When does the influence of maturation on anthropometric and physical fitness characteristics increase and subside?

The relationships between maturation and anthropometric and physical performance characteristics are dynamic and often asynchronous; confounding the capability to accurately evaluate performance during adolescence. This study aimed to (i) examine the influence of chronological age (CA) and somatic maturation (YPHV) upon anthropometric and physical performance parameters, and (ii) identify the transition/change time points in these relationships using segmental regression. N = 969 soccer players (8-18 years of age) completed anthropometric and physical test assessments, including a countermovement jump (CMJ), agility T test, 10 and 20 m sprints, and multistage fitness test (MSFT). When modeled against CA and YPHV, results identified time point phases with increased rates of stature (CA-7.5, YPHV-8.6 cm/y at 10.7-15.2 years or -3.2 to +0.8 YPHV) and body mass gain (CA-7.1, YPHV-7.5 kg/y at 11.9-16.1 years or -1.6 to +4.0 YPHV), followed by gain reductions. Increased rates of sprint performance development (31%-43% gains) occurred at 11.8-15.8 CA or -1.8 to +1.2 YPHV, with gains subsiding thereafter. CMJ, T test, and MSFT gains appeared relatively linear with no change in developmental rate apparent. Developmental tempos did again, however, subside at circa (CMJ and T test) to post-PHV (MSFT). Based on our sample and analysis, periods of increased developmental rates (stature, mass, sprint) were apparent alongside progressive gains for other physical measures, before all subsided at particular age and maturation time points. Findings highlight dynamic asynchronous development of players, physical attributes, and the need to account for the influence of maturation on athletic performance until post-PHV.

Treatment of landfill leachate using an aerated, horizontal subsurface-flow constructed wetland

A pilot-scale subsurface-flow constructed wetland was installed at the Jones County Municipal Landfill, near Anamosa, Iowa, in August 1999 to demonstrate the use of constructed wetlands as a viable low-cost treatment option for leachate generated at small landfills. The system was equipped with a patented wetland aeration process to aid in removal of organic matter and ammonia nitrogen. The high iron content of the leachate caused the aeration system to cease 2 years into operation. Upon the installation of a pretreatment chamber for iron removal and a new aeration system, treatment efficiencies dramatically improved. Seasonal performance with and without aeration is reported for 5-day biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD), ammonia nitrogen (NH(4)-N), and nitrate nitrogen (NO(3)-N). Since winter air temperatures in Iowa can be very cold, a layer of mulch insulation was installed on top of the wetland bed to keep the system from freezing. When the insulation layer was properly maintained (either through sufficient litterfall or replenishing the mulch layer), the wetland sustained air temperatures of as low as -26 degrees C without freezing problems.

Optimization of anabaenopeptin extraction from cyanobacteria and the effect of methanol on laboratory manipulation

Anabaenopeptins are commonly occurring bioactive peptides of cyanobacterial origin. Cyanobacteria (blue-green algae) are known to be capable of producing a large number of biologically active peptides, but the widespread occurrence of anabaenopeptins in particular, makes them ideal candidates for investigating the reasons that cyanobacteria produce such a complex spectrum of peptides and the wider implications of their natural function(s). Despite the identification of these peptides in cyanobacterial samples, little is known about the concentrations produced. For this reason, methods for the quantitative extraction of anabaenopeptins from lyophilized cyanobacterial cells were optimized. Higher yields of anabaenopeptins were obtained using aqueous methanol extraction than using water alone. However, repeat extractions using 50, 70 or 90% aqueous methanol did not result in significantly different total yields of the anabaenopeptin variants, ABPN-A and -B. Similarly, little difference was found in the quantification of purified ABPN-A and -B by high performance liquid chromatography with photodiode array detection (HPLC-PDA) when analyzed in methanol solutions of different concentrations. The effects of solvent concentration on the laboratory handling of ABPN-A and -B in glass and plastic containers were also investigated. Significantly lower concentrations of dissolved ABPN-A and -B were found when aqueous solutions came into contact with plastics, but not 50 or 100% methanol.

Role of magnetic resonance imaging in the diagnosis and single-stage surgical resection of invasive lobular carcinoma of the breast

Background

Conventional imaging with mammography and ultrasonography has a low sensitivity for diagnosis and a tendency to underestimate the extent of invasive lobular carcinoma (ILC) of the breast. The aim was to determine whether magnetic resonance imaging (MRI) had any advantages for the characterization of ILC.

Methods

Twenty patients with histologically proven ILC underwent preoperative imaging with MRI. MRI was performed to aid detection of malignancy in six patients with a clinically suspicious presentation but normal or indeterminate imaging on mammography and ultrasonography. In 14 patients MRI was performed to determine tumour extent.

Results

MRI accurately identified malignancy in five of six patients with normal or indeterminate conventional imaging. In seven of 14 patients in whom MRI was performed to determine tumour extent, it provided significant additional information. These included four patients in whom conventional imaging grossly underestimated tumour size, two patients in whom MRI identified an unsuspected contralateral breast tumour and one patient in whom MRI predicted tumour invasion of the pectoral muscle. The correlation between tumour size on histological examination was better with MRI (r = 0·967) than with mammography (r = 0·663) and ultrasonography (r = 0·673).

Conclusion

MRI can provide considerable additional information in the detection and characterization of ILC.

Synthesis and structural characterization of PHP[(C(5)Me(4))(2)], a monodentate chiral phosphine derived from intramolecular C-C coupling of tetramethylcyclopentadienyl groups: an evaluation of steric and electronic properties

The chiral monodentate phosphine PhP[(C(5)Me(4))(2)] is readily obtained by oxidation of the lithium complex Li(2)[PhP(C(5)Me(4))(2)] with I(2), which couples the two cyclopentadienyl groups to form a five-membered heterocyclic ring. The steric and electronic properties of PhP[(C(5)Me(4))(2)] have been evaluated by X-ray diffraction and IR spectroscopic studies on a variety of derivatives, including Ph[(C(5)Me(4))(2)]PE (E = S, Se), Cp*MCl(4)[P[(C(5)Me(4))(2)]Ph] (M = Mo, Ta), Ir[P[(C(5)Me(4))(2)]Ph](2)(CO)Cl, and CpFe(CO)[PhP[(C(5)Me(4))(2)]]Me. For comparison purposes, derivatives of the related phospholane ligand PhP[Me(2)C(4)H(6)] have also been investigated, including Ph[Me(2)C(4)H(6)]PS, Ir[Ph[Me(2)C(4)H(6)]](2)(CO)Cl, Ir[Ph[Me(2)C(4)H(6)]](2)(CO)Me, Ir[PPh[Me(2)C(4)H(6)]](COD)(Cl), and Pd[P[Me(2)C(4)H(6)]Ph][eta(2)-C(6)H(4)C(H)(Me)NMe(2)]Cl. The steric and electronic properties of PhP[(C(5)Me(4))(2)] are determined to be intermediate between those of PPh(2)Me and PPh(3). Thus, the crystallographic cone angles increase in the sequence PPh(2)Me (134.5 degrees) < PhP[(C(5)Me(4))(2)] (140.2 degrees) < PPh(3) (148.2 degrees), while the electron donating abilities decrease in the sequence PPh(2)Me > PhP[(C(5)Me(4))(2)] > PPh(3). Finally, PhP[(C(5)Me(4))(2)] has a smaller cone angle and is less electron donating than the structurally similar phosphine, PhP[Me(2)C(4)H(6)].

Cold climate wetlands: design and performance

Constructed wetlands are gaining widespread use as a simple, low cost means of wastewater treatment. Introduction of constructed wetlands technology into the northern United States has been limited by the ability of conventional wetland systems to operate without freezing during the winter. A design approach using subsurface-flow constructed wetlands covered with an insulating mulch layer has been demonstrated to prevent freezing. However, introduction of a mulch layer will affect oxygen transfer rates, pollutant removal performance, and plant establishment. These factors must be addressed for successful application of constructed wetlands technology in cold climates.

Validation of a physically based catchment model for application in post-closure radiological safety assessments of deep geological repositories for solid radioactive wastes

The physically based river catchment modelling system SHETRAN incorporates components representing water flow, sediment transport and radionuclide transport both in solution and bound to sediments. The system has been applied to simulate hypothetical future catchments in the context of post-closure radiological safety assessments of a potential site for a deep geological disposal facility for intermediate and certain low-level radioactive wastes at Sellafield, west Cumbria. In order to have confidence in the application of SHETRAN for this purpose, various blind validation studies have been undertaken. In earlier studies, the validation was undertaken against uncertainty bounds in model output predictions set by the modelling team on the basis of how well they expected the model to perform. However, validation can also be carried out with bounds set on the basis of how well the model is required to perform in order to constitute a useful assessment tool. Herein, such an assessment-based validation exercise is reported. This exercise related to a field plot experiment conducted at Calder Hollow, west Cumbria, in which the migration of strontium and lanthanum in subsurface Quaternary deposits was studied on a length scale of a few metres. Blind predictions of tracer migration were compared with experimental results using bounds set by a small group of assessment experts independent of the modelling team. Overall, the SHETRAN system performed well, failing only two out of seven of the imposed tests. Furthermore, of the five tests that were not failed, three were positively passed even when a pessimistic view was taken as to how measurement errors should be taken into account. It is concluded that the SHETRAN system, which is still being developed further, is a powerful tool for application in post-closure radiological safety assessments.

