鈴木 万三

BACKGROUND: Maternal hypotension is a common hemodynamic consequence of spinal anesthesia during cesarean delivery, but low-dose spinal anesthesia (<9 mg bupivacaine) ensures stable hemodynamics and reduces motor block. The purpose of this retrospective observational study was to examine the effects of baricity of intrathecal administration of diluted bupivacaine in combined spinal-epidural anesthesia (CSEA) for cesarean delivery on maternal hypotension and motor block after surgery. METHODS: The anesthesia and nursing records of 35 patients who had given birth by cesarean delivery under CSEA with intrathecal administration of plain or hyperbaric bupivacaine diluted in cerebrospinal fluid were reviewed. All patients were assigned to who received hyperbaric bupivacaine (hyperbaric group) or plain bupivacaine (plain group). Definition of feasibility of cesarean delivery by diluted low dose bupivacaine was set as no requirement of epidural administration of levobupivacaine during surgery. The incidences of hypotension (nadir blood pressure less than 80% of preanesthetic value) and motor block were reviewed. RESULTS: In 24 of the patients (68%), no additional epidural anesthesia was needed during surgery. One patient (3%) required additional epidural anesthesia before delivery. Feasibility of cesarean delivery was not different between hyperbaric group and plain group (p>0.99). Eighteen of the patients (51%) did not require vasopressors, while 17 (49%) developed hypotension. There was no difference in incidence of maternal hypotension between hyperbaric and plain group. Only 6 patients (17%) required more than 3 times of administration of vasopressors among all patients. Modified Bromage scale scores were recorded in 28 of the patients (80%); scores of 0 (no motor block) were recorded in seven of them, and 1 in eight of them. CONCLUSION: Low-dose either plain or hyperbaric bupivacaine diluted in cerebrospinal fluid to approximately twice the volume may provide sufficient analgesia, fast motor recovery. Incidence of maternal hypotension was similar in hyperbaric and plain group.

The Sensmart Model X-100 (Nonin Medical Inc, Plymouth, MN, USA) is a relatively new device that possesses two sets of emitters and detectors and uses near infrared spectroscopy (NIRS) to measure regional cerebral oxygen saturation (rSO2). The value of rSO2 obtained by other NIRS devices is affected by physiological and anatomical variables such as hemoglobin concentration, area of cerebrospinal fluid (CSF) layer and skull thickness. The effects of these variables have not yet been determined in measurement of rSO2 by Sensmart Model X-100. We examined the effects of area of CSF, hemoglobin concentration, and skull thickness on the values of rSO2 measured by Sensmart Model X-100 and tissue oxygen index (TOI) measured by NIRO-200NX (Hamamatsu Photonix, Hamamatsu, Japan). Forty neurosurgical, cardiac and vascular surgical patients who underwent preoperative computed tomographic (CT) scan of the brain were enrolled in this study. Regional cerebral oxygen saturation (rSO2) at the forehead was measured sequentially by NIRO-200NX and by Sensmart Model X-100. Simultaneously, mean arterial pressure, hemoglobin concentration, and partial pressure of carbon dioxide in arterial blood (PaCO2) were measured. To evaluate the effects of anatomical factors on rSO2, we measured skull thickness and area of CSF layer using CT images of the brain. Multiple regression analysis was used to examine the relationships between the rSO2 values and anatomical and physiological factors. The area of the CSF layer and hemoglobin concentration had significant associations with rSO2 measured by the Sensmart Model X-100, whereas none of the studied variables was significantly associated with TOI. The measurement of rSO2 by Sensmart Model X-100 is not affected by the skull thickness of patients. Area of the CSF layer and hemoglobin concentration may be the main biases in measurement of rSO2 by Sensmart Model X-100.

