Comparison of lung deposition of colomycin using the HaloLite and the Pari LC Plus nebulisers in patients with cystic fibrosis.

AIM: To examine the effectiveness of delivery of nebulised colistin by the HaloLite nebuliser compared to the Pari LC Plus in patients with cystic fibrosis. METHODS: Randomised crossover trial of 15 patients aged >6 years. Inhalation of one mega unit of colistin in 3 ml diluent, labelled with technetium-99m DTPA, was used to assess lung deposition. The Pari was nebulised to dryness and one button press of the HaloLite was completed. Following a seven day washout period, patients inhaled colistin twice daily for seven days through the first device. Sputum specimens were analysed for colistin levels and pseudomonas load. This procedure was repeated with the alternative device. RESULTS: Lung uptake of radiolabelled colistin was significantly higher with the Pari. However, lung uptake calculated as a percentage of the amount of drug used was significantly higher for the HaloLite. Time to nebulise was significantly shorter with the HaloLite. Sputum levels of colistin were higher following use of the Pari; this was close to significance. CONCLUSION: The manufacturer's recommended dosages for nebulising antibiotics with a HaloLite result in a lower delivery than patients receive when using a Pari nebuliser. The concept of adaptive aerosol delivery has several theoretical advantages but the recommended doses for the HaloLite need to be modified in order to improve effectiveness.

Effects of surgery for postinfarction ventricular tachycardia on parameters of left ventricular function.

Heart failure is the leading cause of death in patients after surgery for ventricular tachycardia. This study examines the effects of antiarrhythmic surgery on 4 parameters of left ventricular (LV) function. Global ejection fraction, segmental wall motion score, homogeneity of contraction, and diastolic function were measured in 32 patients by technetium-99m radionuclide ventriculography. Ejection fraction was measured from the left anterior oblique image. Wall motion score was assessed semiquantitatively for 11 LV segments from 3 projections. Homogeneity of contraction was expressed as the SD of the LV phase analysis curve during systole from the left anterior oblique image. Diastolic function was expressed in terms of peak and mean first time derivative of the action potential (dV/dt) of the LV function curve. Subgroup analyses were performed to distinguish the effects of aneurysmectomy, coronary artery bypass grafting, and changes in angiotensin converting enzyme inhibitor therapy. Mean systolic function improved after surgery (ejection fraction 22% vs 32%, p <0001; wall motion score 20 vs 13, p <0.0001; phase analysis 18 vs 12, p <0.03). Mean diastolic function also improved (peak dV/dt 0.83 +/- 0.32 vs 1.49 +/- 0.39, p = 0.006; mean dV/dt 0.41 +/- 0.15 vs 0.76 +/- 0.27, p = 0.006). Improvements were not confined to those who had aneurysmectomy or coronary bypass grafting and were not explained by changes in vasodilator therapy. Thus, antiarrhythmic surgery does not inherently damage LV function. Significant improvements were observed in most patients. Failure to improve indicated a poor longer term prognosis.

Long-term follow-up of kidney donors: a longitudinal study.

BACKGROUND: Kidney donors are not adversely affected by compensatory hyperfiltration of the remaining kidney in the early years after nephrectomy, but longterm longitudinal studies are lacking. METHODS: The renal function and blood pressure of 75 donors was evaluated in 1984, 1.4-20.7 years after surgery. Forty-seven of the original cohort (23 male, age 38-80 years) underwent repeat study a decade later (12-31 years post-nephrectomy), using identical laboratory techniques. RESULTS: Glomerular filtration rates (GFR) as measured by 51Cr EDTA clearance was relatively unchanged a decade later with 41 of 47 subjects (87%) having EDTA clearance within the normal laboratory reference range at review. The change in GFR in the remaining six subjects was statistically not significant. No correlation between GFR and time after nephrectomy was detected. Albumin excretion rate (AER), on timed overnight urine collections, was increased (> 20 micrograms/min) in 16 subjects (34%), although 14 of these individuals were also hypertensive. The prevalence of hypertension was significantly increased compared with age/sex matched data from epidemiological studies of the general population (both in the UK and the US), especially in those over the age of 55 years. CONCLUSION: This study demonstrates that the function of the solitary kidney is not adversely affected by prolonged compensatory hyperfiltration, although there appears to be an increased prevalence of microalbuminuria and hypertension. Regular follow-up of kidney donors is recommended in order to manage their complications effectively and to detect hypertension and or renal impairment early in those who may develop it.

