The undesirable effects of neuromuscular blocking drugs

Double epidural catheter technique in a patient with severe COPD undergoing major abdominal surgery: A case report

INTRODUCTION AND IMPORTANCE

Chronic Obstructive Pulmonary Disease (COPD) leads to the development of postoperative pulmonary complications (PPC), such as atelectasis, pneumonia and respiratory failure. The use of epidural anesthesia, alone or combined with general anesthesia, is known to reduce the incidence of PPC and shorten tracheal intubation time. In major procedures involving both the lower and upper abdomen, central neuraxial block at a single level may be inadequate to provide sufficient metameric extension of anesthesia. This limitation could be overcome with the use of double epidural catheter (DEC), has proved effective in diverse surgical scenarios.

CASE PRESENTATION AND CLINICAL DISCUSSION

We present the case of a woman affected by moderate-severe COPD scheduled for major abdominal cytoreductive surgery due to ovarian malignancy with planned xypho-pubic laparotomy. We developed and implemented a DEC-based strategy for perioperative pain management based on the extent of surgical incision and the high risk of difficult weaning from ventilation and PPC. We used intraoperative monitoring to guarantee adequate antinociception throughout the entire 350 min long demolitive surgical procedure. No additional top-ups of intravenous analgesia or neuromuscular blocking agent (NMBA) was needed during surgery; at the end of the procedure, the patient was extubated in the operating theatre, maintaining adequate respiratory function during the whole postoperative period.

CONCLUSIONS

The DEC technique could be beneficial for patients undergoing cytoreductive surgery. In our case, this technique granted optimal analgesic coverage and was instrumental in achieving fast weaning from mechanical ventilation and early tracheal extubation. Systematic studies on this subject are warranted.

MRGPRX2 and Adverse Drug Reactions

Many adverse reactions to therapeutic drugs appear to be allergic in nature, and are thought to be triggered by patient-specific Immunoglobulin E (IgE) antibodies that recognize the drug molecules and form complexes with them that activate mast cells. However, in recent years another mechanism has been proposed, in which some drugs closely associated with allergic-type events can bypass the antibody-mediated pathway and trigger mast cell degranulation directly by activating a mast cell-specific receptor called Mas-related G protein-coupled receptor X2 (MRGPRX2). This would result in symptoms similar to IgE-mediated events, but would not require immune priming. This review will cover the frequency, severity, and dose-responsiveness of allergic-type events for several drugs shown to have MRGPRX2 agonist activity. Surprisingly, the analysis shows that mild-to-moderate events are far more common than currently appreciated. A comparison with plasma drug levels suggests that MRGPRX2 mediates many of these mild-to-moderate events. For some of these drugs, then, MRGPRX2 activation may be considered a regular and predictable feature after administration of high doses.

The association between residual neuromuscular blockade (RNMB) and critical respiratory events: a prospective cohort study

Background

Inadequate neuromuscular recovery might impair pulmonary function among adult patients who undergo general anaesthesia and might thus contribute to critical respiratory events in the post-anaesthesia care unit (PACU). The pilot study aims to understand the baseline incidence of residual neuromuscular blockade (RNMB) and postoperative critical respiratory events (CREs), which are described in a modified Murphy’s criteria in the PACU.

Method

This is a prospective cohort study from January to March 2017 from a tertiary hospital in Saudi Arabia with thirty adult patients over 18 years old scheduled for elective surgery under general anaesthesia with neuromuscular blocking drugs (NMBDs) who were enrolled in the study. The Mann-Whitney U tests, chi-square tests and independent-samples T tests were used. The train-of-four (TOF) ratios were measured upon arrival in the PACU by using acceleromyography with TOF-Scan. Subjects’ demographics, perioperative data and the occurrence of postoperative CREs in the PACU were recorded.

Results

Twenty-six (86.7%) patients out of thirty in the study have received rocuronium as NMBDs whilst neostigmine as a reversal drug with only 23 (76.7%). The incidence of RNMB (TOF ratio < 0.9) was in 16 patients (53.3%). The incidence of RNMB was significantly higher in female patients (p = 0.033), in patients who had not undergone quantitative neuromuscular monitoring before extubation (p = 0.046) and in patients with a shorter duration of surgery (p = 0.001). Postoperative CREs occurred in twenty patients (66.7%), and there were significantly more of these CREs among patients with RNMB (p = 0.001). In addition, a statistically significant difference was observed in the occurrence of CREs according to body mass index (p = 0.047).

