Managing the nonsurgical candidate with an empyema related to community-acquired lobar pneumonia.

This case study reviews the medical management for a 76-year-old patient with a cardiac history and recurrent admissions for a persistent pneumonia. Computed tomography showed evidence of an empyema in the right middle and lower lobes of his lung. The standard treatment for an empyema is a thoracotomy and long-term antibiotics. However, the patient's cardiac history disqualified surgery as an option. Therefore the management plan was composed of antibiotics and treatment of his symptoms. The patient's symptoms improved after a week of levofloxacin (Levaquin), prednisone, bilevel positive airway pressure mask as required, and oxygen. He was discharged with home care, oxygen, Levaquin, tapering doses of prednisone, and previous medications. At a 6-week follow-up examination, the patient was asymptomatic and had marked improvement noted on chest radiograph. The advanced practice nurse played an important role in this patient's recovery by conducting patient education and coordinating follow-up after his release.

Duplex-derived valve closure times fail to correlate with reflux flow volumes in patients with chronic venous insufficiency.

The best way to quantitate venous reflux is still a matter of debate. Duplex-derived valve closure time (VCTs) have been used recently because they can be measured easily. We examined the relationships between VCT and duplex-obtained quantitation of venous volume and between VCT and air plethysmography (APG). Sixty-nine legs in 45 patients with varying clinical degrees of chronic venous insufficiency were studied by duplex scan and APG. VCTs were compared with duplex-derived flow calculations and with APG-derived venous filling index and residual volume fraction. The patient's mean age was 47.5 +/- 13.9 years; the mean duration of their symptoms was 13 +/- 4 years. Twenty percent had a history of deep venous thrombosis, and 29% had undergone venous surgery. No correlation was found between VCT and flow volume or between VCT and flow at peak reflux at any of the anatomic locations studied: saphenofemoral junction, greater saphenous vein, lesser saphenous vein, superficial femoral vein, profunda femoris vein, and popliteal vein. Likewise, no correlation was found between total VCT and APG-derived venous filling index or between total flow volumes and APG-derived residual volume fraction. Total VCT and total flow volumes did, however, have a moderate correlation (r = 0.65; p = 0.0003). Duplex-derived VCTs, although extremely useful in determining the presence of reflux, do not correlate with the magnitude of reflux, and should not be used to quantitate the degree of reflux.

Tissue concentrations of RNA and protein for juvenile brook trout (Salvelinus fontinalis): lagged responses to fluctuations in food availability.

To be useful as short-term indices of nutritional status when food availability varies, wet weight-at-length and tissue concentrations of nucleic acids and protein must covary closely with a fish's recent feeding history. We measured changes in these indices for young brook trout (Salvelinus fontinalis) (fork length: 20-34 mm) reared under alternating, 4 to 5 d periods of food provisioning and food deprivation. Weight-at-length corresponded closely with current feeding conditions, being higher when the trout were fed than when they were deprived. Concentrations of RNA and protein, however, did not correspond closely with current feeding conditions. Instead, there were significant carry-over effects whereby responses to feeding conditions experienced in one treatment period were not exhibited until the following treatment period. Food provisioning had positive carry-over effects on concentrations of RNA and protein while food deprivation had negative carry-over effects. Consequently, food-deprived trout sometimes had higher concentrations of RNA and protein than well fed trout. Since wild fish may experience short-term fluctuations in food availability, lagged responses in concentrations of nucleic acids or protein like those reported here could hamper attempts to use these biochemical measures to assess the nutritional status of juvenile fish in the field.

A prospective study of the determinants of vein graft flow velocity: implications for graft surveillance.

PURPOSE: Serial monitoring of vein graft peak systolic flow velocity (PSFV) has been endorsed as a technique for vein graft surveillance with low values (< 45 cm/sec) considered a marker for impending graft failure. Optimal application of this method requires an understanding of the factors affecting PSFV in normal grafts. A prospective evaluation of 46 consecutive elective infrainguinal vein grafts (6 popliteal/29 tibial/11 pedal) was undertaken to assess the major determinants of PSFV. METHODS: Factors recorded for each patient included vein graft diameter (VGD), measured outflow resistance (MOR), conduit length, outflow level (popliteal/tibial/pedal), inflow level (femoral/popliteal), systolic blood pressure, cardiac ejection fraction, the presence of a patent plantar arch, and Society for Vascular Surgery/International Society for Cardiovascular Surgery resistance scoring. MOR was measured by occluding graft inflow and infusing saline solution through a proximal graft cannula at 60 cc/min while simultaneously recording the pressure at the distal anastomosis via a separate cannula. MOR was calculated by dividing the resultant pressure by the infusion rate. MORs were expressed in resistance units and were measured before and after the infusion of papaverine (MOR(PAP). PSFVs and VGDs were measured 4 to 6 cm from the distal anastomosis 3 weeks after surgery with duplex scanning (60 degree angle with midstream sample volume). RESULTS: PSFVs ranged from 22 to 148 cm/sec and averaged 83.4 +/- 4.8 cm/sec. Pedal bypass grafts had significantly lower PSFVs (64 +/- 10 vs 89.5 +/- 5 cm/sec, p = 0.02) and significantly higher MOR(PAP)s (0.86 +/- 0.15 vs 0.51 +/- 0.05 resistance units, p = 0.05) than bypasses to the popliteal/tibial level. When subjected to univariate analysis the factors correlating with PSFV were MOR (r = -0.59, p = 0.0001), MOR(PAP) (r = -0.69, p = 0.0001) VGD (r = -0.31, p = 0.06), the Society for Vascular Surgery/International Society for Cardiovascular Surgery score (r = -0.35, p = 0.04), inflow level (r = -0.47, p = 0.002), and outflow level (r = -0.35, p = 0.03). When subjected to multiple regression analysis, only MOR(PAP) (r2 = 0.51, p = 0.001) and VGD (r2 = 0.14, p = 0.001) contributed significantly to the overall model (r2 = 0.65, p = 0.0001) with MOR(PAP)) eliminating the effect of the other variables. The multiple regression model predicts PSFV as follows: PSFV = 176 + VGD(mm) (-11.7) + MOR(PAP)) (-63.4). CONCLUSIONS: Clinically successful and hemodynamically normal vein grafts have widely variable, yet predictable flow characteristics that are influenced primarily by outflow resistance and VGD. This wide variability suggests that no single lower threshold value for PSFV is universally applicable indentifying all grafts at risk for failure. Detection of focal areas of flow acceleration within the graft may be more accurate in identifying grafts at risk for failure.

