Objective: to compare diafiltered 6% pentastarch (Pentafraction-PDP, MWn 120000 and MWw 280000) and native pentastarch (Pentaspan-PSP, MWn 63000 and MWw 264000 dalton) in a porcine model of faecal peritonitis.Design: Randomised prospective study in 12 adolescent pigs.Interventions: Prior to infection the study solution was infused to increase Qt by 25%. Thereafter adjustments in infusion rate were made (up to 1 l/h) in an attempt to maintain Qt at 25% above baseline values.Measurements and results: Animals were sacrificed at 8h. Tissue was excised from the right lobe of liver and from the right lung and fixed for later electron microscopy and digital morphometric analysis. Patent sinusoidal lumen was significantly greater in group PDP compared to PSP (11.3%±2.3% of liver tissue versus 4.8%±1.1%,p<0.05) and this was accounted for by a significantly lower proportion of sinusoidal lumen occluded with white cells (2.1%±0.6% versus 6.6%±1.9%,p<0.05). Similarly, patent capillary represented a significantly higher proportion of lung tissue for group PDP versus PSP (26.2%±1.9% versus 18.5%±2.7%,p<0.05). The arithmetic mean alveolar capillary barrier thickness was significantly greater in group PSP than in group PDP (4.3±03 μm versus 2.5±03 μm,p<0.01).Conclusions: The molecular weight profile of Pentafraction was associated with less structural organ damage including less tissue oedema and less white cell occlusion.

The effects of two inspiratory flow waveforms (WFs), decelerating and constant have been studied in 14 patients undergoing intermittent positive-pressure ventilation (IPPV). With tidal volume (VT), inspiratory time, inspiratory-expiratory (I/E) ratio and frequency being kept constant, the decelerating waveform produced statistically significant reduction of peak pressure, total respiratory resistance, work of inspiration, ratio of dead space to tidal volume (VD/VT) and alveolar-arterial gradient for oxygen (A-a)PO2. There was significant increase in total static and kinetic compliances and PaO2, with no significant changes in PaCO2, in cardiac output (CO) and in other haemodynamic measurements.

Objective: B-type natriuretic peptide (BNP) has been shown to be a sensitive marker of cardiac dysfunction and to increase in patients with septic shock. This study seeks to confirm these findings in a mixed group of critically ill patients.Design and setting: Prospective observational study in a general intensive care unit (ITU) of a university hospital.Patients and participants: Ninety-three consecutive admissions to the general ITU.Interventions: Measurement of NT-proBNP on admission and then daily thereafter. Collection of clinical and demographical data in relation to NT-proBNP over a period of 5 days and outcome data at 28 days and hospital discharge.Measurements and results: NT-proBNP levels were raised for the whole population at each time point. NT-proBNP levels were higher in non-survivors than in survivors from ITU (p=0.02), at 28 days (p=0.02) or hospital discharge (p=0.0004). NT-proBNP was raised in patients with sepsis (11 688 (6140–20 434) vs. 767 (472–2267) ng/L, p=<0.0001), cardiac dysfunction (7336 (3383–14 906) vs. 757 (428–1819) ng/L, p=<0.0001), requirement for vasoactive therapy (7151 (1089–14 318) vs. 1257 (721–3127) ng/L, p=0.01) and renal support (12 128 (2693–25 831) vs. 1687 (752–3291) ng/L, p=<0.0001). Multiple regression analysis demonstrated that independent predictors of raised NT-proBNP levels were the diagnosis of sepsis (p<0.0001) or ongoing cardiac dysfunction (p=0.006).Conclusions: NT-proBNP levels are raised in critically ill patients. The cause of these increases relates to either sepsis or cardiac dysfunction.

The interpretation and understanding of acid-base dysfunction has recently been revisited. The 'traditional' approach developed from the pioneering work of Henderson and Hasselbalch and is still the most widely used in clinical practice. There are a number of problems identified with this approach, however. The 'modern' approach derives from Stewart's work in physical chemistry. In this review we describe the origins of the traditional approach and discusses related concepts. We then describe Stewart's approach, including how it is derived and how it may be used to classify, acid-base derangements. The applications of Stewart's approach to clinical scenarios in intensive care is then discussed briefly before we examine some published clinical studies based on his work.

