The effect of 6% hydroxyethyl starch 130/0.4 preloading on the blood glucose levels in diabetic patients undergoing orthopedic surgery with spinal anesthesia: a randomized pilot study.

BACKGROUND: Perioperative hyperglycemia can occur in surgical patients and may increase postoperative morbidity and mortality, especially in patients with diabetes. Therefore, we conducted the present study to evaluate whether the administration of 6% hydroxyethyl starch (HES)-130/0.4 increases blood glucose levels in patients with diabetes. METHODS: Forty patients undergoing lower limb surgery under spinal anesthesia were randomly allocated into two groups according to the fluids administered 20 min before spinal anesthesia (Group L, lactated Ringer's solution; Group H, 6% HES-130/0.4). Patient characteristics, intraoperative variables, blood glucose levels, mean blood pressure (MBP), and heart rate (HR) were recorded at five time-points (0, 20, 60, 120, and 240 min). RESULTS: A total of 39 patients were analyzed (Group L, n = 20; Group H, n = 19). The amount of intraoperative fluid was significantly higher in Group L than in Group H (718.2 ml vs. 530.0 ml, P = 0.010). There were no significant differences in the changes in blood glucose levels, HR, or MBP between the two groups (P = 0.737, P = 0.896, and P = 0.141, respectively). Serial changes in mean blood glucose levels from baseline also showed no significant differences between the groups (P = 0.764). CONCLUSIONS: There were no significant changes in blood glucose levels when lactated Ringer's solution or 6% HES-130 was used. When compared to the lactated Ringer's solution, no evidence that 6% HES-130/0.4 produces hyperglycemia in diabetic patients could be found. Further evaluation of larger populations is needed.

Effect of gastric decompression on postoperative vomiting in pediatric patients undergoing strabismus surgery: a randomized controlled study.

BACKGROUND: Postoperative vomiting (POV) is one of the most serious complications in pediatric patients undergoing strabismus surgery. This study was conducted to test the hypothesis that gastric decompression (GD) could prevent POV caused by gastric distension after mask ventilation. METHODS: A total of 60 pediatric patients (ASA PS I-II, aged one to 10 years) were randomly allocated to two groups; Group D (n = 30) and Group C (n = 30). Induction of anesthesia was performed with careful face mask ventilation with 100% O2 (3 L/min) and sevoflurane 3 vol% to limit airway pressure below 20 cmH2O. Endotracheal intubation was done after confirming adequate neuromuscular blockade. Then, the patients in Group D received GD, while patients in Group C did not. After the surgery, POV was assessed during the emergence from anesthesia in the operating room and postanesthetic care unit (30 min and 60 min). RESULTS: During the emergence, POV was significantly decreased in Group D compared to Group C (Group D 3.3% vs. Group C 30.0%, P = 0.006). The odds ratio analysis showed a lower incidence of POV in Group D (odds ratio = 0.080; 95% confidence limit: 0.009-0.685) during the emergence period. There was no significant difference in the incidence of POV in the postanesthetic care unit (Group D 6.7% vs. Group C 4.3% at 30 min, P = 1.000; 0% in both groups at 60 min). CONCLUSIONS: GD reduced the incidence of POV in pediatric patients undergoing strabismus surgery during emergence.

The relaxant effect of nicardipine on the isolated uterine smooth muscle of the pregnant rat.

BACKGROUND: Nicardipine, a calcium channel blocker, is used to treat hypertension in pregnancy or preterm labor. The current study was conducted to investigate the relaxant effects of nicardipine on the isolated uterine smooth muscle of the pregnant rat. METHODS: We obtained uterine smooth muscle strips from pregnant female SD rats. After uterine contraction with oxytocin 10 mU/ml, we added nicardipine (10-12 to 10-8 M) accumulatively every 20 min. We recorded active tension and frequency of contraction, and calculated EC5 (effective concentration of 5% reduction), EC25, EC50, EC75, and EC95 of active tension and frequency of contraction using a probit model. RESULTS: Nicardipine (10-12 to 10-8 M) decreased active tension and frequency of contraction in a concentration-dependent manner. The EC50 and EC95 of nicardipine in the inhibition of active tension of the uterine smooth muscle were 2.41 × 10-10 M and 3.06 × 10-7 M, respectively. The EC50 and EC95 of nicardipine in the inhibition of frequency of contraction of the uterine smooth muscle were 9.04 × 10-11 and 4.18 × 10-7 M, respectively. CONCLUSIONS: Nicardipine relaxed and decreased the frequency of contraction of the uterine smooth muscle in a concentration-dependent pattern. It might be possible to adjust the clinical dosage of nicardipine in the obstetric field based on our results, but further clinical studies are needed to confirm them.

