicis muscle force. The Fmax was recorded every 15s for all tests, including five constant tests to estimate the initial maximal force (Fi), Fc, and a time constant (τ). The model's parameters were used to compare the predicted and observed tlim values of the incremental ramp test and Fmax(t) of the sine test. The results showed that the model accurately estimated Fi, Fc, and τ (CI95% = 2.7%Fi and 9.1s for Fc and τ, respectively; median adjusted r2 = 0.96) and predicted tlim and Fmax with low systematic and random errors (11 ± 20% and -1.8 ± 7.7%Fi, respectively). This study revealed the potential applications of a novel mathematical formalisation that encompasses previous research on the critical power concept. The results indicated that the model's parameters can be determined from non-exhaustive tests, as long as maximal capacities are regularly assessed. With these parameters, the evolution of maximal capacities (i.e. fatigability) at any point during a known exercise and the time to exhaustion can be accurately predicted.

Phase Angle but Not Psoas Muscle Predicts Nutritional Risk and Prognosis in Males with Hepatocellular Carcinoma

Despite those with hepatocellular carcinoma (HCC) being at increased risk of malnutrition, there is a notable absence of practical approaches for nutritional assessment in clinical practice. We investigated the usefulness of phase angle (PhA) and Total Psoas Area Index (TPAI) for indicating nutritional risk and HCC prognosis. Weight, height, body mass index (BMI), adductor pollicis muscle thickness (APMT), and handgrip strength (HGS) were assessed. The Nutritional Risk Index (NRI) was calculated. Body composition was assessed using bioimpedance spectroscopy and magnetic resonance imaging. The Child-Turcotte-Pugh (CTP) score and Barcelona-Clinic Liver Cancer (BCLC) classification determined the prognosis. Fifty-one males with HCC were enrolled (CTP C = 11.8%). PhA showed a moderate positive correlation with APMT (r = 0.450; p < 0.001) and HGS (r = 0.418; p = 0.002) and a weak positive correlation with TPAI (r = 0.332; p = 0.021). PhA had a strong positive correlation with NRI (r = 0.614; p < 0.001). Mean PhA values were significantly different according to disease severity (CTP C p = 0.001, and BCLC D p = 0.053). TPAI had no significant correlation with HGS, CTP, or BCLC. PhA was a superior approach for predicting nutritional risk and prognosis in HCC than TPAI. Lower PhA is associated with disease progression, lower muscle mass and function, greater severity of nutritional risk, and increased mortality in HCC.

Comparative clinical study of attenuation of hemodynamic response to laryngoscopy and endotracheal intubation using clinical assessment guidance versus neuromuscular block monitoring guidance

Background: The hemodynamic response to the stress of laryngoscopy and endotracheal intubation does not present a problem for most patients, except in cardiovascular or cerebral disease. Various anesthetic techniques and drugs are available to control the hemodynamic response to laryngoscopy and intubation. However administration of an additional drug may adversely affect hemodynamics of the patient or unnecessarily increase the depth of anesthesia. Hence a non pharmacological measure to reduce response is preferred. The purpose of this study was to compare the hemodynamic response during laryngoscopy and intubation when choice of the moment of intubation is directed by either clinical assessment and neuromuscular monitoring with train of four. Methods: A total of 60 patients were randomised into two groups. In Group M endotracheal intubation was done after train of four count became zero in adductor pollicis muscle. In Group C timing of intubation was determined clinically by assessment of jaw muscle relaxation. Changes in heart rate (HR), systolic BP (SBP), diasolic BP (DBP), mean arterial pressure (MAP), time between the administration of neuromuscular blocking agent and endotracheal intubation was recorded. Results were analysed by the analysis of variance and chi square test. Results: Heart rate, SBP, DBP and mean arterial pressure were significantly higher in Group C as compared to Group M after laryngoscopy and endotracheal intubation (P&lt;0.05). The mean time required for onset of intubation was significantly shorter in Group C compared to Group M. Conclusion: The objective assessment of neuromuscular relaxation prior to endotracheal intubation provides better attenuation of hemodynamic responses. Keywords: hemodynamic response; laryngoscopy; endotracheal intubation; neuromuscular block

Pediatric Intraoperative Electromyographic Responses at the Adductor Pollicis and Flexor Hallucis Brevis Muscles: A Prospective, Comparative Analysis.

