Butyrylcholinesterase deficiency and its clinical importance in anaesthesia: a systematic review

The Potential Risk of Reduced Serum Cholinesterase Activity in COVID-19 Patients Suffering From Cytokine Storm

Background and objective Several blood biochemical parameters are used to biomonitor coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Reduced serum cholinesterase (ChE) has been suggested to be a predictive indicator of the severity and outcome of COVID-19 infection. This study aimed to examine serum ChE activity in hospitalized and terminally ill COVID-19 patients with cytokine storm and evaluate the enzyme for the in vitro ChE-inhibitory activity of the organophosphate dichlorvos. Methods We determined the serum ChE activity, electrometrically, among hospitalized COVID-19-cytokine storm patients and their non-cytokine storm counterparts. Aliquots of serum samples from healthy volunteers, COVID-19-cytokine storm patients, and non-cytokine storm COVID-19 patients were pooled separately. They were incubated in vitro for 10 minutes with dichlorvos at 0.25 or 0.5 μM. Serum samples from the three groups were subjected to ChE inhibition temporally (5-60 minutes) by 0.25 μM dichlorvos to evaluate the kinetics of enzyme inhibition using steady-state kinetics. Results Of the 165 hospitalized patients with COVID-19, 33 (20%) suffered from the cytokine storm. Serum ChE activity of female COVID-19 patients with cytokine storm was significantly lower than that of the non-cytokine storm counterparts. Risk analysis of reduced serum ChE activity (≥20%) among the 33 COVID-19 patients with cytokine storm compared to 111 non-cytokine storm COVID-19 patients revealed that the former were significantly at risk of reduced enzyme activity. In vitro, dichlorvos at 0.25 μM and 0.5 μM significantly inhibited serum ChE activity in all the groups. The COVID-19-cytokine storm group was the least affected. Dichlorvos at 0.25 μM progressively (5-60 minutes) inhibited serum ChE activity. The inhibition kinetic parameters in COVID-19-cytokine storm patients showed a decrease in the half-life of inhibition (14.54%), inhibition rate (51.46%), and total inhibition time (14.55%). Conclusions Reduced serum ChE in COVID-19 patients with cytokine storm could be adopted as a potential additional laboratory examination tool for bedside risk assessment. The in vitro inhibition profile of serum ChE activity by dichlorvos in COVID-19-cytokine storm patients suggests reduced susceptibility of the enzyme to inhibition. The response of COVID-19 patients to ChE-inhibiting medications should be cautiously evaluated with prior in vitro tests.

Emerging significance of butyrylcholinesterase

Butyrylcholinesterase (BChE; EC 3.1.1.8), an enzyme structurally related to acetylcholinesterase, is widely distributed in the human body. It plays a role in the detoxification of chemicals such as succinylcholine, a muscle relaxant used in anesthetic practice. BChE is well-known due to variant forms of the enzyme with little or no hydrolytic activity which exist in some endogamous communities and result in prolonged apnea following the administration of succinylcholine. Its other functions include the ability to hydrolyze acetylcholine, the cholinergic neurotransmitter in the brain, when its primary hydrolytic enzyme, acetylcholinesterase, is absent. To assess its potential roles, BChE was studied in relation to insulin resistance, type 2 diabetes mellitus, cognition, hepatic disorders, cardiovascular and cerebrovascular diseases, and inflammatory conditions. Individuals who lack the enzyme activity of BChE are otherwise healthy, until they are given drugs hydrolyzed by this enzyme. Therefore, BChE is a candidate for the study of loss-of-function mutations in humans. Studying individuals with variant forms of BChE can provide insights into whether they are protected against metabolic diseases. The potential utility of the enzyme as a biomarker for Alzheimer's disease and the response to its drug treatment can also be assessed.

