Diagnostic utility of B-type natriuretic peptide in critically ill patients with pulmonary edema: a prospective cohort study

Introduction

Distinguishing pulmonary edema due to acute lung injury (ALI) or the acute respiratory distress syndrome (ARDS) from hydrostatic or cardiogenic edema is challenging in critically ill patients. B-type natriuretic peptide (BNP) can effectively identify congestive heart failure in the emergency room setting but, despite increasing use, its diagnostic utility has not been validated in the intensive care unit (ICU).

Methods

We performed a prospective, blinded cohort study in the medical and surgical ICUs at the University of Chicago Hospitals. Patients were eligible if they were admitted to the ICU with respiratory distress, bilateral pulmonary edema and a central venous catheter suggesting either high-pressure (cardiogenic) or low-pressure (ALI/ARDS) pulmonary edema. BNP levels were measured within 48 hours of ICU admission and development of pulmonary edema and onward up to three consecutive days. All levels were drawn simultaneously with the measurement of right atrial or pulmonary artery wedge pressure. The etiology of pulmonary edema – cardiogenic or ALI/ARDS – was determined by three intensivists blinded to BNP levels.

Results

We enrolled a total of 54 patients (33 with ALI/ARDS and 21 with cardiogenic edema). BNP levels were lower in patients with ALI/ARDS than in those with cardiogenic edema (496 ± 439 versus 747 ± 476 pg/ml, P = 0.05). At an accepted cutoff of 100 pg/ml, specificity for the diagnosis of ALI/ARDS was high (95.2%) but sensitivity was poor (27.3%). Cutoffs at higher BNP levels improved sensitivity at considerable cost to specificity. Invasive measures of filling pressures correlated poorly with initial BNP levels and subsequent day BNP values fluctuated unpredictably and without correlation with hemodynamic changes and net fluid balance.

Conclusion

BNP levels drawn within 48 hours of admission to the ICU do not reliably distinguish ALI/ARDS from cardiogenic edema, do not correlate with invasive hemodynamic measurements, and do not track predictably with changes in volume status on consecutive daily measurements.     

Factors associated with anxiety in critically ill patients: A prospective observational cohort study

BackgroundAnxiety is an unpleasant emotion that most intensive care patients experience. This emotion is an important issue in intensive care settings because of its prevalence, adverse effects and severity. Little is known about the factors associated with state and trait anxiety during critical illness.ObjectivesTo describe the patterns of state anxiety reported by intensive care patients, and identify factors associated with state and trait anxiety.DesignProspective observational cohort study.SettingsOne mixed intensive care unit in Brisbane, Australia.ParticipantsAdults (n = 141, ≥18 years) admitted to the intensive care unit for ≥24 h; able to communicate verbally or non-verbally; understand English; and, open their eyes spontaneously or in response to voice.MethodsOutcomes were state anxiety as measured by the Faces Anxiety Scale and trait anxiety as measured by the State-Trait Anxiety Inventory. Pre-intensive care factors tested for possible associations with both state and trait anxiety were: age, gender, marital status, employment status, level of education, smoking status, personality trait of optimism and evidence of mental health care/treatment. Intra-intensive care factors tested were: reason for admission to the intensive care unit, delirium, pain, airway status, hours of mechanical ventilation, severity of illness, days of stay in intensive care, exposure to corticosteroids, opioids, benzodiazepines, anxiolytics, antidepressants, beta-blockers, anaesthetic agents and analgesics; length of sedation and analgesia and total doses of sedatives and analgesics.ResultsOf 141 participants, 98 (70%) were male with an average age of 54 (standard deviation: ±15) years and stayed in intensive care for about 4 (Interquartile Range: 3–7) days. The majority (n = 115; 82%) of participants experienced state anxiety at least once during their stay in intensive care, with 57% reporting moderate to severe levels. Factors related to state anxiety in intensive care were pain and trait anxiety. Factors associated with trait anxiety were trait optimism, state anxiety, evidence of mental health care/treatment and age.ConclusionsThis study provides a better understanding of contributing factors for anxiety in the critically ill. Trait anxiety and state anxiety were significantly associated with each other, namely, patients who were anxious by nature experienced higher levels of state anxiety, which persisted throughout their stay in the intensive care unit. Recognising the importance of state and trait anxiety assessments using validated tools and determining ways to manage anxiety in the critically ill are critical aspects of the intensive care nurses role.     

Ciprofloxacin pharmacokinetics in critically ill patients: a prospective cohort study

Purpose

Optimal dosing of antibiotics is important for efficacy and avoidance of resistance. Fluoroquinolones are frequently used to treat severe infections in critically ill patients. We studied ciprofloxacin pharmacokinetics after administration of 400 mg twice a day (bid) intravenously (IV).

