[Show abstract][Hide abstract] ABSTRACT: Purpose of review: Survivors of a critical illness may experience poor physical function and quality of life as a result of reduced skeletal muscle mass and strength during their acute illness. Patients diagnosed with sepsis are particularly at risk, and mechanical ventilation may result in diaphragm dysfunction. Interest in the interaction of these conditions is both growing and important to understand for individualised patient care.
Recent findings: This review describes developments in the presentation of both diaphragm and limb myopathy in critical illness, as measured from muscle biopsy and at the bedside with various imaging and strength testing modalities. The influence of unloading of the diaphragm with mechanical ventilation and peripheral muscles with immobilisation in septic patients has been recently questioned. Systemic inflammation appears to primarily accelerate and accentuate dysfunction, which may be remedied by early mobilisation and augmented with developing muscle and/or nerve stimulation techniques.
Summary: Many acute muscle changes in septic patients are likely to stem from pre-existing impairments, which should provide context for clinical evaluations of strength. During illness, sarcolemmal injury promotes a cascade of intra-cellular abnormalities. As unique characteristics of ICU acquired weakness and differential effects on muscle groups are understood, early diagnosis and management should be facilitated.
Current Opinion in Clinical Nutrition and Metabolic Care 03/2015; 18(3). DOI:10.1097/MCO.0000000000000165 · 3.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Large positive sodium balances, independent of fluid balance, may lead to expanded extracellular fluid volumes and adverse clinical outcomes in the critically ill, including impaired oxygenation.
To estimate sodium and fluid balances in critically ill patients needing invasive mechanical ventilation (MV) for more than 48 hours and to evaluate the relationship between fluid balance, sodium balance and respiratory function (PaO2/FiO2 ratio and length of MV).
A prospective, observational study of 50 patients on MV in four tertiary intensive care units.
Daily sodium and fluid input and output, biochemistry, haemodynamic variables, oxygenation (PaO2/FiO2) and steroid and vasopressor administration were recorded for 3 days after study enrolment. Outcome data included the duration of invasive MV, ICU and hospital mortality and ICU and hospital lengths of stay.
Fifty patients (33 men [66%]) with a mean age of 62.8 years (standard deviation, 14.6 years) and a median admission Acute Physiology and Chronic Health Evaluation III score of 82 (interquartile range [IQR], 61-99) were studied. By Day 3 after enrolment, the median cumulative fluid balance was 2668mL (IQR, 875-3507mL) and the cumulative sodium balance was +717mmol (IQR, +422 to +958mmol). Intravenous steroids and the presence of shock led to a lower daily sodium excretion (P=0.004 and P = 0.01, respectively). A positive sodium balance was associated with a reduction in the next day's PaO2/FiO2 ratio (?=-0.36, P = 0.001) and an increased length of MV (linear regression analysis, P< 0.01). The cumulative fluid balance was not associated with either parameter.
The cumulative positive sodium balance, not the cumulative positive fluid balance, is associated with respiratory dysfunction and an increased length of MV.
Critical care and resuscitation: journal of the Australasian Academy of Critical Care Medicine 03/2015; 17(1):23-8. · 2.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Chronic heart failure (CHF) following coronary artery ligation and myocardial infarction in the rat leads to a homeostatic reduction in surface tension with associated alveolar type II cell hyperplasia and increased surfactant content, which functionally compensates for pulmonary collagen deposition and increased tissue stiffness. To differentiate the effects on lung remodelling of the sudden rise in pulmonary microvascular pressure (Pmv) with myocardial infarction from its consequent chronic elevation, we examined a hypertensive model of CHF.
Cardiopulmonary outcomes due to chronic pulmonary capillary hypertension were assessed at six and 15 weeks following abdominal aortic banding (AAB) in the rat.
At six weeks post-surgery, despite significantly elevated left ventricular end-diastolic pressure, myocardial hypertrophy and increased left ventricular internal circumference in AAB rats compared with sham operated controls (p≤0.003), lung weights and tissue composition remained unchanged, and lung compliance was normal. At 15 weeks post-surgery increased lung oedema was evident in AAB rats (p = 0.002) without decreased lung compliance or evidence of tissue remodelling.
Despite chronically elevated Pmv, comparable to that resulting from past myocardial infarction (LVEDP >19 mmHg), there is no evidence of pulmonary remodelling in the AAB model of CHF.
