Gender Affects the Median Effective Dose and 95% Effective Dose of Oxycodone for Blunting the Hemodynamic Response to Tracheal Intubation in Narcotic-Naïve Adult Patients.

BACKGROUND: Intravenous (IV) oxycodone has been used at induction to prevent an intubation reaction. The aims of the current study were to calculate the median effective dose (ED50) and the 95% effective dose (ED95) of an IV bolus of oxycodone that blunts the hemodynamic response to tracheal intubation with propofol according to gender and to observe the adverse events of induction-dose oxycodone. METHODS: Adult patients who required general anesthesia and tracheal intubation were enrolled. Tracheal intubation was performed using unified TD-C-IV video laryngoscopy and an ordinary common endotracheal tube. Dixon's up-and-down method was used to obtain ED50data for women and men separately. The initial dose of oxycodone was 0.2 mg/kg for women and 0.3 mg/kg for men (step size was 0.01 mg/kg). Next, a dose-response curve from the probit analysis was generated to determine the ED50and ED95to blunt the intubation reaction in female and male patients. Adverse events following oxycodone injection were observed for 5 min before propofol injection. RESULTS: Sixty-three patients were analyzed, including 29 females and 34 males. According to the probit analysis, the ED50 and ED95of oxycodone required to blunt the intubation reaction in women were 0.254 mg/kg (95% confidence interval [CI], 0.220-0.328 mg/kg) and 0.357 mg/kg (95% CI, 0.297-2.563 mg/kg), respectively. In men, the ED50 and ED95were 0.324 mg/kg (95% CI, 0.274-0.381 mg/kg) and 0.454 mg/kg (95% CI, 0.384-2.862 mg/kg), respectively. Men required 28% more oxycodone than women for induction (P < 0.01). The most common adverse events were dizziness (87.3%), vertigo (66.7%), sedation (74.6%), and respiratory depression (66.7%). CONCLUSIONS: Oxycodone can be used for induction to prevent intubation reactions. Gender affected the ED50and ED95of oxycodone for blunting the tracheal intubation reaction.

Anesthetic considerations for patients with acute cervical spinal cord injury.

Anesthesiologists work to prevent or minimize secondary injury of the nervous system and improve the outcome of medical procedures. To this end, anesthesiologists must have a thorough understanding of pathophysiology and optimize their skills and equipment to make an anesthesia plan. Anesthesiologists should conduct careful physical examinations of patients and consider neuroprotection at preoperative interviews, consider cervical spinal cord movement and compression during airway management, and suggest awake fiberoptic bronchoscope intubation for stable patients and direct laryngoscopy with manual in-line immobilization in emergency situations. During induction, anesthesiologists should avoid hypotension and depolarizing muscle relaxants. Mean artery pressure should be maintained within 85-90 mmHg (1 mmHg = 0.133 kPa; vasoactive drug selection and fluid management). Normal arterial carbon dioxide pressure and normal blood glucose levels should be maintained. Intraoperative neurophysiological monitoring is a useful option. Anesthesiologists should be attentive to postoperative respiratory insufficiency (carefully considering postoperative extubation), thrombus, and infection. In conclusion, anesthesiologists should carefully plan the treatment of patients with acute cervical spinal cord injuries to protect the nervous system and improve patient outcome.

The effect of epidural lidocaine administration on sedation of propofol general anesthesia: a randomized trial.