Peripheral nerve stimulation with a train-of-four (TOF) pattern can be used intraoperatively to evaluate the depth of neuromuscular block and confirm recovery from neuromuscular blocking agents (NMBAs). Quantitative monitoring can be challenging in infants and children due to patient size, equipment technology, and limited access to monitoring sites. Although the adductor pollicis muscle is the preferred site of monitoring, the foot is an alternative when the hands are unavailable. However, there is little information on comparative evoked neuromuscular responses at those 2 sites. Pediatric patients undergoing inpatient surgery requiring NMBA administration were studied after informed consent. Electromyographic (EMG) monitoring was performed simultaneously in each participant at the hand (ulnar nerve, adductor pollicis muscle) and the foot (posterior tibial nerve, flexor hallucis brevis muscle). Fifty patients with a mean age of 3.0 ± standard deviation (SD) 2.9 years were studied. The baseline first twitch amplitude (T1) of TOF at the foot (12.46 mV) was 4.47 mV higher than at the hand (P <.0001). The baseline TOF ratio (TOFR) before NMBA administration and the maximum TOFR after antagonism with sugammadex were not different at the 2 sites. The onset time until the T1 decreased to 10% or 5% of the baseline value (T1) was delayed by approximately 90 seconds (both P =.014) at the foot compared with the hand. The TOFR at the foot recovered (TOFR ≥0.9) 191 seconds later than when this threshold was achieved at the hand (P =.017). After antagonism, T1 did not return to its baseline value, a typical finding with EMG monitoring, but the fractional recovery (maximum T1 at recovery divided by the baseline T1) at the hand and foot was not different, 0.81 and 0.77, respectively (P =.68). The final TOFR achieved at recovery was approximately 100% and was not different between the 2 sites. Although this study in young children demonstrated the feasibility of TOF monitoring, interpretation of the depth of neuromuscular block needs to consider the delayed onset and the delayed recovery of TOFR at the foot compared to the hand. The delay in achieving these end points when monitoring the foot may impact the timing of tracheal intubation and assessment of adequate recovery of neuromuscular block to allow tracheal extubation (ie, TOFR ≥0.9).

Assessing the peripheral effect of ischemic preconditioning using electrically-stimulated contraction of the adductor pollicis

Assessing the peripheral effect of ischemic preconditioning using electrically-stimulated contraction of the adductor pollicis

The Effect of Phonomyography Prototype for Intraoperative Neuromuscular Monitoring: A Preliminary Study.

Quantitative neuromuscular monitoring, as extolled by clinical guidelines, is advocated to circumvent the complications associated with neuromuscular blockers (NMBs), such as residual neuromuscular block (rNMB). Nonetheless, the worldwide utilization of such methods remains undesirable. Phonomyography (PMG) boasts the advantages of convenience, stability, and multi-muscle recording which may be a promising monitoring method. The purpose of this preliminary study is conducting a feasibility analysis and an effectiveness evaluation of a PMG prototype under general anesthesia. A prospective observational preliminary study was conducted. Twenty-five adults who had undergone none-cardiac elective surgery were enrolled. The PMG prototype and TOF-Watch SX simultaneously recorded the pharmacodynamic properties of single bolus rocuronium at the ipsilateral adductor pollicis for each patient. For the primary outcome, the time duration to 0.9 TOF ratio of the two devices reached no statistical significance (p > 0.05). For secondary outcomes, the multi-temporal neuromuscular-monitoring measurements between the two devices also reached no statistical significance (p > 0.05). What is more, both the Spearman's and Pearson's correlation tests revealed a strong correlation across all monitoring periods between the PMG prototype and TOF-Watch SX. Additionally, Bland-Altman plots demonstrated a good agreement between the two devices. Thus, the PMG prototype was a feasible, secure, and effective neuromuscular-monitoring technique during general anesthesia and was interchangeable with TOF-Watch SX.

Predictive value of adductor pollicis muscle thickness for ultrasound-based sarcopenia in older adults.

