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

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundImprovement in patient outcome and reduced use of medical resources may result from using epidural anesthesia and analgesia as compared with general anesthesia and intravenous opioids, although the relative importance of intraoperativeversuspostoperative technique has not been studied. This prospective, double-masked, randomized clinical trial was designed to compare alternate combinations of intraoperative anesthesia and postoperative analgesia with respect to postoperative outcomes in patients undergoing surgery of the abdominal aorta.MethodsOne hundred sixty-eight patients undergoing surgery of the abdominal aorta were randomly assigned to receive either thoracic epidural anesthesia combined with a light general anesthesia or general anesthesia alone intraoperatively and either intravenous or epidural patient-controlled analgesia postoperatively (four treatment groups). Patient-controlled analgesia was continued for at least 72 h. Protocols were used to standardize perioperative medical management and to preserve masking intraoperatively and postoperatively. A uniform surveillance strategy was used for the identification of prospectively defined postoperative complications. Outcome evaluation included postoperative hospital length of stay, direct medical costs, selected postoperative morbidities, and postoperative recovery milestones.ResultsLength of stay and direct medical costs for patients surviving to discharge were similar among the four treatment groups. Postoperative outcomes were similar among the four treatment groups with respect to death, myocardial infarction, myocardial ischemia, reoperation, pneumonia, and renal failure. Epidural patient-controlled analgesia was associated with a significantly shorter time to extubation (P= 0.002). Times to intensive care unit discharge, ward admission, first bowel sounds, first flatus, tolerating clear liquids, tolerating regular diet, and independent ambulation were similar among the four treatment groups. Postoperative pain scores were also similar among the four treatment groups.ConclusionsIn patients undergoing surgery of the abdominal aorta, thoracic epidural anesthesia combined with a light general anesthesia and followed by either intravenous or epidural patient-controlled analgesia, offers no major advantage or disadvantage when compared with general anesthesia alone followed by either intravenous or epidural patient-controlled analgesia.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundThe authors evaluated the quality of clinical trials published in four anesthesia journals during the 20-yr period from 1981–2000.MethodsTrials published in four major anesthesia journals during the periods 1981–1985, 1991–1995, and the first 6 months of 2000 were grouped according to journal and year. Using random number tables, four trials were selected from all of the eligible clinical trials in each journal in each year for the periods 1981–1985 and 1991–1995, and five trials were selected from all of the trials in each journal in the first 6 months of 2000. Methods and results sections from the 160 trials from 1981–1985 and 1991–1995 were randomly ordered and distributed to three of the authors for blinded review of the quality of the study design according to 10 predetermined criteria (weighted equally, maximum score of 10): informed consent and ethics approval, eligibility criteria, sample size calculation, random allocation, method of randomization, blind assessment of outcome, adverse outcomes, statistical analysis, type I error, and type II error. After these trials were evaluated, 20 trials from the first 6 months of 2000 were randomly ordered, distributed, and evaluated as described.ResultsThe mean (± SD) analysis scores pooled for the four journals increased from 5.5 ± 1.4 in 1981–1985 to 7.0 ± 1.1 in 1991–1995 (P< 0.00001) and to 7.8 ± 1.5 in 2000. For 7 of the 10 criteria, the percentage of trials from the four journals that fulfilled the criteria increased significantly between 1981–1985 and 1991–1995. During the 20-yr period, the reporting of sample size calculation and method of randomization increased threefold to fourfold, whereas the frequency of type I statistical errors remained unchanged.ConclusionAlthough the quality of clinical trials in four major anesthesia journals has increased steadily during the past two decades, specific areas of trial methodology require further attention.