Conclusion

This research showed that RNMB is a significant contributing factor to the development of critical respiratory events during PACU stay. Therefore, routine quantitative neuromuscular monitoring is recommended to reduce the incidence of RNMB.

Serious bronchospasm induced by cisatracurium besylate: A case report

RATIONALE

Cis-atracurium as an intermediate-acting non-depolarizing neuromuscular blocker is widely used clinically with less causing cyclic fluctuations and less histamine release. As the use rate increases, allergic reactions and anaphylactoid reactions caused by cis-atracurium increase.

PATIENT CONCERNS

A 23-year-old woman underwent laparoscopic bariatric surgery. Airway spasm occurred after anesthesia induction and the operation was suspended. After adjustment, the anesthesia was performed with the same anesthetic scheme again. After induction, skin flushing and airway resistance increased, then the symptoms were relieved. When the cis-atracurium was given again, the symptoms of airway spasm reappeared immediately, and after communicating with the family, the operation was successfully completed with rocuronium.

DIAGNOSES

Serious bronchospasm induced by cisatracurium besylate.

INTERVENTIONS

The patient was undergone assisted ventilation with continuous positive airway pressure (CPAP) and aminophylline 250 mg, methylprednisolone 80 mg were given intravenously.

OUTCOMES

There was no any obvious discomfort in the patient's self-report during the next day's visit. The patient was discharged 7 days later. No abnormalities were observed during following 4 weeks.

LESSONS

Although the anaphylactoid reactions caused by cis-atracurium are rare, the bronchospasm and anaphylactic shock caused by it greatly increase the risk of anesthesia, which should be taken seriously by clinicians. Increased vigilance in diagnosis, and treatment are essential to prevent aggravation and further complication.

Minireview: Mas-related G protein-coupled receptor X2 activation by therapeutic drugs

Symptoms that resemble allergic reactions, such as pruritus, flushing, and hypotension, are common side effects of therapeutic drugs. In a true allergic reaction, Immunoglobulin E (IgE) antibodies recognize the drug and trigger mediator release from mast cells through cross-linking of IgE receptors. However, many drugs can bypass this pathway and can activate mast cells directly through MRGPRX2, a G protein-coupled receptor that responds to a wide range of small molecules, peptides, and proteins that have little in common except for a net positive charge. This review will provide an overview of MRGPRX2, including its expression pattern, studies of its pharmacology, and its orthologs. It also will review evidence for MRGPRX2 activation by many drugs closely associated with these reactions.

Efficacy and Safety of Neuromuscular Blockade in Overweight Patients Undergoing Nasopharyngeal Surgery

BACKGROUND Adequate muscle relaxation and rapid recovery of neuromuscular function are essential in the perioperative period. We therefore compared various anesthetic regimens of neuromuscular blockers and antagonists administered to overweight patients undergoing nasopharyngeal surgery. MATERIAL AND METHODS This prospective, randomized, double-blind study was conducted in overweight patients undergoing nasopharyngeal surgery. We randomly assigned 102 patients into 3 groups (each n=34) treated with various muscle relaxant agents and antagonists: rocuronium and sugammadex (Group RS), rocuronium and neostigmine (Group RN), and cisatracurium and neostigmine (Group CN). Then, we compared the efficacy and safety indexes of the 3 groups. RESULTS Onset times of muscular relaxation in Group RS and Group RN (110 s and 120 s) were shorter than in Group CN (183 s). Time from administration of antagonist to recovery of the TOF ratio to 0.9 was shorter in Group RS (3.3 min) than in other groups (20.7 min and 19.1 min, respectively). The incidence of postoperative residual curarization (PORC) was significantly lower in Group RS (5.9%) than in the other 2 groups (both 41.2%). The hemodynamic parameter changes before extubation were significantly higher in Group RN and Group CN than in Group RS. The postoperative pain scores were lowest in Group RS. CONCLUSIONS For overweight patients undergoing nasopharyngeal surgery, the use of rocuronium with sugammadex had the shortest onset time of neuromuscular relaxation, accelerated the reversion of neuromuscular blockade, effectively reduced the occurrence of PORC, relieved postoperative pain, and maintained hemodynamic stability before extubation. The combination of rocuronium and sugammadex may be the best anesthetic regimen for overweight patients undergoing nasopharyngeal surgery.

