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Background: Neuropathic pain (NP) is considered a clinically incurable condition despite various treatment options due to its diverse causes and complicated disease mechanisms. Since the early 2000s, multipotent human mesenchymal stem cells (hMSCs) have been used in the treatment of NP in animal models. However, the effects of hMSC injections have not been studied in chronic post-ischemia pain (CPIP) mice models. Here, we investigated whether intrathecal (IT) and intrapaw (IP) injections of hMSCs can reduce mechanical allodynia in CPIP model mice. Methods: Seventeen CPIP C57/BL6 mice were selected and randomized into four groups: IT sham (n = 4), IT stem (n = 5), IP sham (n = 4), and IP stem (n = 4). Mice in the IT sham and IT stem groups received an injection of 5 μL saline and 2 × 104 hMSCs, respectively, while mice in the IP sham and IP stem groups received an injection of 5 μL saline and 2 × 105 hMSCs, respectively. Mechanical allodynia was assessed using von Frey filaments from pre-injection to 30 days post-injection. Glial fibrillary acidic protein (GFAP) expression in the spinal cord and dorsal root ganglia were also evaluated. Results: IT and IP injections of hMSCs improved mechanical allodynia. GFAP expression was decreased on day 25 post-injection compared with the sham group. Injections of hMSCs improved allodynia and GFAP expression was decreased compared with the sham group. Conclusions: These results suggested that hMSCs may be also another treatment modality in NP model by ischemia-reperfusion.

Background: Thyroid surgery is usually performed under general anesthesia, but thyroid surgery under monitored anesthesia care (MAC) has become re-introduced. We report our experiences of 40 cases of thyroid surgery under MAC. Methods: Forty patients were enrolled in this study. Bilateral superficial cervical plexus block (BSCPB) was performed by using 1% mepivacaine with 1:200,000 epinephrine. After BSCPB, patients were sedated with propofol and fentanyl. Postoperative pain, sore throat, hoarseness, and postoperative nausea and vomiting (PONV) were assessed. Results: Mean postoperative pain VAS were 1.3, 1.2, 1.0, 0.8 and postoperative sore throat VAS 1.4, 1.4, 1.1, 0.9 at PACU (post-anesthesia care unit) and postoperative 3, 6, 12 h, respectively. The incidence of hoarseness was 25, 5, 2.5%, and 0% and PONV were 0, 5, 10%, and 7.5% at PACU and postoperative 3, 6, 12 h, respectively. Conclusions: Thyroid surgery under MAC may be a suitable alternative to general anesthesia. (Korean J Anesthesiol 2009; 56: 284~9)

Background: Magnesium presents analgesic effects by blocking the non-competitive N-methyl-D-aspartate receptor in the spinal cord. The purpose of this study was to evaluate the effects of epidural magnesium on cumulative dose of ropivacaine in patients with patient-controlled epidural analgesia (PCEA) after a thoracotomy. Methods: In a randomized, prospective, double-blind trial, we enrolled 40 patients undergoing PCEA after a thoracotomy. Control group (n = 20) received an initial dose of 0.375% ropivacaine 0.1 ml/kg, and following demand doses of 0.2% ropivacaine 2 ml with 15 min lockout interval on the patient demand. Magnesium group (n = 20) additionally received MgSO4 100 mg in the initial dose and 4 mg in the demand doses. Cumulative dose of ropivacaine, the resting and coughing visual analog scale (VAS) score were measured at 3, 6, 12, 24, and 48 hours after surgery. Results: Magnesium group showed lower cumulative dose of ropivacaine than control group at 12, 24, and 48 hours after the surgery (P ＜ 0.05), but not at 3 and 6 hours (P ＜ 0.05). The VAS score was not different between 2 groups (P ＜ 0.05). Conclusions: Epidural magnesium may be useful as an adjuvant to ropivacaine after a thoracotomy. However, because magnesium showed no beneficial effect at the early period after the surgery, more investigation about proper initial dose is required. (Korean J Anesthesiol 2009; 57: 466∼71)

