Risk Factors for Fentanyl-Induced Cough Following General Anesthesia in Adults: A Retrospective Study from a Single Center in China.

BACKGROUND Fentanyl-induced cough (FIC) during general anesthesia induction and postoperative nausea and vomiting are common complications, yet the risk factors for FIC remain controversial. This retrospective study was conducted at a single center in China and aimed to investigate the risk factors for fentanyl-induced cough following general anesthesia in adults. MATERIAL AND METHODS A total of 601 adult patients undergoing elective surgery were enrolled, and the incidence of FIC during general anesthesia induction and postoperative adverse events were recorded. The risk factors for FIC during general anesthesia induction and postoperative nausea and vomiting were assessed using multivariate logistic regression analysis. RESULTS The incidence of FIC, nausea, and vomiting were 21.8%, 6.3%, and 4.5%, respectively. The results of multivariate logistic regression analysis indicated that pharyngitis history was associated with an increased risk of FIC during general anesthesia induction (odds ratio [OR]: 2.852; 95% confidence interval [CI]: 1.698-4.792; P<0.001), whereas use of lidocaine could protect against FIC risk (OR: 0.649; 95% CI: 0.557-0.757; P<0.001). However, the characteristics of patients were not associated with the risk of postoperative nausea and vomiting. CONCLUSIONS The findings from this study showed that a history of pharyngitis increased the risk of FIC, while the use of lidocaine was associated with a reduced risk of FIC. The risk of postoperative nausea and vomiting was not affected by fentanyl use or patient characteristics.

Identification of independent risk factors for intraoperative gastroesophageal reflux in adult patients undergoing general anesthesia.

BACKGROUND: Gastroesophageal reflux (GER) affects up to 20% of the adult population and is defined as troublesome and frequent symptoms of heartburn or regurgitation. GER produces significantly harmful impacts on quality of life and precipitates poor mental well-being. However, the potential risk factors for the incidence and extent of GER in adults undergoing general anesthesia remain unclear. AIM: To explore independent risk factors for the incidence and extent of GER during general anesthesia induction. METHODS: A retrospective study was conducted, and 601 adult patients received general anesthesia intubation or laryngeal mask surgery between July 2016 and January 2019 in Shanghai General Hospital of Nanjing Medical University. This study recruited a total of 601 adult patients undergoing general anesthesia, and the characteristics of patients and the incidence or extent of GER were recorded. The potential risk factors for the incidence of GER were explored using multivariate logistic regression, and the risk factors for the extent of GER were evaluated using multivariate linear regression. RESULTS: The current study included 601 adult patients, 82 patients with GER and 519 patients without GER. Overall, we noted significant differences between GER and non-GER for pharyngitis, history of GER, other digestive tract diseases, history of asthma, and the use of sufentanil (P < 0.05), while no significant differences between groups were observed for sex, age, type of surgery, operative time, body mass index, intraoperative blood loss, smoking status, alcohol intake, hypertension, diabetes mellitus, psychiatric history, history of respiratory infection, history of surgery, the use of lidocaine, palliative strategies, propofol, or rocuronium bromide, state anxiety inventory, trait anxiety inventory, and self-rating depression scale (P > 0.05). The results of multivariate logistic regression indicated that female sex [odds ratio (OR): 2.702; 95% confidence interval (CI): 1.144-6.378; P = 0.023], increased age (OR: 1.031; 95%CI: 1.008-1.056; P = 0.009), pharyngitis (OR: 31.388; 95%CI: 15.709-62.715; P < 0.001), and history of GER (OR: 11.925; 95%CI: 4.184-33.989; P < 0.001) were associated with an increased risk of GER, whereas the use of propofol could protect against the risk of GER (OR: 0.942; 95%CI: 0.892-0.994; P = 0.031). Finally, age (P = 0.004), operative time (P < 0.001), pharyngitis (P < 0.001), history of GER (P = 0.024), and hypertension (P = 0.017) were significantly associated with GER time. CONCLUSION: This study identified the risk factors for GER in patients undergoing general anesthesia including female sex, increased age, pharyngitis, and history of GER.

Effect of Inhibiting p38 on HuR Involving in ß-AChR Post-transcriptional Mechanisms in Denervated Skeletal Muscle.