Postanesthetic skin erythema due to succinylcholine versus atracurium

Intraoperative anaphylactic reactions may range from mild, erythema-like to anaphylactic shock, with tension crash and bronchospasm. The substances considered to be most responsible for the occurrence of intraoperative allergic reactions are neuromuscular blocking agents, antibiotics and latex. Recent studies have identified a new receptor, Mas-Related G-Protein-coupled Receptor X2 (MRGPRX2), considered as a target for some neuromuscular blockers such as atracurium, rocuronium or fluoroquinolone, resulting in pseudoallergic or anaphylactoid reactions. Induction of anesthesia can use both depolarizing myorelaxants, useful especially in emergency situations, in the patient with gastric plenitude or at high risk of intubation, and non-depolarizing myorelaxants such as atracurium, cisatracurium and rocuronium. Succinylcholine has a short time of action and it is rapidly metabolized. Atracurium, although having a slightly longer time to action, has the benefit of a low risk of increased levels of potassium in blood, which is extremely important in patients with cardiac pathology or associated kidney diseases. The present study compared the side effects of systemic anesthesia with succinylcholine vs. atracurium.

Comparison of the neuromuscular blocking effects of cisatracurium during isoflurane or propofol anesthesia in dogs

OBJECTIVE

To compare the neuromuscular blocking effects of cisatracurium during isoflurane versus propofol anesthesia in dogs.

STUDY DESIGN

Prospective, randomized study.

ANIMALS

A total of 20 healthy, client-owned dogs (16 females, four males) weighing 12.5-22 kg and aged 1-8 years.

METHODS

Dogs undergoing elective surgery were randomized in equal numbers to an isoflurane (ISO) or propofol (PPF) group. Other drugs used during anesthesia were equal between groups. Single-twitch (ST) stimulation was used to monitor neuromuscular response. After recording the baseline ST (T0), cumulative doses of cisatracurium (0.05 mg kg^-1) were administered intravenously until ST/T0 ≤5%. Effective doses 50 (ED₅₀) and 95 (ED₉₅) of cisatracurium in each group were calculated from group dose-response curves. Recovery of ST (TR) was defined as spontaneous recovery of ST to 80-120% of T0 remaining stable for 2 minutes. The ST after each dose of cisatracurium, duration 25% (time after the last dose until 25% recovery of TR), recovery index (time to recovery from 25% to 75% of TR) and duration to TR (time after the last dose until recovery of TR) were recorded.

RESULTS

Incremental doses of cisatracurium, median (range), were 2 (1-3) in ISO and 4 (2-5) in PPF to achieve ≥95% depression of ST/T0 (p < 0.01). ED₅₀ and ED₉₅ were 20 μg kg^-1 and 117 μg kg^-1 in ISO and 128 μg kg^-1 and 167 μg kg^-1 in PPF, respectively. The duration 25%, recovery index and duration to TR, median (range), were longer in ISO [22.6 (10.3-24.3), 5.3 (3.0-7.8) and 36.1 (20.1-49.7) minutes, respectively] than in PPF [10.2 (6.8-16.5), 3.0 (2.0-3.8) and 17.7 (14.2-28.7) minutes, respectively] (p < 0.01).

CONCLUSIONS AND CLINICAL RELEVANCE

Cisatracurium-induced neuromuscular blockade was significantly enhanced and prolonged by isoflurane compared with propofol.

Anesthetic management of a patient with 15q tetrasomy for dental treatment

Background and objectives

15q tetrasomy is a chromosomal abnormality that is a part of the heterogeneous group of extra structurally abnormal chromosomes. This syndrome is characterized by epilepsy, central hypotonia, developmental delay and intellectual disability, and autistic behavior. This is the first report of the anesthetic management of a patient with this syndrome.

Case report

We administered general anesthesia for dental treatment in a patient with 15q tetrasomy.

Conclusions

Appropriate planning for the prevention of complications such as seizures and hypotonia, and for delayed emergence from anesthesia, is required. Specifically, choosing short-acting drugs that do not induce seizures, together with suitable monitoring, resulted in successful anesthetic management of the patient with 15q tetrasomy.

Non-intubated thoracoscopic surgery: initial experience at a single center

Background

Non-intubated thoracoscopic surgery is an evolving form of minimally-invasive thoracic surgery. We commenced performing non-intubated thoracoscopic surgery at our center in August 2016. We would like to report our initial experience, over a period of 1 year, with this procedure.

