Serum albumin: touchstone or totem?

A decrease in serum albumin concentrations is an almost inevitable finding in disease states, and is primarily mediated in the acute phase by alterations in vascular permeability and redistribution. This change is not disease specific but marked changes that persist are generally associated with a poorer prognosis. Critical appraisal of long-standing practices and the availability of alternative colloid solutions have led to a reduction in albumin replacement therapy, and a widespread tolerance of lower albumin concentrations in patients. The factors determining serum albumin concentrations, their measurement and the implications of hypoalbuminaemia are reviewed. The clinical value of serum albumin measurement is discussed.

Fat embolism

Fat embolism syndrome is a collection of respiratory, haematological, neurological and cutaneous symptoms and signs associated with trauma and other disparate surgical and medical conditions. The incidence of the clinical syndrome is low (< 1% in retrospective reviews) whilst the embolisation of marrow fat appears to be an almost inevitable consequence of long bone fractures. There is debate over the pathogenesis of fat embolism syndrome and it seems a variety of factors interact to produce a spectrum of end organ damage. Many therapeutic interventions and prophylactic strategies have been tried with varying success. Current treatments are supportive and the condition is usually associated with a good outcome. The literature on fat embolism syndrome is extensive and this review aims to discuss the incidence, aetiology, pathophysiology, diagnosis and treatment of fat embolism.

Observation of a narrow charmoniumlike state in exclusive B+/--->K+/-pi+pi-J/psi decays

We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.

Combretastatin a-4 analogs as anticancer agents

Combretastatin A-4 (CA-4) is one of the most potent antimitotic and antiangiogenic agents of natural origin. It has displayed potent antitumor effect in a wide variety of preclinical tumor models. Till date various CA-4 analogs have been synthesized and evaluated for anticancer activity. This review is an attempt to compile the medicinal chemistry of various synthesized CA-4 analogs.

Is semiquantitative culture of central vein catheter tips useful in the diagnosis of catheter-associated bacteremia?

Semiquantitative culturing of catheter tips has been used as an index of catheter-related bacteremia. As the sensitivity and predictive values of this test have not been determined, we studied 780 tips from central vein catheters inserted into 440 critically ill patients in an intensive care unit. The results were correlated with clinical data for 30 bacteremic episodes which occurred in these patients, 14 of which were catheter related. When five or more colonies per plate were taken as a positive result, the sensitivity of the method was 92%, and the specificity was 83%. Although the predictive value of a negative result was excellent (99.8%), the predictive value of a positive result was low (8.8%) in our patient population, which had a relatively low incidence of catheter-related bacteremia (2%). We conclude that a semiquantitative culture technique is useful in the diagnosis of bacteremia associated with central vein catheters.

Physiological effects of hyperchloraemia and acidosis

The advent of balanced solutions for i.v. fluid resuscitation and replacement is imminent and will affect any specialty involved in fluid management. Part of the background to their introduction has focused on the non-physiological nature of 'normal' saline solution and the developing science about the potential problems of hyperchloraemic acidosis. This review assesses the physiological significance of hyperchloraemic acidosis and of acidosis in general. It aims to differentiate the effects of the causes of acidosis from the physiological consequences of acidosis. It is intended to provide an assessment of the importance of hyperchloraemic acidosis and thereby the likely benefits of balanced solutions.

Viral hepatitis during pregnancy

OBJECTIVE

A great degree of controversy prevails over the existing reports on the severity and outcome of acute viral hepatitis (AVH) during pregnancy. The present study describes the outcome of AVH associated with pregnancy. A correlation was also assessed for gestation period, viral etiology and outcome of AVH.

METHOD

The serum samples of 273 females with viral hepatitis (age group 18--23 years) were included in the study. Among them, 127 females were pregnant and 146 were non-pregnant cases (as a control group). The sera were screened for seromarkers of the hepatitis A virus (HAV) through to the hepatitis E virus (HEV) by the latest available generation ELISA kits. Among the 127 pregnant females, 83 were AVH cases, while 44 were fulminant hepatic failure (FHF) cases. Among the 146 non-pregnant females, 129 were AVH and 17 were FHF cases.

RESULT

Among the AVH pregnant females, 73 (57.5%) had HEV infection. Fifty-eight percent of the HEV infected pregnant females were associated with FHF. Among non-pregnant females HEV was documented in 67 (46%) cases. HBV infection was observed in 19% and 18% of the pregnant and non-pregnant females, respectively. Twenty percent of the pregnant and 33% of the non-pregnant females remained non-reactive for seromarkers of HAV-HEV. The mortality rate was highest (56%) among HEV infected FHF cases during third trimester of pregnancy. The chi(2) test was applied to check the statistical significance for the differences over the prevalence in various groups.

