Hypnotic Dose Of Propofol Research Articles

In vivo imaging reveals a synchronized correlation among neurotransmitter dynamics during propofol and sevoflurane anesthesia.

General anesthesia is widely applied in clinical practice. However, the precise mechanism of loss of consciousness induced by general anesthetics remains unknown. Here, we measured the dynamics of five neurotransmitters, including γ-aminobutyric acid, glutamate, norepinephrine, acetylcholine, and dopamine, in the medial prefrontal cortex and primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from a neurotransmitter perspective. Results revealed that the concentrations of γ-aminobutyric acid, glutamate, norepinephrine, and acetylcholine increased in the cortex during propofol-induced loss of consciousness. Dopamine levels did not change following the hypnotic dose of propofol but increased significantly following surgical doses of propofol anesthesia. Notably, the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness. Furthermore, the neurotransmitter dynamic networks were not synchronized in the non-anesthesia groups but were highly synchronized in the anesthetic groups. These findings suggest that neurotransmitter dynamic network synchronization may cause anesthetic-induced loss of consciousness.

Efficacy of sub - hypnotic dose of propofol or dexamethasone for attenuation of intrathecal morphin - induced post - operative nausea and vomiting in parturient under cesarean section - a randomized control trial

ABSTRACT Background: Preventing nausea and vomiting in women undergoing post cesarean section played an important role in improving quality of care, enhanced patient satisfaction in breastfeeding and caring for the newborns.This study aimed to determine the incidence of postoperative nausea and vomiting among parturients receiving sub-hypnotic dose of propofol or dexamethasone as prophylaxis after cesarean section under intrathecal morphine to extend post-operative analgesia and the side effects of these drugs on patients. Methods: The study was conducted on 180 pregnant women with written informed consent.All pregnant women under spinal anesthesia were supplemented with intrathecal morphine for postoperative extended analgesia andeach recruited parturient was assigned to one of 3 groups using random allocation software. 60 parturients in each group were allocated to 0.5 mg/kg of propofol or 8 mg of dexamethasone (for post - operative nausea and vomiting prophylaxis) and NaCl 0.9% for the control group. Postoperative nausea and vomiting (PONV) incidence, heart rate, blood pressure, SpO2, respiratory rate, Richmond Agitation Sedation Scale (RASS) score and side effects of propofol and dexamethasone were recorded. Results: It was noted that the incidence of post-operative nauseasignificantly decreased in the propofol group (18,3%) or the dexamethasone group (20%) compared with the control group (51,7%) (P < 0.05).Similarly, post-operative vomiting was significantly reduced in the propofol group (6,7 %) or the dexamethasone group (8,3 %) compared with the control group (21,7%) (P < 0.05).There were no changes among parturients from the control group, propofol group, and the dexamethasone group regarding heart rate, blood pressure, SpO2, respiratory rate and RASS score. 11(18,3%) from the propofol group experienced pain. There were no side - effects related to dexamethasone. Conclusion: This study’s findings suggested that a sub- hypnotic dose of propofol could be as effective as dexamethasone in preventing PONV in parturient undergoing cesarean section under spinal anesthesia with intrathecal morphine to extend post-operative analgesia. There were no effects on vital signs, except for pain on propofol injection.

Effect of sub-hypnotic dose of propofol on prevention of postoperative nausea and vomiting as part of multimodal antiemetic in patients undergoing open abdominal surgery: A prospective cohort study, Gondar University Hospital, Northwest Ethiopia, 2016

BackgroundPostoperative nausea and vomiting (PONV) is one of the most common and unpleasant symptoms affecting patients undergoing abdominal surgery under general anaesthesia. It is also associated with complications such as gastric aspiration, bleeding, dehydration, wound dehiscence and delayed hospital discharge. ObjectiveThe aim of this study was to assess the effect of a sub hypnotic dose of propofol on the occurrence and severity of PONV after open abdominal surgery under general anaesthesia. Materials and methodsA series of 72 adult (age ≥18) ASA class I or II patients, scheduled for open abdominal surgery were divided into a control group (n = 36) and a propofol group (n = 36). The propofol group was given 30 mg of 1% propofol IV bolus after skin closure. All episodes and severity of PONV during the first 24 h after anaesthesia were evaluated. ResultsThe overall incidence of PONV was significantly lower in propofol group than the non-propofol group during the first six postoperative hours (30.6% versus 66.7% respectively; p = 0.002). There was a significant reduction in number of patients needing rescue anti-emetic during the first six postoperative hours in propofol group when compared with none-propofol group [5 (13.9%) and 15 (41.7%) respectively, (p = 0.009)]. There were no significant differences between the groups with regard to their haemodynamic parameters and manifestations of respiratory depression. Conclusion and recommendationAdministration of a sub hypnotic intravenous dose of propofol was effective in reducing the incidence and severity of PONV, and the need for rescue anti-emetic during the first six postoperative hours in patients undergoing open abdominal surgery under general anaesthesia. We recommend the use of 30 mg propofol at the end of open abdominal surgery as part of multimodal approach for PONV.

Prevention of postoperative nausea and vomiting with a subhypnotic dose of Propofol in patients undergoing lower abdominal surgery: A prospective, randomized, double-blind study.

Background:Postoperative nausea and vomiting (PONV) is a common complication after general anesthesia in patients undergoing elective lower abdominal surgery. We aimed to compare the effect of a sub hypnotic dose of Propofol in the prevention of PONV after lower abdominal surgery with that of the conventional antiemetic drug Metoclopramide.Materials and Methods:In this prospective, randomized, double-blind, placebo-controlled study, 104 patients with American Society of Anesthesiologists (ASA) class I or II status, aged 18–65 years, and undergoing elective lower abdominal surgery were randomized to one of four groups (n = 26 each). The patients in the four groups were administered intravenously Propofol 20 mg (G1), Propofol 30 mg (G2), Metoclopramide 10 mg (G3), and placebo (G4), 15 min before skin closure. All episodes of PONV during the first 24 h after anesthesia were recorded by an investigator who was blinded to treatment assignment.Results:There were no significant differences between the treatment groups with regard to their gender, age, ASA class, duration of surgery, duration of recovery time and hospital stay, and also body mass index (BMI) (P > 0.05). The prevalence of PONV 0-6 h after anesthesia was 23.08% with Propofol 20 mg (P = 0.005), 15.38% with Propofol 30 mg (P = 0.016), 15.38% with Metoclopramide 10 mg (P = 0.016), compared to 30.77% with placebo (P = 0.005).Conclusions:Administration of a subhypnotic dose of Propofol (30 mg) was found to be as effective as 10 mg Metoclopramide in reducing the incidence and severity of PONV in adult patients undergoing elective lower abdominal surgeries under Isoflurane-based anesthesia in the early postoperative period.

Prevention of postoperative nausea and vomiting by administration of sub hypnotic doses of propofol and midazolam during spinal anesthesia for Cesarean section

Tehran University of Medical Sciences (TUMS), Mirza Koochak Khan Hospital, Department of Anaesthesiology, Tehran, Iran, Islamic Republic of

Dexmedetomidine and hydroxyzine synergistically potentiate the hypnotic activity of propofol in mice

