Neuromuscular Blockade Research Articles

Comprehensive Neurological Examination in Intubated Patients: A Focused Neurology Perspective

The neurological examination of intubated patients presents unique challenges due to the lack of verbal communication and the need for sedation management. This article delves into the methods and best practices for conducting a thorough neurological evaluation in intubated patients, emphasizing the importance of adapting standard neurological assessment techniques to this special population. We explore the use of alternative communication methods, such as eye movements and motor responses, and the interpretation of these findings in the context of critical illness. The article also discusses the implications of sedation and neuromuscular blockade on neurological assessment and provides guidelines for optimizing the accuracy of the examination. By integrating a focused neurology perspective, this review aims to enhance the clinician’s ability to diagnose and monitor neurological status in intubated patients, ultimately improving patient outcomes in the intensive care setting.

The application of surgeon-administered ultrasound-guided popliteal sciatic nerve block in foot and ankle injuries

Introduction Ultrasound-guided popliteal sciatic nerve block has been described as a safe and consistent form of regional anesthesia for foot and ankle surgery. Little studies have been performed to prove the effectiveness of surgeon self-administered regional anesthesia for foot and ankle injury requiring an operation. This study aimed to assess the applicability and safety in surgeon-administered ultrasound-guided popliteal sciatic nerve block in providing anesthesia for foot and ankle fracture. Material and Methods Patients with foot and ankle injury who underwent operation under surgeon-administered ultrasound-guided popliteal sciatic nerve block were evaluated in this retrospective study. A total of 7 patients (3 females and 4 males) with a mean age of 46) were evaluated by the diagnosis, side of injury, comorbidities in American Society of Anesthesiologists Classification (ASA), duration of operation, blood loss, pain control in visual analog scale (VAS) intra-operatively, degree of motor blockage, post-operative pain control and hospital length of stay. Result Average age of the study population was 46. Of all the patients, two of them were of ASA I four of them were of ASA II and one of them was of ASA III. Complete sensory and motor blockages were achieved for all patients. Average operative time was 117 min. Average blood loss was 16.4 mL. Average post-operative inpatient stay was 3.57 days. There was no regional anesthesia-related complication arising from the procedure. Conclusion Surgeon-administered popliteal sciatic nerve block is a safe procedure and can provide excellent pain control throughout the operation according to our experience. Foot and ankle fracture fixation can be performed by orthopedic surgeons under this technique.

A Review on the Poisonous Plant Cleistanthus collinus

Cleistanthus collinus is a toxic plant belonging to the Euphorbiaceae family, and all parts of the plant are poisonous. It is used as suicidal, homicidal, cattle and fish poison and for inducing criminal abortion. The leaves and plant parts are consumed in various forms for homicidal and suicidal and it results in symptoms such as chest pain, dyspnea, central nervous system symptoms, and vision disturbances. There is no specific antidote for the C. collinus poisoning. The percentage of mortality with C. collinus poisoning varies from 20% to 50%, and the mortality depends on the amount and mode of consumption of the leaves. The major phytoconstituents of the plant include ellagic acid, diphyllin, collinusin, cleistanthin A, and cleistanthin B. The two major compounds cleistanthin A and cleistanthin B were evaluated for pharmacological activities such as antineoplastic activity, antiviral activity, diuretic activity, neuromuscular blocking property, alpha receptor blocking property, and antioxidant effect. The current review focuses on the toxicological and pharmacological properties of this plant and its phytoconstituents.

A comparative study on the effect of intrathecal nalbuphine and buprenorphine as an adjuvant to 0.5% hyperbaric bupivacaine in elective infraumbilical surgeries