The use of 99Tcm-DTPA aerosol and caesium iodide mini-scintillation detectors in the assessment of lung injury during cardiopulmonary bypass surgery.

Lung injury is a well-documented adverse effect of cardiopulmonary bypass. The mechanism of injury is not fully understood, but pulmonary hypoxia may be a factor. Post-operative pulmonary epithelial permeability (PEP) in ventilated versus non-ventilated lungs was measured within 2 h of return to the intensive care unit using a 99Tcm-diethylenetriamine pentaacetate aerosol technique. A portable scintillation detector system was required. Sodium iodide detectors have been used previously with this technique but are cumbersome. This study used mini caesium iodide detectors (Oakfield Instruments, Oxon, UK), which can be attached directly to the patient and are more suited to the intensive care setting. The clearance half-time from lung to blood (T1/2LB) was measured in 31 patients (62 lungs). The mean (+/- S.E.M.) clearance half-times were 42.3 +/- 2.7 and 45.7 +/- 3.8 min for non-ventilated and ventilated lungs respectively, with a mean difference of 3.4 +/- 3.1 min (P > 0.05). We conclude that, using this technique, no significant difference in PEP is observed between ventilated and non-ventilated lungs in patients undergoing cardiopulmonary bypass.

Pulmonary endothelial permeability changes after major lung resection.

BACKGROUND: Increased pulmonary endothelial permeability has been proposed as a cause of postpneumonectomy pulmonary edema. This study investigated changes in pulmonary endothelial permeability after major lung resection. METHODS: Lung scintigraphy was performed in 21 men (median age, 66 years; range, 34 to 73 years) after pneumonectomy (10 patients) or lobectomy (11 patients). Pulmonary endothelial permeability was measured by the net pulmonary accumulation of intravenous technetium-99m-labeled albumin, calculated as a ratio of lung:heart radioactivity counts. Pulmonary hemodynamics were monitored continuously by a pulmonary artery catheter, and serum levels of inflammatory cytokines were assayed. RESULTS: The lung:heart radioactivity ratio increased significantly in the initial 8 hours after pneumonectomy but not after lobectomy (p < 0.01). Mean pulmonary artery pressure and pulmonary vascular resistance both increased significantly during pneumonectomy (p < 0.05). The intraoperative increase in mean pulmonary artery pressure was inversely related to preoperative mean pulmonary artery pressure (r = -0.47; p = 0.02). The postoperative change in lung:heart radioactivity ratio to the perioperative increase in pulmonary vascular resistance (r = 0.54; p = 0.02) but not to the increase in mean pulmonary artery pressure (r = 0.14; p > 0.05). Serum interleukin-8 and neutrophil elastase levels were elevated in all patients preoperatively. The postoperative change in lung:heart radioactivity ratio was related to preoperative elastase levels (r = 0.61; p = 0.02). CONCLUSIONS: Pulmonary endothelial permeability appears to be increased after pneumonectomy. Preoperative neutrophil activation and the adaptation of the remaining pulmonary vasculature may be etiologic factors.

Ventilation perfusion radionuclide imaging in cryptogenic fibrosing alveolitis.

There is increasing interest in ventilation perfusion (V/Q) imaging in cryptogenic fibrosing alveolitis because of the data these scans provide on the dynamic V/Q relationships in such patients undergoing single lung transplantation. However, the full spectrum of V/Q abnormalities in this disease is poorly defined. We therefore analysed the V/Q scans of 45 consecutive patients with advanced cryptogenic fibrosing alveolitis being considered for single lung transplantation. Scans were classified according to the presence, severity and degree of matching of defects in ventilation and perfusion images and the results were compared with the data obtained from lung function tests. Ventilation images showed defects in 13 (29%) and 'washout delay' in 15 (33%) patients; 10 (22%) patients had asymmetric distribution of ventilation with one lung receiving > 60% of total ventilation. Perfusion images showed normal perfusion in 8 (18%), mild defects in 18 (40%) and major defects in 19 (42%) patients. The distribution of perfusion between lungs was significantly asymmetric in 20 (45%) patients. V/Q images were matched in 15 (33%), mildly mismatched in 15 (33%) and severely mismatched in 15 (33%) patients, but the degree of V/Q mismatch did not show a relationship to KCO, PaO2 or A-aO2 gradient. The appearances were atypical of pulmonary embolism in eight patients. V/Q images in cryptogenic fibrosing alveolitis show a diverse range of appearances and may mimic pulmonary embolism. V/Q imaging complements the data obtained from lung function tests and is particularly useful in defining the differential function of each lung which is particularly important in the assessment of patients for single lung transplantation.

