Posterolateral spondylodesis using bioactive glass S53P4 and autogenous bone in instrumented unstable lumbar spine burst fractures. A prospective 10-year follow-up study.

BACKGROUND AND AIMS: A prospective long-term follow-up study of bioactive glass (BAG)-S53P4 and autogenous bone (AB) used as bone graft substitutes for posterolateral spondylodesis in treatment of unstable lumbar spine burst fractures during 1996-1998 was conducted. MATERIAL AND METHODS: The lumbar fractures were fixed using posterior USS instrumentation. BAG was implanted on the left side of the fusion-bed and AB on the right side. The operative outcome was evaluated on X-rays and CT scans, and a clinical examination was also performed. RESULTS: The Oswestry score was excellent, and the mean pain score 1. The mean compression rate of the injured vertebral body was 25%. A solid bony fusion was seen on CT scans on the AB side in all patients and on the BAG side in five patients, and a partial fusion in five patients, resulting in a total fusion-rate of 71% of all fused segments in the BAG group. CONCLUSIONS: Our long-term results show that BAG-S54P4 bone graft material is safe to be used as a bone graft extender in spine surgery.

Bioactive glass S53P4 and autograft bone in treatment of depressed tibial plateau fractures - a prospective randomized 11-year follow-up.

The clinical and radiological outcomes of bioactive glass (BAG)-S53P4 and autograft bone (AB) used as bone-graft substitutes in depressed tibial plateau fractures were evaluated in a prospective randomized 11-year follow-up study. All patients (n = 29) had sustained tibial plateau fractures with a joint-line depression of >3 mm. Fifteen patients (5 patients the BAG group, 10 patients in the AB group) participated in this long-term follow-up. X-rays were taken preoperatively, postoperatively, and at the long-term follow-up, and computed tomography (CT) scans were made at the long-term follow-up for evaluation of the bone substitute, osteoarthritis, the tibial-femoral angle, and deviation of mechanical axes. No material-dependent adverse effects were seen in any patient. The means of the articular surface depression on X-rays at the long-term follow-up were 1.4 mm (range: 0-2 mm) in the BAG group and 1.4 mm (range: 0-4 mm) in the AB group, and on CT scans the means were 2.2 mm (range: 2-3 mm), and 2.1 mm (range: 0-3), respectively. No significant difference in the tibial-femoral angle or deviation of mechanical axes was observed between the two groups. BAG-S53P4 can be used as a bone substitute in depressed lateral tibial plateau fractures with good functional and radiological long-term results.

Bioactive glass S53P4 as bone graft substitute in treatment of osteomyelitis.

Bioactive glass (BAG)-S53P4 is an osteoconductive bone substitute with proven antibacterial and bone bonding properties. In a multicentre study 11 patients with verified chronic osteomyelitis in the lower extremity and the spine were treated with BAG-S53P4 as a bone substitute. The cavitary bone defect and the surrounding of a spinal implant were filled with BAG-S53P4. The most common pathogen causing the infection was Staphylococcus aureus. The mean follow-up was 24 months (range 10-38). BAG-S53P4 was well tolerated. Nine patients healed without complications. One patient who achieved good bone formation sustained a superficial wound infection due to vascular problems in the muscle flap, and one patient had an infection due to a deep haematoma. This study shows that BAG-S53P4 is a good and well-tolerated bone substitute, and can be used in treatment of osteomyelitis with good primary results.

The long-term results of Lubinus interplanta hemiarthroplasty in 228 acute femoral neck fractures. A retrospective six-year follow-up.

BACKGROUND AND AIMS: We retrospectively studied survival of patients treated with Lubinus interplanta (IP) semiendoprosthesis in acute hip fracture. MATERIALS AND METHODS: The long-term results of Lubinus interplanta (IP) hemiarthroplasty in 228 acute medial fractures of the femoral neck in 222 patients were reviewed. RESULTS AND CONCLUSIONS: The mean age of the patients was 80.3 years. The mean duration of post-operative follow-up was 6.3 years (range 5-8 years). There were 12 reoperations (5.3%), of which 8 were revisions (3.5%). Dislocation rate was 3.5%. Survival was 93% at three years and 88% at six years (Kaplan-Meier-survival analysis). CONCLUSIONS: These results surpass those previously published after Thompson and Moore hemiarthroplasties. The Lubinus prosthesis has a greater CCD (caput,collum, diaphyse) angle and a longer stem compared to Thompson and Moore implants. The need for resection of calcar cortex is also limited. These biomechanical facts may explain the good long-term results of Lubinus hemiarthroplasty.