Comparison of descending phlebography with quantitative photoplethysmography, air plethysmography, and duplex quantitative valve closure time in assessing deep venous reflux.

To assess the role of noninvasive tests--quantitative photoplethysmography, air plethysmography, and quantitative duplex scanning, we compared a group of normal (group N, eight limbs) volunteers to patients with severe chronic venous insufficiency who were stratified according to the degree of reflux seen on the current "gold standard," descending phlebography. Group M (10 limbs) had mild (grades 0 to 2) reflux, and group S (10 limbs) had severe (grades 3 to 4) reflux as determined by phlebography. Quantitative photoplethysmography could identify normal from abnormal limbs but could not distinguish the severity of reflux. Air plethysmography was used to calculate venous filling index, ejection fraction, and residual volume fraction. Ejection fraction was the same in all groups. Venous filling index could not significantly distinguish the degree of reflux (group M vs group S) but increased as reflux increased. Residual volume fraction was considerably higher in group S. Quantitative duplex valve closure time was measured in the superficial femoral and popliteal veins, with the values added together in each limb to give a total valve closure time (TVCT). A TVCT value greater than or equal to 4 seconds correlated best with severe phlebographic reflux, with a sensitivity of 90%, a specificity of 94%, and an accuracy of 93%. This value was confirmed as the best test for venous reflux by receiver operating characteristic curve analysis. Thus in the evaluation of patients with severe chronic venous insufficiency who are candidates for phlebography and surgery, quantitative duplex measurement of TVCT gives the best noninvasive assessment of the severity of deep venous reflux.

Femoral vein valvuloplasty: intraoperative angioscopic evaluation and hemodynamic improvement.

Femoral vein valvuloplasty (FVV) is the operation of choice for primary valvular incompetence, but this procedure is highly operator dependent for judging the competence of the valve repair during surgery. We have reviewed our experience with FVV, focusing on the utility of angioscopic-guided valve repair and hemodynamic results. Nine limbs in six patients underwent superficial FVV. There were four men and two women; the average age was 49 years (range 32 to 62 years). All limbs were Society for Vascular Surgery/International Society for Cardiovascular Surgery clinical stage III (venous ulcer), and descending phlebography showed grade 4 reflux in six limbs, grade 3 reflux in one limb, and grade 2 reflux in two limbs. In addition to FVV, five limbs underwent subfascial ligation of incompetent perforators and three limbs underwent ligation and stripping of superficial varicosities. Two limbs underwent polytetrafluoroethylene wrapping of the valvuloplasty. The last five valvuloplasties underwent angioscopic evaluation of the repair, and the last two procedures were closed valvuloplasties (without venotomy). Follow-up averaged 20.3 months (range 2 to 51 months). In all patients ulcers healed without recurrence. There were two perioperative deep vein thromboses in the polytetrafluoroethylene wrapped repairs. All superficial femoral veins were patent by duplex scanning at the time of follow-up. Venous refill time measured by light reflection rheography did not improve after surgery. Venous filling index measured by air plethysmography showed near normalization (3.83 +/- 0.82) after angioscopically guided FVV.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple central place foraging by spider monkeys: travel consequences of using many sleeping sites.

Central place foraging models assume that animals return to a single central place such as a nest, burrow, or sleeping site. Many animals, however choose between one of a limited number of central places. Such animals can be considered Multiple Central Place Foragers (MCPF), and such a strategy could reduce overall travel costs, if the forager selected a sleeping site close to current feeding areas. We examined the selection of sleeping sites (central places) by a community of spider monkeys (Ateles geoffroyi) in Santa Rosa National Park, Costa Rica in relation to the location of their feeding areas. Spider monkeys repeatedly used 11 sleeping trees, and they tended to choose the sleeping site closest to their current feeding area. A comparison of the observed travel distances with distances predicted for a MCPF strategy, a single central place strategy, and a strategy of randomly selecting sleeping sites demonstrated (1) that the MCPF strategy entailed the lowest travel costs, and (2) that the observed travel distance was best predicted by the MCPF strategy. Deviations between the observed distance travelled and the values predicted by the MCPF model increased after a feeding site had been used for several days. This appears to result from animals sampling their home range to locate new feeding sites.