Among patients who develop anaphylaxis during anesthesia, anaphylaxis caused by a neuromuscular blocking agent has the highest incidence. In patients who developed IgE-mediated anaphylaxis, and cross-reactivity among NMBAs is a concern in subsequent anesthetic procedures. We present a patient who developed rocuronium-induced anaphylaxis in whom the skin prick test (SPT) and intradermal test (IDT) could identify a safe drug to use in the subsequent anesthetic procedure. A 32-year-old female developed anaphylactic shock at the induction of general anesthesia. She recovered by administration of hydrocortisone and epinephrine. Skin tests including the SPT followed by the IDT revealed rocuronium as the drug that caused anaphylaxis and vecuronium as a safe drug to use for the subsequent general anesthesia. She safely underwent surgery with general anesthesia using vecuronium one month after the skin testing. There are not many reports on the effectiveness of the SPT followed by IDT in identifying the causative drug as well as a safe drug to use in the subsequent anesthetic procedure following anaphylaxis during anesthesia. The usefulness of the SPT should be re-evaluated.

Background: Surgical site infection (SSI) after colorectal surgery is the leading cause of postoperative morbidity. Opioids induce immunosuppression through activation of mu-opioid receptors expressed on leucocytes, and through opioid withdrawal. A high dose of opioid administered as remifentanil during surgery may induce immunosuppression, leading to the development of SSI. Aim: The purpose of this study was to investigate the influence of remifentanil on the development of SSI. Methods: Adult patients who underwent elective colorectal surgery from January 2009 to December 2012 (N = 286) were prospectively investigated according to the guidelines of the US Centers for Disease Control and Prevention. After exclusion of 51 patients, propensity matching was performed in 235 patients. To reduce the influence of selection on SSIs, propensity score pairwise matching was performed for patients maintained with remifentanil and for patients maintained with fentanyl. Findings: The number of patients who developed SSI was higher after remifentanil-based anaesthesia compared with fentanyl-based anaesthesia [11.6% (17/146) vs 3.4% (3/ 89), remifentanil vs fentanyl, P = 0.03] before propensity matching. Propensity matching yielded 61 pairs of patients anaesthetized with remifentanil or fentanyl, and corrected several biases in the preoperative patient characteristics. After propensity matching, the number of patients who developed SSI was still higher after remifentanil-based anaesthesia than after fentanyl-based anaesthesia [16.4% (10/61) vs 3.3% (2/61), remifentanil vs fentanyl, P = 0.029]. Conclusion: Remifentanil-based anaesthesia increased the incidence of SSI. A possible reason may be opioid-induced immunosuppression or opioid withdrawal-induced immunosuppression. (C) 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Introduction Low-dose ketamine infusion (blood concentration around 100 ng/mL) during surgery reduces the incidence of postoperative shivering after remifentanil-based anesthesia. We hypothesized that perioperative infusion of very low-dose ketamine (blood concentration around 40 ng/mL) during remifentanil-based anesthesia may also prevent the development of remifentanil-induced shivering during the 2-hour period after the end of anesthesia. Materials and methods Fifty female patients scheduled to undergo laparoscopic cystectomy or oophorectomy were assigned to one of two groups: (1) ketamine group, in which the patients received ketamine infusion (0.1 mg/kg/hour) from induction of anesthesia to emergence from anesthesia and (2) control group, in which the patients received saline infusion from induction up till emergence from anesthesia. Anesthesia was induced and maintained by target-controlled infusion of propofol (estimated blood concentration: 2-4 μg/mL) and infusion of remifentanil, at 0.2-0.3 μg/kg/minute. Patients were observed for shivering from the end of anesthesia to 120 minutes after anesthesia. The time point at which the patient began to shiver was recorded and assigned to one of four time periods: at emergence, from emergence to 30 minutes after anesthesia, from 30 minutes to 60 minutes after anesthesia, and &gt 60 minutes after anesthesia. Results During the 120-minute observation period, the number of patients who shivered was higher in the ketamine group than the in control group (18 vs. 8, ketamine group vs. control group, p = 0.01). The time period during which patients began to shiver was different between the two groups (1 patient, 4 patients, and 13 patients vs. 3 patients, 2 patients, and 3 patients at emergence, from emergence to 30 minutes, and from 30 minutes to 60 minutes after anesthesia, respectively ketamine group vs. control group, p = 0.007). Conclusion Intraoperative infusion of very low-dose ketamine during remifentanil-based anesthesia may increase the incidence of postoperative shivering. Copyright © 2013, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved.