Previous studies reported that RNA-binding protein human antigen R (HuR) mediates changes in the stability of AChR ß-subunit mRNA after skeletal muscle denervation; also, p38 pathway regulated the stability of AChR ß-subunit mRNA in C2C12 myotubes. However, the relationship between HuR and p38 in regulating the stability of AChR ß-subunit mRNA have not been clarified. In this study, we wanted to examine the effect of inhibiting p38 on HuR in denervated skeletal muscle. Denervation model was built and 10% DMSO or SB203580 were administered respectively follow denervation. Tibialis muscles were collected in 10% DMSO-administered contralateral (undenervated) leg, 10% DMSO-administered denervated leg, SB203580-administered contralateral (undenervated) leg, and SB203580-administered denervated leg, respectively. P38 protein, ß-AChR mRNA and protein, HuR protein, ß-AChR mRNA stability, and HuR binding with AChR ß-subunit mRNAs were measured. Results demonstrated that the administration of SB203580 can inhibit the increase of ß-AChR protein expression and mRNA expression and stability, and RNA-binding protein human antigen R (HuR) expression, in cytoplasmic and nuclear fractions in skeletal muscle cells following denervation. Importantly, we observed that SB203580 also inhibited the increased level of binding activity between HuR and AChR ß-subunit mRNAs following denervation. Collectively, these results suggested that inhibition of p38 can post-transcriptionally inhibit ß-AChR upregulation via HuR in denervated skeletal muscle.

γ-Acetylcholine Receptor Mediating Dynamic Changes of Resistance to Rocuronium in the Denervated Skeletal Muscle.

BACKGROUND/AIMS: Denervation resulted in resistance to non-depolarizing muscle relaxants (NDMRs), the magnitude of which changed after denervation in the skeletal muscle. The aim of this study was to investigate whether changed potencies of rocuronium were due to altered γ-acetylcholine receptor (γ-AChR) expression after skeletal muscle denervation. METHODS: Innervated and denervated muscle cells were used in this study. Patch clamp and Western blotting techniques were separately applied to examine IC50 values of rocuronium and γ-AChR protein expression at different times after denervation. Then, using the linear Pearson correlation analysis, the relationship between IC50 values of rocuronium and γ-AChR expression was tested. RESULTS: Compared with the innervated control, both IC50 values of rocuronium and γ-AChR expression significantly increased at Day 4, 7, and 14 after denervation in the skeletal muscle. Furthermore, γ-AChR protein and IC50 values of rocuronium exibited a significant positive correlation (r = 0.7678, p < 0.0001). CONCLUSION: These above results indicated that dynamic changes of resistance to NDMRs may be due to altered γ-AChR expression after skeletal muscle denervation.

Effect of creatine phosphate sodium on bispectral index and recovery quality during the general anaesthesia emergence period in elderly patients: A randomized, double-blind, placebo-controlled trial.

Objective To evaluate the effect of creatine phosphate sodium on bispectral index (BIS) and recovery quality during the general anaesthesia emergence period in elderly patients. Methods This randomized, double-blind, placebo-controlled study enrolled patients undergoing transabdominal cholecystectomy under general anaesthesia. Patients were randomly assigned to receive either creatine phosphate sodium (1.0 g/100 ml 0.9% saline; group P) or 100 ml 0.9% saline (group C) over 30 minutes during surgical incision. The BIS values were recorded at anaesthesia induction (T0), skin incision (T1), cutting the gallbladder (T2), suturing the peritoneum (T3), skin closure (T4), sputum suction (T5), extubation (T6) and 1 min (T7), 5 min (T8), 10 min (T9), and 15 min (T10) after extubation. The anaesthesia duration, operation time, waking time, extubation time, consciousness recovery time, time in the postanaesthesia care unit (PACU), and the Steward recovery scores at T7, T8, T9 and T10 were recorded. Results A total of 120 elderly patients were randomized equally to the two groups. Compared with group C, the BIS values were significantly higher in group P at T5, T6, T7 and T8; and the Steward recovery scores at T7 and T8 were significantly higher in group P. The waking time, extubation time, consciousness recovery time and time in the PACU were significantly shorter in group P compared with group C. Conclusion Creatine phosphate sodium administered during transabdominal cholecystectomy can improve BIS values and recovery following general anaesthesia in elderly patients.

Airflow behavior changes in upper airway caused by different head and neck positions: Comparison by computational fluid dynamics.

The feasibility of computational fluid dynamics (CFD) to evaluate airflow characteristics in different head and neck positions has not been established. This study compared the changes in volume and airflow behavior of the upper airway by CFD simulation to predict the influence of anatomical and physiological airway changes due to different head-neck positions on mechanical ventilation. One awake volunteer with no risk of difficult airway underwent computed tomography in neutral position, extension position (both head and neck extended), and sniffing position (head extended and neck flexed). Three-dimensional airway models of the upper airway were reconstructed. The total volume (V) and narrowest area (Amin) of the airway models were measured. CFD simulation with an Spalart-Allmaras model was performed to characterize airflow behavior in neutral, extension, and sniffing positions of closed-mouth and open-mouth ventilation. The comparison result for V was neutral

Different sensitivities to rocuronium of the neuromuscular junctions innervated by normal/damaged facial nerves and somatic nerve in rats: the role of the presynaptic acetylcholine quantal release.