Investigation into the characteristics of anesthetic interactions may provide clues to anesthesia mechanisms. Dexmedetomidine, an α(2)-adrenergic receptor agonist, has become a popular sedative in intensive care, and hydroxyzine, a histamine receptor antagonist, is well known as a tranquilizing premedication for anesthesia. However, no experimental or pharmacological evaluation has been reported concerning their combination with propofol. Thus, we studied their combined effect with a hypnotic dose of propofol in ddY mice. Male adult mice were intravenously administered either dexmedetomidine (30μg/kg) or hydroxyzine (5mg/kg) with propofol (3.75-10mg/kg) to induce hypnosis, defined as a loss of the righting reflex (LRR). Other mice were intravenously administered propofol, dexmedetomidine (300μg/kg), or hydroxyzine (50mg/kg) alone, and subsequent behavioral changes were observed. The 50% effective dose (ED(50)) for LRR was calculated, and the duration of LRR was determined. The hypnotic dose of propofol was 9.95±1.04mg/kg (ED(50)±SEM) without combination. Dexmedetomidine and hydroxyzine reduced the ED(50) of propofol to 5.32±0.57 and 5.63±0.57mg/kg, respectively. Coadministration of dexmedetomidine significantly extended LRR duration compared with propofol alone, whereas hydroxyzine significantly shortened LRR duration. A maximal dose of dexmedetomidine or hydroxyzine alone did not induce hypnosis. Dexmedetomidine and hydroxyzine demonstrated no hypnotic action alone; however, their coadministration potentiated the hypnotic activity of propofol. Although reduction in the dose of propofol was similar, only dexmedetomidine prolonged the duration of hypnosis.

Effect of divided supplementation of remifentanil on seizure duration and hemodynamic responses during electroconvulsive therapy under propofol anesthesia

Although a reduced dose of propofol combined with remifentanil is often used in anesthesia for electroconvulsive therapy (ECT), there have been few studies in which the optimal technique for injection of remifentanil was examined in detail. The aim of this study was to evaluate the effects of single and divided injection of remifentanil combined with propofol on seizure duration and hemodynamic responses during ECT. Twenty-six ASA I-II patients were enrolled in this study and received a total of 78 ECTs. Each patient received propofol 1.2mg/kg (group P), remifentanil 1μg/kg followed by propofol 0.5mg/kg (group R1), and remifentanil 1μg/kg followed by propofol 0.5mg/kg and thereafter remifentanil 2μg/kg (group R2). Succinylcholine 1mg/kg was used for muscle paralysis after loss of consciousness. Although mean motor seizure durations were significantly longer in groups R1 and R2 than in group P (P<0.05), they were similar in groups R1 and R2. Although the percentage increases in mean arterial pressure after ECT were significantly smaller in groups P (P<0.01) and R2 (P<0.05) than in group R1, they did not significantly differ between groups P and R2. Divided use of remifentanil at 1 and 2μg/kg combined with propofol 0.5mg/kg produces an acceptable outcome in both seizure duration and hemodynamic stability during ECT compared with the standard hypnotic doses of propofol alone or remifentanil 1μg/kg followed by propofol 0.5mg/kg.

Subhypnotic doses of propofol accelerate extinction of conditioned taste aversion

Subhypnotic doses of propofol accelerate extinction of conditioned taste aversion. Some intravenous anesthetic agents including propofol is known to induce anterograde and retrograde amnesia. We evaluated whether propofol affect the long-term memory formed by the conditioned taste aversion (CTA) paradigm. Rats were allowed a 4 h access to water through the experiments. After preconditioning water intake, the rats were offered 0.1% sodium saccharin (Sac) as conditioned stimulus (CS) for 20 min. An intraperitoneal (i.p.) injection of several concentrations (0.5–100 mg/kg) of propofol 10 min after Sac exposure was followed by an i.p. injection of 0.15 M LiCl (2% of body weight) as unconditioned stimulus (US) 30 min after CS-exposure. The volumes of intake of Sac for 20 min were measured on the successive 4 days. The rats, which acquired CTA by every CS–US paradigm, strongly avoided Sac on the first test day after conditioning and maintained the avoidance for 3 days. However, when subhypnotic dose of propofol was injected before LiCl-injection, Sac intake abruptly increased on the second test day and the almost complete extinction occurred on the third test day after conditioning. The extinction process of CTA was barely affected by hypnotic dose of propofol. These results suggest that propofol affects the retention mechanism of the CTA memory in a dose-dependent manner. Subhypnotic dose of propofol may affect the sub-cellular process of the memory consolidation in CTA.

Flumazenil reduces the hypnotic dose of propofol in male patients under spinal anesthesia

Flumazenil has been reported to produce a partial benzodiazepine-agonist-like effect in some psychopharmacological examinations. This study investigated the effect of flumazenil on the hypnotic activity of propofol in 60 men scheduled for minor surgical procedures done under spinal anesthesia. After a steady state of spinal anesthesia had been reached, patients were pretreated with saline or flumazenil, 5 microg.kg(-1), followed by the administration of saline or midazolam, 10 microg.kg(-1). Then, 250 microg.kg(-1).min(-1) of propofol was infused until hypnosis was achieved. Loss of response to a simple command with a slight stimulus, served as the end-point for hypnosis. Immediately after achievement of the end-point, propofol infusion was discontinued, and a 2-ml venous blood sample was obtained from the dorsal pedis vein to determine plasma propofol concentration. Flumazenil significantly decreased the dose of propofol required and the time required to achieve hypnosis compared with values in the control group (55 +/- 10 [mean +/- SD] vs 71 +/- 14 mg and 212 +/- 42 vs 268 +/- 48 s, respectively; P < 0.05), whereas flumazenil attenuated the effect of midazolam in reducing the plasma concentration of propofol at hypnosis (2.9 +/- 0.5 and 2.5 +/- 0.6 microg.ml(-1), respectively; P < 0.05). These results suggested that flumazenil may potentiate the hypnotic properties of propofol, despite flumazenil having an antagonistic effect on the enhanced hypnotic activity of propofol induced by the coadministration of midazolam.

The determinants of propofol induction of anesthesia dose.

Recently it was reported that the pharmacokinetics of propofol are modified by changes in cardiac output. The objective of this study was to evaluate the effects of cardiac output and other factors on the hypnotic dose of propofol. One-hundred surgical patients were administered indocyanine green immediately before the induction of anesthesia to measure their cardiac outputs and blood volumes. Propofol (250 microg. kg(-1). min(-1)) was infused IV for 8 min, and the hypnotic dose of propofol and the time to hypnosis were recorded. The plasma concentration of propofol immediately after 2 mg/kg infusion was measured. Multiple regression analysis showed that, in addition to age and weight, cardiac output was a small but significant factor for predicting the hypnotic dose of propofol (R(2) = 0.468, P < 0.001), the time to hypnosis (R(2) = 0.454, P < 0.001), and the plasma concentration of propofol (R(2) = 0.248, P < 0.01). Cardiac output, age, and weight showed similar partial coefficients for the hypnotic dose (0.128, 0.137, and 0.140, respectively). This study demonstrates a significant relationship between cardiac output and the hypnotic dose of propofol. We suggest that anesthesiologists should include cardiac output, as well as age and weight, in calculating the induction dose of propofol.

Small dose midazolam or droperidol reduces the hypnotic dose of propofol at the induction of anaesthesia

We investigated the effect of a small dose of midazolam, ketamine, droperidol or lidocaine on the propofol dose required for hypnosis during induction of general anaesthesia. These drugs were randomly administered to 100 patients about to undergo scheduled surgery. Propofol was then infused at a rate of 250 microg kg-1 min-1 and the hypnotic dose to produce hypnosis was evaluated. Midazolam (20 microg kg-1) and droperidol (20 microg kg-1) significantly reduced the mean hypnotic dose of propofol (mean) S.D.) compared with the placebo (43.7 +/- 17.8 mg, 61.9 +/- 10.6 mg and 72.5 +/- 27.7 mg after pretreatment with midazolam, droperidol and placebo, respectively), whereas ketamine (0.1 mg kg-1) and lidocaine (1 mg kg-1) did not significantly affect the hypnotic dose of propofol (63. 1 +/- 25.6 mg and 65.1 +/- 24.8 mg, respectively). Only midazolam when compared with saline administration, (176 +/- 66 s and 298 +/- 126 s, respectively), shortened the time to achieve hypnosis. The changes in blood pressure (non-invasive) and heart rate were not significantly different in all groups during the induction of anaesthesia and oro-tracheal intubation. These results raise the possibility that new combinations of central nervous system drugs, such as droperidol and propofol, have a potential to reduce the dose of intravenous anaesthetics, including propofol, that produce hypnosis without significant adverse effects.