延迟复苏对烫伤大鼠心肝肾氧自由基生成的影响及维生素E和维生素C治疗效果评价

采用３６只肠内含５种细菌悉生的大鼠，分成伤前对照组（Ⅰ组）、早期复苏组（Ⅱ组）、延迟复苏组（Ⅲ组）和治疗组（Ⅳ组），观察了伤后８ｈ和１ｄ心、肝、肾氧自由基（ＯＦＲ）相对量（ＥＳＲ技术）及丙二醛（ＭＤＡ）含量变化。结果发现，Ⅱ、Ⅲ组大鼠心、肝、肾ＯＦＲ相对含量均增高，Ⅲ组升高更明显，各时间点较Ⅱ组均有显著差异（Ｐ＜０．０１），尤以肾脏升高最明显。Ⅳ组各脏器ＯＦＲ相对含量低于Ⅲ组（Ｐ＜０．０１）。各脏器ＭＤＡ含量与ＯＦＲ相对含量变化规律基本一致。该结果表明，延迟复苏增加烧伤后早期脏器ＯＦＲ生成，导致脂质过氧化反应加重，ＯＦＲ对肾脏的影响可能重于其它脏器。维生素Ｅ、维生素Ｃ联合治疗可有效清除脏器中ＯＦＲ，可用于延迟复苏后脏器功能保护。     

Evaluation of the influence of the aqueous phase bioconstituent environment on the F-19 T1 of perfluorocarbon blood substitute emulsions

Oxygen-sensitive F-19 magnetic resonance imaging of perfluorocarbon compounds requires that fluorocarbon T1 changes correlate with the local Po₂ and not with the composition of the surrounding aqueous phase. The influence of various bioconstituents and paramagnetic ions within the aqueous phase on the F-19 fluorocarbon phase T1 for PFC emulsions was evaluated at 0.14 and 0.66 T. T1 was measured for FC-43, perflubron, and a fluorinated surfactant. Controlled variables introduced in the aqueous phase included annex solution constituents, blood, pH changes, and Gd-DTPA. For a constant Po₂, the F-19 T1s were independent of the emulsion constituents, blood concentration, and pH. For FC-43 and perflubron, F-19 T1 was independent of the Gd-DTPA concentration, while the aqueous phase T1 decreased by more than an order of magnitude. XMO-10 (smallest emulsion particle size) showed a slight decrease in F-19 T1 with increasing Gd-DTPA concentration at 0.66 T.     

Mechanical efficiency of the left ventricle as a function of preload,afterload, and contractility

Summary We have recently shown that the mechanical efficiency of the contractile machinery of the canine left ventricle is constant at 30%–50%, independent of its loading, heart rate, and inotropic conditions. In contrast, the conventional mechanical efficiency of the ventricle is known to vary between 0 and 30%, depending on these conditions. In this study, we derived an equation for the conventional mechanical efficiency as a function of ventricular preload, afterload, and contractility, based on the constant mechanical efficiency of the contractile machinery. In deriving this equation, we fully utilized our new concept of the total mechanical energy of the left ventricle, i.e., systolic pressure-volume area, and our recent findings of the linear relationship between left ventricular oxygen consumption and the systolic pressure-volume area as well as the dependence of this relation on the ventricular inotropic state. As a result, the conventional mechanical efficiency of the left ventricle was found to change between 0 and 25% as an explicit function of these cardiodynamic and inotropic conditions. Using this function, we obtained combinations of loading and inotropic conditions to maximize the conventional mechanical efficiency of the left ventricle.     

Effect of some free radical scavengers on reperfusion induced arrhythmias in the isolated rat heart

The possible role of oxygen free radicals in the development of reperfusion arrhythmias was investigated using a 10-min period of coronary ligation followed by reperfusion in the isolated rat heart. Superoxide dismutase (5 to 20 u/ml) glutathione (10(-5) to 10(3)M) and ascorbic acid (10(-4) to 5 X 10(-4) M) when given before coronary ligation attenuated the development of reperfusion arrhythmias. Mannitol (2 X 10(-2)M) and catalase (100 and 300 u/ml) did not have any significant effect on reperfusion arrhythmias when given alone but they did potentiate the antiarrhythmic effect of superoxide dismutase. Glutathione, and a combination of superoxide dismutase, catalase and mannitol also reduced the incidence of reperfusion induced ventricular fibrillation when given just before reperfusion. By perfusing hearts with ferricytochrome C it was possible to show an increased reduction of ferricytochrome C during the first minute of reperfusion which could be prevented by the addition of superoxide dismutase. These results provide evidence that oxygen free radicals are produced and may be important in the genesis of reperfusion induced arrhythmias in the isolated rat heart.     