A novel near-infrared fluorescent probe for high-sensitivity detection of butyrylcholinesterase in various pathological states

Butyrylcholinesterase (BChE) is a crucial hydrolytic enzyme predominantly synthesized in the liver, playing a significant role in conditions like liver disorders, diabetes, Alzheimer's disease, and fat metabolism regulation. This study aims to address the current limitations in visualizing BChE activity in diseases at various states by introducing an ultra-sensitive near-infrared fluorescent probe, FDCM-BChE. The probe was engineered to have several properties, such as a large Stokes shift, rapid response time, high stability, excellent selectivity, and low detection limits. We validated the efficacy of FDCM-BChE in quantifying BChE activity in human serum and leveraged its low cytotoxicity for cellular imaging. The study revealed the downregulation of BChE activity in liver cancer and hepatic injury and the upregulation in diabetes. Thus, FDCM-BChE shows promise as a tool for specific applications, providing insights into diseases associated with BChE activity.

The First-Known Case of Hereditary Heterozygous Butyrylcholinesterase Deficiency in a Patient on Dialysis

Serum levels of butyrylcholinesterase (BChE) are commonly used to assess liver function. Its levels have been reported to be significantly lower in patients undergoing dialysis. To the best of our knowledge, this is the first report of hereditary heterozygous BChE deficiency in a patient undergoing dialysis. Medical staff involved in the care of patients with BChE deficiency should be aware of anesthetic usage, because prolonged neuromuscular paralysis following the administration of succinylcholine or mivacurium may occur. However, in the heterozygotes, BChE activity is not completely absent. Therefore, differentiating patients undergoing dialysis is challenging. A 52-year-old man underwent living-related kidney transplantation for focal segmental glomerulosclerosis at 22 years of age. As the renal function gradually worsened, the patient began to receive combined hemodialysis and peritoneal dialysis therapy. No problems with anesthesia were observed in past surgeries. The patient's BChE levels fluctuated between 76 and 170 U/L (reference range: 198-495 U/L); however, they had never been previously investigated. We suspected hereditary heterozygous BChE deficiency because the patient's sister was also diagnosed with it. DNA sequencing revealed a heterozygous missense mutation (Gly365Arg) and a K-variant (Ala539Thr). Patients on dialysis with low serum BChE levels often present with low albumin levels which may be overlooked as malnutrition. Thus, BChE deficiency should be suspected in patients on dialysis with unexplained low serum BChE levels. In the case of heterozygous BChE deficiency, the reference value is low, and continuous monitoring is crucial.

Drug and pro-drug substrates and pseudo-substrates of human butyrylcholinesterase

Butyrylcholinesterase (BChE) is present in plasma and numerous cells and organs. Its physiological function(s) is(are) still unclear. However, this enzyme is of pharmacological and toxicological importance. It displays a broad specificity and is capable of hydrolyzing a wide range of substrates with turnovers differing by several orders of magnitude. Nowaday, these substrates include more than two dozen carboxyl-ester drugs, numerous acetylated prodrugs, and transition state analogues of acetylcholine. In addition, BChE displays a promiscuous hydrolytic activity toward amide bonds of arylacylamides, and slowly hydrolyzes carbamyl- and phosphoryl-esters. Certain pseudo-substrates like carbamates and organophosphates are major drugs of potential medical interest. The existence of a large genetic poly-allelism, affecting the catalytic properties of BChE is at the origin of clinical complications in the use of certain drugs catabolized by BChE. The number of drugs and prodrugs hydrolyzed by BChE is expected to increase in the future. However, very few quantitative data (Km, kcat) are available for most marketed drugs, and except for myorelaxants like succinylcholine and mivacurium, the impact of BChE genetic mutations on catalytic parameters has not been evaluated for most of these drugs.

Clinical and demographic factors affecting trough levels of isavuconazole in critically ill patients with or without COVID-19

BACKGROUND

The broad-spectrum antifungal isavuconazole is administered to treat invasive aspergillosis and mucormycosis.

OBJECTIVES

Isavuconazole plasma concentrations in critically ill ICU patients with or without COVID-19 and invasive fungal infection were determined, and factors for sub-therapeutic drug levels (<1 μg/mL) were evaluated.

PATIENTS AND METHODS

Isavuconazole plasma levels were measured as part of therapeutic drug monitoring (TDM) in ICUs of a tertiary hospital. Concentrations determined 20-28 h after previous dosing were defined as trough (Cmin ) levels. A total of 160 Cmin levels from 62 patients with invasive fungal infections were analysed, 30 of which suffering from COVID-19. Patient characteristics included into univariable and multivariable analyses were gender, age, COVID-19 status, body mass index (BMI), sepsis-related organ failure (SOFA) score, renal replacement therapy (RRT) and extracorporeal membrane oxygenation (ECMO) requirement.