Central hemodynamics during reamed intramedullary nailing of unilateral tibial fractures.

BACKGROUND: Intramedullary nailing of a long-bone fracture results in intravasation of bone marrow contents into the right atrium and pulmonary vascular bed and, therefore, may alter cardiac and pulmonary hemodynamics. METHODS: Central hemodynamic changes were recorded in 12 healthy adults with a unilateral simple tibial fracture undergoing intramedullary nailing. The patients were cannulated with a pulmonary artery catheter. Reamed intramedullary nailing was performed during general anesthesia. Preoperative and immediate postoperative hemodynamic variables were compared and intraoperative changes studied. RESULTS: During the operation, the right ventricular preload as represented by central venous pressure and the right ventricular afterload as presented by mean pulmonary arterial pressure increased significantly. Preoperative and postoperative arterial oxygen tension values demonstrated hypoxia. Abnormal pulmonary shunting and increased oxygen consumption were observed as well. CONCLUSION: Changes in cardiac and pulmonary hemodynamics are already present after the trauma and before the reamed intramedullary nailing procedure.

Central hemodynamic changes in experimental muscle crush injury in pigs.

To investigate central and pulmonary hemodynamics in a standardized normovolemic experimental muscle injury model, 8 anesthetized and mechanically ventilated test pigs were intracavally infused with 100 ml of autologous muscle extract over a period of 100 min; 8 control pigs received Ringer's solution. The cardiac index decreased 20% and the heart rate decreased 10% within 30 min of starting the infusion in the muscle extract group and remained depressed. Mean arterial pressure increased significantly in both groups. The pulmonary capillary wedge pressure and central venous pressure remained relatively unchanged during the 5-hour study. A 2-fold increase in mean pulmonary arterial pressure and a nearly 4-fold increase in the pulmonary vascular resistance index was seen in the muscle extract infusion group, which however returned to normal. Arterial hemoglobin concentration and systemic vascular resistance index remained fairly stationary in both groups. Immediate significant decreases in both arterial oxygen saturation and arterial oxygen tension were observed in the muscle extract group, however both variables recovered towards the end of the experiment. A slight increase in arterial blood pH value was noted during the experiment. In conclusion, autologous muscle extract infusion causes decreases in heart rate and cardiac index, as well as a significant increase in pulmonary vascular tone and systemic hypoxemia, emphasizing the detrimental effects of skeletal muscle injury following severe trauma.

The effect of unreamed and reamed intramedullary nailing on the urinary excretion of prostacyclin and thromboxane A2 metabolites in patients with tibial shaft fractures.

OBJECTIVE: To compare the effects of unreamed and reamed intramedullary nailing on the systemic production of prostacyclin and thromboxane A2 as assessed, respectively, by determinations of urinary 2,3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxane B2 excretion. METHODS: Ten otherwise healthy patients with closed and simple tibial shaft fractures were treated with unreamed intramedullary nailing, and 10 otherwise healthy patients with closed and simple tibial shaft fractures were treated with reamed intramedullary nailing. Urine was collected preoperatively and during the next 5 postoperative days. The samples were stored at -70 degrees C until assayed at the end of the study. RESULTS: In the unreamed group, urinary 2,3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxane B2 excretion remained stable and at a significantly lower levels compared with the reamed group during the entire study period (p < 0.021). In the reamed group, the alteration in urinary 2,3-dinor-6-ketoprostaglandin F1alpha excretion preoperatively and on the first postoperative day was nearly significant (p=0.075), and the increase in urinary 11-dehydrothromboxane B2 excretion was significant (p=0.020). The proportional increase compared with baseline, however, was 1.6 times greater for 11-dehydrothromboxane B2 than for 2,3-dinor-6-ketoprostaglandin F1alpha. CONCLUSION: Only reamed intramedullary nailing elevates urinary 2,3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxane B2 concentrations and their ratio (thromboxane A2/prostacyclin production) in patients with simple tibial shaft fractures.