BACKGROUND: Muscles present different responses to muscle relaxants, a mechanism of importance in surgeries requiring facial nerve evoked electromyography under general anaesthesia. The non-depolarizing muscle relaxants have multiple reaction formats in the neuromuscular junction, in which pre-synaptic quantal release of acetylcholine was one of the important mechanisms. This study was to compare the pre-synaptic quantal release of acetylcholine from the neuromuscular junctions innervated by normal/damaged facial nerves and somatic nerve under the effect of rocuronium in rats in vitro. METHODS: Acute right-sided facial nerve injury was induced by nerve crush axotomies. Both sided facial nerve connected orbicularis oris strips and tibial nerve connected gastrocnemius strips were isolated to measure endplate potentials (EPP) and miniature endplate potentials (MEPP) using an intracellular microelectrode gauge under different rocuronium concentrations. Then, the pre-synaptic quantal releases of acetylcholine were calculated by the ratios of the EPPs and the MEPPs, and compared among the damaged or normal facial nerve innervated orbicularis oris and tibial nerve innervated gastrocnemius. RESULTS: The EPP/MEPP ratios of the three neuromuscular junctions decreased in a dose dependent manner with the increase of the rocuronium concentration. With the concentrations of rocuronium being 5 µg/ml, 7.5 µg/ml and 10 µg/ml, the decrease of the EPP/MEPP ratio in the damaged facial nerve group was greater than that in the normal facial nerve group. The decrease in the somatic nerve group was the biggest, with significant differences. CONCLUSIONS: Rocuronium presented different levels of inhibition on the pre-synaptic quantal release of acetylcholine in the three groups of neuromuscular junctions. The levels of the inhibition showed the following sequence: somatic nerve > damaged facial nerve > normal facial nerve. The difference may be one of the reasons causing the different sensitivities to rocuronium among the muscles innervated by the normal/injured facial nerves and the somatic nerve. The results may provide some information for the proper usage of muscle relaxants in surgeries requiring electromyographic monitoring for the pre-surgically impaired facial nerves.

Differences in sensitivity to rocuronium among orbicularis oris muscles innervated by normal or damaged facial nerves and gastrocnemius muscle innervated by somatic nerve in rats: combined morphological and functional analyses.

OBJECTIVES/HYPOTHESIS: To evaluate mechanisms of discrepant responses to the nondepolarizing muscle relaxant rocuronium among normal and injured facial nerve-innervated orbicularis oris and tibial nerve-innervated gastrocnemius, and to provide information for the proper use of muscle relaxants to balance evoked electromyography (EEMG) monitoring and immobility in general anesthesia. STUDY DESIGN: Randomized controlled study. METHODS: Right-sided facial nerve injury was induced by crush axotomy in 18 Sprague-Dawley rats. At different rocuronium concentrations, muscular tension amplitude (MTA) was determined in vitro for normal and injured facial nerve-innervated orbicularis oris and gastrocnemius; the number of unsaturated acetylcholine receptors (AChRs) at end plates was determined by (125) I-α-bungarotoxin staining followed with gamma spectroscopy. The morphological composition of muscle fibers was determined by histological examination. RESULTS: Following rocuronium incubation, the percentage of MTA inhibition (MTAI%) of gastrocnemius was significantly higher than the corresponding values of orbicularis oris (P < .05), and the degree of saturation of AChR in gastrocnemius was significantly greater than that in orbicularis oris (P < .05). The baseline MTA and AChR density of injured-side orbicularis oris was significantly smaller than those of the normal side, whereas no significant difference was found regarding MTAI% and the degree of AChR saturation between the normal and injured side. CONCLUSIONS: The affinity of AChR at end plates and different number of AChR per unit fiber cross-sectional area may be the mechanisms for differential sensitivities to neuromuscular blockers between facial nerve-innervated muscles and somatic nerve-innervated muscles. The lower EEMG responses in the impaired facial nerve-innervated muscles may result from the lower AChR density at end plates compared with the normal facial nerve-innervated muscles.

The comparison of various ventilation modes and the association of risk factors with CO2 retention during suspension laryngoscopy.

