Aerosol therapy with thiamphenicol glycinate: a retrospective study on efficacy and safety in a group of sixty-six oncological patients.

The purpose of this paper is to present the effectiveness of aerosol administration of TG in a group of oncological patients. Thiamphenicol is an antimicrobial agent active in the treatment of infection of different etiology and localisation due to its broad spectrum of antimicrobial activity as well as its pharmacokinetic properties. The data of the retrospective study analysis of the activity of TG, administered to oncological patients affected by infections of the respiratory tract, showed that TG administered alone or in association with other antibiotics was globally effective in more than 95% of patients. These positive results were obtained in immunologically compromised patients. The therapeutic advantages of using TG are: ease of use - aerosol therapy permits good local action; tolerability - no adverse reaction or intolerance; the possibility of using it in an ideal association with other antibiotics to combat the infectious pathology.

From less to maximally invasiveness in cervical spine surgery: A "nightmare" case who deserve consideration.

INTRODUCTION: Multilevel cervical myelopathy without surgical treatment is generally poor in the neurological deficit without surgical decompression. The two main surgical strategies used for the treatment of multilevel cervical myelopathy are anterior decompression via anterior corpectomy or posterior decompression via laminctomy/laminoplasty. PRESENTATION OF CASE: We present the case of a 62 year-old lady, harboring rheumatoid artritis (RA) with gait disturbances, pain, and weakness in both arms. A C5 and C6 somatectomy, C4-C7 discectomy and, instrumentation and fusion with telescopic distractor "piston like", anterior plate and expandable screws were performed. Two days later the patient complained dysfagia, and a cervical X-ray showed hardware dislocation. So a C4 somatectomy, telescopic extension of the construct up to C3 with expandible screws was performed. After one week the patient complained again soft dysfagia. New cervical X-ray showed the pull out of the cranial screws (C3). So the third surgery "one stage combined" an anterior decompression with fusion along with posterior instrumentation, and fusion was performed. DISCUSSION: There is a considerable controversy over which surgical approach will receive the best clinical outcome for the minimum cost in the compressive cervical myelopathy. However, the most important factors in patient selection for a particular procedure are the clinical symptoms and the radiographic alignment of the spine. the goals of surgery for cervical multilevel stenosis include the restoration of height, alignment, and stability. CONCLUSION: We stress the importance of a careful patients selection, and invocated still the importance for 360° cervical fixation.

Chronic subthalamic nucleus stimulation reduces medication requirements in Parkinson's disease.

OBJECTIVE: To reduce antiparkinsonian medication in parkinsonian patients with bilateral high frequency subthalamic nucleus (STN) stimulation. BACKGROUND: Parkinsonian syndromes are characterized by hyperactivity of the STN. Preliminary data indicate that functional inactivation of the STN may reduce the requirement for dopaminergic therapy in PD. METHODS: Bilateral quadripolar leads were implanted stereotactically in the STN of seven patients with advanced PD (mean age, 57.4 years; mean disease duration, 15.4 years). High-frequency stimulation was applied for 24 hours a day. Following implantation, antiparkinsonian medication was reduced to the minimum possible and stimulation was gradually increased. The patients were evaluated in the practically defined "off" and "on" conditions using the Unified Parkinson's Disease Rating Scale (UPDRS) and the Schwab & England scale. The average follow-up was 16.3+/-7.6 months. A battery of neuropsychological tests was applied before and 9 months after the implant. RESULTS: Parkinsonian features improved in all patients--the greatest change seen in rigidity, then tremor, followed by bradykinesia. Compared with the presurgical condition, off-drug UPDRS motor scores improved by 41.9% on the last visit (p = 0.0002), UPDRS activities of daily living (ADL) scores improved by 52.2% (p = 0.0002), and the Schwab & England scale score improved by 213% (p = 0.0002). The levodopa-equivalent daily dose was reduced by 65%. Night sleep improved in all patients due to increased mobility at night, and in five patients insomnia was resolved. All patients gained weight after surgery and their appetite increased. The mean weight gain at the last follow-up was 13% compared with before surgery. During the last visit, the stimulation amplitude was 2.9+/-0.5 V and the total energy delivered per patient averaged 2.7+/-1.4 W x10(-6). The results of patient self-assessment scales indicated a marked improvement in five patients and a moderate improvement in the other two. The neuropsychological data showed no changes. Side effects were mild and tolerable. In all cases, a tradeoff between the optimal voltage and the severity of side effects made it possible to control parkinsonian signs effectively. The most marked side effects directly related to STN stimulation consisted of ballistic or choreic dyskinesias of the neck and the limbs elicited by contralateral STN stimulation above a given threshold voltage, which varied depending on the individual. CONCLUSIONS: Parkinsonian signs can be controlled by bilateral high-frequency STN stimulation. The procedure is well tolerated. On-state dyskinesias were greatly reduced, probably due to the reduction of total antiparkinsonian medication. Bilateral high-frequency STN stimulation compensated for drug reduction and elicited dyskinesias, which differ from those observed following dopaminergic medication. ADL improved significantly, suggesting that some motor tasks performed during everyday chores, and that are not taken into account in the UPDRS motor score, also improved.