: Subarachnoid blockade provides excellent operating conditions for lower abdominal, orthopedic, pelvic, urological, gynecological and lower extremity surgery. Most subarachnoid anesthetics are single shot injections and have a definite duration; hence opioids have been used along with local anesthetics in subarachnoid block to prolong its effect, duration, quality of analgesia and minimize the necessity of postoperative analgesics.: The primary objective of the study was to assess the onset and duration of sensory and motor blockade. The secondary objective of the study was to compare the hemodynamics, duration of postoperative analgesia and the complications encountered between the two groups.: A prospective randomized double-blinded study was done in 120 patients divided into two group with 60 in each group as group N and group B by computer generated random numbers. Group N received 0.5% Heavy Bupivacaine (3.2ml) + 0.6mg of Nalbuphine (0.3ml) to a total volume of 3.5 ml and Group B received 0.5% Heavy Bupivacaine (3.2ml) + 90µg of Buprenorphine (0.3 ml) to a total volume of 3.5 ml for spinal anesthesia. The differences between the groups were statistically analyzed with the Independent t test for continuous variables and Pearson’s chi-square test for categorical variables. Observations and results: The onset of sensory block (p=0.303) and motor block (p=0.510) was observed to be faster in group N when compared to group B with statistical insignificance, but the duration of both sensory block (p˂0.001) and motor block (p˂0.001) was more pronounced in group B when compared to group N with statistical significance. The duration of effective analgesia was more pronounced in group B (468.35±30.57 minutes) compared to group N (362.70±35.53 minutes).: The duration of the sensory and motor block with effective postoperative analgesia were more pronounced in buprenorphine compared to nalbuphine and hence intrathecal buprenorphine is a better alternative adjuvant to intrathecal nalbuphine in elective infraumbilical surgeries.

Comparative study of tramadol and nalbuphine as an adjuvant to ropivacaine in supraclavicular block: A cross sectional observational study

Brachial plexus block via supraclavicular approach performed with the help of ultrasound assistance, is a promising anaesthetic alternative for upper limb surgery, when compared with general anaesthesia. It provides good surgical anaesthesia and better post-operative analgesia. We compared the anaesthetic and analgesic efficacy of two additives, nalbuphine and tramadol with 0.375% ropivacaine.A double-blind, cross-sectional study, performed prospectively on 82 patients who were randomly assigned into Group N (41) and Group T (41). Patients were posted for surgical procedure of upper limb under supraclavicular brachial plexus block. Group N received inj. Ropivacaine 0.375% 25 ml plus 1ml (10 mg) of Nalbuphine plus 1ml of normal saline. Patients in Group T received inj. Ropivacaine 0.375% 25 ml with Inj. Tramadol 2 ml (100 mg). Total volume was 27 ml in both groups. Duration of postoperative analgesia was the primary outcome of our study. The secondary outcomes were the sensory and motor block characteristics (onset and duration), change in hemodynamic parameters and side effects.A statistically significant difference was noted in the duration of postoperative analgesia [Group N: 648.27 (± 124.69) minutes, Group T: 514.73 (± 43.15) minutes; P <0.001]. In terms of onset of both sensory and motor block no statistically significant difference was noted. A significant difference was noted in duration of sensory block (Group N: 545.85 ± 118.13 min; Group T: 416.71 ± 50.43 min; P <0.001). The mean duration of motor block was 482.93 ± 120.07 min in nalbuphine group and 356.59 ± 43.74 min in tramadol group; P <0.001.Nalbuphine 10mg is a better adjuvant to 0.375% ropivacaine when compared with tramadol 100 mg. It prolongs the duration of sensory block and motor block and increases the duration of analgesia postoperatively.

Feasibility of the enhanced neuromuscular blockade recovery protocol with selective use of sugammadex in thyroid surgery with intraoperative neuromonitoring.

To investigate feasibility of utilizing enhanced neuromuscular blocking agents with selective recovery protocol during thyroid surgery with intraoperative neuromonitoring (IONM). Two-hundred and ninety patients were randomized into two groups: group A 0.3 mg/kg rocuronium and group B 0.6 mg/kg. Sugammadex 2 mg/kg was injected if needed followed initial vagal stimulation (V0). Electromyography signals from vagus and recurrent laryngeal nerves before and after resection were recorded as V1, V2, R1, and R2. In group B, 30 patients (20.7%) had V0 signals <100 μV, compared to 9 (6.2%) in group A. After sugammadex administration, 144 patients (99.3%) in both groups achieved positive V1 signals. Group B demonstrated a shorter surgical time from rocuronium injection to V2 stimulation compared to group A, accompanied by a significantly lower incidence of intraoperative body movement (0 vs. 16 patients). 0.6 mg/kg rocuronium with selective use 2 mg/kg sugammadex for IONM in thyroid surgery can meet both anesthesia and surgery demands.