[Show abstract][Hide abstract] ABSTRACT: Background: Abdominal infections are frequent causes of sepsis and septic shock in the intensive care unit (ICU) and are associated with adverse outcomes. We analyzed the characteristics, treatments and outcome of ICU patients with abdominal infections using data extracted from a one-day point prevalence study, the Extended Prevalence of Infection in the ICU (EPIC) II. Methods: EPIC II included 13,796 adult patients from 1,265 ICUs in 75 countries. Infection was defined using the International Sepsis Forum criteria. Microbiological analyses were performed locally. Participating ICUs provided patient follow-up until hospital discharge or for 60 days. Results: Of the 7,087 infected patients, 1,392 (19.6%) had an abdominal infection on the study day (60% male, mean age 62 +/- 16 years, SAPS II score 39 +/- 16, SOFA score 7.6 +/- 4.6). Microbiological cultures were positive in 931 (67%) patients, most commonly Gram-negative bacteria (48.0%). Antibiotics were administered to 1366 (98.1%) patients. Patients who had been in the ICU for <= 2 days prior to the study day had more Escherichia coli, methicillin-sensitive Staphylococcus aureus and anaerobic isolates, and fewer enterococci than patients who had been in the ICU longer. ICU and hospital mortality rates were 29.4% and 36.3%, respectively. ICU mortality was higher in patients with abdominal infections than in those with other infections (29.4% vs. 24.4%, p < 0.001). In multivariable analysis, hematological malignancy, mechanical ventilation, cirrhosis, need for renal replacement therapy and SAPS II score were independently associated with increased mortality. Conclusions: The characteristics, microbiology and antibiotic treatment of abdominal infections in critically ill patients are diverse. Mortality in patients with isolated abdominal infections was higher than in those who had other infections.
[Show abstract][Hide abstract] ABSTRACT: Background
Indirect assessment of mean pulmonary arterial pressure (MPAP) may assist management of critically ill patients with pulmonary hypertension and right heart dysfunction. MPAP can be estimated as the sum of echocardiographically derived mean right ventricular to right atrial systolic pressure gradient and right atrial pressure; however, this has not been validated in critically ill patients.
This prospective validation study was conducted in patients undergoing pulmonary artery catheterisation during intensive care admission. Pulmonary artery catheter (PAC) measurements of MPAP were contemporaneously compared to MPAP estimated utilising transthoracic echocardiography (TTE)-derived mean right ventricular to right atrial systolic pressure gradient added to invasively measured right atrial pressure.
Of 53 patients assessed, 23 had estimable MPAP using TTE. The mean difference between TTE- and PAC-derived MPAP was 1.9 mmHg (SD 5.0), with upper and lower limits of agreement of 11.6 and −7.9 mmHg, respectively. The median absolute percentage difference between TTE- and PAC-derived MPAP was 7.5%. Inter-rater reliability assessment was performed for 15 patients, giving an intra-class correlation coefficient of 0.96 (95% confidence intervals, 0.89 to 0.99).
This echocardiographic method of estimating MPAP in critically ill patients was not equivalent to invasively measured MPAP, based on our predefined clinically acceptable range (±5 mmHg). The accuracy of this method in critically ill patients was similar to the results obtained in ambulatory patients and compared favourably with regard to the accuracy with echocardiographic estimation of systolic pulmonary arterial pressure. The utility of this technique is limited by frequent inability to obtain an adequate tricuspid regurgitant time-velocity integral in critically ill patients.
[Show abstract][Hide abstract] ABSTRACT: Background:
Because increased serum osmolarity may be lung protective, we hypothesized that increased mortality associated with increased serum sodium would be ameliorated in critically ill patients with an acute respiratory diagnosis.
Data collected within the first 24 hours of intensive care unit (ICU) admission were accessed using ANZICS CORE database. From January 2000 to December 2010, 436,209 patients were assessed. Predefined subgroups including patients with acute respiratory diagnoses were examined. The effect of serum sodium on ICU mortality was assessed with analysis adjusted for illness severity and year of admission. Results are presented as odds ratio (95% confidence interval) referenced against a serum sodium range of 135 to 144.9 mmol/L.
Overall ICU mortality was increased at each extreme of dysnatremia (U-shaped relationship). A similar trend was found in various subgroups, with the exception of patients with respiratory diagnoses where ICU mortality was not influenced by high serum sodium (odds ratio, 1.3 [0.7-1.2]) and was different from other patient groups (P<.01). Any adverse associations with hypernatremia in respiratory patients were confined to those with arterial pressure of oxygen (PaO2)/fraction of inspired oxygen (Fio2) ratios of greater than 200.
High admission serum sodium is associated with increased odds for ICU death, except in respiratory patients.