Case report.To report an unusual case of vastus lateralis muscle rupture not accompanied by any history of major trauma or the presence of a risk factor in a patient with spinal stenosis. Isolated vastus lateralis muscle rupture without an obvious cause is very rare. Localized pain and claudication are the most common symptoms and can be misdiagnosed as lumbar radiculopathy.A 70-year-old patient presented with right lower extremity and back pain, diagnosed as spinal stenosis. He was initially treated with caudal epidural block and transforaminal epidural block, which resulted in nearly complete relief of his symptoms. However, he subsequently experienced a pain that was no longer responsive to treatment. The ultrasonographic exam revealed a partial tear of the right vastus lateralis muscle.Injection of local anesthetics relieved the patient's symptoms. At 1-month follow-up, he remained pain-free.In patients with lower back and leg pain, physicians should consider non-spinal conditions that can cause signs and symptoms mimicking lumbar radiculopathy.

This study was performed to examine whether applying triamcinolone acetonide paste as a lubricant to endotracheal tubes (ETTs) reduces the incidence and severity of postoperative sore throat (POST) more effectively than applying chlorhexidine gluconate jelly.This was a randomized controlled clinical trial. Patients enrolled in the study were ages 20 to 70 yr, American Society of Anesthesiologists' physical status I and II, and scheduled for elective laparoscopic cholecystectomy. The patients were divided randomly into two groups, the chlorhexidine group and the triamcinolone group. Prior to endotracheal intubation, ETTs in the chlorhexidine group were lubricated with 0.1% chlorhexidine gluconate jelly, whereas the ETTs in the triamcinolone group were lubricated with 0.1% triamcinolone acetonide paste 0.5 mg. During the 24 hr after the operation, we recorded the incidence and severity of POST and the incidence of cough, hoarseness, dysphagia, nausea, and dry throat.Of the 150 patients initially enrolled, 143 patients were included in the study. The incidence of POST was significantly lower in the triamcinolone group compared with the chlorhexidine group (difference = 52.4%; 95% confidence interval, 36.8% to 64.2%; P0.001). The severity score for the triamcinolone group was significantly lower than that for the chlorhexidine group. The frequencies of coughing, hoarseness, dysphagia, nausea, and dry throat were similar in the two groups for the first 24 hr after surgery.Triamcinolone acetonide paste applied along the length of the ETT resulted in clinically important and statistically significant decreases in the incidence and severity of POST compared with the application of chlorhexidine jelly. (ClinicalTrials.gov number, NCT00908817).

Background The use of lipid soluble opioids such as fentanyl, alfentanil and sufentanil are recently on the increase for patient-controlled epidural analgesia (PCEA). In this study, the effects and adequate dose of sufentanil in arthroplasty were investigated. Methods Eighty patients scheduled for arthroplasty were enrolled for the study. Seventy-one patients (ASA physical status I-III) were randomly allocated into four groups. All groups received 0.1% ropivacaine through PCEA and each group received either fentanyl (group F: fentanyl 4 µg/ml) or sufentanil (group S1: sufentanil 0.5 µg/ml, group S2: sufentanil 0.75 µg/ml, and group S3: sufentanil 1.0 µg/ml). Postoperative pain scores were evaluated using VAS (visual analog scale, 0-10) and side effects such as hypotension, nausea/vomiting, pruritus and the degree of satisfaction were evaluated at 1, 6, 12, 24, 48 hours after surgery. Results Postoperative pain score (VAS) decreased gradually and the highest VAS score was recorded at 1 hour postoperative for all four groups. There were no differences in the degree of satisfaction and postoperative pain score between all groups. The incidence of pruritus was significantly lower in group S1 than in groups S2 and S3. Conclusions The incidence of side effects were significantly lower in group S1 (0.1% ropivacaine plus sufentanil 0.5 µg/ml). Therefore, 0.5 µg/ml of sufentanil through PCEA is the recommended dose for postoperative pain control in arthroplasty.

