Miscellaneous central nervous system intoxicants

The topic of central nervous system intoxicants encompasses a multitude of agents. This article focuses on three classes of therapeutic drugs, with specific examples in which overdoses require admission to the intensive care unit. Included are some of the newer antidepressants, the atypical neuroleptic agents, and selected anticonvulsant drugs. The importance of understanding pertinent physiology and applicable supportive care is emphasized.

Common laboratory tests predict imminent death in ward patients

OBJECTIVE

To estimate the ability of commonly measured laboratory variables to predict an imminent (within the same or next calendar day) death in ward patients.

DESIGN

Retrospective observational study.

SETTING

Two university affiliated hospitals.

PATIENTS

Cohort of 42,701 patients admitted for more than 24 hours and external validation cohort of 13,137 patients admitted for more than 24 hours.

INTERVENTION

We linked commonly measured laboratory tests with event databases and assessed the ability of each laboratory variable or combination of variables together with patient age to predict imminent death.

MEASUREMENTS AND MAIN RESULTS

In the inception teaching hospital, we studied 418,897 batches of tests in 42,701 patients (males 55%; average age 65.8 ± 17.6 years), for a total of >2.5 million individual measurements. Among these patients, there were 1596 deaths. Multivariable logistic modelling achieved an AUC-ROC of 0.87 (95% CI: 0.85-0.89) for the prediction of imminent death. Using an additional 105,074 batches from a cohort of 13,137 patients from a second teaching hospital, the multivariate model achieved an AUC-ROC of 0.88 (95% CI: 0.85-0.90).

CONCLUSIONS

Commonly performed laboratory tests can help predict imminent death in ward patients. Prospective investigations of the clinical utility of such predictions appear justified.

Efficacy of a rapid response team on reducing the incidence and mortality of unexpected cardiac arrests

Background

Rapid Response Teams (RRTs) assess patients during early phases of deterioration to reduce patient morbidity and mortality.

Objectives

This study aimed to evaluate the ability of earlier medical intervention by a RRT prompted by clinical instability in patients to reduce the incidence of and mortality from unexpected cardiac arrest at our hospital.

Patients and Methods

A nonrandomized, population-based study before 2008 and after 2010 introduction of the Rapid Response Teams in a 300 bed private hospital. All patients were admitted to the hospital in 2008 (n = 25348) and 2010 (n = 28024). RRT (One doctor, one senior intensive care nurse and one staff nurse) attended to clinically unstable patients immediately with resuscitation drugs, fluid, and equipment. Response was activated by the bedside nurse or doctor according to predefined criteria. Main outcome measures were incidence and outcome of unexpected cardiac arrest.

Results

The incidence of unexpected cardiac arrest was 17 per 1000 hospital admissions (431 cases) in 2008 (before RRT intervention) and 12.45 per 1000 admissions (349 cases) in 2010 (after intervention), with mortality being 73.23% (274 patients) and 66.15% (231 patients) respectively. After adjustment for case mix the intervention was associated with a 19% reduction in the incidence of unexpected cardiac arrest (odds ratio 0.81, 95% confidence interval 0.65-0.98).

Conclusions

The RRT was able to detect preventable adverse events and reduce the mortality and incidence of unexpected cardiac arrests.

Differences in outcomes between ICU attending and senior resident physician led medical emergency team responses

INTRODUCTION

Although rapid response systems (RRS) have been shown to decrease the incidence of cardiac arrest (CA), there are no studies evaluating optimal staffing. We hypothesize that there are no outcome differences between ICU physician and senior resident led events.

METHODS

A retrospective study of the RRS database at a single, academic hospital was performed from July 1, 2006 to May 31, 2010. Surgical patients and those in the ICU were excluded. Daytime (D) was defined as 7 am-5 pm Monday through Friday, and weekends were defined as 5 pm on Friday to 6:59 am on Monday. The nurse to patient ratio is constant during all shifts. An ICU physician leads daytime events on weekdays whereas night/weekend (NW) events are led by residents. NW events were compared against D events using chi square or Fischer's exact test. Significance was defined as p<0.05.

RESULTS

A total of 1404 events were reviewed with 534 (38%) D and 870 (62%) NW events. Respiratory and staff concerns were more likely during NW compared to D (50% vs. 39% and 46% vs. 34%, p<0.001, respectively). Following RRS activation, no difference was noted between D and NW periods in the incidence of progression to CA, transfer to ICU, or hospital mortality. Invasive procedures were more common in the NW period.

CONCLUSION

Resident-led RRS may have similar outcomes to attending intensivist led events. Prospective studies are needed to determine the ideal team composition.

Inotropes and vasopressors: more than haemodynamics!

Circulatory shock is characterized by arterial hypotension requiring fluid resuscitation combined with inotropes and/or vasopressors to correct the otherwise life-threatening impairment of oxygen supply to peripheral tissues. Catecholamines represent the current therapeutic choice, but this standard is only based on empirical clinical experience. Although there is evidence that some catecholamines may be better than others, it is a matter of debate which one may be the most effective and/or the safest for the different situations. In their review in this issue of the British Journal of Pharmacology, Bangash et al. provide an overview of the pharmacology as well as the available clinical data on the therapeutic use of endogenous catecholamines, their synthetic derivatives and a range of other agents (vasopressin and its analogues, PDE inhibitors and levosimendan). The authors point out that, despite well-established receptor pharmacology, the clinical effects of these treatments are poorly understood. Hence, further investigations are essential to determine which catecholamine, or, in a broader sense, which alternative vasopressor and/or inotrope is the most appropriate for a particular clinical condition.

Implementation of a protocol facilitates evidence-based physiotherapy practice in intensive care units

OBJECTIVES

To compare the physiotherapy service provided when therapists' decisions are guided by an evidence-based protocol with usual care (i.e. patient management based on therapists' clinical decisions).

DESIGN

Exploratory, controlled, pragmatic sequential time block clinical trial.

SETTING

Level 3 surgical unit in a tertiary hospital in South Africa.

PARTICIPANTS

All patients admitted consecutively to the surgical unit over a 3-month period were allocated to usual or protocol care based on date of admission.

INTERVENTIONS

Usual care was provided by clinicians from the hospital department, and non-specialised physiotherapists were appointed as locum tenens to provide evidence-based protocol care.

MAIN OUTCOME MEASURES

Patient waiting time, frequency of treatment sessions, tasks performed and adverse events.

RESULTS

During protocol-care periods, treatment sessions were provided more frequently (P<0.001) and with a shorter waiting period (P<0.001). It was more likely for a rehabilitation management option to be included in a treatment session during protocol-care periods (odds ratio 2.34, 95% confidence interval 1.66 to 3.43; P<0.001). No difference in the risk of an adverse event was found between protocol-care and usual-care periods (P=0.34).

CONCLUSIONS

Physiotherapy services provided in intensive care units (ICUs) when the decisions of non-specialised therapists are guided by an evidence-based protocol are safe, differ from usual care, and reflect international consensus on current best evidence for physiotherapy in ICUs. Non-specialised therapists can use this protocol to provide evidence-based physiotherapy services to their patients. Future trials are needed to establish whether or not this will improve patient outcome.

Impact of a standardized nurse observation protocol including MEWS after Intensive Care Unit discharge

BACKGROUND

Analysis of in-hospital mortality after serious adverse events (SAE's) in our hospital showed the need for more frequent observation in medical and surgical wards. We hypothesized that the incidence of SAE's could be decreased by introducing a standard nurse observation protocol.

AIM

To investigate the effect of a standard nurse observation protocol implementing the Modified Early Warning Score (MEWS) and a color graphic observation chart.

METHODS

Pre- and post-intervention study by analysis of patients records for a 5-day period after Intensive Care Unit (ICU) discharge to 14 medical and surgical wards before (n=530) and after (n=509) the intervention.

RESULTS

For the total study population the mean Patient Observation Frequency Per Nursing Shift (POFPNS) during the 5-day period after ICU discharge increased from .9993 (95% C.I. .9637-1.0350) in the pre-intervention period to 1.0732 (95% C.I. 1.0362-1.1101) (p=.005) in the post-intervention period. There was an increased risk of a SAE in patients with MEWS 4 or higher in the present nursing shift (HR 8.25; 95% C.I. 2.88-23.62) and the previous nursing shift (HR 12.83;95% C.I. 4.45-36.99). There was an absolute risk reduction for SAE's within 120h after ICU discharge of 2.2% (95% C.I. -0.4-4.67%) from 5.7% to 3.5%.

CONCLUSION

The intervention had a positive impact on the observation frequency. MEWS had a predictive value for SAE's in patients after ICU discharge. The drop in SAE's was substantial but did not reach statistical significance.

Does lactate measurement performed on admission predict clinical outcome on the intensive care unit? A concise systematic review

Background

There is a need for practical, efficient and effective prognostic markers for patients admitted to the intensive care unit (ICU) with sepsis, to identify patients at highest risk and guide and monitor treatment. Although many biomarkers and scoring systems have been advocated, none have yet achieved this elusive combination. Most ICUs already use blood lactate concentrations to monitor patients but the evidence base for this application is unclear.

Methods

A systematic review of the last five years of evidence of effectiveness of lactate measurement in prediction of outcome in ICUs was performed.

Results

It was found that there is a lack of high-quality evidence, and no specific studies of prognostic accuracy. d- or l-Lactate concentrations measured in plasma, serum, whole blood or colonic washings were raised at admission in almost all patient groups, and were higher in patient groups who had the worst outcomes (in-hospital mortality, sequential organ failure). However, there was significant overlap in individual concentrations measured in those who died within 28 days of admission, or who developed multiple organ failure, and those who did not. For serum l-lactate concentrations, no specific cut-off value capable of predicting in-hospital mortality or sequential organ failure could be recommended.

Conclusions

The evidence reviewed suggested that whole blood, plasma or serum lactate measurement could not provide specific prognostic information for individual patients. There may be a role for monitoring for normalization of serum d- or l-lactate concentrations during goal-directed therapy in the ICU but further good-quality studies are needed. Measurement of the d-lactate stereoisomer shows promise, such that further studies are warranted.

Adverse outcomes associated with delayed intensive care consultation in medical and surgical inpatients

PURPOSE

The impact of delay in obtaining an intensive care unit (ICU) consult from inpatient wards is unclear. The goal of this study was to examine the effect of time to ICU consult from medical and surgical wards on mortality and length of stay (LOS).

