The influence of preoperative epidural labor analgesia on postoperative pain in parturients undergoing emergency cesarean section : A retrospective analysis.

BACKGROUND: Intense noxious input from the periphery may result in central sensitization and hyperexcitability, thus accentuating subsequent postoperative pain. Parturients who undergo emergency cesarean section (C-sec) after experiencing labor pain often develop labor pain-induced sensitization. OBJECTIVE: This retrospective study evaluated whether parturients without epidural labor analgesia (ELA) who underwent emergency C­sec, experienced more severe postoperative pain and required more rescue analgesics during the postoperative period. METHODS: The institution's medical database was searched for parturients who underwent emergency C­sec under spinal anesthesia for any reason between January 2013 and December 2016. Those who underwent elective C­sec under spinal anesthesia were included as the reference arm. Parturients were divided into three groups: ELA, no-ELA and elective. Characteristics of patients and perioperative outcomes were evaluated. As primary outcomes, numerical rating scale (NRS) for postoperative pain (0-10) was recorded up to 96 h postoperatively, and use of rescue analgesics was evaluated at 6, 24, and 48 h postoperatively. RESULTS: In the ELA, no-ELA, and elective groups, 61, 73, and 88 parturients, respectively, were ultimately enrolled. The NRS for pain were similar among the three groups, except at 6 h postoperatively. Parturients in the no-ELA group demonstrated significantly higher NRS at 6 h postoperatively than those in the ELA group (P = 0.01).More patients in the no-ELA group required rescue analgesics than in the ELA (P = 0.001) and elective groups (P < 0.001) at 6-24 h postoperatively. Moreover, the proportion of patients requiring rescue analgesics ≥2 times was also significantly higher in the no-ELA group (vs. the ELA group, P = 0.004; vs. the elective group, P < 0.001). CONCLUSION: Parturients undergoing emergency C­sec without ELA management during labor experienced greater postoperative pain and a greater use of rescue analgesics during the postoperative period. The findings suggest that administration of ELA before emergency C­sec may act as pre-emptive analgesia against postoperative pain.

Evidence for a Field-Induced Quantum Spin Liquid in α-RuCl_{3}.

We report a ^{35}Cl nuclear magnetic resonance study in the honeycomb lattice α-RuCl_{3}, a material that has been suggested to potentially realize a Kitaev quantum spin liquid (QSL) ground state. Our results provide direct evidence that α-RuCl_{3} exhibits a magnetic-field-induced QSL. For fields larger than ∼10 T, a spin gap opens up while resonance lines remain sharp, evidencing that spins are quantum disordered and locally fluctuating. The spin gap increases linearly with an increasing magnetic field, reaching ∼50 K at 15 T, and is nearly isotropic with respect to the field direction. The unusual rapid increase of the spin gap with increasing field and its isotropic nature are incompatible with conventional magnetic ordering and, in particular, exclude that the ground state is a fully polarized ferromagnet. The presence of such a field-induced gapped QSL phase has indeed been predicted in the Kitaev model.

Anomalous Thermal Conductivity and Magnetic Torque Response in the Honeycomb Magnet α-RuCl_{3}.

We report on the unusual behavior of the in-plane thermal conductivity κ and torque τ response in the Kitaev-Heisenberg material α-RuCl_{3}. κ shows a striking enhancement with linear growth beyond H=7 T, where magnetic order disappears, while τ for both of the in-plane symmetry directions shows an anomaly at the same field. The temperature and field dependence of κ are far more complex than conventional phonon and magnon contributions, and require us to invoke the presence of unconventional spin excitations whose properties are characteristic of a field-induced spin-liquid phase related to the enigmatic physics of the Kitaev model in an applied magnetic field.

Magnetic Excitations and Continuum of a Possibly Field-Induced Quantum Spin Liquid in α-RuCl_{3}.