RESULTS

The mean Cmin of isavuconazole in all patients was 1.64 μg/mL (interquartile range 0.83-2.24 μg/mL, total range 0.24-5.67 μg/mL). In total, 34.4% of the Cmin values (corresponding to 46.8% of patients) were below a threshold concentration of 1 μg/mL. Drug concentrations between patients with or without COVID-19 did not differ (p = .43). In contrast, levels were significantly lower in patients with female sex (p = .0007), age ≤ 65 years (p = .002), BMI > 25 (p = .006), SOFA score > 12 (p = .026), RRT (p = .017) and ECMO requirement (p = .001).

CONCLUSIONS

Isavuconazole plasma levels can be negatively affected by patients' risk factors, supportive renal replacement and ECMO therapy. Future prospective studies analysing the relevance of isavuconazole drug levels in ICU patient outcome are urgently needed.

Customized fluorescent probe for peering into the expression of butyrylcholinesterase in thyroid cancer

BACKGROUND

Thyroid cancer has been increasingly prevalent in recent years. The main diagnostic methods for thyroid are B-ultrasound scan, serum detection and puncture detection. However, these methods are invasive and complex. It is a pressing need to develop non-invasive or minimally invasive methods for thyroid cancer diagnosis. Fluorescence method as a non-invasive detection method has attracted much attention. Butyrylcholinesterase (BChE) is a common enzyme in the human body, and many diseases affect its reduction. We found that BChE is also a marker for thyroid cancer. Therefore, it is of certain clinical value to explore the expression of BChE in thyroid cancer cells through a customized fluorescent probe to provide valuable experimental data and clues for studying the expression of thyroid cancer marker to reflect thyroid status.

RESULTS

In this study, we customized a fluorescent probe named Kang-BChE, which is easy to synthesize with a high yield. The experimental results show that the probe Kang-BChE can detect BChE in the linear range of 0-900 U L-1 (R2 = 0.9963), and the detection limit is as low as 3.93 U L-1 (λex/em = 550/689 nm). In addition, Kang-BChE probes have low cytotoxicity, good specificity, and can completely eliminate interference from acetylcholinesterase (AChE). Kang-BChE showed excellent stability in the detection of complex biological samples in serum recovery experiments (95.64-103.12 %). This study was the first time using Kang-BChE to study the low expression of BChE in thyroid cancer cells (Tpc-1 cells). In addition, we observed that H2O2 concentration in Tpc-1 cells was positively correlated with BChE activity.

SIGNIFICANCE

Kang-BChE is expected to be an important tool for monitoring the change of BChE content in complex biological environments due to its excellent performance. Kang-BChE can also be used to explore the influence of molecules in more organisms on the change of BChE content due to its excellent anti-interference ability. We expect that Kang-BChE can play a significant role in the clinical diagnosis and treatment of thyroid cancer.

Association of Reduced Maternal Plasma Cholinesterase Activity With Preeclampsia: A Meta-Analysis

Blood butyrylcholinesterase (BChE) activity has been found to decrease during pregnancy and reportedly decrease even more in preeclampsia (PE). The purpose of the present meta-analysis was to answer a specific question of whether BChE activity (in the plasma, serum, or whole blood) is reduced in pregnant women suffering from PE compared to those with normal pregnancy. The meta-analysis included 15 studies with 20 records of BChE activity in 608 women compared to 569 healthy pregnant (control) ones. The studies were subjected to quality assessment using the Newcastle-Ottawa Scale (NOS). Using the Meta-Essentials software program 1.5, the one-group random effects model and forest plot revealed that the percentage of BChE activity in pregnant women with PE was 84.84% of the control value, with a standard error of 4.09 and 95% C.I. of 76.28, 93.41, indicating a significant 15.16% reduction in BChE activity in comparison to healthy pregnancy. No significant heterogeneity was seen in the analyzed data and the funnel plot did show publication bias. Subgroup (mild, severe, and unclassified PE) forest plot analysis revealed that the % BChE activities in PE compared to respective healthy pregnancies were 96.28%, 97.08%, and 76.62%, respectively with no heterogeneity. The median NOS score of the 15 studies included in the meta-analysis was 7, ranging from 5 to 8 (medium to high quality), and the forest plot showed an effect size of 0.735. This meta-analysis shows that BChE activity is reduced in PE compared with normal pregnancy and its value as a biomarker warrants further clinical studies.

Neuromuscular Blockade Monitoring: Having It but Knowing When Not to Trust It

Butyrylcholinesterase (BChE) is an enzyme involved in the degradation of depolarizing and non-depolarizing neuromuscular blocking agents (NMBA), such as succinylcholine and mivacurium, respectively. Its deficiency is inherited or acquired, and results in paralysis of skeletal muscles after NMBA administration. We report a case of a 32-year-old pregnant woman proposed for cesarean section. General anesthesia (GA) was induced using propofol and succinylcholine. The surgical procedure was uneventful but after 40 minutes, there was no reversal of neuromuscular block (NMB). Other differential diagnoses were excluded and a deficit of BChe was assumed. When the train-of-four ratio (TOFr) achieved 40%, neostigmine/atropine led to the slow recovery of NMB up to TOFr 88%. The patient was extubated, but ventilation proved ineffective, so GA was induced and the patient was reintubated. A new measurement found a TOFr of 60%. Sedation and ventilatory support were maintained until the complete reversal of NMB (4 hours after succinylcholine). Prolonged block is a rare but serious complication of the use of succinylcholine in patients with BChE deficiency. This report not only highlights the importance of intraoperative NMB monitoring in homozygotic patients for atypical cholinesterase but also raises awareness for its careful interpretation.

General Anesthetic Care of Obese Patients Undergoing Surgery: A Review of Current Anesthetic Considerations and Recent Advances

Obesity has long been linked to adverse health effects over time. As the prevalence of obesity continues to rise, it is important to anticipate and minimize the complications that obesity brings in the anesthesia setting during surgery. Anesthetic departments must recognize the innumerable risks when managing patients with obesity undergoing surgery, including anatomical and physiological changes as well as comorbidities such as diabetes, cardiovascular diseases, and malignancies. Therefore, the purpose of this review is to analyze the current literature and evaluate the current and recent advances in anesthetic care of obese patients undergoing surgery, to better understand the specific challenges this patient population faces. A greater understanding of the differences between anesthetic care for obese patients can help to improve patient care and the specificity of treatment. The examination of the literature will focus on differing patient outcomes and safety precautions in obese patients as compared to the general population. Specifically highlighting the differences in pre-operative, intra-operative, and post-operative care, with the aim to identify issues and present possible solutions.

[Trigger-free anesthesia : Indications and safe application]

The safe anesthesiological care of patients with neuromuscular diseases poses a particular challenge for anesthetists. Only a small group of muscle diseases and syndromes are associated with an increased risk of malignant hyperthermia and therefore require trigger-free anesthetic procedures avoiding volatile anesthetics and succinylcholine. These diseases are frequently associated with mutations in the RYR1, CACNA1S or STAC-3 genes. In other neuromuscular diseases, anesthetic-induced rhabdomyolysis can occur. Therefore, volatile anesthetics should be avoided in these patients in addition to the contraindication for succinylcholine. In other neuromuscular diseases the risk of a propofol infusion syndrome or myotonic crises can be elevated or the duration of the effect of non-depolarizing muscle relaxants can be changed in an incalculable way. In every case an individual anesthetic aproach including the avoidance of potential pharmacological or non-pharmacological triggers is essential for the safety of the patients.