MATERIALS AND METHODS

This was a retrospective study of 241 adult medical and surgical inpatients admitted at 2 tertiary care ICUs in Canada between 2007 and 2009. Neither institution has medical emergency teams (METs). Patient demographics, time when the patient would have fulfilled MET calling criteria (MET time), time of ICU consult, and ICU admission were analyzed. The main outcome variables were 30-day mortality and ICU LOS.

RESULTS

Multivariate analysis demonstrated an increase in mortality (odds ratio, 1.8; 95% confidence interval, 1.1-2.9; P = .01) with increased duration from MET time to ICU consult for medical patients. There was no effect of this period on ICU LOS in medical patients. In contrast, in surgical patients, the MET time to ICU consult duration was associated with an increased ICU LOS (coefficient, 2.1 for delay; 95% confidence interval, 0.26-3.8; P = .02) but had no effect on mortality.

CONCLUSIONS

Increased duration to ICU consult from MET time is associated with adverse outcomes. These adverse outcomes are different between medical and surgical patients.

Application of Medical Information Systems for the detection of high risk patients: rapid care alerts. Pilot study of the ARA-Son Llàtzer Project

OBJECTIVE

To describe the implementation of a Medical Information System (MIS) in the Critical Care Departament (CCD).

DESIGN

A prospective observational cohort study was carried out.

SETTING

Clinical and Surgical wards in Son Llàtzer Hospital.

PATIENTS

Patients with criteria of rapid care alert (RCA) without treatment, cardiac arrest (CA), and unexpected ward deaths (UWD), during 2010.

MAIN VARIABLES

Age, sex, nursing shift, nursing alert, vital signs, unplanned admission to intensive care, CA, UWD and death.

RESULTS

The MIS detected 9647 episodes with RCA signs in 4020 patients (26.4 episodes/day). A total of 8547 episodes were reviewed. Sixty-five patients required rapid response by the intensive care staff; 61.5% were detected in the afternoon shift (15:00 a 22:00), and 61.5% were admitted to the CCD. Diminished consciousness (DC) and respiratory failure were the most frequent problems. The sepsis rate was 23%. We reviewed 45 CA and 35 UWD. Of the total cases of CA, 33 patients died (73.3%) and 66.7% had criteria of untreated RCA. Monitoring (P<.05) and rhythms amenable to defibrillation (P<.002) were associated to survival. As regards the UWD, 75% had criteria of untreated RCA, and 40.6% presented diminished consciousness. In the last 6 months there was a significant reduction in UWD (P=.01)

CONCLUSIONS

The MIS could be a complimentary tool in the activity of the CCD to improve the prognosis of hospitalized patients.

Early intervention on the outcomes in critically ill cancer patients admitted to intensive care units

PURPOSE

To determine whether earlier intervention was associated with decreased mortality in critically ill cancer patients admitted to an intensive care unit (ICU).

METHODS

A retrospective observational study was performed of 199 critically ill cancer patients admitted to the ICU from the general ward between January 2010 and December 2010. A logistic regression model was used to adjust for potential confounding factors in the association between time to intervention and in-hospital mortality.

RESULTS

In-hospital mortality was 52 %, with a median Simplified Acute Physiology Score 3 (SAPS 3) of 80 [interquartile range (IQR) 67-93], and a median Sequential Organ Failure Assessment (SOFA) score of 8 (IQR 5-11). Median time from physiological derangement to intervention (time to intervention) prior to ICU admission was 1.5 (IQR 0.6-4.3) h. Median time to intervention was significantly shorter in survivors than in non-survivors (0.9 vs. 3.0 h; p < 0.001). Additionally, the mortality rates increased significantly with increasing quartiles of time to intervention (p < 0.001, test for trend). Other factors associated with in-hospital mortality were severity of illness, performance status, hematologic malignancy, stem-cell transplantation, presence of three or more abnormal physiological variables, time from derangement to ICU admission, presence of infection, need for mechanical ventilation and vasopressor, and low PaO(2)/FiO(2) ratio. Even after adjusting for potential confounding factors, time to intervention was still significantly associated with hospital mortality (adjusted odds ratio 1.445, 95 % confidence interval 1.217-1.717).

CONCLUSIONS

Early intervention before ICU admission was independently associated with decreased in-hospital mortality in critically ill cancer patients admitted to the ICU.

Inhibition of vascular adenosine triphosphate-sensitive potassium channels by sympathetic tone during sepsis

OBJECTIVE

Excessive opening of the adenosine triphosphate-sensitive potassium channel in vascular smooth muscle is implicated in the vasodilation and vascular hyporeactivity underlying septic shock. Therapeutic channel inhibition using sulfonylurea agents has proved disappointing, although agents acting on its pore appear more promising. We thus investigated the hemodynamic effects of adenosine triphosphate-sensitive potassium channel pore inhibition in awake, fluid-resuscitated septic rats, and the extent to which these responses are modulated by the high sympathetic tone present in sepsis. Temporal changes in ex-vivo channel activity and subunit gene expression were also investigated.

DESIGN

In vivo and ex vivo animal study.

SETTING

University research laboratory.

SUBJECTS

Male adult Wistar rats.

INTERVENTIONS AND MEASUREMENTS

Fecal peritonitis was induced in conscious, fluid-resuscitated rats. Pressor responses to norepinephrine and PNU-37883A (a vascular adenosine triphosphate-sensitive potassium channel inhibitor acting on the Kir6.1 pore-forming subunit) were measured at 6 or 24 hrs, in the absence or presence of the autonomic ganglion blocker, pentolinium. The aorta and mesenteric artery were examined ex vivo for rubidium efflux as a marker of adenosine triphosphate-sensitive potassium channel activity, and for adenosine triphosphate-sensitive potassium channel subunit gene expression using quantitative reverse transcription-polymerase chain reaction.