The long-term stability of reconstituted exametazime: a clinical and laboratory evaluation.

99Tcm-exametazime has become recognized as an effective agent for in vitro leucocyte labelling. However, the material is relatively expensive and exhibits instability, being recommended for use within 30 min. Following subdivision and low-temperature storage of unlabelled exametazime we have evaluated long-term stability in a clinical setting and provided some laboratory support for the observations. Vials of exametazime were reconstituted with sodium chloride injection BP and subdivided into three aliquots prior to storage at -66 degrees C. At intervals up to 27 days they were used for routine leucocyte labelling with percentage labelling efficiency being recorded. Additional aliquots were tested for lipophilic primary complex and radiochemical impurities using thin layer chromatography over a similar period. Results on 92 patients gave a mean leucocyte labelling efficiency of 37% (range 10-78%). Chromatography supported the patient data. The percentage of primary exametazime remaining after 24 days' storage (55%) compared favourably with that in a freshly prepared aliquot, subdispensed but not stored (66%). Subdivision and refrigerated storage of unlabelled exametazime at -66 degrees C appears to preserve its radiolabelling capacity and the ability of the 99Tcm-exametazime to label leucocytes. This combination of long-term stability and improved cost-effectiveness may promote more widespread utilization of this pharmaceutical in clinical nuclear medicine.

The specificity of technetium-labelled-leucocyte imaging of aortic grafts in the early postoperative period.

Radio-labelled-leucocyte imaging is becoming accepted as the investigation of choice when infection of prosthetic arterial bypass grafts is suspected. However, alternative sources of inflammation, such as haematoma and, perhaps, the healing and incorporation of newly inserted bypass grafts, are potential causes of false positive results. This study examines the use of technetium-labelled-leucocyte imaging during the postoperative in-hospital period following aortic bypass surgery. Two labelled-leucocyte scans were carried out serially in 20 patients randomly allocated to receive either of two types of Dacron aortic graft in regular use. The earlier scans were undertaken at 2-5 days after surgery and only two of these scans were positive. None of the later scans, undertaken at 7-10 days after surgery, was positive. None of the patients had a graft injection as evidenced by clinical features, leucocyte counts, and C-reactive protein measurements. These results suggest that recent surgery does not in itself significantly reduce the specificity of technetium-labelled-leucocyte imaging.

New isotopic technique for detecting prosthetic arterial graft infection: 99mTc-hexametazime-labelled leucocyte imaging.

Early and accurate detection of prosthetic arterial graft infection is important because this serious complication of vascular surgery carries high morbidity and mortality rates. This report describes the use of a new method of isotopic imaging to detect graft infection using 99mTc-hexametazime-labelled leucocytes. Seventeen patients with potentially infected arterial grafts were imaged in addition to routine investigations but were managed according to our normal surgical practice. 99mTc-imaging was positive in eight patients with proven graft infection and falsely positive in one patient with a groin haematoma (89 per cent specificity). There were no false negatives (100 per cent sensitivity) after an average follow-up of 6 months (range 3-9 months). This technique has proved a reliable and rapid method of confirming graft infection.

Increase in glomerular filtration rate in patients with insulin-dependent diabetes and elevated erythrocyte sodium-lithium countertransport.