Background This study was performed to compare the effectiveness of prophylactic dexamethasone and postintubation dexamethasone in reducing the incidence and severity of postoperative sore throat (POST). Methods This was a prospective, randomized, double-blind clinical trial. The study population consisted of 70 patients between 20 and 60 years old who were classified as American Society of Anesthesiologists I-II and were scheduled for elective laparoscopic cholecystectomy. The patients were divided randomly into two groups. Patients in the prophylactic and postintubation groups received intravenous injection of 10 mg of dexamethasone 30 min before or after tracheal intubation, respectively. The patients were interviewed 1, 6, and 24 h after the operation. The incidence and severity of POST were recorded. Results The severity scores of POST at 1 and 6 h after the operation were significantly lower in the prophylactic group than in the postintubation group. There were no significant differences in the incidence of POST during the 24 h after the operation between the two groups (22/32 in the prophylactic group vs. 27/34 in the postintubation group, P = 0.403). Conclusions Intravenous injection of 10 mg of dexamethasone was more effective in reducing the severity of POST when administered before tracheal intubation compared with after tracheal intubation.

BACKGROUND: We evaluated the epidural administration of tezampanel, a non-N-methyl-D-aspartate receptor antagonist, in a rat model for postoperative pain. We sought to determine if this drug affects nociception when administered epidurally by testing its effects on responses to heat in normal rats. The effects of epidural tezampanel on pain-related behaviors in rats that underwent plantar incision were also studied. METHODS: Rats were anesthetized and epidural catheters were placed. One day after epidural catheterization, the baseline heat withdrawal latency was measured. Epidural tezampanel or morphine was tested for analgesia by examining their effects against heat withdrawal latency. Motor function was also tested. Comparisons to subcutaneous drug administration were made. Other rats underwent plantar incision after epidural catheterization to assess pain behavior caused by incision. The effects of epidural tezampanel on the cumulative pain scoring, based on guarding, the withdrawal threshold to von Frey filament application, and the withdrawal latency to heat, were measured. The effects of epidural tezampanel on arterial blood pressure and heart rate were also tested. RESULTS: Both epidural morphine and epidural tezampanel increased withdrawal latency to heat. Only subcutaneous morphine affected heat withdrawal latency. After plantar incision, epidural tezampanel decreased the median guarding pain score, increased the heat withdrawal latency and increased the mechanical withdrawal threshold indicating analgesic effects. Arterial blood pressure and heart rate did not change after epidural drug administration. CONCLUSION: These experiments demonstrate that epidural administration of tezampanel produces analgesia to heat, motor side effects in some rats, and reduces pain behaviors caused by incision. No systemic analgesia was apparent using the largest dose.

Background: The word “geop” is a unique Korean term commonly used to describe fright, fear and anxiety, and similar concepts. The purpose of this pilot study is to examine the correlation between the Numeric Rating Scale (NRS) score of geop and three different questionnaires on pain perception. Methods: Patients aged 20 to 70 years who visited our outpatient pain clinics were evaluated. They were requested to rate the NRS score (range: 0−100) if they felt geop. Next, they completed questionnaires on pain perception, in this case the Korean version of the Pain Sensitivity Questionnaire (PSQ), the Pain Catastrophizing Scale (PCS), and the Pain Anxiety Symptoms Scale (PASS). The correlations among each variable were evaluated by statistical analyses. Results: There was no statistically significant correlation between the NRS score of geop and the PSQ score (r = 0.075, P = 0.5605). The NRS score of geop showed a significant correlation with the PCS total score (r = 0.346, P = 0.0063). Among the sub-scales, Rumination (r = 0.338, P = 0.0077) and Magnification (r = 0.343, P = 0.0069) were correlated with the NRS score of geop. In addition, the NRS score of geop showed a significant correlation with the PASS total score (r = 0.475, P = 0.0001). The cognitive (r = 0.473, P = 0.0002) and fear factors (r = 0.349, P = 0.0063) also showed significant correlations with the NRS score of geop. Conclusions: This study marks the first attempt to introduce the concept of “geop.” The NRS score of geop showed a moderate positive correlation with the total PCS and PASS score. However, further investigations are required before the “geop” concept can be used practically in clinical fields. (Korean J Pain 2015; 28: 32-38)

