Current clinical application of dantrolene sodium

Dantrolene sodium (DS) was first introduced as an oral antispasmodic drug. However, in 1975, DS was demonstrated to be effective for managing malignant hyperthermia (MH) and was adopted as the primary therapeutic drug after intravenous administration. However, it is difficult to administer DS intravenously to manage MH. MH is life-threatening, pharmacogenomically related, and induced by depolarizing neuromuscular blocking agents or inhalational anesthetics. All anesthesiologists should know the pharmacology of DS. DS suppresses Ca2+ release from ryanodine receptors (RyRs). RyRs are expressed in various tissues, although their distribution differs among subtypes. The anatomical and physiological functions of RyRs have also been demonstrated as effective therapeutic drugs for cardiac arrhythmias, Alzheimer’s disease, and other RyR-related diseases. Recently, a new formulation was introduced that enhanced the hydrophilicity of the lipophilic DS. The authors summarize the pharmacological properties of DS and comment on its indications, contraindications, adverse effects, and interactions with other drugs by reviewing reference articles

Chronic exposure to dexamethasone may not affect sugammadex reversal of rocuronium-induced neuromuscular blockade: an in vivo study on rats

Background Chronic glucocorticoid exposure is associated with resistance to nondepolarizing neuromuscular blocking agents. Therefore, we hypothesized that sugammadex-induced recovery would occur more rapidly in subjects exposed to chronic dexamethasone compared to those who were not exposed. This study evaluated the sugammadex-induced recovery profile after neuromuscular blockade (NMB) in rats exposed to chronic dexamethasone. Methods Sprague–Dawley rats were allocated to three groups (dexamethasone, control, and pair-fed group) for the in vivo study. The mice received daily intraperitoneal dexamethasone injections (500 μg/kg) or 0.9% saline for 15 days. To achieve complete NMB, 3.5 mg/kg rocuronium was administered on the sixteenth day. The recovery time to a train-of-four ratio ≥ 0.9 was measured to evaluate the complete recovery following the sugammadex injection. Results Among the groups, no significant differences were observed in the recovery time to a train-of-four ratio ≥ 0.9 following sugammadex administration (P = 0.531). The time to the second twitch of the train-of-four recovery following rocuronium administration indicated that the duration of NMB was significantly shorter in Group D than that in Groups C and P (P = 0.001). Conclusions Chronic exposure to dexamethasone did not shorten the recovery time of sugammadex-induced NMB reversal. However, the findings of this study indicated that no adjustments to sugammadex dosage or route of administration is required, even in patients undergoing long-term steroid treatment

Hypocapnia Attenuates, and Nitrous Oxide Disturbs the Cerebral Oximetric Response to the Rapid Introduction of Desflurane

The aim of this study was to develop a nonlinear mixed-effects model for the increase in cerebral oximetry (rSO2) during the rapid introduction of desflurane, and to determine the effect of hypocapnia and N2O on the model. Twelve American Society of Anesthesiologist physical status class 1 and 2 subjects were allocated randomly into an Air and N2O group. After inducing anesthesia, desflurane was then increased abruptly from 4.0 to 12.0%. The PETCO2, PETDESF and rSO2 were recorded at 12 predetermined periods for the following 10 min. The maximum increase in rSO2 reached +24-25% during normocapnia. The increase in rSO2 could be fitted to a four parameter logistic equation as a function of the logarithm of PETDESF. Hypocapnia reduced the maximum response of rSO2, shifted the EC50 to the right, and increased the slope in the Air group. N2O shifted the EC50 to the right, and reduced the slope leaving the maximum rSO2 unchanged. The N2O-effects disappeared during hypocapnia. The cerebrovascular reactivity of rSO2 to CO2 is still preserved during the rapid introduction of desflurane. N2O slows the response of rSO2. Hypocapnia overwhelms all the effects of N2O

Assessment of Perioperative Sleep Characteristics Using Subjective and Objective Methods: A Secondary Analysis of Prospective Cohort Study.

Perioperative sleep disturbances may impact healing and negatively affect the patients perception of well-being. Therefore, accurately assessing postoperative sleep characteristics is necessary to treat sleep disturbances. This study is a secondary data analysis of research investigating the association between sleep and cognition in a perioperative setting. This study compares sleep characteristics between the St. Marys Hospital Sleep Questionnaire and WatchPAT, a portable sleep apnea testing device. The goal of this study is to compare an objective measurement of sleep quality (WatchPAT) with a traditional questionnaire. One hundred and one patients who underwent elective, noncardiac surgical procedures wore a WatchPAT and completed the St. Marys Hospital Sleep Questionnaire for three nights: two preoperative and one postoperative night. In the preoperative period, a Bland-Altman analysis showed an agreement Watch PAT and the St Marys hospital sleep questionnaire except for sleep fragmentation. A good to fair correlation during the preoperative period was observed with both sleep latency and total sleep time. In the postoperative period, no correlation was observed between the St. Marys Hospital Sleep Questionnaire data and WatchPAT data. Our study indicates that some potential factors affecting sleep and cognition such as admission type, depression, anesthesia type, and sleep apnea may limit patients ability to report their sleep characteristics after surgery. Therefore, relying solely on one sleep assessment method is not advisable

Does the minimal occlusive volume technique provide adequate endotracheal tube cuff pressure to prevent air leakage?: a prospective, randomized, crossover clinical study

Background Methods of determining proper endotracheal tube (ETT) cuff pressure to prevent air leakage include the minimal occlusive volume (MOV) technique, which uses auscultation, and the spirometer technique, which directly measures inspiratory and expiratory breathing volumes. Spirometers may measure even small air leakage, therefore, the spirometer technique requires a higher cuff pressure than the MOV technique to completely seal the airway. This study aimed to evaluate the difference in cuff pressure between the two techniques used to seal the airway. Methods Thirty-five female patients were intubated using an ETT with a cuff, and cuff inflation was performed with both techniques at a 10-min interval in random order—the MOV technique and then the spirometer technique or vice versa. The cuff pressure was measured at each period. Results The cuff pressures were 16.7 ± 4.4 cmH2O and 18.7 ± 5.2 cmH2O for the MOV and spirometer techniques, respectively. The cuff pressure for the spirometer technique was 2.0 cmH2O higher than that for the MOV technique and this difference was statistically significant (95% confidence interval, 0.7–3.3; P = 0.003). Considering the upper end (3.3 cmH2O) of the 95% confidence interval and the size of one scale unit (2.0 cmH2O) of a manometer, the difference in cuff pressure was up to 4 cmH2O in practice. Conclusions Even though the air leakage sound disappears on auscultation, unlike the previous recommendation, the airway sealing would be completed only by increasing the cuff pressure by approximately 4 cmH2O