Bis(mercaptoimidazolyl)(pyrazolyl)hydroborato complexes of zinc, cadmium, and cobalt: structural evidence for the enhanced tendency of zinc in biological systems to adopt tetrahedral M[S4] coordination

The bis(2-mercapto-1-methylimidazolyl)(pyrazolyl)hydroborato derivatives [pzBmMe]2Zn, [pzBmMe]2Co, and [pzBmMe]2Cd have been isolated and structurally characterized by X-ray diffraction. Despite their common [pzBmMe]2M composition, each of these complexes adopts a different structure. Thus, (i) the zinc complex exhibits a tetrahedral Zn[S4] structure in which only the sulfur donors coordinate to zinc, (ii) the cobalt complex exhibits a trigonal-bipyramidal Co[S3NH] structure in which one of the pyrazolyl groups and one of the B-H groups coordinate to cobalt, and (iii) the cadmium complex exhibits a six-coordinate Cd[S4H2] structure in which both B-H groups interact with the cadmium center. These comparisons emphasize that zinc has a greater preference for tetrahedral M[S4] coordination than does either cobalt or cadmium, an observation that is in accord with the prevalent role of zinc in the structural sites of enzymes.

Structural studies of the [tris(imidazolyl)phosphine]metal nitrate complexes [[PimPrl,But]M(NO3)]+ (M = Co, Cu, Zn, Cd, Hg): comparison of nitrate-binding modes in synthetic analogues of carbonic anhydrase

X-ray diffraction studies on a series of cationic divalent metal nitrate complexes supported by the tris(1-isopropyl-4-tert-butylimidazolyl)phosphine ligand, [[PimPri,But]M(NO3)]+ (M = Co, Cu, Zn, Cd, Hg), demonstrate that the nitrate ligand coordination mode is strongly dependent upon the metal. With the exception of that for the HgII derivative, the nitrate ligand coordination modes correlate with the activities of metal-substituted carbonic anhydrases, such that the only MII-carbonic anhydrases which exhibit significant activity, i.e., the Zn and Co species, are those for which the [[PimPri,But]M(NO3)]+ complexes possess strongly asymmetric nitrate ligands. This trend supports the notion that access to a unidentate, rather than a bidentate, bicarbonate intermediate may be a critical requirement for significant carbonic anhydrase activity. Interestingly, the nitrate coordination modes in the series of group 12 complexes, [[PimPri,But]M(NO3)]+ (M = Zn, Cd, Hg), do not exhibit a monotonic periodic trend: the bidenticity is greater for the cadmium complex than for either the zinc or mercury complexes. Since HgII-carbonic anhydrase is inactive, the correlation between nitrate coordination mode and enzyme activity is anomalous for the mercury complex. Therefore, it is suggested that the inactivity of HgII-carbonic anhydrase may be consequence of the reduced tendency of the mercury center in HgII-carbonic anhydrase to bind water.

A physically based approach to modelling radionuclide transport in the biosphere

Calculations of radiological risk are required to assess the safety of any potential future UK deep underground repository for intermediate-level and certain low-level solid radioactive wastes. In support of such calculations, contaminant movement and dilution in the terrestrial biosphere is investigated using the physically based modelling system SHETRAN. Two case studies are presented involving modelling of contaminants representing long-lived poorly sorbed radionuclides in the near-surface aquifers and surface waters of hypothetical catchments. The contaminants arise from diffuse sources at the base of the modelled aquifers. The catchments are characterised in terms of detailed spatial data for topography, the river network, soils and vegetation. Simulations are run for temperate and boreal climates representing possible future conditions at a repository site. Results are presented in terms of the concentration of contaminants in the aquifer, in soils and in surface waters; these are used to support the simpler models used in risk calculations.

A prospective comparative study of moderate versus high protein intake for critically ill patients with acute renal failure

Critically ill patients with acute renal failure are traditionally treated with low-protein diets to help control uremia. This dietary approach may be deleterious to the patient's nutritional status and unnecessary, especially if continuous renal placement therapies (CRRT) are used. However, the optimal amount of protein supplementation during CRRT is unknown. In patients receiving CRRT, a high protein intake may result in a positive nitrogen balance in the absence of uncontrolled uremia. Accordingly, we studied nitrogen metabolism in two consecutive cohorts of acute renal failure patients receiving equal amounts of calories but variable amounts of nitrogen. One group received protein according to the preferences of the attending clinician, the other a high and fixed amount of protein (2.5 g/kg/day). Patients treated according to attending clinician preferences received significantly less dietary protein (1.2 g/kg/day vs. 2.5 g/kg/day; p < 0.0001) and had a negative mean nitrogen balance of -5.5 g/day. Patients receiving a high and fixed amount of protein had a less negative mean nitrogen balance (-1.92 g/day). Such patients were more likely to experience a positive nitrogen balance during any 24-h period (53.6% vs. 36.7%; p < 0.05). They also required more aggressive hemofiltration to maintain control of uremia (mean ultradiafiltrate volume: 2145 mL/h vs. 1658 mL/h; p < 0.0001) and had a significantly higher but still acceptable mean plasma urea level (26.6 mmol/L vs. 18 mmol/L; p < 0.0001). Survival was not significantly different in the two groups (37.5% vs. 31.3%). We conclude that a high-protein diet can be safely administered to critically ill patients with acute renal failure receiving continuous renal replacement therapy. Such a high protein intake improves nitrogen balance when compared to moderate protein intake. A low protein intake is unnecessary in patients treated with CRRT.

Indirect learning of event sequences: the effects of divided attention and stimulus continuity

In a serial reaction time (SRT) task, the learning curve is sleeper when the stimuli are presented in a repeating sequential manner rather than in random order (Nissen & Bullemer, 1987). This is true even when subjects report being unaware of the presence of the repeating sequence. The present study examines the nature of this learning under conditions designed to reduce attentional resources and to disrupt the continuity of stimuli. In the first three experiments, subjects were trained in the SRT task, with or without the addition of a secondary tone counting task, and with repeating or non-repeating sequences. The results suggest that some sequence learning occurred despite the presence of a secondary task. Experiment 4 examined the extent of sequence learning when the inter-stimulus interval was varied between trials. The overall results suggest that despite reduced attentional allocation and discontinuous stimulus presentation, some sequence learning occurs. This result supports other work suggesting a dissociation between learning when measured explicitly, and when assessed through performance indicators.

Combined orthotopic liver transplantation and caesarean section for the Budd-Chiari syndrome

Fulminant hepatic failure is a rare complication of pregnancy. We describe a case of Budd-Chiari syndrome that resulted in the need for combined liver transplantation and Caesarean section at 32 weeks' gestation. The anaesthetic and perioperative management are discussed.

Treatment of sepsis-associated severe acute renal failure with continuous hemodiafiltration: clinical experience and comparison with conventional dialysis

The syndrome of sepsis-associated severe acute renal failure is a frequent component of sepsis-induced multiorgan failure. Continuous hemofiltration techniques are often used in its dialytic management but little is known about their impact. The aim of this study is to define the biochemical and clinical impact of continuous hemodiafiltration (CHD) in the management of this syndrome and to retrospectively compare it to that of conventional dialysis. A prospective, cohort study and retrospective comparison with historical controls was conducted at an intensive care unit (ICU) of a tertiary institution. Eighty-seven consecutive septic patients with acute renal failure were treated by continuous hemodiafiltration and 40 consecutive similar patients by conventional dialysis. All new cases of severe acute renal failure with sepsis were treated by means of continuous hemodiafiltration. Historical controls were treated by means of conventional dialysis. Illness and sepsis severity were assessed on admission and prior to initiation of treatment. Biochemical variables were assessed daily. Outcome was measured as discharge from the ICU, duration of oliguria and discharge from hospital. Of the 87 patients treated by hemodiafiltration, 86 had multiorgan failure, 71 (81.6%) septic shock and 52 (59.8%) bacteremia/fungemia. Their APACHE II score on admission was 29.9 and their mean organ failure score prior to treatment was 4.3. Hemodiafiltration resulted in a significant fall in mean urea and creatinine levels within 24 h and in the correction of acidosis. The mean alveolar-arterial gradient fell from 276 to 211 mm Hg (p < 0.02) within 24 h of therapy. Complications were few and mostly related to vascular access.(ABSTRACT TRUNCATED AT 250 WORDS)

Severe acute renal failure: a comparison of acute continuous hemodiafiltration and conventional dialytic therapy

It is unknown whether continuous renal replacement techniques result in diminished morbidity and mortality when compared to conventional dialytic techniques. To investigate this issue a previously described, retrospectively studied group of critically ill patients with severe acute renal failure treated by conventional dialysis (CD) was compared to a prospectively studied group of similar patients treated by acute continuous hemodiafiltration (ACHD). A combined retrospective and prospective clinical and laboratory investigation was carried out for 234 consecutive critically ill patients with severe acute renal failure in the intensive care unit of a tertiary institution. Biochemical, clinical and outcome data in all patients treated by conventional dialytic techniques (intermittent hemodialysis and/or peritoneal dialysis) during a 5-year period were retrospectively analyzed, and a prospective analysis of the same biochemical, clinical and outcome data in all patients treated by acute continuous hemodiafiltration was done over a similar time span, with statistical comparison of findings. One hundred and fifty patients were treated by ACHD and 84 by CD. ACHD patients were more severely ill (mean APACHE II score: 28.2 vs. 25.8; p < 0.01) and older (mean age: 59.9 vs. 55.5 years; p < 0.01). There were no significant differences in the incidence of sepsis, bacteremia and need for mechanical ventilation. ACHD resulted in better control of uremia (mean steady-state plasma urea level: 20.1 vs. 31.7 mmol/l; p < 0.001) and hyperphosphatemia (mean serum phosphate: 1.26 vs. 1.95 mmol/l) after 24 h of initiation of therapy. It also allowed the administration of full nutritional support in a significantly greater percentage of patients (91.3 vs. 64.8%; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Use of a mean systemic filling pressure analogue during the closed-loop control of fluid replacement in continuous hemodiafiltration

PURPOSE

To assess the use and validity of a mean systemic filling pressure analogue (Pmsa) in the closed-loop control of fluid replacement in continuous hemodiafiltration.