Background: Ketamine, an N-methyl-D-aspartate receptor antagonist, might play a role in postoperative analgesia, but its effect on postoperative pain after caesarean section varies with study design. We investigated whether the preemptive administration of low-dose intravenous ketamine decreases postoperative opioid requirement and postoperative pain in parturients receiving intravenous fentanyl with patient-controlled analgesia (PCA) following caesarean section. Methods: Spinal anesthesia was performed in 40 parturients scheduled for elective caesarean section. Patients in the ketamine group received a 0.5 mg/kg ketamine bolus intravenously followed by 0.25 mg/kg/h continuous infusion during the operation. The control group received the same volume of normal saline. Immediately after surgery, the patients were connected to a PCA device set to deliver 25-μg fentanyl as an intravenous bolus with a 15-min lockout interval and no continuous dose. Postoperative pain was assessed using the cumulative dose of fentanyl and visual analog scale (VAS) scores at 2, 6, 24, and 48 h postoperatively. Results: Significantly less fentanyl was used in the ketamine group 2 h after surgery (P = 0.033), but the difference was not significant at 6, 12, and 24 h postoperatively. No significant differences were observed between the VAS scores of the two groups at 2, 6, 12, and 24 h postoperatively. Conclusions: Intraoperative low-dose ketamine did not have a preemptive analgesic effect and was not effective as an adjuvant to decrease opioid requirement or postoperative pain score in parturients receiving intravenous PCA with fentanyl after caesarean section. (Korean J Pain 2013; 26: 270-276)

BACKGROUND: Chronic postoperative pain (CPOP) is defined as pain of at least 2 months duration after a surgical procedure. Until recently, it has been a neglected topic, because it can occur after a wide spectrum of operations; however, little is known regarding its underlying mechanism, prevalence, risk factors, and treatments. We investigated characteristics of CPOP after various operations via a questionnaire. METHODS: Patients were contacted at > 2 months after surgery, irrespective of sex, type of operation or anesthesia method, and a follow-up pain questionnaire was administered by phone. RESULTS: One hundred forty-five of 400 patients (36.3%) described CPOP. The prevalence of CPOP was significantly lower in laparoscopic surgery (29/159, 18.2%) than open surgery (116/241, 48.1%). The prevalence of CPOP was higher with the use of PCA (patient controlled analgesia), (45.3%) than without PCA (24.6%). There were no significant differences regarding sex, anesthetic method, or duration of operation. CONCLUSIONS: Our results indicate that the prevalence of CPOP may be related to use of an endoscope and PCA. However, it is difficult to completely explain the correlation, because this is a complex area of research. More research is needed to improve the quality of pain relief.

Interscalene brachial plexus block (interscalene block) complications usually depend on the dose administered. The objective of this study was to determine whether ultrasound-guided interscalene block with a 5-mL dose of 0.75% ropivacaine would have sufficient analgesic efficacy after shoulder arthroscopic surgery when compared with a 10-mL dose. Patients undergoing arthroscopic rotator cuff repair surgery (n = 60) were assigned randomly to one of two groups receiving 5 mL (Group 5) or 10 mL (Group 10) of 0.75% ropivacaine. Ultrasound-guided interscalene block was performed using the in-plane technique, and general anesthesia was administered. Time to first analgesic request was recorded, and the following issues were assessed in the postanesthesia care unit at six, 12, 24, and 48 hr postoperatively: postoperative pain as determined by a visual analogue scale (VAS), patient satisfaction, hemidiaphragmatic paralysis, other block-related complications, and postoperative nausea and vomiting (PONV). There was no significant difference between groups in time to first analgesic requirement (median [interquartile range] for Group 5: 16 [12-48] hr, Group 10: 18 [12-48] hr; P = 0.907). The postoperative pain VAS score was similar in both groups. The incidence of hemidiaphragmatic paralysis on postoperative chest x-ray was 33% in Group 5 and 60% in Group 10 (P = 0.035). However, the incidences of other block-related complications, PONV, and patient satisfaction were not significantly different between groups. Interscalene block performed under ultrasound guidance with 0.75% ropivacaine 5 mL showed analgesic efficacy similar to that with 0.75% ropivacaine 10 mL, but with a lower incidence of hemidiaphragmatic paralysis.