Journal of Critical Care 06/2014; 29(6). DOI:10.1016/j.jcrc.2014.06.008 · 2.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Global epidemiological data regarding outcomes for patients in intensive care units (ICUs) are scarce, but are important in understanding the worldwide burden of critical illness. We, therefore, did an international audit of ICU patients worldwide and assessed variations between hospitals and countries in terms of ICU mortality.
730 participating centres in 84 countries prospectively collected data on all adult (>16 years) patients admitted to their ICU between May 8 and May 18, 2012, except those admitted for fewer than 24 h for routine postoperative monitoring. Participation was voluntary. Data were collected daily for a maximum of 28 days in the ICU and patients were followed up for outcome data until death or hospital discharge. In-hospital death was analysed using multilevel logistic regression with three levels: patient, hospital, and country.
10 069 patients were included from ICUs in Europe (5445 patients; 54·1%), Asia (1928; 19·2%), the Americas (1723; 17·1%), Oceania (439; 4·4%), the Middle East (393; 3·9%), and Africa (141; 1·4%). Overall, 2973 patients (29·5%) had sepsis on admission or during the ICU stay. ICU mortality rates were 16·2% (95% CI 15·5-16·9) across the whole population and 25·8% (24·2-27·4) in patients with sepsis. Hospital mortality rates were 22·4% (21·6-23·2) in the whole population and 35·3% (33·5-37·1) in patients with sepsis. Using a multilevel analysis, the unconditional model suggested significant between-country variations (var=0·19, p=0·002) and between-hospital variations (var=0·43, p<0·0001) in the individual risk of in-hospital death. There was a stepwise increase in the adjusted risk of in-hospital death according to decrease in global national income.
This large database highlights that sepsis remains a major health problem worldwide, associated with high mortality rates in all countries. Our findings also show a significant association between the risk of death and the global national income and suggest that ICU organisation has an important effect on risk of death.
[Show abstract][Hide abstract] ABSTRACT: Background
Infections are a leading cause of death in patients with advanced cirrhosis, but there are relatively few data on the epidemiology of infection in intensive care unit (ICU) patients with cirrhosis. AimsWe used data from the Extended Prevalence of Infection in Intensive Care (EPIC) II one-day point-prevalence study to better define the characteristics of infection in these patients. Methods
We compared characteristics, including occurrence and types of infections in non-cirrhotic and cirrhotic patients who had not undergone liver transplantation. ResultsThe EPIC II database includes 13,796 adult patients from 1,265 ICUs: 410 of the patients had cirrhosis. The prevalence of infection was higher in cirrhotic than in non-cirrhotic patients (59 vs. 51%, p<0.01). The lungs were the most common site of infection in all patients, but abdominal infections were more common in cirrhotic than in non-cirrhotic patients (30 vs. 19%, p<0.01). Infected cirrhotic patients more often had Gram-positive (56 vs. 47%, p<0.05) isolates than did infected non-cirrhotic patients. Methicillin-resistant Staphylococcus aureus (MRSA) was more frequent in cirrhotic patients. The hospital mortality rate of cirrhotic patients was 42%, compared to 24% in the non-cirrhotic population (p<0.001). Severe sepsis and septic shock were associated with higher in-hospital mortality rates in cirrhotic than in non-cirrhotic patients (41% and 71% vs. 30% and 49%, respectively, p<0.05). Conclusions
Infection is more common in cirrhotic than in non-cirrhotic ICU patients and more commonly due to Gram-positive organisms, including MRSA. Infection in patients with cirrhosis was associated with higher mortality rates than in non-cirrhotic patients.This article is protected by copyright. All rights reserved.
Liver international: official journal of the International Association for the Study of the Liver 03/2014; DOI:10.1111/liv.12520 · 4.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inadvertent sodium (Na(+)) flux may occur during renal replacement therapy (RRT) in ICU. The objective of this study was to estimate sodium flux during RRT.
Between September 2011 to December 2012 we studied 60 ICU patients receiving extended daily dialysis (EDD, Fresenius 4008S) or continuous renal replacement technique (CRRT, Aquarius 6.01). CRRT was categorized as dialysis with continuous veno-venous haemofiltration (CVVH) or haemodiafiltration (CVVHDF). Sodium balance was calculated as the difference between affluent and effluent fluid sodium concentration corrected for volume. The duration of study was either the duration of a single EDD session or 24 h of CRRT.