Albumin Is a Component of the Esterase Status of Human Blood Plasma

The esterase status of blood plasma can claim to be one of the universal markers of various diseases; therefore, it deserves attention when searching for markers of the severity of COVID-19 and other infectious and non-infectious pathologies. When analyzing the esterase status of blood plasma, the esterase activity of serum albumin, which is the major protein in the blood of mammals, should not be ignored. The purpose of this study is to expand understanding of the esterase status of blood plasma and to evaluate the relationship of the esterase status, which includes information on the amount and enzymatic activity of human serum albumin (HSA), with other biochemical parameters of human blood, using the example of surviving and deceased patients with confirmed COVID-19. In experiments in vitro and in silico, the activity of human plasma and pure HSA towards various substrates was studied, and the effect of various inhibitors on this activity was tested. Then, a comparative analysis of the esterase status and a number of basic biochemical parameters of the blood plasma of healthy subjects and patients with confirmed COVID-19 was performed. Statistically significant differences have been found in esterase status and biochemical indices (including albumin levels) between healthy subjects and patients with COVID-19, as well as between surviving and deceased patients. Additional evidence has been obtained for the importance of albumin as a diagnostic marker. Of particular interest is a new index, [Urea] × [MDA] × 1000/(BChEb × [ALB]), which in the group of deceased patients was 10 times higher than in the group of survivors and 26 times higher than the value in the group of apparently healthy elderly subjects.

Organophosphorus Poisoning: Acute Respiratory Distress Syndrome (ARDS) and Cardiac Failure as Cause of Death in Hospitalized Patients

Industrial production of food for animals and humans needs increasing amounts of pesticides, especially of organophosphates, which are now easily available worldwide. More than 3 million cases of acute severe poisoning are estimated to occur worldwide every year, and even more cases remain unreported, while 200,000–350,000 incidentally or intentionally poisoned people die every year. Diagnostic and therapeutic procedures in organophosphate poisoning have, however, remained unchanged. In addition to several neurologic symptoms (miosis, fasciculations), hypersecretion of salivary, bronchial, and sweat glands, vomiting, diarrhea, and loss of urine rapidly induce dehydration, hypovolemia, loss of conscience and respiratory distress. Within hours, signs of acidosis due to systemic hypoxia can be observed at first laboratory investigation after hospitalization. While determination of serum-cholinesterase does not have any diagnostic value, it has been established that hypoalbuminemia alone or accompanied by an increase in creatinine, lactate, or C-reactive protein serum levels has negative prognostic value. Increased serum levels of C-reactive protein are a sign of systemic ischemia. Protective mechanical ventilation should be avoided, if possible. In fact, acute respiratory distress syndrome characterized by congestion and increased weight of the lung, accompanied by heart failure, may become the cause of death. As the excess of acetylcholine at the neuronal level can persist for weeks until enough newly, locally synthesized acetylcholinesterase becomes available (the value of oximes in reducing this time is still under debate), after atropine administration, intravenous albumin and fluid infusion should be the first therapeutic interventions to reestablish normal blood volume and normal tissue oxygenation, avoiding death by cardiac arrest.

Comparison of 3 Rates for the Continuous Infusion of Mivacurium During Ambulatory Vitreoretinal Surgery Under General Anesthesia: A Prospective, Randomized, Controlled Clinical Trial

Purpose

Mivacurium, the shortest-acting benzylisoquinoline nondepolarizing neuromuscular blocker used in clinical practice, is suitable for short-term ambulatory operations under general anesthesia. We investigated the neuromuscular blockade effect of different maintenance doses of mivacurium during ambulatory vitreoretinal surgery under general anesthesia and tried to determine the appropriate maintenance dose.

Patients and Methods

Ninety-nine patients undergoing general anesthesia for elective ambulatory vitreoretinal surgery were randomly divided into three groups using the random number table method. Patients received three maintenance doses of mivacurium during surgery as follows: 3 μg/(kg·min) in group M1 (n = 33), 6 μg/(kg·min) in group M2 (n = 33), and 9 μg/(kg·min) in group M3 (n = 33). The primary outcome was the time from mivacurium withdrawal to a train-of-four stimulation ratio (TOFr) ≥ 0.9, and the secondary outcomes were the time from mivacurium withdrawal to TOFr ≥ 0.7, extubation time, incidence of TOFr < 0.9 after surgery and neuromuscular block effect.