CONCLUSION

In the present study, HEV was found to be the chief etiological agent, associated with higher morbidity and mortality. However, the incidence of HEV in pregnant females was not significantly different from non-pregnant females. The prevalence of HAV, HCV and HDV were very low in the study. An increased incidence of FHF was noted among HEV infected pregnant females, while infection with an agent other than A-E was commonly associated with FHF among non-pregnant females.

The Chelsea critical care physical assessment tool (CPAx): validation of an innovative new tool to measure physical morbidity in the general adult critical care population; an observational proof-of-concept pilot study

OBJECTIVE

To develop a scoring system to measure physical morbidity in critical care - the Chelsea Critical Care Physical Assessment Tool (CPAx).

METHOD

The development process was iterative involving content validity indices (CVI), a focus group and an observational study of 33 patients to test construct validity against the Medical Research Council score for muscle strength, peak cough flow, Australian Therapy Outcome Measures score, Glasgow Coma Scale score, Bloomsbury sedation score, Sequential Organ Failure Assessment score, Short Form 36 (SF-36) score, days of mechanical ventilation and inter-rater reliability.

PARTICIPANTS

Trauma and general critical care patients from two London teaching hospitals.

RESULTS

Users of the CPAx felt that it possessed content validity, giving a final CVI of 1.00 (P<0.05). Construct validation data showed moderate to strong significant correlations between the CPAx score and all secondary measures, apart from the mental component of the SF-36 which demonstrated weak correlation with the CPAx score (r=0.024, P=0.720). Reliability testing showed internal consistency of α=0.798 and inter-rater reliability of κ=0.988 (95% confidence interval 0.791 to 1.000) between five raters.

CONCLUSION

This pilot work supports proof of concept of the CPAx as a measure of physical morbidity in the critical care population, and is a cogent argument for further investigation of the scoring system.

Performance of six types of oxygen delivery devices at varying respiratory rates

The administration of a known concentration of oxygen is an important part of routine care of the sick patient. Many devices are currently available. The actual concentration of oxygen that can be delivered by these devices can be affected by several factors, both from the patient as well as the device itself. Measuring the F(i)o(2) delivered to the lungs in vivo can be both difficult and potentially uncomfortable for the subjects. We constructed a model using a resuscitation manikin, a ventilator and a set of bellows to simulate ventilation. With this model we tested a series of devices - variable performance, fixed performance and high flow - at two fixed tidal volumes. The respiratory rate was increased and its effect on the oxygen concentration assessed. Variable performance systems such as the Hudson mask deliver a significantly reduced oxygen concentration at high respiratory rates. Fixed performance systems delivering 24-40% oxygen deliver appropriate oxygen concentrations across the range of respiratory rates, whereas those delivering 60% show a reduction in performance. High flow systems show no failure of performance at increased respiratory rates.

Silent myocardial ischaemia and haemoglobin concentration: a randomized controlled trial of transfusion strategy in lower limb arthroplasty

BACKGROUND AND OBJECTIVES

Red cell transfusion is commonly used in orthopaedic surgery. Evidence suggests that a restrictive transfusion strategy may be safe for most patients. However, concern has been raised over the risks of anaemia in those with ischaemic cardiac disease. Perioperative silent myocardial ischaemia (SMI) has a relatively high incidence in the elderly population undergoing elective surgery. This study used Holter monitoring to compare the effect of a restrictive and a liberal red cell transfusion strategy on the incidence of SMI in patients without signs or symptoms of ischaemic heart disease who were undergoing lower limb arthroplasty.

MATERIALS AND METHODS

We performed a multicentre, controlled trial in which 260 patients undergoing elective hip and knee replacement surgery were enrolled and randomized to transfusion triggers that were either restrictive (8 g/dl) or liberal (10 g/dl). Participants were monitored with continuous ambulatory electrocardiogram (ECG) (Holter monitoring), preoperatively for 12 h and postoperatively for 72 h. The tapes were analysed for new ischaemia by technicians blinded to treatment. The total ischaemia time in minutes was divided by the recording time in hours and an ischaemic load in min/h was calculated. Haemoglobin levels were measured preoperatively, postoperatively in the recovery room, and on days one, three and five after surgery.