Material and methods

Serum concentrations were measured in 32 intensive care unit patients (age, 68.7 ± 17.4 years; Sepsis-related Organ Failure Assessment (SOFA) scores, 7.3 ± 3.4). Blood samples were drawn at 7 time points after ciprofloxacin infusion. We evaluated whether areas under the curve (AUCs) exceeded minimal inhibitory concentration (MIC) values of 0.125, 0.25, 0.5, 1.0, and 2.0 mg/L by 125 times and peak concentrations (C_max) 10 × MIC (C_max/MIC >10).

Results

The AUC/MIC more than 125 was achieved in 100% for MIC 0.125. For MIC values 0.25, 0.5, 1.0, and 2.0, results were 84%, 31%, 3%, and 0%, respectively (P < .01). The C_max/MIC more than 10 for MIC values of 0.125, 0.25, 0.5, 1.0, and 2.0 was realized in 100%, 97%, 69%, 25%, and 0%, respectively (P < .01). Female sex, SOFA_pulmonary points, and SOFA_renal points predicted higher AUC. Cumulative SOFA scores were most predictive of high AUCs.

Conclusions

Ciprofloxacin 400 mg bid IV leads to inadequate AUC/MIC and C_max/MIC ratios in many cases. Effective killing concentrations were only achieved in pathogens with MIC less than 0.25. As bacteria in intensive care unit patients often exceed this threshold, we recommend to use higher doses of ciprofloxacin (1200 mg daily) to ensure optimal bacterial killing and avoid antibiotic resistance.     

Gastrointestinal failure score in critically ill patients: a prospective observational study

Introduction

There are no universally accepted diagnostic criteria for gastrointestinal failure in critically ill patients. In the present study we tested whether the occurrence of food intolerance (FI) and intra-abdominal hypertension (IAH), combined in a 5-grade scoring system for assessment of gastrointestinal function (the Gastrointestinal Failure [GIF] score), predicts mortality. The prognostic value of the GIF score alone and in combination with the Sequential Organ Failure Assessment (SOFA) score is evaluated, and the incidence and outcome of gastrointestinal failure is described relative to the GIF score.

Methods

A total of 264 subsequently hospitalized patients, who were mechanically ventilated on admission and stayed in the intensive care unit (ICU) for longer than 24 hours, were prospectively studied. GIF score was documented daily as follows: 0 = normal gastrointestinal function; 1 = enteral feeding with under 50% of calculated needs or no feeding 3 days after abdominal surgery; 2 = FI or IAH; 3 = FI and IAH; and 4 = abdominal compartment syndrome (ACS). Admission parameters and mean GIF and SOFA scores for the first 3 days were used to predict ICU outcome.

Results

FI developed in 58.3%, IAH in 27.3%, and both together in 22.7% of patients. The mean GIF score for the first 3 days in the ICU was identified as an independent risk factor for mortality (odds ratio = 3.02, 95% confidence interval = 1.63 to 5.59; P < 0.001). The GIF score integrated into the SOFA score allowed better prediction of ICU mortality than did the SOFA score alone, and was an independent predictor of mortality (odds ratio = 1.49, 95% confidence interval = 1.28 to 1.74; P < 0.001). The development of gastrointestinal failure (FI plus IAH) was associated with significantly higher ICU and 90-day mortality.

Conclusion

The GIF score is useful for classifying information on the gastrointestinal system. The mean GIF score during the first 3 days in the ICU had high prognostic value for ICU mortality. Development of gastrointestinal failure is associated with significantly impaired outcome.     

Incidence and short-term consequences of delirium in critically ill patients: A prospective observational cohort study

BackgroundDelirium is a serious and frequent psycho-organic disorder in critically ill patients. Reported incidence rates vary to a large extent and there is a paucity of data concerning delirium incidence rates for the different subgroups of intensive care unit (ICU) patients and their short-term health consequences.ObjectivesTo determine the overall incidence and duration of delirium, per delirium subtype and per ICU admission diagnosis. Furthermore, we determined the short-term consequences of delirium.DesignProspective observational study.Participants and settingAll adult consecutive patients admitted in one year to the ICU of a university medical centre.MethodsDelirium was assessed using the Confusion Assessment Method-ICU three times a day. Delirium was divided in three subtypes: hyperactive, hypoactive and mixed subtype. As measures for short-term consequences we registered duration of mechanical ventilation, re-intubations, incidence of unplanned removal of tubes, length of (ICU) stay and in-hospital mortality.Results1613 patients were included of which 411 (26%) developed delirium. The incidence rate in the neurosurgical (10%) and cardiac surgery group (12%) was the lowest, incidence was intermediate in medical patients (40%), while patients with a neurological diagnosis had the highest incidence (64%). The mixed subtype occurred the most (53%), while the hyperactive subtype the least (10%). The median delirium duration was two days [IQR 1–7], but significantly longer (P < 0.0001) for the mixed subtype. More delirious patients were mechanically ventilated and for a longer period of time, were more likely to remove their tube and catheters, stayed in the ICU and hospital for a longer time, and had a six times higher chance of dying compared to non-delirium ICU patients, even after adjusting for their severity of illness score. Delirium was associated with an extended duration of mechanical ventilation, length of stay in the ICU and in-hospital, as well as with in-hospital mortality.ConclusionsThe delirium incidence in a mixed ICU population is high and differs importantly between ICU admission diagnoses and the subtypes of delirium. Patients with delirium had a significantly higher incidence of short-term health problems, independent from their severity of illness and this was most pronounced in the mixed subtype of delirium. Delirium is significantly associated with worse short-term outcome.     

Erythropoietin response in critically ill mechanically ventilated patients: a prospective observational study

Introduction

Anemia is a common problem in critically ill patients. The etiology of anemia of critical illness is often determined to be multifactorial in the clinical setting, but the pathophysiology remains to be elucidated. Erythropoietin (EPO) is an endogenous glycoprotein hormone that serves as the primary stimulus for erythropoiesis. Recent evidence has demonstrated a blunted EPO response as a factor contributing to anemia of critical illness in specific subsets of patients. Critically ill patients requiring mechanical ventilation who exhibit anemia have not been the subject of previous studies. Our goal was to evaluate the erythropoietic response to anemia in the critically ill mechanically ventilated patient.

Methods

A prospective observational study was undertaken in the medical intensive care unit of a tertiary care, military hospital. Twenty patients admitted to the medical intensive care unit requiring mechanical ventilation for at least 72 hours were enrolled as study patients. EPO levels and complete blood count were measured 72 hours after admission and initiation of mechanical ventilation. Admission clinical and demographic data were recorded, and patients were followed for the duration of mechanical ventilation. Twenty patients diagnosed with iron deficiency anemia in the outpatient setting were enrolled as a control population. Control patients had baseline complete blood count and iron panel recorded by primary care physicians. EPO levels were measured at the time of enrollment in conjunction with complete blood count.

Results

The mean EPO level for the control population was 60.9 mU/ml. The mean EPO level in the mechanically ventilated patient group was 28.7 mU/ml, which was significantly less than in the control group (P = 0.035). The mean hemoglobin value was not significantly different between groups (10.6 g/dl in mechanically ventilated patients versus 10.2 g/dl in control patients; P > 0.05).

Conclusion

Mechanically ventilated patients demonstrate a blunted EPO response to anemia. Further study of therapies directed at treating anemia of critical illness and evaluating its potential impact on mechanical ventilation outcomes and mortality is warranted.

     

Accidental catheter removal in critically ill patients: a prospective and observational study

Introduction  

The importance of accidental catheter removal (ACR) lies in the complications caused by the removal itself and by catheter reinsertion. To the best of our knowledge, no studies have analyzed accidental removal of various types of catheters in the intensive care unit (ICU). The objective of the present study was to analyze the incidence of ACR for all types of catheters in the ICU.     

Antiphospholipid antibodies in critically ill patients with cancer: A prospective cohort study

Purpose

The purpose of this study is to evaluate the prevalence and the prognostic impact of antiphospholipid antibodies (aPL) in critically ill cancer patients.

Methods

This is a prospective cohort study in adult patients admitted to the intensive care unit for more than 48 hours at a cancer center. Clinical and laboratory data including coagulation parameters were obtained. Cox proportional hazard models were used to identify predictors of 6-month mortality.

Results

Ninety-five (solid tumor, 79%; hematologic malignancies, 21%) patients were included, and aPL were identified in 74% of them. Median Simplified Acute Physiology Score 3 and Sequential Organ Failure Assessment scores were 51 (37-65) and 5 (2-8) points, respectively. The most frequent aPL were lupus anticoagulant (61%) and anti-β2 glicoprotein I (32%). Vascular complications occurred in 18% of patients and were comparable between aPL + and aPL − patients. Sepsis and need for renal replacement therapy were more frequent in aPL + patients. Hospital and 6-month mortality rates were 44% and 56%, respectively. Higher Sequential Organ Failure Assessment scores (each point) (hazard ratios [HR] = 2.83 [95% confidence interval, 1.59-5.00]), medical admissions (HR = 2.66 [1.34-5.27]), and d-dimer more than 500 ng/dL (HR = 1.89 (1.04-3.44]) were independently associated with mortality. After adjusting for these covariates, aPL status was not associated with outcomes (HR = 1.22 [0.60-2.47]).

Conclusions

Lupus anticoagulants were frequent in critically ill cancer patients. However, they were not associated with medium-term survival in these patients.     

