Low-dose Propofol Research Articles

Antiemetic effect of propofol administered at the end of surgery in laparoscopic assisted vaginal hysterectomy.

BackgroundPostoperative nausea and vomiting (PONV) commonly occur after general anesthesia, especially in women. In this study, we evaluated the antiemetic efficacy of propofol administered at the end of surgery in highly susceptible patients undergoing a laparoscopy-assisted vaginal hysterectomy.MethodsA total of 107 women undergoing a laparoscopy-assisted vaginal hysterectomy under general anesthesia were enrolled for this prospective, double-blind, randomized study. Fifteen minutes before the end of surgery, all patients received 50 µg fentanyl and 1 of following 3 doses; 0.5 mg/kg of propofol (propofol 0.5 group), 1 mg/kg of propofol (propofol 1.0 group), and normal saline (control group). All patients received intravenous patient-controlled analgesia (PCA). Emergence time, a visual analog scale for pain and nausea, duration of postanesthesia care unit (PACU) stay, and frequency of antiemetic use were recorded at 0-2, 2-24, and 24-48 hours postoperatively.ResultsThe incidence of nausea significantly lower in the propofol 0.5 and propofol 1.0 groups than in the control group (12.1 vs 14.7 vs 40%). During the first postoperative 2 hours, antiemetics were less frequently administered in the propofol 0.5 and propofol 1.0 groups than in the control group (3.0 vs 5.9 vs 22.5%). Emergence time was slightly longer in the propofol 0.5 and propofol 1.0 groups than in the control group, but there was no significant difference in PACU stay time was observed between the 3 groups.ConclusionsThe results of this study suggest that low-dose propofol administration at the end of surgery may effectively reduce the incidence of PONV within 2 hours postoperatively in highly susceptible women undergoing a laparoscopiy-assisted vaginal hysterectomy and receiving opioid-based PCA.

Sedation with Combination of Midazolam, Pentazocine and Propofol for Colonoscopy in Outdoor Patients

Introduction: Diagnostic colonoscopies are generally done in OPD basis and requires sedation and analgesia to relieve both anxiety and pain. Propofol and midazolam combination is used worldwide and allows rapid and profound sedation with quick recovery. But data on combined sedation with midazolam, pentazocine and propofol are not found. So this study was conducted to test this combination for day care surgery. Methods: Prospectively, 242 colonoscopy procedures who had received combined sedation with midazolam, pentazocine and propofol were analysed. Midazolam and Pentazocine were given intravenously as a single dose of 2 mg and 15 mg respectively. 20 mg of Propofol was given bolus, than 10 mg top up titrating sedation till procedure is finished. Pulse, Non Invasive Blood pressure and oxygen saturation were recorded. Patients' genders, ages, weight, length of procedure and the need of total received Propofol for complete sedation in mg were recorded. Movement during procedure, the time of recovery and any complications were also recorded. Patients were also asked whether they had any memories of procedure. Results: Lower dose of propofol is required to produce adequate aesthesia. There are no complication and vitals were stable including oxygen Saturation. There was quicker recovery as all patients responds on verbal command just after the procedure and no patient had memories of the procedure. All patients safely discharged within one hour. Conclusions: The combination is safe and comfortable for patients undergoing diagnostic colonoscopy to produce adequate anaesthesia without any significant complications.Medical Journal of Shree Birendra Hospital; July-December 2012/vol.11/Issue2/7-9 DOI: http://dx.doi.org/10.3126/mjsbh.v11i2.7900

Comparison of propofol-based sedation regimens administered during colonoscopy.

