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Background Intravenous use of sufentanil can elicit cough. This study aimed to evaluate the inhibitory effect of pre-injection of a mall dose of remifentanil on sufentanil-induced cough during the induction of general anesthesia. Methods This prospective, randomized, controlled trial was conducted from January 10, 2019 to March 01, 2019. A total of 100 patients undergoing elective surgery under general anesthesia were enrolled, and at last 84 patients were included and randomly allocated into two equal size groups ( n = 42): Patients in the Remifentanil group (R group) received an intravenous infusion of remifentanil 0.3 μg/kg (diluted to 2 ml) 1 min before sufentanil injection; patients in the Control group (C group) received 2 ml of normal saline (NS) at the same time point. Injections of patients in both groups were completed within 5 s. Then, sufentanil 0.5 μg/kg was injected within 5 s and the number of coughs that occurred within 1 min after sufentanil injection were recorded. One minute after sufentanil injection, etomidate 0.3 mg/kg and cisatracurium 0.15 mg/kg were given for general anesthesia induction irrespective of the presence or absence of cough. The mean arterial pressure (MAP) and heart rate (HR) at time points just before remifentanil pretreatment administration (T0), 3 min after administration (T1), 1 min after intubation (T2), and 3 min after intubation (T3) were recorded. Results The incidence of cough in patients in the R group and C group was 4.8 and 31%, respectively. Compared with group C, the incidence and severity of cough in group R was significantly lower ( P < 0.01). No significant differences were observed in MAP and HR at the time of general anesthesia induction between the two groups ( P > 0.05). Conclusion Pretreatment with a small dose of remifentanil effectively and safely reduced the incidence and severity of cough induced by sufentanil during anesthesia induction and can be used as an alternative treatment to inhibit coughing caused by sufentanil. Trial registration Chinese Clinical Trial Registry (ChiCTR1900020587, registered date: January 9, 2019), http://www.chictr.org.cn Electronic supplementary material The online version of this article (10.1186/s12871-019-0836-1) contains supplementary material, which is available to authorized users.

Background Neuromuscular blockade is a risk factor for postoperative respiratory weakness during the immediate postoperative period. The quantitative relationships between postoperative pulmonary-function impairment and residual neuromuscular blockade are unknown. Methods 113 patients who underwent elective laparoscopic cholecystectomy were enrolled in this study. They all had a pulmonary-function test (PFT) during the preoperative evaluation. Predictive values based on demographic data were also recorded. The train-of-four ratio (TOFR) was recorded at the same time as the PFT and at every 5 minutes in the qualified 98 patients in the postanesthesia care unit (PACU). We analyzed the degree of PFT recovery when the TOFR had recovered to different degrees. Results There was a significant difference (P < 0.05) between the preoperative baseline value and the postoperative forced vital capacity at each TOFR point, except at a TOFR value of 1.1. There was also a significant difference (P < 0.05) between the preoperative baseline value and the postoperative peak expiratory flow at each TOFR point. Conclusions Postoperative residual neuromuscular blockade was common (75.51%) after tracheal extubation, and pulmonary function could not recover to an acceptable level (85% of baseline value), even if TOFR had recovered to 0.90. Trial Registration Chinese Clinical Trial Register is ChiCTR-OOC-15005838.

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Aims: Dexmedetomidine is highly specific α2-adrenoceptor agonist. A single bolus of dexmedetomidine can achieve clinical therapeutic effect. Therefore, it is essential to know the safety margin between the clinical effectiveness dosages of dexmedetomidine and its side effect. Methods:A total of 42 patients who underwent elective thyroidectomy were enrolled in this study. Dexmedetomidine was given as a single bolus injection 30 min towards the end of surgery. The up-and-down sequential schedule was used in this study. The starting dose of dexmedetomidine was set at 0.1 μg/kg in the first patient and the next patient would then receive a dose of dexmedetomidine decremented by 0.05 μg/kg if the prior patient's baseline heart rate (HR) had a decrease of ≥20% and/or mean arterial blood pressure (MAP) increase or decrease of ≥20%, otherwise, the following patient would receive an incremental 0.05 μg/kg dose of dexmedetomidine. The analytic techniques of linear, linear-logarithmic, exponential regressions and centred isotonic regression were used to determine the ED50 of dexmedetomidine and the residual standard errors were calculated for the comparison of goodness of fit among the different models. Results: The median (interquartile range [range]) lowest HR was 57 beats/min(53-63.3[46-76]) with an average HR decrease of 8.0 beats/min (5-13 [4 to 23]). The median (interquartile range [range]) highest MAP was 98 mmHg (91.8-105 [83-126]) with a MAP increase of 10.0 mmHg (6.8-18.0 [2-24]). The ED50 (95% confidence interval) from 4 different statistical approaches (linear, linear-logarithmic, exponential regressions and centred isotonic regression) were 0.262 μg/kg (0.243, 0.306), 0.252 μg/kg (0.238, 0.307), 0.283 μg/kg (0.238, 0.307), and 0.278 μg/kg, respectively. Among the 4 models, the exponential regression had the least residual standard error (0.03618). Conclusion:The ED50 derived from 4 statistical models for an intravenous bolus of dexmedetomidine without significant haemodynamic effects was distributed in a narrow range of 0.252-0.283 μg/kg, and the exponential regression was the model to best match the study data.