The adductor pollicis muscle thickness (APMT) is least affected by subcutaneous adipose tissue and can be measured externally. The aim of this study is to identify the predictive value of APMT for the diagnosis of ultrasonography-based sarcopenia. A total of 245 outpatients who were aged ≥65 years (49 with sarcopenia and 196 without sarcopenia) were included in this cross-sectional study. Patients with knee or hip replacement, advanced dementia, cerebrovascular disease, neurodegenerative disease, or decompensated heart failure and those using drugs that affect muscle functions, such as steroids, were excluded. Comprehensive geriatric assessments and anthropometric measurements of the patients were performed. APMT was assessed with a skinfold caliper. The diagnosis of sarcopenia was based on a low Sonographic Thigh Adjustment Ratio (STAR)index (anterior thigh muscle thickness by ultrasonography/body mass index [BMI] ratio, cutoff points are <1.4 for men and <1.0 for women) and low handgrip strength. The predictive ability of APMT for ultrasound-based sarcopenia diagnosis was examined. There was no significant difference in terms of arm and calf circumference and BMI between the sarcopenic and nonsarcopenic groups. APMT, handgrip strength, anterior thigh muscle thickness, and gait speed were significantly lower in the patients with sarcopenia. The best cutoff points of APMT for sarcopenia were ≤16.5 for women and ≤21.5 for men with areas under the curve of 0.70 and 0.66, respectively, and negative predictive values of 91.2 and 94.3, respectively (P < 0.001). APMT can be a useful anthropometric marker for ultrasound-based sarcopenia diagnosis.

Risk of Sarcopenia Identified by Sarc-Calf, Nutritional Status and Hand Grip Strength in Patients with Hematological Cancer.

Background: Hematological cancer patients are prone to the development of sarcopenia and impaired nutritional and functional status. SARC-CalF is a screening tool for the risk of sarcopenia that has shown good results in this population. This study aimed to identify the risk of sarcopenia by SARC-CalF and to verify its association with nutritional status and Hand Grip Strength (HGS) in patients with hematological cancer. Materials and Methods: Adult patients, of both sexes, with hematological cancer, and in outpatient care participated in the study. We measured the Hand Grip Strength of the Dominant Hand (HGSD) and the Adductor Pollicis Muscle Thickness of the Dominant Hand (APMTD). Moreover, we applied the Patient-Generated Subjective Global Assessment (PG-SGA) and SARC-CalF. Data were analyzed with SPSS® software, 22.0, with a significance level of 5.0%. Results: Fifty-one patients aged an average of 60.4 ± 15.1 years were evaluated. Of those, 58.8% were elderly, 51% female, and 80.4% declared themselves non-white. The predominant diagnosis was Mature B Lymphoid Cell Neoplasia (37.7%), and 60.8% of the patients had a diagnosis time of ≤ 3 years. PG-SGA revealed that 35.3% of the patients were malnourished; APMTD and HGSD revealed that 60.8% and 25.5% had reduced muscle strength, respectively. SARC-CalF exposed that 39.2% of the patients were at risk for sarcopenia. Significant associations were found between SARC-CalF and diagnosis time ≤ 3 years (p = 0.039), PG-SGA (p = 0.020), APMTD (p = 0.039) and HGSD (p = 0.002). After binary logistic regression adjusted for age and sex, the reduced HGSD remained associated with the risk of sarcopenia. Conclusion: SARC-CalF identified a risk of sarcopenia in 39.2% of patients. The reduced HGSD was associated with the risk of sarcopenia.

The predictive capacity of adductor pollicis muscle thickness for physical frailty in older adults.

There is a need for an easily measurable and reliable surrogate marker for physical frailty. This study aims to investigate the predictive capacity of adductor pollicis muscle thickness (AMPT), which can be easily measured externally and minimally influenced by subcutaneous adipose tissue, for physical frailty. A total of 589 patients (16.3% physically frail, 54.7% pre-frail, 29% robust) were included. Comprehensive geriatric assessments and anthropometric measurements of the patients were performed. APMT was assessed with a skinfold caliper. Physical frailty was diagnosed using the fried frailty phenotype. The predictive ability of APMT for the diagnosis of frailty was examined. Of all the participants, 64.3% were women, and the average age was 74 ± 5.9years. There was no significant difference in waist and hip circumference, or body mass index between the frail and non-frail groups. APMT, handgrip strength, gait speed, and calf circumference were significantly lower in frail patients than in non-frail ones (p < 0.01). The area under the curve (AUC) of APMT for physical frailty was determined to be 0.627 (95% confidence interval [CI] 0.58-0.66; p < 0.001). The best cut-off value for APMT was ≤ 18.5mm for all individuals. Adductor pollicis muscle thickness can be a useful anthropometric marker for evaluating the risk of physical frailty.

The first and second phases of the muscle compound action potential in the thumb are differently affected by electrical stimulation trains.