We report on terahertz spectroscopy of quantum spin dynamics in α-RuCl_{3}, a system proximate to the Kitaev honeycomb model, as a function of temperature and magnetic field. We follow the evolution of an extended magnetic continuum below the structural phase transition at T_{s2}=62 K. With the onset of a long-range magnetic order at T_{N}=6.5 K, spectral weight is transferred to a well-defined magnetic excitation at ℏω_{1}=2.48 meV, which is accompanied by a higher-energy band at ℏω_{2}=6.48 meV. Both excitations soften in a magnetic field, signaling a quantum phase transition close to B_{c}=7 T, where a broad continuum dominates the dynamical response. Above B_{c}, the long-range order is suppressed, and on top of the continuum, emergent magnetic excitations evolve. These excitations follow clear selection rules and exhibit distinct field dependencies, characterizing the dynamical properties of a possibly field-induced quantum spin liquid.

Magnesium sulphate attenuates acute postoperative pain and increased pain intensity after surgical injury in staged bilateral total knee arthroplasty: a randomized, double-blinded, placebo-controlled trial.

BACKGROUND: We evaluated the effect of magnesium sulphate on increased pain in 44 patients undergoing staged bilateral total knee arthroplasty (TKA). METHODS: The magnesium group (n=22) and the control group (n=22) received magnesium sulphate and isotonic saline, respectively, throughout the surgery. Postoperative pain (visual analogue scale, VAS) at rest and the amounts of patient-controlled analgesia (PCA, fentanyl) and rescue analgesia (ketoprofen) administered during the first 48 h were compared between the two groups and within each group between the first and second TKA. RESULTS: The VAS scores were significantly higher in the control group than in the magnesium group not only after the first TKA [29 (11) vs 19 (9) at 24 h and 33 (8) vs 24 (10) at 48 h; P=0.001] but also after the second TKA [44 (17) vs 20 (10) at 24 h and 43 (14) vs 25 (10) at 48 h; P<0.001]. In the control group, VAS scores were significantly higher for the second than for the first operated knee [44 (17) vs 29 (11) at 24 h and 43 (14) vs 33 (8) at 48 h; P<0.001 and P=0.006, respectively]. In the magnesium group, there were no significant differences in VAS scores between the first and second TKA. Magnesium significantly reduced the amounts of rescue analgesics and fentanyl administered over the first 48 h postoperatively. CONCLUSIONS: Magnesium sulphate administration significantly reduced postoperative pain and minimized the difference in pain intensity between the first and second operations. CLINICAL TRIAL REGISTRATION: KCT0001361.

Prospective, randomized and controlled trial on magnesium sulfate administration during laparoscopic gastrectomy: effects on surgical space conditions and recovery profiles.

BACKGROUND: The degree of neuromuscular blockade is one of the important factors that determine the condition of surgical space during laparoscopic surgery. Magnesium sulfate potentiates the actions of neuromuscular blocking agent, and we hypothesized that intraoperative magnesium sulfate infusion may improve surgical space condition during laparoscopic surgery. METHODS: Eighty-four patients undergoing elective laparoscopic gastrectomy were randomized to receive isotonic saline (group C) or magnesium sulfate (group M, loading dose with 50 mg/kg over 10 min and then 15 mg/kg/h by continuous infusion) to maintain the moderate neuromuscular blockade using rocuronium. Two experienced surgeons scored the quality of surgical space condition using a 5-point surgical rating scale (SRS). The secondary outcomes included recovery profiles, postoperative pain and adverse events. RESULTS: The SRS in group M was higher than that of group C. The proportion of patients with a SRS of 5 (optimal) was 2.7 % in the group C and 40.5 % in the group M (P < 0.0001) although a lower amount of rocuronium was required in group M than group C [24.2 (6.5) mg/h for group M vs. 27.5 (6) mg/h for group C; P = 0.017]. Pain after operation site was less severe in group M than in group C at postoperative 24 h (P = 0.009). Recovery profiles and adverse events were similar between the two groups. CONCLUSION: Intraoperative administration of magnesium sulfate improved the quality of surgical space conditions and decreased neuromuscular blocking agent requirement and postoperative pain in patients undergoing laparoscopic gastrectomy.