RESULTS

The mean postoperative haemoglobin concentration was 9.87 g/dl in the restrictive group and 11.09 g/dl in the liberal group. In the restrictive group, 34% were transfused a total of 89 red cell units, and in the liberal group 43% were given a total of 119 red cell units. A postoperative episode of silent ischaemia was experienced by 21/109 (19%) patients in the restrictive group and by 26/109 (24%) patients in the liberal group [mean difference -4.6%; 95% confidence interval (CI): -15.5% to 6%, P = 0.41). There was no significant difference (P = 0.53) between the overall ischaemic load in the restrictive group (median 0 min/h, range 0-4.18) and the liberal group (median 0 min/h, range 0-19.48). In those patients who did experience postoperative SMI, the mean ischaemic load was 0.48 min/h in the restrictive group and 1.51 min/h in the liberal group (ratio 0.32, 95% CI: 0.14-0.76, P = 0.011). The median postoperative length of hospital stay in the restrictive group was 7.3 days [range 5-11; interquartile range (IQR) 6-8] compared with 7.5 days (range 5-13; IQR 7-8) in the liberal group. The numbers were not large enough to conclude equivalence.

CONCLUSIONS

In patients without preoperative evidence of myocardial ischaemia undergoing elective hip and knee replacement surgery, a restrictive transfusion strategy seems unlikely to be associated with an increased incidence of SMI. A proportion of these patients experience moderate SMI, regardless of the transfusion trigger. Use of a restrictive transfusion strategy did not increase length of hospital stay, and use of this strategy would lead to a significant reduction in red cell transfusion in orthopaedic surgery. Our data did not indicate any potential for harm in employing such a strategy in patients with no prior evidence of cardiac ischaemia who were undergoing elective orthopaedic surgery.

Risk factors for pressure sores in the critically ill

Pressure sore development in the critically ill is a well-recognised problem and several risk factors have been put forward as being relevant; however, none has been proved valid in this population. This study examines the effects of specific risk factors for the development of pressure sores in the critically ill. Data on 22 specific risk factors were recorded every 8 h. Of 286 patients who were identified as having a minimum set of three predetermined risk factors, 77 developed pressure sores. Using univariate regression analysis, 18 of the 22 specific factors were identified as being significant (p < 0.05) in the development of pressure sores. Multivariate analysis identified five of these 18 specific risk factors as being independently significant (p < 0.05) in pressure sore development. These five factors were norepinephrine infusion, APACHE II score, faecal incontinence, anaemia and length of stay.

Blood component use in critically ill patients

This prospective observational study was conducted to assess the current transfusion practice in critically ill patients. One thousand two hundred and forty-seven consecutive critically ill patients admitted between February 1999 and October 1999 were included in the study. Overall 666 (53%) patients were administered red cells. Transfused patients had significantly higher intensive care unit mortality but also had higher Acute Physiology and Chronic Health Evaluation II scores and longer durations of stay. The average pretransfusion haemoglobin concentration was < 9 g.dl(-1) in 75% of transfusion episodes. The common indications for transfusion were low haemoglobin (72%) and haemorrhage (25%). Overall, 202 (16%) and 281 (22%) of the patients were transfused platelets and fresh frozen plasma, respectively. The indications for transfusion were haemorrhage, low platelet counts, prolonged prothrombin time or to provide cover for invasive interventions. Most platelet transfusions were given at values in the order of 50-100 x 10(9).l(-1). The pretransfusion platelet count varied according to the indications for transfusion. This study showed that transfusion practice is consistent and that in general there does not seem to be an excessive use of blood components in critically ill patients.

Sepsis associated with central vein catheters in critically ill patients

In 440 critically ill patients, the association between different central vein catheter insertion sites, the duration of catheter insertion and catheter-associated sepsis was examined. Of 780 catheter tips studied, 19% were colonized by microorganisms. The incidence of colonization varied with the different insertion sites. The lowest percentage of colonized catheters occurred with catheters inserted via the subclavian vein (15%) and the highest, at the femoral vein insertion site (34%, p less than 0.01). The percentage of catheters colonized increased as the duration of insertion increased, at all insertion sites studied. Catheter colonization was closely related to the development of bacteraemia and was associated with approximately 10% of colonized catheters. Our results suggest that the subclavian site is associated with the lowest infective complication rate. To minimize catheter associated sepsis, catheters at all insertion sites should be used with parsimony and only kept in place for the minimum amount of time that their continuing use is necessary.