Variability of linezolid concentrations after standard dosing in critically ill patients: a prospective observational study

Introduction

Severe infections in intensive care patients show high morbidity and mortality rates. Linezolid is an antimicrobial drug frequently used in critically ill patients. Recent data indicates that there might be high variability of linezolid serum concentrations in intensive care patients receiving standard doses. This study was aimed to evaluate whether standard dosing of linezolid leads to therapeutic serum concentrations in critically ill patients.

Methods

In this prospective observational study, 30 critically ill adult patients with suspected infections received standard dosing of 600 mg linezolid intravenously twice a day. Over 4 days, multiple serum samples were obtained from each patient, in order to determine the linezolid concentrations by liquid chromatography tandem mass spectrometry.

Results

A high variability of serum linezolid concentrations was observed (range of area under the linezolid concentration time curve over 24 hours (AUC₂₄) 50.1 to 453.9 mg/L, median 143.3 mg*h/L; range of trough concentrations (C_min) < 0.13 to 14.49 mg/L, median 2.06 mg/L). Furthermore, potentially subtherapeutic linezolid concentrations over 24 hours and at single time points (defined according to the literature as AUC₂₄ < 200 mg*h/L and C_min < 2 mg/L) were observed for 63% and 50% of the patients, respectively. Finally, potentially toxic levels (defined as AUC₂₄ > 400 mg*h/L and C_min > 10 mg/L) were observed for 7 of the patients.

Conclusions

A high variability of linezolid serum concentrations with a substantial percentage of potentially subtherapeutic levels was observed in intensive care patients. The findings suggest that therapeutic drug monitoring of linezolid might be helpful for adequate dosing of linezolid in critically ill patients.

Trial registration

Clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01793012","term_id":"NCT01793012"}}NCT01793012. Registered 24 January 2013.     

The impact of frailty in critically ill patients after trauma: A prospective observational study

BackgroundAs our population ages, older adults are increasingly exposed to trauma. Frailty could be a useful measure to identify patients at risk of a poor outcome. This study aimed to determine the impact of frailty in an Australian trauma intensive care unit (ICU) population.MethodsA prospective observational study of critically ill trauma patients ≥50 years of age. Frailty was determined on admission to the ICU using the frailty phenotype. Demographic and hospital data were collected, and patients were followed up at 6 and 12 months. The primary outcome was 12-month mortality, and multiple regression was used to determine associated factors.ResultsOne hundred thirty-eight patients were included, whose mean age was 68 years; 78.2% (108/138) were classified as major trauma (Injury Severity Score >12). Twenty-two percent (30/138) of patients were identified as frail. Patients with frailty were significantly older: however, they were less severely injured and required lower rates of surgical interventions and mechanical ventilation. Frailty was independently associated with mortality at 6 and 12 months (odds ratio: 5.9, 95% confidence interval: 1.9–18.1 and odds ratio: 7.3, 95% confidence interval: 2.5–21.9, respectively). Patients with frailty had lower measures of global functioning (Glasgow Outcome Scale-Extended frail 3 [1–5] vs nonfrail 6 [(5–7], p = 0.002) and health status (Euro Qol 5Q-5D-5L utility score 0.6 [0.5–0.7] vs 0.7 [0.6–0.9], p = 0.02) at 12 months than patients without frailty.ConclusionFrailty is a useful predictor of poor outcomes in critically ill trauma patients.Registration of protocol numberACTRN12615000039583.     

Impact of polyurethane on variations in tracheal cuff pressure in critically ill patients: a prospective observational study

Objective  

To determine the impact of polyurethane (PU) on variations in cuff pressure (P _cuff) in intubated critically ill patients.     

Impact of positive fluid balance on critically ill surgical patients: A prospective observational study

Purpose

The purpose of this study is to determine the effect of postoperative fluid balance (FB) on subsequent outcomes in acute care surgery (ACS) patients admitted to the surgical intensive care unit (ICU).

Material and methods

Acute care surgery patients admitted to the surgical ICU from 06/2012 to 01/2013 were followed up prospectively. Patients were stratified by FB into FB-positive (+) and FB-negative (−) groups by surgical ICU day 5 or day of discharge from the surgical ICU.

Results

A total of 144 ACS patients met inclusion criteria. Although there was no statistically significant difference in crude mortality (11% for FB [−] vs 15.5% for FB [+]; P = .422], after adjusting for confounding factors, achieving an FB (−) status by day 5 during the surgical ICU stay was associated with an almost 70% survival benefit (adjusted odds ratio [95% confidence interval], 0.31 [0.13, 0.76]; P = .010). In addition, achieving a fluid negative status by day 1 provided a protective effect for both overall and infectious complications (adjusted odds ratio [95% confidence interval], 0.63 [0.45, 0.88]; P = .006 and 0.64 [0.46, 0.90]; P = .010, respectively).

Conclusions

In a cohort of critically ill ACS patients, achieving FB (−) status early during surgical ICU admission was associated with a nearly 70% reduction in the risk for mortality.