Anesthetic Agents and Cardiovascular Outcomes of Noncardiac Surgery after Coronary Stent Insertion

Patients undergoing noncardiac surgery after coronary stent implantation are at an increased risk of thrombotic complications. Volatile anesthetics are reported to have organ-protective effects against ischemic injury. Propofol has an anti-inflammatory action that can mitigate ischemia-reperfusion injury. However, the association between anesthetic agents and the risk of major adverse cardiovascular and cerebral event (MACCE) has never been studied before. In the present study, a total of 1630 cases were reviewed. Four different propensity score matchings were performed to minimize selection bias (propofol-based total intravenous anesthesia (TIVA) vs. volatile anesthetics; TIVA vs. sevoflurane; TIVA vs. desflurane; and sevoflurane vs. desflurane). The incidence of MACCE in these four propensity score-matched cohorts was compared. As a sensitivity analysis, a multivariable logistic regression analysis was performed to identify independent predictors for MACCE during the postoperative 30 days both in total and matched cohorts (TIVA vs. volatile agent). MACCE occurred in 6.0% of the patients. Before matching, there was a significant difference in the incidence of MACCE between TIVA and sevoflurane groups (TIVA 5.1% vs. sevoflurane 8.2%, p = 0.006). After matching, there was no significant difference in the incidence of MACCE between the groups of any pairs (TIVA 6.5% vs. sevoflurane 7.7%; p = 0.507). The multivariable logistic regression analysis revealed no significant association of the volatile agent with MACCE (odds ratio 1.48, 95% confidence interval 0.92–2.37, p = 0.104). In conclusion, the choice of anesthetic agent for noncardiac surgery did not significantly affect the development of MACCE in patients with previous coronary stent implantation. However, further randomized trials are needed to confirm our results.

The Hemodynamic Effect of Epinephrine-Containing Local Infiltration Analgesia After Tourniquet Deflation During Total Knee Arthroplasty: A Retrospective Observational Study

BACKGROUND

Local infiltration analgesia (LIA) is widely used in patients undergoing total knee arthroplasty and often contains epinephrine for a prolonged analgesic effect and to reduce systemic absorption of the local anesthetic. This retrospective observational study investigated the hemodynamic effect of locally infiltrated epinephrine after deflation of the tourniquet during total knee arthroplasty.

METHODS

We reviewed the electronic medical records of patients who underwent total knee arthroplasty between January 2017 and February 2018 at a tertiary care university hospital. Total knee arthroplasty was performed using a conventional technique with a pneumatic tourniquet. LIA consisted of ropivacaine, morphine sulfate, ketorolac, and methylprednisolone. The patients were grouped according to whether or not epinephrine was included in the LIA. The incidence of a hypertensive response (systolic blood pressure >160 mmHg or mean blood pressure >110 mmHg) after deflation of the tourniquet was compared between the 2 groups.

RESULTS

A total of 452 patients had received LIA with (n = 188) or without (n = 264) epinephrine. A hypertensive response after deflation of the tourniquet was more common in patients who received LIA containing epinephrine (42/188 [22.3%]) than in those who received LIA without epinephrine (14/264 [5.3%], P < .001). However, the incidence of hypotension after deflation of the tourniquet was not significantly different between the 2 groups (P = .976).

CONCLUSION

Because epinephrine-containing LIA can result in a hypertensive response after deflation of the tourniquet during total knee arthroplasty, it should be cautiously administered, especially in patients with cardiovascular comorbidities.

Comparison of the Effects of Sufentanil and Fentanyl in Intravenous Patient-Controlled Analgesia after Pediatric Moyamoya Surgery: A Retrospective Study

INTRODUCTION

Intravenous patient-controlled analgesia (PCA) has been one of the most popular modalities for postoperative pain management in orthopedic surgery, plastic surgery, or neurosurgery in children.

OBJECTIVE

We compared the effects of fentanyl and sufentanil used in intravenous PCA on postoperative pain management and opioid-related side effects in pediatric moyamoya disease.