Methods

From August 2016 to August 2017, non-intubated thoracoscopic surgery was performed in a series of consecutive patients who underwent thoracoscopic surgery in those who did not meet any of the following exclusion criteria: body mass index (BMI) >30, expected difficult airway, expected extensive pleural adhesion, severe cardiopulmonary dysfunction, persistent cough or excessive airway secretion, high risk of gastric reflux, and underlying neurological disorder.

Results

A total of 115 consecutive patients underwent non-intubated thoracoscopic surgery. Of these, 83 (72.2%) of patients had lung cancers that had undergone pulmonary resection and the other 32 (27.8%) patients were diagnosed with pulmonary metastasis, benign lung diseases, thymic tumor or other conditions. The mean time of anesthesia was 172.4 min and time of operation was 130 min. The mean postoperative chest tube duration was 3.9 days and time of hospital stay was 6.0 days. There were 9 conversions (7.8%) to intubation, due to increased respiratory movement with intraoperative hypoxemia or severe pleural adhesion. There were 16 complications (13.9%) following surgery, but all of these were successfully managed during the period of hospital stay. There was no postoperative mortality. In multivariate analysis, old age and high BMI were significant risk factors for conversion to intubation (hazard ratio =1.122, P=0.038; hazard ratio =1.408, P=0.042, respectively).

Conclusions

Non-intubated thoracoscopic surgery can safely be performed in selected patients.

Reclassifying Anaphylaxis to Neuromuscular Blocking Agents Based on the Presumed Patho-Mechanism: IgE-Mediated, Pharmacological Adverse Reaction or "Innate Hypersensitivity"?

Approximately 60% of perioperative anaphylactic reactions are thought to be immunoglobulin IgE mediated, whereas 40% are thought to be non-IgE mediated hypersensitivity reactions (both considered non-dose-related type B adverse drug reactions). In both cases, symptoms are elicited by mast cell degranulation. Also, pharmacological reactions to drugs (type A, dose-related) may sometimes mimic symptoms triggered by mast cell degranulation. In case of hypotension, bronchospasm, or urticarial rash due to mast cell degranulation, identification of the responsible mechanism is complicated. However, determination of the type of the underlying adverse drug reaction is of paramount interest for the decision of whether the culprit drug may be re-administered. Neuromuscular blocking agents (NMBA) are among the most frequent cause of perioperative anaphylaxis. Recently, it has been shown that NMBA may activate mast cells independently from IgE antibodies via the human Mas-related G-protein-coupled receptor member X2 (MRGPRX2). In light of this new insight into the patho-mechanism of pseudo-allergic adverse drug reactions, in which as drug-receptor interaction results in anaphylaxis like symptoms, we critically reviewed the literature on NMBA-induced perioperative anaphylaxis. We challenge the dogma that NMBA mainly cause IgE-mediated anaphylaxis via an IgE-mediated mechanism, which is based on studies that consider positive skin test to be specific for IgE-mediated hypersensitivity. Finally, we discuss the question whether MRGPRX2 mediated pseudo-allergic reactions should be re-classified as type A adverse reactions.

Use of neuromuscular blockers and neostigmine for general anesthesia and its association with neuraxial blockade: A retrospective study

This research aimed to assess the use of neuromuscular blockers (NMB) and its reversal, associated or not with neuraxial blockade, after general anesthesia.This retrospective study analyzed 1295 patients that underwent surgery with general anesthesia at Prof. Dr. José Aristodemo Pinotti Hospital in 2013. The study included patients aged >1 year, with complete, readable medical charts and anesthetic records.Rocuronium (ROC) was the most used NMB (96.7%), with an initial dose of 0.60 (0.52-0.74) mg/kg and total dose of 0.38 (0.27-0.53) mg/kg/h. In 24.3% of the cases, neuraxial blockade was associated with a significantly longer anesthesia (P < .001) than in cases without neuraxial block, regardless of technique (total intravenous (TIV) vs intravenous and inhalational (IV+IN)). In 71.9% of the cases, a single dose of NMB was used. Patients under TIV general anesthesia associated with neuraxial blockade had a lower total dose of ROC (mg/kg/h) in comparison with TIV GA alone (0.30 (0.23-0.39) and 0.42 (0.30-0.56) mg/kg/h, respectively, P < .001). The same was observed for patients under IV+IN GA (0.32 (0.23-0.41) and 0.43 (0.31-0.56) mg/kg/h, respectively, P < .001). The duration of anesthesia was longer according to increasing number of additional NMB doses (P < .001). Dose of neostigmine was 2.00 (2.00-2.00) mg or 29.41 (25.31-33.89) μg/kg. The interval between neostigmine and extubation was >30 minutes in 10.9% of cases.The most widely used NMB was ROC. Neuroaxial blockade (spinal or epidural) was significantly associated with reduced total dose of ROC (mg/kg/h) during general anesthesia, even in the absence of neuromuscular monitoring and regardless of general anesthetic technique chosen. In most cases, neostigmine was used to reverse neuromuscular block. The prolonged interval between neostigmine and extubation (>30 minutes) was neither associated with total doses of ROC or neostigmine, nor with the time of NMB administration. This study corroborates the important role of quantitative neuromuscular monitors and demonstrates that neuraxial blockade is associated with reduced total ROC dose. Further studies are needed to evaluate the possible role of neuraxial blockade in reducing the incidence of postoperative residual curarization.