Comparison of efficacy of intrathecal hyperbaric ropivacaine and hyperbaric bupivacaine in terms of enhanced recovery after surgery (ERAS) for ACL reconstructions

: Bupivacaine is the drug of choice in spinal anaesthesia (SA), while Ropivacaine with its comparatively shorter duration of motor block allows early mobilization post ACL reconstruction surgery which is a crucial factor in Early Recovery after Surgery. : In this randomized double-blind comparative study of a total of 60 patients irrespective of gender undergoing ACL reconstruction surgery were studied. After Administration of SA to group R (2.5ml of 0.75% Heavy Ropivacaine) &amp; group B (2.5ml of 0.5% Bupivacaine) both were compared for their post-operative effects with Bromage score, Aldrete score &amp; Visual Analogue Score. : The time required for complete regression of motor blockade in group R (144.5+26.1 mins) &amp;#60; group B (181±21.3mins) which allowed for early mobilization which over all provides better and faster recovery.: Hyperbaric Ropivacaine when compared to Bupivacaine promises better results in terms of early ambulation and intraoperative hemodynamic stability promoting ERAS in patients undergoing ACL reconstruction surgeries. Promoting ERAS policy will reduce the duration of hospital stay, thereby improving the cost-effectiveness of health services.

Intravenous magnesium sulfate improves orotracheal intubation conditions: A randomized clinical trial

BackgroundMuscle relaxation facilitates orotracheal intubation, but in some situations, neuromuscular blocking agents may be contraindicated. AimTo study the effect of intravenous magnesium sulfate perfusion before induction on orotracheal intubation conditions and the pressor response upon intubation. MethodsThis prospective, randomized, double-blind trial compared magnesium sulfate with saline solution as a placebo. The patients were randomized into two groups: the magnesium group (Group Mg+), which received 50 mg/kg of magnesium sulfate in 100 ml of saline 15 min before induction of anesthesia, and the saline group (Group Mg-), which received only 100 ml of saline 15 min before induction of anesthesia without magnesium sulfate. The induction in both groups was performed without neuromuscular blocking agents.Intubation conditions in both groups were compared using the Copenhagen consensus conference: ease of laryngoscopy, vocal cord position and/or movement, and response to intubation or cuff (cough or diaphragmatic movement). Intubation conditions were considered acceptable (excellent or good) or unacceptable (poor). Systolic, diastolic arterial pressures and heart rate were also recorded during the study. ResultsIn total, 76 patients (38 in each group) were included in this study. Clinically acceptable intubation conditions were significantly more observed in the magnesium group Mg + compared to the saline group Mg-: 36 patients (95 %) vs. 15 patients (39 %) (P < 0.001).Hemodynamic stability was more observed in the magnesium group, with a statistically significant lower heart rate throughout Mg + compared to the saline group. ConclusionAdministration of magnesium sulfate before induction of anesthesia significantly improved intubation conditions without the need for neuromuscular blocking agents.

Impact of neuromuscular block on myocardial injury after non-cardiac surgery (MINS) incidence in the early postoperative stage of older patients undergoing laparoscopic colorectal cancer resection: a randomized controlled study