The ideal sedative agent for endoscopic procedures should allow a rapid modification of the sedation level and should not have any adverse effects. To evaluate and compare the efficacy, safety, cost and patient satisfaction of some propofol-based sedation regimens administered during colonoscopy. One hundred twenty one patients scheduled for elective outpatient colonoscopy with conscious sedation were randomized to four groups to evaluate the administration of dexmedetomidine, sufentanil, meperidine and midazolam in combination with propofol to maintain sedation during the procedure. Evaluated outcomes were efficacy, safety, cost and patient satisfaction of sedation procedures. Patients receiving dexmedetomidine achieved a higher degree of sedation when compared with the other groups (p < 0.05). The lapse to recover protective reflexes and motor function, was significantly shorter in groups receiving dexmedetomidine or sufentanil than in groups receiving meperidine or midazolam (p < 0.05). There were no differences between groups in pre-sedation and post-sedation neurophysiologic performance, measured by the Trail Making A and B tests. Sedation for endoscopy can be safely and effectively accomplished with low doses of propofol combined with dexmedetomidine, intranasal sufentanil, IV meperidine and IV meperidine with midazolam.

High-Dose Propofol Reduces S-100β Protein and Neuron-Specific Enolase Levels in Patients Undergoing Cardiac Surgery

In a variety of experimental models, propofol has been shown to protect the brain. It was hypothesized that a clinically achievable high dose of propofol would induce cerebral protective effects in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). The authors investigated the effects of different target plasma concentrations of propofol on cerebral injury by measuring serum S-100β protein and neuron-specific enolase (NSE) levels in patients undergoing single-valve replacement with CPB. A prospective, randomized study. A university hospital. Forty-two patients undergoing single-valve replacement with CPB. Patients were randomly divided into 3 groups (n = 14 each). Each group received a target-controlled infusion of propofol with plasma concentrations of 1.8 μg/mL (low dose, Group-L), 2.4 μg/mL (medium dose, Group-M), or 3.2 μg/mL (high dose, Group-H). The propofol target concentrations were unchanged throughout the surgery. In all 3 groups of patients, at all time points after CPB, the plasma S-100β protein and NSE levels, which served as biochemical markers of brain damage, were significantly higher than the preoperative levels (p<0.05). Group-H showed significant decreases in S-100β protein and NSE compared with Group-L (p< 0.05). In the range of commonly used clinical concentrations, administration of a high dose of propofol during CPB attenuated the biochemical markers of brain damage as compared with low-dose propofol anesthesia.

Attenuation of Cardiovascular Responses and Upper Airway Events to Tracheal Extubation by Low Dose Propofol

BackgroundHemodynamic changes and respiratory tract complications are often followed by tracheal extubation. These events may be dangerous in neurosurgical patients and those with cardiovascular disease or at an old age.ObjectivesThe aim of this study is to investigate the attenuation of cardiovascular responses and upper airway events resulting from tracheal extubation by low dose propofol.Materials and Methods80 patients with ASA physical status I, undergoing an elective surgery in a double blind manner received 0.5mg/kg propofol or normal saline 2 minutes before extubation. Heart rate and blood pressure and quality of tracheal extubation were recorded.ResultsHeart rate and blood pressure in patients receiving propofol were less than the control group (P < 0.05) at the time of injection of propofol, but there were no differences between the two groups at the time of extubation.ConclusionsWe concluded that propofol can reduce SBP, DBP, MAP, HR & cough production at the time of injection but there were no significant changes in these parameters after extubation.

The combined effects of midazolam and propofol sedation on muscle power

We performed a randomised, crossover study to investigate the effects of intravenous sedation on grip strength and bite force. Twenty male volunteers received a bolus intravenous injection of midazolam (0.02 mg.kg(-1)) together with a 30-min propofol infusion designed to achieve an effect-site concentration of 1.0 μg.ml(-1). Observed variables included bispectral index, observer's assessment of alertness/sedation, correct answer rate of Stroop colour-word test, grip strength and bite force. Grip strength decreased from a median (IQR [range]) of 483 (443-517 [380-586]) N to 358 (280-405 [108-580]) N (p < 0.001) during sedation and recovered following flumazenil administration, while bite force increased from 818 (593-1026 [405-1406]) N to 1377 (1243-1585 [836-2357]) N (p < 0.001) during sedation. Although bite force gradually returned to baseline following flumazenil administration, it remained increased throughout the experimental period. We conclude that bite force increased during intravenous sedation and that this may have clinical implications.