[A rare complication of generalized tetanus: pulmonary embolism]

Le tétanos est une maladie caractérisée par une paralysie spastique et des spasmes. C’est une pathologie grave. Elle nécessite une prise en charge en milieu de réanimation. La mortalité est essentiellement liée aux complications neurovégétatives et infectieuses. Les complications thromboemboliques sont exceptionnelles au cours de cette maladie. A notre connaissance, l’embolie pulmonaire n’a jamais été rapportée et confirmée au cours du tétanos généralisé. Nous présentons à travers cette observation un cas de tétanos généralisé compliqué d’une embolie pulmonaire fibrino cruorique.

Neuronal Effects of Sugammadex in combination with Rocuronium or Vecuronium

Rocuronium (ROC) and Vecuronium (VEC) are the most currently used steroidal non-depolarizing neuromuscular blocking (MNB) agents. Sugammadex (SUG) rapidly reverses steroidal NMB agents after anaesthesia. The present study was conducted in order to evaluate neuronal effects of SUG alone and in combination with both ROC and VEC. Using MTT, CASP-3 activity and Western-blot we determined the toxicity of SUG, ROC or VEC in neurons in primary culture. SUG induces apoptosis/necrosis in neurons in primary culture and increases cytochrome C (CytC), apoptosis-inducing factor (AIF), Smac/Diablo and Caspase 3 (CASP-3) protein expression. Our results also demonstrated that both ROC and VEC prevent these SUG effects. The protective role of both ROC and VEC could be explained by the fact that SUG encapsulates NMB drugs. In BBB impaired conditions it would be desirable to control SUG doses to prevent the excess of free SUG in plasma that may induce neuronal damage. A balance between SUG, ROC or VEC would be necessary to prevent the risk of cell damage.

The Physiologically Difficult Airway

Airway management in critically ill patients involves the identification and management of the potentially difficult airway in order to avoid untoward complications. This focus on difficult airway management has traditionally referred to identifying anatomic characteristics of the patient that make either visualizing the glottic opening or placement of the tracheal tube through the vocal cords difficult. This paper will describe the physiologically difficult airway, in which physiologic derangements of the patient increase the risk of cardiovascular collapse from airway management. The four physiologically difficult airways described include hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure. The emergency physician should account for these physiologic derangements with airway management in critically ill patients regardless of the predicted anatomic difficulty of the intubation.

Impaired postural stability after laparoscopic surgery

BACKGROUND

Early postoperative mobilisation may reduce patient morbidity and improve hospital efficiency by accelerated discharge. The aim of this study was to measure postural stability early after laparoscopic surgery in order to assess how early it is safe to mobilise and discharge patients.

METHODS

We included 25 women undergoing outpatient gynaecological laparoscopic surgery in the study. Patients received standardised anaesthesia with propofol, remifentanil and rocuronium. Postural stability was assessed preoperatively, at 30 min after tracheal extubation, and at discharge from the post-anaesthesia care unit using a force platform where sway area, mean sway and sway velocity were determined. The assessments were done with eyes closed and with eyes open. The primary outcome was the change in sway area with eyes closed 30 min after extubation. Data are reported as median (25-75% range).

RESULTS

Three patients could not perform all the test's 30 min after extubation. Thirty minutes after extubation, sway area with eyes closed had increased significantly with 84 mm(2) (9-172, P = 0.011) and 108 mm(2) with eyes open (25-295, P = 0.0017). Median mean sway had also increased significantly 30 min postoperatively. No significant changes were found for sway velocity. We found no significant changes in mean sway, sway area or sway velocity at discharge from the post-anaesthesia care unit approximately 2 h after surgery.

