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Background: This study aimed to determine the accuracy of commonly used preoperative difficult airway indices as predictors of difficult mask ventilation (DMV) in obese patients (BMI >30 kg/m2)., Methods: In 309 consecutive obese patients undergoing general surgery, the modified Mallampati test, patient's Height/Thyromental distance ratio, Inter-Incisor Distance, Protruding Mandible (PM), history of Obstructive Sleep Apnea and Neck Circumference (NC) were recorded preoperatively. DMV was defined as Grade 3 mask ventilation (MV) by the Han's scale (MV inadequate, unstable or requiring two practitioners). Data are shown as means±SD or number and proportions. Independent DMV predictors were identified by multivariate analysis. The discriminating capacity of the model (ROC curve area) and adjusted weights for the risk factors (odds ratios) were also determined., Results: BMI averaged 42.5±8.3 kg/m2. DMV was reported in 27 out of 309 patients (8.8%; 95%CI 5.6-11.9%). The multivariate analysis retained NC (OR 1.17; P<0.0001), limited PM (1.99; P=0.046) and Mallampati test (OR 2.12; P=0.009) as risk predictors for DMV. Male gender was also included in the final model (OR 1.87; P=0.06) as biologically important variable albeit the borderline statistical significance. The model yielded a good discriminating capacity (ROC curve 0.85). The four parameters were used to create an unweighted prediction score (ROC curve 0.84) with >2 associated factors as the best discriminating point for DMV., Conclusion: Obese patients show increased incidence of DMV with respect to the undifferentiated surgical population. Limited PM, Mallampati test and NC are important DMV predictors.

Objective: To evaluate the sedative effect of acupuncture in healthy volunteers by means of the BIS monitor. Secondary end-points were the evaluation of subjective sedative sensation induced by acupuncture and possible lasting of the sedative effect post needles removal., Methods: We performed a cross-over, single-blinded study on 10 healthy volunteers to evaluate objective and subjective sedative effect of acupuncture compared to sham acupuncture. We recorded heart rate, pulse-oxymetry, BIS at baseline, during a 20-min. stimulation period, and for the following 20 minutes after needles removal. Besides, we asked volunteers to score their subjective state by VAS at baseline, after the stimulation period (20th minute) and 20 minutes after needles removal., Results: BIS values were not significantly different between true and sham acupuncture. A suggestive but not statistically significant difference was evident in VAS score, with true- better than sham acupuncture. There was no difference in the incidence of sleep during the experimental phases, nor in the incidence of insomnia or somnolence in the following 24 hours. HR and SpO2 remained always in a normal range., Conclusions: The sedative effect of true acupuncture was not different from that of sham acupuncture in healthy volunteers. We suggest that acupuncture could have a mild sedative action that can be demonstrated only treating anxious patients and not calm volunteers. In our opinion, the low potency of this technique can be an advantage allowing acupuncture safe application in a wide range of settings.

Objective: To investigate the release of cardiac biomarkers (troponin I and CK-MB) in patients undergoing coronary artery bypass graft (CABG) with or without cardiopulmonary bypass (CPB)., Design: Prospective study., Setting: University tertiary hospital., Participants: Sixty-five consecutive patients undergoing coronary artery bypass grafting (>or=2 vessel disease, ejection fraction >or=0.35%, elective procedure)., Interventions: Cardiac biomarkers were measured before surgery, at intensive care unit arrival, 4 and 18 hours after the end of the procedure., Measurements and Main Results: Cardiac biomarker release was higher in on-pump than in off-pump patients at every time point. On multivariate analysis, CPB (p < 0.0001), number of distal grafts (p = 0.005), and hypertension treatment (p = 0.03) were the only independent predictors of peak cardiac troponin release., Conclusions: Cardiac troponin I release after multivessel CABG is associated with the technique. Different values for the normal range should be considered. OPCABG is minimally invasive for the heart as far as myocardial marker release is concerned.

Objective: The purpose of this study was to determine whether coronary artery bypass grafting (CABG) surgery on the beating heart (BH) is associated with reduction of R-wave potentials on the precordial leads on the surface electrocardiogram (ECG) as previously shown for CABG with cardiopulmonary bypass., Methods: Fifty-four patients undergoing CABG surgery at a single tertiary care university hospital were analyzed. Patients suffering a postoperative cardiac event (myocardial infarction) or nonspecific ECG changes were excluded. ECG results were recorded at arrival in the intensive care unit, after 4 and 18 hours postoperatively; simultaneously, myocardial cell damage biomarkers (CK-MB and cTnI) were assayed. A control group of 31 patients undergoing mitral valve repair was also evaluated., Results: Patients operated with the BH (OPCABG) technique did not show any decrease of R-wave amplitude at 0, 4, and 18 hours postoperatively; whereas those operated with CPB, both for coronary artery surgery and for mitral repair, had a similar extent and pattern of R-wave reduction. The release of myocardial necrosis markers was significantly lower in coronary artery patients operated with BH than in those operated with CPB; however, no statistically significant correlation between the ECG changes and release of myocardial cell damage markers was observed in any of the groups., Conclusions: The findings indicate, for the first time, that CABG surgery on the BH is not followed by any reduction of R-wave amplitude on precordial leads and confirms that the BH technique is associated with a lower release of myocardial cell damage markers.