Effects of propofol on airway hyperresponsiveness and airway inflammation of asthmatic mice

Objective To investigate the immunoregulatory effects of propofol on airway hyperresponsiveness,airway inflammation and Thl/Th2 ratio in the asthmatic mice.Methods One hundred female BALB/c mice,aged 6-8 weeks,weighing 18-20 g,were randomly divided into 5 groups (n =20,each):control group (normal saline i.p.,group C),asthma group (group A),low-dose propofol (50 mg/kg i.p.,group LP),medium-dose propofol (100 mg/kg i.p.,group MP) and high-dose propofol (150 mg/kg i.p.,group HP).Mice of groups A,LP,MP and HP were sensitized with ovalbumin (OVA),mice of group C were sensitized with normal saline.24 h after the last challenge,animals were sacrificed by lethal dose of pentobarbital sodium.Blood and bronchoalveolar lavage fluid (BALF) were collected for determination of serum OVA-specific IgE and the levels of cytokines (IL-4,IL-5 and IFN-γ) in the BALF.Airway responsiveness was measured by the forced-oscillation technique and histological inflammation scores were measured by staining with hematoxylin and eosin.Results Propofol (group LP and group MP) attenuated airway hyperresposiveness to the muscarinic agonist methacholine in OVA-induced asthma.Different doses of propofol (group LP,group MP and group HP) decreased eosinoplils influx in lungs.In addition,propofol treatment reduced expression of IL-4,IL-5 and serum OVA-specific IgE and increased the ratio of IFN-γ/IL-4.Conclusion The study demonstrates a potential protective value of propofol in alleviating airway inflammation,up-regulating Th1/Th2 ratio and attenuating airway hyperresposiveness in the asthmatic mice. Key words: Asthma; Propofol ; Respiratory hypersensitivity ; Inflammation

Medial septal lesion enhances general anesthesia response

Electrolytic lesion of the medial septum, a basal forebrain nucleus that projects to the hippocampus, prolonged the emergence from general anesthesia in rats. Septal lesioned rats required a longer time to recover from a loss of righting reflex (LORR) and a loss of tail-pinch response after injectable (20mg/kg i.p. pentobarbital, 5mg/kg i.v. propofol) or volatile (1.5% halothane, 2% isoflurane) anesthetic. When incremental doses of propofol were given i.p., septal lesioned rats as compared to control rats showed LORR at a lower dose of propofol. Similarly, when the rats were exposed to increasing concentrations of isoflurane, the percent of rats showing LORR was leftward shifted for lesioned rats as compared to control rats. Septal lesioned rats as compared to control rats showed decreased locomotor activity when exposed to 1.5% halothane. Lesion of the medial septum was confirmed by thionin-stained histological sections as well as loss of acetylcholinesterase (AchE) staining in the hippocampus, indicating a depletion of septohippocampal cholinergic afferents. Medial septal lesion resulted in a near complete loss of hippocampal theta rhythm during walking and a general decrease in power of the hippocampal EEG at all frequencies (0–100Hz), during walking or immobility. It is concluded that lesion of medial septum, in part through a loss of septohippocampal cholinergic afferents, increased the anesthesia response to volatile and injectable general anesthetics, during both induction and emergence. It is suggested that the septohippocampal system participates in many components of general anesthesia including hypnosis, immobility, and analgesia.