STUDY OBJECTIVE: To examine the influence of epidural and intravenous (IV) lidocaine, and height of the epidural sensory block, on the dose of propofol required for induction of general anesthesia. DESIGN: Randomized controlled study. SETTING: University hospital. PATIENTS: 66 adult, ASA physical status 1 and 2 patients, aged 25 to 65 years, undergoing elective abdominal surgery. INTERVENTIONS: Patients were randomized to 4 groups: the epidural saline control group (Group C; L2-L3 puncture, epidural and IV saline), the IV lidocaine group (Group IV; L2-L3 puncture, saline epidural, IV lidocaine 1 mg/kg), the lumbar epidural lidocaine group (Group EL; L2-L3 puncture, 1.5% lidocaine epidural, IV saline), and the thoracic epidural lidocaine group (Group ET; T9-T10 puncture, 1.5%lidocaine epidural, IV saline). Two minutes after the beginning of the infusion of IV lidocaine or saline, propofol anesthesia was initiated. MEASUREMENTS: Mean arterial blood pressure (MAP), heart rate (HR), and sensory block height were monitored. The induction dose of propofol, its estimated effect-site concentration (Ce), and plasma concentration were measured at various time points. Finally, we recorded the time taken for the bispectral index (BIS) to decrease to 60, the plasma concentration of lidocaine at induction, and the occurrence of adverse events. The induction time (when BIS reached 60) also was recorded. MAIN RESULTS: The induction propofol dose, Ce, and plasma concentration of propofol when BIS equaled 60 were significantly lower in Group IV, Group EL, and Group ET than Group C. The above parameters in Group ET (T9 - T10 puncture) were significantly less than in Group EL (L2 - L3 puncture). The induction doses of propofol and plasma concentration of propofol and lidocaine were significantly higher in Group IV than in Groups EL or ET. CONCLUSIONS: Epidural and IV lidocaine reduce the dose of propofol required to induce general anesthesia. Administration of lidocaine via the epidural route reduces anesthetic requirements more so than the IV route. Propofol requirements were further reduced in patients with higher sensory epidural block.

[Out-of-hospital cardiopulmonary resuscitation needs the ventilation].

Cardiopulmonary resuscitation (CPR) is series of rescue measures for saving cardiac arrest patients. Early initiation and good quality of CPR is crucial for increasing chance of survival from out-of-hospital cardiac arrest. In recent years, the CPR guidelines have changed a lot, especially in basic life support. The guideline now pays more attention on chest compression and less to ventilation. CPR with chest compression only and without mouth-to-mouth ventilation is more popular. In this article, we outline the development and recent researches of CPR. As depriving oxygen from a collapsed patient for 6 min may result in poor outcome, the average time for ambulance transport is longer (about 10 to 16 min) in China, which makes rescuers easy to feel fatigue, chest compression only CPR is not suitable in China. Though non-professional rescuers have difficulty to perform mouth-to-mouth ventilation, they generally show a willingness to do so. To strengthen public standard CPR training including mouth-to-mouth ventilation and chest compression, is most important to promote CPR in China.

Effectiveness of breathing through nasal and oral routes in unconscious apneic adult human subjects: a prospective randomized crossover trial.

BACKGROUND: The authors hypothesized that mouth ventilation by a resuscitator via the nasal route ensures a more patent airway and more effective ventilation than does ventilation via the oral route and therefore would be the optimal manner to ventilate adult patients in emergencies, such as during cardiopulmonary resuscitation. They tested the hypothesis by comparing the effectiveness of mouth-to-nose breathing (MNB) and mouth-to-mouth breathing (MMB) in anesthetized, apneic, adult subjects without muscle paralysis. METHODS: Twenty subjects under general anesthesia randomly received MMB and MNB with their heads placed first in a neutral position and then an extended position. A single operator performed MNB and MMB at the target breathing rate of 10 breaths/min, inspiratory:expiratory ratio 1:2 and peak inspiratory airway pressure 24 cm H2O. A plethysmograph was used to measure the amplitude change during MMB and MNB. The inspiratory and expiratory tidal volumes during MMB and MNB were calculated retrospectively using the calibration curve. RESULTS: All data are presented as medians (interquartile ranges). The rates of effective ventilation (expired volume > estimated anatomic dead space) during MNB and MMB were 91.1% (42.4-100%) and 43.1% (42.5-100%) (P < 0.001), and expired tidal volume with MMB 130.5 ml (44.0-372.8 ml) was significantly lower than with MNB 324.5 ml (140.8-509.0 ml), regardless of the head position (P < 0.001). CONCLUSIONS: Direct mouth ventilation delivered exclusively via the nose is significantly more effective than that delivered via the mouth in anesthetized, apneic adult subjects without muscle paralysis. Additional studies are needed to establish whether using this breathing technique during emergency situations will improve patient outcomes.

Continuous versus bolus cardiac output monitoring during orthotopic liver transplantation.

BACKGROUND: Cardiac output monitoring is important for critical patients. This study aimed to determine the delayed response of continuous cardiac output (CCO) thermodilution measurement, whether CCO and bolus cardiac output (BCO) thermodilution agree sufficiently to be used interchangeably, and whether CCO monitoring is reliable for patients undergoing liver transplantation. METHODS: Thirteen patients undergoing liver transplantation without veno-venous bypass were studied (37-66 years old, weight 46-75 kg). Continuous and bolus thermodilution measurements were performed at predefined time points using an "Opti-Q" SvO2/CCO monitor (Abbott Laboratories, North Chicago, IL, USA). Bias and 95% limits of agreement were calculated according to Bland and Altman analysis. The limits of agreement by which two methods are judged to be interchangeable were defined in advance as +/-(13%XBCOmean) L/min. The repeatability and relative error of CCO, and the differences between CCO and the mean of the two measurements were calculated. RESULTS: Cardiac output measurements yielded 196 data pairs with ranges of 1.9 to 17.9 L/min for CCO and 2.1 to 18.3 L/min for BCO. The response time of CCO was delayed in the early phases after caval clamping and after reperfusion. At most of the measurement points, bias and 95% limits of agreement were -0.18+/-1.91 L/min. 95% limits of agreement did not fall within the predetermined limits of agreement of +/-1.14 L/min. The repeatability coefficient of CCO was 0.36 L/min and the relative error was 4.6+/-4.7%. The mean difference between CCO and the average of the two methods was -0.09 L/min (0.49 L/min). CONCLUSIONS: In patients undergoing liver transplantation, the delayed response of CCO limits its application during the early phases after caval clamping and after reperfusion of the graft. The two methods are not interchangeable even in hemodynamic stability. Continuous thermodilution monitoring, however, is reliable or acceptable for clinical purposes.

Dynamics of vascular volume and hemodilution of lactated Ringer's solution in patients during induction of general and epidural anesthesia.

OBJECTIVE: To investigate the dynamics of vascular volume and the plasma dilution of lactated Ringer's solution in patients during the induction of general and epidural anesthesia. METHODS: The hemodilution of i.v. infusion of 1000 ml of lactated Ringer's solution over 60 min was studied in patients undergoing general (n=31) and epidural (n=22) anesthesia. Heart rate, arterial blood pressure and hemoglobin (Hb) concentration were measured every 5 min during the study. Surgery was not started until the study period had been completed. RESULTS: General anesthesia caused the greater decrease of mean arterial blood pressure (MAP) (mean 15% versus 9%; P<0.01) and thereby followed by a more pronounced plasma dilution, blood volume expansion (VE) and blood volume expansion efficiency (VEE). A strong linear correlation between hemodilution and the reduction in MAP (r=-0.50; P<0.01) was found. At the end of infusion, patients undergoing general anesthesia retained 47% (SD 19%) of the infused fluid in the circulation, while epidural anesthesia retained 29% (SD 13%) (P<0.001). Correspondingly, a fewer urine output (mean 89 ml versus 156 ml; P<0.05) and extravascular expansion (454 ml versus 551 ml; P<0.05) were found during general anesthesia. CONCLUSION: We concluded that the induction of general anesthesia caused more hemodilution, volume expansion and volume expansion efficiency than epidural anesthesia, which was triggered only by the lower MAP.

[Determination of propofol in cerebral spinal fluid by HPLC with fluorescence detection].

OBJECTIVE: To establish a method for determining propofol in human cerebrospinal fluid (CSF). METHODS: Reverse phase high-performance liquid chromatography (HPLC) with fluorescence detection was applied to quantitative analysis. CSF samples were centrifuged (12,500 r/min for 3 min) and filtered (the diameter of the filter is 0.45 microm). Twenty mul of supernatant was directly injected and separated by Supelco Discovery C(18)column. The mobile phase was composed of methanol-water (80:20); the flow rate was 1 ml/min, and the column temperature was 30 degree. The fluorescence detective waves were: lambda ex=276 nm and lambda em=310 nm. RESULTS: The linear range of propofol in CSF was 5-200 ng/ml (r=0.9994). The recovery rates for high, intermediate and low concentrations were 101.2%, 99.8%, 98.8%, respectively. The RSD of inter-day assay was 1.55%, 1.73%, 6.01% and it of intra-day assay was 1.69%, 2.37%, 8.60%. The limit of detection proved to be 2 ng/ml. CONCLUSION: The method is rapid, simple, accurate and sensitive for measurement of propofol concentration in CSF.