Diagnosis of AIDS-related focal brain lesions: a decision-making analysis based on clinical and neuroradiologic characteristics combined with polymerase chain reaction assays in CSF.

OBJECTIVE: To identify disease patterns in AIDS-related focal brain lesions (FBL) and to design a decision-making strategy for differential diagnosis. DESIGN: Prospective study. Probabilities of CNS disorders were calculated using Bayes' theorem according to clinical variables (mass effect at CT or MRI, Toxoplasma serology, anti-Toxoplasma prophylaxis) and to the results of polymerase chain reaction (PCR) assays. PATIENTS: 136 consecutive HIV-infected patients with a definitive diagnosis of FBL-causing disorder observed from 1991 to 1995 in a single clinical setting. INTERVENTIONS: Patients underwent empiric anti-Toxoplasma therapy. After 3 weeks, patients with progressive/stable disease underwent brain biopsy. In 66 patients Epstein-Barr virus (EBV)-DNA, JC virus (JCV)-DNA, and T gondii-DNA amplification was performed by PCR in CSF. Diagnostic criteria were histopathologic examination of bioptic or autoptic tissue specimens for all disorders and complete/partial resolution of FBL after empiric therapy for toxoplasmic encephalitis (TE). RESULTS: Neuroradiologic characteristics did not discriminate between TE and primary CNS lymphoma (PCNSL). Probability of TE was 0.87 in Toxoplasma-seropositive patients with mass effect who were not receiving anti-Toxoplasma prophylaxis, but only 0.59 if prophylaxis was performed. In seronegative patients with mass effect, the likelihood of PCNSL was 0.74. If EBV-DNA or T gondii-DNA tests were positive, the probability of PCNSL or TE increased to more than 0.96. The absence of T gondii-DNA did not exclude the possibility of a TE diagnosis. Among FBL without mass effect, the probability of progressive multifocal leukoencephalopathy (PML) was 0.81; this increased to 0.99 if JCV-DNA testing was positive. Sensitivity of brain biopsy was 93%, with a perioperative morbidity of 12% and a mortality of 2%. CONCLUSIONS: Due to the low diagnostic capability of clinical variables, PCR amplifications in CSF, especially for EBV-DNA and for JCV-DNA, represent, in most cases, an essential step in the differential diagnosis of AIDS-related FBL. This is particularly true in patients with FBL without mass effect or with mass effect and who are either seronegative or undergoing anti-Toxoplasma prophylaxis. Brain biopsy remains a necessary procedure in EBV-DNA-positive cases and in seronegative patients with FBL displaying a mass effect. Positive JCV-DNA testing may obviate the need for brain biopsy in patients with FBL without mass effect. An advanced diagnostic strategy based on combined clinical criteria and PCR tests may allow rapid and accurate identification of patients for prompt brain biopsy or specific therapy.

Noninvasive measures of radiolabeled dextran transport in in situ rabbit lung.