Low Dose Propofol with Dexmedetomidine is Effective for Monitored Anesthesia Care in Outpatients Undergoing Invasive Oral Surgery

Low Dose Propofol with Dexmedetomidine is Effective for Monitored Anesthesia Care in Outpatients Undergoing Invasive Oral Surgery

Hemiarthroplasty performed under transversus abdominis plane block in a patient with severe cardiorespiratory disease

This report describes the use of a transversus abdominis plane block as the main anaesthetic technique for the performance of a hemiarthroplasty in a patient with severe cardiac and respiratory dysfunction, for whom both general and spinal anaesthesia carried considerable risks. The block was performed in the triangle of Petit posterior to the mid-axillary line, using a landmark technique. A combination of lidocaine 1% (20 ml) and bupivacaine 0.5% (20 ml) was administered. A low-dose propofol infusion was used intra-operatively to relieve anxiety, although the patient breathed spontaneously throughout the procedure and responded to voice commands. The surgery was completed successfully without the need for further analgesia. The patient was alert and comfortable in recovery. First opioid administration was 12 h after surgery. The patient was subsequently discharged to a nursing home, where he succumbed to his primary respiratory disease six months later.

Effects of low-dose fentanyl combined with propofol in painless gastroscopy

Objective To investigate the efficacy and clinical values of low-dose fentanyl combined with propofol in painless gastroscopy.Methods 122 patients undergoing painless gastroscopy were randomly divided into study group (65 patients) and control group (57 patients).The study group received anesthesia with low-dose fentanyl plus propofol,while the control group received anesthesia with propofol alone.The anesthetic effects and adverse reactions were observed in both groups.Results Time to sleepiness and time to awakening were significantly shorter in the study group than in the control group (P＜ 0.05).The scores on the DSST was significantly greater in the study group than in the control group (P＜ 0.05).The incidence rates of respiratory depression and local pain due to injection were significantly lower in the study group than in the control group (P ＜ 0.05).Conclusions Small-dose fentanyl combined with propofol is safe and effective in painless gastroscopy. Key words: Gastroscopy; Fentanyl; Propofol

Low-Dose Propofol for the Abortive Treatment of Pediatric Migraine in the Emergency Department

Limited progress has been made in the past decade for abortive treatment of migraine headache in the pediatric emergency department (PED). Propofol, a general anesthetic, has been reported to be effective in the treatment of refractory headaches in adults at subanesthetic doses but never in the pediatric population. The goal of this study was to review our institution's experience with subanesthetic doses of propofol for the abortive treatment of pediatric migraine and compare propofol with standard abortive therapy in the PED. Retrospective review of all patients discharged from the Oregon Health and Science University PED with a diagnosis of migraine headache from January 2010 to July 2011. Patients treated with subanesthetic doses of propofol were compared with matched controls who received standard abortive migraine therapy, defined as the combined use of a nonsteroidal anti-inflammatory medication, diphenhydramine, and prochlorperazine. Outcome variables of interest included reduction of pain as measured on a self-reported visual analog scale and length of stay after administration of initial abortive medication. Patients who received subanesthetic doses of propofol achieved significantly greater reduction in pain scores (80.1% vs 61.1%; P < 0.05) compared with matched controls as well as shorter stay (122 minutes vs 203 minutes; P = 0.2) after treatment. No adverse effects (hypotension, respiratory depression, or hypoxia) were recorded in either group. Propofol seems to be effective for the abortive treatment of pediatric migraine headache in the PED. Further prospective trials are warranted to either support or refute these initial findings.

Safety and Effectiveness of Low-Dose Propofol Sedation During and After Esophagogastroduodenoscopy in Child A and B Cirrhotic Patients

Effective and safe sedation for patients with liver cirrhosis is problematic. To examine the safety and effectiveness of low-dose propofol sedation during and after esophagogastroduodenoscopy (EGD) in cirrhotic patients. Study 1 was a prospective study in cirrhotic patients who underwent diagnostic EGD under propofol sedation. Propofol was given by bolus injection with an age-adjusted standard protocol consisting of 40 mg for patients <70 years, 30 mg for patients aged 70-89 years; additional injections of 20 mg propofol were given up to a maximum of 120 mg. The principal parameter was the occurrence of adverse events within 24 h after EGD. Secondary parameters included successful procedures, complications, and full recovery within 60 min. In Study 2, the residual effects of propofol were evaluated using a driving simulator and blood propofol concentrations in a subset of cirrhotic patients undergoing EGD and compared with healthy individuals. The principal parameter was driving ability. Study 1: Consecutive cirrhotic patients were entered and all 163 successfully completed EGD. The mean dose of propofol was 46 mg (range 30-120 mg). No complications occurred. Full recovery had occurred in 100 % 60 min after the procedure. No adverse events occurred within 24 h after EGD. Study 2: There were no significant differences in blood propofol levels between cirrhotic patients (n = 21) and healthy individuals (n = 20) after sedation. In cirrhotic patients, there was no deterioration in driving ability as compared with healthy individuals. Low-dose propofol sedation provided safe and effective sedation for EGD in cirrhotic patients with rapid recovery.

Journal-related Activities and Other Special Activities at the 2012 American Society of Anesthesiologists Annual Meeting

Journal-related Activities and Other Special Activities at the 2012 American Society of Anesthesiologists Annual Meeting

Hemodynamic stability in an optimized propofol-remifentanil based anesthesia for ophthalmic surgery

Background and Goal of the Study: A deep level of anesthesia is often required in ophthalmic surgery to obtain optimal surgical conditions, which may induce significant cardiovascular impairment and compromise tissue oxygenation. We investigated the hemodynamic stability and tissue oxygenation in a balanced general anesthesia with remifentanil, low-dose propofol, norepinephrine and goal-directed fluid administration in patients undergoing ophthalmic surgery. Material and Methods: 40 consecutive patients were included after informed consent was obtained. Anesthesia was induced with 1-3 mg kg-1 propofol, 1 µg kg-1 remifentanil, 0.1 mg kg-1 cisatracurium and an additional bolus of norepinephrine 10 µg, if required. Anesthesia was maintained with 4 mg kg-1 min-1 propofol, 0.25 µg kg-1 min-1 remifentanil and 0.05 µg kg-1 min-1 norepinephrine if required and further titrated to a MAP above 80% of baseline. Propofol or remifentanil infusion was increased upon the discretion of the anesthetist and targeted to a BIS value between 40 - 60. Voluven® 500ml was administered if the plethysmographic wave variation was > 10%. Tissue oxygen saturation (StO2) was measured by near-infrared spectroscopy using the Inspectra device (Model 650, Hutchinson Technology, USA) at the left thenar eminescence. Hemodynamics (cardiac index (CI), mean arterial pressure (MAP) and heart rate (HR)) were measured non-invasively (Nexfin, BMEye, Amsterdam). Results and Discussion: Mean (SD) StO2 increased from 83 (6) % before induction to 86 (4) % 20 minutes after induction of anesthesia (p< 0.05) and remained stable throughout the procedure. Cardiac index dropped from 3.0 (0.7) to 2.1 (0.4) L min-1 after 20 minutes (p< 0.05). Furthermore MAP decreased from 109 (16) to 83 (14) mm Hg and HR from 73 (12) to 54 (8) bpm (both p< 0.05). 14/40 patients received a 500 ml Voluven bolus. The median (range) norepinephrine administration rate was 0.05 (0.0 - 0.10) µg kg-1 min-1. The overall median (IQR) BIS value from induction of anesthesia to the end of the procedure was stable in all patients and was 44 (40 - 51), while 3/40 patients required additional propofol or remifentanil. Conclusion: This balanced protocol based on remifentanil, low-dose propofol, norepinephrine and goal-directed fluid therapy preserves StO2 while other hemodynamic variables are within a clinically acceptable range, suggesting this protocol to be feasible for use in anesthesia for ophthalmic surgery.

Incidence of Propofol Injection Pain and Effect of Lidocaine Pretreatment During Upper Gastrointestinal Endoscopy

To the Editor, We read with great interest the article by Kwon et al., in which the authors concluded that pretreatment with 1 % lidocaine 20 mg was effective in preventing propofol pain compared with placebo during upper gastrointestinal endoscopy [1]. We all agree with the idea that propofol pain is currently a common problem, not only in general anesthesia but also in nonoperation room anesthesia which is applied with sedation for various procedures. Therefore it is important to prevent propofol pain, and many techniques and drugs are used for its prevention as the authors specified in the article. Additionally, we think that it is important here to determine the other issues with propofol pain which are not emphasized in the publication and may affect the results. It has been shown that the propofol formulation is also an impressive factor in propofol pain. The concentration of free propofol in the aqueous phase is known to be associated with the intensity of pain on injection [2]. Although the LCT and LCT/MCT formulas of propofol have equal effect, the amount of free propofol which is believed to be responsible for injection pain is much more in the propofol LCT formulation when compared with the MCT/LCT formulation [3, 4]. Besides, according to our experience [5] and the studies on propofol pain, it is suggested that to reduce the pain elicited by the iv injection of propofol, the most common medication is to give lidocaine in a variety of rates, doses and concentrations [6]; especially pretreatment with iv 0.5 mg/ kg lidocaine is the optimal method for reducing pain caused by propofol [5]. Therefore, we suggest that the emulsion with MCT/LCT formulation of propofol with the pretreatment of 0.5 mg/kg lidocaine or premixing propofol with 20 mg lidocaine to reduce the concentration of free propofol in the aqueous phase of the emulsion may be more effective in preventing propofol pain during upper endoscopy. Further studies are needed to corroborate our suggestions in preventing pain of low dose propofol in sedation for different endoscopic procedures.

Heart Rate Variability Dynamics During Low-Dose Propofol and Dexmedetomidine Anesthesia

Heart rate variability (HRV) has been observed to decrease during anesthesia, but changes in HRV during loss and recovery of consciousness have not been studied in detail. In this study, HRV dynamics during low-dose propofol (N = 10) and dexmedetomidine (N = 9) anesthesia were estimated by using time-varying methods. Standard time-domain and frequency-domain measures of HRV were included in the analysis. Frequency-domain parameters like low frequency (LF) and high frequency (HF) component powers were extracted from time-varying spectrum estimates obtained with a Kalman smoother algorithm. The Kalman smoother is a parametric spectrum estimation approach based on time-varying autoregressive (AR) modeling. Prior to loss of consciousness, an increase in HF component power indicating increase in vagal control of heart rate (HR) was observed for both anesthetics. The relative increase of vagal control over sympathetic control of HR was overall larger for dexmedetomidine which is in line with the known sympatholytic effect of this anesthetic. Even though the inter-individual variability in the HRV parameters was substantial, the results suggest the usefulness of HRV analysis in monitoring dexmedetomidine anesthesia.

A47 Does Morphine prolong Emergence in Neurosurgical Patients

Background and Goal of Study: One of the major concerns in neurosurgical patients is emergence. The idea is to allow early neurological examination and reintervention if necessary. More than two decades of quest for an ideal anaesthetic agents to fast track recovery has not yielded conclusive results. Long acting opoids like morphine are not popular for use in neurosurgical patients and the acceptability is for short acting opioids. However there is paucity of data which compares morphine and short acting opioids with regards to their emergence profile in neurosurgical patients. This study was done to evaluate the emergence characteristics of morphine when compared to fentany in patients undergoing elective neurosurgery. Methods: The data of two major tertiary health care institutes of India were compared . One institute predominantly uses morphine while the other uses fentanyl for perioperative analgesia in patients undergoing neurosurgery. The patients who underwent elective supratentorial craniotomy and followed similar emergence technique (low dose propofol along with nitrous oxide in oxygen) were included in the study. The dose of opioids were based on the protocol of individual institution. The patients of morphine group (Group M) received single dose morphine 0.1mg/kg prior to induction. The fentany group (Group F) received 2 ug/kg of fentanyl at induction, 1ug/kg prior to skin incision and at beginning of dural closure. In both groups Fentanyl 1ug/kg was given as additional dose if required. Following surgery, the trachea was extubated after reversal of residual neuromuscular blockade once the patients opened eyes or responded to verbal commands. The emergence chararacteristic among the two groups were compared. Results: A total of eighty four patients qualified for inclusion in the study. There were thirty-seven patients in Group M while Group F had forty-seven patients. The mean time to emergence (time from cessation of anaesthesia to extubation) was 8.5 ± 3.7 minutes in group M and 7.8 ± 5.1 minutes in group F ( p = 0.11). The patients who had early emergence (< 15 minutes following cessation of anaesthesia) were 35 (94%) in group M while it were 43(91%) in group F (p= 0.69). Conclusion: When used judiciously, morphine appears acceptable and similar to fentany for facilitating early emergence in patients undergoing elective supratentorial craniotomy.