Results

The time from mivacurium withdrawal to TOFr ≥ 0.9 and to TOFr ≥ 0.7 was significantly longer in group M3 than in groups M1 and M2 (25.6±7.2 min vs 16.4±5.9 min and 18.6±5.3 min, P < 0.001; 22.1±6.3 min vs 13.6 ± 5.8 min and 15.5 ± 4.8 min; P < 0.001, respectively). There was a significant difference in the extubation time, the incidence of TOFr < 0.9 during extubation and upon leaving the operating room between group M3 and group M1 (all P < 0.05), but there was no such significant difference between group M2 and group M1 (all P > 0.05). The intraoperative depth of neuromuscular blockade in the three groups was significantly different, with 69.7% shallow block in group M1, 75.8% moderate block in group M2 and 63.6% deep block in group M3 (P < 0.001). One patient in group M1 experienced slight body movement during the operation.

Conclusion

An intraoperative continuous infusion of 6 μg/(kg·min) mivacurium can not only achieve good postoperative recovery but also provide a satisfactory neuromuscular blockade effect during surgery, and this maintenance dose is suitable for neuromuscular blockade during ambulatory vitreoretinal surgery.

Risk Assessment of Electroconvulsive Therapy in Clinical Routine: A 3-Year Analysis of Life-Threatening Events in More Than 3,000 Treatment Sessions

Background: Extensive research has reported that electroconvulsive therapy (ECT) can be highly effective in approximately 80% of patients suffering from depression. Its clinical use is mainly limited by historical objections and the concern about unwanted adverse effects (AEs), including serious and potentially life-threatening adverse events (pLTAEs), induced either by ECT or by anesthesia. Objective risk estimation is, therefore, a decisive factor in determining an indication for ECT. Methods: This paper presents a retrospective analysis of 3-year safety protocols and patient files of 157 patients who received a total of 3,106 ECT applications in a psychiatric inpatient setting at a psychiatric community hospital. This patient group comprises 5.3% of inpatients admitted with comparable diagnoses. Adverse events were analyzed from standardized safety protocols and patient files with a focus on pLTAEs. Results: Adverse events were reported for 30 (19.1%) of the 157 participants during 39 (6.1%) of 641 hospital stays. Serious pLTAEs occurred during three electroconvulsive stimulations in three patients, who needed action through the administration of medication or mechanical respiration. No patient suffered permanent damage to health, and no patient died. The incidence of these and other AEs was independent of sex, age, and diagnosis of patients, and anesthesia medication. Minor AEs occurred more often with higher stimulus doses and an increasing number of treatments. Conclusion: The low incidence rate of 0.097% of serious pLTAEs that require medical action may allow the conclusion that ECT is a rather safe treatment when performed in a controlled setting. The beneficial risk profile of ECT performed in the standard care of psychiatric hospitals suggests a more generous indication of this treatment method. We recommend that ECT facilities collect individual safety data to allow a reliable judgment of their institutional ECT risk profile.

Cholinesterase activity in serum during general anesthesia in patients with or without vascular disease

Maintaining hemodynamic stability during the induction and maintenance of anesthesia is one of the challenges of the anesthesiologist. Patients with vascular disease are at increased risk of instability due to imbalance between the sympathetic and parasympathetic parts of the autonomic nervous system, a balance accessible by serum cholinesterase activity. We aim to characterize the dynamics of cholinesterase activity in patients undergoing general anesthesia (GA) and surgery. This was a prospective study of 57 patients undergoing ambulatory or vascular surgery under GA. Cholinesterase activity was measured before the induction of anesthesia, after 15 min and at the end of surgery by calculating the capacity of serum acetylcholinesterase (AChE) and butyrylcholinesterase to hydrolyze AcetylThioCholine. Data on atherosclerotic disease, anesthesia management were analyzed. Both AChE and total cholinergic status (CS) decreased significantly after GA induction at 15 min and even more so by the end of surgery. Vascular surgery patients had lower baseline cholinesterase activity compared to ambulatory surgery patients. Patients requiring intraoperative administration of phenylephrine for hemodynamic support (21.1%) had a significantly lower level of AChE and CS compared to untreated patients. Our findings serve as a mirror to the sympathetic/parasympathetic imbalance during GA, with a marked decrease in the parasympathetic tone. The data of a subgroup analysis show a correlation between low cholinesterase activity and an increase in the need for hemodynamic support.