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundDespite a number of studies showing that women and men respond to coronary artery bypass graft surgery differently, it is not known whether variables associated with mortality are the same for women and men. The purpose of this study was to identify variables independently associated with mortality for women undergoing coronary artery bypass graft surgery.MethodsSingle-institutional data were prospectively collected from 5,113 patients (1,558 or 30.5% women) undergoing coronary artery bypass graft surgery. The database was reviewed for patient characteristics and operative outcomes based on sex. Complications evaluated included low cardiac output syndrome (cardiac index < 2.0 l · min−1· m−2for > 8 h, regardless of treatment), stroke (new permanent global or focal motor deficits), Q-wave myocardial infarction, postoperative atrial fibrillation, and operative mortality.ResultsWomen were older than men, and they were more likely to have preexisting hypertension, diabetes, and a history of stroke. Operative mortality for women was higher than for men (3.5%vs.2.5%,P< 0.05). Compared with men, women were more likely to experience a postoperative myocardial infarction, stroke, and low cardiac output syndrome. When performing analysis on data from both sexes separately, low cardiac output syndrome, new stroke, myocardial infarction, and duration of cardiopulmonary bypass were independently associated with mortality for women and men both. Patient age was not independently associated with risk for mortality for women, but it was for men. However, when the authors combined both sexes in the logistic regression analysis, the age–sex interaction was not significant (P= 0.266), indicating that there was insufficient evidence to assert that age has a different effect on mortality for men and women.ConclusionsThese data confirm that women have higher perioperative mortality after coronary artery bypass graft surgery compared with men. A higher frequency of cardiac and neurologic complications seem to account to a large extent for the higher operative mortality for women. Factors independently associated with perioperative mortality are generally similar for women and men.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundIt is generally argued that variations in cerebral blood flow create concomitant changes in the cerebral blood volume (CBV). Because nitrous oxide (N2O) inhalation both increases cerebral blood flow and may increase intracranial pressure, it is reasonable to assume that N2O acts as a general vasodilatator in cerebral vessels both on the arterial and on the venous side. The aim of the current study was to evaluate the effect of N2O on three-dimensional regional and global CBV in humans during normocapnia and hypocapnia.MethodsNine volunteers were studied under each of four conditions: normocapnia, hypocapnia, normocapnia + 40–50% N2O, and hypocapnia + 40–50% N2O. CBV was measured after99mTc-labeling of blood with radioactive quantitative registrationviasingle photon emission computer-aided tomography scanning.ResultsGlobal CBV during normocapnia and inhalation of 50% O2was 4.25 ± 0.57% of the brain volume (4.17 ± 0.56 ml/100 g, mean ± SD) with no change during inhalation of 40–50% N2O in O2. Decreasing carbon dioxide (CO2) by 1.5 kPa (11 mmHg) without N2O inhalation and by 1.4 kPa (11 mmHg) with N2O inhalation reduced CBV significantly (F = 57,P< 0.0001), by 0.27 ± 0.10% of the brain volume per kilopascal (0.26 ± 0.10 ml · 100 g−1· kPa−1) without N2O inhalation and by 0.35 ± 0.22% of the brain volume per kilopascal (0.34 ± 0.22 ml · 100 g−1· kPa−1) during N2O inhalation (no significant difference). The amount of carbon dioxide significantly altered the regional distribution of CBV (F = 47,P< 0.0001), corresponding to a regional difference in &Dgr;CBV when CO2is changed. N2O inhalation did not significantly change the distribution of regional CBV (F = 2.4,P= 0.051) or &Dgr;CBV/&Dgr;CO2in these nine subjects.ConclusionsNitrous oxide inhalation had no effect either on CBV or on the normal CBV–CO2response in humans.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundAdequate fluid resuscitation in critically ill patients undergoing mechanical ventilation remains a difficult challenge, and diastolic and systolic right ventricular (RV) changes produced by positive airway pressure are important to consider in an individual patient with inadequate circulatory adaptation during respiratory support. We hypothesized that insufficient thoracic vena cava filling, predisposing to inspiratory collapse (zone 2 condition), may transiently affect RV outflow.MethodsWe measured beat-to-beat superior vena caval diameter and Doppler RV outflow during a routine transesophageal echocardiographic examination in 22 patients undergoing mechanical ventilation, all of whom required hemodynamic monitoring, and we calculated a collapsibility index for the superior vena cava as maximal expiratory diameter minus minimal inspiratory diameter, divided by maximal expiratory diameter.ResultsIn 15 patients (group 1), the collapsibility index was low (17 ± 7%) and was associated with a moderate inspiratory decrease in RV outflow (25 ± 17%). However, in seven patients (group 2), we observed a high collapsibility index (71 ± 7%), which was associated with a major inspiratory decrease in RV outflow (69 ± 14%) combined with a reduced pulmonary artery flow period. A rapid volume expansion, only performed on group 2, markedly and significantly reduced both the collapsibility index (15 ± 12%) and the inspiratory decrease in RV outflow (31 ± 20%).ConclusionA major inspiratory decrease in RV outflow associated with a reduced pulmonary artery flow period in a patient undergoing mechanical ventilation reflected a high collapsibility index of the thoracic vena cava, suggesting a zone 2 condition, and may be corrected by blood volume expansion.