MAIN RESULTS

A total of 120 rats (50 sham-operated controls, 70 septic) were included. Septic rats became hypotensive after 12 hrs, with a 24-hr mortality of 51.7% (0% in controls). At 6 hrs, there was an attenuated pressor response to norepinephrine (p < .01) despite blood pressure being elevated (p < .01). PNU-37883A had no pressor effect, except in the presence of pentolinium (p < .01). Kir6.1 subunit mRNA increased significantly in the mesenteric artery while rubidium efflux was increased in both the aorta and mesenteric artery at 24 hrs.

CONCLUSIONS

Despite evidence of increased adenosine triphosphate-sensitive potassium channel activity in sepsis, it appears to be inhibited in vivo by high sympathetic tone. This may explain, at least in part, the reduced efficacy of adenosine triphosphate-sensitive potassium channel blockers in human septic shock.

Defining impact of a rapid response team: qualitative study with nurses, physicians and hospital administrators

OBJECTIVE

The objective of this study was to qualitatively describe the impact of a Rapid Response Team (RRT) at a 944-bed, university-affiliated hospital.

METHODS

We analysed 49 open-ended interviews with administrators, primary team attending physicians, trainees, RRT attending hospitalists, staff nurses, nurses and respiratory technicians.

RESULTS

Themes elicited were categorised into the domains of (1) morale and teamwork, (2) education, (3) workload, (4) patient care, and (5) hospital administration. Positive implications beyond improved care for acutely ill patients were: increased morale and empowerment among nurses, real-time redistribution of workload for nurses (reducing neglect of non-acutely ill patients during emergencies), and immediate access to expert help. Negative implications were: increased tensions between nurses and physician teams, a burden on hospitalist RRT members, and reduced autonomy for trainees.

CONCLUSIONS

The RRT provides advantages that extend well beyond a reduction in rates of transfers to intensive care units or codes but are balanced by certain disadvantages. The potential impact from these multiple sources should be evaluated to understand the utility of any RRT programme.

Use of online blood volume and blood temperature monitoring during haemodialysis in critically ill patients with acute kidney injury: a single-centre randomized controlled trial

BACKGROUND

Little is known about the clinical impact on cardiovascular stability during intermittent haemodialysis (IHD) for acute kidney injury (AKI) of online monitoring devices that control blood volume (BV) and blood temperature in the intensive care unit (ICU) setting. We compared different dialysis treatment modalities with or without these new systems among critically ill patients requiring IHD.

METHODS

In a prospective single-centre three-arm randomized controlled trial, 600 dialysis sessions in 74 consecutive AKI critically ill patients were involved to assess intradialytic hypotension. Standard dialysis therapy with constant ultrafiltration (UF) rate, cool dialysate and high sodium conductivity (Treatment A) was compared to regimens with adjunctive interventions including BV control (Treatment B) and the combination of BV and active blood temperature control (Treatment C). Each dialysis session was randomly assigned to one of the three treatment arms and served as statistical unit.

RESULTS

Five hundred and seventy-two dialysis sessions were analysed (188, 190 and 194 in Treatments A, B and C, respectively). Hypotension occurred in 16.6% treatments, with similar rates among the arms. Haemodynamic parameters and dialysis-related complications did not differ between therapies. Based on generalized estimating equation adjusted to dialysate sodium conductivity, higher Sequential Organ Failure Assessment the day of dialysis session, the need for vasopressors and lower systolic blood pressure at the onset of the session were identified as independent predictors of hypotensive episodes, whereas regimens containing the new online monitors were not.

CONCLUSIONS

These results suggest that both actively controlled body temperature and UF profiled by online monitoring systems have no significant impact on the incidence of intradialytic hypotension in the ICU setting. Further research is needed before the use of these new sophisticated automatic methods can be applied routinely to the ICU setting.

The impact of diabetes on the pathogenesis of sepsis

Diabetes is associated with an increased susceptibility to infection and sepsis. Conflicting data exist on whether the mortality of patients with sepsis is influenced by the presence of diabetes, fuelling the ongoing debate on the benefit of tight glucose regulation in patients with sepsis. The main reason for which diabetes predisposes to infection appears to be abnormalities of the host response, particularly in neutrophil chemotaxis, adhesion and intracellular killing, defects that have been attributed to the effect of hyperglycaemia. There is also evidence for defects in humoral immunity, and this may play a larger role than previously recognised. We review the literature on the immune response in diabetes and its potential contribution to the pathogenesis of sepsis. In addition, the effect of diabetes treatment on the immune response is discussed, with specific reference to insulin, metformin, sulphonylureas and thiazolidinediones.

The sequential organ failure assessment (SOFA) score is prognostically superior to the model for end-stage liver disease (MELD) and MELD variants following paracetamol (acetaminophen) overdose

BACKGROUND

The prognostic value of the model for end-stage liver disease (MELD) and sodium-based MELD variants in predicting survival following paracetamol overdose remains unclear.

AIM

To examine the prognostic accuracy of sodium-based MELD variants in paracetamol-induced acute liver injury compared with the sequential organ failure assessment (SOFA) score.

METHODS

Retrospective analysis of 138 single time point paracetamol overdoses admitted to a tertiary liver centre. Individual laboratory samples were correlated with the corresponding clinical parameters in relation to time post-overdose, and the daily MELD, MELD-Na, MELDNa, MESO, iMELD, UKELD, updated MELD and SOFA scores were calculated.

RESULTS

Sixty-six (47.8%) patients developed hepatic encephalopathy, of whom 7 were transplanted and 21 died without liver transplantation. SOFA had a significantly greater area under the receiver operator characteristic for the prediction of spontaneous survival compared with MELD at both 72 (P = 0.024) and 96 (P = 0.017) h post-overdose. None of the sodium-based MELD variants improved the prognostic accuracy of MELD. A SOFA score >6 by 72 h or >7 by 96 h, post-overdose predicted death/transplantation with a negative predictive value of 96.9 (95% CI 90.2-99.4) and 98.8 (95% CI 93.6-99.9) respectively. SOFA and MELD had similar accuracy for predicting the development of hepatic encephalopathy (P = 0.493).

CONCLUSIONS

The SOFA score is superior to MELD in predicting spontaneous survival following paracetamol-induced acute liver injury. Modification of the MELD score to include serum sodium does not improve prognostic accuracy in this setting. SOFA may have potential as a quantitative triage marker following paracetamol overdose.

Prognostic value and agreement of achieving lactate clearance or central venous oxygen saturation goals during early sepsis resuscitation

OBJECTIVES

Lactate clearance (LC) and central venous oxygen saturation (ScvO(2)) have been proposed as goals of early sepsis resuscitation. The authors sought to determine the agreement and prognostic value of achieving ScvO(2) or LC goals in septic shock patients undergoing emergency department (ED)-based early resuscitation.

METHODS

This was a preplanned analysis of a multicenter ED randomized controlled trial of early sepsis resuscitation targeting three variables: central venous pressure, mean arterial pressure, and either ScvO(2) or LC. Inclusion criteria included suspected infection, two or more systemic inflammation criteria, and either systolic blood pressure of <90 mm Hg after intravenous fluid bolus or lactate level of >4 mmol/L. Both ScvO(2) and LC were measured simultaneously. The ScvO(2) goal was defined as ≥70%. Lactate was measured at enrollment and every 2 hours until the goal was reached or up to 6 hours. LC goal was defined as a decrease of ≥10% from initial measurement. The primary outcome was in-hospital mortality.

RESULTS

A total of 203 subjects were included, with an overall mortality of 19.7%. Achievement of the ScvO(2) goal only was associated with a mortality rate of 41% (9/22), while achievement of the LC goal only was associated with a mortality rate of 8% (2/25; proportion difference = 33%; 95% confidence interval [CI] = 9% to 55%). No agreement was found between goal achievement (κ = -0.02), and exact test for matched pairs demonstrated no significant difference between discordant pairs (p = 0.78).

CONCLUSIONS

No agreement was found between LC and ScvO(2) goal achievement in early sepsis resuscitation. Achievement of a ScvO(2) ≥ 70% without LC ≥ 10% was more strongly associated with mortality than achievement of LC ≥ 10% with failure to achieve ScvO(2) ≥ 70%.

Impact of single centre status on estimates of intervention effects in trials with continuous outcomes: meta-epidemiological study

OBJECTIVE

To compare estimates of intervention effects between single centre and multicentre randomised controlled trials with continuous outcomes.

DESIGN

Meta-epidemiological study.

DATA SOURCES

26 meta-analyses totalling 292 randomised controlled trials (177 single centre, 115 multicentre) with continuous outcomes published between January 2007 and January 2010 in the Cochrane database of systematic reviews.

DATA EXTRACTION

Data were extracted on characteristics of trials, single or multicentre status, risk of bias using the risk of bias tool of the Cochrane Collaboration, and results.

DATA SYNTHESIS

The intervention effects were estimated with standardised mean differences. For each meta-analysis, random effects meta-regression was used to estimate the difference in standardised mean differences between single centre and multicentre trials. Differences in standardised mean differences were then pooled across meta-analyses by a random-effects meta-analysis model. A combined difference in standardised mean differences of less than 0 indicated that single centre trials showed larger treatment effects, on average, than did multicentre trials. Because single centre trials may be more prone to publication bias and may have lower methodological quality than multicentre trials, sensitivity analyses were done with adjustment for sample size and domains of the risk of bias tool.

RESULTS

Single centre trials showed larger intervention effects than did multicentre trials (combined difference in standardised mean differences -0.09, 95% confidence interval -0.17 to -0.01, P=0.04), with low heterogeneity across individual meta-analyses (I(2)=0%, between meta-analyses variance τ(2)=0.00). Adjustment for sample size slightly attenuated the difference (-0.08, -0.17 to 0.01). Adjustment for risk of bias yielded similar estimates with wider confidence intervals, some of them crossing 0 (-0.09, -0.17 to 0.00 for overall risk of bias).

CONCLUSIONS

On average, single centre clinical trials with continuous outcomes showed slightly larger intervention effects than did multicentre trials. Further research is needed to investigate potential causes of these differences.

Mobilisation in critical care: a concept analysis

OBJECTIVES

The aim of this paper is to analyse the concept of mobilisation within the context of the critical care setting. Mobilisation is a widely used term that belies the complexity of its use in practice. Whilst facilitating movement is a significant nursing concern, mobilisation practices vary widely amongst nurses, perhaps due to conceptual incongruence.

METHODS

Evolutionary methodology was used in this concept analysis. Medline, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane Database of Systematic Reviews and PsycInfo databases were searched from 1966 to present. Search terms included mobilisation, mobility and passive exercise, yielding 61 articles suitable for analysis.

FINDINGS

Findings indicate that mobilisation is an interdisciplinary, goal-directed therapy used to facilitate movement and improve outcomes. It involves energy expenditure and has both physical and psychological domains. Disciplines vary in applications of mobilisation and therapy parameters are essentially undefined. The energy expenditure attribute has been well-exemplified in physical therapy literature, but only to a minimal degree in nursing literature.

CONCLUSION

In spite of the wide use of mobilisation, the concept requires further development, particularly in the critical care setting. Barriers to mobilisation require further delineation as does the psychological domain. Ongoing concept analysis can be used to inform practice and guide research activities.

Rapid response systems: identification and management of the "prearrest state"

Rapid response systems (RRS) are both intuitive and supported by data, but the institution of an RRS is not a panacea for in-hospital cardiac arrest or unexpected deaths. RRS implementation should be one component of an institution-wide effort to improve patient safety that includes adequate nursing education and staffing, availability and involvement of a patient's primary caregivers, and hospital provision of sufficient resources and efficiency.

Model for End-Stage Liver Disease score for predicting outcome in critically ill medical patients with liver cirrhosis

PURPOSE

We hypothesized that the Model for End-Stage Liver Disease (MELD) score at admission to the intensive care unit (ICU) can predict in-hospital mortality for patients with liver cirrhosis. We also tested the MELD-natremia (Na) score and compared the predictive value of the 2 models.

MATERIALS AND METHODS

This is a retrospective cohort study. A total of 441 consecutive patients with liver cirrhosis admitted to the ICU were included. The MELD and MELD-Na scores and other variables were obtained upon patients' admission to the ICU.

RESULTS

The area under the receiver operating characteristic curve to predict in-hospital mortality was 0.77 (95% confidence interval, 0.73-0.82) for the MELD score and 0.77 (95% confidence interval, 0.73-0.81) for the MELD-Na score.

CONCLUSION

The MELD scoring system provides useful prognostic information for critically ill patients with liver cirrhosis admitted to an ICU. The MELD and MELD-Na scores had similar predictive value.

Postoperative emergency response team activation at a large tertiary medical center

OBJECTIVE

To study characteristics and outcomes associated with emergency response team (ERT) activation in postsurgical patients discharged to regular wards after anesthesia.

PATIENTS AND METHODS

We identified all ERT activations that occurred within 48 hours after surgery from June 1, 2008, through December 31, 2009, in patients discharged from the postanesthesia care unit to regular wards. For each ERT case, up to 2 controls matched for age (±10 years), sex, and type of procedure were identified. A chart review was performed to identify factors that may be associated with ERT activation.

RESULTS

We identified 181 postoperative ERT calls, 113 (62%) of which occurred within 12 hours of discharge from the postanesthesia care unit, for an incidence of 2 per 1000 anesthetic administrations (0.2%). Multiple logistic regression analysis revealed the following factors to be associated with increased odds for postoperative ERT activation: preoperative central nervous system comorbidity (odds ratio [OR], 2.53; 95% confidence interval [CI], 1.20-5.32; P=.01), preoperative opioid use (OR, 2.00; 95% CI, 1.30-3.10; P=.002), intraoperative use of phenylephrine infusion (OR, 3.05; 95% CI, 1.08-8.66; P=.04), and increased intraoperative fluid administration (per 500-mL increase, OR, 1.06; 95% CI, 1.01-1.12; P=.03). ERT patients had longer hospital stays, higher complication rates, and increased 30-day mortality compared with controls.

CONCLUSION

Preoperative opioid use, history of central neurologic disease, and intraoperative hemodynamic instability are associated with postoperative decompensation requiring ERT intervention. Patients with these clinical characteristics may benefit from discharge to progressive or intensive care units in the early postoperative period.

Early potassium channel blockade improves sepsis-induced organ damage and cardiovascular dysfunction

BACKGROUND AND PURPOSE

There is increasing evidence that potassium channels are involved in the cardiovascular dysfunction of sepsis. This evidence was obtained after the systemic inflammation, cardiovascular dysfunction and organ damage had developed. Here we have studied the consequences of early interference with potassium channels on development of sepsis.

EXPERIMENTAL APPROACH

Sepsis was induced by caecal ligation and puncture (CLP) or sham surgery in Wistar rats. Four hours after surgery, animals received tetraethylammonium (TEA; a non-selective potassium channel blocker) or glibenclamide (a selective ATP-sensitive potassium channel blocker). Twenty-four hours after surgery, inflammatory, biochemical, haemodynamic parameters and survival were evaluated.

KEY RESULTS

Sepsis significantly increased plasma NO(x) levels, expression of inducible nitric oxide synthase (NOS-2) protein in lung and thigh skeletal muscle, lung myeloperoxidase, urea, creatinine and lactate levels, TNF-α and IL-1β, hypotension and hyporesponsiveness to phenylephrine and hyperglycemia followed by hypoglycemia. TEA injected 4 h after surgery attenuated the increased NOS-2 expression, reduced plasma NO(x) , lung myeloperoxidase activity, levels of TNF-α and IL-1β, urea, creatinine and lactate levels, prevented development of hypotension and hyporesponsiveness to phenylephrine, the alterations in plasma glucose and reduced late mortality by 50%. Glibenclamide did not improve any of the measured parameters and increased mortality rate, probably due to worsening the hypoglycemic phase of sepsis.

CONCLUSIONS AND IMPLICATIONS

Early blockade of TEA-sensitive (but not the ATP-sensitive subtype) potassium channels reduced organ damage and mortality in experimental sepsis. This beneficial effect seems to be, at least in part, due to reduction in NOS-2 expression.

Clinical review: use of venous oxygen saturations as a goal - a yet unfinished puzzle

Shock is defined as global tissue hypoxia secondary to an imbalance between systemic oxygen delivery and oxygen demand. Venous oxygen saturations represent this relationship between oxygen delivery and oxygen demand and can therefore be used as an additional parameter to detect an impaired cardiorespiratory reserve. Before appropriate use of venous oxygen saturations, however, one should be aware of the physiology. Although venous oxygen saturation has been the subject of research for many years, increasing interest arose especially in the past decade for its use as a therapeutic goal in critically ill patients and during the perioperative period. Also, there has been debate on differences between mixed and central venous oxygen saturation and their interchangeability. Both mixed and central venous oxygen saturation are clinically useful but both variables should be used with insightful knowledge and caution. In general, low values warn the clinician about cardiocirculatory or metabolic impairment and should urge further diagnostics and appropriate action, whereas normal or high values do not rule out persistent tissue hypoxia. The use of venous oxygen saturations seems especially useful in the early phase of disease or injury. Whether venous oxygen saturations should be measured continuously remains unclear. Especially, continuous measurement of central venous oxygen saturation as part of the treatment protocol has been shown a valuable strategy in the emergency department and in cardiac surgery. In clinical practice, venous oxygen saturations should always be used in combination with vital signs and other relevant endpoints.

Restrictive strategy of intraoperative fluid maintenance during optimization of oxygen delivery decreases major complications after high-risk surgery

Introduction

Optimal fluid management is crucial for patients who undergo major and prolonged surgery. Persistent hypovolemia is associated with complications, but fluid overload is also harmful. We evaluated the effects of a restrictive versus conventional strategy of crystalloid administration during goal-directed therapy in high-risk surgical patients.

Methods

We conducted a prospective, randomized, controlled study of high-risk patients undergoing major surgery. For fluid maintenance during surgery, the restrictive group received 4 ml/kg/hour and the conventional group received 12 ml/kg/hour of Ringer's lactate solution. A minimally invasive technique (the LiDCO monitoring system) was used to continuously monitor stroke volume and oxygen delivery index (DO₂I) in both groups. Dobutamine was administered as necessary, and fluid challenges were used to test fluid responsiveness to achieve the best possible DO₂I during surgery and for 8 hours postoperatively.

Results

Eighty-eight patients were included. The patients' median age was 69 years. The conventional treatment group received a significantly greater amount of lactated Ringer's solution (mean ± standard deviation (SD): 4, 335 ± 1, 546 ml) than the restrictive group (mean ± SD: 2, 301 ± 1, 064 ml) (P < 0.001). Temporal patterns of DO₂I were similar between the two groups. The restrictive group had a 52% lower rate of major postoperative complications than the conventional group (20.0% vs 41.9%, relative risk = 0.48, 95% confidence interval = 0.24 to 0.94; P = 0.046).

Conclusions

A restrictive strategy of fluid maintenance during optimization of oxygen delivery reduces major complications in older patients with coexistent pathologies who undergo major surgery.

Trial registration

ISRCTN: ISRCTN94984995

Randomized clinical trial of fluid restriction in colorectal surgery

BACKGROUND

Perioperative fluid therapy can influence postoperative hospital stay and complications after elective colorectal surgery. This trial was designed to examine whether an extremely restricted perioperative fluid protocol would reduce hospital stay beyond the existing fast-track hospital time of 7 days after surgery.

METHODS

Patients were randomized to restricted or standard perioperative intravenous fluid regimens in a single-centre trial. Randomization was stratified for colonic, rectal, open and laparoscopic surgery. Patients were all treated within a fast-track protocol (careful preoperative preparation, optimal analgesia, early oral nutrition and early mobilization). The primary endpoint was length of postoperative hospital stay. The secondary endpoint was complications within 30 days.

RESULTS

Seventy-nine patients were randomized to restricted and 82 to standard fluid therapy. Patients in the restricted group received a median of 3050 ml fluid on the day of surgery compared with 5775 ml in the standard group (P < 0·001). There was no difference between groups in primary hospital stay (median 6·0 days in both groups; P = 0·194) or stay including readmission (median 6·0 days in both groups; P = 0·158). The proportion of patients with complications was significantly lower in the restricted group (31 of 79 versus 47 of 82; P = 0·027). Vasopressors were more often required in the restricted group (97 versus 80 per cent; P < 0·001).

CONCLUSION

Restricted perioperative intravenous fluid administration does not reduce length of stay in a fast-track protocol.