Increased sodium-lithium countertransport in erythrocytes is found in patients with insulin-dependent diabetes mellitus (IDDM) and nephropathy. To determine whether such an increase precedes the onset of nephropathy and, if so, whether it is associated with changes in renal function, we measured erythrocyte sodium-lithium countertransport in 52 patients with IDDM but not nephropathy or hypertension and in 32 control subjects. Seventeen of the 52 patients with IDDM (33 percent) had sodium-lithium countertransport activity that exceeded the maximal activity in the control subjects (0.39 mmol of lithium per hour per liter of cells). Eighteen of the 52 patients with IDDM were studied in more detail. The 7 patients with raised sodium-lithium countertransport values had glomerular filtration rates (median, 159 ml per minute per 1.73 m2 of body-surface area; range, 134 to 197) that were significantly higher (P less than 0.01) than those in the remaining 11 patients with IDDM and normal sodium-lithium countertransport (median, 126 ml per minute per 1.73 m2; range, 110 to 176) or in the 10 control subjects (median, 128 ml per minute per 1.73 m2; range, 93 to 151). In the seven patients with elevated sodium-lithium countertransport, the filtration fraction (median, 0.27; range, 0.22 to 0.37) was also greater (P less than 0.01) than that in control subjects (median, 0.22; range, 0.18 to 0.28). There were no differences in renal function between the patients with IDDM and normal sodium-lithium countertransport and the control subjects. We conclude that sodium-lithium countertransport is increased in patients with IDDM before the onset of nephropathy and is associated with hyperfiltration. Thus, elevated sodium-lithium countertransport activity may be an early marker of diabetic nephropathy.

Effect of a high protein diet in patients with the nephrotic syndrome.

1. Twelve patients with the nephrotic syndrome were prescribed for 4 week periods a normal protein diet (NPD) containing 1 g of protein/kg ideal body weight. They were then prescribed for further 4 week periods in random order diets with high (HPD) and low (LPD) protein contents, respectively 2.0 and 0.5 g/kg ideal body weight. 2. Compliance was confirmed by dietary history and measurement of urinary excretion. 3. Serum albumin was the same on all diets. Twenty-four hour urinary protein excretion increased progressively with increasing dietary protein (LPD 6.1 g. NPD 8.2 g. HPD 9.2 g). Recumbent plasma renin activity and serum phosphate were significantly increased on HPD (plasma renin activity: LPD 5.7, NPD 4.6, HPD 8.2 pmol of angiotensin I min-1 1(-1); serum phosphate: LPD 1.27, NPD 1.26, HPD 1.41 mmol/l). 4. There was no evidence of protein-induced hyperfiltration or hyperperfusion: 51Cr-ethylenediaminetetra-acetate and [125I]iodohippurate clearances were similar on all three diets. 5. Since proteinuria, increased plasma renin levels and hyperphosphataemia may contribute to progression of renal failure and because HPD did not improve hypoalbuminaemia, the use of HPD in the nephrotic syndrome should be abandoned. 6. Until it can be established that LPD, which is accompanied by the least proteinuria, does not, with long-term feeding, lead to malnutrition, NPD should be used in the treatment of the nephrotic syndrome.

Hypertension and renal dysfunction in primary hyperparathyroidism: effect of parathyroidectomy.

1. Twenty-four patients with primary hyperparathyroidism were studied before and 18 restudied 6.5 months (mean) after parathyroidectomy, to investigate the pathogenesis of the hypertension which may accompany this condition. Comparison was made with age-matched patients with essential hypertension and with normotensive control subjects. 2. There was a significant inverse relationship between mean arterial pressure and 51Cr-labelled ethylene-diaminetetra-acetate (51Cr-EDTA) clearance in patients with hyperparathyroidism both before and after parathyroidectomy, but not in patients with essential hypertension. 3. Creatinine clearance appeared to overestimate glomerular filtration rate in some patients with hyperparathyroidism, falling significantly after surgery while 51Cr-EDTA clearance was unchanged. This observation may explain the failure of some previous studies to relate hypertension to impairment of renal function. 4. Plasma renin activity, plasma aldosterone and whole-body exchangeable sodium did not differ between normotensive and hypertensive patients with primary hyperparathyroidism and were unchanged after surgery. 5. Parathyroidectomy did not result in any change in blood pressure or in glomerular filtration rate measured by 51Cr-EDTA clearance.

An evaluation of technetium-99m tin colloid--its value in the diagnosis of renal transplant rejection.

The value of the Technetium-99m tin colloid (TTC) scan in the diagnosis of renal transplant rejection occurring more than 1 month following transplantation was assessed. To our knowledge, use of this agent has not previously been reported. Gamma camera imaging was performed on 15 occasions in 14 patients in whom plasma creatinine was rising and in three patients in whom renal function was stable. Both a qualitative and a quantitative assessment of images was made. The radioactivity recorded over the graft at 12-16 min post injection was expressed as a percentage of that recorded at 0-4 min. In the nine patients in whom graft perfusion was adequate to allow interpretation of the TTC scan and in whom rejection was diagnosed by biopsy (six cases) or on clinical grounds (three cases), the index ranged from 45 to 153%. In two patients the graft was poorly perfused and the accumulation of TTC was predictably low despite the presence of rejection. In the seven patients with either a stable creatinine or with rising creatinine not due to rejection, the index ranged from 5 to 43%. Previously reported studies have shown that sulphur colloids may be of value in diagnosing graft rejection. This study suggests that Tc99m tin colloid may be regarded as a suitable alternative scanning agent and that some simplification of data collection and analysis can be achieved.