UNLABELLED: Dextrans are nontoxic and can be obtained in a wide variety of molecular weights. The purpose of this study was to label 6-kDa and 40-kDa dextrans with gamma- (99mTc) and positron- (18F) emitting radioisotopes and monitor their transport across the pulmonary microvascular barrier. METHODS: External scan measurements for radiolabeled uncharged dextrans, albumin and red blood cells were obtained in eight blood-perfused in situ rabbit lung preparations. After 3 hr of external scanning, the lungs were removed for postmortem and extravascular distribution volume calculations. Extravascular distribution volumes were obtained in six additional rabbits following 4 hr of dextran perfusion to compare the effect of time. The normalized slope index (NSI), a measure of transvascular transport rate, was calculated for each diffusible tracer. RESULTS: The mean NSI for albumin (0.001676 +/- 0.000537 min-1) was significantly lower than NSI for the 40-kDa dextran (0.002303 +/- 0.0005426 min-1) as well as the 6-kDa dextran (0.004312 +/- 0.001134 min-1). The difference between the 6-kDa and the 40-kDa dextrans was also significant. After 4 hr of equilibration, distribution volumes were not significantly different than those obtained at 3 hr. CONCLUSION: Dextrans can be radiolabeled with gamma and positron emitters and small dextrans traverse the lung microvascular barrier more rapidly than albumin. Our results suggest that the use of small dextrans rather than albumin can reduce scan times in clinical applications and minimize motion artifact associated with the noninvasive gamma detection method.

Alterations in pulmonary artery flow patterns and shear stress determined with three-dimensional phase-contrast magnetic resonance imaging in Fontan patients.

OBJECTIVE: This study compares in vivo pulmonary blood flow patterns and shear stresses in patients with either the direct atrium-pulmonary artery connection or the bicaval tunnel connection of the Fontan procedure to those in normal volunteers. Comparisons were made with the use of three-dimensional phase contrast magnetic resonance imaging. METHODS: Three-dimensional velocities, flows, and pulmonary artery cross-sectional areas were measured in both pulmonary arteries of each subject. Axial, circumferential, and radial shear stresses were calculated with the use of velocities and estimates of viscosity. RESULTS: The axial velocities were not significantly different between subject groups. However, the flows and cross-sectional areas were higher in the normal group than in the two patient groups in both pulmonary arteries. The group with the bicaval connection had circular swirling in the cross section of both pulmonary arteries, causing higher shear stresses than in the controls. The disorder caused by the connection of the atrium to the pulmonary artery caused an increase in some shear stresses over the controls, but not higher than those found in the group having a bicaval tunnel. CONCLUSIONS: We found that pulmonary flow was equally reduced compared with normal flow in both patient groups. This reduction in flow can be attributed in part to the reduced size of the pulmonary arteries in both patient groups without change in axial velocity. We also found higher shear stress acting on the wall of the vessels in the patients having a bicaval tunnel, which may alter endothelial function and affect the longevity of the repair.

Comparison of the effects of saline and homologous plasma infusion on lung fluid balance during endotoxemia in the unanesthetized sheep.

The effects of saline infusion (20 ml/kg/30 minutes) and homologous plasma infusion (20 ml/kg/30 minutes) on the lung fluid balance during increased pulmonary capillary permeability secondary to Escherichia coli endotoxin infusion (1 microgram/kg/15 minutes) were studied in unanesthetized sheep. Saline and homologous plasma infusion increased lung lymph flow by 10.6% and 10.8%, respectively. The bloodless wet-to-dry ratio was 5.1 +/- 0.2 in the saline group and 5.2 +/- 0.2 in the homologous plasma group. The saline infusion decreased the plasma oncotic pressure while the plasma infusion increased plasma oncotic pressure. However, the increase in plasma oncotic pressure was negated by concomitant changes in the lymph oncotic pressure and greater increases in pulmonary microvascular pressure during the plasma infusion. Changes in pulmonary microvascular pressure predominated over changes in the oncotic pressure gradient. Both saline and homologous plasma infusion increase fluid filtration into the interstitial space by the same magnitude. Therefore neither has a clear advantage in the treatment of pulmonary edema during increased permeability.

Venous occlusion measurement of pulmonary capillary pressure: effects of embolization.

The effects of pulmonary arterial embolization on calculated pulmonary capillary pressure as determined by the venous occlusion technique are examined using a simple pressure-flow model for the lung. It is predicted that pulmonary, arterial embolization can induce significant underestimation of pulmonary capillary pressure in flowing vessels. This underestimation is related to the percent of vessels embolized and the caliber of pulmonary arteries that are embolized (i.e., the size of the emboli). Experimental verification of these theoretical findings is necessary before the conclusions can be extended to the interpretation of venous occlusion experiments in the lung.

Analysis of noninvasive macromolecular transport measurements in the lung.

Several groups of investigators are measuring transcapillary protein flux in the lung using noninvasive methods. Results from these studies are reported using several different protein transport indexes, including pulmonary transvascular transfer coefficient, relative extravascular protein, pulmonary transcapillary escape rate, protein leak index, lung transferrin index, slope index, and lung-to-heart count ratios. The purpose of this study is to discover the relationships between these indexes by employing a two-compartment theory of protein transcapillary transport in the lung. We found that all the above indexes can be related to a single index, which we call the normalized slope index. This index is the time rate of change of radioactivity originating from protein in lung interstitium divided by radioactivity arising from protein in lung plasma, normalized by this ratio at time 0, and corrected for blood volume changes. In particular the normalized slope index is shown to be the same as pulmonary transcapillary escape rate under normal sampling conditions and is relatively unaffected by changes in interstitial volume. The response of the normalized slope index to changes in microvascular pressure and microvascular permeability is explored by applying a two-pore model of the microvascular barrier. Results indicate that the normalized slope index is relatively insensitive to changes in microvascular pressure but is greatly affected by changes in microvascular permeability (i.e., changes in large-pore size or number). Since all published leak indexes are related, we would encourage all investigators in the field to adopt a single leak index. We recommend that when a two-compartment model is applied to external detection data, the results be expressed as pulmonary transcapillary escape rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Modeling flux of free and protein-bound radioisotopes into the pulmonary interstitium.

Several groups of investigators are using external detection of radiolabeled protein to study the flux of protein from plasma into the pulmonary interstitium. A basic assumption for these studies has been that the unbound (free) tracer concentration is small and insignificant. The purpose of this study is to evaluate how free tracer influences the determination of normalized slope index. A five-compartment model for the lung was used with transport equations for both unbound and bound nuclide flux. Parameters of the unbound and bound transport equations were varied to evaluate the sensitivity of normalized slope index to each parameter. The model was also compared with published protein flux data to investigate the validity of the transport model. Application of the model to external scan data provides a sensitive method for evaluating the flux of bound and unbound tracers into the pulmonary interstitium. We conclude that because the distribution volume for unbound tracer is large with respect to protein distribution volume, even a small amount of unbound tracer (2-5%) can create large errors in the determination of normalized slope index.

Effects of prolonged elevated microvascular pressure on lung fluid balance in sheep.

Experiments were conducted in seven chronically instrumented unanesthetized sheep to estimate the osmotic reflection coefficient (sigma d) for total proteins and the solvent-drag reflection coefficients (sigma f) for six endogenous protein fractions. We measured the lymph-to-plasma ratio of total proteins (CL/CP) and six protein fractions during base-line conditions and after left atrial pressure elevations of 24-26 h per elevation. We also monitored pulmonary arterial pressure, left atrial pressure, systemic arterial pressure, and lung lymph flow at the various levels of pulmonary microvascular pressure. Our results indicate the CL/CP may require up to 24 h to reach a true steady state. It was found that sigma d is at least 0.89 for total proteins and sigma f is at least 0.84, 0.87, 0.86, 0.92, 0.95, and 0.96 for protein fractions with effective molecular radii of 36, 39.5, 44, 66, 105, and 123 A, respectively. In addition, the sigma f values for various protein fractions obtained from this investigation are compared with the predicted values of various mathematical models of the lung microcirculation.

Effects of air embolism on sheep lung fluid volumes.

Changes in lung fluid volumes and hyaluronan clearance were measured in six awake sheep during increased microvascular permeability induced by pulmonary air embolism (AE). After a 1- to 2-h baseline, filtered room air was infused through a proximal port of a Swan-Ganz catheter for 2 h at a rate sufficient to double pulmonary vascular resistance. The air infusion was discontinued, and the sheep were monitored for an additional 2 h (recovery). Lung lymph flow and protein flux increased during air infusion and continued to increase during recovery. During AE, lymph-to-plasma ratio for albumin decreased while lymph-to-plasma ratio for large protein remained the same. This would suggest that both microvascular pressure and microvascular permeability increase during AE. Protein clearance increased similarly for all protein sizes during AE and recovery. After 2 h of recovery, interstitial and extravascular volumes were elevated with no change in cellular volume. The volume of the interstitium available to albumin was more than twice control. The fraction of the interstitium that excludes albumin was calculated to be 0.32 +/- 0.04, with a 51% reduction in absolute excluded volume 2 h after AE. Clearance of hyaluronan by the lymphatics (normalized to baseline) increased 6- to 10-fold during and after AE. It was estimated that < 2% of the total hyaluronan in the lung would be cleared in 24 h under baseline conditions. This amount increased to approximately 11% under AE conditions and approximately 15% under recovery conditions. Changes in lung fluid volumes and protein clearance indicate increased microvascular permeability 2 h after AE.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of inspiratory resistance loading on lung fluid balance in awake sheep.

