The optimal exhaled concentration of sevoflurane for intubation without neuromuscular blockade using clinical bolus doses of remifentanil: A randomized controlled trial

BACKGROUND: The aim of this study was to investigate the optimal exhaled sevoflurane concentration that produces adequate endotracheal intubation conditions when sevoflurane is combined with the different bolus doses of remifentanil used in clinical practice. METHODS: The patients were randomized to 3 groups (groups 1.0, 1.5, and 2.0), receiving remifentanil bolus doses of 1.0, 1.5, and 2.0 μg/kg, respectively. For each group, the concentration of sevoflurane used for each consecutive patient was increased or decreased using the "up-and-down" method based on the success or failure to achieve adequate conditions for intubation in the previous patient. The remifentanil bolus dose was administered 90 s before intubation and after the target sevoflurane concentration was achieved. RESULTS: In groups 1.0, 1.5, and 2.0, the effective concentration in 50% (EC50) of the sevoflurane concentration required to perform successful intubation was 3.0, 2.0, and 1.29 vol% and the effective concentration in 95% was 3.45, 2.91, and 1.89 vol%, respectively. When sevoflurane was administered for the induction, the increase in heart rate (HR) of group 1.0 was the highest among the groups. The highest number of adverse events occurred in group 2.0, including vocal cord rigidity, hypotension, and bradycardia. DISCUSSION: The EC50 of the sevoflurane concentration was 3.0, 2.0, and 1.29 vol% when it was combined with a bolus dose of remifentanil of 1.0, 1.5, and 2.0 μg/kg, respectively. Of the 3 different bolus doses of remifentanil, the dose of 1.5 μg/kg was least associated with changes in the HR/mean blood pressure during intubation without increasing adverse effects.ope

Comparison of Postoperative Pain and Adverse Effects between Variable-Rate Feedback Infusion and Conventional Fixed-Rate Basal Infusion Modes of Patient-Controlled Epidural Analgesia following Open Gastrectomy: A Randomized Controlled Trial

Patient-controlled epidural analgesia is widely used to control postoperative pain following major intra-abdominal surgeries. However, determining the optimal infusion dose that can produce effective analgesia while reducing side effects remains a task to be solved. Postoperative pain and adverse effects between variable-rate feedback infusion (VFIM group, n = 36) and conventional fixed-rate basal infusion (CFIM group, n = 36) of fentanyl/ropivacaine-based patient-controlled epidural analgesia were evaluated. In the CFIM group, the basal infusion rate was fixed (5 mL/h), whereas, in the VFIM group, the basal infusion rate was increased by 0.5 mL/h each time a bolus dose was administered and decreased by 0.3 mL/h when a bolus dose was not administered for 2 h. Patients in the VFIM group experienced significantly less pain at one to six hours after surgery than those in the CFIM group. Further, the number of patients who suffered from postoperative nausea was significantly lower in the VFIM group than in the CFIM group until six hours after surgery. The variable-rate feedback infusion mode of patient-controlled epidural analgesia may provide better analgesia accompanied with significantly less nausea in the early postoperative period than the conventional fixed-rate basal infusion mode following open gastrectomy.ope

Relationship between paravertebral muscle twitching and long-term effects of radiofrequency medial branch neurotomy

Background: To achieve a prolonged therapeutic effect in patients with lumbar facet joint syndrome, radiofrequency medial branch neurotomy (RF-MB) is commonly performed. The purpose of this study was to evaluate the prognostic value of paravertebral muscle twitching when performing RF-MB in patients with lumbar facet joint syndrome. Methods: We collected and analyzed data from 68 patients with confirmed facet joint syndrome. Sensory stimulation was performed at 50 Hz with a 0.5 V cut-off value. Patients were divided into 3 groups according to the twitching of the paravertebral muscle during 2 Hz motor stimulation: 'Complete', when twitching was observed at all needles; 'Partial', when twitching was present at 1 or 2 needles; and 'None', when no twitching was observed. The relationship between the long-term effects of RF-MB and paravertebral muscle twitching was analyzed. Results: The mean effect duration of RF-MB was 4.6, 5.8, and 7.0 months in the None, Partial, and Complete groups, respectively (P = 0.47). Although the mean effect duration of RF-MB did not increase significantly in proportion to the paravertebral muscle twitching, the Complete group had prolonged effect duration (> 6 months) than the None group in subgroup analysis. (P = 0.03). Conclusions: Paravertebral muscle twitching while performing lumbar RF-MB may be a reliable predictor of long-term efficacy when sensory provocation under 0.5 V is achieved. However, further investigation may be necessary for clarifying its clinical significance.ope

Clinical Identification of the Vertebral Level at Which the Lumbar Sympathetic Ganglia Aggregate

BACKGROUND: The location and the number of lumbar sympathetic ganglia (LSG) vary between individuals. The aim of this study was to determine the appropriate level for a lumbar sympathetic ganglion block (LSGB), corresponding to the level at which the LSG principally aggregate. METHODS: Seventy-four consecutive subjects, including 31 women and 31 men, underwent LSGB either on the left (n = 31) or the right side (n = 43). The primary site of needle entry was randomly selected at the L3 or L4 vertebra. A total of less than 1 ml of radio opaque dye with 4% lidocaine was injected, taking caution not to traverse beyond the level of one vertebral body. The procedure was considered responsive when the skin temperature increased by more than 1℃ within 5 minutes. RESULTS: The median responsive level was significantly different between the left (lower third of the L4 body) and right (lower margin of the L3 body) sides (P = 0.021). However, there was no significant difference in the values between men and women. The overall median responsive level was the upper third of the L4 body. The mean responsive level did not correlate with height or BMI. There were no complications on short-term follow-up. CONCLUSIONS: Selection of the primary target in the left lower third of the L4 vertebral body and the right lower margin of the L3 vertebral body may reduce the number of needle insertions and the volume of agents used in conventional or neurolytic LSGB and radiofrequency thermocoagulation.ope

Postoperative Pain and Intravenous Patient-Controlled Analgesia-Related Adverse Effects in Young and Elderly Patients: A Retrospective Analysis of 10,575 Patients

In this retrospective analysis of 10,575 patients who used fentanyl-based intravenous patient-controlled analgesia (IV-PCA) after surgery, we evaluated difference between young and elderly patients on their characteristic of adverse effects.We reviewed the data collected from the patients who were provided IV-PCA for pain control following elective surgery under either general or spinal anesthesia between September 2010 and March 2014. Postoperative pain, incidence of PCA-related adverse effects, and risk factors for the need of rescue analgesics and antiemetics for postoperative 48 hours were analyzed.Pain intensity (numerical rating scale [NRS]) at postoperative 6 to 12 hours (4.68 vs 4.58, P < 0.01) and incidence of nausea or vomiting (23.8% vs 20.6%, P < 0.001) were higher in young patients, while incidence of PCA discontinuation (9.9% vs 11.5%, P < 0.01) and sedation (0.1% vs 0.7%, P < 0.001) was higher in elderly patients. Despite larger fentanyl dose used, a greater proportion of young patients required rescue analgesics (53.8% vs 47.9%, P < 0.001) while addition of ketorolac was effective in reducing postoperative pain. Despite lower incidence of postoperative nausea and vomiting (PONV), a larger proportion of elderly patients required rescue antiemetics (10.1% vs 12.2%, P < 0.001) while addition of ramosetron was effective in reducing PONV.In conclusion, when fentanyl-based IV-PCA is used for postoperative pain control, a larger proportion of young patients may require rescue analgesics while elderly patients may require more rescue antiemetics. The addition of ketorolac or ramosetron to the PCA of young and elderly patients can be effective to prevent rescue analgesics or antiemetics use.ope

Effect of Dexmedetomidine on Heart Rate-Corrected QT and Tpeak-Tend Intervals During Robot-Assisted Laparoscopic Prostatectomy With Steep Trendelenburg Position: A Prospective, Randomized, Double-Blinded, Controlled Study.

Intraperitoneal insufflation of carbon dioxide may affect the sympathetic activity that leads to changes in ventricular repolarization. This in turn can result in changes of heart rate-corrected QT (QTc) interval and Tpeak-Tend (Tp-e) interval. Dexmedetomidine is a highly selective α2-receptor agonist and has potential antiarrhythmic properties. This prospective, randomized, double-blinded, controlled study evaluated the effects of dexmedetomidine administration on QTc and Tp-e intervals during robot-assisted laparoscopic prostatectomy with steep Trendelenburg position.Fifty patients scheduled for robot-assisted laparoscopic prostatectomy randomly received either a continuous infusion of dexmedetomidine at a rate of 0.3 μg/kg/hour, from anesthetic induction until the end of the Trendelenburg position (dexmedetomidine group; n = 25), or the same volume of normal saline (control group; n = 25). Anesthesia was maintained with sevoflurane and remifentanil. The primary and secondary goals were to evaluate the effect of dexmedetomidine on the QTc and Tp-e interval changes. Mean arterial pressure, heart rate, end-tidal CO2, and end-tidal sevoflurane concentrations were assessed as well.Forty-seven patients (94%) completed the study. Dexmedetomidine significantly attenuated QTc interval prolongation and reduced the Tp-e interval, even though the baseline values of the QTc and Tp-e intervals were similar between the 2 groups (PGroup × Time = 0.001 and 0.014, respectively). Twenty-two patients (96%) in the control group and 13 (54%) in the dexmedetomidine group had QTc interval prolongation of >20 ms from the baseline value during surgery (P = 0.001). The maximum QTc interval prolongation from the baseline value during surgery was 46 ± 21 ms in the control group and 24 ± 21 ms in the dexmedetomidine group (mean ± SD, P = 0.001). Mean arterial pressure and heart rate were comparable between the groups.Continuous infusion of dexmedetomidine at a rate of 0.3 μg/kg/hour significantly attenuated the QTc interval prolongation induced by CO2 pneumoperitoneum with steep Trendelenburg position. Furthermore, dexmedetomidine reduced the Tp-e interval. Thus, dexmedetomidine administration may be effective for patients who are susceptible to the development of ventricular arrhythmia during robot-assisted laparoscopic prostatectomy.ope

요추수술환자에서 기도압의 변화로 수술중 출혈량을 예측할 수 있는가?

Dept. of Medicine/석사[한글] 목적: 환자가 복와위 상태에서 수술을 받을 경우 복압의 증가를 일으켜 수술 중 줄혈량을 증가시킬 수 있다. 또한 기계 호흡 동안 복압의 변화는 기도압의 변화에 반영된다. 앙와위에서 복와위로 체위 변경시 환자의 기도압 변화와 수술 중 출혈량의 관계를 조사하였다. 방법: 요추 수술을 받는 환자들은 Wilson frame을 이용하여 복와위를 취하였다. 마취 유도 후 5분과 복와위를 취한 후 15분 뒤에 최대 기도압, 고평부압, 평균혈압, 맥박수를 측정하고 수술이 끝난 후 수술 중 출혈량을 측정하였다. 결과: 다른 지표들에 비해 앙아위에서 복와위로 자세 변경 시 최대 기도압의 증가가 수술 중 출혈량의 증가를 가장 잘 반영하며 가장 높은 R2 값과 유의성을 보였다. 최대기도압이 1 Kpa 증가하면 수술 중 출혈량이 한 척추 분절 당 63.8 ml 증가하는 것으로 예측할 수 있다. 결론: 앙아위에서 복아위로 자세 변경시 최대기도압의 증가로 수술 중 출혈량이 증가를 예측할 수 있다.prohibitio

Digital halftoning with value adaptive error diffusion

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