METHODS

Cardiovascular variables were computer acquired from bedside monitor. Pmsa was calculated and compared with a target value. Gravitational fluid replacement to the extracorporeal hemodiafiltration circuit was regulated with a computer-controlled clamp.

RESULTS

Ten patients (mean acute physiology and chronic health evaluation II score, 29.7; range, 21-33) received continuous venovenous hemodiafiltration for acute renal failure. Fluid replacement therapy was closed loop controlled to a target Pmsa for a total of 601 hours. During this period, 417 L of ultradiafiltrate were lost, and 409 L of replacement and nutritional fluids were administered. Despite such large fluid shifts, measured hemodynamic variables were kept within a narrow range (hour to hour variability: right atrial pressure, 1 +/- 0.1 mm Hg; mean arterial pressure 5.9 +/- 0.5 mm Hg; cardiac index, 0.44 +/- 0.05 L/m2/min). No complications of the technique occurred.

CONCLUSIONS

The stability of cardiovascular variables achieved during Pmsa-based fluid replacement of critically ill patients with major fluid losses supports the validity of the use of the Pmsa as a measure of intravascular volume status. Such an analogue may be useful in nondialytic environments. The use of Pmsa as the basis for automated fluid replacement was safe.

Asthma requiring mechanical ventilation. A low morbidity approach

STUDY OBJECTIVE

There is considerable uncertainty about the clinical features, respiratory physiology, and optimal management of patients with asthma requiring mechanical ventilation. Furthermore, the ventilatory and pharmacologic management of asthma requiring mechanical ventilation remain controversial. We hypothesized (1) that there are clinically identifiable and pathophysiologically different subgroups presenting with asthma requiring ventilation; (2) that lower dose steroid therapy (< 400 mg/d intravenous hydrocortisone) is adequate; (3) that permissive hypercapnia is safe; (4) that prolonged paralysis is generally unnecessary; and (5) that clinical outcome would be favorable in patients treated with this approach.

DESIGN

Review of medical records and intensive care charts and statistical analysis of findings.

SETTING

ICU of tertiary institution.

PATIENTS

Thirty-five consecutive cases of life-threatening asthma requiring mechanic ventilation.

RESULTS

Three clinical subgroups of ventilation-requiring asthmatics could be identified. Those presenting with steady deterioration (10), those with unstable asthma followed by a sudden "dip" (16), and those with a sudden unexpected dip (9). Patients in the first group had a significantly lower PaCO2 (p < 0.01) at presentation, but required ventilation for longer periods. Those in the second group had a significantly higher PaCO2 (p < 0.01) and required ventilation for a shorter period. Those in the third group had an intermediate PaCO2 level before intubation and the shortest period (p < 0.01) of mechanical ventilation. Five patients experienced their sudden dip after ingesting aspirin. Ten cases received "high" dose hydrocortisone therapy (mean: 980 mg/24 h), and 25 received lower dose hydrocortisone (mean: 341 mg/24 h). No differences in illness severity at presentation or outcome could be detected between these two groups. Mean duration of ventilatory support was 36 h and mean duration of the ICU stay 52.1 h. Muscle relaxation was used in 12 patients for a mean period of 11.1 h. One patient was brain dead on arrival. All others survived.

CONCLUSIONS

Life threatening asthma is an endpoint for several different clinical patterns of disease. No major clinical advantage could be found in our group of patients when high-dose steroids were used. Long-term use of muscle relaxants and prolonged mechanic ventilation are rarely needed in the management of patients with life-threatening asthma and excellent results can be achieved with a relatively simple management strategy.

Acute renal failure in the critically ill: management by continuous veno-venous hemodiafiltration

The consequences of newer techniques of continuous renal replacement therapy in critically ill patients are not yet fully known. The clinical and biochemical impact of continuous veno-venous hemodiafiltration (CVVHD) was, therefore, prospectively studied in 60 critically ill patients with acute renal failure. Prospective clinical, biochemical, and hematological data were collected from patients receiving CVVHD. Over the initial 24 hours of therapy, CVVHD resulted in a decrease in mean plasma urea from 34.5 mmol/L (95% confidence interval [CI], 29.4 to 39.6) to 25 mmol/L (95% CI, 21.8 to 28.2). With continued CVVHD, the mean plasma urea reached a plateau level of 17.6 mmol/L (95% CI, 15.8 to 19.4) at 72 hours. This degree of azotemia control was achieved with ease and essentially without complications during 8,360 hours of therapy despite the presence of multi-organ failure and the aggressive administration of protein nitrogen (0.25 to 0.35 g/kg/day). No abnormalities of serum electrolytes developed during treatment. Survival to intensive care discharge was 46.6% and to hospital discharge 41.6%, despite a mean Acute Physiology and Chronic Health Evaluation (APACHE) II score at presentation of 27.7. Continuous veno-venous hemodiafiltration offers superior azotemia control and a safe approach to renal replacement therapy in critically ill patients. Its use is associated with a comparatively favorable outcome. CVVHD may be regarded as the treatment of choice in such patients.