Experimental comparison of performances of Mega Acer Kit, Ranger and ThermoSens according to flow rates and distances.

We experimentally investigated the fluid warming performances of three warmers with different technology, according to flow rates and distances. We used the following intravenous fluid warmers: Mega Acer Kit (Group M, n = 8), Ranger (group R, n = 8), and ThermoSens (group T, n = 8). Fluids that had been stored in the operating room over the previous 24 h were delivered at sequent flow rates of from 440 mL/h up to 2500 mL/h through preheated warming devices. The fluid temperatures were recorded at the inlet point, 76-cm proximal (Pout1) and 166-cm distal outlet points (Pout2) every 1 min for 10 min. We repeated each test eight times. The delivered fluid temperature [mean (95% confidence interval)] was significantly higher in group M than group R and T at flow rates up to 650 mL/h with the highest value at 440 mL/h [34.30 (33.35-35.24)°C] (P < 0.001), and was higher in group T and R at flow rates over 1140 mL/h at Pout1 [36.67 (36.62-36.73)°C and 37.85 (37.52-38.17)°C at 2500 mL/h, respectively] (P < 0.001). It was significantly higher at the Pout1 than the Pout2 at all flow rates for each device (P < 0.001). Mega Acer Kit can warm fluid more effectively compared with ThermoSens and Ranger at the low flow rate whereas the ThermoSens and the Ranger are suitable at higher flow rates. Furthermore, the device performance is more effective with shorter extension lines.

Mega Acer Kit® is more effective for warming the intravenous fluid than Ranger™ and ThermoSens® at 440 ml/h of infusion rate: an experimental performance study.

BACKGROUND: Few studies have investigated the effectiveness of intravenous fluid warmers at low and moderate flow rates below 1,000 ml/h. In this study, we compared the effectiveness of three different fluid warmers at a low flow rate (440 ml/h). METHODS: We experimentally investigated the fluid warming performances of Mega Acer Kit® (Group M, n = 10), Ranger™ (Group R, n = 10), and ThermoSens® (Group T, n = 10) at 440 ml/h for 60 min. All devices were set at a warming temperature of 41℃ with preheating for 10 min. Intravenous fluids were then delivered through them. The fluid temperature (primary endpoint) was measured at 76 cm from the device after infusion for 60 min. The expected decrease in mean body temperature (secondary endpoint) after 5 h infusion for a 70 kg patient (ΔMBT5) was also calculated. RESULTS: The fluid temperature (mean [95% CI]) at 76 cm from the device, 60 minutes after the infusion was higher in group M (36.01 [35.73-36.29]℃), compared to groups T (29.81 [29.38-30.24]℃) and R (29.12 [28.52-29.72]℃) (P < 0.001). The ΔMBT5 (mean [95% CI]) was significantly smaller in group M (-0.04 [-0.04 to -0.03]℃) than that in groups T (-0.27 [-0.28 to -0.29]℃; P < 0.001) and R (-0.30 [-0.32 to -0.27]℃; P < 0.001). However, none of the fluid warmers provided a constant normothermic temperature above 36.5℃. CONCLUSIONS: Mega Acer Kit® was more effective in warming the intravenous fluid with the smallest expected change in the mean body temperature, compared to Ranger™ and ThermoSens®, at a flow rate of 440 ml/h.

Effect of hydroxyethyl starch on blood glucose levels.

BACKGROUND: Hydroxyethyl starch (HES), a commonly used resuscitation fluid, has the property to induce hyperglycemia as it contains large ethyl starch, which can be metabolized to produce glucose. We evaluated the effect of 6% HES-130 on the blood glucose levels in non-diabetic patients undergoing surgery under spinal anesthesia. METHODS: Patients scheduled to undergo elective lower limb surgery were enrolled. Fifty-eight patients were divided into two groups according to the type of the main intravascular fluid used before spinal anesthesia (Group LR: lactated Ringer's solution, n = 30 vs. Group HES: 6% hydroxyethyl starch 130/0.4, n = 28). Blood glucose levels were measured at the following time points: 0 (baseline), 20 min (T1), 1 h (T2), 2 h (T3), 4 h (T4), and 6 h (T6). RESULTS: Mean blood glucose levels at T5 in the LR group and T4, T5 in the HES group, increased significantly compared to baseline. There were no significant changes in the serial differences of mean blood glucose levels from baseline between the two groups. CONCLUSIONS: Administration of 6% HES-130 increased blood glucose levels within the physiologic limits, but the degree of glucose increase was not greater than that caused by administration of lactated Ringer's solution. In conclusion, we did not find evidence that 6% HES-130 induces hyperglycemia in non-diabetic patients.

Effects of lidocaine, ketamine, and remifentanil on withdrawal response of rocuronium.

BACKGROUND: Rocuronium has been well known to produce withdrawal response in 50-80% patients when administered intravenously. Several drugs are administered prior injection of rocuronium to prevent the withdrawal response. We compared the preventive effect of lidocaine, ketamine, and remifentanil on the withdrawal response of rocuronium. METHODS: A total of 120 patients undergoing various elective surgeries were enrolled. Patients were allocated into 4 groups according to the pretreatment drugs (Group N, normal saline; Groups L, lidocaine 40 mg; Group K, ketamine 0.5 mg/kg; Group R, remifentanil 1 µg/kg). Patients received drugs prepared by dilution to 3 ml volume before injection of rocuronium. Withdrawal responses after injection of rocuronium were graded on a 4-point scale. Hemodynamic changes were observed before and after administration of pretreatment drugs and after endotracheal intubation. RESULTS: Incidence of withdrawal response was significantly lower in group L (20%), group K (30%), and group R (0%), than group N (87%). Severe withdrawal response was observed in 5 of the 30 patients (17%) in group L, and in 9 of the 30 patients (30%) in group K. There was no severe withdrawal response in group R. Mean blood pressure and heart rate were significantly decreased in group R compared to other groups. CONCLUSIONS: It seems that remifentanil (1 µg/kg intravenously) was the strongest and most effective in prevention of withdrawal response after rocuronium injection among the 3 drugs.

Effect on thermoregulatory responses in patients undergoing a tympanoplasty in accordance to the anesthetic techniques during PEEP: a comparison between inhalation anesthesia with desflurane and TIVA.

BACKGROUND: It has been known that positive end-expiratory pressure (PEEP) increases the vasoconstriction threshold by baroreceptor unloading. We compared the effect on the thermoregulatory responses according to anesthetic techniques between an inhalation anesthesia with desflurane and a total intravenous anesthesia (TIVA) with propofol and reminfentanil when PEEP was applied in patients undergoing tympanoplasty. METHODS: Forty-six patients with a scheduled tympanoplasty were enrolled and the patients were divided in two study groups. Desflurane was used as an inhalation anesthetic in group 1 (n = 22), while TIVA with propofol and remifentanil was used in group 2 (n = 24). PEEP was applied by 5 cmH2O in both groups and an ambient temperature was maintained at 22-24℃ during surgery. The core temperature and the difference of skin temperature between forearm and fingertip were monitored for about 180 minutes before and after the induction of general anesthesia. RESULTS: The final core temperature was significantly higher in group 2 (35.4 ± 0.7℃) than in group 1 (34.9 ± 0.5℃). Peripheral thermoregulatory vasoconstriction was found in 5 subjects (23%) in group 1 and in 21 subjects (88%) in group 2. The time taken for reaching the thermoregulatory vasoconstriction threshold was 151.4 ± 19.7 minutes in group 1 and 88.9 ± 14.4 minutes in group 2. CONCLUSIONS: When PEEP will be applied, anesthesia with TIVA may have more advantages in core temperature preservation than an inhalation anesthesia with desflurane.