体温加温装置を使用しない状況での保温用覆布として、吸湿発熱繊維であるアクリレート系繊維の有効性を検討するため、術中体温低下防止効果について、アクリレート系繊維単独で使用したアクリレート群とアクリレート系繊維をアルミ薄膜覆布に縫いつけたアクリレート+アルミ薄膜群を、アルミ薄膜覆布群とバスタオル群で比較検討した。入室時の室温を28℃に設定し、鼓膜、指先、前腕皮膚温を入室時、ならびに脊椎くも膜下麻酔施行後から15分おきに測定した。脊椎くも膜下麻酔施行後、直ちに保温用覆布で術野を除く四肢を覆い、手術中の室温を24.5℃とした。吸湿発熱繊維を使用した群では、バスタオル群に比べ中枢温の低下が軽減された。吸湿発熱繊維であるアクリレート系繊維による被覆は、術中の体温低下防止に有効であることが示唆された。(著者抄録)

Purpose of review In recent years, hundreds of studies have examined the clinical efficacy of N-methyl-D-aspartate (NMDA) receptor antagonists such as ketamine and dextromethorphan as an adjunct to routine postoperative pain management. The purpose of this review is to a describe the detail of the study that successfully demonstrated the efficacy of NMDA receptor antagonists. Recent findings The effect of perioperative ketamine infusion, dextromethorphan, and memantine on postoperative opioid-induced analgesia and prevention of long-term persistent pain is described. Summary The co-administration of ketamine and morphine as a mixture is not recommended for postoperative pain relief. As an adjunct in multimodal analgesia, low-dose ketamine infusion and the administration of dextromethorphan may be able to improve postoperative pain status. Memantine exhibits the greatest potency among NMDA receptor antagonists. In future, research should consider the perioperative infusion of ketamine followed by long-term administration of memantine for the prevention of persistent pain.

Study Objective: To determine whether administration of pre-warmed colloid followed by pre-warmed crystalloid solution prevents the development of hypothermia in patients undergoing Cesarean delivery. Design: Randomized, double-blind, placebo-controlled study. Patients: 30 parturients scheduled to undergo elective Cesarean delivery during spinal anesthesia. Interventions: Patients assigned to the warmed fluid group (n = 15) received pre-warmed colloid with average molecular weight of 70,000 daltons and substitution ratio of 0.55, followed by pre-warmed crystalloid (kept in warmed storage maintained at 41 degrees C) during surgery. Patients assigned to the unwarmed fluid group (n = 15) received non-warmed infusion. All patients received 400 mL before spinal anesthesia followed by another 300 mL before delivery of the newborn. After completion of a 1,000 mL infusion of colloid fluid, acetate Ringer&apos;s solution was infused. Measurements: Core temperature measured at the tympanic membrane, and forearm and fingertip skin temperatures were recorded just after arrival at the operating room (baseline), after administration of spinal anesthesia (spinal), at incision (incision), at delivery of the newborn, (delivery), and at 15, 30, and 45 minutes after delivery. Rectal temperature of the baby, Apgar scores at one and 5 minutes after delivery, and umbilical artery pH were evaluated. Main Results: Core temperature was significantly higher in the unwarmed fluid group from the time of delivery to 45 minutes after delivery. Apgar scores at one minute after delivery and umbilical arterial pH were significantly higher in the warmed fluid group.

Controlling acute postoperative pain remains a challenge amelioration of pain affects not only postoperative mobility and mortality, but also the incidence of chronic pain after surgery. Tissue injury from surgery leads to release of inflammatory mediators that activate peripheral nociceptors. Nociceptive information travels thorough A-δ and C fibers to the spinal dorsal horn and creates a reduction in the threshold for activation in the dorsal horn, which is called central sensitization. N-methyl-D-aspertate (NMDA) receptors are located presynaptically, and postsynaptically the increase nociceptive pain transmission and play a crucial role in the development of central sensitization. Ketamine, a phencyclidine derivative that possesses a substantial analgesic effect, has been used for intravenous (IV) anesthesia for more than 3 decades. In recent years, hundreds of articles have emphasized the analgesic, preemptive, and antihyperalgesic effects of ketamine. However, from the standpoint of improving pain outcome, the clinical use of ketamine is still controversial. Evidence from several studies strongly suggests that the effect of ketamine appears to depend on the type and duration of surgery, impact on nociception by surgical manipulation, type of basic pain treatment, and duration and amount of ketamine administered. By using ketamine effectively, we may reduce the pain score after surgery, decreasemorphine consumption, and reduce the incidence of long-termpersistent pain after major surgery. In this chapter, I describe the method for effective administration of ketamine to improve outcome with regard to pain.