Background: To compare passive thermal insulation by reflective blankets with forced-air active warming on the efficacy of normothermia maintenance and time for discharging from the recovery room after combined spinal/epidural anesthesia for total hip arthroplasty., Design: Prospective, randomized study., Setting: Inpatient anesthesia at three University Departments of orthopedic surgery., Patients: 50 ASA physical status I-III patients, who were scheduled for elective total hip arthroplasty., Interventions: Patients received combined spinal/epidural anesthesia (CSE) with intrathecal injection of 15 mg of 0.5% hyperbaric bupivacaine. All procedures started 8-10 a.m., and operating room temperature was maintained between 21-23 degrees C, with relative humidity ranging between 40-45%. As warming therapy patients received either passive thermal insulation of the trunk, the two upper limbs and the unoperated lower limb with reflective blankets (group passive, n = 25), or forced-air active warming of the two upper limbs (group active, n = 25). Core temperature was measured before CSE placement (baseline), and then every 30 min until recovery of normothermia., Results: Demographic data, duration of surgery, intraoperative blood losses, and crystalloid infusion were similar in the two groups. Arterial blood pressure decreased in both groups compared with baseline values, while no differences in heart rate were observed during the study. Core temperatures in passive group patients decreased more markedly than in actively warmed patients, with a 1 degree C difference between the two groups at the end of surgery (p < 0.0005). At recovery room entry seven patients in group active (24%) and 16 patients in group passive (64%) showed a core temperature < 36 degrees C (p < 0.01). Achievement of both discharging criteria and normothermia required 32 +/- 18 min in active group and 74 +/- 52 min in passive group (p < 0.0005)., Conclusions: Forced-air cutaneous warming allows the anesthesiologist to maintain normothermia during combined spinal/epidural anesthesia for total hip replacement even if the convective blanket is placed on a relatively small skin surface with reflex vasoconstriction. Maintaining core normothermia decreased the duration of postanesthesia recovery and may, therefore, reduce costs of care.

Unlabelled: To determine the target plasma concentration of propofol required to place either a laryngeal mask airway (LMA) or a cuffed oropharyngeal airway (COPA), we started a continuous target-controlled infusion of propofol in 60 ASA physical status I or II unpremedicated patients scheduled for minor orthopedic surgery with peripheral nerve block. The target plasma concentration of propofol was initially set at 2 microg/mL. When the effect-site calculated concentration of propofol was equal to the plasma concentration according to the computer simulation, the target plasma concentration was increased by 0.5-microg/mL steps until successful placement of either the LMA (n = 30) or the COPA (n = 30). The mean target plasma concentration of propofol required to place a LMA was 4.3 +/- 0.8 microg/mL compared with 3.2 +/- 0.6 microg/mL to place a COPA (P < 0.001). To successfully place the airways in 95% of patients, the target plasma concentration of propofol had to be increased up to 4 microg/mL for the COPA and 6 microg/mL for the LMA. We conclude that placing a LMA in healthy, unpremedicated patients requires target plasma concentrations of propofol higher than those required for placing a COPA., Implications: We evaluated the use of target-controlled infusion of propofol to place extratracheal airways in this prospective, randomized study and demonstrated that the target plasma concentration of propofol required to successfully place a laryngeal mask in >95% of healthy, unpremedicated patients is 6 microg/mL, compared with 4 microg/mL to place a cuffed oropharyngeal airway.