Pulsed radiofrequency (PRF) has been used to manage a wide spectrum of chronic pain modalities because it produces fewer histopathological changes than conventional RF and takes advantage of a significant reduction in complications or side effects [1]. Many reports have indicated that PRF improves chronic pain when applied to various neural tissues, including the dorsal root ganglion [2], cranial nerves [3], medial branches of spinal nerves [4], and other peripheral nerves [5]. Unlike neural tissues, few reports have investigated the effect of applying PRF to non-neural tissues. In the latest issue of The Korean Journal of Pain, Fukui et al. [6] reported a clinical study that compared the effects of intradiscal PRF and electrothermal therapy in 31 patients with lumbar discogenic pain. In this trial, intradiscal PRF was as effective as electrothermal therapy. At up to the 6 month follow-up, the mean numeric rating scale and Roland-Morris Disability Questionnaire score improved significantly after intradiscal PRF was applied for 15 min under conditions 5 × 50 ms/s and 60 V. Three other pilot studies, which included no control group, showed the effectiveness of intradiscal PRF for discogenic pain [7-9]. However, we are unaware of the long-term effectiveness and safety of intradiscal PRF. Further randomized controlled studies with long-term follow-up durations are crucial to verify the efficacy and safety of intradiscal PRF. The editor found a retrospective study and two case reports by PubMed search regarding the effect of intra-articular application of PRF. Karaman et al. [10] reviewed 31 patients with osteoarthritis of the knee who received intra-articular PRF retrospectively. After applying PRF at 42℃ and 2 Hz for 15 minutes, the mean initial visual analog scale scores of patients (6.1 ± 0.9) decreased to 3.9 ± 1.9 cm and 4.1 ± 1.9 cm at the 1- and 6-month follow-ups respectively. Sluijter et al. [11] reported six cases of patients with intractable arthrogenic pain who were treated with intra-articular PRF. In this case series, PRF was applied by placing an electrode into joint spaces, including the cervical facet joint, the knee joint, the sacroiliac joint, the radiocarpal joint, the shoulder joint, and the atlanto-axial joint. All participants experienced a significant reduction in pain or a pain-free state. Ozyuvaci et al. [12] reported somewhat negative results for a patient with ruptured shoulder ligaments and two patients with degeneration and osteoathrosis of the glenohumeral joint. Applying PRF to the glenohumeral joint provided some pain relief to patients at 3 weeks but not at 8 weeks. They concluded that PRF can be used as an alternative and palliative treatment with both analgesic and physiotherapeutic procedures, but that it may not be sufficient therapy for patients with chronic shoulder pain. Some case reports have described the effect of applying PRF to soft tissues, including the pain-relieving point, the trigger point, and other tissues. Lee et al. [13] reported a patient who experienced pain relief lasting more than 5 months after PRF treatment to the pain-relieving point in the posterior neck. In a case series of PRF treatment of myofascial trigger points and scar neuromas, nine patients were treated over an 18-month period [14]. Eight patients experienced 75-100% reduction in their pain following PRF treatment at 4 weeks following treatment. Six patients experienced 6 months to longer than 1 year of pain relief. Park et al. [15] observed that PRF treatment to the trapezius muscle trigger point produces long lasting myofascial pain relief. Misra et al. [16] treated chronic testicular pain with PRF stimulation of the spermatic cord in a preliminary report. Of the nine patients evaluated, four had complete pain resolution, whereas one had partial pain relief. They concluded that PRF applied to the spermatic cord appeared to be a safe, minimally invasive outpatient procedure that should be investigated further in placebo-controlled trials. Although some case reports, case series, and preliminary studies of PRF have been conducted on non-neural tissues, we do not have confirmation of the safety and the effectiveness on these tissues and do not know the exact mechanism of action. More prospective randomized controlled studies on applying PRF to non-neural tissues are mandatory to guarantee the safety and effectiveness of this therapy on such tissues. Experimental studies on histopathological and biochemical changes produced by PRF are necessary to understand the precise mode of action of PRF.