The combination of general anesthesia and epidural anesthesia has been considered to worsen the degree of hypothermia. However, epidural anesthesia reduces cardiac output, which may prevent redistribution hypothermia. Twenty-four patients undergoing gynecologic surgery were randomly assigned to one of two groups: recipients of epidural injection of 1% ropivacaine and general anesthesia (epidural and general group, n=12) and recipients of epidural injection of saline and general anesthesia (general group, n=12). Fifteen minutes after epidural injection of 12 mL of 1% ropivacaine (epidural and general group) or saline (general group), general anesthesia was induced with propofol, and tracheal intubation was facilitated with vecuronium. Anesthesia was maintained with 35% oxygen and 0.4% to 2% isoflurane with a nitrous oxide mixture. Tympanic (core), forearm, and fingertip temperatures were recorded before the epidural injection, just before induction of general anesthesia, just after tracheal intubation, and every 15 minutes up to 90 minutes after tracheal intubation. The core temperature was significantly higher in the epidural and general group than in the general group from 30 to 90 minutes after tracheal intubation. Epidural anesthesia with 1% ropivacaine may prevent redistribution hypothermia during general anesthesia for gynecologic surgery.

Background: A common problem during lung separation is malposition of the double-lumen tube (DLT). It was hypothesized that inflation of the distal cuff with saline instead of air may reduce the incidence of malposition of the endobronchial tube. Materials and Methods: Fifty-two patients who were scheduled to undergo thoracic surgery with lung separation by a DLT were randomly assigned to 1 of 2 groups: the distal cuff was inflated with 2 mL of air in the air group (n = 26), whereas the distal cuff was inflated with 1.2 mL of saline in the saline group (n = 26). Anesthesia was maintained by isoflurane, 50% oxygen and nitrous oxide mixture, and incremental injection of epidural ropivacaine, 0.75%. Respiration was controlled by pressure-controlled ventilation. The peak airway pressure was maintained between 20 to 25 cmH(2)O. The position of the bronchial cuff was evaluated with a fiberoptic bronchoscope just after intubation and 1 and 2 hours after intubation by using a 3-point scale: 0, in exactly the same position as the previous inspection; 1, not in exactly the same position as that in the previous inspection, but there was no possibility that the tube was malpositioned; and 2, the cuff looked as if it was going to become herniated or dislodged. Signs suggesting malposition such as air leakage, high airway pressure, or inflation of the independent lung were recorded. When repositioning was required, the anesthesiologist repositioned the DLT using bronchoscopic observation or clinical signs. The endpoint of this study was the number of patients who required repositioning during surgery. Results: The malposition score at 1 hour and 2 hours after intubation was comparable in the 2 groups (0.6 +/- 0.6 v 0.4 +/- 0.6 and 0.5 +/- 0.8 v 0.2 +/- 0.5, mean +/- standard deviation, air group v saline group, 1 hour and 2 hours after positioning, p = 0.27 and p = 0.33, respectively). However, a significantly higher cumulative number of air-group patients required repositioning of the tube than saline-group patients (13:6, air group:saline group, p = 0.04). Conclusion: Inflation of the distal cuff with saline may reduce the incidence of malpositioning of DLTs during lung separation. (C) 2007 Elsevier Inc. All rights reserved.

Background. Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain. Methods: Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg (.) kg(-1) (.) h(-1) [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in dally life at 7 days and 1, 3, and 6 months after surgery. Results: The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 11 vs. 25 +/- 20 and 9 +/- 11 as. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean SD; P = 0.002 and P = 0.01, P &lt; 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] us. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03). Conclusions: Very-low-dose ketamine (0.05 mg - kg(-1) - h(-1)) potentiated morphine-ropivacaine analgesia and reduced postthoracotomy pain.