A comparison of the clinical duration and recovery characteristics of cisatracurium after priming using rocuronium or cisatracurium: preliminary study.

BACKGROUND: The priming technique can speed up the onset of cisatracurium during intubation. However, there have been no reports on the effect of the priming technique on duration or recovery profile of cisatracurium. Therefore, we attempted to determine whether or not a priming technique with rocuronium or cisatracurium can affect clinical duration or recovery profiles of cisatracurium. METHODS: A total of 36 patients, ASA I and II, who were scheduled to undergo elective surgery, were enrolled. The patients were randomized into three groups and administered different drugs for the priming technique. Patients in group 1 received normal saline (control group). Patients in group 2 received rocuronium (0.06 mg/kg), and those in group 3 received cisatracurium (0.01 mg/kg) as a priming agent. Three minutes after injection of drugs, intubation doses of cisatracurium were administered (Group 1, 0.15 mg/kg; Groups 2 and 3, 0.14 mg/kg). Anesthesia was induced and maintained with propofol and remifentanil. Onset time, clinical duration, recovery index, recovery time, and total recovery time were measured by train of four monitoring. RESULTS: Onset time in the group 2 was significantly shorter than that of group 1 or 3 (P < 0.05). However, no significant differences in clinical duration, recovery index, recovery time, and total recovery time were observed among the three groups. CONCLUSIONS: Priming with rocuronium for 3 minutes resulted in significantly accelerated onset of cisatracurium. However, it did not affect the clinical duration and recovery profiles of cisatracurium.

Effects of tidal volume and PEEP on arterial blood gases and pulmonary mechanics during one-lung ventilation.

PURPOSE: The main problem of one-lung ventilation (OLV) is hypoxemia. The use of a high tidal volume for preventing hypoxemia during OLV is controversial. We compared the effects of a high tidal volume versus a low tidal volume with or without PEEP on arterial oxygen tension (PaO(2)) and pulmonary mechanics during OLV. METHODS: Sixty patients (age range, 16-65 years; ASA I, II) who underwent wedge resection with video-assisted thoracostomy during OLV were assigned to three groups: group I received a high tidal volume (10 ml/kg) (n = 20), group II received a low tidal volume (6 ml/kg) (n = 20), and group III received a low tidal volume (6 ml/kg) with PEEP (5 cmH(2)O) (n = 20). Patient hemodynamics, pulmonary mechanics, and arterial blood gases were measured before (T(0)) OLV and 5 (T(1)), 15 (T(2)), 30 (T(3)), and 45 min (T(4)) after OLV. RESULTS: The PaO(2)/FiO(2) ratios of group II and III were significantly decreased and the incidence of hypoxemia was significantly higher in groups II and III than in group I (P < 0.05). CONCLUSION: During OLV, mechanical ventilation with a low tidal volume with or without PEEP increased hypoxemia as compared to that when performing OLV with a high tidal volume.

Effects of PEEP on the thermoregulatory responses during TIVA in patients undergoing tympanoplasty.

BACKGROUND: During general anesthesia, core temperature decreases, largely due to heat loss caused by peripheral vasodilation, resulting in heat redistribution to peripheral tissues. Multiple factors contribute to body temperature regulation during general anesthesia. It was reported that baroreceptor unloading by positive end-expiratory pressure (PEEP) attenuates anesthetically-induced hypothermia. So, we evaluated the effects of PEEP on thermoregulatory responses during total intravenous anesthesia (TIVA). METHODS: Forty healthy patients scheduled for tympanoplasty were allocated two groups, Group ZEEP (zero end-expiratory pressure, n = 20) and Group PEEP (PEEP application of 5 cmH(2)O, n = 20). Ambient temperature was maintained at 22-24℃, and anesthesia was induced and maintained with propofol-remifentanil. The core temperature and the temperature difference between forearm and fingertip skin were monitored before and after the induction of general anesthesia having a duration of 180 minutes. RESULTS: The core temperature gradient (Ti-Tf) was higher in patients with ZEEP than with PEEP. The core temperature was maintained at a higher level in patients with PEEP. Additionally, the vasoconstriction threshold was higher in patients with PEEP. CONCLUSIONS: It seems that PEEP attenuates anesthetically-induced hypothermia during TIVA.

Pneumonia due to aspiration of povidine iodine after induction of general anesthesia -A case report-.

Aspiration pneumonia is usually caused by aspiration of gastric contents during anesthesia. It causes severe pulmonary complications. Povidone iodine was used widely as an oral antiseptic. Although povidone iodine is thought to be a safe and effective antiseptic, severe complications from its aspiration may occur. We present a case of pneumonia secondary to aspiration of povidone iodine in a 16 year old female patient who underwent orofacial surgery. Aspiration pneumonia must be treated immediately. Mechanical ventilation with PEEP and periodical bronchial toilet with fiberoptic bronchoscopy were carried in the operating room and ICU. Bronchodilators, antibiotics, steroids and diuretics were also used to treat pneumonia. The patient was treated successfully without any complication.

Analysis of expert consultation referrals for anesthesia-related issues (December 2008-July 2010): KSA legislation committee report.

BACKGROUND: Since 2009, database construction of anesthesia-related adverse events has been initiated through the legislation committee of the Korean Society of Anesthesiologists (KSA), based on expert consultation referrals provided by police departments, civil courts, and criminal courts. METHODS: This study was a retrospective descriptive analysis of expert consultation referrals on surgical anesthesia-related cases between December 2008 and July 2010. RESULTS: During the given period, 46 surgical anesthesia-related cases were referred to the KSA legislation committee for expert consultation. Because six cases were excluded due to insufficient data, 40 cases were included in the final analysis. Of 40 cases, 29 (72.5%) resulted in death. Respiratory events were most common in both surviving/disabled and dead patients (36.4 vs. 51.7%, respectively; P > 0.05). Overall, respiratory depression due to the drugs used for monitored anesthesia care (MAC) was the most common specific mechanism (25%), in which all but one case (profound brain damage) resulted in death. In all of these cases, surgeons or physicians provided MAC without the help of anesthesiologists. CONCLUSIONS: Overall, the most common damaging mechanism was related to respiratory depression due to sedatives or anesthetics used for MAC. Almost all MAC injury cases are believed to be preventable with the use of additional or better monitoring and an effective response to initial physiological derangement. Thus, it is essential to establish practical MAC guidelines and adhere to these guidelines strictly to reduce the occurrence of severe anesthesia-related adverse outcomes.

Is 0.6 mg/kg of succinylcholine adequate for tracheal intubation in Korean?.

BACKGROUND: The usual dose of succinylcholine for tracheal intubation is 1.0 mg/kg. If the patient is not ventilated by face mask after administration of the succinylcholine (1.0 mg/kg), the patient may experience significant hemoglobin desaturation. The purpose of the present study was to evaluate an appropriate dose of succinylcholine for tracheal intubation in Korean. METHODS: Sixty patients scheduled for elective surgery were randomly divided into three groups; group I (succinylcholine 0.3 mg/kg, n = 20), group II (succinylcholine 0.6 mg/kg, n = 20), group III (succinylcholine 1.0 mg/kg, n = 20). All patients were not premedicated. After loss of consciousness, the patients received succinylcholine 0.3, 0.6, 1.0 mg/kg, respectively. The contraction responses of the adductor pollices muscle were monitored by using TOF. Tracheal intubation was accomplished as the height of T1 was inhibited maximally. Then, intubation scores were recorded. The recovery times from neuromuscular blockade in groups II and III were also measured. RESULTS: The acceptable conditions for tracheal intubation were 30%, 100%, and 100%, respectively in groups I, II, and III. The onset time was 80.4 +/- 15.5 sec, 69.6 +/- 13.1 sec, and 56.1 +/- 9.3 sec, respectively. The recovery time (T1 = 90%) was 446.0 +/- 86.2 sec, 694.0 +/- 84.7 sec, respectively in groups II and III. The onset time was the fastest in group III. But the recovery time in group III was slower than in group II. CONCLUSIONS: We concluded that 0.6 mg/kg of succinylcholine is an appropriate dose for tracheal intubation in Korean except for rapid sequence intubation.

