Effects of remifentanil, nitroglycerin, and sevoflurane on the corrected QT and Tp-e intervals during controlled hypotensive anesthesia

Effects of Osteotomy on Hemodynamic Parameters and Depth of Anesthesia in Rhinoplasty Operations

BACKGROUND

Bleeding during rhinoplasty leads to many undesirable effects, such as loss of vision in the surgery area, complications during the procedure, and postoperative complications. The most important effect that increases bleeding is hemodynamic changes during surgery. Considering that osteotomy is the most challenging process in rhinoplasty, this study aimed to examine the hemodynamic changes during osteotomy and changes in the depth of anesthesia.

METHODS

A total of 50 patients, aged 18 to 65 years with an ASA (American Society of Anesthesiology) score of 1 and 2, who underwent osteotomy during rhinoplasty under general anesthesia, were examined retrospectively. After routine monitoring, the patients underwent general anesthesia induction and endotracheal intubation. Before the surgery, they received remifentanil 1 μg/kg as an intravenous bolus followed by 0.5 μg/(kg·min) as intravenous infusion until the end of the surgery. The hemodynamic parameters and depth of anesthesia [bispectral index (BIS) values] of the patients were examined before anesthesia, 10 minutes before osteotomy, during osteotomy, and 10 minutes after osteotomy.

RESULTS

A significant difference was found in heart rate (beats/min), systolic and diastolic blood pressures (mm Hg), and BIS values of the patients measured before, during, and after osteotomy (P < 0.001). The heart rate, systolic and diastolic blood pressures, and BIS values were significantly higher during osteotomy. Until the 10th minute after osteotomy, all 4 parameters nearly reached the values measured before osteotomy.

CONCLUSIONS

Osteotomy directly affects hemodynamic parameters and depth of anesthesia. Hence, it is of utmost importance that the analgesic need and depth of anesthesia are adequately monitored and adjusted during osteotomy. By suppressing hemodynamic stress responses, the amount of bleeding can be reduced, thus increasing the surgical success and the patient's comfort.

Remifentanil postconditioning ameliorates histone H3 acetylation modification in H9c2 cardiomyoblasts after hypoxia/reoxygenation via attenuating endoplasmic reticulum stress

Remifentanil postconditioning (RPC) elicits cardioprotection against ischemia/reperfusion injury (IRI) by attenuating apoptosis associated with endoplasmic reticulum stress (ERS). Histone H3, acetylation modifications of histone H3, and histone deacetylases (HDAC) also have key roles in the mediation of the survival and apoptosis of cardiomyocytes. In this study, an in vitro IRI model was established with H9c2 cardiomyoblasts to investigate the role of histone H3 acetylation and HDAC3 in RPC-induced attenuation of ERS-associated apoptosis. Briefly, H9c2 cardiomyoblasts were randomly subjected to hypoxia/reoxygenation with and without remifentanil administered at the onset of reoxygenation. Results showed that RPC increased cell viability and prevented cell apoptosis (evidenced by CCK-8 cell viability assays and flow cytometry), and these effects were accompanied by lower levels of expression of GRP78, CHOP, cleaved caspase-12, and cleaved caspase-3. RPC also mimicked the effects of SAHA by increasing the amount of histone H3 deacetylation and decreasing up-regulation of HDAC at both the mRNA and protein levels in response to HR. Finally, RPC-induced protective effects against HR, including attenuation of ERS-associated protein markers, deacetylation of histone H3, and down-regulation of HDAC3 were completely abolished by pretreatment with thapsigargin (TG, a specific ERS activator). In contrast, these effects were not found to be enhanced after pretreatment with 4-phenyl butyric acid (4-PBA, a widely used ERS inhibitor). The present results demonstrate that RPC protects H9c2 cardiomyoblasts from HR injury, and this protection involves an attenuation of ERS-associated apoptosis, which mediates a reduction in HDAC3 expression and an increase in histone H3 deacetylation.

Effects of remifentanil with or without midazolam pretreatment on the 95% effective dose of propofol for loss of consciousness during induction: A randomized, clinical trial

BACKGROUND

Propofol is a rapid, efficient hypnotic agent with antiemetic effects. However, a high dosage is related to hemodynamic abnormalities such as hypotension and bradycardia. Pretreatment with remifentanil can decrease injection pain and stabilize hemodynamics during the induction period. Remifentanil or midazolam in combination with propofol can provide synergistic or additive effects during anesthesia induction. However, the hypnotic doses of propofol required in patients who receive pretreatment with remifentanil or midazolam remain unclear.

METHODS

Patients aged 20 to 50 years who were scheduled to undergo surgery under general anesthesia were enrolled in this study. The patients were randomized into 3 groups using a computer-generated randomization table. Patients in Group P (Propofol) received only propofol for loss of consciousness, those in Group PR (Propofol-Remifentanil) received remifentanil prior to propofol, and those in Group PMR (Propofol-Midazolam-Remifentanil) received remifentanil and midazolam prior to propofol. After propofol administration, loss of both the eyelash reflex and verbal response represented success. The 95% effective dose of propofol for loss of consciousness in each group, which was the primary outcome, was determined using a modified biased coin up-and-down method.

RESULTS

A total of 124 patients were initially enrolled. Of these, 4 were excluded, and the remaining 120 patients were randomized to each (n = 40) of the 3 groups. The 95% effective dose of propofol for loss of consciousness was 1.74 , 1.38, and 0.92 mg/kg in Groups P, PR, and PMR, respectively. Blood pressure decreased at 2 minutes after propofol administration in all the groups. However, compared with Group P, Groups PR and PMR exhibited a significant decrease in blood pressure.

CONCLUSIONS

The effective dose of propofol for loss of consciousness could be decreased by 21% and 47% when remifentanil pretreatment was used without and with midazolam, respectively. However, the decrease in blood pressure was greater with pretreatment than sole propofol use. These findings suggest that the combination of remifentanil with or without midazolam may have no benefit on hemodynamic stability during induction using propofol.

TRIAL REGISTRATION

NCT02536690 (clinicaltrials.gov).