Intra-operative oxygen delivery in infusion volume-optimized patients undergoing laparoscopic colorectal surgery within an enhanced recovery programme: the effect of different analgesic modalities

Aim Patients undergoing major open surgery who have an indexed oxygen delivery (DO₂I) > 600 ml/min/m² have been shown to have a lower incidence of morbidity and mortality compared with those whose DO₂I is below this level. Laparoscopy and Trendelenburg positioning cause a reduction in DO₂I. We aimed to quantify the effect of the type of analgesia on DO₂I and to correlate the DO₂I achieved with the incidence of anastomotic leakage in patients undergoing laparoscopic surgery. Method Following ethical approval, patients were randomized to receive spinal anaesthesia (Group S), epidural analgesia (Group E) or intravenous morphine (Group P) followed by postoperative patient‐controlled analgesia (PCA). In addition to standard monitoring, oesophageal Doppler monitoring of the stroke volume allowed directed intravenous fluid therapy. The mean DO₂I was compared with the anastomotic leakage rate. Results Seventy‐five patients were recruited (Group S, 27; Group E, 23; Group P, 25). The mean (range) DO₂I for all patients was 490 (230‐750) ml/min/m². The analgesic modality had no effect on DO₂I. Of the 18 patients with a DO₂I of < 400 ml/min/m², four (22%) developed anastomotic leakage compared with one (%) of the 57 patients with a DO₂I of > 400 ml/min/m² (P = 0.01). Conclusion The analgesic modality used had no effect on the DO₂I achieved. Anastomotic leakage was significantly higher in patients with a DO₂I of < 400 ml/min/m². A further study assessing the outcome after raising the DO₂I with inotropes is required.     

High frequency percussive ventilation and low FiO(2)

Background

High-frequency percussive ventilation (HFPV) is an effective rescue therapy in ventilated patients with acute lung injury. High levels of inspired oxygen (FiO₂) are toxic to the lungs. The objective of this study was to review a low FiO₂ (0.25)/HFPV protocol as a protective strategy in burn patients receiving mechanical ventilation greater than 10 days.

Methods

A single-center, retrospective study in burn patients between December 2002 and May 2005 at the LAC + USC Burn Center. Demographic and physiologic data were recorded from time of admission to extubation, 4 weeks, or death.

Results

32 subjects were included in this study, 1 patient failed the protocol. 23 of 32 (72%) patients were men and mean age was 46 ± 15 years. Average TBSA burn was 30 ± 20 with 9 of 32 (28%) having >40% TBSA involved. Average burn index was 76 ± 21. 22 of 32 (69%) had inhalation injury and 23 of 32 (72%) had significant comorbidities. Average ventilator parameters included ventilator days 24 ± 12, FiO₂ 0.28 ± 0.03, PaO₂ 107 ± 15 Torr, PaCO₂ 42 ± 4 Torr, and PaO₂/FiO₂ ratio 395 ± 69. 16 of 32 (50%) patients developed pneumonia and 9 of 32 (28%) died. No patient developed ARDS, barotrauma, or died from respiratory failure. There was no association between inhalation injury and mortality in this group of patients.

Conclusion

A low FiO₂/HFPV protocol is a safe and effective way to ventilate critically ill burn patients. Reducing the oxidative stress of high inspired oxygen levels may improve outcome.     

Oxygen dynamics at paraspinal muscles during exertion using near-infrared spectroscopy in patients with degenerative lumbar scoliosis

 Oxygen dynamics were measured in both sides of the paraspinal muscles of patients with degenerative lumbar scoliosis. The objective was to investigate the extent of stress by measuring the changes in oxygenation and blood flow volume using near-infrared spectroscopy. There were 44 patients with degenerative lumbar scoliosis (7 men, 37 women) and 11 controls with no scoliosis (2 men, 9 women). The measured recovery time for deoxyhemoglobin indicated the recovery from energy deficit after exercise. The average recovery time of the 11 control subjects was 2.4 ± 0.7 s on the right and 2.4 ± 0.8 s on the left. Among the 44 patients the average recovery time was 3.8 ± 1.8 s on the convex side and 2.1 ± 1.1 s on the concave side. There was a significant difference between the two groups. The recovery time on the concave side in patients was faster than that on the convex side. The results of the current study support the theory that stretching the muscles at the convex side results in chronic increases in the intramuscular compartment and reduced muscular blood flow. Received: May 23, 2002 / Accepted: October 29, 2002 Offprint requests to: M. Miyake, Department of Orthopaedic Surgery, Eiko Hospital, 1381 Takuma, Takuma-cho, Mitoyo-gun, Kagawa 769-1101, Japan     

High alcohol intake in deceased donors has no effect on pancreas graft survival: a registry analysis

Outcomes of pancreas transplantation from donors with high alcohol consumption are poorly described. The UK Transplant Registry was used to determine whether donor alcohol intake influenced pancreas survival in simultaneous pancreas–kidney (SPK) transplants performed between 2006 and 2012 (n = 770). Recipients were stratified by donor alcohol intake: group I (n = 122)—high recent alcohol intake (>21 or >14 units of alcohol/week in males or females, respectively) or previous alcohol abuse and group II (n = 648)—low/unknown current intake and no previous alcohol abuse. Median current alcohol intake was higher in group I than group II: 36.3 vs. 10 units/week; P < 0.001. One‐ and five‐year pancreas graft survivals were 88.5% and 73.6% in group I, and 87% and 74.9% in group II. There was no difference in unadjusted graft survival between groups I and II (P = 0.76), and no difference between group II and a subgroup of group I with a donor history of alcohol abuse and high current intake (P = 0.26), or from donors with current alcohol consumption of >50 units/week (P = 0.41). Pancreas donors with past alcohol abuse or current high intake are common, and graft outcomes appear to be acceptable. This analysis suggests that high donor alcohol intake, by itself, should not exclude consideration of pancreas transplantation.     

Optimizing the use of liposomal bupivacaine in shoulder arthroplasty

BackgroundShoulder arthroplasty (SA) is the fastest growing joint replacement surgery in the United States, and it has been estimated that postoperative pain management is not adequately controlled in up to 80% of patients. Liposomal bupivacaine (LB) has been included as part of the multimodal pain management that has shown promise in reducing pain, narcotic consumption, and hospital length of stay in SAs, but there has been some controversy regarding its efficacy in the literature. This may be due to lack of standardization across studies in the utilization of LB or the lack of efficacy of local LB infiltration. The purpose of this study was to identify whether there is an optimal dilution of LB required for maximal analgesia after SA in order to direct future literature and increase the strength of evidence for recommendations in clinical practice.MethodsA retrospective review of prospectively collected data was conducted with patients undergoing primary SA categorized into 40 mL, 60 mL, or 80 mL dilutions of 20 mg of LB with 0.9% normal saline. Patient-reported pain scores and opioid consumption were collected at days 1, 3, 7, and 30 postoperatively. Dependence rates were reported and defined as three months of continuous opioid use. Opioid consumption was calculated using total morphine equivalents (TME), and an analysis of variance was performed to compare outcomes between groups.ResultsSeventy-four patients were identified and divided into one of three groups based on the dilution of LB received intraoperatively. There were significant differences in pain scores between the groups on day 7 postoperatively with the 80 mL group having significantly lowest pain scores (P = .012). No significant difference in opioid consumption was found between the groups during any time point. There was a trend toward fewer opioids over the study period in the 80 mL group relative to other groups. Overall, all dilution groups resulted in low TME and postoperative pain after the 30-day study period.ConclusionAll three dilution groups achieved excellent pain control and minimal opioid usage following SA. The 80 mL dilution group showed lower pain scores at day 7 postoperatively and trended toward less opioid consumption in the first 30 days. Our study suggests that, overall, orthopedic surgeons can consider using all three LB dilutions as an effective and safe option for pain management after an SA.     

肝脏缺血-再灌注损伤的机制探讨

肝脏缺血-再灌注损伤包括两个不同阶段:早期发生在再灌注2～4 h内,主要由增多的氧自由基产物所介导;晚期发生于再灌注后6 h或更久,主要由于炎症反应所致,并导致肝脏的进一步损害.肝脏的肝脏缺血-再灌注损伤是一个复杂的、多因素的过程.本综述回顾了当前对肝脏缺血-再灌注损伤的理解及研究进展,分别从微循环水平、细胞水平、分子水平阐述其机制.