BackgroundMyocardial injury after non-cardiac surgery (MINS) is a common and serious complication in older patients. This study investigates the impact of neuromuscular block on the MINS incidence and other cardiovascular complications in the early postoperative stage of older patients undergoing laparoscopic colorectal cancer resection.Methods70 older patients who underwent laparoscopic colorectal cancer resection were separated into the deep neuromuscular block group and moderate neuromuscular block group for 35 cases in each group (n = 1:1). The deep neuromuscular block group maintained train of four (TOF) = 0, post-tetanic count (PTC) 1–2, and the moderate neuromuscular block group maintained TOF = 1–2 during the operation. Sugammadex sodium was used at 2 mg/kg or 4 mg/kg for muscle relaxation antagonism at the end of surgery. The MINS incidence was the primary outcome and compared with Fisher's exact test. About the secondary outcomes, the postoperative pain was analyzed with Man-Whitney U test, the postoperative nausea and vomiting (PONV) and the incidence of cardiovascular complications were analyzed with Chi-square test, intraoperative mean artery pressure (MAP) and cardiac output (CO) ratio to baseline, length of stay and dosage of anesthetics were compared by two independent samples t-test.ResultsMINS was not observed in both groups. The highest incidence of postoperative cardiovascular complications was lower limbs deep vein thrombosis (14.3% in deep neuromuscular block group and 8.6% in moderate neuromuscular group). The numeric rating scale (NRS) score in the deep neuromuscular block group was lower than the moderate neuromuscular block group 72 h after surgery (0(1,2) vs 0(1,2), P = 0.018). The operation time in the deep neuromuscular block group was longer (356.7(107.6) vs 294.8 (80.0), min, P = 0.008), the dosage of propofol and remifentanil was less (3.4 (0.7) vs 3.8 (1.0), mg·kg−1·h−1, P = 0.043; 0.2 (0.06) vs 0.3 (0.07), μg·kg−1·min−1, P < 0.001), and the length of hospital stay was shorter than the moderate neuromuscular block group (18.4 (4.9) vs 22.0 (8.3), day, P = 0.028). The differences of other outcomes were not statistically significant.ConclusionsMaintaining different degrees of the neuromuscular block under TOF guidance did not change the MINS incidence within 7 days after surgery in older patients who underwent laparoscopic colorectal cancer resection.Trial registrationThe present study was registered in the Chinese Clinical Trial Registry (10/02/2021, ChiCTR2100043323).

Sugammadex use in pediatric patients with stage IV-V chronic kidney disease in a quaternary referral hospital: a case series

BackgroundSugammadex is a pharmacologic agent that provides rapid reversal of neuromuscular blockade via encapsulation of the neuromuscular blocking agent (NMBA). The sugammadex-NMBA complex is primarily cleared through glomerular filtration from the kidney, raising the possibility that alterations in renal function could affect its elimination. In pediatric patients, the benefits of sugammadex have led to widespread utilization; however, there is limited information on its application in pediatric renal impairment. This study examined sugammadex use and postoperative outcomes in pediatric patients with severe chronic renal impairment at our quaternary pediatric referral hospital.MethodsAfter IRB approval, we performed a retrospective analysis in pediatric patients with stage IV and V chronic kidney disease who received sugammadex from January 2017 to March 2022. Postoperative outcomes studied included new or increased respiratory requirement, unplanned intensive care unit (ICU) admission, postoperative pneumonia, anaphylaxis, and death within 48 h postoperatively, unplanned deferral of intraoperative extubation, and repeat administrations of NMBA reversal after leaving the operating room.ResultsThe final cohort included 17 patients ranging from 8 months to 16 years old. One patient required new postoperative noninvasive ventilation on postoperative day 2, which was credited to hypervolemia. Another patient had bronchospasm intraoperatively resolving with medication, which could not definitively be associated sugammadex administration. There were no instances of deferred extubation, unplanned ICU or need for supplemental oxygen after tracheal extubation identified.ConclusionNo adverse effects directly attributable to sugammadex in pediatric patients with severe renal impairment were detected. There may be a role for utilization of sugammadex for neuromuscular reversal in this population.

Comparison of the classical approach and costoclavicular approach of ultrasound-guided infraclavicular block: A systematic review and meta-analysis.

The infraclavicular brachial plexus block (ICB) provides analgesia and anaesthesia of the upper limb. It is given using the classical or the more recently described costoclavicular (CC) approach at the level of cords. This systematic review aimed to assess which approach is better for the ICB in terms of onset, performance, and safety. This PROSPERO (vide registration number CRD42022361636) registered meta-analysis included randomised trials of patients undergoing upper limb surgery in ultrasound-guided ICB from MEDLINE, EMBASE, SCOPUS, and IRCTP from inception to March 2023. The quality of evidence was assessed using GradePro software. The primary outcomes were sensory and motor block onset time and the number of patients having complete block at 30 minutes. Secondary outcomes included block performance time (BPT), number of attempts, duration of the block, and any incidence of complications. Five trials with 374 adult patients (classic = 185, CC = 189) were included. No significant difference was found in the sensory (Mean difference (MD): 1.44 minutes [95% confidence interval (CI): 3.06, 5.95]; I2 = 95%; very low level of evidence (LOE); P = 0.53) and motor block onset times (MD: 0.83 minutes [95% CI: 0.96, 2.62]; I2 = 84%; very low LOE P = 0.36) and BPT (MD: 5.06 seconds [95% CI: 38.50, 48.63]; I2 = 98%; very low LOE; P = 0.82) in classic and CC approach of ICB. Trial sequential analysis revealed our sample size to be 0.65% of the required sample size to achieve 80% power, deeming our study underpowered. Costoclavicular approach was not superior or inferior to the classical technique for infraclavicular brachial plexus block. However, the quality of evidence is low and further studies are needed to corroborate the findings.