Sarcolemmal membrane excitability is often evaluated by considering the peak-to-peak amplitude of the compound muscle action potential (M wave). However, the first and second M-wave phases represent distinct properties of the muscle action potential, which are differentially affected by sarcolemma properties and other factors such as muscle architecture. Contrasting with previous studies in which voluntary contractions have been used to induce muscle fatigue, we used repeated electrically induced tetanic contractions of the adductor pollicis muscle and assessed the kinetics of M-wave properties during the course of the contractions. Eighteen participants (24 ± 6 yr; means ± SD) underwent 30 electrically evoked tetanic contractions delivered at 30 Hz, each lasting 3 s with 1 s intervals. We recorded the amplitudes of the first and second M-wave phases for each stimulation. During the initial stimulation train, the first and second M-wave phases exhibited distinct kinetics. The first phase amplitude showed a rapid decrease to reach ∼59% of its initial value (P < 0.001), whereas the second phase amplitude displayed an initial transient increase of ∼19% (P = 0.007). Within subsequent trains, both the first and second phase amplitudes consistently decreased as fatigue developed with a reduction during the last train reaching ∼47% of its initial value (P < 0.001). Analyzing the first M wave of each stimulation train unveiled different kinetics for the first and second phases during the initial trains, but these distinctions disappeared as fatigue progressed. These findings underscore the interplay of factors affecting the M wave and emphasize the significance of separately scrutinizing its first and second phases when assessing membrane excitability adjustments during muscle contractions.NEW & NOTEWORTHY Our understanding of how the first and second phases of the compound muscle action potential (M wave) behave during fatigue remains incomplete. Using electrically evoked repeated tetanic contractions of the adductor pollicis, we showed that the first and second phases of the M wave followed distinct kinetics only during the early stages of fatigue development. This suggests that the factors affecting the M-wave first and second phases may change as fatigue develops.

ADDUCTOR POLLICIS MUSCLE THICKNESS AS A DIAGNOSTIC TOOL FOR MALNUTRITION IN HOSPITALIZED PATIENTS

Malnutrition causes changes in body composition and compromises the physical and mental functions of individuals. One of its main characteristics is involuntary weight loss, associated with worse health outcomes. In hospital environments, the risk for the condition is high, especially among critical patients, the elderly or those undergoing surgery. This study explores the potential of adductor pollicis muscle thickness (EMAP) as an auxiliary diagnostic tool for detecting malnutrition in hospitalized patients, given its accessibility and low cost. The research involved 100 adult individuals and evaluated the correlations between EMAP, arm circumference (CB) and calf circumference (CP) with the participants body mass index (BMI). Furthermore, it suggested cut-off points for these anthropometric measurements for detecting malnutrition. The results indicated that CB and CP correlated more strongly with BMI compared to EMAP, being more effective choices for nutritional diagnosis. Regarding cutoff points, the values with the highest sensitivity and specificity for diagnosing malnutrition were 12.50 mm for EMAP, 26.00 cm for CB and 30.50 cm for CP, respectively.

Examination of accessory extensor carpi radialis longus and brevis musculotendinous units for functional impact and tendon transfer suitability

IntroductionArchitectural characteristics of skeletal muscles are used to inform biomechanical analysis and candidacy for tendon transfer surgeries. Tendons of non-typical skeletal muscles may serve as optimal grafts, yet a thorough comparison of their parameters to those of typical musculature is not well represented in current literature. This study aims to analyze accessory extensor carpi radialis longus (aECRL) and accessory carpi radialis brevis (aECRB) muscles for their functional impact and suitability for use in tendon transfer surgeries. MethodsOut of 122 dissected forearms examined, one right aECRB and one left aECRL were discovered and photographed in situ. The accessory muscles, along with eleven other muscles associated with ECRL and ECRB tendon transfers from the same forearms, were analyzed for their sarcomere contraction states, structural properties, and maximal isometric force (Fmax) generating capacities. An architectural difference index was then calculated between each muscle to determine and discuss possible candidates for tendon transfer surgeries. ResultsThe Fmax of aECRL, ECRL, aECRB, and ECRB were determined to be 11.78 N, 57.24 N, 28.21 N, and 78.64 N, respectively. In this regard, aECRL and aECRB represented a 20.58% and 35.87% increase to ECRL and ECRB Fmax, respectively. The aECRL inserted with ECRB, and the aECRB inserted with ECRL. The aECRL and aECRB tendons, measuring 188.33 mm × 2.98 mm and 217.17 mm × 3.00 mm respectively, coursed independently with the ECRL and ECRB tendons to their shared insertions. The aECRL and aECRB muscles were each most structurally similar to the extensor pollicis longus and adductor pollicis muscles. ConclusionsBased on their morphology and structural characteristics, the aECRL and aECRB may be suitable grafts in adductorplasty or for extensor pollicis longus muscle/tendon repair. As the aECRL and aECRB tendons were relatively superficial and considerably long and wide, they may also be suitable for other musculotendon-based surgeries elsewhere in the body. This report may contribute new and beneficial insights for healthcare providers and medical educators when presented with cases where upper extremity musculotendinous reconstruction is warranted and/or non-typical musculoskeletal morphologies – particularly aECRL and aECRB – are present.