The effect of tranexamic acid on blood coagulation in total hip replacement arthroplasty: rotational thromboelastographic (ROTEM®) analysis.

We evaluated changes in rotational thromboelastometry (ROTEM(®) ) parameters and clinical outcomes in patients undergoing total hip replacement arthroplasty, with concomitant infusions of tranexamic acid and of 6% hydroxyethyl starch 130/0.4. Fifty-five patients were randomly assigned to either the tranexamic acid (n = 29) or the control (n = 26) group. Hydroxyethyl starch was administered in the range of 10-15 ml.kg(-1) during the operation in both groups. In the control group, the clot formation time and maximum clot firmness of APTEM showed significant differences when compared with those of EXTEM at one hour postoperatively, suggestive of fibrinolysis. In the tranexamic acid group, there was no significant difference between each postoperative EXTEM and APTEM parameter. In the tranexamic acid and control group, postoperative blood loss was 308 ml (210-420 [106-745]) and 488 ml (375-620 [170-910], p = 0.002), respectively, and total blood loss was 1168 ml (922-1470 [663-2107]) and 1563 ml (1276-1708 [887-1494], p = 0.003). Haemoglobin concentration was higher in the tranexamic acid group on the second postoperative day (10.5 (9.4-12.1 [7.9-14.0]) vs. 9.6 (8.9-10.5[7.3-16.0]) g.dl(-1) , p = 0.027). In patients undergoing total hip replacement arthroplasty, postoperative fibrinolysis aggravated by hydroxyethyl starch was attenuated by co-administration of 10 mg.kg(-1) tranexamic acid, which may have led to less postoperative blood loss.

The effects of acute normovolaemic haemodilution on peri-operative coagulation in total hip arthroplasty.

Total hip arthroplasty results in substantial blood loss in the peri-operative period. We evaluated the effects of acute normovolaemic haemodilution on blood coagulation and platelet function in 11 patients undergoing total hip arthroplasty. We performed acute normovolaemic haemodilution and haematological tests, rotational thromboelastometry (ROTEM(®) ) and whole-blood impedance aggregometry. Blood samples were obtained at three time points: (i) before the initiation of acute normovolaemic haemodilution; (ii) 20 min after completion of acute normovolaemic haemodilution; and (iii) 20 min after retransfusion. After acute normovolaemic haemodilution, ROTEM parameters demonstrated hypocoagulability. Clot formation time of INTEM was increased by 31.6% (p = 0.016), whereas the α-angle and maximum clot formation of INTEM decreased by 8.1% (p = 0.032) and 3.0% (p = 0.013) respectively, compared with baseline values. Clotting time and clot formation time of EXTEM were increased by 40.8% (p = 0.042) and 31.3% (p = 0.016), respectively, whereas the α-angle and maximum clot formation of EXTEM were decreased by 11.9% (p = 0.020) and 9.5% (p = 0.013), respectively. The maximum clot formation of FIBTEM decreased by 35.1% compared with the baseline value (p = 0.007). Following retransfusion, ROTEM values returned to baseline; clot formation time decreased and the α-angle and maximum clot formation increased. There were no significant changes in platelet aggregation during the study. At 20 min after the end of acute normovolaemic haemodilution, the international normalised ratio of prothrombin time was increased compared with the baseline value (p = 0.003). We conclude that acute normovolaemic haemodilution resulted in a hypocoagulable state compared with baseline values and that coagulation parameters returned to normal after retransfusion.

Timing of reversal with respect to three nerve stimulator end-points from cisatracurium-induced neuromuscular block.