Cortical modulations before lower limb motor blocks are associated with freezing of gait in Parkinson’s disease: an EEG source localization study

BackgroundFreezing of gait (FOG) is a debilitating symptom of Parkinson’s disease (PD) characterized by paroxysmal episodes in which patients are unable to step forward. A research priority is identifying cortical changes before freezing in PD-FOG. MethodsWe tested 19 patients with PD who had been assessed for FOG (n=14 with FOG and 5 without FOG). While seated, patients stepped bilaterally on pedals to progress forward through a virtual hallway while 64-channel EEG was recorded. We assessed cortical activities before and during lower limb motor blocks (LLMB), defined as a break in rhythmic pedaling, and stops, defined as movement cessation following an auditory stop cue. This task was selected because LLMB correlates with FOG severity in PD and allows recording of high-quality EEG. Patients were tested after overnight withdrawal from dopaminergic medications (“off” state) and in the “on” medications state. EEG source activities were evaluated using individual MRI and standardized low resolution brain electromagnetic tomography (sLORETA). Functional connectivity was evaluated by phase lag index between seeds and pre-defined cortical regions of interest. ResultsEEG source activities for LLMB vs. cued stops localized to right posterior parietal area (Brodmann area 39), lateral premotor area (Brodmann area 6), and inferior frontal gyrus (Brodmann area 47). In these areas, PD-FOG (n=14) increased alpha rhythms (8-12 Hz) before LLMB vs. typical stepping, whereas PD without FOG (n=5) decreased alpha power. Alpha rhythms were linearly correlated with LLMB severity, and the relationship became an inverted U-shape when assessing alpha rhythms as a function of percent time in LLMB in the “off” medication state. Right inferior frontal gyrus and supplementary motor area connectivity was observed before LLMB in the beta band (13-30 Hz). This same pattern of connectivity was seen before stops. Dopaminergic medication improved FOG and led to less alpha synchronization and increased functional connections between frontal and parietal areas. ConclusionsRight inferior parietofrontal structures are implicated in PD-FOG. The predominant changes were in the alpha rhythm, which increased before LLMB and with LLMB severity. Similar connectivity was observed for LLMB and stops between the right inferior frontal gyrus and supplementary motor area, suggesting that FOG may be a form of “unintended stopping.” These findings may inform approaches to neurorehabilitation of PD-FOG.

Programmed intermittent epidural bolus regimen vs continuous epidural infusion: a retrospective study of motor block and obstetric outcomes using the Robson’s Ten Group Classification System

BackgroundUse of a programmed intermittent epidural bolus (PIEB) regimen during labour is associated with several benefits over a continuous epidural infusion (CEI), including reduced local anaesthetic consumption and reduced risk of motor block. We hypothesise that the benefits of a PIEB regimen may vary according to the Robson Ten Group Classification System (TGCS). The aim of this study was to determine if introduction of a PIEB regimen was associated with reduced incidence of motor block. We also wished to examine changes in obstetric outcomes following PIEB introduction across the Robson TGCS. MethodsThis was a single-centre retrospective cohort study. Data were collected over two three-month periods before and after PIEB introduction. The primary outcome was the incidence of motor block. Maternal and obstetric outcomes across Robson Groups 1–4 were analysed. ResultsIntroduction of PIEB was associated with reduced incidence of motor block (28.4% (95% CI 25.7% to 31.3%) vs 22.4%, (95% CI 19.9% to 25.2%), difference 5.9% (95% CI 1.0% to 21.1%), P=0.003), with no association with changes in rates of caesarean section, operative vaginal delivery or other obstetric outcomes. Use of a PIEB regimen was associated with reduced incidence of motor block in Robson Group 4a (20.3% (16.0%, 28.0%) vs 12.0%, (7.6%, 16.4%), difference 9.9% (95% CI −17.4% to −2.4%) P=0.009). There were no significant changes in other outcomes assessed across Robson TGCS. ConclusionIntroduction of PIEB for maintenance of labour analgesia was associated with reduced incidence of motor block in our institution compared with CEI. Presenting results according to Robson’s TGCS in future studies may allow better elucidation of the impact of neuraxial analgesia on maternal and obstetric outcomes.

Incidence, Associated Factors, and Behavioral Consequences of Intraoperative Awareness and Dreams During General Anesthesia Among Adult Patients: A Prospective Cohort Study.

Background The intraoperative awareness with recall phenomenon involves the memory of intraoperative events. The reported incidence is 0.001%. Awareness is rare intraoperatively but has profound implications. This research aimed to study intraoperative awareness and dream experiences in the Omani population undergoing general anesthesia. Methods This prospective cohort study involving 300 adult patients was conducted at a tertiary-level hospital between July and December 2021. Awareness was assessed in the post-anesthesia care unit and then at home on the seventh day and one month telephonically using a modified Brice questionnaire. The study's primary outcome was the incidence of IOA and dreams in adult Omani patients undergoing GA. The secondary outcome was identifying the factors associated with intraoperative awareness and dreams under GA. Results In this study, the incidence of awareness was 0.3%while 7.6% of patients reported intraoperative dreams. The patient who experienced IOA underwent an endoscopic retrograde cholangiopancreatography under GA with neuromuscular blockade and had a prolonged recovery. A total of 49.33% developed psychological effects postoperatively; anxiety, irritability, fear of surgery, change in memory, and repetitive nightmares were the most common ones. Because of the limited sample size, no factor associated significantly with these outcomes was found. Conclusion This study observed a higher incidence of intraoperative awareness and dreams. Awareness might be due to prolonged recovery and the use of neuromuscular blocking agents, but a focused study is required to confirm this finding. The incidence of intraoperative dreams and postoperative psychological effects of GA was also high. It may be worth exploring these findings with larger population-based research.

A Comparison of Analgesic and Recovery Profiles of Ketamine, Lignocaine, and Dexmedetomidine (KeLiDex) Versus Fentanyl-Based Anesthesia in Laparoscopic Nephrectomies: A Randomized, Single-Blind, Pilot Study.

In the search for opioid-free anesthesia, notable numbers of drugs, singly or in combinations, have been tested with variable results. However, most of the drugs used are not as strong as opioids. Even if some non-opioid drugs are potent enough, they cause significant untoward effects, necessitating the use of lower effective dosages of multiple drugs as a substitute. The present pilot study evaluated low-dose combinations of ketamine, lignocaine, and dexmedetomidine (KeLiDex) against fentanyl-based anesthesia for analgesia and recovery profiles in laparoscopic nephrectomies. Twenty patients (10 in each group) randomly received KeLiDex or fentanyl infusion as an analgesic component for balanced general anesthesia. Entire patients also received paracetamol and quadratus lumborum block-2. Anesthesia depth, neuromuscular blockade, and reversal were standardized. Intraoperative hemodynamic variation, time to extubation after reversal (T-tEAR) administration, postanesthesia care unit (PACU) discharge readiness assessed using modified Aldrete score, sedations using Richmond Agitation Sedation Scale, postoperative pain, and rescue analgesia consumptions were compared using different validated scales. P-value <0.05 was considered significant. The KeLiDex group had a significantly lower heart rate (HR) between 45-90 minutes and at the time of reversal. Mean arterial pressure (MAP) (mean ± standard deviation (SD)) differed significantly at only a 60-minute interval (KeLiDex group 80.90 ± 9.50 versus fentanyl group 92.60 ± 16.13 mmHg, p-value 0.041). The Friedman test for change in HR and MAP over time within each group was also insignificant. The mean ± SD of T-tEAR was 6.37 ± 2.13 in KeLiDex, and 8.18 ± 2.92 minutes in the fentanyl group, p-value 0.27. Sedation scores, Modified Alderette scores, pain scores, and rescue analgesic requirements were also comparable. KeLiDex could effectively control hemodynamics and pain both at rest and in movements in line with fentanyl-based anesthesia for laparoscopic nephrectomies. Further, recovery from the anesthesia, sedation, and PACU discharge readiness were similar.