OBJECTIVE:To examine whether the strong ion gap (SIG) or standard base excess corrected for abnormalities of serum chloride and albumin (BE(UA)) can predict outcome and to compare the prognostic abilities of these variables with standard base excess (SBE), anion gap (AG), pH, and lactate, the more traditional markers of acid-base disturbance.DESIGN:Prospective, observational study.SETTING:University teaching hospital, general adult ICU.PATIENTS:One hundred consecutive patients on admission to the ICU.MEASUREMENTS AND RESULTS:The anion gap (AG) was calculated and corrected for abnormal serum albumin (AG(corrected)). Serum lactate was measured and SBE, BE(UA), SIG, and APACHE II scores calculated for each patient. 28-day survival was recorded. There was a significant difference between the mean APACHE II (P < 0.001), SBE (P < 0.001), lactate (P = 0.008), AG (P = 0.007), pH (P < 0.001), and BE(UA) (P = 0.009) of survivors and non-survivors. There was no significant difference between the mean SIG (P = 0.088), SIDeff (P = 0.025), and SID app (P = 0.254) between survivors and non-survivors. The pH and SBE demonstrated the best ability of the acid-base variables to predict outcome (AUROC curves 0.72 and 0.71, respectively). Neither of these were as good as the APACHE II score (AUROC 0.76)CONCLUSION:Traditional indices of SBE, BE(UA,) lactate, pH, AG, and APACHE II all discriminated well between survivors and non-survivors. In this group of patients the SIG, SIDeff, and SIGapp appear to offer no advantage in prediction of outcome and their use as prognostic markers can therefore not be advocated.

Predicting the outcome of critical illness remains an evolving art despite many recent advances. This review article describes the tools currently employed, appraising each in turn. The subject is viewed from the perspective that physiological reserve and inflammatory response are the essential elements in assessing prognosis in patients with multi-organ dysfunction/failure, the most commonly encountered syndrome in intensive care practice.

Objective: To examine whether values of arterial base excess or lactate taken on admission to a general intensive care unit indicate prognosis, and whether this can be used as a screening tool for future intensive care admissions. Design: Observational study. Setting: University teaching hospital general adult intensive care unit. Patients: 148 consecutive patients admitted to the intensive care unit. Interventions: Arterial blood samples were obtained on admission to the intensive care unit and 24 h following admission. Measurements and results: Arterial base excess and lactate concentrations were measured from the blood samples. Both base excess and arterial lactate samples on admission have good prognostic abilities (area under the curve on receiver operator characteristic analysis of 0.73, 0.78, respectively). The value of base excess on admission with the best predictive ability was a base excess more negative than –4 mmol/l, and the corresponding value for lactate was greater than 1.5 mmol/l. The combination of these two markers on admission to the intensive care unit led to a sensitivity of 80.3 % and a specificity of 58.7 % for mortality. The achievement of this combination was associated with an increased mortality (50.6 % vs. 15 %, p < 0.0001), older age (70 vs. 61.5 years, p < 0.05), a greater requirement for inotropic support (30.9 % vs. 4.5 %, p < 0.0001) and higher organ failure scores both on admission and for the subsequent 24 h. Conclusions: Both base excess and lactate, or the combination of the two, can be used to predict outcome in patients admitted to the intensive care unit. These variables could be utilized to identify patients who have a high risk for mortality and thus who should be admitted to the intensive care unit.

In the general surgical population, the risk of death within 30 days of an operation is estimated at between 0.7% and 1.7% for most operations and only rises to between 4 and 10% for more risky operations such as cardiac or vascular surgery. However, data from a number of sources suggests that there are a group of surgical patients whose post-operative mortality is between 15 and 35% (Table 1). In England, Wales and Northern Ireland, approximately 2.8 million surgical operations are performed each year and approximately 20000 deaths within 30 days of operation are reported to the National Confidential Enquiry into Post Operative Deaths (NCEPOD). Of these deaths 87% were aged over 60 and 77% were over 70 years of age. Eighty-five percent of these patients had coexisting medical disorders, 45% had significant cardiovascular disease and 30% had significant respiratory disease [1]. The surgeons performing the surgery considered that there was a definite risk of death in nearly 60% of these cases and death was expected in nearly 10% of cases. Respiratory disorders were implicated in nearly 40% of these deaths and cardiac disorders were implicated in over 35% of deaths. Despite this, only 32% of these patients were admitted to an intensive care unit (ICU) or other high care area such as a high dependency unit (HDU). NCEPOD has recognized that those patients who die after surgery are more likely to be elderly, have pre-existing medical disorders and that most deaths occur after abdominal, colorectal or major orthopedic surgery.