Purpose: To determine the plasma concentrations of propofol required to achieve different levels of sedation during monitored anesthesia care., Methods: Sixty ASA I-II, 18-65 yr-old patients, received a target-controlled continuous iv infusion of propofol. The target plasma concentration of propofol (Cpt) was initially set at 0.4 microg x ml(-1). Two minutes after calculated equilibrium between plasma and effect-site concentrations, the Cpt of propofol was increased by 0.2 microg x ml(-1) steps until the patient showed no reaction to squeezing the trapezius. The level of sedation was assessed immediately before each increase in propofol Cpt using the Observer's Assessment of Alertness/Sedation (OAA/S) scale., Results: The Cpt of propofol required to induce lethargic response to name was 1.3 microg x ml(-1) (5 degrees and 95 degrees percentiles: 1.0 - 1.8 microg x ml(-1)), to obtain response after loud and repeated calling name was 1.7 microg x ml(-1) (1.2 - 2.2 microg x ml(-1)), to obtain response after prodding or shaking was 2.0 microg x ml(-1) (1.6 - 2.6 microg x ml(-1)), to obtain response after squeezing the trapezius was 2.4 microg x ml(-1) (1.8 - 3.0 microg x ml(-1)). Patients showed no response after squeezing the trapezius at 2.8 microg x ml(-1) (2.0 - 3.6 microg x ml(-1)). Correlation between Cpt propofol and sedation scores were r = 0.76, P < 0.0001., Conclusions: Target-controlled infusion of propofol provided easy and safe management of intraoperative sedation, allowing fast and predictable deepening in the level of sedation, while minimizing systemic side effects of intravenous sedation due to the minimal risk of overdosing the drug.

Unlabelled: The purpose of this investigation was to compare, in a prospective, double-blinded fashion, 0.5% and 0.75% ropivacaine with 2% mepivacaine to determine their effects on respiratory function during interscalene brachial plexus (IBP) anesthesia. With ethical committee approval and written, informed consent, 30 healthy patients presenting for elective shoulder capsuloplastic or acromioplastic procedures were randomized to receive IBP anesthesia by 20 mL of either 0.5% ropivacaine (n = 10), 0.75% ropivacaine (n = 10), or 2% mepivacaine (n = 10). Block onset time, pulmonary function variables, ipsilateral hemidiaphragmatic motion (ultrasonographic evaluation), and first requirement of postoperative analgesic were evaluated. Surgical anesthesia (loss of pinprick sensation from C4 to C7 and motor block of the shoulder joint) was achieved later with 0.5% ropivacaine than with either 0.75% ropivacaine or 2% mepivacaine (P < 0.05), whereas the first pain medication was requested later with both ropivacaine concentrations than with mepivacaine (P < 0.0005). No differences in quality of the block or patient acceptance were observed in the three groups. All 30 patients had ipsilateral hemidiaphragmatic paresis and large mean decreases in forced vital capacity (ropivacaine 0.5%: 40% +/- 17%, ropivacaine 0.75%: 41% +/- 22%, mepivacaine 2%: 39% +/- 21%) and forced expiratory volume at 1 s (ropivacaine 0.5%: 30% +/- 19%, ropivacaine 0.75%: 38% +/- 26%, mepivacaine 2%: 40% +/- 10%). We conclude that, when performing IBP anesthesia, 0.5% ropivacaine does not decrease the incidence of ipsilateral paresis of the hemidiaphragm compared with 0.75% ropivacaine and 2% mepivacaine., Implications: During the first 30 min after placing interscalene brachial plexus anesthesia, 0.5% ropivacaine does not provide clinically relevant advantages in terms of pulmonary function changes compared with either 0.75% ropivacaine or 2% mepivacaine. However, 0.75% ropivacaine allows a short onset, similar to that of mepivacaine, with long postoperative analgesia.

Purpose: To evaluate the effects of hyperbaric bupivacaine concentration in producing unilateral spinal anaesthesia., Methods: With Ethical Committee approval and written consent, 60 patients undergoing lower limb surgery were placed in the lateral position with the side to be operated on dependent. After dural puncture (25-gauge Whitacre spinal needle), the needle hole was turned toward the dependent side and patients were randomly assigned to receive 8 mg of either 0.5% (Group0.5%, n = 30) or 1% (Group1%, n = 30) hyperbaric bupivacaine. The lateral position was maintained for 15 min, while a blinded observer recorded loss of pinprick sensation and degree of motor block on both sides until two segment regression of sensory level on the dependent side., Results: At the end of the 15 min lateral position spinal anaesthesia was more frequently unilateral in Group0.5% (80%) than in Group1% (53%)(P < 0.05). However, 30 min after patients were turned supine, unilateral spinal anaesthesia decreased to 60% of cases in Group0.5% and 40% of cases in Group1% (P = NS). The maximum sensory level on the dependent side [T10(L1-T2) in Group0.5% and T8 (T12-T3) in Group1%], time to reach it [20 (5-30) min in Group0.5% and 25 (10-35) min in Group1%], and time to two segment regression of sensory level [80 (30-135) min in Group0.5% and 75 (20-135) min in Group1%] were similar in both groups., Conclusion: Highly concentrated solutions of hyperbaric bupivacaine are not advantageous in obtaining a unilateral spinal anaesthesia, when a small anaesthetic dose is injected slowly through a Whitacre spinal needle.