Because pulmonary edema has been associated clinically with airway obstruction, we sought to determine whether decreased intrathoracic pressure, created by selective inspiratory obstruction, would affect lung fluid balance. We reasoned that if decreased intrathoracic pressure caused an increase in the transvascular hydrostatic pressure gradient, then lung lymph flow would increase and the lymph-to-plasma protein concentration ratio (L/P) would decrease. We performed experiments in six awake sheep with chronic lung lymph cannulas. After a base-line period, we added an inspiratory load (20 cmH2O) and allowed normal expiration at atmospheric pressure. Inspiratory loading was associated with a 12-cmH2O decrease in mean central airway pressure. Mean left atrial pressure fell 11 cmH2O, and mean pulmonary arterial pressure was unchanged; calculated microvascular pressure decreased 8 cmH2O. The changes that occurred in lung lymph were characteristic of those seen after other causes of increased transvascular hydrostatic gradient, such as increased intravascular pressure. Lung lymph flow increased twice base line, and L/P decreased. We conclude that inspiratory loading is associated with an increase in the pulmonary transvascular hydrostatic gradient, possibly by causing a greater fall in interstitial perimicrovascular pressure than in microvascular pressure.

Effects of hypoproteinemia on lung microvascular protein sieving and lung lymph flow.

Experiments were conducted on five chronically instrumented unanesthetized sheep to determine the effects of sustained hypoproteinemia on lung fluid balance. Plasma total protein concentration was decreased from a control value of 6.17 +/- 0.019 to 3.97 +/- 0.17 g/dl (mean +/- SE) by acute plasmapheresis and maintained at this level by chronic thoracic lymph duct drainage. We measured pulmonary arterial pressure, left atrial pressure, aortic pressure, central venous pressure, cardiac output, oncotic pressures of both plasma and lung lymph, lung lymph flow rate, and lung lymph-to-plasma ratio of total proteins and six protein fractions for both control base-line conditions and hypoproteinemia base-line conditions. Moreover, we estimated the average osmotic reflection coefficient for total proteins and the solvent drag reflection coefficients for the six protein fractions during hypoproteinemia. Hypoproteinemia caused significant decreases in lung lymph total protein concentration, lung lymph-to-plasma total protein concentration ratio, and oncotic pressures of plasma and lung lymph. There were no significant alterations in the vascular pressures, lung lymph flow rate, cardiac output, or oncotic pressure gradient. The osmotic reflection coefficient for total proteins was found to be 0.900 +/- 0.004 for hypoproteinemia conditions, which is equal to that found in a previous investigation for sheep with a normal plasma protein concentration. Our results suggest that hypoproteinemia does not alter the lung filtration coefficient nor the reflection coefficients for plasma proteins. Possible explanations for the reported increase in the lung filtration coefficient during hypoproteinemia by other investigators are also made.

Effect of perfusate hematocrit on urea permeability-surface area in isolated dog lung.

Seven dog lower left lung lobes were statically inflated and perfused at a constant rate for each lobe with a perfusate in which the hematocrit was altered over a wide range. The permeability-surface area of urea was calculated from multiple indicator dilution curves using two separate injectates for each hematocrit level. One injectate contained only 125I-albumin as the vascular reference tracer and the other contained both 51Cr-erythrocytes and 125I-albumin as the vascular reference tracers; both contained [14C]urea as the permeating tracer. The results strongly indicate that the phenomenon of "erythrocyte trapping" of urea does not affect the calculation of urea permeability-surface area product provided the appropriate albumin-erythrocyte composite reference tracer is utilized in its calculation.

Evaluation of perilla ketone-induced unilateral lung injury using external gamma scanning.

We used a modified external gamma scanning technique to quantitate right and left lung permeability changes to iodinated sheep albumin before and after perilla ketone (PK)-mediated unilateral lung injury in seven anesthetized sheep. Three portable gamma scintillation probes containing 2-in. NaI crystals detected radioactivities of 51Cr-labeled red blood cells and 125I-labeled albumin over the right and left lungs and blood, respectively. Radioactivities were monitored for 1 h before and 3 h after infusion of 25 mg/kg PK into a single lung. Calculation of normalized slope index (NSI) (Roselli and Riddle, J. Appl. Physiol. 67: 2343-2350, 1989) over the 30-min interval before PK and over the 60- to 90-min interval after PK for each lung revealed a four- to five-fold NSI increase in lungs receiving PK (0.00237 +/- 0.00065 to 0.0109 +/- 0.0016 min-1) and no increase in contralateral control lungs (0.00214 +/- 0.00065 to 0.00201 +/- 0.00032 min-1). Observed changes in NSI were consistent with postmortem evaluations of each lung. Lungs receiving PK had significantly higher wet-to-dry lung weight ratios and extravascular lung water volumes than contralateral control lungs. Measured bloodless wet-to-dry lung weight ratios were 5.68 +/- 0.39 and 3.27 +/- 0.27 (P < 0.05) for PK and control lungs, respectively.

Regional measurements of pulmonary edema by using magnetic resonance imaging.

A three-dimensional magnetic resonance imaging (MRI) method to measure pulmonary edema and lung microvascular barrier permeability was developed and compared with conventional methods in nine mongrel dogs. MRIs were obtained covering the entire lungs. Injury was induced by injection of oleic acid (0.021-0.048 ml/kg) into a jugular catheter. Imaging followed for 0.75-2 h. Extravascular lung water and permeability-related parameters were measured from multiple-indicator dilution curves. Edema was measured as magnetic resonance signal-to-noise ratio (SNR). Postinjury wet-to-dry lung weight ratio was 5.30 +/- 0.38 (n = 9). Extravascular lung water increased from 2.03 +/- 1.11 to 3.00 +/- 1.45 ml/g (n = 9, P < 0.01). Indicator dilution studies yielded parameters characterizing capillary exchange of urea and butanediol: the product of the square root of equivalent diffusivity of escape from the capillary and capillary surface area (D1/2S) and the capillary permeability-surface area product (PS). The ratio of D1/2S for urea to D1/2S for butanediol increased from 0.583 +/- 0.027 to 0.852 +/- 0.154 (n = 9, P < 0.05). Whole lung SNR at baseline, before injury, correlated with D1/2S and PS ratios (both P < 0.02). By using rate of SNR change, the mismatch of transcapillary filtration flow and lymph clearance was estimated to be 0.2-1.8 ml/min. The filtration coefficient was estimated from these values. Results indicate that pulmonary edema formation during oleic acid injury can be imaged regionally and quantified globally, and the results suggest possible regional quantification by using three-dimensional MRI.

Optical measurement of isolated canine lung filtration coefficients after alloxan infusion.

In this study, lung filtration coefficient (Kfc) was measured in eight isolated canine lung preparations by using three methods: standard gravimetric (Std), blood-corrected gravimetric (BC), and optical. The lungs were held in zone III conditions and were subjected to an average venous pressure increase of 8.79 +/- 0.93 (mean +/- SD) cmH2O. The permeability of the lungs was increased with an infusion of alloxan (75 mg/kg). The resulting Kfc values (in milliliters . min-1 . cmH2O-1 . 100 g dry lung weight-1) measured by using Std and BC gravimetric techniques before vs. after alloxan infusion were statistically different: Std, 0.527 +/- 0.290 vs. 1. 966 +/- 0.283; BC, 0.313 +/- 0.290 vs. 1.384 +/- 0.290. However, the optical technique did not show any statistical difference between pre- and postinjury with alloxan, 0.280 +/- 0.305 vs. 0.483 +/- 0. 297, respectively. The alloxan injury, quantified by using multiple-indicator techniques, showed an increase in permeability and a corresponding decrease in reflection coefficient for albumin (sigmaf). Because the optical method measures the product of Kfc and sigmaf, this study shows that albumin should not be used as an intravascular optical filtration marker when permeability is elevated. However, the optical technique, along with another means of measuring Kfc (such as BC), can be used to calculate the sigmaf of a tracer (in this study, sigmaf of 0.894 at baseline and 0.348 after injury). Another important finding of this study was that the ratio of baseline-to-injury Kfc values was not statistically different for Std and BC techniques, indicating that the percent contribution of slow blood-volume increases does not change because of injury.