METHODS

This retrospective study included 97 pediatric patients who underwent surgery for moyamoya disease. Preoperative and perioperative parameters were assessed. The PCA regimen was as follows: fentanyl group (0.2 μg/kg/mL, 1 mL of loading volume, 0.1 μg/kg/h of basal infusion, a bolus of 0.2 μg/kg on demand, "lock-out" interval of 15 min); sufen-tanil group (0.04 μg/kg/mL, 1 mL of loading volume, 0.02 μg/kg/h of basal infusion, a bolus of 0.04 μg/kg on demand, 15 min lock-out), 10 μg/kg (up to 300 μg) of ramosetron for prophylaxis of postoperative nausea and vomiting with the same loading dose in both groups. Peripheral nerve blocks were performed. Pain was assessed by numeric rating scale or revised Faces Pain Scale. Side effects were reviewed.

RESULTS

The two groups showed similar pain scores and incidence of nausea or vomiting during the first 48 h postoperatively. Additional analgesics were more frequent in the fentanyl group, and PCA was discontinued more frequently in the sufentanil group.

CONCLUSIONS

Postoperatively, sufen-tanil in PCA provided more analgesia than fentanyl with less additional analgesics in moyamoya disease. However, PCA with sufentanil was more frequently discontinued due to nausea or vomiting compared to fentanyl-based PCA.

Flow-Mediated Dilatation of the Brachial Artery for Assessing Endothelial Dysfunction in Children with Moyamoya Disease

BACKGROUND

Moyamoya disease is a progressive, steno-occlusive arteriopathy involving the internal carotid artery and its branches and causing recurrent stroke episodes in children. Patients with moyamoya disease may be more susceptible to influences that cause endothelial dysfunction. We evaluated whether flow-mediated dilatation (FMD) of the brachial artery is useful for assessing endothelial dysfunction in children with moyamoya disease.

METHODS

This prospective observational study included 30 children with moyamoya disease and 30 controls. After anesthesia induction, a blood pressure cuff was applied to the forearm and inflated to a pressure that was 50 mm Hg above the baseline systolic blood pressure for 5 min. From 30 s before to 2 min after deflation, the brachial artery diameter was recorded on ultrasound. The increase in internal diameter was expressed as the percentage of the baseline diameter.

RESULTS

Fifty-nine patients were analyzed. Baseline brachial artery diameters in the moyamoya and control groups were 3.00 and 3.37 mm, respectively (p = 0.004; difference, 0.38; 95% CI 0.12-0.63), while those after deflation were 3.06 and 3.48 mm, respectively (p = 0.003; difference, 0.42; 95% CI 0.15-0.68). The percent change of the baseline diameter value was 4.0% in the disease group and 8.3% in the control group (p = 0.10). There was a group and time interaction for brachial artery diameter (p = 0.01; main effect of group, p = 0.009; main effect of time, p = 0.007).

CONCLUSION

FMD of the brachial artery may not be enough for determining endothelial dysfunction under general anesthesia in children with moyamoya disease.

Is dynamic arterial elastance a predictor of an increase in blood pressure after fluid administration in pediatric patients with hypotension? Reanalysis of prospective observational studies

BACKGROUND

Dynamic arterial elastance (Ea_dyn ) has been proposed to predict an increase in mean arterial pressure (MAP) after volume expansion in hypotensive adults. We aimed to evaluate the clinical usefulness of Ea_dyn as a predictor of arterial pressure response after fluid loading in pediatric patients with hypotension.

METHODS

We re-analyzed data of 63 hypotensive children (age, ≤5 years), collected from three previous prospective observational studies about fluid responsiveness. Pulse pressure variation (PPV), stroke volume variation (SVV), and respiratory variation in aortic blood flow velocity (ΔVpeak) were used to calculate Ea_dyn (PPV/SVV) and modified Ea_dyn (PPV/ΔVpeak). Preload-dependent patients were defined as those with ΔVpeak ≥12% before fluid loading. Patients were classified as pressure responders, if their MAP increased ≥15% after fluid administration.

RESULTS

Mean Ea_dyn (SD) was 1.06 (0.47) in pressure responders (n=39) and 0.99 (0.48) in nonresponders (n = 24) (mean difference, 0.08; 95% confidence interval [CI], -0.19-0.34; P = .567). Additionally, mean modified Ea_dyn was 1.27 (0.64) in responders and 1.11 (0.43) in nonresponders (mean difference, 0.17; 95% CI, -0.13-0.46; P = 0.269). Both Ea_dyn (AUC 0.506; 95% confidence interval [CI], 0.337 to 0.675; P = 0.948) and modified Ea_dyn (AUC 0.498; 95% CI, 0.328-0.669; P = 0.983), as well as other dynamic variables, could not predict pressure responsiveness in children. Sub-group analysis revealed similar findings in both in 39 preload-dependent and hypotensive patients (26 pressure responders and 13 nonpressure responders).

CONCLUSION

Both Ea_dyn and modified Ea_dyn cannot predict whether blood pressure increases with fluid administration in pediatric patients with hypotension.

Selective Deposition of Al₂O₃ on the Upper Side-Photoelectrode to Improve Dye-Sensitized Solar Cell Efficiency

Charge recombination at the photoelectrode/dye/electrolyte interface decreases the energy conversion efficiency of dye-sensitized solar cells (DSSCs). To suppress charge recombination at this interface in DSSCs, an aluminum oxide (Al₂O₃) film can be deposited as an insulating metal oxide layer on the photoelectrode to form an energy barrier. However, the Al₂O₃ energy barrier can also disturb the transport of injected electrons to the working electrode through the titanium dioxide (TiO₂) photoelectrode. In this study, Al₂O₃ was selectively deposited as an insulating metal oxide layer on the upper side of a TiO₂ photoelectrode, which has a high probability of charge recombination, using plasma-enhanced atomic layer deposition. Deposition of the Al₂O₃ layer by this method helped to minimize the transport rate deterioration of injected electrons. This resulted in an increase of the efficiency of DSSCs containing the Al₂O₃ layer by 42.3% compared with that of a reference DSSC without the insulating metal oxide layer.

Influence of age, laterality, patient position, and spinal level on the interlamina space for spinal puncture

BACKGROUND AND OBJECTIVES

The lumbar interlamina space height is an important determinant of successful spinal puncture. We aimed to evaluate the influence of age, laterality, patient position, and spinal level on the height of the interlamina window using ultrasonography.

METHODS

Ultrasonographic examination was performed in 20 adult patients aged under 40 years (group Y) and 20 patients aged over 60 years (group O). We set three primary outcomes: difference in the interlamina height of the ligamentum flavum-dura mater complex (LFD) according to (1) age, (2) laterality, and (3) position. For secondary outcomes, the degree of ultrasonography visualization (poor, intermediate, or good) and the depths from the skin to LFD and to anterior complex were also measured on right and left paramedian sagittal oblique view in both lateral and sitting positions at L3/4, L4/5, and L5/S1 levels. All variables were analyzed in association with age, laterality, patient position, and spinal level.

RESULTS

The interlamina height of LFD was higher, and the degree of visualization was better in group Y than in group O. It differed depending on laterality in paramedian sagittal oblique view images in the same patients at all spinal levels. The interlamina height of LFD was the largest at L5/S1 level in both groups. Position had little influence on the interlamina height of LFD.

CONCLUSIONS

Scanning both sides and all spinal levels before selecting a puncture site for ultrasound-guided spinal anesthesia is recommended. The L5/S1 spinal level is a good option for spinal puncture in the elderly.

TRIAL REGISTRATION NUMBER

NCT03929874.

Effect of different fraction of inspired oxygen on development of atelectasis in mechanically ventilated children: A randomized controlled trial

BACKGROUND

The use of high fraction of inspired oxygen (F_I O₂ ) can cause direct pulmonary toxicity and pulmonary complications. The purpose of this study was to evaluate the effect of different F_I O₂ on development of intraoperative atelectasis in mechanically ventilated children using lung ultrasound.

METHODS

In this randomized controlled, patient- and sonographer-blinded trial, 86 children (≤6 years) undergoing noncardiac surgery were allocated into a low (n = 43) or high (n = 43) F_I O₂ group. The low F_I O₂ group consistently received 30% air-oxygen mixture during preoxygenation, ultrasound-guided recruitment maneuver, and mechanical ventilation. The high F_I O₂ group received 100% oxygen during preoxygenation and ultrasound-guided recruitment maneuver and 60% air-oxygen mixture during mechanical ventilation. Positive end-expiratory pressure of 5 cm H₂ O was applied in both groups. Lung ultrasound was performed one minute after the start of mechanical ventilation and at the end of surgery in both groups. Primary outcome was significant atelectasis incidence (consolidation score of ≥2 in any region) on the postoperative lung ultrasound. Secondary outcomes included significant atelectasis incidence on the preoperative lung ultrasound, incidences of intra- and postoperative desaturation, and incidences of postoperative fever and postoperative pulmonary complications.

RESULTS

Significant atelectasis incidence on the postoperative lung ultrasound was similar between the low and high F_I O₂ groups (28% vs 37%; Pearson chi-square value = 0.847; P = .357; OR 1.531; 95% CI 0.617-3.800). Significant atelectasis incidence on the preoperative lung ultrasound was also similar between the groups (12% vs 9%; Pearson chi-square value = 0.124; P = .725; OR 0.779; 95% CI 0.194-3.125). There were no statistically significant differences in the other secondary outcomes.

CONCLUSIONS

F_I O₂ did not affect significant atelectasis formation in mechanically ventilated children who received ultrasound-guided recruitment maneuver and positive end-expiratory pressure.

Fluid responsiveness in the pediatric population

It is challenging to predict fluid responsiveness, that is, whether the cardiac index or stroke volume index would be increased by fluid administration, in the pediatric population. Previous studies on fluid responsiveness have assessed several variables derived from pressure wave measurements, plethysmography (pulse oximeter plethysmograph amplitude variation), ultrasonography, bioreactance data, and various combined methods. However, only the respiratory variation of aortic blood flow peak velocity has consistently shown a predictive ability in pediatric patients. For the prediction of fluid responsiveness in children, flow- or volume-dependent, noninvasive variables are more promising than pressure-dependent, invasive variables. This article reviews various potential variables for the prediction of fluid responsiveness in the pediatric population. Differences in anatomic and physiologic characteristics between the pediatric and adult populations are covered. In addition, some important considerations are discussed for future studies on fluid responsiveness in the pediatric population.

Comparison of pulse pressure variation and pleth variability index in the prone position in pediatric patients under 2 years old

Background

The assessment of intravascular volume status is very important especially in children during anesthesia. Pulse pressure variation (PPV) and pleth variability index (PVI) are well known parameters for assessing intravascular volume status and fluid responsiveness. We compared PPV and PVI for children aged less than two years who underwent surgery in the prone position.

Methods

A total of 27 children were enrolled. We measured PPV and PVI at the same limb during surgery before and after changing the patients’ position from supine to prone. We then compared PPV and PVI at each period using Bland-Altman plot for bias between the two parameters and for any correlation. We also examined the difference between before and after the position change for each parameter, along with peak inspiratory pressure, heart rate and mean blood pressure.

Results

The bias between PPV and PVI was −2.2% with a 95% limits of agreement of −18.8% to 14.5%, not showing significant correlation at any period. Both PPV and PVI showed no significant difference before and after the position change.

Conclusions

No significant correlation between PVI and PPV was observed in children undergoing surgery in the prone position. Further studies relating PVI, PPV, and fluid responsiveness via adequate cardiac output estimation in children aged less than 2 years are required.

Accuracy of pulse oximeters at low oxygen saturations in children with congenital cyanotic heart disease: An observational study

BACKGROUND

Pulse oximetry overestimates arterial oxygen saturation (SaO₂ ) at less than 90% saturation in cyanotic children. The Masimo Blue sensor (Masimo Corp., Irvine, CA) is a pulse oximetry sensor developed for use in children with cyanosis. However, there remains a lack of research in actual clinical practice.

AIMS

We evaluated the intraoperative performance of three different pulse oximeters to measure oxyhemoglobin saturation (SpO₂ ) at low saturations in pediatric patients with cyanotic heart disease and the influence of clinical variables (SaO₂ , hemoglobin concentration, perfusion index, and weight) on the accuracy of the sensors.

METHODS

This prospective observational study compared SpO₂ measured using three pulse oximeters (Masimo Blue [Masimo Corp., Irvine, CA]; Masimo LNCS, and Nellcor [Medtronic, Dublin, Ireland]) at selected SaO₂ ranges (≥85%, 75%-84%, 60%-74%, and < 60%). Accuracy was evaluated according to bias and Bland-Altman analysis with appropriate correction for multiple measurements. Relationships between bias and clinical variables were assessed using a generalized estimating equation.

RESULTS

Two hundred and fifty-eight samples were analyzed. The mean overall bias (limits of agreement) of Masimo Blue, Masimo LNCS, and Nellcor sensor was -5.3 (-20.9 to 10.3%), -7.4 (-21.9 to 7.1%), and -7.4 (-22.5 to 15.1%), respectively. However, there was no difference in bias among the three sensors at SaO₂ <60%. Generalized estimating equation showed that SaO₂ value was associated with bias of all sensors. Perfusion index affected the bias of Blue sensor and LNCS sensor, and patients' weight was associated with bias of Nellcor sensor.

CONCLUSION

Masimo blue sensor demonstrated overall lower bias compared to the other two sensors. However, the accuracy of all sensors was similarly poor at SaO₂ less than 60%. Bias was influenced by SaO₂ , perfusion index, and body weight.

Taking a Stab at Quantifying the Energetics of Biological Puncture

An organism’s ability to control the timing and direction of energy flow both within its body and out to the surrounding environment is vital to maintaining proper function. When physically interacting with an external target, the mechanical energy applied by the organism can be transferred to the target as several types of output energy, such as target deformation, target fracture, or as a transfer of momentum. The particular function being performed will dictate which of these results is most adaptive to the organism. Chewing food favors fracture, whereas running favors the transfer of momentum from the appendages to the ground. Here, we explore the relationship between deformation, fracture, and momentum transfer in biological puncture systems. Puncture is a widespread behavior in biology requiring energy transfer into a target to allow fracture and subsequent insertion of the tool. Existing correlations between both tool shape and tool dynamics with puncture success do not account for what energy may be lost due to deformation and momentum transfer in biological systems. Using a combination of pendulum tests and particle tracking velocimetry (PTV), we explored the contributions of fracture, deformation and momentum to puncture events using a gaboon viper fang. Results on unrestrained targets illustrate that momentum transfer between tool and target, controlled by the relative masses of the two, can influence the extent of fracture achieved during high-speed puncture. PTV allowed us to quantify deformation throughout the target during puncture and tease apart how input energy is partitioned between deformation and fracture. The relationship between input energy, target deformation and target fracture is non-linear; increasing impact speed from 2.0 to 2.5 m/s created no further fracture, but did increase deformation while increasing speed to 3.0 m/s allowed an equivalent amount of fracture to be achieved for less overall deformation. These results point to a new framework for examining puncture systems, where the relative resistances to deformation, fracture and target movement dictate where energy flows during impact. Further developing these methods will allow researchers to quantify the energetics of puncture systems in a way that is comparable across a broad range of organisms and connect energy flow within an organism to how that energy is eventually transferred to the environment.

A pharmacodynamic model of respiratory rate and end-tidal carbon dioxide values during anesthesia in children

It is essential to monitor the end-tidal carbon dioxide (ETCO₂) during general anesthesia and adjust the tidal volume and respiratory rate (RR). For the purpose of this study, we used a population pharmacodynamic modeling approach to establish the relationship between RR versus ETCO₂ data during general anesthesia in children, and to identify the clinical variables affecting this relationship. A prospective observational study was designed to include 51 patients (aged ≤ 12 years), including users of antiepileptic drugs (levetiracetam, valproic, or phenobarbital (n = 21)) and non-users (n = 30), scheduled to receive general anesthesia during elective surgery. When the ETCO₂ was at 40 mmHg, the RR was adjusted 1 breath per every 2 min until the ETCO₂ was 30 mmHg and recovered to 40 mmHg. Pharmacodynamic analysis using a sigmoid E_max model was performed to assess the RR-ETCO₂ relationship. As RR varied from 3 to 37 breaths per minute, the ETCO₂ changed from 40 to 30 mmHg. Hysteresis between the RR and ETCO₂ was observed and accounted for when the model was developed. The C_e50 (RR to achieve 50% of maximum decrease in ETCO₂; i.e. 35 mmHg) was 20.5 in non-users of antiepileptic drugs and 14.9 in those on antiepileptic drug medication. The values of γ (the steepness of the concentration-response relation curve) and k_eo (the first-order rate constant determining the equilibration between the RR and ETCO₂) were 7.53 and 0.467 min^-1, respectively. The C_e50 and ETCO₂ data fit to a sigmoid E_max model. In conclusion, the RR required to get the target ETCO₂ was much lower in children patients taking antiepileptic drugs than that of non-user children patients during the general anesthesia.

Preparation and Optical Properties of Trivalent Erbium-Doped CaY₂O₄ Powders Under 980 nm Excitation

Nanocrystalline CaY₂O₄:Er³⁺ up-conversion phosphor was prepared by the sol-gel process. A homogeneous precursor sol was heated on a hot plate and then coagulated gel was prefired at 300 °C for 4 hr in Ar, followed by final annealing at 1,200 °C for 4 h in Ar. The crystallinity of the powders after annealing was confirmed using an X-ray diffraction analysis. The shape and particle size of the powders were observed by field emission-scanning electron microscope and transmission electron microscope. Up-conversion luminescence spectra were recorded with a fluorescent spectrophotometer under a 980-nm excitation. The dependence of the up-converted intensities on pumping powers for powders was obtained by changing the excitation powers at room temperature. X-ray diffraction patterns confirmed the presence of single orthorhombic crystalline CaY₂O₄ and no impurity peaks were identified. Micrographical images of 3 mol%-doped CaY₂O₄ powder indicates that the particle size is uniform, and ranges from 100~200 nm. Up-conversion efficiency is the highest when the doping concentration of Er³⁺ is 3 mol%.

Manual vs pressure-controlled facemask ventilation during the induction of general anesthesia in children: A prospective randomized controlled study

BACKGROUND

Gastric insufflation frequently occurs during facemask ventilation in children. In the present study, we compared the incidence of gastric insufflation between pressure-controlled facemask ventilation and manual facemask ventilation during general anesthesia induction in children.

METHODS

Children in the pressure-controlled ventilation group (n = 76) received pressure-controlled facemask ventilation at an inspiratory pressure of 13 cm H₂ O. In the manual ventilation group (n = 75), facemask ventilation was manually performed by anesthesiologists, who tried to maintain an inspiratory pressure of 13 cm H₂ O. The adjustable pressure limiting valve was set at 13 cm H₂ O. The incidence of gastric insufflation during 90 seconds after the initiation of ventilation was assessed using epigastric auscultation and gastric ultrasonography.

RESULTS

The incidence of gastric insufflation was significantly higher in the manual  facemask ventilation group than in the pressure-controlled ventilation group (48% vs 12%, respectively; odds ratio 7.78, 95% confidence interval [CI] 3.38-17.9; P < 0.001). The mean peak airway pressure during ventilation was significantly higher in the manual ventilation group than in the pressure-controlled ventilation group (16.1 [3.0] cm H₂ O vs 13.0 [0.1] cm H₂ O; 95% CI of differences, 2.36-3.71 cm H₂ O; P < 0.001). The manual ventilation group exhibited a wide peak airway pressure  range (11-26 cm H₂ O) and a wide variation of tidal volume (0-7.0 mL/kg) compared with those of the pressure-controlled ventilation group (13-14 cm H₂ O and 0.6-16.0 mL/kg, respectively).

CONCLUSION

At an inspiratory pressure of 13 cm H₂ O, pressure-controlled ventilation may be more effective than manual ventilation in preventing gastric insufflation while providing stable ventilation in children.

Phase-Only Rotation Invariant Correlation Using Synthesized Phase Objects

We present a development of the method of synthesized phase objects (SPO-method) (P. V. Yezhov, et al. Opt. Exp. 20, 29854 (2012)) for the phase-only rotation invariant pattern recognition. It has been performed a comparison of correlation signals for a set of amplitude objects under their rotation by using the standard and SPO methods, by applying the Fourier-Mellin transformation. The results of both calculation and optical experiments carried out using an optical-digital correlator with SLM in the Fourier plane have been presented.

Comparison of bupivacaine plus intrathecal fentanyl and bupivacaine alone for spinal anesthesia with intravenous dexmedetomidine sedation: a randomized, double-blind, noninferiority trial

BACKGROUND AND OBJECTIVES

Fentanyl is widely used as an intrathecal adjuvant to local anesthetics to enhance the duration of spinal anesthesia. Recent evidence suggests that intravenous dexmedetomidine prolongs the duration of spinal anesthesia. This noninferiority study evaluated whether bupivacaine alone could provide a noninferior duration of block compared with bupivacaine and fentanyl when intravenous dexmedetomidine was administered intraoperatively.

METHODS

Fifty-six patients scheduled for total knee arthroplasty under spinal anesthesia were randomly allocated to receive either bupivacaine 13 mg with intrathecal fentanyl 20 µg (Group BF) or bupivacaine 13 mg (Group B). Both groups underwent intravenous dexmedetomidine sedation throughout the surgery (1 µg kg^-1 for 10 min, followed by 0.5 µg kg^-1 h^-1). The primary outcome was the time to two-segment regression of the sensory block. The noninferiority margin for the mean difference was predefined as -10 min. Secondary outcomes included postoperative pain scores, analgesics consumptions, and the incidences of pruritus, nausea, and vomiting.

RESULTS

There was no significant difference in the two-segment regression time of sensory block (Group B 109.1±25.0 min vs Group BF 104.3±25.9 min; p=0.484). The mean difference in the two-segment regression time between the 2 groups was 4.8 min (95 % CI -8.9 to 18.6), demonstrating the noninferiority of bupivacaine alone. Secondary outcomes showed no significant differences between the two groups.

CONCLUSIONS

The duration of spinal anesthesia with bupivacaine alone is noninferior to that of bupivacaine plus fentanyl in patients receiving intravenous dexmedetomidine intraoperatively. Our results suggest that intrathecal fentanyl may not be required when intravenous dexmedetomidine is administered.

TRIAL REGISTRATION NUMBER

NCT03105115.

Remifentanil vs. Lignocaine for Attenuating the Haemodynamic Response during Rapid Sequence Induction Using Propofol: Double-Blind Randomised Clinical Trial

This study was conducted to determine whether lignocaine or remifentanil effectively attenuate the response to endotracheal intubation during rapid sequence induction. Forty-eight patients were randomly divided into three groups: Group NS (n=16) received normal saline 0.1 ml/kg, Group L (n=16) received lignocaine 1.5 mg/kg, and Group R (n=16) received remifentanil 1 /μg/kg. Anaesthesia was induced with propofol 2 mg/kg after glycopyrrolate 0.2 mg IV. Each study drug was given intravenously over 30 seconds after loss of consciousness. Cricoid pressure was applied until intubation. Succinylcholine 1.0 mg/kg was administered to facilitate tracheal intubation. After intubation, the patient's lungs were ventilated with sevoflurane 1% and nitrous oxide 50% in oxygen. Mean arterial pressure and heart rate were recorded before induction, at loss of consciousness, immediately before laryngoscopy and every minute after intubation for 10 minutes. Mean arterial pressure fell following propofol in all groups. The maximum increase in mean arterial pressure in Group NS and Group L were 46% and 38% respectively above the baseline value one minute after intubation, whereas the mean arterial pressure in Group R increased only back to the baseline value. Heart rate in Group NS and Group L were increased by 27% and 33% above baseline value respectively one minute after intubation, while that in Group R was increased only to the baseline value. The results indicate that remifentanil 1 μg/kg, but not lignocaine 1.5 mg/kg, effectively attenuates the haemodynamic response to endotracheal intubation during rapid sequence induction using propofol.