After elective ear surgery with cisatracurium neuromuscular blockade, 48 adults were randomly assigned to receive neostigmine: (a) at appearance of the fourth twitch of a 'train-of-four'; (b) at loss of fade to train-of-four; or (c) at loss of fade to double-burst stimulation, all monitored using a TOF-Watch SX® on one arm. For each of these conditions, the recovery from train-of-four (TOF) ratio was measured in parallel objectively using a TOF-Watch SX placed on the contralateral arm. The median (IQR [range]) time from administration of reversal to a train-of-four ratio ≥ 0.9 was 11 (9-15.5 [2-28]) min, 8 (4-13.5 [1-25]) min and 7 (4-10 [2-15]) min in the three groups, respectively. This recovery time was significantly shorter when reversal was given at loss of fade to double-burst stimulation (c), than when given at the appearance of the fourth twitch (a), p = 0.046. However, the total time to extubation may be unaffected as it takes longer for fade to be lost after double-burst stimulation than for four twitches subjectively to appear.

Effects of magnesium sulphate on coagulation after laparoscopic colorectal cancer surgery, measured by rotational thromboelastometry (ROTEM® ).

We investigated the effects of magnesium sulphate on blood coagulation profiles using rotational thromboelastometry in patients undergoing laparoscopic colorectal cancer surgery. Patients were randomly allocated to the magnesium group (n = 22) or control group (n = 22). The magnesium group received intravenous magnesium sulphate (50 mg.kg(-1) followed by a continuous infusion of 15 mg.kg(-1) .h(-1) ), whereas the control group received the same volume of isotonic saline. Mean (SD) postoperative serum magnesium levels were 1.60 (0.13) mmol.l(-1) in the magnesium group compared with 0.98 (0.06) mmol.l(-1) in the control group (p < 0.001). All maximum clot firmness values of ROTEM analysis were significantly lower on the third postoperative day in the magnesium group compared with the control group (p < 0.05). We conclude that ROTEM analysis demonstrated that intra-operative administration of intravenous magnesium sulphate reduces blood hypercoagulability in patients undergoing laparoscopic colorectal cancer surgery.

Efficacy of butylscopolamine for the treatment of catheter-related bladder discomfort: a prospective, randomized, placebo-controlled, double-blind study.

BACKGROUND: Catheter-related bladder discomfort (CRBD) secondary to intraoperative catheterization of urinary bladder is one of the most distressing symptoms during recovery from anaesthesia. Butylscopolamine, a peripheral antimuscarinic agent, is effective for relieving the pain, which is because of smooth muscle contraction. The aim of this study was to assess the efficacy and safety profiles of butylscopolamine in treating CRBD after urological surgeries. METHODS: Adult male patients undergoing urological surgery requiring urinary bladder catheterization intraoperatively were enrolled. Induction and maintenance of anaesthesia were standardized. Patients were randomized into two groups after complaining of CRBD in the post-anaesthesia care unit. The control group (n=29) received normal saline and the butylscopolamine group (n=28) was administered butylscopolamine 20 mg i.v. The severity of CRBD, postoperative pain, and adverse effects were assessed at baseline, 20 min, 1, 2, and 6 h after administration of the study drug. RESULTS: The severity of CRBD observed in the butylscopolamine group was significantly lower than that of the control group at 1, 2, and 6 h after administration of the study drug [59 (12), 50 (16), 40 (21) in the control group vs 41 (22), 32 (25), 23 (18) in the butylscopolamine group, P<0.01]. Rescue analgesics were required less in the butylscopolamine group than in the control group (P=0.001). Adverse events were comparable between the two groups. CONCLUSION: Butylscopolamine 20 mg administered i.v. after complaining CRBD during recovery reduced both the severity of CRBD and the need for rescue analgesics without adverse effects in patients undergoing urologic surgeries.

Emergence agitation in children undergoing adenotonsillectomy: a comparison of sevoflurane vs. sevoflurane-remifentanil administration.