Background: Clinically rocuronium, a muscle relaxant, has no significant inhibitory effect on the autonomic nervous system in the healthy population. However, there has been no study done on rocuronium in diabetic patients. Therefore, we used heart rate variability (HRV) as a biomarker to investigate cardiac autonomic function after rocuronium administration to diabetic patients. Methods: In 21 diabetic adult patients, heart rate (HR), mean arterial blood pressure (BP), low frequency (LF, 0.04−0.15 Hz) power, high frequency (HF, 0.15−0.4 Hz) power, LF/HF ratio, SD1 and SD2 in the Poincare plot before induction of anesthesia, and immediately before and after rocuronium administration were calculated and compared. Results: HR, mean BP, LF, LF/HF ratio and SD2 after rocuronium administration did not differ significantly from the measurements taken before rocuronium administration. HF and SD1 decreased significantly after rocuronium administration (P = 0.022, P = 0.019 respectively). Covariates such as age, gender, weight, duration of diabetes mellitus and hypertension did not alter the effect of rocuronium on the autonomic nervous system. Conclusions: Rocuronium produced a significant decrease in parasympathetic activity. Therefore, further study will be needed to determine whether vagal reduction caused by rocuronium could have potential to deteriorate hemodynamics in diabetic patients. (Korean J Anesthesiol 2009; 57: 165∼9)

Background: We sought to assess whether increasing a single dose of 1.5% lidocaine during thoracic epidural anesthesia (TEA) could suppress hemodynamic responses after laryngoscopy and tracheal intubation. Methods: A total of 81 patients (ASA physical status I and II, aged 45−75) who scheduled for major abdominal surgery were enrolled. Patients were randomly assigned to three groups, for epidural injection of different amounts of 1.5% lidocaine: 0.1 ml/kg (L0.1, n = 27), 0.2 ml/kg (L0.2, n = 27), and 0.3 ml/kg (L0.3, n = 27). After 15 min, general anesthesia was induced with intravenous thiopental sodium (5 mg/kg) and rocuronium (0.9 mg/kg), followed by tracheal intubation. Changes in blood pressure and heart rate were recorded for 3 min after intubation. Maximum percentage increases in systolic blood pressure (SBP) during the 3 min after tracheal intubation from baseline and the induction value were compared. Results: The maximum increases in SBP from baseline values were significantly higher in L0.1 than in L0.2 and L0.3 (22.6%; 95% CI, 12.2−33.0%; -0.5%; 95% CI, -11.1−10.0%; and -6.9%; 95% CI, -13.9−0.0%, respectively), whereas the maximum increases from induction values did not differ significantly. Conclusions: Preoperative TEA using a single dose of 1.5% lidocaine at 0.2 ml/kg attenuated hemodynamic responses during tracheal intubation but did not completely suppress blood pressure reactions to laryngoscopy and tracheal intubation. (Korean J Anesthesiol 2008; 55: 429∼35)

Background: Several methods have been attempted to enhance the success rate of tracheal intubation using a lightwand. Some studies have reported that changing the shape of a lightwand and the position of the head during intubation could influence the intubation time or success rate. However, there are no reports concerning the head position of a patient on influencing the success rate during tracheal intubation using a lightwand. Methods: We enrolled 109 ASA physical status 1 and 2 patients scheduled for elective surgery under general anesthesia. Patients were randomly allocated to the sniffing group (n=52) or neutral group (n=57), depending on the head position. A lightwand (Surch-LiteTM, Bovie/Aaron Medical, St. Petersburg, USA) was bent at 9.5 cm from the distal tip with a 0 cm extrusion for both groups of patients (J shape). The head was elevated by approximately 8 cm in the sniffing group of patients and by approximately 2 cm in the neutral group of patients, with the face straight up maintained by placement of a pillow. Results: The overall success rate at the first attempt was 98.1%. There were no differences in the mean intubation time between the two groups (sniffing group; 8.0±4.3 sec and neutral group; 9.3±4.1 sec). The mean intubation time tended to be longer in patients with modified Mallampati classification 3 than in patients with modified Mallampati classification 1 and 2. Conclusions: This study has demonstrated that the use of a J shaped lightwand did not affect the intubation time, regardless of the head position. The intubation time appears to be related to the airway condition when using a lightwand for tracheal intubation.

We report two cases of Jehovah`s Witness patients who had massive bleeding after surgery. The first case was a 37-year-old woman who underwent an emergency cesarean section; the other was a 48-year-old man with chronic anemia who underwent removal of a large mass. After the operation, their Hb levels were nearly 3.1 g/dl. They were treated with blood conserving methods, divided into 3 periods (pre, post and operative). Both patients completely recovered uneventfully and were discharged on the 19th and 21st postoperative day. (Korean J Anesthesiol 2008;55:621~4)

Background: The oncogene, c-fos, is a useful marker of nociceptive neurons activated by various types of pain. However, the relationship between c-fos and acute pain induced by surgical incision has not been studied. The purpose of this study was to describe the expression of spinal c-fos in a rat model of postoperative pain. Methods: Sprague-Dawley rats were used to enumerate spinal fos-like immunoreactive (fos-LI)-positive neurons after making sham, skin, or skin-muscle incisions on the plantar surface of the rat hindpaw. The spinal cords were divided into the following 4 segments for immunohistochemical detection of fos-LI at 3 time points after the incision (4 hours, POD1, and POD3): thoracic, upper lumbar, lower lumbar, and sacral. For analysis of the laminar distribution of fos-LI, the dorsal horn was divided into three regions (I−II, III−IV, and V−VI). Results: The number of fos-LI was increased in the ipsilateral spinal dorsal horn in the lower lumbar segment 4 hours post-incision and was significantly greater in rats with skin-muscle incisions than in rats with skin-alone incisions. In the skin-muscle group, laminae I− II and V−VI had a greater number of fos-LI neurons than laminae III−IV. The increase in number of spinal fos-LI neurons normalized by POD1 and POD3. Conclusions: c-fos expression is confined to neurons of the spinal dorsal horn known to be activated by nociceptive stimulation. The larger the injury elicited, the greater the expression of c-fos, suggesting that the expression of c-fos can serve as a useful marker of activated nociceptive neurons caused by acute pain following surgical incision. Further study is required to elucidate why the degree of tissue injury affects the laminar distribution of c-fos expression. (Korean J Anesthesiol 2008; 54: 328∼34)

End-tidal carbon dioxide tension (PETCO2) is widely used to estimate arterial carbon dioxide tension (PaCO2) under various clinical conditions. This study was conducted to determine if PETCO2 during one lung ventilation (OLV) is as useful as PETCO2 during two lung ventilation (TLV) for predicting PaCO2. Methods: Forty patients undergoing thoracic surgery were enrolled in this study. During OLV (n = 20) and TLV (n = 20), PaCO2 and PETCO2 were measured. The arterial-end tidal carbon dioxide difference (Pa-ETCO2) was then calculated and a correlation between PaCO2 and PETCO2 was evaluated during OLV and TLV. Results: Pa-ETCO2 was significantly higher during OLV (8.9 ± 5.1 mmHg) than during TLV (6.1 ± 3.9 mmHg). In addition, the correlation between PETCO2 and PaCO2 was less significant during OLV (R2 = 0.43) than during TLV (R2 = 0.59). Conclusions: PETCO2 during OLV was not as accurate as PETCO2 during TLV for predicting PaCO2, which indicates that greater attention should be given to the maintenance of normocarbia during OLV than during TLV.

Background: There are many reports showing that a thoracic paravertebral block (TPB) can be used for post-thoracotomy pain control. However, the proper concentration of local anesthetics for TPB has not been established. The aim of this study was to define the proper concentration of bupivacaine for TPB after a thoracotomy. Methods: Sixty patients were allocated randomly into one of the following three groups: thoracic paravertebral 0.5%, 0.25%, or 0.125% bupivacaine at a rate of 0.1 ml/kg/h (kg: ideal body weight). The resting and coughing visual analogue scale (VAS) score, cumulative dose of fentanyl, and the 5 point satisfaction scale were checked. Results: 0.5% and 0.25% bupivacaine showed lower VAS score and cumulative dose of fentanyl than 0.125%. There was no difference in the satisfaction scale between the 3 groups. There was no difference between the 0.5% and 0.25% bupivacaine in all parameters measured. Conclusions: 0.25% bupivacaine used for TPB is more effective when used for pain control after a thoracotomy than 0.5% and 0.125% bupivacaine.

Background: We designed this study to find the appropriate dose of fentanyl for the prevention of emergence agitation in pediatric tonsillectomy patients under sevoflurane anesthesia. Methods: Sixty pediatric patients receiving sevoflurane anesthesia for tonsillectomy was assigned to 3 groups. Fentanyl 0.5/kg(group 1), 1.0/kg (group 2), or 1.5/kg (group 3) was administered intravenously 10 min before the end of surgery. Agitation score was checked at the postanesthesia care unit. Results: The results showed a lower incidence of severe agitation in groups 2 and 3 than in group 1. There was no difference between groups 2 and 3. Conclusions: For preventing emergence agitation after sevoflurane anesthesia, we recommend using fentanyl in a dose of more than 1.0/kg.

Background: It is well known that sevoflurane anesthesia is associated with emergence agitation (EA) in children, and that fentanyl may reduce its incidence. However, in case of midazolam, there have been conflicting reports. Therefore, we measured the effect of midazolam on EA after sevoflurane anesthesia and compared it with that of fentanyl. Methods: Sixty pediatric patients receiving sevoflurane anesthesia for tonsillectomy was assigned to 3 groups. Saline 0.1 ml/kg (group P), midazolam 0.1 mg/kg (group M), or fentanyl 1/kg (group F) was administered intravenously 10 minutes before the end of surgery. The incidences of over-sedation (OS) and EA were checked three times at the postanesthesia care unit. Results: Group M had a tendency to show a high incidence of OS, but its incidence of EA was not different from the other groups. In group F, OS and EA were less frequent than in groups P and M. Conclusions: After sevoflurane anesthesia for tonsillectomy, fentanyl effectively prevented EA, but midazolam elicited OS and was ineffective at preventing EA.

A 62-year-old woman with two vessel coronary artery disease was scheduled for an off-pump coronary artery bypass graft. Under general anesthesia, a 7.5 Fr pulmonary artery (PA) catheter (AH-05050-H, Arrow, USA) was inserted via an 8.5 Fr introducer in the right internal jugular vein. After several attempts, it was successfully guided into the PA, and the systolic/diastolic/mean pressure was 28/10/16 mmHg at 45 cm insertion. Since the catheter migrated into an overwedged position during the operation, the catheter was withdrawn several centimeter. After a while, a sudden change of PA pressure waveform to plateau was noticed, and then PA pressure fell into 0/0/0 mmHg. The PA catheter tip was seen protruding through the normal-appearing anterior wall of the right ventricle. The catheter was withdrawn to a right atrial position, and the perforation was closed. The operation was finished uneventfully and the patient remained stable for the next 14 days and was discharged home. In this case, withdrawal of the PA catheter probably placed its tip in the origin of the PA, from which it then slipped into and perforated the right ventricle. After withdrawal of a PA catheter to avoid an overwedged position, the balloon of the catheter should be re-advanced into a proper position or be withdrawn to a right atrial position.

Background: The primary objective of this study was to determine the effect of fentanyl, esmolol, and lidocaine on arterial blood pressure (BP) and heart rate (HR) following endotracheal intubation (ETI) and during an operation in patients with chronic renal failure (CRF) undergoing an arteriovenous fistula (AVF). Methods: Sixty CRF patients who underwent creation of an AVF were analyzed for this study. Before ETI, the patients were randomly placed in a control group (CONT, n = 15), fentanyl group (FENT, 2/kg, n = 15), esmolol group (ESM, 1 mg/kg, n = 15), or lidocaine group (LID, 1 mg/kg, n = 15) and then each drug was administered before ETI. HR and BP were measured before intubation (baseline), after intubation, immediately after surgical incision (A-Inc), 15 min (A-Inc15) and 30 min (A-Inc30) after surgical incision. Mean arterial pressure was controlled between 20% of the pre-intubation value with the control of inspired fraction of isoflurane, and with ephedrine or clonidine. Results: The HR was not different among groups. The elevation of BP following ETI in FENT was less than in CONT. BP was lower in FENT at A-Inc, A-Inc15, and A-Inc30 than in CONT, ESM, or LID. The administered dose of clonidine was not different among groups, but that of ephedrine was larger in FENT than in CONT. Conclusions: In CRF patients undergoing an AVF, esmolol 1 mg/kg and lidocaine 1 mg/kg could not prevent the elevation of BP and HR following ETI. The elevation BP after ETI was blunted by fentanyl 2/kg, but it decreased BP during the operation and increased the requirement of ephedrine. It is concluded that further studies must be made about the adminstration of a shorter acting opioid and of a larger dose of esmolol and lidocaine for preventing elevation of BR and HR in CRF patients undergoing an AVF.