Management of severe acute respiratory distress syndrome in Australia and New Zealand (SAGE-ANZ): An observational study

ObjectiveAcute respiratory distress syndrome (ARDS) is associated with significant mortality, morbidity, and cost. We aimed to describe characteristics and management of adult patients admitted to intensive care units (ICUs) in Australia and New Zealand with moderate-severe ARDS, to better understand contemporary practice. DesignBi-national, prospective, observational, multi-centre study. Setting19 ICUs in Australia and New Zealand. ParticipantsMechanically ventilated patients with moderate-severe ARDS. Main outcome measuresBaseline demographic characteristics, ventilation characteristics, use of adjunctive support therapy and all-cause mortality to day 28. Data were summarised using descriptive statistics. Results200 participants were enrolled, mean (±SD) age 55.5 (±15.9) years, 40% (n = 80) female. Around half (51.5%) had no baseline comorbidities and 45 (31%) tested positive for COVID-19. On day 1, mean SOFA score was 9 ± 3; median (IQR) PaO2/FiO2 ratio 119 (89, 142), median (IQR) FiO2 70% (50%, 99%) and mean (±SD) positive end expiratory pressure (PEEP) 11 (±3) cmH2O. On day one, 10.5% (n = 21) received lung protective ventilation (LPV) (tidal volume ≤6.5 mL/kg predicted body weight and plateau pressure or peak pressure ≤30 cm H2O). Adjunctive therapies were received by 86% (n = 172) of patients at some stage from enrolment to day 28. Systemic steroids were most used (n = 127) followed by neuromuscular blockers (n = 122) and prone positioning (n = 27). Median ventilator-free days (IQR) to day 28 was 5 (0, 20). In-hospital mortality, censored at day 28, was 30.5% (n = 61). ConclusionsIn Australia and New Zealand, compliance with evidence-based practices including LPV and prone positioning was low in this cohort. Therapies with proven benefit in the treatment of patients with moderate-severe ARDS, such as lung protective ventilation and prone positioning, were not routinely employed.

Shortened time to neuromuscular recovery with lower doses of rocuronium in elderly patients.

The effect of neuromuscular blocking agents may be reversed by administration of neostigmine, when two twitches are present using train-of-four (TOF) stimulation. However, in elderly patients, limited data are available about when to administer neostigmine. We hypothesised that time to two twitches after TOF (TOF-2) was shorter after rocuronium 0.6 mg/kg than after rocuronium 0.9 mg/kg. Also, we hypothesised that time to TOF-2 would be shorter after rocuronium 0.3 mg/kg than after rocuronium 0.6 mg/kg. This was a secondary analysis of 50 elderly patients > 80 years; 16 patients received rocuronium 0.6 mg/kg, another 16 patients received rocuronium 0.9 mg/kg; and, finally, 18 patients received rocuronium 0.3 mg/kg. Patients received total intravenous anaesthesia, and neuromuscular block was monitored with acceleromyography. Time to TOF-2 was shorter after rocuronium 0.6 mg/kg than after rocuronium 0.9 mg/kg: 37 min. versus 59 min. (difference: 22 min. (95% confidence intervals (CI): 10 to 33 min.), p = 0.0007). Time to TOF-2 after rocuronium 0.3 mg/kg was shorter than after rocuronium 0.6 mg/kg: 19 min. versus 37 min. (difference: 18 min. (95% CI: 11 to 25 min.), p = 0.00006). However, only 33% of the patients receiving 0.3 mg/kg obtained full effect i.e. TOF-0. Time to TOF-2 was shorter after rocuronium 0.6 mg/kg than after 0.9 mg/kg and shorter after rocuronium 0.3 mg/kg than after 0.6 mg/kg. This work was supported by departmental sources. This study was a secondary analysis of two clinical trials. gov (NCT04512313), (NCT03857750).