BACKGROUND: Sevoflurane is widely used in paediatric anaesthesia but frequently causes emergence agitation (EA). This study evaluated whether limiting the sevoflurane concentration by combining remifentanil with sevoflurane reduced the incidence of EA. METHODS: Eighty-four preschool children scheduled for adenotonsillectomy were randomly assigned to either the remifentanil or sevoflurane group. In the remifentanil group, anaesthesia was induced with thiopental, rocuronium, and 1% sevoflurane. It was maintained with 1% sevoflurane, 60% nitrous oxide in oxygen, and a continuous infusion of remifentanil. For the sevoflurane group, anaesthesia was induced with thiopental, rocuronium, and 8% sevoflurane, and was maintained with 2-3% sevoflurane. Both groups received ketorolac 1 mg/kg and dexamethasone 0.15 mg/kg. EA was measured using the paediatric anaesthesia emergence delirium (PAED) scale and a four-point EA scale in the post-anaesthesia care unit. RESULTS: The scores on the PAED scales were significantly lower in the remifentanil group than in the sevoflurane group [median (interquartile range); 6 (4.25-10.25) vs. 11 (7.75-14.0), P = 0.007], and the proportion of patients with PAED scores ≥ 10 was significantly lower in the remifentanil group than in the sevoflurane group [15 (35.7%) vs. 27 (64.2%), P = 0.009]. The incidence of EA evaluated using the four-point scale was also lower in the remifentanil group [11 (26.1%) vs. 21 (50%), respectively, P = 0.025]. CONCLUSION: The incidence of EA was lower in children undergoing adenotonsillectomy who received a lower concentration of sevoflurane combined with remifentanil than in those given a higher concentration of sevoflurane without remifentanil.

Rotational thromboelastometry during Cesarean section as a predictive evaluation for the progression of persistent postpartum hemorrhage in parturients with placenta previa: A prospective observational study.

Background: The rotational thromboelastogram (ROTEM) has been used in the management of massive bleeding and transfusion strategy. This study investigated ROTEM parameters measured during Cesarean section as predictors for the progression of persistent postpartum hemorrhage (PPH) in parturients with placenta previa. Methods: This prospective observational study recruited 100 women scheduled for elective Cesarean section after being diagnosed with placenta previa. Recruited women were divided into two groups according to the amount of estimated blood loss: the PPH group (PPH > 1500 ml) vs. the non-PPH group. ROTEM with laboratory tests was performed three times, preoperative, intraoperative, and postoperative time, which were compared between the two groups. Results: The PPH and non-PPH groups included 57 and 41 women, respectively. The area under the receiver-operating characteristic curve of postoperative FIBTEM A5 to detect PPH was 0.76 (95% CI = 0.64 to 0.87; P < 0.001). When postoperative FIBTEM A5 was 9.5, the sensitivity and specificity were 0.74 (95% CI = 0.55 to 0.88) and 0.73 (95% CI = 0.57 to 0.86), respectively. When subgrouping the PPH group based on the postoperative FIBTEM A5 value of 9.5, intraoperative cEBL was similar between the two subgroups; however, postoperative RBC was transfused more in the subgroup with FIBTEM A5 < 9.5 than the subgroup with FIBTEM A5 ≥ 9.5 (7.4 ± 3.0 vs 5.1 ± 2.3 units, respectively; P = 0.003). Conclusion: Postoperative FIBTEM A5, with appropriate selection of the cut-off value, can be a biomarker for more prolonged PPH and massive transfusion following Cesarean section by placenta previa.

Kondo screening in a Majorana metal.

Kondo impurities provide a nontrivial probe to unravel the character of the excitations of a quantum spin liquid. In the S = 1/2 Kitaev model on the honeycomb lattice, Kondo impurities embedded in the spin-liquid host can be screened by itinerant Majorana fermions via gauge-flux binding. Here, we report experimental signatures of metallic-like Kondo screening at intermediate temperatures in the Kitaev honeycomb material α-RuCl3 with dilute Cr3+ (S = 3/2) impurities. The static magnetic susceptibility, the muon Knight shift, and the muon spin-relaxation rate all feature logarithmic divergences, a hallmark of a metallic Kondo effect. Concurrently, the linear coefficient of the magnetic specific heat is large in the same temperature regime, indicating the presence of a host Majorana metal. This observation opens new avenues for exploring uncharted Kondo physics in insulating quantum magnets.

Effects of pregabalin on the activity of glutamate transporter type 3.