We report a case of cervical spondylitis that developed during treatment with a series of stellate ganglion blocks. A 65-year-old man was scheduled for 10 sessions of stellate ganglion block for treatment of right-sided deafness of sudden onset due to Ramsay Hunt syndrome. Administration of betamethasone was started 5 days before the first block and was continued for 6 weeks. After disinfection of the skin by povidone iodine, each stellate ganglion block was performed via the paratracheal approach. The first four block sessions were uneventful. However, during the fifth session, the patient complained of neck pain. After 10 sessions, the deafness improved and the patient was discharged from the hospital. Three weeks after discharge, he was readmitted for sustained neck and bilateral shoulder pain and numbness of the right hand. Cervical roentgenography and magnetic resonance imaging revealed spondylitis of C5 and C6. Antibiotics were administered for 2 weeks. The inflammatory variables on blood examination improved, but cervical roentgenography performed 8 weeks after the last block showed that the vertebral body of C6 was nearly completely destroyed. Four months after the last block, the vertebral bodies of C5 and C6 had fused. This case indicates that when stellate ganglion block is performed in patients who are taking a corticosteroid, the disinfection procedure must be strictly followed and that if the patient complains of neck or shoulder pain, cervical roentgenography or magnetic resonance imaging or both should be immediately performed to assess the presence of spondylitis.

We measured the blood concentration of propofol in a patient with delayed emergence from propofol-nitrous oxide anesthesia. A 78-year-old man underwent subtotal gastrectomy under both epidural and propofol-nitrous oxide anesthesia and did not regain consciousness soon after termination of propofol infusion. Preoperative laboratory examination revealed anemia and a low blood total protein concentration, but there was no evidence of impaired liver function. While the anesthesiologists were waiting for the patient to regain consciousness, a surgeon mentioned that the common hepatic artery might have been occluded during surgical manipulation. Arterial blood samples were obtained 50 and 80 minutes after termination of propofol infusion, and the blood concentration of propofol was measured. We considered that clearance of propofol through the hepatic route may have been impaired however, the actual blood concentrations of propofol were not significantly increased compared with the respective blood concentrations obtained in the simulation. Therefore, the acute liver damage did not significantly impair elimination of propofol. Because most propofol molecules in the blood bind to proteins and erythrocytes, it is suspected that the anemia and low blood total protein concentration led to an increase in the free fraction of propofol in the blood, thereby delaying emergence from anesthesia.

N-methyl-D-aspartate (NMDA) receptor antagonists enhance opioid-induced analgesia. The plasma concentration of ketamine, an NMDA receptor antagonist that enhances epidural morphine-and-bupivacaine-induced analgesia, is not known. We examined 24 patients with lung carcinoma or metastatic lung tumor who underwent video-assisted thoracic surgery in a placebo-controlled, double-blind manner 4 h after emergence from anesthesia. The morphine + ketamine group (n = 8) and morphine + placebo group (n = 8) received 5 mL volume of 2.5 mg morphine and 0.25% bupivacaine and the placebo + ketamine group (n = 8) received 5 mL volume of saline and 0.25% bupivacaine epidurally at the end of skin closure. Four hours after this anesthesia, in the morphine + ketamine and placebo + ketamine groups, ketamine was administered to successively maintain a stable plasma ketamine concentration of 0, 10, 20, 30, 40, and 50 ng/mL by a target-controlled infusion device, and patients assessed the levels of pain at rest, pain on coughing, somnolence (drowsiness), and nausea using a 100-mm visual analog scale (VAS). In the morphine + placebo group, a placebo (saline) was similarly administered instead of ketamine. In the morphine + ketamine group, the VAS scores for pain at rest and pain on coughing significantly decreased on ketamine administration at a plasma concentration of 20 ng/mL or larger compared with the respective baseline VAS scores (P &lt; 0.05 each). In the placebo + ketamine group, the VAS scores for pain at rest and pain on coughing did not significantly change at any plasma concentration of ketamine as compared to the morphine + placebo group. In the morphine + ketamine group, a plasma concentration of ketamine larger than 20 ng/mL did not further reduce VAS scores for pain at rest and pain on coughing. The VAS scores for drowsiness were comparable among the three groups at any plasma concentration of ketamine. Ketamine at a plasma concentration of 20 ng/mL or larger may enhance epidural morphine-and-bupivacaine-induced analgesia. As an adjunct with epidural morphine-and-bupivacaine and considering the safety of small doses, the minimal plasma concentration of ketamine given IV may be approximately 20 ng/mL.