Association between adductor pollicis muscle thickness and low skeletal muscle mass index in community-dwelling older women undergoing outpatient rehabilitation

ObjectiveThe accuracy of sarcopenia determination using adductor pollicis muscle thickness (APMT) has been reported. However, the relationship between APMT and low skeletal muscle mass index (SMI) is unclear. The purpose of this study is to investigate the relationship between APMT and low SMI and APMT performance to diagnose low SMI in community-dwelling older women undergoing outpatient rehabilitation. MethodsThis study included 65 older women (mean age: 86.4 years). Subjects were received outpatient rehabilitation one to three times a week. The main outcomes were low SMI as determined using the Asian working group for sarcopenia 2019 and APMT. Logistic regression analysis was performed with low SMI as the dependent variable, APMT, and propensity score calculated using age, sex, number of medications, updated Charlson comorbidity index as the independent variable. A receiver operating characteristic (ROC) curve of APMT for low SMI was created. A cut-off value was calculated using the Youden index. ResultsAmong the 65 subjects, 45 (69.2%) had low SMI. The results of the logistic regression analysis showed a significant association between APMT and low SMI (odds ratio: 0.482 {95% confidence interval [CI]: 0.313–0.744}). The cut-off value of APMT calculated from the ROC curve was 13mm. The sensitivity and specificity of this cut-off value were 0.800 (95% CI: 0.654-0.904) (36 out of 45 subjects) and 0.850 (95% CI: 0.621-0.968) (17 out of 20 subjects), respectively. The positive predictive value, negative predictive value, and area under the curve were 0.923 (95% CI: 0.791-0.984), 0.654 (95% CI: 0.443-0.828), and 0.843 (95% CI: 0.731-0.955), respectively. The APMT cut-off value of 13mm is good to identify low SMI. ConclusionsThe results of this study show that APMT is associated with low SMI. Furthermore, the cut-off value of APMT for determining low SMI was 13 mm. The APMT cut-off value of 13mm is good to identify low SMI. Our findings indicate that measuring APMT is useful for determining low SMI in community-dwelling older women undergoing outpatient rehabilitation.

Predictive ability of adductor pollicis muscle thickness on glim criteria based malnutrition

Predictive ability of adductor pollicis muscle thickness on glim criteria based malnutrition

Adductor pollicis muscle thickness as an anthropometric marker of ultrasonography based sarcopenia

Adductor pollicis muscle thickness as an anthropometric marker of ultrasonography based sarcopenia

Validation of a convolutional neural network that reliably identifies electromyographic compound motor action potentials following train-of-four stimulation: an algorithm development experimental study

BackgroundInternational guidelines recommend quantitative neuromuscular monitoring when administering neuromuscular blocking agents. The train-of-four count is important for determining the depth of block and appropriate reversal agents and doses. However, identifying valid compound motor action potentials (cMAPs) during surgery can be challenging because of low-amplitude signals and an inability to observe motor responses. A convolutional neural network (CNN) to classify cMAPs as valid or not might improve the accuracy of such determinations. MethodsWe modified a high-accuracy CNN originally developed to identify handwritten numbers. For training, we used digitised electromyograph waveforms (TetraGraph) from a previous study of 29 patients and tuned the model parameters using leave-one-out cross-validation. External validation used a dataset of 19 patients from another study with the same neuromuscular block monitor but with different patient, surgical, and protocol characteristics. All patients underwent ulnar nerve stimulation at the wrist and the surface electromyogram was recorded from the adductor pollicis muscle. ResultsThe tuned CNN performed highly on the validation dataset, with an accuracy of 0.9997 (99% confidence interval 0.9994–0.9999) and F1 score=0.9998. Performance was equally good for classifying the four individual responses in the train-of-four sequence. The calibration plot showed excellent agreement between the predicted probabilities and the actual prevalence of valid cMAPs. Ten-fold cross-validation using all data showed similar high performance. ConclusionsThe CNN distinguished valid cMAPs from artifacts after ulnar nerve stimulation at the wrist with >99.5% accuracy. Incorporation of such a process within quantitative electromyographic neuromuscular block monitors is feasible.