A prospective comparative study of continuous arteriovenous hemodiafiltration and continuous venovenous hemodiafiltration in critically ill patients

We have prospectively studied and compared two consecutive groups of critically ill patients treated with either continuous arteriovenous hemodiafiltration (CAVHD) (n = 28) or continuous venovenous hemodiafiltration (CVVHD) (n = 25) to establish the technique of choice. The two groups were comparable in mean age (59 v 58 years), mean Acute Physiology and Chronic Health Evaluation (APACHE) II score (29.6 v 27.4, P = NS), requirements for inotropic drugs, and mean number of failing organs (2.9 v 3.2). CVVHD led to a greater amount of hourly ultrafiltrate (mean, 590 v 424 mL; P < 0.001), but urea and creatinine clearances were not significantly different with the two techniques. Twelve patients survived in the CAVHD group (42.8%) and 13 in the CVVHD group (52%; P = NS). The major advantage for CVVHD use was the substantial decrease in the number of access-related complications (2 v 10; P < 0.025). We conclude that while CVVHD does not offer a significant increase in solute clearance, it significantly minimizes vascular access-related morbidity and should therefore be regarded as the therapeutic modality of choice.

A comparison of conventional dialytic therapy and acute continuous hemodiafiltration in the management of acute renal failure in the critically ill

OBJECTIVE

To compare and contrast the clinical outcomes in critically ill patients with acute renal failure managed with either acute continuous hemodiafiltration or conventional dialytic therapies.

DESIGN

Retrospective review of the medical records of 167 consecutive cases of acute renal failure treated at a single center (July 1982-July 1991). Scoring for illness severity (APACHE II, number of failing organs) and assessment of outcome in terms of biochemical control of azotemia, ARF therapy-related morbidity, and overall morbidity and mortality.

SETTING

Tertiary institution.

PATIENTS

167 consecutive critically ill patients with multiorgan failure and acute renal failure.

MEASUREMENTS AND MAIN RESULTS

84 patients received conventional dialytic therapy (CDT) (1982-1988) and 83 acute continuous hemodiafiltration (ACHD) (1988-1991). The etiology of ARF and illness severity indices were similar in both groups (organ failure scores: CDT 3.9 vs. ACHD 4.1; NS). All patients were critically ill, with more severely ill patients within the ACHD groups (mean APACHE II score: CDT 25.8 vs. ACHD 28.1; p < .01). There were no significant differences in pretreatment serum creatinine, glucose, bicarbonate and phosphate, white cell and platelet counts, incidence of disseminated intravascular coagulation, prevalence of sepsis, or evidence of pulmonary and/or peripheral edema. Overall survival was 29.8% for the CDT groups and 41% for the ACHD group (NS). When patients were stratified by severity of illness, survival in those with 2 to 4 failing organs was significantly greater in the ACHD group (CDT 31.1% vs. ACHD 53.8%; p < .025). Similarly, overall survival in patients with intermediate APACHE II scores (24 to 29) was significantly better in those treated with ACHD (CDT 12.5% vs. ACHD 46.4%; p < .025). During the course of ARF, in comparison to CDT, ACHD was associated with greater overall reductions in serum creatinine, and in phosphate and plasma urea, and an increased net nutritional intake.

CONCLUSIONS

ACHD provided biochemical and outcome indicator advantages over conventional dialytic therapy. In patients with 2 to 4 failing organs or an intermediate APACHE II score (24 to 29) a significant survival advantage was demonstrated for ACHD over CDT. Although this study is a retrospective analysis, with all the inherent limitations of such studies, it suggests that ACHD is the treatment of choice for ARF in the critically ill, with maximum benefits seen in those with 2 to 4 failing organs and/or intermediate APACHE II scores.

Fibreoptic bronchoscopy in the critically ill: a prospective study of its diagnostic and therapeutic value

AIM

A prospective study was undertaken to assess the diagnostic value and therapeutic usefulness of fibreoptic bronchoscopy in the critically ill.

METHOD

Fifty-six bronchoscopies were performed in fifty patients. Biochemical, radiological, microbiological and clinical assessments were made before and after each procedure.

RESULTS

Eighteen fibreoptic bronchoscopies were performed for therapeutic indications (32.1%) of which ten (55.6%) yielded a useful outcome. Thirty-eight bronchoscopies were for diagnostic purposes (67.8%) of which 22 (57.9%) were clinically useful. Broncho-alveolar lavage was performed in twenty-eight cases (50%) and it led to a clinically useful diagnosis in 17 (60.7%). There was no major complication. A subgroup of patients was defined (persistent left lower lobe collapse or consolidation following thoracic or abdominal surgery) in whom fibreoptic bronchoscopy usually did not yield a useful outcome.