OBJECTIVES/HYPOTHESIS: To compare the effectiveness of various ventilation modes during suspension laryngoscopy and to investigate risk factors associated with CO(2) retention in high-frequency jet ventilation (HFJV). STUDY DESIGN: Part I: Randomized controlled study; Part II: Outcomes research. METHODS: In Part I, saturation of peripheral oxygen, partial pressure of carbon dioxide (PaCO(2) )(,) and pH were recorded in different ventilation modes in 60 patients. All subjects were randomly divided into four groups. Three groups received different jet ventilations through a catheter inserted transnasally, and one group had tracheal intubation and received intermittent positive pressure ventilation. In Part II, 59 patients received jet ventilation with a fixed rate; CO(2) retention and its potential risk factors were analyzed. Data were collected at the following time points: preinduction (T(0) ), anesthesia induction (T(1) ), laryngoscopic operation (T(2) ), 10 minutes after the initiation of ventilation (T(3) ), extubation (T(4) ), and 10 minutes after extubation (T(5) ). RESULTS: In Part I, mean arterial pressure (MAP) increased and heart rate decreased significantly during T(2) (P < .01), MAP and heart rate increased significantly during T(4) (P < .01), and PaCO(2) increased and pH decreased significantly in T(3) and T(5) (P < .01) in all four groups. Using logistic regression analysis of results from Part II, it was determined that in males, the combination of higher weight, lower height, and body mass index values greater than 25.224 was closely associated with CO(2) retention. CONCLUSIONS: During suspension laryngoscopy surgery, HFJV at 60 beats per minute through a thin transnasal catheter provides adequate ventilation as well as an excellent surgical view. A body mass index of more than 25.224 is the main risk factor for CO(2) retention.

Airway management in pediatric patients undergoing suspension laryngoscopic surgery for severe laryngeal obstruction caused by papillomatosis.

OBJECTIVES: To review perioperative airway management and ventilation strategy during the surgical removal of papilloma under suspension laryngoscopy in pediatric patients with severe airway obstruction. METHODS: Seventy pediatric patients with degree III and IV laryngeal obstruction who underwent suspension laryngoscopy to remove laryngeal papillomatosis, between July 2005 and March 2009, were included in the study. All patients were intubated initially to secure the airway. Controlled ventilation through an endotracheal (ET) tube was used during the papilloma debulking near the glottis vera. Spontaneous ventilation or apneic technique was adopted based on the stage of the surgical procedure and the location of the remaining tumor. Hemodynamic parameters, pulse oxygen saturation (SpO(2)), and CO(2) were closely monitored, and adverse events were recorded. RESULTS: The duration of the surgical operation and the duration of the extubation period were 5-35 min and 5-20 min, respectively. Thirty cases with degree III and twenty cases with degree IV laryngeal obstruction received inhalation induction. Sixteen cases with degree III laryngeal obstruction were given an intravenous induction. Four patients admitted with a comatose status were emergently intubated without any anesthetics. The ET tube size was determined by assessing the opening through the tumor mass or glottic aperture under direct laryngoscopy. SpO(2) was maintained above 97% after the airway was secured and sufficient ventilation established. Controlled ventilation was used in all children during the bulk removal of tumor. Spontaneous respiration and apneic technique were adopted for the removal of the remaining tumor in the hypolarynx or trachea in 16 and 28 cases, respectively. Three patients had to be re-intubated postoperatively because of persistent desaturation or laryngospasm. CONCLUSION: Key points of perioperative airway management in pediatric patients with papillomatosis-induced severe laryngeal obstruction include careful preoperative airway evaluation; the proper choice of induction methods, and ET tube size; maintenance of an adequate depth of anesthesia; and flexible ventilation strategy, continuous and close monitoring during the extubation and postextubation period; and prompt management of adverse events.

The risk factors for hypoxemia in children younger than 5 years old undergoing rigid bronchoscopy for foreign body removal.