CONCLUSION

Postural stability was significantly impaired 30 min after outpatient gynaecological laparoscopic surgery. However, the postural stability was normalised at discharge from the post-anaesthesia care unit 2 h after surgery.

Comparison of neostigmine induced reversal of vecuronium in normal weight, overweight and obese female patients

Background and Aims:

Obese patients are more vulnerable to residual neuromuscular block (NMB) and its associated complications in the post-operative period. This study was carried out to compare neostigmine induced reversal of vecuronium in normal weight, overweight and obese female patients, objectively using neuromuscular (NM) monitoring.

Methods:

Twenty female patients each belonging to normal weight, overweight and obese, based on body mass index, requiring general anaesthesia were recruited for this prospective cross sectional study. NMB was induced with vecuronium (0.1 mg/kg) dose based on patient's real body weight (RBW) and monitored using acceleromyographic train of four (TOF). All patients received neostigmine 40 μg/kg and glycopyrrolate 10 μg/kg at 25% of spontaneous recovery of first twitch height (T1) of TOF (DUR 25%) and were allowed to recover to TOF ratio of 0.9. Statistical analysis was done using analysis of variance test.

Results:

Recovery of TOF ratio to 0.5 was comparable in all three groups. Recovery of TOF ratio to 0.7 was delayed in obese (9.82 ± 3.21 min) compared with normal weight group (7.50 ± 2.52 min). Recovery of TOF to 0.9 was significantly delayed in both overweight (12.18 ± 4.29 min) and obese patients (13.78 ± 4.30 min). DUR 25% was significantly longer in overweight (mean, standard deviation [range]; 30.10 [19–40 min]) and obese (28.8 [12–45 min]) compared with normal weight patients (22.75 [16–30 min]).

Conclusion:

In overweight and obese patients, when vecuronium induction dose is based on RBW, neostigmine induced recovery of NMB is delayed in late phases (TOF 0.7-0.9), which may result in vulnerability for associated complications of incomplete recovery. Ensuring safe recovery thus requires objective NM monitoring.

3,16-Bisquaternary ammonium steroid derivatives as neuromuscular blocking agents: synthesis and biological evaluation

Neuromuscular blocking agents (NMBAs) are widely used in surgery to achieve skeleton muscles relaxation under light anesthesia status. In this work, we synthesized a series of 3,16-bisquaternary ammonium steroidal NMBAs. Among them, three compounds exhibited higher in vitro activities than the commenced drug rocuronium. In addition, structure-activity relationship was unveiled. We found that the intact acetylcholine-like moiety in D-ring was not necessary for maintaining activity but both the acetyl group and the quaternary nitrogen were very essential.

Survey of postoperative residual curarization, acute respiratory events and approach of anesthesiologists

BACKGROUND AND OBJECTIVES

residual paralysis following the use of neuromuscular blocking drugs (NMBDs) without neuromuscular monitoring remains a clinical problem, even when NMBDs are used. This study surveys postoperative residual curarization and critical respiratory events in the recovery room, as well as the clinical approach to PORC of anesthesiologists in our institution.

METHODS

This observational study included 415 patients who received general anesthesia with intermediate-acting NMBDs. Anesthesia was maintained by non-participating anesthesiologists who were blinded to the study. Neuromuscular monitoring was performed upon arrival in the recovery room. A CRE was defined as requiring airway support, peripheral oxygen saturation <90% and 90-93% despite receiving 3 L/min nasal O2, respiratory rate > 20 breaths/min, accessory muscle usage, difficulty with swallowing or speaking, and requiring reintubation. The clinical approach of our anesthesiologists toward reversal agents was examined using an 8-question mini-survey shortly after the study.

RESULTS

The incidence of PORC was 43% (n = 179) for TOFR < 0.9, and 15% (n = 61) for TOFR < 0.7. The incidence of TOFR < 0.9 was significantly higher in women, in those with ASA physical status 3, and with anesthesia of short duration (p < 0.05). In addition, 66% (n = 272) of the 415 patients arriving at the recovery room had received neostigmine. A TOFR < 0.9 was found in 46% (n = 126) of the patients receiving neostigmine.

