The optimum bolus dose of remifentanil to facilitate laryngeal mask airway insertion with a single standard dose of propofol at induction in children

Spectral EEG correlations from the different phases of general anesthesia

Introduction

Electroencephalography (EEG) signals contain transient oscillation patterns commonly used to classify brain states in responses to action, sleep, coma or anesthesia.

Methods

Using a time-frequency analysis of the EEG, we search for possible causal correlations between the successive phases of general anesthesia. We hypothesize that it could be possible to anticipate recovery patterns from the induction or maintenance phases. For that goal, we track the maximum power of the α-band and follow its time course.

Results and discussion

We quantify the frequency shift of the α-band during the recovery phase and the associated duration. Using Pearson coefficient and Bayes factor, we report non-significant linear correlation between the α-band frequency and duration shifts during recovery and the presence of the δ or the α rhythms during the maintenance phase. We also found no correlations between the α-band emergence trajectory and the total duration of the flat EEG epochs (iso-electric suppressions) induced by a propofol bolus injected during induction. Finally, we quantify the instability of the α-band using the mathematical total variation that measures possible deviations from a flat line. To conclude, the present correlative analysis shows that EEG dynamics extracted from the initial and maintenance phases of general anesthesia cannot anticipate both the emergence trajectory and the extubation time.

General Anesthesia Maintained with Sevoflurane versus Propofol in Pediatric Surgery Shorter Than 1 Hour: A Randomized Single-Blind Study

Background

Sevoflurane was compared with propofol for general anesthesia maintenance in pediatric operations lasting less than 1 hour in terms of anesthetic effect and postoperative recovery.

Material/Methods

Children scheduled for inguinal hernia repair or hydrocele testis repair were randomly assigned to receive general anesthesia maintained with either sevoflurane (n=43) or propofol (n=43). The ilioinguinal nerve was blocked with 1% lidocaine (7 mg/kg) after intravenous administration of ketamine (2 mg/kg). At the end of the surgery in patients receiving sevoflurane, sevoflurane was stopped and a bolus of propofol of 1 mg/kg was administered.

Results

Sevoflurane was associated with significantly less use of ketamine (35.1±10.6 mg) than was propofol (59.0±28.0 mg; P<0.001). In addition, sevoflurane was associated with a significantly shorter time in the post-anesthesia care unit (52.1±9.0 min) than was propofol (68.8±15.3 min; P<0.001). Propofol was associated with a significantly higher incidence of intraoperative body movement (33.3%) than was sevoflurane (13.5%; P=0.045). However, the 2 groups showed no important differences in other adverse events such as hypoxia, emergence agitation, and additional use of propofol.

Conclusions

In pediatric surgery lasting less than 1 hour, anesthesia maintained with sevoflurane was associated with significantly less use of ketamine, shorter postoperative recovery time, and less intraoperative body movement than was propofol.

Patients' satisfaction with anesthesia in enzymatic debridement from a surgical perspective

INTRODUCTION

Various clinical studies found that enzymatic debridement (EDNX) is superior to tangential excision after severe burns. The current study evaluates patients' satisfaction with pain management in EDNX with special respect to different anesthesia techniques.

METHODS

Between 2015 and 2016, all patients at a department of plastic surgery were asked to complete a German-wide validated pain questionnaire. In a retrospective study design, satisfaction with pain management was compared between the control group (diagnosis from the whole field of plastic surgery except burns) and the EDNX group (burns treated with EDNX only). Analgosedation, general, regional and local anesthesia were chosen for pain management.

RESULTS

In the control group 403 patients (153 females, 250 males, medium age 53 years) could be included The EDNX group included 88 patients (20 females, 68 males, medium age 38 years). The mean burn size was 5.3% TBSA. Between 0.5%-10.5% of the surface was treated with EDNX. EDNX patients could be treated under analgosedation and regional anesthesia, by topical anesthesia creme and without any anesthesia. They reported less pain during stress (p = 0.04) and were less frequently affected by motion (p = 0.024) and nausea (<0.001). However, they felt that they need more information about alternative anesthetic treatments (<0.001).

CONCLUSION

EDNX can be performed sufficiently either under analgosedation, regional or local anesthesia. Thus, side effects of general anesthesia can be reduced and treatment costs can be decreased. However, it was found that neither after topical anesthetic creme nor after hand block pain treatment was sufficient.

