Relationship between the muscle relaxation effect and body muscle mass measured using bioelectrical impedance analysis: A nonrandomized controlled trial

Relationship between muscle mass ratio and rocuronium dose required for maintaining deep neuromuscular blockade: A prospective observational study

BACKGROUND

Deep neuromuscular blockade (NMB) has benefits in various surgical procedures, however, precise quantitative neuromuscular monitoring is crucial for its proper maintenance and recovery. Neuromuscular blocking agent dosage relies on actual body weight (ABW), but this varies among individuals. Therefore, this study hypothesizes that there is a correlation between the rocuronium requirement for deep NMB and muscle mass ratio measured by bioelectric impedance analysis.

METHODS

Ninety adult female patients undergoing laparoscopic operation were enrolled in this study. Muscle and fat masses were assessed using a body composition analyser. Deep NMB, defined as a post-tetanic count of 1-2, was maintained through the continuous infusion of rocuronium. The primary outcome involves determining the correlation between the rocuronium dose required for deep NMB and the muscle mass ratio. Conversely, secondary outcomes included assessing the relationship between the rocuronium dose for deep NMB and fat mass ratio, and ABW. Additionally, we investigated their relationship with rocuronium onset time and profound blockade duration.

RESULTS

No relationship was observed between the muscle mass ratio and rocuronium dose required for maintaining deep NMB (r = 0.059 [95% CI = 0.153-0.267], p = 0.586). Fat mass ratio and ABW showed no correlation with the rocuronium dose, whereas rocuronium onset time was positively correlated with muscle mass ratio (r = 0.327) and negatively correlated with fat mass ratio (r = -0.302), respectively. Profound blockade duration showed no correlation with any of the assessed variables.

CONCLUSIONS

No correlation was detected between muscle mass ratio and the rocuronium dose required to achieve deep NMB.

Influence of the amount of skeletal muscle mass on rocuronium-induced neuromuscular block

OBJECTIVE

To evaluate the effects of skeletal muscle mass on the rocuronium-induced neuromuscular block.

DESIGN

A prospective, double-blinded, observational study SETTING: A tertiary care university hospital POPULATION: One hundred one patients aged 18-65 years who were scheduled to undergo major surgery lasting more than 1 h under general anaesthesia.

METHODS

All participants underwent body composition analysis before anaesthesia and were allocated into two groups; the muscular and non-muscular group, according to skeletal muscle mass. During anaesthesia induction, rocuronium 1.0 mg kg^-1 of total body weight was injected followed by neuromuscular monitoring using train-of-four stimulation every 15 s.

MAIN OUTCOME MEASURES

The onset time of rocuronium included the elapsed time from the rocuronium injection until 95% depression of first twitch (T1) and the time to no response to TOF stimulation. The duration was evaluated as the elapsed time from the rocuronium injection to 25% recovery of the final T1 (T_DUR25), and the time to the reappearance of T1 (T_TOF1) and T4 (T_TOF4). These pharmacologic data were compared between two groups.

RESULTS

There was no significant difference in the onset time of rocuronium between the two groups. However, T_DUR25 (min) was significantly shorter in the muscular group than in the non-muscular group (p =  0.035 and p =  0.014 in males and females, respectively). T_TOF1 and T_TOF4 were also shorter in the muscular group than in the non-muscular group.

CONCLUSIONS

Total body weight-based dosing of rocuronium might prolong the neuromuscular relaxation effect in patients with a small amount of skeletal muscle.

The impact of poor dental status and removable dental prosthesis quality on body composition, masticatory performance and oral health-related quality of life: a cross-sectional study in older adults

Background

To determine the impact of dental status, types, and quality of dental prostheses on body composition, masticatory performance and oral health-related quality of life (OHRQoL). Potential associations between body composition, masticatory performance and OHRQoL were also investigated.

Methods

This cross-sectional study included 110 older adults who received prosthodontic treatment at the Dental Faculty Clinics at Chulalongkorn University. Participants were categorized according to their dental prostheses: complete denture (CD), removable partial denture (RPD) and fixed partial denture (FPD). Retention and stability of the RPD and CD were evaluated using the CU-modified Kapur and the modified NHANES III criteria to classify denture quality into acceptable and unacceptable. Dental status including posterior occluding pairs and number of remaining natural teeth were assessed intraorally. Dependent variables were body composition, masticatory performance and OHRQoL. Body composition, including muscle mass (kg), bone mass (kg), basal metabolic rate (kcal) and visceral fat (%) were determined through a bioelectrical impedance analysis. Masticatory performance was assessed using a multiple sieve method of peanut mastication. OHRQoL was assessed using the validated Thai version of Oral Impacts on Daily Performances (Thai-OIDP) index. After adjusting for covariates, including age and sex, the associations between oral and dental prosthesis status and body composition, masticatory performance as well as OIDP score were analyzed using multivariable linear and negative binomial regression analyses. Spearman’s correlation was used to determine the potential associations between body composition, masticatory performance and OHRQoL.

Results

The presence of fewer natural teeth or wearing an unacceptable removable denture were factors associated with lower bone mass, muscle mass and basal metabolic rate, and with a higher visceral fat. Similar dental and removable denture status were also associated with larger peanut particle size and higher OIDP score. Masticatory performance and OHRQoL variables were moderately correlated (Spearman's rho = 0.44). However, body composition was not correlated with masticatory performance or OHRQoL.

Conclusions

In individuals wearing dental prostheses, factors such as severity of tooth loss, types, and quality of dental prostheses, particularly retention and stability, negatively impacted not only masticatory function and OHRQoL, but also their overall body composition and health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02103-7.