The anion gap (AG) and base excess (BE) are used to identify the presence of a metabolic acidosis. A method of analysis using physico-chemical principals has been developed by Stewart and refined by Fencl. This technique has recently been demonstrated to detect unmeasured anions, due to metabolic derangement, more readily than the traditional markers of AG and BE. This method may be a more sensitive indicator of patients with circulatory inadequacy or organ dysfunction. The Fencl-Stewart method of assessing unmeasured anions, resulting in the strong ion gap (SIG), has been shown to be more strongly associated with mortality in paediatric patients than BE or AG [1]. This study examines the predictive value of these measurements in an adult population of critically ill patients.

Copyright © by 2000 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.

Copyright © by 2000 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.

Objectives: Encephalopathy is a common complication of sepsis. This review describes the different pathologic mechanisms that may be involved in its etiology.Data Sources: The studies described here were derived from the database PubMed (http:\\www.nlm.nih.gov) and from references identified in the bibliographies of pertinent articles and books. The citations are largely confined to English language articles between 1966 and 1998. Older publications were used if they were of historical significance.Study Selection: All investigations in which any aspect of septic encephalopathy was reported were included. This selection encompasses clinical, animal, and in vitro cell culture work.Data Extraction: The literature cited was published in peer-reviewed clinical or basic science journals or in books.Data Synthesis: Contradictions between the results of published studies are discussed.Conclusions: The most immediate and serious complication of septic encephalopathy is impaired consciousness, for which the patient may require ventilation. The etiology of septic encephalopathy involves reduced cerebral blood flow and oxygen extraction by the brain, cerebral edema, and disruption of the blood-brain barrier that may arise from the action of inflammatory mediators on the cerebrovascular endothelium, abnormal neurotransmitter composition of the reticular activating system, impaired astrocyte function, and neuronal degeneration. Currently, there is no treatment.

Older patients, especially those with co-morbid disease, who undergo major surgical procedures have significant morbidity and mortality and represent a considerable proportion of the patients requiring intensive care in the UK [1, 2]. As a result of this widely acknowledged fact, a considerable amount of research has been undertaken to reliably identify patients at high risk, and assess a variety of interventions which aim to improve their outcome. Despite this body of work, as with so many areas in intensive care medicine, there remain more questions than answers. What evidence does exist, strongly suggests that intervention in this group of patients can yield dramatic results. However, the timing and nature of this pro-active approach remains a matter of considerable debate.

Crit Care 1999, 3 3 ( (s su up pp pl l 1 1) ):P1 I In nt tr ro od du uc ct ti io on n: : Critically ill patients requiring intensive care are at risk of iatrogenic ocular damage.Studies have reported an incidence of eye problems of up to 40% in critically ill ventilated patients.We conducted this study to assess the incidence of ocular complications in our intensive care unit where all patients are cared for according to an eye care standard.M Me et th ho od ds s: : All ventilated patients over a 2 month period were included.Ophthalmic assessment was performed on admission and repeated every other day during the period of ventilation.At each assessment the average Ramsey sedation score over the previous 24 h, the presence of tracheal secretions and the presence of ventilation associated pneumonia was noted.Eye care performed was recorded.R Re es su ul lt ts s: : Sixty patients were included.One patient developed corneal exposure keratopathy.No patient developed conjunctivitis or corneal ulceration.Further advice on appropriate measures of eye care was given in five cases (8%).Nine patients (15%) had large amounts of respiratory secretions with positive microbiological results.C Co on nc cl lu us si io on n: : This study confirms that the use of an eye care standard is associated with a low incidence of ocular surface complications.The incidence of ocular complications in this group of patients is far lower than previously described.

In an attempt to reduce morbidity and mortality, more invasive and sophisticated monitors are being utilized in the intensive care unit (ICU) and operating rooms. The availability of this new generation of monitors has made possible the treatment of an increasingly sicker group of patients, due to the ability to have real-time and accurate assessments of cardiovascular instability. This improvement in hemodynamic monitoring is vital since basic clinical signs only react very late to problems, due to the body’s remarkable protective mechanisms at preserving essential organ integrity at all costs.