Pharmacokinetics of ketamine and propofol combination administered as ketofol via continuous infusion in cats

The pharmacokinetics of the extemporaneous combination of low doses of ketamine and propofol, known as 'ketofol', frequently used for emergency procedures in humans to achieve safe sedation and analgesia was studied in cats. The study was performed to assess propofol, ketamine and norketamine kinetics in six female cats that received ketamine and propofol (1:1 ratio) as a loading dose (2 mg/kg each, IV) followed by a continuous infusion (10 mg/kg/h each, IV, 25 min of length). Blood samples were collected during the infusion period and up to 24 h afterwards. Drug quantification was achieved by HPLC analysis using UV-visible detection for ketamine and fluorimetric detection for propofol. The pharmacokinetic parameters were deduced by a two-compartment bolus plus infusion model for propofol and ketamine and a monocompartmental model for norketamine. Additional data were derived by a noncompartmental analysis. Propofol and ketamine were quantifiable in most animals until 24 and 8 h after the end of infusion, respectively. Propofol showed a long elimination half-life (t(1/2λ2) 7.55 ± 9.86 h), whereas ketamine was characterized by shorter half-life (t(1/2λ2) 4 ± 3.4 h) owing to its rapid biotransformation into norketamine. The clinical significance of propofol's long elimination half-life and low clearance is negligible when the drug is administered as short-term and low-dosage infusion. The concurrent administration of ketamine and propofol in cats did not produce adverse effects although it was not possible to exclude interference in the metabolism.

Effect of isolated carotid sinus perfusion with propofol on plasma endothelin and nitric oxide levels in diabefic rats

Objective To investigate the effect of isolated carotid sinus perfusion with propofol on plasma endothelin and nitric oxide levels in diabetic rats.Methods Healthy adult Wistar rats weighing 180-220 g were used in this study.Diabetes mellitus was induced by intraperitoneal streptozotocin 30 mg/kg and confirmed by blood glucose ≥ 16.7 mmol/L.Thirty-six rats in which diabetes mellitus model was successfully established were randomly divided into 3 groups ( n =12):control group (group DC) ;low dose propofol group (group DP1 ) and high dose propofol group (group DP2 ).Another 36 non-diabetic rats were also randomly divided into 3 group ( n =12 each):control group (group NC) ; low dose propofol group group (group NP1 ) and high dose propofol (group NP2 ).After 30 min isolated carotic sinus perfusion with K-H solution (control groups),50 μmol/L propofol in K-H solution (low dose propofol groups) or 100 μmol/L propofol in K-H solution (high dose propofol groups),blood samples were taken for determination of plasma endothelin and nitric oxide concentrations.Results The plasma endothelin concentration was lower and nitric oxide concentration higher in groups DP1 and DP2 than in group DC,and in group DP1 than in group DP2 ( P ＜ 0.05).The plasma endothelin concentration was higher and nitric oxide concentration lower in group NPi than in group DP1,and in group NP2 than in group DP2 ( P ＜ 0.05 ).Conclusion Propofol can decrease endothelin level and increase nitric oxide level in diabetic or non-diabetic rats through local effect on carotid sinus,and the effect is stronger in diabetic rats than in non-diabetic rats. Key words: Propofol; Diabetes mellitus; Edothelins; Nitric oxide; Carotid sinus