BACKGROUND: Pregabalin, (S)-3-aminomethyl-5-methyl hexanoic acid, is a ligand for the α2δ subunit (a component of voltage-gated calcium channels) and has analgesic and anticonvulsant properties. Glutamate uptake by glutamate transporters may be a mechanism for these properties. We investigated the effects of pregabalin on the activity of the neuronal glutamate transporter type 3 (EAAT3). METHODS: EAAT3 was expressed in Xenopus laevis oocytes. Two-electrode voltage clamping was used to record membrane currents before, during, and after applying l-glutamate (30 µM) in the presence or absence of pregabalin. Currents were also measured in oocytes pretreated with a protein kinase C (PKC) activator (phorbol-12-myristate-13-acetate, PMA), PKC inhibitors (chelerythrine or staurosporine), or a phosphatidylinositol-3-kinase (PI3K) inhibitor wortmannin. RESULTS: The exposure of the oocytes injected with EAAT3 mRNA to serial concentrations of pregabalin (0.06-60 µM) significantly increased their responses to 30 µM l-glutamate. A kinetic study showed that pregabalin significantly increased V(max) without changing K(m). Treatment of oocytes with PMA, pregabalin, or pregabalin plus PMA significantly increased transporter currents vs controls, but treatment with PMA plus pregabalin did not increase the responses further vs PMA or pregabalin alone. In addition, pretreatment of oocytes with two PKC inhibitors (chelerythrine or staurosporine), or inhibitor wortmannin, significantly reduced basal and pregabalin-enhanced EAAT3 activity. CONCLUSIONS: Pregabalin increased EAAT3 activity and PKC and PI3K were involved. This may explain the analgesic effect of pregabalin in neuropathic pain.

Effects of valproic acid and magnesium sulphate on rocuronium requirement in patients undergoing craniotomy for cerebrovascular surgery.

BACKGROUND: Many anti-epileptics cause resistance to non-depolarizing neuromuscular blocking agents, but this has not been reported for valproic acid (VPA). We hypothesized that VPA would increase the rocuronium requirement and that magnesium sulphate (MgSO(4)) may reduce this increase. METHODS: Fifty-five patients undergoing cerebrovascular surgeries were studied. Subjects were allocated into three groups at a 1:1:1 ratio: Groups VM, VC, and C. Groups VM and VC were given VPA premedication; Group C was not. A rocuronium injection (0.6 mg kg(-1) i.v.) was administered to Group VM, followed by MgSO(4) as a 50 mg kg(-1) i.v. bolus and 15 mg kg(-1) h(-1) infusion. The same volume of 0.9% saline was administered to the other groups. Supplementary rocuronium (0.15 mg kg(-1)) was given whenever the train-of-four count reached 2. Rocuronium requirements (primary outcome), mean arterial pressure (MAP), heart rate (HR), nausea, vomiting, shivering, and use of anti-emetics and nicardipine were compared. RESULTS: Group VC showed the highest rocuronium requirement [mg kg(-1) h(-1): 0.47 (0.08) vs 0.33 (0.12) (Group C), 0.31 (0.07) (Group VM); P<0.001]. MAP, intraoperative HR, nausea, vomiting, shivering, and use of anti-emetics and nicardipine were not significantly different among the groups. Postoperative HR was lower in Group VM than in Group VC. CONCLUSIONS: VPA increased the rocuronium requirement, and MgSO(4) infusion attenuated this increase.

Randomized double-blind study of remifentanil and dexmedetomidine for flexible bronchoscopy.