Postoperative pain management in children: Guidance from the pain committee of the European Society for Paediatric Anaesthesiology (ESPA Pain Management Ladder Initiative)

The main remit of the European Society for Paediatric Anaesthesiology (ESPA) Pain Committee is to improve the quality of pain management in children. The ESPA Pain Management Ladder is a clinical practice advisory based upon expert consensus to help to ensure a basic standard of perioperative pain management for all children. Further steps are suggested to improve pain management once a basic standard has been achieved. The guidance is grouped by the type of surgical procedure and layered to suggest basic, intermediate, and advanced pain management methods. The committee members are aware that there are marked differences in financial and personal resources in different institutions and countries and also considerable variations in the availability of analgesic drugs across Europe. We recommend that the guidance should be used as a framework to guide best practice.

The optimum sevoflurane concentration for supraglottic airway device Blockbuster™ insertion with spontaneous breathing in obese patients: a prospective observational study

BACKGROUND

Airway management of the obese patient presenting for surgery is more likely to be a challenging problem. Supraglottic airway device has been adopted as a bridge to connect ventilation and tracheal intubation in obese patients who would be suffered with difficult intubation. The optimum sevoflurane concentration for supraglottic airway device insertion allowing spontaneous breathing in 50% of obese patients (ED₅₀) is not known. The purpose of this study was to determine the ED₅₀ of sevoflurane for supraglottic airway device Blockbuster™ insertion with spontaneous breathing in obese patients requiring general anesthesia.

METHODS

Thirty elective obese patients (body mass index 30-50 kg/m²) undergoing bariatric surgery were recruited in this study. The predetermined target sevoflurane concentration (initiating at 2.5% with 0.5% as a step size) was sustained for >5 min using a modified Dixon's up-and-down method, and then the supraglottic airway device Blockbuster™ was inserted. The patient's response to supraglottic airway device insertion was classified as either 'movement' or 'no-movement'. The ED₅₀ of sevoflurane were determined by calculating the midpoint concentration of crossover point from 'movement' or 'no-movement' response.

RESULTS

The ED₅₀ of sevoflurane for supraglottic airway device Blockbuster™ insertion in obese patients calculated using up-and-down method were 2.50 ± 0.60%. The ED₅₀ and ED₉₅ (95% confidence interval) obtained by probit regression analysis were 2.35 (1.28-3.42) % and 4.03 (3.16-17.83) % for supraglottic airway device Blockbuster™ insertion, respectively.

CONCLUSION

We conclude that the optimum end-tidal sevoflurane concentration required for the supraglottic airway device Blockbuster™ insertion allowing spontaneous breathing in 50% of obese patients (ED₅₀) is 2.5 ± 0.6%.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-IPR-16009071 , Registered on 24 August 2016.

Effect of Paralysis at the Time of ProSeal Laryngeal Mask Airway Insertion on Pharyngolaryngeal Morbidities. A Randomized Trial

Neuromuscular block results in the loss of muscular tone in the upper airway, which might contribute to the increased postoperative airway morbidity followed by ProSeal laryngeal mask airway (PLMA) insertion. We compared the pharyngolaryngeal discomfort exerted by the PLMA according to the neuromuscular block. One hundred sixty patients undergoing surgery for breast disease or inguinal hernia were anesthetized with propofol and remifentanil by target controlled infusion. Rocuronium 0.6 mg/kg (NMBA group, n = 80) or normal saline (No-NMBA group, n = 80) was administered after the loss of consciousness, and one anesthesiologist inserted the PLMA. Postoperative pharyngolaryngeal discomfort was evaluated at postoperative 1 h. Traumatic event was recorded based on the blood trace on the surface of the PLMA cuff. Insertion time, insertion attempt number, sealing pressure, and fiberoptic brochoscopic grades were evaluated. Patients’ characteristics and the PLMA insertion condition (insertion time, successful insertion attempt number, fiberoptic bronchoscopic grade, and sealing pressure) were similar between the two groups. The PLMA can be successfully inserted in non-paralyzed patients with less postoperative pharyngolaryngeal discomfort than when a neuromuscular blocking agent is used (13.8% vs. 30.0%, P = 0.021). The incidence of traumatic events is also reduced when no neuromuscular blocking agent is used (16.3% vs. 32.5%, P = 0.026). Regardless of whether or not a surgical procedure requires muscular relaxation, there is no need to administer neuromuscular blocking agents solely for the purpose of PLMA insertion.