Timing of blood sampling for butyrylcholinesterase phenotyping in patients with prolonged neuromuscular block after mivacurium or suxamethonium

INTRODUCTION

Variants of butyrylcholinesterase are frequently associated with prolonged response to suxamethonium or mivacurium. Butyrylcholinesterase (BChE) can be characterized by phenotyping and determination of genotype. Inappropriate timing of blood sampling might interfere with phenotyping methods. However, guidelines regarding delay between exposure to anaesthesia and testing are not clearly defined. In this study, the BChE activity and phenotype in an early (T1) and late (T2) phase were compared and the phenotype/genotype correlation was assessed.

METHODS

Patients with a prolonged paralysis after mivacurium or suxamethonium were selected after ethical committee approval and written consent. BChE activity was based on butyrylthiocholine hydrolysis rate and phenotyping on differential inhibition of BChE activity with dibucaine and fluoride. DNA sequencing allowed genotypic characterization.

RESULTS

We included the results of 20 patients with prolonged neuromuscular block (NMB) induced by mivacurium or suxamethonium. In these patients, BChE activity was different at T1 and T2 (2120 [1506-2733] U L^-1 and 4055 [2810-5301] U L^-1 , respectively; P = 0.0014; values are mean [95% CI]). When phenotyping was possible, phenotyping at T1 and T2 yielded identical results. Phenotyping failed to identify one new variant (p.Tyr146Cys) and the K variant in 14 of 16 patients.

CONCLUSION

Anaesthesia interfered with BChE activity, but not with phenotyping. Phenotyping can be performed on blood drawn during or immediately after recovery of mivacurium or suxamethonium to screen for clinically relevant variants of BChE. However, accurate diagnosis of BChE deficiency needs further confirmation by determination of genotype.

In Situ Generation of Prussian Blue by MIL-53 (Fe) for Point-of-Care Testing of Butyrylcholinesterase Activity Using a Portable High-Throughput Photothermal Device

Butyrylcholinesterase (BuChE), the primary source of serum cholinesterase activity, is an indispensable biochemical marker for clinical diagnosis of liver function and organophosphorus poisoning. The requirement for bulky and expensive instruments represents a huge hindrance for point-of-care testing (POCT) of BuChE, especially in resource-limited settings. Herein, an easy-operated, economic, and portable photothermal (PT) biosensing platform for high-throughput BuChE detection was rationally designed. BuChE could "light up" the PT signal through in situ generation of Prussian blue (PB) by MIL-53 (Fe), which allowed us to translate biological signals into temperature signals. Such temperature change signals could be monitored at high throughput (six samples for a single measurement) by a miniature self-made integrated PT device via combining separable 96-well plates, a three-dimensional (3D) printed sample bracket, 808 nm lasers, and thermometers, satisfying the requirement for rapid on-site detection in a large batch with low cost. In addition, the large specific surface area, 3D network structure, and high porosity of MIL-53 (Fe) offered a beneficial platform for its reaction with enzymatic hydrolysate, resulting in high sensing sensitivity and low detection limit (0.3 U L^-1), which was at least 20 000 times lower than the normal human serum BuChE activity. This facile, affordable, and broad applicability PT sensing platform provides a beneficial reference for the rational design of other disease diagnostic approaches suitable for POCT.

Structure and therapeutic uses of butyrylcholinesterase: Application in detoxification, Alzheimer's disease, and fat metabolism

Structural information of butyrylcholinesterase (BChE) and its variants associated with several diseases are discussed here. Pure human BChE has been proved safe and effective in treating organophosphorus (OPs) poisoning and has completed Phase 1 and 2 pharmacokinetic (PK) and safety studies. The introduction of specific mutations into native BChE to endow it a self-reactivating property has gained much progress in producing effective OPs hydrolases. The hydrolysis ability of native BChE on cocaine has been confirmed but was blocked to clinical application due to poor PK properties. Several BChE mutants with elevated cocaine hydrolysis activity were published, some of which have shown safety and efficiency in treating cocaine addiction of human. The increased level of BChE in progressed Alzheimer's disease patients made it a promising target to elevate acetylcholine level and attenuate cognitive status. A variety of selective BChE inhibitors with high inhibitory activity published in recent years are reviewed here. BChE could influence the weight and insulin secretion and resistance of BChE knockout (KO) mice through hydrolyzing ghrelin. The BChE-ghrelin pathway could also regulate aggressive behaviors of BChE-KO mice.