Background The objective of this study was to assess the inhibitory effect of intravenous injection of butorphanol on the shivering in those parturients who underwent cesarean section (CS) under epidural anesthesia (EA). Methods 160 parturients planned for elective CS under EA were enrolled and finally 155 of them were included in this trial and randomly allocated to 4 groups. Before epidural anesthesia, parturients in Group A, B and C were respectively injected 7.5μg/kg, 5μg/kg and 2.5μg/kg butorphanol (100ug/ml) while none in Group D was given any drug. The incidence, duration and intensity of shivering, hemodynamic parameters of parturients, Apgar score of neonates, analysis of blood gas of umbilical cord and adverse events were recorded. Results The demographic characteristics of parturients of the four groups were similar. Compared with the control group (Group D), statistically significant attenuation of shivering was seen in the parturients of Group A and Group B. The incidence, intensity and duration of shivering of the Group A and Group B were all lower than those of the control group, but there was no statistical difference in the incidence, severity or duration time of shivering among groups receiving butorphanol. No patient displayed grade 4 shivering. There were no significant differences among the groups with mean arterial pressure (MAP), heart rate (HR), pulse oxygen saturation (SpO2), respiratory rate (RR) after administration of butorphanol. The incidences of most adverse effects such as nausea and vomiting, respiratory depression, and hypotension were also not seen statistical difference among the four groups. However, compared with other three groups, sedation parameter increased in Group A. Compared with Groups C and Group D, incidences of dizziness increased in Group A and Group B. There was no significant difference in Apgar score, PH, PCO2, PO2, HCO3- and lactic acid value among the newborns of the four groups. Conclusion The prophylactic administration of intravenous butorphanol 0.75μg/kg or 0.5μg/kg is effective on inhibiting shivering and can be safely used in parturients undergoing CS under EA, but 0.5μg/kg is more suitable because of less sedation. Dizziness of parturients should be monitored whichever dose is used.

AIM: To describe the morphological characteristics of foveal avascular zone (FAZ) in normal Chinese adults with or without myopia by swept-source optical coherence tomography angiography (SS-OCTA) and analyze the possible associated factors. METHODS: Normal Chinese adults with or without myopia aged between 18 and 60y were recruited into the study. One eye in each individual was randomly selected for scanning using SS-OCTA. FAZ parameters, central retinal thickness (CRT) and central choroidal thickness (CCT) were then analyzed. Correlations between systemic and ocular variables and FAZ parameters were subsequently evaluated. The subgroup analysis based on refractive error was also carried out. RESULTS: In total, 127 eyes out of 127 normal subjects were finally included in the study (mean age 29.5±8.22y, 61 males and 66 females). The pattern of FAZ was variable: round configuration in 28 eyes (22%), quadrilateral configuration in 23 eyes (18%), pentagonal configuration in 20 eyes (16%), oval configuration in 15 eyes (12%), triangular configuration in 6 eyes (5%) and irregular configuration in 35 eyes (28%). The mean area of FAZ was 0.37±0.12 mm2. Females had a larger FAZ (0.41±0.11 mm2 vs 0.32±0.11 mm2) compared with that of males (P<0.01). All myopic individuals showed smaller FAZ area and perimeter compared with that of normal individuals (P<0.01). There was no obvious correlation between age and FAZ. In the univariate regression analysis, both axial length (AL) and refractive error were significantly related to FAZ parameters. However, only CRT showed negative correlation with FAZ in the multivariate regression analysis. CONCLUSION: The pattern of FAZ configuration in normal Chinese adults with or without myopia is highly variable. Establishing quantitative parameters of FAZ would not only provide details of macular pathophysiology but could possibly contribute as a biomarker in disease staging.