CONCLUSIONS

When routine objective neuromuscular monitoring is not available, PORC remains a clinical problem despite the use of NMBDs. The timing and optimal antagonism of the neuromuscular blockade, and routine objective neuromuscular monitoring is recommended to enhance patient safety.

Residual neuromuscular blockade and postoperative critical respiratory events: literature review

AIMS AND OBJECTIVES

To investigate and synthesise published literature on the associations between residual neuromuscular blockade and critical respiratory events of postoperative adult patients in the postanaesthesia care unit.

BACKGROUND

Residual neuromuscular blockade continues to be common among patients transferred to the postanaesthesia care unit after general anaesthesia, while negative effects of residual neuromuscular blockade on respiratory function have been demonstrated in laboratory volunteers.

DESIGN

Literature review.

METHODS

Using key terms, a search was conducted in Cumulative Index for Nursing and Allied Health Literature, PubMed, Web of Science, Cochrane Database and EMBASE (January 1990-May 2013) for clinical trials or observational studies on the associations between residual neuromuscular blockade and critical respiratory events, published in English-language journals.

RESULTS

Nine articles met the inclusion criteria. Residual neuromuscular blockade definition threshold differed between studies. Among critical respiratory events, only hypoxaemia was investigated in all included studies. Residual neuromuscular blockade was significantly associated with increased incidence of hypoxaemia during postanaesthesia care unit stay in most studies, while associations with the rest of the critical respiratory events were inconclusive.

CONCLUSIONS

Although limited, existing research has provided evidence that patients with residual neuromuscular blockade are at high risk of early postoperative hypoxaemia. Further studies are needed to investigate independent associations between residual neuromuscular blockade and critical respiratory events, along with causality of these associations. The clinical importance of residual neuromuscular blockade for groups at high risk of critical respiratory events should also be investigated.

RELEVANCE TO CLINICAL PRACTICE

Healthcare professionals have to be aware of the increased risk of hypoxaemia in patients with residual neuromuscular blockade. Efforts to decrease residual neuromuscular blockade incidence, combined with identification and appropriate evaluation of patients with residual neuromuscular blockade during postanaesthesia care unit stay, are recommended.

Sugammadex, a neuromuscular blockade reversal agent, causes neuronal apoptosis in primary cultures

Sugammadex, a γ-cyclodextrin that encapsulates selectively steroidal neuromuscular blocking agents, such as rocuronium or vecuronium, has changed the face of clinical neuromuscular pharmacology. Sugammadex allows a rapid reversal of muscle paralysis. Sugammadex appears to be safe and well tolerated. Its blood-brain barrier penetration is poor (< 3% in rats), and thus no relevant central nervous toxicity is expected. However the blood brain barrier permeability can be altered under different conditions (i.e. neurodegenerative diseases, trauma, ischemia, infections, or immature nervous system). Using MTT, confocal microscopy, caspase-3 activity, cholesterol quantification and Western-blot we determine toxicity of Sugammadex in neurons in primary culture. Here we show that clinically relevant sugammadex concentrations cause apoptotic/necrosis neuron death in primary cultures. Studies on the underlying mechanism revealed that sugammadex-induced activation of mitochondria-dependent apoptosis associates with depletion of neuronal cholesterol levels. Furthermore SUG increase CytC, AIF, Smac/Diablo and CASP-3 protein expression in cells in culture. Potential association of SUG-induced alteration in cholesterol homeostasis with oxidative stress and apoptosis activation occurs. Furthermore, resistance/sensitivity to oxidative stress differs between neuronal cell types.

Residual neuromuscular blockade in critical care

Neuromuscular blockade is a pharmacological adjunct for anesthesia and for surgical interventions. Neuromuscular blockers can facilitate ease of instrumentation and reduce complications associated with intubation. An undesirable sequela of these agents is residual neuromuscular blockade. Residual neuromuscular blockade is linked to aspiration, diminished response to hypoxia, and obstruction of the upper airway that may occur soon after extubation. If an operation is particularly complex or requires a long anesthesia time, residual neuromuscular blockade can contribute to longer stays in the intensive care unit and more hours of mechanical ventilation. Given the risks of this medication class, it is essential to have an understanding of the mechanism of action of, assessment of, and factors affecting blockade and to be able to identify factors that affect pharmacokinetics.