CONCLUSION

The use of fibreoptic bronchoscopy in the Intensive Care Unit, in combination with the technique of broncho-alveolar lavage, results in a clinically useful outcome in the majority of cases. Fibreoptic bronchoscopy is an effective and safe diagnostic and therapeutic tool in critically ill patients.

Acute renal failure in critical illness. Conventional dialysis versus acute continuous hemodiafiltration

The dialytic therapy of choice in critically ill patients with acute renal failure (ARF) is a matter of controversy. The clinical outcome of such patients managed with either conventional dialytic therapy (CDT) or acute continuous hemodiafiltration (ACHD) was compared through retrospective review of medical records from the intensive care unit of a tertiary institution. Records from 167 critically ill patients with ARF consecutively treated in the same intensive care unit were reviewed. Eighty-four patients with ARF treated by CDT were compared to 83 treated with ACHD. The etiology of ARF and the degree of illness severity were similar in both groups (failing organs: CDT 3.9 vs. ACHD 4.1; mean APACHE II score: CDT 25.8 vs. ACHD 28.1). Overall survival was 29.8% for the CDT patients and 41% for the ACHD group (NS). In those with two to four failing organs, survival was greater in the ACHD group (53.8% vs. 31.1%; p < 0.025). This was also true for patients with an intermediate APACHE II score (24-29) who demonstrated better survival when treated by ACHD (46.4% vs. 12.5%; p < 0.025). Acute continuous hemodiafiltration was associated with better control of azotemia and hyperphosphatemia and increased nutritional intake. This retrospective study suggests that ACHD may offer clinically significant advantages over CDT, particularly in patients with an intermediate degree of critical illness severity.

Management of acute renal failure in the critically ill with continuous venovenous hemodiafiltration

Continuous venovenous hemodiafiltration (CVVHD) has been increasingly utilized for renal replacement therapy in the critically ill. We report details of a prospective study of CVVHD in 12 critically ill patients (7 males, 5 females; mean age 60 years, range 30-72 years; Apache II score mean 27.4, range 21-35) with oligoanuric acute renal failure supported on CVVHD. Vascular access was obtained via double lumen subclavian or femoral cannulae. The mean pretreatment urea was 35.9 mM/L and the mean pretreatment creatinine was 559 microM/L. After 24 h of treatment on CVVHD these fell to a urea mean of 20.3 mM/L and a creatinine mean of 298 microM/L and remained stable at these values for the duration of CVVHD. The mean net ultrafiltrate volume was 551 mL/h, with a urea clearance mean of 26.6 mL/min and a creatinine clearance mean of 23.7 mL/min. There were no complications related to use of the blood pump module or extracorporeal circuit. Excellent hemodynamic stability, control of fluid and electrolyte balance, and azotaemia control were maintained while on CVVHD. Technique survival was 100%. Patient survival was 42%. We conclude that CVVHD is a safe, effective, and durable therapy for the treatment of acute renal failure in the critically ill and that it offers outstanding metabolic control and cardiovascular stability.

Use of continuous haemodiafiltration: an approach to the management of acute renal failure in the critically ill

We have prospectively investigated the effect of a flexible approach to the management of acute renal failure in critically ill patients based on continuous haemodiafiltration (CHD). Fifty critically ill patients (mean APACHE II score 28.1, range 18-37), with a mean age of 59.5 years, were treated with continuous arteriovenous haemodiafiltration (CAVHD) and/or continuous venovenous haemodiafiltration (CVVHD). CHD achieved excellent haemodynamic stability and control of azotaemia in all patients and permitted aggressive parenteral nutrition. The mean blood urea concentration fell from 33.9 mmol/l (95% confidence interval, CI, 29.1-38.7) to a plateau of 17 mmol/l (95% CI 14.3-19.7) after 72 h of therapy despite persistent anuria and the parenteral administration of 0.3 g/kday of protein nitrogen (mean urea clearance: 24.2 ml/min; 95% CI 22.9-25.5). No supplemental dialytic therapy was required during the 9,485 h of treatment. All clinically significant complications related to vascular access (14%). Twenty-two patients (44%) survived to be discharged from the ICU. CHD is relatively safe and effective in the management of acute renal failure in the critically ill.