BACKGROUND: Removal of an airway foreign body (FB) is usually performed by rigid bronchoscopy under general anesthesia, but the choice of anesthesia and ventilation techniques varies greatly among anesthesiologists and institutions. Hypoxemia is the most commonly observed adverse event during rigid bronchoscopy. It is influenced by a variety of factors including the patient's medical condition, the type of surgical procedure, and the anesthetic technique. In the current study, we investigated risk factors that statistically correlate with intraoperative or postoperative hypoxemia in young patients undergoing rigid bronchoscopy. METHODS: From January 2007 to December 2008, 384 children younger than 5-yr-of-age subjected to rigid bronchoscopy for FB removal were included in the study. The detailed clinical information and perioperative adverse events were recorded. Surgical outcomes and incidence of perioperative adverse events were compared among different ventilation modes (spontaneous ventilation, manual intermittent positive pressure ventilation, and manual jet ventilation) and different anesthetic techniques (total IV anesthesia and inhaled anesthesia). An amalgamated dataset was used for the analysis of factors that correlated with perioperative hypoxemia. RESULTS: In children who received total IV anesthesia with spontaneous ventilation during rigid bronchoscopy, we observed more intraoperative body movement and breath holding, significantly longer duration of emergence from anesthesia, lower percentage of successful FB removal, and more postoperative laryngospasm. Children in the manual jet ventilation group had the least occurrence of intraoperative hypoxemia. Five factors strongly correlated with intraoperative hypoxemia. Younger age, plant seed as the type of FB, longer surgical duration, pneumonia before the procedure, and spontaneous ventilation mode significantly increased the risk of intraoperative hypoxemia, whereas manual jet ventilation mode decreased it. Two factors were associated with postoperative hypoxemia: plant seed as a FB and prolonged duration of emergence from anesthesia. CONCLUSION: We identified risk factors associated with intraoperative or with postoperative hypoxemia in rigid bronchoscopy which included patient age, type of FB, duration of surgical procedure, pneumonia before the procedure, ventilation mode, and duration of emergence from anesthesia. These results provide evidence that will help clinicians to reduce the incidence of hypoxemia in high-risk children.

Electromyographic monitoring of facial nerve under different levels of neuromuscular blockade during middle ear microsurgery.

BACKGROUND: The evoked electromyography (EMG) is frequently used to identify facial nerve in order to prevent its damage during surgeries. Partial neuromuscular blockade (NMB) has been suggested to favor EMG activity and insure patients' safety. The aim of this study was to determine an adequate level of NMB correspondent to sensible facial nerve identification by evaluating the relationship between facial EMG responses and peripheral NMB levels during the middle ear surgeries. METHODS: Facial nerve evoked EMG and NMB monitoring were performed simultaneously in 40 patients who underwent tympanoplasty. Facial electromyographic responses were recorded by insertion of needle electrodes into the orbicularis oris and orbicularis oculi muscles after electrical stimulation on facial nerve. The NMB was observed objectively with the hypothenar muscle's twitching after electrical stimulation of ulnar nerve, and the intensity of blockade was adjusted at levels of 0, 25%, 50%, 75%, 90%, and 100% respectively with increased intravenous infusion of Rocuronium (muscle relaxant). RESULTS: All of the patients had detectable EMG responses at the levels of NMB or= 75%. A significant linear positive correlation was present between stimulation thresholds and NMB levels while a linear negative correlation was present between EMG amplitudes and NMB levels. CONCLUSIONS: The facial nerve monitoring via facial electromyographic responses can be obtained when an intraoperative partial neuromuscular blockade is induced to provide an adequate immobilization of the patient. The 50% NMB should be considered as the choice of anesthetic management for facial nerve monitoring in otologic microsurgery based on the relationship of correlation.

Adsorption of carboxylate-modified gold nanoparticles on an octadecylamine monolayer at the air/liquid interface.

Gold nanoparticles (Au NPs) were prepared and surface-modified by mercaptosuccinic acid (MSA) to render a surface with carboxylic acid groups (MSA-Au). Octadecylamine (ODA) was used as a template monolayer to adsorb the Au NPs dispersed in the subphase. The effect of MSA concentration on the incorporation of Au NPs on the ODA monolayer and the relevant behavior of the mixed monolayer were studied using the pressure-area (pi-A) isotherm and transmission electron microscopy (TEM) observations. The experimental results showed that the adsorbed density of Au NPs is low without the surface modification by MSA. When MSA was added into the Au NP-containing subphase, the incorporation amount of Au NPs increased with increasing MSA concentration up to approximately 1 x 10-5 M for the particle density of 1.3 x 1011 particles/mL. With a further increase in the MSA concentration, the adsorbed particle density decreases due to competitive adsorption between the free MSA molecules and the MSA-Au NPs. It is inferred that free MSA molecules adsorb more easily than the MSA-Au NPs on the ODA monolayer. Therefore, an excess amount of MSA present in the subphase is detrimental to the incorporation of gold particles. The study on the monolayer behavior also shows that the pi-A isotherm of the ODA monolayer shifts right when small amounts of Au NPs or free MSA molecules are incorporated. However, when larger amounts of particles are adsorbed at the air/liquid interface, a left shift of the pi-A isotherm appears, probably due to the adsorption of ODA molecules onto the particle surface and the transferring of the particles from beneath the ODA monolayer to the air/water interface. According to the present method, it is possible to prepare uniform particulate films of controlled densities by controlling the particle concentration in the subphase, the MSA concentration, and the surface pressure of a mixed monolayer.