Anaphyllaxis management: Current concepts

Anaphylactic shock is medical emergency characterized by circulatory collapse resulted from severe acute allergic reactions, namely anaphylaxis and anaphylactoid reaction. Anaphylaxis is an acute, systemic, IgE-mediated, and immediate hypersensitivity reaction caused by the release of mediators by mast cells and basophils after exposure to antigens. The pathophysiology involves activated mast cells and basophils releasing preformed, granule-associated mediators, and newly formed lipid mediators, as well as generating cytokines and chemokines. These cause vasodilatation, increased capillary permeability, and smooth muscle contraction, and attract new cells to the area. Positive feedback mechanisms amplify the reaction, although conversely reactions can self-limit. Anaphylaxis is a clinical diagnosis with a combinations of symptoms and signs that include weakness, dizziness, flushing, angioedema, urticaria of the skin, congestion, and sneezing. More severe symptoms include bronchial constriction, hypotension, vascular collapse associated with angioedema and urticaria, gastrointestinal distress, cardiovascular arrhythmias, and arrest. Prompt administration of epinephrine is critical for the success in the treatment of acute anaphylaxis.

Neuromuscular blocking agents for electroconvulsive therapy: a systematic review

Electroconvulsive therapy (ECT) is the transcutaneous application of small electrical stimuli to the brain to induce generalised seizures for the treatment of selected psychiatric disorders. The clinical indications for ECT as an effective therapeutic modality have been considerably expanded since its introduction. Anaesthesia and neuromuscular blocking agents (NMBAs) are required to ensure patients' safety during ECT. The optimal dose of muscle relaxant for ECT reduces muscle contractions without inducing complete paralysis. Slight residual motor convulsive activity is helpful in ascertaining that a seizure has occurred, while total paralysis prolongs the procedure unnecessarily. Suxamethonium is commonly used, but nondepolarising NMBAs are indicated in patients with certain comorbidities. In this review, we summarise current concepts of NMBA management for ECT.

Successful use of Rocuronium and Sugammadex in an Anticipated Difficult Airway Scenario

Neuromuscular blocking agents are often avoided in anticipated difficult airway scenarios. However, to facilitate jet ventilation, muscle relaxants are useful. We report a case of a potentially threatened airway in a 21-year-old with a large infraglottic pedunculated polyp. In this case rocuronium was used on induction to facilitate subsequent jet ventilation and periglottic laser ablation of the tumour. As the duration of the surgery was not predictable, the intention was to use sugammadex at the end to ensure complete reversal of muscle relaxation. This strategy also provided a quick rescue option if there was a sudden loss of the airway.

Anaesthesia for the patient with dementia undergoing outpatient surgery

PURPOSE OF REVIEW

Dementia is common in elderly patients, and anaesthesiologists are increasingly challenged in managing these patients who are especially vulnerable. The aim of this article is to highlight some of the most important perioperative issues relating to demented patients, both regarding anaesthesia and other aspects that should be considered to ensure a quick and uncomplicated recovery.

RECENT FINDINGS

Demented patients often receive prescribed medication that can interact with various anaesthetic drugs and cause serious side effects. The anaesthesiologist should consider this when choosing the drugs used during surgery and when relieving postoperative pain. Generally, hypnotics, opioids, and inhalational anaesthetics should be administered in lower doses and carefully titrated because of altered pharmacokinetics and pharmacodynamics leading to a great variability, as documented in elderly patients. Neuromuscular blocking agents, and especially rocuronium, display an increased variability in the duration of action, but the new drug sugammadex may reverse the neuromuscular block in a few minutes. Postoperative cognitive decline is more frequent in elderly patients with preexisting cognitive impairment and several preventive measurements can be provided.

SUMMARY

Outpatient surgery for demented patients causes many concerns in relation to anaesthesia. Extensive drug-related problems may arise and restrictive drug usage is recommended to avoid serious complications.

[Sugammadex, a novel drug for neuromuscular blockade reversal]

Significant progress in the management of aminosteroid nondepolarizing neuromuscular blockers will follow the introduction of sugammadex (Org 25969). Safety and rapid recovery of muscle force will improve and the adverse effects of acetylcholinesterase inhibitors will be avoided. Sugammadex is a modified gamma-cyclodextrin agent developed for the specific reversal of rocuronium and, to a lesser extent, vecuronium. This novel drug functions by means of encapsulation (chelation). Sugammadex was recently approved by the European Medicines Evaluation Agency and became available in Spain in 2009, leading to a series of changes related to patient safety and surgical conditions. We review the literature on sugammadex published to date.