Effects of hyperbaric oxygen therapy on perfusion parameters and transcutaneous oxygen measurements in patients with intramedullary nailed tibial shaft fractures.

We evaluated the effect of hyperbaric oxygen (HBO2) therapy on tibialis posterior (TPA), dorsalis pedis (DPA), and sum (TPA + DPA) arterial peak signals, as well as transcutaneous oxygen (PtcO2) tension and leg skin temperature (T) after intramedullary nailing of tibial shaft fractures. Twenty consecutive patients with closed and simple tibial shaft fractures treated with reamed intramedullary nailing were assigned randomly to HBO2 or control groups. HBO2 therapy was given postoperatively at 2.5 atm abs pressure for 90 min daily for a total of five treatments. The first HBO2 therapy was given 1 h after the operation. In both groups, measurements were performed preoperatively, 30 min and 6 h postoperatively, and on the following 5 days. There was a statistically significant improvement in TPA values in the nailed legs in the HBO2 treatment group after the first postoperative day, and these values remained at a significantly higher level until the end of the study when compared to the nailed legs in the control group. Further, there was a statistically significant improvement in PtcO2 values in the nailed legs in the HBO2 group after the third HBO2 treatment. However, there were no statistically significant differences in DPA and TPA + DPA values within or between the nailed legs in HBO2 and control groups. HBO2 therapy seemed to decrease the skin temperature of the nailed legs, but this alteration was not statistically significant. In addition to the clearly documented advantages in the management of crush injuries and compartment syndromes, HBO2 therapy has a positive effect on the perfusion parameter (TPA) and PtcO2 in patients with low energy, intramedullary nailed simple tibial shaft fractures. The improvement in TPA and PtcO2 values may result from the vasoconstrictive and edema reductive effect on HBO2 with concomitant inhibition of inflammatory reactions with slight cooling.

Tissue perfusion after intramedullary nailing of tibial shaft fracture.

BACKGROUNDS AND AIMS: To measure noninvasively the effect of circulative changes caused by fracture and intramedullary nailing on tibialis posterior (TPA), dorsalis pedis (DPA) and sum (TPA + DPA) arterial peak signals, transcutaneous oxygen tension (PtcO2) as well as local skin temperature (T) in patients with tibial shaft fractures. PATIENTS, MATERIAL AND METHODS: A total of thirty tibias consisting of ten closed, reamed, intramedullary nailed simple tibial shaft fractures (Type AO A), ten contralateral tibias and as controls, ten intact tibias of healthy volunteers. The measurements took place one day before and immediately after nailing, six hours later and during five days postoperatively. The values were compared to those of contralateral legs and to control legs. RESULTS: In the nailed legs the mean TPA and PtcO2 remained at a significantly lower level compared to the contralateral legs throughout the study (p < 0.003 in both cases). However, the alterations in DPA and TPA + DPA were not statistically significant. Additionally, skin temperature on the fracture site was averagely 3 degrees C warmer than that of the contralaterals (p < 0.001). All the measured parameters were statistically significantly higher in control legs compared to contralateral legs. There were no statistically significant differences between pre- and postoperative values in any measured parameters. CONCLUSION: The changes in the local tissue perfusion variables measured in the present study reflect rather the injury mechanism itself than the effect of reaming and intramedullary nailing in simple tibial fractures. Additionally, arterial circulation was reduced in the contralateral legs.

Leg tissue perfusion in simple tibial shaft fractures treated with unreamed and reamed nailing.

BACKGROUND: To compare the effects of unreamed and reamed intramedullary nailing on tibialis posterior, dorsalis pedis, and sum (tibialis posterior plus dorsalis pedis) distal arterial peak pulses. Additionally, leg skin temperature and transcutaneous oxygen tension were measured in patients with low energy, closed tibial shaft fractures. METHODS: The patients were randomized to unreamed and reamed groups, and intramedullary nailing without or with reaming was performed under spinal anesthesia. The measurements were carried out before the operation and on 5 postoperative days. RESULTS: In the unreamed group, the only significant difference between contralateral and nailed legs was in raised leg skin temperature (p = 0.0001). In the reamed group, tibialis posterior distal arterial peak pulses and transcutaneous oxygen tension remained at a significantly lower level and leg skin temperature at a significantly higher level, respectively, in the nailed legs after the operation when compared with contralateral legs (p = 0.0026, p = 0.0001, and p = 0.0001, respectively). There were no statistical differences between preoperative and postoperative values in the measured parameters in both groups. Additionally, there were no intergroup changes in the measured parameters in the injured legs. CONCLUSION: The present study suggests that altered distal arterial pulsations, decreased transcutaneous oxymetry values, and thermal reaction are not due to differences in nailing method but caused by a manifestation of the trauma mechanism of the tibial shaft fracture. The potentially negative effects of reaming to soft tissue perfusion parameters could not be established.

Experimental fat embolism induces urine 2,3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxane B2 excretion in pigs.

OBJECTIVE: To evaluate the in vivo production of prostacyclin and thromboxane A2 during the initial phase of experimental fat embolism as assessed, respectively, by determinations of urine 2,3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxane B2 excretion. DESIGN: Randomized, controlled trial. SETTING: Animal laboratory. SUBJECTS: Twenty seven domestic pigs, weighing 24 to 31 kg. INTERVENTIONS: All pigs were anesthetized and mechanically ventilated during the experiment. Eighteen pigs were subjected to an intracaval infusion of 10% allogeneic bone marrow suspension at a dose of 100 mg/kg over 5 mins. Nine pigs received only bone marrow suspension (fat embolism group). Nine pigs were given an intravenous bolus of aspirin (300 mg) 1 hr before the bone marrow suspension infusion. After the induction of fat embolism, intravenous aspirin was administered at a dose of 150 mg/hr for 2 hrs (aspirin-treated group). Nine pigs were infused with saline (control group). MEASUREMENTS AND MAIN RESULTS: In the fat embolism group, cardiac index decreased within 30 mins, while mean arterial pressure remained unchanged. Central venous pressure and pulmonary artery occlusion pressure remained relatively stable over time in the animals with fat embolism. Mean pulmonary arterial pressure and pulmonary vascular resistance increased immediately after the bone marrow suspension infusion from 23 +/- 0.8 (SEM) to 34 +/- 1.3 mm Hg and from 305 +/- 28 to 585 +/- 45 dyne x sec/cm5, respectively; these variables remained increased throughout the study period. Simultaneously, pulmonary shunt in the fat embolism group increased persistently from the baseline of 12.3 +/- 2.8%, and reached its maximum of 26.1 +/- 4.8% at the end of the experiment. Instant and gradual decreases in PaO2 (from 95 +/- 4 to 67 +/- 5 torr [12.6 +/- 0.5 to 8.9 +/- 0.7 kPa]), hemoglobin oxygen saturation (from 97.2 +/- 0.4 to 91.8 +/- 1.8%), and oxygen delivery (from 16.3 +/- 1.0 to 12.6 +/- 0.4 mL/min/kg) were observed in the fat embolism group. In the bone marrow suspension-infused animals, urine 2,3-dinor-6-ketoprostaglandin F1alpha excretion increased transiently from 451 +/- 63 up to 1466 +/- 499 pg/micromol creatinine, while urine 11-dehydrothromboxane B2 excretion increased transiently from 385 +/- 36 up to 2307 +/- 685 pg/micromol creatinine. In the aspirin-treated animals, urinary excretion of these prostanoid metabolites was reduced by 81% and 88%, respectively. The changes in mean pulmonary arterial pressure and PaO2 were ameliorated, and the alterations in pulmonary shunt and SaO2 were abolished in the animals with aspirin treatment. CONCLUSIONS: Pulmonary hypertension, increased pulmonary vascular tone, and increased pulmonary shunt are hallmarks of the present fat embolism model. These hemodynamic responses may, at least partly, be related to the changed balance between prostacyclin and thromboxane A2 production.

Catalytic activity of phospholipase A2 in serum in experimental fat embolism in pigs.

OBJECTIVE: To investigate the catalytic activity of phospholipase A2 in serum during the early phase of experimental fat embolism. DESIGN: Randomised controlled experimental study. SETTING: Animal laboratory, Finland. SUBJECTS: 18 domestic pigs weighing 25-31 kg. INTERVENTIONS: Allogeneic bone marrow suspension at a dose of 100 mg/kg was infused intracavally in 9 anaesthetised, mechanically ventilated, and haemodynamically monitored pigs; 9 control pigs received saline. MAIN OUTCOME MEASURES: Central haemodynamics, blood gases, catalytic activity of phospholipase A2. RESULTS: In the fat embolism group, there were significant increases in mean pulmonary arterial pressure (p < 0.001), pulmonary vascular resistance (p < 0.001) and pulmonary shunting (p < 0.05) and simultaneously, systemic oxygenation was significantly impaired. The animals with fat embolism developed gradual fever and leucocytosis, whereas the catalytic activity of phospholipase A2 remained relatively unchanged. CONCLUSION: In this experimental model the measurement of serum phospholipase A2 activity does not provide a useful tool for the early detection of experimental fat embolism.

Group II phospholipase A2 in serum after knee surgery and intramedullary nailing of tibial shaft fracture.

This prospective study investigates the effect of injury and surgery of cartilage and bone on serum group II phospholipase A2 (PLA2-II) and C-reactive protein (CRP) levels. Serum concentrations of PLA2-II and CRP were measured before and after the operation in nine patients with closed tibial shaft fractures treated by nailing, 11 patients with fractures of lateral tibial plateau treated by bone grafting, and 19 patients with ruptured anterior cruciate ligament treated by reconstruction. The postoperative PLA2-II and CRP values were statistically significantly higher than the pre-operative values in the tibial plateau fracture and ligament rupture groups, whereas the increase in the PLA2-II values in the tibial fracture group was not statistically significant. The highest values of both parameters were found on the second postoperative day. The changes in the PLA2-II and CRP values were parallel in the lateral condyle fracture and in anterior cruciate ligament rupture groups. PLA2-II behaves as an acute phase reactant in the serum of patients undergoing acute and elective knee surgery.

Spondylodesis in the treatment of segmental instability of the lumbar spine with special reference to clinically verified instability.

We analysed the outcome of 42 consecutive patients suffering from low back pain and segmental instability of the lumbar spine who underwent spondylodesis with transpedicular fixation. There were 29 (69%) females and 13 (31%) males with a mean age of 47 +/- 9 years (range 23 to 66 years). The presence of clinically verified instability was a basic requirement for operative treatment, with at least one clinical sign of instability positive in all patients. Radiological signs of instability were detected in only 74% of the patients. After a postoperative follow-up of one year, lumbar fusion was found in 38 (90%) patients. The fusion was classified as complete in 18 (43%) and as partial in 20 (47%) patients. No fusion there was detected in 4 (10%) patients. Low back pain was completely abolished in 19 (45%) and markedly diminished in 15 (36%) patients in (17%) patients, low back pain had remained unchanged and become worse in 1 (2%) patient. Clinical signs and symptoms of instability were still detected in 10 (24%) patients. As compared to the pre-operative situation, the decrease in clinical instability was statistically significant (p = 0.02). Moreover, a significant correlation was observed between the persistence of clinically verified instability and a poor postoperative outcome in daily activities. Of all patients, 17 (40%) returned to work during the period of follow up. Based on the good outcome of our patients, the results of this study show that clinical signs and symptoms of instability can be successfully used as selection criteria for lumbar spondylodesis.

Plasma levels of atrial natriuretic peptide and endothelin-1 in experimental fat embolism.

