Background: Peri-operative hymodynamic instability is one of the major concerns for anesthesiologists when performing general anesthesia for individuals with autonomic dysfunction. The purpose of this study was to examine the potential usage of pre-operative measurement of heart rate variability (HRV) in identifying which individuals, with or without diabetes, may be at risk of blood pressure (BP) instability during general anesthesia. Methods: We studied 46 patients with diabetes and 87 patients without diabetes ASA class II or III undergoing elective surgery. Participants' cardiovascular autonomic function and HRV were assessed pre-operatively, and hymodynamic parameters were monitored continuously intra-operatively by an independent observer. Results: Only 6% of the participants were classified as having cardiovascular autonomic neuropathy (CAN) based on traditional autonomic function tests whereas 15% experienced hypotension. Total power (TP, P ¼ 0.006), low frequency (LF, P ¼ 0.012) and high frequency (HF, P ¼ 0.028) were significantly lower in individuals who experienced hypotension compared with those who did not. Multivariate logistic regression analysis revealed that TP [odds ratio (OR) ¼ 0.15, 95%

As expected, dexmedetomidine is not as effective an analgesic as the opioid remifentanil. The difference in the quality of the analgesia with remifentanil may be a reflection of a different mechanism of action or a consequence of the sedative effect of dexmedetomidine.

Objective The objective of this study was to determine the pharmacokinetics of lidocaine in a 48-hour infusion in patients undergoing cardiac surgery with cardiopulmonary bypass. Design A retrospective substudy of a clinical trial assessing the efficacy of intravenous lidocaine for postoperative cognitive decline. Setting University hospital. Participants 99 patients undergoing cardiac surgery with cardiopulmonary bypass. Interventions After induction of anesthesia, lidocaine was administered as bolus of 1 mg/kg and followed by a continuous infusion at 4 mg/min for the first hour, 2 mg/min for the second hour, and 1 mg/min for the next 46 hours. Measurements and Main Results Blood samples were taken at baseline, end of cardiopulmonary bypass, and 24 and 48 hours after cardiopulmonary bypass for measurement of plasma concentration of lidocaine. Lidocaine levels increased significantly over time despite a constant rate of infusion (p < 0.05). The pharmacokinetics of lidocaine was best described by a two-compartment model and body weight was found to be a significant factor for the volume of the central compartment and clearance. The final pharmacokinetic parameters were V1(L) = 0.0619*weight, V2(L) = 187, CL1(L/min) =0.00419*weight, CL2(L/min) = 8.92. Conclusions A two-compartment pharmacokinetic model best describes the plasma concentrations of 48-hour lidocaine infusion in patients undergoing heart surgery with cardiopulmonary bypass. The inclusion of body weight as a covariate on clearance and central compartment improves the model. Lidocaine infusions should be dosed by body weight and decreased after 24 hours to avoid potential toxicity in long-term infusions.

BACKGROUND:Age is an important determinant of the pharmacokinetic profile of inhaled anesthetics. The influence of age on the dynamic profile of sevoflurane's effect has not been well described. We performed this study to characterize the influence of age and other covariates on the dynamic relationship between sevoflurane end-tidal concentration (C ET ) and its effect measured by bispectral index (BIS). METHODS: Fifty patients, aged 3-71 yr, scheduled for minor surgery were prospectively studied. The BIS and sevoflurane C ET were continuously measured during the study period. During maintenance of anesthesia and after stable BIS values of 60 -65 were obtained, the inspired concentration of sevoflurane was increased to 5 vol % for 5 min or until BIS Ͻ40 and then decreased. The dynamic relationship between sevoflurane C ET and its effect as measured by BIS during this transition period were modeled with an inhibitory E max model using a population pharmacokinetic-pharmacodynamic approach with NONMEM V. A predictive check method was used to validate the final model. RESULTS: The sensitivity to sevoflurane's effect as measured by BIS expressed in the C 50 [steady-state C ET eliciting half of maximum response (I max )] increased with age. The speed of change of sevoflurane's effect, expressed as the effect-site equilibration half-life (t 1/2 k e0 ), increased at older ages. The predictive check analysis confirmed the adequacy of the model. CONCLUSIONS: Age significantly affects the dynamic relationship between sevoflurane C ET and its effect measured with BIS.

Premedication with mirtazapine 30 mg reduces the level of preoperative anxiety and the risk of PONV in moderate and high-risk female patients.

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Parturients with greater abdominal circumference value have a higher level of sensory blockade at 5 minutes after spinal anesthesia. Abdominal circumference cannot predict the maximum sensory blockade level and the incidence of hypotension.