Carbon dioxide insufflation during laparoscopic surgery may interfere with the accuracy of the cardiac output value measured by the NICO2™ system. The authors simultaneously measured cardiac output by the thermodilution method and by the carbon dioxide rebreathing technique during laparoscopic adrenalectomy in a patient with a nonfunctional adrenal tumor. There was a strong correlation between the cardiac output values measured by the two methods. This case report suggests that the carbon dioxide rebreathing technique can be used to monitor cardiac output during laparoscopic surgery. ©2005 by the International Anesthesia Research Society.

Purpose: The first sacral nerve has the largest diameter among the spinal nerves and is resistant to local anesthetics. Ropivacaine is a newly developed local anesthetic. There is a possibility that a difference in chemical properties between ropivacaine and other local anesthetics produces a difference in the blockade of the S1 dermatome by lower thoracic epidural anesthesia. Mepivacaine, 2%, is frequently used for epidural anesthesia and produces a level of blockade similar to that of bupivacaine, 0.5%. The purpose of this study was to examine the sensory blockade in the sacral region induced by ropivacaine with that induced by mepivacaine administered in the lower thoracic epidural space. Methods: Eighteen adults undergoing lower thoracic epidural anes thesia (thoracic 11/12 interspace) were studied in a double-blind fashion. Patients were assigned to one of two groups: those who received 2% mepivacaine, 18 ml (group M n = 9), and those who received 1% ropivacaine, 12 ml (group R n = 9). The cephalad levels of sensory blockade to cold, pinprick, and touch in the L2, S1, and S3 dermatomes were assessed at 10, 20, and 35 min after injection. Results: There wer e no differences in the cephalad levels of sensory block to cold (T4 [range, T4-T2] and T4 [range, T6-T2]), pinprick (T4 [range, T6-T4] and T4 [range, T6-T4]), or touch (T6 [range, T6-T4] and T6 [range, T6-T4]) between group M and group R respectively, at 35 min (P &gt 0.05). In the L2 and S3 dermatomes, there were no significant differences in the numbers of patients who obtained sensory block to cold or pinprick at 20 and 35 min after study drug administration. However, in the S1 dermatome, significantly higher numbers of patients in group R obtained sensory block to cold at 20 and 35 min after study drug administration than in group M (8 and 0 9 and 0 P = 0.001 and P &lt 0.001 20 min and 35 min after administration, respectively). Also in the S1 dermatome, significantly higher numbers of patients in group R obtained sensory block to pinprick at 20 and 35 min after study drug administration than in group M (6 and 0 9 and 0 P = 0.027 and P &lt 0.001 20 min and 35 min after administration, respectively). A significantly higher number of patients in group R had sensory block to touch in the S3 dermatome at 35 min (7 and 2 group R and group M, respectively P = 0.01). Conclusion: Ropivacaine, 1%, administered in the lower thoracic epidural space, induces sensory blockade to cold and pinprick in the S1 dermatome more frequently than 2% mepivacaine. © JSA 2004.

Mild hypothermia is a common complication during spinal anesthesia and may induce a serious adverse outcome. We investigated the effect of low-dose ketamine infusion on the core temperature during spinal anesthesia sedated by propofol infusion. Twenty patients who were scheduled to undergo spinal anesthesia were assigned to one of two groups: after intrathecal injection of bupivacaine, patients who received infusion of ketamine (0.3 mg/kg/hr) and propofol (initial rate of 10 mg/kg/hr) (KP group), and patients who received infusion of placebo (saline) and propofol (initial rate of 10 mg/kg/hr) (P group). The rate of propofol administration was reduced as much as possible while maintaining sedation with an OAA/S score of 3 or below. The core temperature, forearm temperature, and fingertip temperature were recorded before spinal anesthesia, and just before (baseline) and 15, 30, 45, and 60 minutes after the start of propofol administration. The core temperature, reduction in core temperature from baseline (delta CT), and forearm-fingertip temperature gradient were compared between the two groups. In the P group, the core temperature linearly decreased over time. The core temperature at 30, 45, and 60 minutes was significantly higher in the KP group than in the P group (36.3±0.2 and 35.9±0.3, at 60 minutes, mean±SD, p&lt 0.05). The delta CT at 15, 30, 45, and 60 minutes was significantly smaller in the KP group than in the P group. There were no significant differences in the forearm-fingertip temperature gradient between the two groups over the study period. In conclusion, low-dose ketamine administration may confer thermoprotection during spinal anesthesia sedated by propofol.

Purpose: To determine the effects of midazolam, 30 ng·mL-1, on altered perception, mood, and cognition induced by ketamine. Methods: After ketamine was administered to achieve target concentrations of 50, 100, or 150 ng·mL-1in 11 volunteers, perception, mood and thought process were assessed by a visual analog scale. Mini-Mental State examination (MMSE) assessed cognition. Boluses of midazolam, 30, 14.5, and 12 μg·kg-1, were injected every 30 min to maintain the plasma concentration at 30 ng·mL-1, which was reached 30 min after each injection. Results: Ketamine produced changes in perception about the body (P &lt; 0.01, 0.001, and 0.0001 at 30, 60, and 90 min), surroundings (P &lt; 0.01 and 0.0001 at 60 and 90 min), time (P &lt; 0.002 and 0.0001 at 60 and 90 min), reality (P &lt; 0.001 and 0.0001 at 60 and 90 min), sounds (P &lt; 0.002 at 90 min), and meaning (P &lt; 0.05 at 90 min). Subjects felt less energetic and clearheaded (P &lt; 0.02 and 0.05) during ketamine, midazolam, and their co-administration. Ketamine impaired thought process (P &lt; 0.003 and 0.0001 at 60 and 90 min). Ketamine and midazolam decreased mean total MMSE and recall scores (P &lt; 0.001 for both). Co-administration reduced the number of subjects with perceptual (body P &lt; 0.01 and 0.001 at 30 and 60 min) and thought process abnormalities. Within the range of observation co-administration did not affect the changes in mood or recall. Conclusion: Midazolam attenuates ketamine-induced charges in perception and thought process.

Small-dose ketamine may enhance the analgesic effect of opiates. We studied the effect of IV coadministration of small-dose ketamine 50-100 mu g/kg with morphine 50 mu g/kg on postoperative morphine requirements and pain in 140 patients undergoing outpatient surgery, Midazolam 1-2 mg was administered in the holding area. Anesthesia was induced with propofol 2-2.5 mg/kg and was maintained with desflurane in a nitrous oxide/oxygen mixture. Patients received morphine 50 mu g/kg with placebo (Group 1, n = 35) or ketamine 50 mu g/kg IV (Group 2, n = 35), 75 mu g/kg IV (Group 3, n = 35), or 100 mu g/kg IV (Group 4, n = 35) 15 min before the end of the operation. Pain and drowsiness were assessed using visual analog scales on arrival in the recovery room, then every 15 min until the time of discharge to phase 2 recovery (phase 1 recovery), Morphine consumption in Groups 3 and 4 was approximately 40% less than that in the control group (91 +/- 9 and 89 +/- 8 mu g/kg vs 125 +/- 9 mu g/kg; P &lt; 0.05 for both). Pain scores in Groups 3 and 4 were approximately 35% less than those in the control group at all time periods (P &lt; 0.0001 for all). There was no significant group difference in drowsiness scores. Small-dose ketamine 75-100 mu g/kg IV, enhanced morphine-induced analgesia after outpatient surgery. Simultaneous use of small doses of ketamine with morphine enhances the pain relief produced by morphine. Implications: Simultaneous use of small doses of ketamine with morphine enhances the pain relief produced by morphine.