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundA decrease of 1 or 2°C in core temperature may provide protection against cerebral ischemia. However, during corporeal cooling of unanesthetized patients, the initiation of involuntary motor activity (shiver) prevents the reduction of core temperature. The authors’ laboratory previously showed that focal facial warming suppressed whole-body shiver. The aim of the current study was to determine whether the use of hand warming alone could suppress shiver in unanesthetized subjects and hence potentiate core cooling.MethodsSubjects (n = 8; healthy men) were positioned supine on a circulating water mattress (8–15°C) with a convective-air coverlet (14°C) extending from their necks to their feet. A dynamic protocol was used in which focal hand warming was used to suppress involuntary motor activity, enabling noninvasive cooling to decrease core temperatures. The following parameters were monitored: (1) heart rate; (2) blood pressure; (3) core temperature (rectal, tympanic); (4) cutaneous temperature and heat flux; (5) subjective shiver level (SSL scale 0–10) and thermal comfort index (scale 0–10); (6) metabolic data (n = 6); and (7) electromyograms.ResultsDuring cooling without hand warming, involuntary motor activity increased until it was widespread. After subjects reported whole-body shiver (SSL ≥ 7), applied hand warming, in all cases, reduced shiver levels (SSL ≤ 3), decreased electromyographic root mean square amplitudes, and allowed core temperature to decrease from 37.0 ± 0.2 to 35.9 ± 0.5°C (measured rectally).ConclusionsFocal hand warming seems to be valuable in minimizing or eliminating the need to suppress involuntary motor activity pharmacologically when it is desired to induce or maintain mild hypothermia; it may be used in conjunction with facial warming or in cases in which facial warming is contraindicated.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundPositive end-expiratory pressure (PEEP) is commonly applied to the ventilated lung to try to improve oxygenation during one-lung ventilation but is an unreliable therapy and occasionally causes arterial oxygen partial pressure (Pao2) to decrease further. The current study examined whether the effects of PEEP on oxygenation depend on the static compliance curve of the lung to which it is applied.MethodsForty-two adults undergoing thoracic surgery were studied during stable, open-chest, one-lung ventilation. Arterial blood gasses were measured during two-lung ventilation and one-lung ventilation before, during, and after the application of 5 cm H2O PEEP to the ventilated lung. The plateau end-expiratory pressure and static compliance curve of the ventilated lung were measured with and without applied PEEP, and the lower inflection point was determined from the compliance curve.ResultsMean (± SD) Pao2values, with a fraction of inspired oxygen of 1.0, were not different during one-lung ventilation before (192 ± 91 mmHg), during (190 ± 90), or after ( 205 ± 79) the addition of 5 cm H2O PEEP. The mean plateau end-expiratory pressure increased from 4.2 to 6.8 cm H2O with the application of 5 cm H2O PEEP and decreased to 4.5 cm H2O when 5 cm H2O PEEP was removed. Six patients showed a clinically useful (> 20%) increase in Pao2with 5 cm H2O PEEP, and nine patients had a greater than 20% decrease in Pao2. The change in Pao2with the application of 5 cm H2O PEEP correlated in an inverse fashion with the change in the gradient between the end-expiratory pressure and the pressure at the lower inflection point (r = 0.76). The subgroup of patients with a Pao2during two-lung ventilation that was less than the mean (365 mmHg) and an end-expiratory pressure during one-lung ventilation without applied PEEP less than the mean were more likely to have an increase in Pao2when 5 cm H2O PEEP was applied.ConclusionsThe effects of the application of external 5 cm H2O PEEP on oxygenation during one-lung ventilation correspond to individual changes in the relation between the plateau end-expiratory pressure and the inflection point of the static compliance curve. When the application of PEEP causes the end-expiratory pressure to increase from a low level toward the inflection point, oxygenation is likely to improve. Conversely, if the addition of PEEP causes an increased inflation of the ventilated lung that raises the equilibrium end-expiratory pressure beyond the inflection point, oxygenation is likely to deteriorate.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID