ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundRecent studies have determined that an initial rectal acetaminophen dose of approximately 40 mg/kg is needed in children to achieve target antipyretic serum concentrations. The timing and amount of subsequent doses after a 40-mg/kg dose has not been clarified for this route of administration. Based on the authors’ previous pharmacokinetic data, they examined whether a 40-mg/kg loading dose followed by 20-mg/kg doses at 6-h intervals maintain serum concentrations within the target range of 10–20 &mgr;g/ml, without evidence of accumulation.MethodsChildren (n = 16) received rectal acetaminophen (40 mg/kg) and up to three additional doses of 20 mg/kg at 6-h intervals. Venous blood samples were taken every 30 min for 4 h, then every 60 min for 4 h, and every 4 h for 16 h. The authors assessed whether their published pharmacokinetic parameters predicted the acetaminophen concentrations in the present study. They also assessed their dosing regimen by determining the fraction of time each individual maintained the target concentration.ResultsAll patients received the initial loading dose; 10 of 16 patients received three subsequent doses. Serum concentrations with the initial dose were in the target range 38 ± 25% of the time. With subsequent dosing, the target range was maintained 60 ± 29% of the time. The highest serum concentration with initial or subsequent dosing was 38.6 &mgr;g/ml. Pharmacokinetic parameters from the earlier study predicted the serum concentrations observed for both initial and subsequent doses.ConclusionsA rectal acetaminophen loading dose of 40 mg/kg followed by 20-mg/kg doses every 6 h results in serum concentrations centered at the target range of 10–20 &mgr;g/ml. There was large interindividual variability in pharmacokinetic characteristics. There was no evidence of accumulation during the 24-h sampling period.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundAnesthesiologists routinely increase the delivered anesthetic concentration before surgical stimulation in anticipation of increased anesthetic requirement to achieve certain goals (e.g., amnesia, unconsciousness, and immobility). Electroencephalographic monitoring is one method of determining indirectly anesthetic effect on the brain. The present study investigated the effect of surgical stimuli on the concentration–response relation of desflurane-induced electroencephalographic changes.MethodsThe electroencephalographic activity was recorded from 24 female patients who received only desflurane after a single induction dose of propofol. Twelve patients served as a control group before surgical stimulation. The other 12 patients, all undergoing lower abdominal surgery, were investigated between opening and closure of the peritoneum. Desflurane vaporizer settings were randomly increased and decreased between 0.5 and 1.6 minimum alveolar concentration as long as anesthesia was considered adequate. Spectral edge frequency 95, median power frequency, and Bispectral Index were calculated. Desflurane effect-site concentrations and the concentration–effect curves for spectral edge frequency 95, median power frequency, and Bispectral Index were determined by simultaneous pharmacokinetic and pharmacodynamic modeling.ResultsSurgical stimulation shifted the desflurane concentration–electroencephalographic effect curves for spectral edge frequency 95, median power frequency, and Bispectral Index toward higher desflurane concentrations. In the unstimulated group, 2.2 ± 0.74 vol% desflurane were necessary to achieve a Bispectral Index of 50, whereas during surgery, 6.8 ± 0.98 vol% (mean ± SE) were required.ConclusionsDuring surgery, higher concentrations of the volatile anesthetic are required to achieve a desired level of cortical electrical activity and, presumably, anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundAn accepted concept in septic shock is that preload adaptation by acute left ventricular dilatation, when occurring spontaneously or with the aid of volume loading, permits maintenance of an adequate cardiac output, leading to final recovery. From a physiologic point of view, this concept appears debatable because a normal pericardium exerts a restraining action on a normal heart.MethodsDuring a 26-month period, the authors investigated, by transesophageal echocardiography, 40 patients hospitalized in their unit for an episode of septic shock. Transesophageal echocardiography was performed in the first hours after admission, proceeded by correction of any hypovolemia, and stabilization of arterial pressure by vasoactive agent infusion if necessary. Left ventricular dimensions were obtained in long- and short-axis views, permitting calculation of left ventricular ejection fraction (long axis) and fractional area contraction (short axis). Stroke index was simultaneously measured by the Doppler technique.ResultsStroke index was strongly correlated with both echocardiographic left ventricle ejection fraction (r = 0.75;P< 0.0001) and left ventricle fractional area contraction (r = 0.76;P< 0.0001), whereas it was independent of echocardiographic left ventricle diastolic dimensions.ConclusionsThe transesophageal echocardiography study was unable to confirm the reality of the concept of early preload adaptation by left ventricular dilatation in septic shock. Conversely, because left ventricular volume always remained in a normal range after correcting hypovolemia, systolic function was the unique determinant of stroke index in septic shock.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundThe relation between older age and nosocomial infection and mortality in the intensive care unit (ICU) is still a controversial issue.MethodsThe authors prospectively studied 406 patients admitted to a surgical ICU, 106 of whom were more than 75 yr old. Information concerning ICU-acquired nosocomial infections, severity of illness, therapeutic activity, and hospital outcome was collected. A Cox proportional hazard analysis was used to evaluate potential risk factors for ICU-acquired nosocomial infections, ICU, and hospital death.ResultsDuring their ICU stay, 23 elderly patients experienced 40 nosocomial infections, 28 “young” patients (< 60 yr) experienced 54 nosocomial infections, and 52 “intermediate age” patients (60–75 yr) experienced 98 nosocomial infections. Incidence density of nosocomial infections was 4.9% patient days for elderly patients, 4.7% for young patients, and 6.0% for intermediate age patients (no significance). The frequency distribution of the various microorganisms isolated was similar between the three groups. Compared with younger patients, elderly patients had a higher Acute Physiology and Chronic Health Evaluation II score and a higher ICU and hospital mortality rate. Despite a higher level of severity of illness, elderly patients had a reduction of therapeutic activity. However, Cox proportional hazard analysis showed that age more than 75 yr was not a risk factor for ICU-acquired nosocomial infection, ICU, or hospital death.ConclusionsIn patients referred to a surgical ICU after a surgical procedure, age more than 75 yr by itself does not appear to be a significant predictor of ICU-acquired nosocomial infection or mortality rate during the ICU stay. However, it appears that patients more than 60 yr have a higher incidence of nosocomial infection in ICU.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundEvery year, millions of patients receive sedatives for reduction of anxiety before surgery, but there is little objective data on the effect of this treatment on postoperative outcomes. To address this issue, the effects of benzodiazepine administration were evaluated in women undergoing abdominal surgery.MethodsPatients were randomized to receive 1 mg of oral lorazepam the night before surgery and 5 mg of intramuscular midazolam on the morning of surgery (n = 34), or to receive a placebo the night before surgery and on the morning of surgery (n = 36). Postoperative pain (Visual Analogue Scale for pain, McGill Pain Questionnaire) and analgesic consumption (patient-controlled analgesia), and clinical recovery parameters such as time to discharge from hospital were evaluated after surgery.ResultsPatient-controlled analgesia use showed a marginal main effect of treatment group (F(1,51) = 2.8;P= 0.047).Post hocanalysis demonstrated that patient-controlled analgesia consumption was significantly lower in the treatment group only during the first 4 h of patient-controlled analgesia use after surgery (P= 0.027). There were no significant group differences at any later postoperative time points (P= not significant). There were no group differences in the cumulative Percocet (Pfizer, New York, NY) consumption in the postoperative period (P= not significant). Further, self-reported postoperative pain did not differ significantly between groups at any of the time points (P= not significant). There were also no group differences with regard to any postoperative clinical recovery parameters.ConclusionsBenzodiazepines administered before surgery have minimal beneficial effects on the postoperative clinical course of women undergoing abdominal hysterectomy.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundLidocaine inhalation attenuates histamine-induced bronchospasm while evoking airway anesthesia. Because this occurs at plasma concentrations much lower than those required for intravenous lidocaine to attenuate bronchial reactivity, this effect is likely related to topical airway anesthesia and presumably independent of the specific local anesthetic used. Therefore, the authors tested the effect of dyclonine, lidocaine, and ropivacaine inhalation on histamine-induced bronchospasm in 15 volunteers with bronchial hyperreactivity.MethodsBronchial hyperreactivity was verified by an inhalational histamine challenge. Histamine challenge was repeated after inhalation of dyclonine, lidocaine, ropivacaine, or placebo on 4 different days in a randomized, double-blind fashion. Lung function, bronchial hyperreactivity to histamine, duration of local anesthesia, and lidocaine and ropivacaine plasma concentrations were measured. Statistical analyses were performed with the Friedman and Wilcoxon rank tests. Data are presented as mean ± SD.ResultsThe inhaled histamine concentration necessary for a 20% decrease of forced expiratory volume in 1 s (PC20) was 7.0 ± 5.0 mg/ml at the screening evaluation. Lidocaine and ropivacaine inhalation increased PC20significantly to 16.1 ± 12.9 and 16.5 ± 13.6 mg/ml (P= 0.007), whereas inhalation of dyclonine and saline did not (9.1 ± 8.4 and 6.1 ± 5.0 mg/ml,P= 0.7268). Furthermore, in contrast to saline and lidocaine, inhalation of both ropivacaine and dyclonine significantly decreased forced expiratory volume in 1 s from baseline (P= 0.0016 and 0.0018, respectively). The longest lasting and most intense anesthesia developed after dyclonine inhalation (48 ± 13vs.28 ± 8 [lidocaine] and 25 ± 4 min [ropivacaine]).ConclusionBoth lidocaine and the new amide local anesthetic ropivacaine significantly attenuate histamine-induced bronchospasm. In contrast, dyclonine, despite its longer lasting and more intense local anesthesia, does not alter histamine-evoked bronchoconstriction and irritates the airways. Thus, airway anesthesia alone does not necessarily attenuate bronchial hyperreactivity. Other properties of inhaled local anesthetics may be responsible for attenuation of bronchial hyperreactivity.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundHypothermia has been shown to decrease the requirement for inhaled anesthetics in animals, but information in humans is limited.MethodsThirty-three unpremedicated children with congenital left-to-right shunt heart diseases undergoing open heart surgeries were assigned to one of three groups, with nasopharyngeal temperatures at the time of skin incision of 37, 34, or 31°C. Anesthesia was induced and maintained with isoflurane in oxygen. End-tidal isoflurane concentration and nasopharyngeal temperature were kept at stable levels for at least 15 min before the skin incision. Isoflurane minimum alveolar concentration was determined by using the Dixon up-and-down approach.ResultsIsoflurane minimum alveolar concentration values were 1.69 ± 0.14%, 1.47 ± 0.10%, and 1.22 ± 0.15% (mean ± SD) at 37, 34, and 31°C, respectively.ConclusionsHypothermia decreases the isoflurane requirement in children by 5.1°C.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundGraft reperfusion in orthotopic liver transplantation is often associated with significant hemodynamic changes, including decreased systemic vascular resistance and arterial blood pressure. Vasopressive drugs are often required to maintain adequate perfusion pressure during the early postreperfusion period. The exact mechanism of this postreperfusion syndrome is unknown, but release of bradykinin, a potent vasodilatator,viathe kallikrein system may play a role. Aprotinin is a broad-spectrum inhibitor of serine proteases such as kallikrein and therefore may ameliorate the postreperfusion syndrome and reduce the need for vasopressors.MethodsIn a randomized, double-blind study, the authors compared hemodynamic variables (systemic vascular resistance, cardiac index, arterial blood pressure, mean pulmonary artery pressure, central venous pressure) and the requirement of epinephrine during transplantation in 67 patients who received either high-dose aprotinin (2 × 106kallikrein inhibitor units [KIU] at induction, continuous infusion of 1 × 106KIU/h, 1 × 106KIU before reperfusion; n = 24), regular-dose aprotinin (2 × 106KIU at induction, continuous infusion of 0.5 × 106KIU/h; n = 21), or placebo (n = 22).ResultsBaseline characteristics were similar for all three groups. Erythrocyte transfusion requirement was significantly higher in the placebo group compared with both aprotinin-treated groups. No major differences in hemodynamic variables were found between the three groups. The total amount of epinephrine (median, range) used during transplantation, however, was significantly lower in patients who received aprotinin (high dose, 20, 0–170 &mgr;g; regular dose, 30, 0–140 &mgr;g), compared with patients who received placebo (70, 0–2,970 &mgr;g;P= 0.0017). This difference was largely attributable to differences in the early postreperfusion period.ConclusionsProphylactic use of aprotinin ameliorates the postreperfusion syndrome in orthotopic liver transplantation, as reflected by a significant reduction in vasopressor requirements.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID