Critical Care - Latest articles

Readmission to a surgical intensive care unit: incidence, outcome, and risk factors

2008-10-06

IntroductionWe investigated the incidence of, outcome from, and possible risk factors for readmission to our surgical intensive care unit (ICU). Methods: Analysis of prospectively collected data from all patients admitted to the postoperative ICU between September 2004 and July 2006. Results: Of 3169 patients admitted to our ICU during the study period, 2852 were discharged to the hospital floor and constituted the study group (1828 male (64.1%), mean age 62 years). The readmission rate was 13.4% (n = 381): 314 (82.4%) readmitted once, 39 (10.2%) readmitted twice, and 28 (7.3%) readmitted more than twice. The first readmission to the ICU occurred within a median of 7 (5-14) days. Patients who were readmitted to the ICU had higher simplified acute physiology II (37+/-16 versus 33+/-16, p <0.001) and sequential organ failure (6+/-3 versus 5+/-3, p = 0.001) scores on initial admission to the ICU than those who were not readmitted. In-hospital mortality was significantly higher in patients readmitted to the ICU (17.1 versus 2.9 %, p <0.001) than in other patients. In a multivariate analysis, age (odds ratio: 1.13 per 10 years, 95% confidence interval: 1.03 - 1.24, p = 0.04), maximum sequential organ failure score (odds ratio: 1.04 per point, 95% confidence interval: 1.01 - 1.08, p = 0.04), and C-reactive protein levels on the day of discharge to the hospital floor (odds ratio: 1.02, 95% confidence interval: 1.01 - 1.04, p = 0.035) were independently associated with a higher risk of readmission to the ICU. Conclusions: In this group of surgical ICU patients, readmission to the ICU was associated with a more than 5-fold increase in hospital mortality. Older age, higher maximum sequential organ failure score and higher C-reactive protein levels on the day of discharge to the hospital floor were independently associated with a higher risk of readmission to the ICU.

The "cardiac-lung mass" artifact: an echocardiographic sign of lung atelectasis and/or pleural effusion

2008-09-30

IntroductionWe performed an ultrasound study to investigate echocardiographic artifacts in mechanically ventilated patients with lung pathology. Methods: Two hundred and five mechanically ventilated patients who exhibited lung atelectasis and/or pleural effusion participated in this 36-month study. Subjects underwent lung echography and transthoracic echocardiography with a linear 5 to 10 MHz and with a 1.5 to 3.6 MHz wide-angle phased-array transducer, respectively. Patients were examined by two experienced observers blinded to each other's interpretation. Results: One hundred and twenty four patients (60,48%) were hospitalised due to multiple trauma; 60 patients (29,26%) due to respiratory insufficiency, and 21 (10,24%) due to recent postoperative surgery. The mean period of hospitalisation was 35+/-27 days. An intracardiac artifact was documented in 17 out of 205 patients (8,29%) by echocardiography. It was visible only in the apical views, while subsequent transesophageal echocardiography revealed no abnormalities. The artifact consisted of a mobile component that demonstrated, on M-mode, a pattern of respiratory variation similar to the lung 'sinusoid sign'. Lung echography revealed lung atelectasis, and/or pleural effusion adjacent to the heart, and a similar M-mode pattern was observed. The artifact was recorded within the left cardiac chambers (11 cases) and within the right cardiac chambers (6 cases). Conclusions: Lung atelectasis and/or pleural effusion may create a mirror image, intracardiac artifact in mechanically ventilated patients. The latter was named as the "cardiac-lung mass" artifact to underline the important diagnostic role of both echocardiography and lung echography in these patients.

Using MRI of the optic nerve sheath to detect elevated intracranial pressure

Heidi Harbison Kimberly and Vicki E Noble — 2008-09-24

The current gold standard for the diagnosis of elevated intracranial pressure (ICP) remains invasive monitoring. Given that invasive monitoring is not always available or clinically feasible, there is growing interest in non-invasive methods of assessing ICP using diagnostic modalities such as ultrasound or magnetic resonance imaging (MRI). Increased ICP is transmitted through the cerebrospinal fluid surrounding the optic nerve, causing distention of the optic nerve sheath diameter (ONSD). In this issue of Critical Care, Geeraerts and colleagues describe a non-invasive method of diagnosing elevated ICP using MRI to measure the ONSD. They report a positive correlation between measurements of the ONSD on MRI and invasive ICP measurements. If the findings of this study can be replicated in larger populations, this technique may be a useful non-invasive screening test for elevated ICP in select populations.

Gastrointestinal dysfunction in the critically ill: can we measure it?

Rachel G Khadaroo and John C Marshall — 2008-09-24

Gastrointestinal dysfunction is an intuitively important, yet descriptively elusive component of the multiple organ dysfunction syndrome. Reintam and colleagues have attempted to quantify this dimension using a combination of intolerance of enteral feeding, and the development of intra-abdominal hypertension. While they show that both parameters are associated with an increased risk of death (and therefore that, in combination, the risk of death is even greater), they fall short in developing a novel descriptor of gastrointestinal dysfunction. Nonetheless, and even with its shortcomings, their effort is a welcome contribution to the surprisingly complex process of describing the morbidity of critical illness.

Anticoagulant therapy in acute lung injury: a useful tool without proper operating instruction?

Sebastian Rehberg, Perenlei Enkhbaatar and Daniel L Traber — 2008-09-22

Activation of the coagulation cascade resulting in alveolar fibrin deposition is recognized as a hallmark of acute lung injury (ALI). Anticoagulant treatment with recombinant human activated protein C (rhAPC) appears promising, because – like in sepsis – there is a deficiency of protein C in ALI, which is correlated with poor outcome in both syndromes. Recently in Critical Care, Waerhaug and colleagues confirmed the beneficial effects of rhAPC on pulmonary function in ovine endotoxin-induced ALI. Notably, the authors reported no differences in hemorrhage in histologic analyses between rhAPC-treated and untreated animals. However, a recently reported randomized, placebo-controlled, multicenter trial in ALI patients without severe sepsis failed to identify any differences in the number of ventilator-free days or 60 day-mortality between the rhAPC and placebo group. In addition to (or perhaps because of) the complex pathogenesis, the discrepancy between clinical and experimental results in ALI is another common feature with sepsis. The future challenge will be to transfer our theoretical knowledge adequately into daily clinical practice. Anticoagulant therapy might be a useful tool in the treatment of ALI; however the proper operating instruction remains to be defined.

Intensive care for the adult population in Ireland: a multicentre study of intensive care population demographics

The Irish Critical Care Trials Group — 2008-09-18

IntroductionThis prospective observational study was designed to describe the nature of the intensive care population across Ireland, identify adherence to international benchmarks of practice, and describe patient outcomes for critically ill patients. Methods: A prospective observational multicentre study of demographics and organ failure incidence was carried out over a 10 week period in 2006 across the intensive care units (ICUs) of 14 hospitals in both the Republic and Northern Ireland Results: In total, there were 1029 patient episodes entered across 14 ICUs. Emergency admissions accounted for 70% of episodes. Admissions post major elective surgery accounted for 20.5% of admissions. The mean length of ICU stay was 5.7 days, with a median of 2 days. Severe sepsis was identified in 35% of patients during their ICU admission. Mechanical ventilation was used in 70.7% of all patients admitted, of whom 26.9% had acute lung injury. Acute kidney injury occurred in 28% of all patients. Inter-hospital transfers were undertaken for 85 (8.3%) patients. The overall intensive care mortality of the study population was 19%. Conclusions: Intensive care medicine in Ireland serves a patient population with a high requirement for mechanical ventilation and support of the function of multiple organs. The overall mortality compares favourably with international benchmarks.

Strict glycaemic control in patients hospitalised in a mixed medical and surgical intensive care unit: a randomised clinical trial

2008-09-17

IntroductionCritically ill patients can develop hyperglycaemia even if they do not have diabetes. Intensive insulin therapy decreases morbidity and mortality rates in patients in a surgical intensive care unit (ICU) and decreases morbidity in patients in a medical ICU. The effect of this therapy on patients in a mixed medical/surgical ICU is unknown. Our goal was to assess whether the effect of intensive insulin therapy, compared with standard therapy, decreases morbidity and mortality in patients hospitalised in a mixed ICU. Methods: This is a prospective, randomised, non-blinded, single-centre clinical trial in a medical/surgical ICU. Patients were randomly assigned to receive either intensive insulin therapy to maintain glucose levels between 80 and 110 mg/dl (4.4 to 6.1 mmol/l) or standard insulin therapy to maintain glucose levels between 180 and 200 mg/dl (10 and 11.1 mmol/l). The primary end point was mortality at 28 days. Results: Over a period of 30 months, 504 patients were enrolled. The 28-day mortality rate was 32.4% (81 of 250) in the standard insulin therapy group and 36.6% (93 of 254) in the intensive insulin therapy group (Relative Risk [RR]: 1.1; 95% confidence interval [CI]: 0.85 to 1.42). The ICU mortality in the standard insulin therapy group was 31.2% (78 of 250) and 33.1% (84 of 254) in the intensive insulin therapy group (RR: 1.06; 95%CI: 0.82 to 1.36). There was no statistically significant reduction in the rate of ICU-acquired infections: 33.2% in the standard insulin therapy group compared with 27.17% in the intensive insulin therapy group (RR: 0.82; 95%CI: 0.63 to 1.07). The rate of hypoglycaemia (≤ 40 mg/dl) was 1.7% in the standard insulin therapy group and 8.5% in the intensive insulin therapy group (RR: 5.04; 95% CI: 1.20 to 21.12). Conclusions: IIT used to maintain glucose levels within normal limits did not reduce morbidity or mortality of patients admitted to a mixed medical/surgical ICU. Furthermore, this therapy increased the risk of hypoglycaemia.Trial Registrationclinicaltrials.gov Identifiers: 4374-04-13031; 094-2 in 000966421

Entropy and Bispectral Index for the assessment of sedation, analgesia and effects of unpleasant stimuli in critically ill patients: an observational study

2008-09-16

IntroductionSedative and analgesic drugs are frequently used in critically ill patients. Overuse of such drugs may prolong mechanical ventilation and length of stay in the intensive care unit. Guidelines recommend the use of sedation protocols with sedation scores and sedation stops to minimize drug use. This study evaluated processed electroencephalography (response and state entropy and bispectral index) as an adjunct for monitoring of effects of commonly used sedative and analgesic drugs and intra-tracheal suctioning. Methods: Electrodes for monitoring bispectral index and entropy were placed on the foreheads of 44 critically ill patients with need for mechanical ventilation and absence of previous brain dysfunction. Sedation was targeted individually with the Ramsay sedation scale, which was recorded at least at 2-hour intervals. Use of and indication for sedative and analgesic drugs and intra-tracheal suctioning were recorded manually and with a camera. At the end of the study, processed electroencephalography and hemodynamic variables collected before and after each drug application and tracheal suctioning were analyzed. Ramsay score was used for comparison with processed electroencephalography when assessed within 15 minutes of an intervention. Results: Various indications for sedation boli have statistically significant, but clinically irrelevant differences in processed electroencephalography parameters. Electroencephalography variables decreased significantly after the bolus, but a specific pattern of the electroencephalography variables before drug administration was not shown. The same is true for opiate administration. At both 30 minutes and two minutes before intra-tracheal suctioning, there was no difference in electroencephalography or clinical signs in patients who had or had not received drugs 10 minutes before suctioning. Patients receiving drugs returned faster to their baseline values. In the cases where Ramsay score was assessed prior to the event, processed electroencephalography showed a high variation. Conclusions: Unpleasant or painful stimuli and use of sedative and analgesic drugs are associated with significant changes in processed electroencephalogram (EEG) parameters. However, clinical indications for drug administration were not reflected by these electroencephalogram parameters, and were hardly reflected by sedation level before drug administration or tracheal suction. This precludes incorporating Entropy and BIS as target variables for sedation and analgesia protocols in critically ill patients.

Circuit lifespan during continuous renal replacement therapy: children and adults are not equal

Zaccaria Ricci, Isabella Guzzo, Stefano Picca and Sergio Picardo — 2008-09-16

In the field of continuous renal replacement therapy (CRRT), session length, downtime and dose require detailed research, which will provide information important in relation to prescription, anticoagulation and circuit material choice (membrane type and size, vascular access site and size). In particular, it appears that many of the data currently existing in the literature and accepted regarding CRRT prescription and delivery in critically ill adult patients are not strictly applicable to the paediatric setting. Furthermore, many of the available paediatric studies are small, retrospective or underpowered. In paediatric CRRT, epidemiological investigations and prospective trials to investigate practical aspects of extracorporeal therapies are welcome and urgently needed.

Analysis of N-terminal pro-B-type natriuretic peptide and cardiac index in multiple injured patients: a prospective cohort study

2008-09-12

IntroductionIncreased serum B-type naturietic peptide (BNP) has been identified for diagnosis and prognosis of impaired cardiac function in patients suffering from congestive heart failure, ischemic heart disease and sepsis. However, the prognostic value of BNP in multiple injured patients developing multiple organ dysfunction (MODS) remains undetermined, so far. Therefore, the aim of this study was to assess N-terminal pro-B-type natriuretic peptide (NT-proBNP) in multiple injured patients, and to correlate the results with invasively assessed cardiac output and clinical signs of MODS. Methods: Twenty six multiple injured patients presenting a new injury severity score (NISS) >16 points were included. The MODS score was calculated on admission, as well as 24, 48 and 72 hours after injury. Patients were subdivided: group A with minor signs of organ dysfunction (MODS less than or equal to 4 points) and group B suffering from major organ dysfunction (MODS >4 points). 5mL of venous blood were collected after admission, 6, 12, 24, 48, and 72 hours after injury. NT-proBNP was determined using Elecsys proBNP(R) assay. The hemodynamic monitoring of cardiac index (CI) was performed using transpulmonary thermodilution. Results: Serum NT-proBNP levels were elevated in all 26 patients. At admission, the serum NT-proBNP was 116+/-21pg/ml in group A versus 209+/-93pg/ml in group B. NT-proBNP was significantly lower at all following time points in group A in comparison to group B (p <0.001). In contrast, the CI in group A was significantly higher than in group B at all time points (p <0.001). Concerning MODS and CI at 24, 48 and 72 hours after injury, an inverse correlation was found (r = -0.664, p <0.001). Furthermore a correlation was found comparing MODS score and serum NT-proBNP levels (r = 0.75, p <0.0001) Conclusions: Serum NT-proBNP levels significantly correlate with clinical signs of MODS 24 hours after multiple injury. Furthermore, a distinct correlation of serum NT-proBNP and decreased CI was found. The data of this pilot study may indicate a potential value of NT-proBNP in diagnosis of posttraumatic cardiac impairment. However, further studies are needed to elucidate this issue.