Colloid solutions in the critically ill. A randomised comparison of albumin and polygeline. 1. Outcome and duration of stay in the intensive care unit

All patients admitted to an Intensive Care Unit were randomised to receive all volume replacement fluid as either human albumin solution or a synthetic colloid. A total of 475 patients were admitted during the study period. Patients' age, sex, APACHE score and calculated risk of death were assessed on admission. Outcome was assessed as length of Intensive Care stay and mortality. There was no difference between the groups. Subgroups of patients with APACHE score greater than 10, calculated risk of death greater than 50% and length of stay greater than 5 days were also evaluated but not significant differences were found between treatment groups. The use of albumin rather than 3.5% polygeline for volume replacement in the Intensive Care Unit has no influence on outcome.

Positive pressure ventilation: what is the real cost?

Positive pressure ventilation is a radical departure from the physiology of breathing spontaneously. The immediate physiological consequences of positive pressure ventilation such as haemodynamic changes are recognized, studied, and understood. There are other significant physiological interactions which are less obvious, more insidious, and may only produce complications if ventilation is prolonged. The interaction of positive pressure with airway resistance and alveolar compliance affects distribution of gas flow within the lung. The result is a wide range of ventilation efficacy throughout different areas of the lung, but the pressure differentials between alveolus and interstitium also influence capillary perfusion. The hydrostatic forces across the capillaries associated with the effects of raised venous pressures compound these changes resulting in interstitial fluid sequestration. This is increased by impaired lymphatic drainage which is secondary to raised intrathoracic pressure but also influenced by raised central venous pressure. Ventilation and PEEP promulgate further physiological derangement. In theory, avoiding these physiological disturbances in a rested lung may be better for the lung and other organs. An alternative to positive pressure ventilation might be to investigate oxygen supplementation of a physiologically neutral and rested lung. Abandoning heroic ventilation would be a massive departure from current practice but might be a more rationale approach to future practice.

Low-dose tumour necrosis factor alpha and melphalan in hyperthermic isolated limb perfusion

Nine patients with soft tissue tumours of the lower limb not amenable to treatment other than by isolated limb perfusion or amputation underwent hyperthermic isolated limb perfusion at the level of the superficial femoral vessels, using a combination of recombinant tumour necrosis factor (TNF) alpha and melphalan. In seven patients with superficial tumours, necrosis and sloughing was apparent within 48 h of perfusion. All patients experienced a complete tumour response. There were no systemic side-effects associated with the use of TNF-alpha although local side-effects, particularly oedema, were pronounced. Three patients ultimately required amputation because of the large soft tissue defects that resulted from necrosis of the tumour and overlying skin.

Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1

The reconstruction of the signal from hadrons and jets emerging from the proton-proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals. The resulting topological cell clusters have shape and location information, which is exploited to apply a local energy calibration and corrections depending on the nature of the cluster. Topological cell clustering is established as a well-performing calorimeter signal definition for jet and missing transverse momentum reconstruction in ATLAS.

C-reactive protein as an indicator of resolution of sepsis in the intensive care unit

OBJECTIVE

To investigate the value of decreasing plasma C-reactive protein (CRP) concentrations as an indicator or resolution of microbiologically-proven sepsis.

DESIGN

Retrospective analysis of CRP concentrations measured during episodes of microbiologically-proven sepsis. A receiver-operating characteristic (ROC) curve was used to assess the usefulness of CRP as a test for resolution of sepsis.

SETTING

The intensive care unit (ICU) of a teaching hospital.

PATIENTS AND PARTICIPANTS

32 episodes of microbiologically-proven sepsis occurring in 18 patients were followed from diagnosis until resolution.

MEASUREMENTS AND RESULTS

Daily routine observations and blood testing were performed prospectively. The daily presence or absence of systemic inflammatory response syndrome (SIRS) was prospectively determined according to standard definitions. Concentrations of CRP were analysed retrospectively once the patients had left the ICU. A decrease in CRP by 25% or more from the previous day's level was a good indicator of resolution of sepsis, with a sensitivity of 97%, specificity of 95% and predictive value of 97%. In 13 cases (46%), a decrease in CRP preceded clinical resolution of sepsis; this was more likely to occur in patients with less severe sepsis than in those with severe sepsis or septic shock.

CONCLUSION

Daily measurement of CRP is useful for monitoring the course of microbiologically-proven sepsis in ICU patients, and may be used to indicate successful treatment.