[Evaluation of postoperative pain intensity related to post-thoracotomy pain syndrome occurring after video-assisted thoracic surgery lobectomy for lung cancer].

BACKGROUND: We conducted a retrospective study to evaluate the relationship between post-thoracotomy pain syndrome (PTPS) and early postoperative analgesia with multimodal analgesia administered via a combination of patient-controlled epidural analgesia (PCEA) and nonsteroidal anti-inflammatory drugs (NSAIDs) in patients who had undergone video-assisted lobectomy for lung cancer. METHODS: A total of 73 adult patients were divided into 2 groups: group A included 12 patients (16.4%) with PTPS, and group B included 61 patients without PTPS. All patients received postoperative multimodal analgesia via a combination of NSAIDs and PCEA with a mixture of 2 microg x ml(-1) fentanyl and 1.5 mg x ml(-1) ropivacaine. For statistical analyses, unpaired t-test, Mann-Whitney test and chi square test were used and considered P significant if lower than 0.05. RESULTS: Pain intensity was measured on a 100-mm non-graduated visual analogue scale (VAS), and it was significantly greater in group A (8 mm) than that in group B (2 mm). There was no significant difference between groups in pain intensity during movement, with a VAS score of 33 mm in group A and 35 mm in group B. The number of PCEA bolus injections given to patients was significantly higher in group A (3 times) than in group B (2 times). The duration of PCEA was also significantly longer in group A (4 days) than in group B (3 days). There was no significant difference in the rate of NSAIDs usage between the 2 groups CONCLUSIONS: This study demonstrated a significant difference in early postoperative pain intensity between patients with PTPS and those without. We conclude that there is a possibility of intervention in the early postoperative period in patients who underwent thoracic surgery.

Long-term administration of fluvoxamine attenuates neuropathic pain and involvement of spinal serotonin receptors in diabetic model rats.

Diabetic neuropathic pain management is difficult even with non-steroidal anti-inflammatory drugs and narcotic analgesics such as morphine. Fluvoxamine, a class of selective serotonin reuptake inhibitors (SSRIs), is widely used to treat depression. Its analgesic effects are also documented for diabetic neuropathic pain, but they are limited because it is administered as a single-dose. In this study, we examined the time course of the antiallodynic effect of fluvoxamine in a rat model of diabetic neuropathic pain, which was induced by a single intraperitoneal administration of streptozotocin (75 mg/kg). In addition, the involvement of spinal serotonin (5-HT) receptors in long-term fluvoxamine treatment was studied by intrathecal administration of 5-HT receptor antagonists. In this study the development of mechanical hyperalgesia was assessed by measuring the hind paw withdrawal threshold using von Frey filaments. The results demonstrated that daily oral administration of fluvoxamine (10, 30, and 100 mg/kg) to diabetic rats from 3 to 8 weeks after streptozotocin administration resulted in a dose-dependent antiallodynic effect. The antiallodynic effect was sustained from 2 to 5 weeks after fluvoxamine administration. The antiallodynic effect of fluvoxamine in the diabetic rats was attenuated by WAY-100635 (a 5-HT(1A) receptor antagonist) intrathecally administered 1 week after the onset of daily administration of fluvoxamine, whereas no significant attenuation was seen when the antagonist was administered 3 and 5 weeks after fluvoxamine administration. The antiallodynic effect of fluvoxamine was also attenuated by ketanserin (a 5-HT(2A/2C) receptor antagonist) and ondansetron (a 5-HT3 receptor antagonist) intrathecally administered 1 and 3 weeks after the onset of daily fluvoxamine administration. However, no significant attenuation was observed when the antagonist was administered 5 weeks after fluvoxamine administration. This study demonstrated that daily oral administration of fluvoxamine can afford a sustained antiallodynic effect against streptozotocin-induced neuropathic pain. Furthermore, there appears to be a time-dependent relevance of different types of 5-HT receptors (5-HT(1A), 5-HT(2A/2C), and 5-HT3) to streptozotocin-induced diabetic neuropathic pain when treated with daily fluvoxamine.

[Postoperative pain management by intravenous patient-controlled analgesia in patients undergoing upper abdominal gastrointestinal surgery].