In order to understand the role of vasoactive peptides in fat embolism, arterial plasma atrial natriuretic peptide (ANP) and endothelin-1 concentrations were investigated in an experimental study. Nine anesthetized and mechanically ventilated pigs received an intracaval infusion of allogeneic bone marrow suspension at a dose of 100 mg/kg (fat embolism group); 9 control pigs received saline. The observation period was 5 h. In the fat embolism group, cardiac index and heart rate decreased within 30 min, whereas mean arterial pressure remained stationary. Pulmonary capillary wedge pressure rose transiently and central venous pressure rose slightly in time, while mean pulmonary arterial pressure, pulmonary vascular resistance and pulmonary shunt increased immediately and persistently after the bone marrow suspension infusion. Simultaneously, arterial oxygen tension and arterial hemoglobin oxygen saturation decreased markedly. Arterial plasma ANP and endothelin-1 concentrations remained stable in the fat embolism animals, whereas in the controls ANP and endothelin-1 levels decreased at 3 and 5 h. Arterial epinephrine concentrations were stable in animals receiving bone marrow suspension, while in the controls arterial epinephrine concentrations decreased towards the end of the experiment. Arterial norepinephrine concentrations remained unchanged in both groups. To conclude, impaired pulmonary function and consequent systemic hypoxemia distinguish the present fat embolism model. Unchanged arterial ANP and endothelin-1 concentrations in the fat embolism group suggest that these circulating vasoactive hormones have a minor impact on the pathogenesis of the current experimental fat embolism.

Splanchnic and peripheral tissue perfusion in experimental fat embolism.

OBJECTIVE: To investigate the acute effects of experimental fat embolism on splanchnic and peripheral perfusion and oxygenation in pigs. DESIGN: Randomized, controlled trial. SETTING: Animal laboratory. SUBJECTS: Eighteen domestic pigs, weighing 25 to 31 kg. INTERVENTIONS: The 18 pigs were randomized to either the fat embolism or control groups. Nine anesthetized and mechanically ventilated pigs were intracavally infused with a 10% allogeneic bone marrow suspension at a dose of 100 mg/kg over 5 mins (the fat embolism group); nine control pigs received normal saline in the same volume and speed (control group). MEASUREMENTS AND MAIN RESULTS: Mean pulmonary arterial pressure, pulmonary vascular resistance, and pulmonary shunt increased, and PaO2 decreased immediately after the bone marrow suspension infusion. In the fat embolism animals, oxygen delivery decreased, oxygen content difference widened, and total oxygen consumption remained high, indicating enhanced oxygen extraction. Further, superior mesenteric artery blood flow and mesenteric oxygen delivery decreased, while intramucosal pH in the small bowel was stable. Subcutaneous PO2 decreased in both groups, whereas transcutaneous PO2 decreased only in the animals receiving bone marrow suspension. Skin red cell flux showed no significant changes. CONCLUSIONS: The present model of fat embolism results in significant impairment in systemic oxygenation. Despite this fact, the intestinal oxygenation remains unaffected probably due to sufficient compensatory mechanisms. Transcutaneous PO2 measurements may provide a useful index for early detection of fat embolism.

Effects of experimental fat embolism on central hemodynamics and oxygenation in pigs.

Nine anesthetized and mechanically ventilated test pigs were intracavally infused with a 10% allogeneic bone marrows suspension at a dose of 100 mg/kg over 5 min; 9 control pigs received saline. The cardiac index decreased slightly in the fat embolism animals. Left ventricular stroke work remained unchanged in both groups, whereas right ventricular stroke work rose in the fat embolism animals. Mean arterial pressure remained stationary in the test group but rose in the controls. Pulmonary capillary wedge pressure and central venous pressure rose slightly in the test group. After infusion of the bone marrow suspension, mean pulmonary arterial pressure, pulmonary vascular resistance, pulmonary shunt and alveoloarterial oxygen tension difference increased immediately and remained elevated throughout the study period. Simultaneously, arterial and mixed venous oxygen tension and hemoglobin oxygen saturation decreased. Arterial carbon dioxide tension and hematocrit remained stationary. The fat embolism animals developed gradual fever. In conclusion, increased mean pulmonary arterial pressure, pulmonary vascular resistance, pulmonary shunt and alveoloarterial oxygen tension difference proved to be useful early indicators of experimental fat embolism.