BACKGROUND: The safety profiles and efficacies of remifentanil and dexmedetomidine (a sedative-analgesic without respiratory depression) for sedation during flexible bronchoscopy were investigated. METHODS: Seventy-two patients undergoing elective flexible bronchoscopy were randomly assigned to a propofol-remifentanil group (Group PR, n=36) or a propofol-dexmedetomidine group (Group PD, n=36). The primary outcome was the incidence of oxygen desaturation. Haemodynamic variables, adverse events, need of oral cavity suction, cough scores, satisfaction scores of patients and bronchoscopists, levels of sedation, and recovery times were also compared. RESULTS: The incidence of oxygen desaturation was significantly lower in the PD group than in the PR group (P=0.01). There were no significant differences between groups in terms of level of sedation, oxygen saturation, mean arterial pressure, heart rate over time, cough scores, or patient satisfaction scores (P>0.05). However, cough scores and bronchoscopist satisfaction scores (P<0.01) were lower in the PD group. In addition, topical anaesthesia (P<0.01) was required more frequently and recovery time (P=0.00) was significantly longer in the PD group. However, oral suction (P=0.03) was required less frequently in the PD group. CONCLUSIONS: Dexmedetomidine was associated with fewer incidents of oxygen desaturation and a reduced need for oral cavity suction than remifentanil during flexible bronchoscopy. However, dexmedetomidine was associated with a longer recovery time and poorer bronchoscopist satisfaction score.

Drug-administration sequence of target-controlled propofol and remifentanil influences the onset of rocuronium. A double-blind, randomized trial.

BACKGROUND: Remifentanil is known to cause bradycardia and hypotension, as well as the decreases of cardiac output (CO). We hypothesized that hemodynamic suppression by remifentanil would affect the onset time of rocuronium. This study investigated whether the onset of rocuronium was influenced by the drug-administration sequence during induction of anesthesia with target-controlled infusion of propofol and remifentanil. METHODS: Healthy adult patients (n = 126) undergoing elective surgery under general anesthesia were randomized into two groups according to drug-administration sequence. In Remi-Pro-Rocu group (n = 62), remifentanil was infused first, followed by propofol. Then, rocuronium was administered lastly. In Pro-Rocu-Remi group (n = 64), propofol, rocuronium, and remifentanil were given in that order. As a primary outcome, the onset time of rocuronium was measured. Mean arterial pressure (MAP), heart rate (HR), CO, and stroke volume were recorded before anesthesia (T1), at injection of rocuronium (T2), immediately before and after intubation (T3 and T4). RESULTS: In Remi-Pro-Roc group, the onset of rocuronium was delayed significantly compared with Pro-Rocu-Remi group [median (interquartile range); 130 (105-150) vs. 90 (71-100) s, P < 0.001]. At the time of rocuronium injection (T2), MAP, HR, and CO were significantly lower in Remi-Pro-Rocu group than Pro-Rocu-Remi group (P < 0.001). CONCLUSION: The onset time of rocuronium is prolonged significantly by early administration of remifentanil during target-controlled infusion of propofol and remifentanil, and it may be due to the decreased CO caused by remifentanil.

A randomised controlled trial comparing rocuronium priming, magnesium pre-treatment and a combination of the two methods.

We investigated whether magnesium sulphate combined with rocuronium priming shortens the onset of neuromuscular blockade, compared with these methods used alone. Ninety-two patients scheduled for general anaesthesia were randomly allocated to one of four groups: controls were given 0.6 mg.kg(-1) rocuronium; patients in the prime group were given 0.06 mg.kg(-1) rocuronium three minutes before a further dose of 0.54 mg.kg(-1) rocuronium; patients in the magnesium group were given an infusion of 50 mg.kg(-1) magnesium sulphate before rocuronium and patients in the magnesium and prime group were given both the magnesium sulphate and the priming dose of rocuronium. Tracheal intubation was attempted 40 s after the rocuronium injection. The time to onset of neuromuscular blockade was the primary outcome; duration of blockade and tracheal intubating conditions were also measured. The group allocation and study drugs were coded and concealed until statistical analyses were completed. The magnesium and prime group had the shortest mean (SD) onset time (55 (16)s; p < 0.001), and best tracheal intubating conditions (p < 0.05). No statistical difference was found for the duration of blockade. As for adverse events, a burning or heat sensation was reported in eight (35%) and six (26%) patients in the magnesium and magnesium and prime groups, respectively. The combination of magnesium sulphate and rocuronium priming accelerated the onset or neuromuscular blockade and improved rapid-sequence intubating conditions, compared with either magnesium sulphate or priming used alone.