Consideration of donor age and human leukocyte antigen matching in the setting of multiple potential living kidney donors

BACKGROUND

Defining living donor (LD)-related risk factors affecting kidney transplant outcome will allow better donor selection and more educated informed consent when there is more than one potential donor. We studied risk factors in a large cohort at a single institution.

METHODS

We reviewed 1632 recipients who underwent LD kidney transplantation at the University of Minnesota between January 1, 1990, and October 1, 2009. Using Cox regression, we studied the effect of donor and recipient risk factors on patient and graft survival. We specifically examined the effect of donor age and human leukocyte antigen (HLA) matching because these are variables that may help clinical decision making when multiple potential donors exist.

RESULTS

Mean donor age was 40.6 years for all transplants; 180 (11%) donors were 55 years or older, and 24 (1.5%) donors were older than 65 years. Mean number of HLA mismatches (per transplant) was 2.9 (29.2% of recipients had one to two HLA mismatches, 39.8% had three to four HLA mismatches, and 25% had five to six HLA mismatches). Donor age more than 65 years, five to six HLA mismatches, delayed graft function, and acute rejection were independent predictors of decreased patient and graft survival. When controlling for recipient age, donor age more than 65 years remained a risk factor for worse outcome.

CONCLUSIONS

Our data suggest that advanced donor age (>65 years) and degree of HLA mismatch (≥5) are independent donor-related risk factors associated with worse outcome. When multiple potential LDs exist, it may be ideal to attempt to use a donor younger than 65 years and with less than five HLA mismatches.

The validation of a clinical algorithm for the prevention and management of pulmonary dysfunction in intubated adults--a synthesis of evidence and expert opinion

BACKGROUND

Pulmonary dysfunction (PDF) in intubated patients remains a serious and costly complication of intensive care unit care. Optimal cardiopulmonary therapy strategies to prevent and manage PDF need clarification to reduce practice variability. The purpose of this paper is to report on the content validation of an evidence-based clinical management algorithm (EBCMA) aimed at the prevention, identification and management of PDF in critically ill patients.

METHODS

Forty-four draft algorithm statements extracted from the extant literature by the primary research team were verified and rated by research clinicians (n = 7) in an electronic three-round Delphi process. Statements which reached a priori defined consensus [semi-interquartile range (SIQR) <0.5] were collated into the EBCMA.

RESULTS

One hundred per cent response rate. Forty-four statements were added after round one. Consensus was reached on rating of 83% (73/88) statements. Differences in interpretation of the existing evidence base, and variations in accepted clinical practice were identified. Four themes were identified where panel failed to reach consensus.

CONCLUSION

The internationally agreed hierarchical framework of current available evidence and clinical expertise developed through this Delphi process provides clinicians with a tool to inform clinical practice. This tool has the potential to reduce practice variability thereby maximizing safety and treatment outcome. The clinical utility of the EBCMA requires further evaluation.

Acute-on-chronic liver failure: current concepts on definition, pathogenesis, clinical manifestations and potential therapeutic interventions

In recent years, acute-on-chronic liver failure has been recognized as a specific clinical form of liver failure associated with cirrhosis. The syndrome refers to an acute deterioration of liver function and subsequently of other end organs over a period of weeks following a precipitating event in a patient with previously well- or reasonably well-compensated cirrhosis. These precipitating events include either an indirect (e.g., variceal hemorrhage, sepsis) or a direct (e.g., drug-induced) hepatotoxic factor. The short-term mortality for this condition is more than 50%. At present, considerable efforts are ongoing to better characterize the syndrome, to gain further insight into its pathophysiology and to optimize therapy. This article aims to highlight the current concepts of these various aspects.

Mortality after thermal injury: no sex-related difference

BACKGROUND

Young women have been reported to be more likely to survive than men after severe trauma. Girls also have less inflammation and hypermetabolism after major burns. Yet burned women have been found to have a twofold greater risk of death than men. Our aim was to find out if there is a sex-related difference in mortality after thermal injury, particularly in the age group between 16 years and 49 years, when hormonal differences would be most influential.

METHODS

All patients admitted to the Linköping University Hospital Burn Unit with thermal injuries during the years 1993-2008 were included and the variables percentage burned total body surface area (TBSA%), age, type of burn, mechanical ventilation, and year were included in a multiple regression (Poisson log) model.

RESULTS

Of 1,119 patients with thermal injury, 792 (71%) were men. Crude mortality was 5% among men, and 8% among women (p = 0.04). After adjustment for age and TBSA%, there was no correlation between mortality and sex, in any age group. Eight men and four women died in the group of young adults (16-49 years) in which TBSA% correlated with mortality (p < 0.01) but age did not. Mortality was 14% (32 of 221) among the men and 23% (23 of 102) of women in the group of older adults (50 years and older), and both age and TBSA% correlated with mortality (p < 0.001).

CONCLUSIONS

There is no relevant sex-related difference in survival after thermal injury. The conclusion is, however, tempered by the few deaths, particularly among younger adults.

Sepsis-induced tissue hypoperfusion

The understanding of sepsis is continuously evolving. An overview of sepsis-induced tissue hypoperfusion has been provided herein. It is of critical importance that the clinician understands the pathophysiology of this emergent condition and is able to synthesize the available data in a rapid fashion so that tissue hypoperfusion is readily detected. Once detected, aggressive and endpoint-directed resuscitation should be implemented to reverse the hypoperfusion and to prevent further deterioration, organ dysfunction, and death.