Renal carnitine concentration decreases in endotoxic dogs.

BACKGROUND AND METHODS: Renal cortical and serum carnitine concentrations were studied in seven anesthetized beagle dogs in which acute circulatory collapse was induced by an iv injection of Escherichia coli endotoxin, 0.5 mg/kg given over 15 mins. Four controls received normal saline. RESULTS: The endotoxin injection resulted in cardiac depression, renal hypoperfusion, acidosis with a decrease in urinary output, and hematuria. Arterial and renal venous free carnitine concentrations increased significantly in endotoxemia during the 5-hr experiment, but remained low and unchanged in the controls. Circulating acyl-carnitine concentrations underwent no essential changes in either group. Total, free, and acyl-carnitine concentrations decreased in endotoxic renal tissue. CONCLUSIONS: These data suggest that endotoxemia decreases carnitine concentrations in the renal cortex, but increases free carnitine concentrations in the circulation.

Renal perfusion and metabolism in experimental endotoxin shock.

Central and renal hemodynamics, renal oxygenation, renal uptake of glucose, lactate, fats, renal carnitine metabolism, arterial atrial natriuretic factor (ANF) and catecholamine release were studied in sixteen adult beagle dogs during pentobarbital anesthesia. Renal cortical oxygen tension was recorded by means of a Silastic tonometer. Twelve animals underwent acute circulatory shock induced by intravenous Escherichia coli endotoxin 0.5 mg/kg. Four control dogs received normal saline. The endotoxin infusion resulted in decreased cardiac function, renal blood flow and renal cortical PO2. The renal venous PO2 increased during the experiment. Arterial and renal venous glucose concentrations increased transiently during endotoxemia. Circulating lactate concentrations increased significantly whereas the arteriovenous lactate difference remained almost unchanged. Renal uptake of lactate and glucose were not influenced during the moderate renal hypoperfusion caused by endotoxin. Arterial free fatty acid (FFA) concentrations increased significantly 2 hours after onset of the endotoxin infusion whereas renal venous FFA levels remained rather stationary. The renal uptake of FFA increased with increasing arterial FFA concentrations. Circulating free carnitine concentrations increased significantly in endotoxin shock. Blood acyl-carnitine concentrations remained essentially unchanged. Carnitine concentrations declined significantly in endotoxic renal tissue. The arterial concentrations of ANF, epinephrine, norepinephrine and the norepinephrine metabolite 3,4-dihydroxyphenylglycol (DHPG) increased in plasma during early endotoxemia. The levels of these hormones remained very low and constant in the controls. To summarize, endotoxin injection resulted in impaired renal perfusion and oxygenation, increased uptake of free fatty acids and unchanged uptake of glucose, lactate, glycerol and triglycerides. Decreased renal carnitine concentrations were observed. Arterial plasma concentrations of ANF and catecholamines increased in endotoxin shock.

Renal uptake of fats and glycerol in endotoxin shock in dogs.

Circulatory changes and renal uptake of free fatty acids (FFA), glycerol and triglycerides were studied in ten adult beagle dogs during pentobarbital anesthesia. Six dogs were injected intravenously with E. coli endotoxin 0.5 mg/kg over 15 min and four control dogs received saline. Cardiac depression, hypotension, renal hypoperfusion and acidosis resulted in endotoxin shock. Arterial FFA concentrations increased significantly 2 hours after onset of shock whereas renal venous FFA levels remained rather stationary during the 5-hour study. Arterial and renal venous glycerol levels increased during the first two hours and decreased thereafter. Unchanged triglyceride levels were observed in endotoxin shock. The renal uptake of FFA increased with increasing arterial FFA concentrations. Net renal uptake of glycerol and triglycerides were observed as well. Blood concentrations and renal uptake of fats and glycerol remained relatively stationary in the control animals through the observation period. These data suggest renal ability to consume FFA, glycerol and triglycerides during endotoxin shock.