The effective bolus dose of remifentanil to facilitate laryngeal mask airway insertion during inhalation induction of sevoflurane in children

PURPOSE

The additional administration of remifentanil during inhalation induction with sevoflurane could provide better conditions for laryngeal mask airway (LMA) insertion than sevoflurane alone. This study was designed to evaluate the 50 % effective bolus dose (ED50) and 95 % effective bolus dose (ED95) of remifentanil required for LMA insertion in children during inhalation induction with sevoflurane.

METHODS

Pediatric patients aged 3-12 years requiring general anesthesia were recruited. A predetermined dose of remifentanil was injected over 30 s after the induction of general anesthesia with sevoflurane. LMA insertion was attempted 60 s after remifentanil injection. The dose of remifentanil was determined using the Dixon's up-and-down method, starting from 0.5 μg/kg (step size of 0.05 μg/kg).

RESULTS

The study was conducted until seven cross-over points and 29 children were collected. The ED50 of remifentanil for successful LMA insertion during sevoflurane inhalation induction in children was 0.168 ± 0.035 μg/kg using Dixon's method. In addition, the ED50 and ED95 of remifentanil from the probit analysis were 0.176 μg/kg (95 % confidence limits, 0.102-0.216 μg/kg) and 0.268 μg/kg (95 % confidence limits, 0.223-0.659 μg/kg), respectively.

CONCLUSION

The ED50 and ED95 of remifentanil for successful LMA insertion in children were estimated to be 0.176 (0.168) and 0.268 μg/kg during inhalation induction with 2.1 % sevoflurane.

Estimation of the minimum effective dose of tramadol for postoperative analgesia in infants using the continual reassessment method

Tramadol is a potent analgesic. However, the analgesia efficacy of tramadol, particularly its minimum effective dose (MED), is not clear. The aim of this study is to find MED of tramadol for postoperative analgesia in infants. The continual reassessment method (CRM) was performed to find MED. Infants undergoing surgeries were included in the 3 phases of this series. In each phase, 24 participants were allocated a different tramadol dose. Pain intensity was measured by face, legs, activity, cry, consolability (FLACC) measurement at 3-hour intervals. Tramadol was considered ineffective if the FLACC score was higher than 4 in 10 at anytime. In phase 1, seven dose levels were used within the range 0.1-0.4 mg·kg(-1)·h(-1). Phase 1 was insufficient to identify the MED, and we increased the dose to 0.4-0.8 mg·kg(-1)·h(-1) in phase 2. Phase 2 was insufficient to identify the MED. In phase 3, local anesthetic wound infiltration was introduced, and the tramadol dose levels tested were the same as in phase 1. The successful analgesia probability of tramadol 0.4 mg·kg(-1)·h(-1) was 82.1% (95% CI, 0.742-0.925) in phase 1. In phase 2, it was 84.7% (95% CI, 0.789-0.991) with the dose 0.8 mg·kg(-1)·h(-1). Phase 1 and phase 2 were insufficient to identify the MED. In phase 3, the successful analgesia probability for dose 0.35 mg·kg(-1)·h(-1) was 96.7% (95% CI, 0.853-0.997).We have demonstrated that tramadol provides insufficient analgesia for surgeries considered to cause moderate-to-severe postoperative pain in infants if used as the sole analgesic, and that local anesthetic wound infiltration enhances the efficacy of tramadol.

Remifentanil in children

Remifentanil has gained the confidence of anesthesiologists and has given a real opportunity to change the way anesthesia is given. It can be considered the ideal opioid despite many obstacles to pediatric use: the condition of 'off-label', the lack of wide randomized clinical trials, and the fear of adverse events because of its high potency. Experiences in the field with this opioid over the years encouraged its use. Use has been associated with N(2)0 and volatile agents for general anesthesia and with propofol for total intravenous anesthesia (TIVA). It seems very useful for sedation inside and outside the operating room and in intensive care for both short painful procedures and synchronization with mechanical ventilation. However, its unique pharmacokinetic characteristics causing rapid onset and offset of effect appear unchanged in small children and even in premature neonates and need to be really confirmed by further pharmacokinetic studies. Moreover, the real risks of tolerance and hyperalgesia should be evaluated in the pediatric population. In this review, we go through the newer aspects of this versatile drug that has been proposed as 'the pediatric anesthetist's opiate'.

Recent Publications on Medications and Pharmacy

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