The effects of intrathecal fentanyl for spinal anesthesia in lower extremity surgery.

BACKGROUND: Intrathecal opioids in combination with bupivacaine has been shown to provide adequate sensory blockade and early recovery from spinal anesthesia. This study was investigated the added effects of intrathecal fentanyl 10 microgram to bupivacaine for spinal anesthesia. METHODS: Sixty patients undergoing lower extremity surgery were into three groups. Group I received bupivacaine 10 mg (0.5%), gruop II received bupivacaine 5 mg with normal saline 1 ml, and group III received bupivacaine 5 mg with fentanyl 10 microg and normal saline 0.8 ml. RESULTS: There was no significant difference between group I and group III in the peak level and duration of sensory block. But the intensity of motor blockade was decreased in group III compared with group I and side effects of spinal anesthesia with local anesthetics was decreased in group III compared with group I. In Group II, 7 patients were complained the pain during surgery. CONCLUSIONS: Intrathecal fentanyl 10 microgram with bupivacaine 5 mg on spinal blockade provide reliable anesthesia for lower extremity surgery.

Effect of tramadol on bispectral index during anesthesia with desflurane.

BACKGROUND: This study is aimed to investigate the effect of tramadol on the bispectral index (BIS) during anesthesia with desflurane. METHODS: One hundred fifty adults, ASA class 1 and 2 patients, scheduled for general anesthesia for elective surgical procedures were included in this study. None of the patients were premedicated and anesthesia was induced with propofol 2 mg/kg and maintained with air-oxygen (FiO2 0.5) and desflurane, adjusted to keep the BIS between from 50 and 60. Forty minutes before completing surgery, the subjects were randomly allocated into 3 groups to receive saline (control group), tramadol 1.5 mg/kg (T1 group) or 3.0 mg/kg (T2 group) intravenously. Hemodynamics and BIS values were then recorded every 5 minutes until completion of the operation, during which time the concentrations of desflurane were not modified. RESULTS: The mean BIS values after tramadol administration weren't significantly different from the control group throughout the period of observation. No significant changes in the hemodynamics were noted, except systolic and diastolic arterial blood pressure in the T1 and T2 groups significantly increased in the first 5 minutes after the tramadol injection. CONCLUSIONS: The results indicate that the administration of tramadol while maintaining anesthesia with desflurane, adjusted to keep the BIS between 50 and 60, does not modified BIS values. So, we propose that tramadol can be safely administered as an immediate postoperative analgesia without concern about intra-operative awareness.

Thermoregulatory responses of sevoflurane, desflurane, and isoflurane during gynecologic laparoscopic surgery.

BACKGROUND: Core temperature decreases rapidly after the induction of general anesthesia, because the heat is redistributed to peripheral tissues. Thermoregulatory responses of volatile anesthetics have been tested, but their effects have not been directly compared. Therefore, we evaluated the thermoregulatory responses to sevoflurane, desflurane, and isoflurane. METHODS: Sixty healthy patients scheduled for laparoscopic myomectomy or radical hysterectomy were allocated into three groups; Group S (sevoflurane, n = 20), Group D (desflurane, n = 20), and Group I (isoflurane, n = 20). Anesthesia was maintained with 1 minimum alveolar concentration (MAC) of sevoflurane, desflurane, and isoflurane in a 50/50 mixture of N2O/O2. Patients were maintained in a normovolemic and normocapnic state. The core temperature and forearm minus fingertip skin-temperature gradient (an index of peripheral vasoconstriction) were monitored after the induction of general anesthesia. RESULTS: Each of the seven patients given sevoflurane, desflurane, and isoflurane vasoconstricted at a core temperature of 35.3 +/- 0.5degrees C, 33.6 +/- 0.4degrees C, and 35.2 +/- 0.4degrees C, respectively. The vasoconstriction threshold was the lowest in patients anesthetized with desflurane. The core temperature gradient (Ti-Tf) was significantly higher in patients that were anesthetized with desflurane than in those that were anesthetized with sevoflurane or isoflurane. The core temperature of desflurane was significantly lower than that of sevoflurane or isoflurane 15 minutes after the induction of anesthesia until 180 minutes of anesthesia. CONCLUSIONS: These results indicate that the core temperature is maintained at a higher level in patients that have been anesthetized with sevoflurane or isoflurane than in those that have been anesthetized with desflurane.