Continuous arteriovenous haemodiafiltration in the critically ill: influence on major nutrient balances

The impact of continuous arteriovenous haemodiafiltration (CAVHD) on nitrogen, lipid and carbohydrate balance was studied in 9 parenterally fed critically ill patients with acute renal failure. The effects on carbohydrate delivery of varying dialysate glucose concentrations or flow rates were also investigated. The total daily nitrogen loss was a mean of 24.1 g (95% CI 20.9-27.3 g/24 h) with non-urea nitrogen losses of 7.6 g (95% CI 5.6-9.6 g/24 h). Glucose delivery was a mean 5.8 g/h with a dialysate glucose concentration of 1.5% and a flow rate of 1 l/h (95% CI 4.5-7.0 g/h). Carbohydrate delivery increased with increased dialysate glucose concentration (mean 11.4 g/h with 2.5% glucose: 95% CI 9.6-13.1 g/h; mean 14.9 g/h with a 4.25% concentration: 95% CI 10.9-19; and with increased dialysate flow rates (mean 9.6 g/h, 95% CI 6.8-12.4 g/h, using 2 l/h of 1.5% glucose). Only trace amounts of cholesterol and/or triglycerides were detected in occasional ultradiafiltrate samples. CAVHD has an important impact on nitrogen and carbohydrate balance, but not on lipid status. Knowledge of these interactions is crucial for the rational planning of nutritional strategies in the critically ill.

Continuous arteriovenous haemodiafiltration: optimal therapy for acute renal failure in an intensive care setting?

We report the results of continuous arteriovenous haemodiafiltration (CAVHD) treatment in 12 critically ill intensive care patients with acute renal failure (eight males, four females - mean age 60.9 years - range 47 to 76) (APACHE II score 28.8, range 18-37). All patients were oligoanuric or had a rising creatinine (greater than or equal to 100 microM/L per day). Vascular access was obtained by Scribner shunt or wide-bore femoral arterial and venous cannulae. At the beginning of CAVHD therapy the mean plasma urea was 38 mM/L (SE 4.5, 95% confidence interval (CI) 25.1 to 75.6 mM/L) and the mean creatinine was 604 microM/L (SE 70, 95% CI 450-756 microM/L). After 72 hours of therapy, despite oligoanuria, urea concentration had fallen to a mean of 15.7 mM/L (SE 2.4, 95% CI 12.5-22.9 mM/L) and the creatinine concentration to 297 microM/L (SE 25, 95% CI 243-351 microM/L), respectively. The mean ultrafiltrate volume was 441 mL/hr (SE 33, 95%, range 50-1050 mL/hr). There were no complications related to the extracorporeal circuit, the filter, anticoagulant therapy, electrolyte status or changes in patients' haemodynamic state. Excellent biochemical control of azotaemia was uniformly achieved during CAVHD therapy. Five patients (41.6%) survived to be discharged from the Intensive Care Unit. CAVHD is a simple, safe and effective continuous renal replacement therapy. CAVHD offers technical advantages over alternative therapy while providing equivalent or better biochemical control of azotaemia and volume status in critically ill patients with acute renal failure.

Clearance of vancomycin during continuous arteriovenous hemodiafiltration

The clearance of vancomycin during therapy with continuous arteriovenous hemodiafiltration (CAVHD) has been measured in vivo. Vancomycin clearances (n = 16) were 0.636 +/- 0.269 L/h (10.5 +/- 4.46 ml/min). Effective drug clearances were proportional to ultrafiltrate volumes, reflecting convective clearance. Clearances of vancomycin on CAVHD were approximately twice the values seen with continuous arteriovenous hemofiltration. These data allow construction of a dosing schedule for vancomycin therapy in patients receiving renal support via CAVHD.

The value of clinical symptoms in the diagnosis of urinary incontinence in the female

In a study of 566 patients with urinary incontinence the presenting symptom or combination of symptoms were shown to have limited diagnostic predictive value as measured by urodynamic diagnostic criteria.

Electrical injury to the central nervous system

A case of delayed spinal cord damage due to high voltage electric shock is presented. The literature on the subject is reviewed and discussed.

A ten year prospective experience with semi-elective shunt in selected patients for bleeding oesophageal varices

In a prospective study from 1972 to 1982, 38 patients with bleeding oesophageal varices and relatively good liver function were treated by semi-elective or emergent shunt 2-4 weeks after admission. There were no deaths within 3 months of surgery. This constituted 30% of the total 125 patients admitted with bleeding varices during that period. No referred case for treatment of portal hypertension was included in this study. The procedures performed were end-to-side portacaval shunt in 30 cases, lieno renal shunt in seven cases and interposition mesenterico-caval shunt in one case. All patients were admitted to a special unit with a two stage policy of management. Immediate endoscopic diagnosis and balloon tamponade in those with continued bleeding was followed by shunt in selected cases. Follow-up of the 38 patients showed a cumulative survival at 1 year of 89%, at 3 years of 75% and 5 years of 65%. In four cases (13%) a clinical diagnosis of portal systemic encephalopathy was made, all were controlled by medical management. In four of ten follow-up deaths, liver failure was the cause, in none of these cases was encephalopathy a problem. It is concluded that with a policy of early diagnosis and control of haemorrhage, 30% of a typical series of prospectively studied patients admitted with bleeding varices can be treated without mortality by definitive surgery. There was low incidence of encephalopathy and no cases of incapacitating mental confusion. Centralization of treatment and prospective study is essential for the implementation of such a policy of management.