Both EDD and CRRT contributed to a positive Na(+) flux. Despite similar demographics, CRRT patients had a greater positive sodium flux (p < 0.001). At multivariate analysis, factors [exp(b) (SE), p] which significantly affected sodium flux in each mode of RRT were: (1) EDD (R(2) = 0.42): gradient between RRT Na(+) and serum Na(+) [20.9 (5.8), p < 0.02], and total litres of exchange [1.5 (0.68), p < 0.04]; (2) CVVH (R(2) = 0.77): gradient between RRT Na(+) and serum Na(+) [21.8 (4.7), p < 0.001], dialysis day [-20.9 (9.8), p < 0.05], and total litres of exchange [5.2 (0.96), p < 0.001]; (3) CVVHDF (R(2) = 0.73): gradient between RRT Na(+) and serum Na(+) [23.8 (3.7), p < 0.001], and total fluid removal [-18.5 (3.26), p < 0.001].
RRT may inadvertently contribute to sodium load in critically ill patients and is affected by multiple factors including gradient between RRT Na(+) and serum Na(+).
Journal of nephrology 02/2014; 27(4). DOI:10.1007/s40620-014-0041-8 · 1.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inadvertent sodium administration in excess of recommended daily requirements has been reported during routine care of critically ill patients. Aim: To determine the amount and sources of sodium administered in Australian and New Zealand intensive care units.
Prospective, observational, single-day, point prevalence survey conducted in 46 Australian and New Zealand ICUs on 21 September 2011. All patients present in ICU at 10 am and not receiving an oral diet on the study day were evaluated. Demographic data, ICU admission diagnosis, Acute Physiology and Chronic Health Evaluation (APACHE) II score and sources of sodium administration over the study day were recorded.
356 patients (64% male) were enrolled. Mean (SD) age and weight were 58.5 years (18.0 years) and 81.6 kg (24.0 kg), respectively. Mean ICU admission APACHE II score was 20 (SD, 8). Overall median (interquartile range [IQR]) sodium administration was 224.5 mmol (IQR, 144.9-367.6 mmol), or 2.8 mmol/kg (IQR, 1.6-4.7 mmol/kg). Among patients who were on Day 2-10 of their ICU admission on the study day, sodium sources and amounts administered were: i) maintenance or replacement intravenous (IV) infusions, 69.3mmol; 30.9% of all sodium sources; ii) IV fluid boluses, 36.5 mmol; 16.3%; iii) IV drug boluses, 27.6 mmol; 12.3%; iv) enteral nutrition, 26.5 mmol; 11.8%; v) IV drug infusions, 19.3 mmol; 8.6%; vi) IV flushes, 16.6mmol; 7.4%; vii) blood products, 13.5 mmol; 6%; viii) IV antimicrobials, 11.2mmol; 5%; and ix) parenteral nutrition, 4.3 mmol; 1.9%. Factors associated with sodium administration were site (P = 0.04), age (P < 0.001), administered fluid (P = 0.03) and day of ICU stay (P = 0.01) (multiple linear regression).
This point prevalence study suggests that sodium administration in excess of recommended daily requirements may be common in Australia and New Zealand ICUs. The main sodium source was IV maintenance fluids, followed by fluid boluses and drug boluses.
Critical care and resuscitation: journal of the Australasian Academy of Critical Care Medicine 12/2013; 15(4):294-300. · 2.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Without robust clinical evidence to guide titration of vasopressors in septic shock, it is unclear how dosing of these potent medications occurs. We sought to measure the proportion of vasopressor prescriptions for septic shock that were missing explicit targets and to describe the targets that we identified.
We conducted a multicentre, retrospective cohort study involving 9 intensive care units (ICUs) located at 3 academic hospitals in Canada and Australia. We reviewed charts of consecutive patients aged 18 years or older who were admitted to the ICU for a presumptive diagnosis of sepsis. Other inclusion criteria were hypotension (systolic arterial pressure ≤ 90 mm Hg or mean arterial pressure [MAP] ≤ 65 mm Hg) and continuous infusion of vasopressors for at least 1 hour within the initial 48 hours of ICU stay, the period of observation for this study.
We included data from 369 patient charts. At least 1 target was specified in 99% of charts. The most common targets were MAP measurements (73%). The median initial MAP target was 65 (range 55-90) mm Hg. In multivariable regression models, hospital site and older age of the patient, but not comorbidities of the patient, were associated with MAP targets. In 40% of patients, the treating team modified the initial target at least once.
This study suggests that an explicit blood pressure target accompanies nearly every vasopressor prescription and that patient characteristics have little influence on its value. Identification of a titration strategy that will maximize benefit and minimize harm constitutes a research priority.