BACKGROUND: We conducted a retrospective study to evaluate the effectiveness of intravenous patient-controlled analgesia (IVPCA) in the early postoperative period after upper abdominal gastrointestinal surgery. We also evaluated the postoperative effects of intraoperative analgesic dosage in patients after this surgery. METHODS: A total of 59 adult patients classified as ASA 1-3 were allocated to one of two groups: Group A, 23 patients who requested IVPCA more than 50 times, and Group B, 36 patients with fewer than 50 requests. IVPCA was induced using morphine 1 mg x ml(-1) without a base dose. The bolus dose was 1 ml and the lock-out time was 5 min. RESULTS: There was no significant difference between the two groups in the total intraoperative remifentanil dosage/body weight/surgical duration, predicted effect-site concentration of fentanyl during extubation, and utilization of flurbiprofen. The doses of morphine were significantly higher, and the visual analogue scale scores for pain at rest and during movement tended to be lower in group A than in group B. CONCLUSIONS: The results of this study suggest that the effects of intraoperative analgesics may not be significant. Patients who had received the above mentioned anesthetic regimen intraoperatively also required full postoperative analgesia as well.

[Case of large vein perforation caused by pumping using central venous catheter revealed by postoperative CT].

A 72-year-old woman, 157 cm in height and weighing 45 kg, was scheduled for emergency surgery for acute abdomen suggestive of gastrointestinal perforation. During the procedure, a triluminal central venous catheter (CVC) was inserted via the left internal jugular vein; venous blood could be aspirated separately through its lumens. On attempting blood transfusion, we noticed that the opening of one the CVC lumen tips was blocked and blood pumping was thus performed to achieve rapid transfusion. Colostomy was then performed and the transverse colon resection surgery was completed. Postoperative CT revealed right-sided hemothorax, a mediastinal hematoma located in the anterior region, and extravascular findings of CVC. The CT findings suggested a perforation of the left internal jugular vein due to the catheter tip. In the present case, the intraoperative pumping performed to enable rapid blood transfusion was believed to have caused blood vessel perforation. After the intraoperative blood vessel perforation, the condition may have been aggravated by steroid use, amyloidosis, and blood vessel fragility, ultimately presenting the extravascular findings observed on CT. We thus believe that in cases where CVC is inserted via the left internal jugular vein, blood pumping in particular is believed to be dangerous. Although the risks of blood vessel perforation when using CVC are relatively low, the possibility of unexpected complications should be borne in mind.

[Study of background factors of cerebral hyperperfusion syndrome in the anesthetic management of carotid endarterectomy].

BACKGROUND: We conducted a retrospective study to evaluate background factors of cerebral hyperperfusion syndrome (CHS) in the anesthetic management of carotid endarterectomy (CEA) for carotid artery stenosis. METHODS: A total of 118 ASA 1-2 adult patients were allocated to one of two groups: Group A of 13 patients who developed CHS after CEA, and Group B of the remaining 105 patients. We weighed control percent ratio of somatosensory evoked potential (%SEP). The rate of carotid artery stenosis, stump pressure of internal carotid artery, %SEP internal carotid artery blood flow (ICF), and preoperative anesthetic problems were compared between the two groups. RESULTS: The rate of carotid artery stenosis in Group A was 85%, significantly higher than 74% of Group B. Stump pressure in Group A was 28 mmHg, significantly lower than 37 mmHg of Group B. %SEP was 67% of Group A, and 87% of Group B, respectively ICF in Group A was 7+ +/- 33 ml min(-1), which decreaced significantly compared with 78 +/- 34 ml min(-1) of Group B. CONCLUSIONS: We conclude that the patients with high rate of carotid artery stenosis, low stump pressure and low ICF have a high risk of developing CHS after CEA and careful attention should be required in the anesthetic management of CEA.

[Effect of dexmedetomidine on intraoperative somatosensory evoked potential monitoring].

BACKGROUND: Intraoperative somatosensory-evoked potential (SEP) monitoring has become a part of neurosurgical procedures. In this study, we evaluated the effect of dexmedetomidine on SEP monitoring during neurosurgical anesthesia. METHODS: Eight patients scheduled for neurosurgery were studied. Anesthesia was maintained with continuous infusion of propofol at 2 microg x ml(-1) concentration using target controlled infusion (TCI). A loading dose of dexmedetomidine was infused at 6 microg x kg(-1) hr(-1) for 10 min and SEP was recorded. Infusion of dexmedetomidine was continued at 0.5 microg x kg(-1) x min(-1) for 10 min and SEP was recorded. We measured the change of amplitude and latency of SEP (N20-P25) and compared to baseline values. RESULTS: There was no statistically significant change in the cortical SEP amplitude (98.0 +/- 18.1% after a loading dose of dexmedetomidine and 112.7 +/- 16.8% at 0.5 microg x kg(-1) x min(-1) of dexmedetomidine, respectively) or latency (101.5 +/- 1.7% after a loading dose of dexmedetomidine and 101.9 +/- 1.7% at 0.5 microg x kg(-1) x min(-1) of dexmedetomidine, respectively). Mean blood pressure rose from 81 mmHg to 95 mmHg after initiation of dexmedetomidine infusion. Heart rate did not change. CONCLUSIONS: These findings suggest that dexmedetomidine has possibilities to produce an ideal environment as an anesthetic adjunct in patients requiring intrapoerative SEP monitoring.

[Effects of the injection method of lidocaine on preventing injection pain during anesthesia induction by target controlled infusion with propofol].

BACKGROUND: We conducted a prospective randomized study to assess the effects of preceding lidocaine on the incidence and intensity of propofol-induced pain. METHODS: A total of 360 ASA 1-2 adult patients were randomly allocated to one of six groups of 60 patients each: Group I pretreated with 2 ml saline, II pretreated with 2 ml lidocaine 2%, III pretreated with saline without infusion, IV pretreated with lidocaine without infusion, V pretreated with saline without infusion and restart infusion before propofol into a dorsal hand vein, or VI pretreated with lidocaine without infusion and restart infusion before propofol into a dorsal hand vein. Propofol-induced pain was assessed as none, mild, moderate, or severe. Anesthetic induction time and the hemodynamics were also recorded. RESULTS: Group IV and VI receiving lidocaine without infusion had a significantly lower incidence and intensity of moderate to severe pain compared with the other groups. Anesthetic induction time in Group III and IV was significantly longer than the other groups. There were no differences among all the groups in the hemodynamics during the induction. CONCLUSIONS: We conclude that pre-administration of lidocaine without infusion and restart infusion before propofol injecting into a dorsal hand vein is clinically useful.

Intrathecally administered COX-2 but not COX-1 or COX-3 inhibitors attenuate streptozotocin-induced mechanical hyperalgesia in rats.

Members of the cyclooxygenase (COX) family are known to catalyze the rate-limiting steps of prostaglandins synthesis and reported to be involved in neuropathic pain. Diabetic neuropathy is a type of neuropathic pain, though it is not clear if COX is relevant to the condition. Recently, spinal COX-2 protein was found to be increasing in streptozotocin-induced rats as compared to the constitutive expression. We attempted to determine which cyclooxygenase isoforms are involved in streptozotocin-induced mechanical hyperalgesia, which was induced by a single intraperitoneal injection of 75 mg/kg of streptozotocin. Intrathecal administrations of the COX-2 inhibitors SC-58125 (7-100 microg) and NS-398 (7-60 microg), as well as a high dose (100 microg) of the COX-1 inhibitor SC-560 attenuated hyperalgesia, whereas intrathecal administrations of a low dose (10 microg) of SC-560 and the COX-3 inhibitor acetaminophen (1-7 mg) did not. Further, intrathecal administration of SC-58125 (100 microg) did not produce an analgesic effect in normal rats. These results indicate that intrathecal administration of COX-2 inhibitors has an anti-hyperalgesic effect on streptozotocin-induced mechanical hyperalgesia and we concluded that spinal COX-2 is pivotal in streptozotocin-induced hyperalgesia.

Spinal orexin-1 receptors mediate anti-hyperalgesic effects of intrathecally-administered orexins in diabetic neuropathic pain model rats.

Orexin-A and orexin-B are endogenous ligands of orexin receptors that contain orexin-1 and orexin-2. Activation of the orexinergic system can produce antinociceptive effects in acute inflammatory, mono-neuropathic, and postoperative pain animal models, though the effects of orexins on diabetic neuropathic pain have not been previously investigated. In this study, we studied the anti-hyperalgesic effects of intrathecally administered orexins in a streptozotocin-induced diabetic rat. First, dose-dependent effects were investigated by measuring hind paw withdrawal thresholds in response to noxious-heat and punctate stimuli, after which orexin levels in the cerebrospinal fluid of diabetic rats were measured and compared with those of normal rats using a radioimmunoassay method. The functional role of spinal orexin-1 receptors with the anti-hyperalgesic effects of orexins was also investigated using intrathecal pretreatment with SB-334867, a selective orexin-1 receptor antagonist. Intrathecally administered orexins produced an antinociceptive effect in diabetic rats, however, not in normal rats, though the orexin levels in the cerebrospinal fluid of diabetic rats were similar to those in normal rats. In addition, the anti-hyperalgesic effects of orexins were significantly inhibited by pretreatment with SB-334867. These findings demonstrate that the anti-hyperalgesic effects of orexins in diabetic rats are unlikely due to any direct effect by the supplement on decreased endogenous orexins in the cerebrospinal fluid and that orexin-1 receptors in the spinal cord may be involved in the modulation of nociceptive transmission in diabetic neuropathy. We conclude that the spinal orexinergic system may be a possible target for elucidating the mechanisms of diabetes-induced hyperalgesia.

[Criteria for postoperative discharge of the patients managed by anesthesiologists in an ambulatory surgery unit].

BACKGROUND: Postoperative care following ambulatory surgery is done at home. Therefore, it is important to establish qualitative clinical discharge criteria that can be used to determine when patients can go home safely for the care by friend or relative. METHODS: This study included 213 patients who had been managed by anesthesiologist in an ambulatory surgery unit. We compared the discharge times achieved by post-anesthesia discharge scoring system with the times that the patients were actually discharged from the ambulatory surgery unit. RESULTS: On an average, patients who could be discharged safely on the same day required 161 minutes postoperatively to achieve a post-anesthesia discharge score of at least 9. The actual postoperative discharge time was 255 minutes. 53.6% of the patients who had been admitted could have obtained a post-anesthesia discharge score of at least 9, but they wanted to stay in hospital. CONCLUSIONS: A discharge scoring system is effective to determine the optimal length of stay in the ambulatory surgery unit and to achieve the prompt and safe discharge of patients. In order to popularize ambulatory surgery and reduce admission rate, it is necessary for us to make an effort to change patients' mind for ambulatory surgery.

Analgesic effect of intrathecal administration of orexin on neuropathic pain in rats.

Orexin-A, a hypothalamic peptide found in the neurons of the lateral hypothalamus, has been shown to modulate pain. We examined whether orexin could alleviate heat-evoked hyperalgesia in rats caused by chronic constriction injury (CCI) of the sciatic nerve. Orexin-A, orexin-B, the vehicle, or orexin-A-antiserum was intrathecally administered to CCI rats. Paw withdrawal latency (PWL) was measured from 30 to 300 minutes after injection, which was repeated for 2 days. Orexin-A administration normalized deltaPWL (PWL in the CCI side minus PWL in the control side) and inhibited heat-evoked hyperalgesia in CCI rats, while orexin-A antiserum inhibited the normalization of heat-evoked hyperalgesia caused by orexin-A two-fold. In contrast, orexin-B had no significant effect. These results suggest that orexin-A may be applicable for treatment of neuropathic pain.

[Postoperative continuous epidural analgesia with portable disposable infuser pump: review of 1500 cases].

BACKGROUND: We have been offering active postoperative analgesia service (PAS). In order to further enhance the quality of PAS, we reviewed 1500 cases of postoperative continuous epidural analgesia (PCEA). METHODS: Postoperative patients received epidural administration of a mixed analgesic solution employing bupivacaine, morphine, or fentanyl using a portable disposable infuser pump (PDIP) for at least 72 hours. Analgesic effects were assessed by using Prince Henry's scoring and the demand for additional analgesics. The frequency and causes of discontinued infusion were also evaluated. RESULTS: 83.9% of cases showed no complications. However, in 4.7% of cases infusion was discontinued because of side effects (nausea, vomiting, pruritus, lower limb motor block, and hypotension, etc.), in 4.1% because of dislodgment of the epidural catheter, in 3.4% because of disconnection, in 2.0% because the patient removing the catheter, and in 0.8% because of the condition of the catheter insertion site. CONCLUSION: These results indicate that to improve our method of PCEA with PDIP, we must re-assess our regimen used for continuous epidural infusion for postoperative pain relief, and develop measures to prevent side effects and complications.

[Assessment of preoperative anxiety in patients entering the operating room on foot using state-trait anxiety inventory].

The purpose of this prospective study was to assess the effect of walking into the operating room on preoperative anxiety level. Sixty non-premedicated patients scheduled for elective surgery were randomly divided into two groups based on how they were transported into the operating room. One group was carried on a stretcher (n = 30) and the other entered on foot under their own power (n = 30). A subjective assessment of anxiety was performed using a state-trait anxiety inventory (STAI) the day before surgery and on arrival at the operating room. STAI values were not increased in the operating room as compared to the day before surgery for either group and did not differ between groups, though they showed a high level of anxiety throughout the preoperative period. We conclude that walking into the operating room has no significant influence on preoperative anxiety level.