Effect of dexmedetomidine infusion on characteristics of spinal anesthesia with hyperbaric bupivacaine: A randomized controlled trial

Dexmedetomidine is a highly selective and potent α2 agonist having both sedative and analgesic properties. This study was aimed to assess the effects of intravenous dexmedetomidine on sensory, motor, haemodynamic parameters and sedation during subarachnoid block (SAB) with 0.5% hyperbaric bupivacaine. Sixty patients undergoing infraumbilical and lower limb surgeries were allocated into 2 groups, group D (n=30) received dexmedetomidine infusion at the rate of 0.5 µg/kg/h over an hour prior to SAB and continued till the end of surgery whereas patients in group C (n=30) received similar volume of normal saline infusion for the same duration. Onset of sensory block was 63.77 ± 7.42 s in group D compared with 126.2 ± 12.83s in group C. Two segment regression time was 177.03 ± 11.64 min in group D and 85.67 ± 10.32 min in group C and analgesia duration was 287.67 ± 14.84 min in group D and 149 ± 13.16 min in group C. Onset of motor block was 3.95 ± 0.65 min in group D and 4.5 ± 0.62 min in group C. Motor blockade duration was prolonged in group D compared with group C. There was significant difference between the groups in respect to block characteristics. Administration of intravenous dexmedetomidine during SAB hastens the onset and prolongs the duration of sensory and motor block. It also provides conscious sedation and additional analgesia.

The Influence of Acid-Base Balance on Anesthetic Muscle Relaxants: A Comprehensive Review on Clinical Applications and Mechanisms.

Muscle relaxants have broad application in anesthesiology. They can be used for safe intubation, preparing the patient for surgery, or improving mechanical ventilation. Muscle relaxants can be classified based on their mechanism of action into depolarizing and non-depolarizing muscle relaxants and centrally acting muscle relaxants. Non-depolarizing neuromuscular blocking drugs (NMBDs) (eg, tubocurarine, atracurium, pipecuronium, mivacurium, pancuronium, rocuronium, vecuronium) act as competitive antagonists of nicotine receptors. By doing so, these drugs hinder the depolarizing effect of acetylcholine, thereby eliminating the potential stimulation of muscle fibers. Depolarizing drugs like succinylcholine and decamethonium induce an initial activation (depolarization) of the receptor followed by a sustained and steady blockade. These drugs do not act as competitive antagonists; instead, they function as more enduring agonists compared to acetylcholine itself. Many factors can influence the duration of action of these drugs. Among them, electrolyte disturbances and disruptions in acid-base balance can have an impact. Acidosis increases the potency of non-depolarizing muscle relaxants, while alkalosis induces resistance to their effects. In depolarizing drugs, acidosis and alkalosis produce opposite effects. The results of studies on the impact of acid-base balance disturbances on non-depolarizing relaxants have been conflicting. This work is based on the available literature and the authors' experience. This article aimed to review the use of anesthetic muscle relaxants in patients with acid-base disturbances.

The Effect of Anesthesia on Passive Ankle Dorsiflexion.

Equinus contractures can commonly be due to contractures of gastrocnemius muscle or combined contractures of the gastrocnemius-soleus Achilles tendon complex. The decision to release part or all of the gastrocnemius-soleus Achilles tendon complex is often assessed intraoperatively while the patient is under anesthesia. It remains unknown whether the administration of general anesthesia affects the measurement of passive ankle dorsiflexion. The unaffected, nonoperative limb on 46 foot and ankle patients underwent a Silfverskiold test measuring passive ankle dorsiflexion preoperatively and intraoperatively after administration of general anesthesia using an instrumented force-angular displacement goniometer. To determine clinical significance, we surveyed experienced surgeons to estimate the perceived minimally detectable clinical accuracy for measuring passive ankle dorsiflexion. Forty-six subjects were included with mean age of 42 ± 14.8 years, mean body mass index of 26.2 ± 4.9, and 52% female. The mean change in dorsiflexion values from before anesthesia to after the administration of general anesthesia was 1.9 degrees with 10 lb of pressure with knee extended (E10), 2.3 degrees with 20 lb of pressure with knee extended (E20), 2.8 degrees with 10 lb of pressure with knee flexed (F10), and 2.3 degrees with 20 lb of pressure with knee flexed (F20) (all P < .001). Thirty-three of 45 (73%) surgeons responded to the survey; all thought their minimally detectable clinical accuracy was 5 degrees or greater. After the administration of general anesthesia, a small but likely not clinically detectable increase in passive ankle dorsiflexion occurs. The common clinical practice of making intraoperative treatment decisions regarding the presence of a gastrocnemius-soleus driven equinus contractures after general anesthesia without use of paralytic agents appears reasonable given the magnitude of the changes identified in this study.