Effects of laser treatment on respiratory function in malignant narrowing of the central airways.

Twenty patients with inoperable carcinoma in the trachea or a main bronchus were investigated before and one and 10 days after treatment with a carbon dioxide laser. Patients were assessed by spirometry, maximum flow-volume loops, and a visual analogue score of breathlessness on a scale from 0 (not at all breathless) to 100 (very breathless). At day 10 mean FEV1 had improved from 51.9% to 62.6% of predicted (p less than 0.02) and mean peak expiratory flow (PEF) from 45.3% to 53.1% of the predicted value (p less than 0.05). Improvements in maximum inspiratory and expiratory flows at 50% vital capacity were not significant but the breathlessness score decreased from a mean of 49.1 to 35.3 (p less than 0.01). Improvements in breathlessness were significantly correlated with increases in FEV1 and PEF. Thirteen of the 20 patients had unilateral tumours with partial or complete occlusion of the main bronchus; in these perfusion and ventilation were assessed by radioisotope scans before and 10 days after treatment. Seven of the 13 patients showed an increase in perfusion of the affected lung after treatment but the improvement was small, with a mean increase in unilateral perfusion in the 13 patients of 2.4% of the total counts. Four patients with no perfusion of the affected side showed no significant improvement after laser treatment. Changes in ventilation scans were similar to those in perfusion. It is concluded that laser treatment improves airway function and dyspnoea in malignant narrowing of central airways and that in unilateral obstruction such treatment results, at best, in a small increase in the contribution of the affected lung to perfusion.

Comparison of dynamic computed tomography, diuresis renography and DTPA parenchymal transit time in the assessment of dilatation of the upper urinary tract.

Three methods of assessment of upper urinary tract dilatation were compared prospectively. Forty-eight dilated renal units (35 patients) were studied, the majority being idiopathic pelvic hydronephrosis (69%). Dynamic computed tomography (CT) involves rapid sequence CT after injection of contrast medium. The maximum enhancement of a medullary region of interest (MMR) and its rate of enhancement (SMS) were derived from dynamic CT. Dynamic CT was compared with diuresis probe renography and measurement of parenchymal transit time (PTT) from DTPA imaging. The MMR (70.1 +/- 10.6 HU) and SMS (2.0 +/- 0.5 HU/s) in controls were significantly greater than in patients with upper tract dilatation (52.8 +/- 18.5 and 1.43 +/- 0.85 HU/s; both P less than 0.001). A significant association was observed between impairment of renal function in patients with upper tract dilatation and a low SMS and MMR (P less than 0.01). Statistically significant agreement was observed between the results of diuresis renography and PTT (P less than 0.025). However, no significant agreement was found when the results of dynamic CT were compared with either diuresis renography or with PTT. Dynamic CT as performed in the present study has no useful contribution to make in the diagnosis of patients with dilatation of the upper urinary tract.

Is anaemia during continuous ambulatory peritoneal dialysis really better than during haemodialysis?

The level of anaemia in 22 patients on continuous ambulatory peritoneal dialysis (CAPD) was compared with that in 12 patients maintained on intermittent haemodialysis. Contrary to previous reports, the haematocrit did not differ between these groups, nor did it increase progressively with time in those on CAPD. Total red cell volume (RCV) and plasma volume were also similar in the two groups. Clearance of radioactive iron from plasma (plasma iron turnover) was higher in haemodialysis than in CAPD patients but erythrocyte radioiron utilisation (FeU) did not differ in the two groups. RCV in both CAPD and haemodialysis patients correlated positively with erythrocyte iron turnover and FeU but not with red cell survival, suggesting that the rate of production rather than destruction of red cells is the major determinant of total RCV in dialysis patients. Red cell survival was slightly but significantly higher in CAPD than in haemodialysis patients and increased with time on dialysis, but this difference was insufficient to increase total RCV in CAPD patients above that in haemodialysis patients.