The effects of etomidate on the contraction of pregnant rat uterine smooth muscle.

BACKGROUND: It has been reported that etomidate has the relaxant effects on vascular, tracheal, and non-pregnant uterine smooth muscle in vitro. The purpose of this study was to investigate the relaxant effects of etomidate on the contraction of the pregnant rat uterine smooth muscle. METHODS: Uterine muscle tissues were obtained from pregnant rats (n = 15). The uterine segments were mounted in organ baths filled with Krebs solution. After oxytocin-induced contractile activity had been established, etomidate in incremental concentrations (10(-7) to 10(-3) M) was added cumulatively to the bath, each administered 20 min apart, and resultant changes in contractile activity were continuously recorded. EC5 (effective concentration of 5% reduction), EC25, EC50, EC75, and EC95 on active tension were calculated using a probit model. RESULTS: Etomidate (10(-7) to 10(-3) M) induced dose-dependent decreases in amplitude and frequency of uterine contraction. The EC50 of etomidate on active tension were 5.91 x 10(-5) M. CONCLUSIONS: These results demonstrate that etomidate had inhibitory effects on pregnant rat uterine muscle at supraclinical concentration (5.91 x 10(-5) M).

The effects of calcium channel blockers pretreatment on blood potassium level after the administration of succinylcholine in hypertensive patients.

BACKGROUND: The aim of the present study was to evaluate whether calcium channel blockers pretreatment increase blood potassium level after the administration of succinylcholine in hypertensive patients. METHODS: Eighty hypertensive patients were randomly divided into four groups: group I (saline, n = 20), group II (nicardipine 30 microg/kg, n = 20), group III (diltiazem 0.2 mg/kg, n = 20), group IV (verapamil 0.1 mg/kg, n = 20). The patients had been taking antihypertensive drugs regularly and their blood pressures were well controlled. Anesthesia was induced with thiopental sodium 5 mg/kg and tracheal intubation was facilitated with succinylcholine 1 mg/kg. Saline, nicardipine, diltiazem, and verapamil were administered two minutes before injection of succinylcholine in group I, II, III, and IV, respectively. Blood potassium level was measured prior to induction and 1, 3, 5, 10, 15, 30, 45, 60, 75, 90 minutes after administration of succinylcholine. RESULTS: Blood potassium levels at 5, 10, 15, and 30 minutes after the administration of succinylcholine were significantly increased compared with baseline values in all groups (P < 0.05). Blood potassium level was not different significantly among four groups at all times. CONCLUSIONS: Calcium channel blockers pretreatment did not increase blood potassium level after the administration of succinylcholine. We concluded that succinylcholine and calcium channel blocker can be used safely together in hypertensive patients.

Evaluation of interaction between intrathecal adenosine and MK801 or NBQX in a rat formalin pain model.

Adenosine and excitatory amino acids have been known to be involved in modulating nociceptive transmission at the spinal level. The authors assessed the characteristics of the interaction of the adenosine-excitatory amino acid antagonist combinations in the spinal cord of rats on the formalin-induced nociception. Intrathecal NMDA antagonist ((5R, 10S)-(+)-5-methyl-10,11-dihydro-(5)H-dibenzo[a[,]d]cyclohepten-5,10-imine hydrogen maleate, MK801, 30 microg) and AMPA antagonist (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[F]quinoxaline-7-sulfonamide, NBQX, 3 microg) decreased the total number of flinches during both phases in the formalin test. Intrathecal adenosine (300 microg) had little effect on the phase 1 flinching response, but decreased the phase 2 response. The fixed dose analysis and the isobolographic analysis revealed that adenosine interacts additively with MK801 and NBQX in the spinal cord.