Break the Spasm with Succinylcholine, but Risk Intraoperative Awareness with Undiagnosed Pseudocholinesterase Deficiency

Succinylcholine is a commonly used medication in all aspects of anesthetic care, and there are a number of known side effects and complications associated with its use. However, when succinylcholine is used emergently, anesthesia providers must remain vigilant to undiagnosed conditions that pose additional risks to patients. We report the use of succinylcholine to treat acute, refractory laryngospasm after extubation leading to prolonged neuromuscular paralysis. There are unique challenges presented by this case including the risk of anesthesia awareness with recall due to the cognitive biases that prevent the clinical diagnosis of pseudocholinesterase deficiency.

Pseudocholinesterase Deficiency - Is Succinylcholine Still Needed to Facilitate Endotracheal Intubation?

Pseudocholinesterase (butyrylcholinesterase) deficiency is an inherited or acquired condition in which the serum pseudocholinesterase levels are absent or lower than normal. The enzyme is produced by the liver; decreased levels of the enzyme in an individual cause increased sensitivity to anesthetic agents, like succinylcholine and mivacurium. Pseudocholinesterase deficiency is caused by butyrylcholinesterase (BCHE) gene mutation, a gene that provides instructions for making the pseudocholinesterase enzyme. Succinylcholine is a depolarizing muscle relaxant that provides a quicker onset and a brief duration of muscle relaxation during general anesthesia. In this article, we would like to discuss a case report of prolonged intubation and ventilation in a patient with pseudocholinesterase deficiency and the necessity of succinylcholine during intubation in comparison to possible alternatives (rocuronium). 

Pseudocholinesterase Deficiency Considerations: A Case Study

Pseudocholinesterase deficiency, sometimes called butyrylcholinesterase deficiency, is a rare disorder in which the neuromuscular blocking drugs succinylcholine and mivacurium cannot be metabolized properly in the blood plasma. This disorder can either be acquired as a result of certain comorbidities or it can be inherited genetically. Anesthesia providers must understand the pathophysiology of pseudocholinesterase deficiency and be prepared to safely and effectively manage patients who show signs and symptoms consistent with the disorder after the use of the indicated neuromuscular blocking drugs. This article summarizes the pharmacologic and physiologic data relevant to understanding the basic pathophysiology associated with pseudocholinesterase deficiency and illustrates a case study of a young woman suspected of having the disorder after a prolonged delay in emergence from general anesthesia.

Current practice of rapid sequence induction in adults: A national survey among anesthesiologists in Spain

BACKGROUND

Rapid sequence induction (RSI) in adults has undergone changes in recent years due to pharmacological and technological advances. The objective of this survey was to evaluate current practice among Spanish anesthesiologists.

METHODS

A 31-item questionnaire regarding RSI practice was sent to anesthesiologists working in Spanish public hospitals. Differences in responses according to the type of hospital or experience of the respondent were compared for all data using the chi-square and Fisher's exact test.

RESULTS

Approximately 15.89% of Spanish anesthesiologists participated in the survey (1002 questionnaires). The results show considerable heterogeneity in most aspects of RSI. Less than 20% of respondents administer sodium citrate. Sixty-four percent place a nasogastric tube in patients with intestinal obstruction. Gastric residue is assessed by ultrasound in 6% of cases. Only 25% of respondents measure ETO₂ to check the effectiveness of preoxygenation, and 22% use nasal oxygen insufflation with nasal prongs or THRIVE. Sixty two percent of respondents apply cricoid pressure, but only 50% release the pressure when encountering intubation difficulty. Up to 40% of respondents reported cases of aspiration despite applying cricoid pressure. Propofol was the most commonly used hypnotic (97.6%), but there was no clear preference in the choice of neuromuscular relaxant (suxamethonium versus rocuronium ratio of approximately 1:1). Only 44% of respondents calculated the dose of sugammadex that would be required for emergency reversal of rocuronium.

CONCLUSIONS

The survey showed significant variation in RSI practice, similar to that of other countries. Quality prospective studies are needed to standardize clinical practice.