A Rhodes

The strong ion gap does not have prognostic value in critically ill patients in a mixed medical/surgical adult ICU

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

A prospective study of the use of a dobutamine stress test to identify outcome in patients with sepsis, severe sepsis, or septic shock

OBJECTIVE To more clearly define the relationship between an oxygen flux test, oxygen supply dependency, and outcome in patients with sepsis, severe sepsis, or septic shock. DESIGN Prospective, interventional clinical trial. SETTING A teaching hospital general intensive care unit in London, UK. PATIENTS A total of 36 patients with sepsis, severe sepsis, or septic shock were studied during a 10-month period. INTERVENTIONS After resuscitation, patients were given an intravenous infusion of dobutamine at 10 microg/kg/min for 1 hr. Cardiac and respiratory variables were measured before the infusion and then while the infusion was in progress. Any patient who was able to increase his or her oxygen consumption by >15% was designated a responder to the test. MEASUREMENTS AND MAIN RESULTS Hemodynamic, oxygen transport, and lactate measurements were made at baseline and after 1 hr of the dobutamine infusion. All patients were then followed up until hospital discharge. Responders to this test had a hospital mortality of 14%, whereas nonresponders had a mortality of 91% (p<.01). The responders were characterized by being younger (p<.05), having higher Acute Physiology and Chronic Health Evaluation III scores (p<.05), and having a greater requirement for inotropic support (p<.05). After the test, the responders had significantly higher oxygen delivery (p<.01) and oxygen consumption (p<.05) than the nonresponders, as well as a significantly greater temperature increase as a result of the infusion (p<.05). The nonresponders were unable to increase either oxygen delivery or oxygen consumption to the dobutamine. This test was highly predictive of outcome (p<.0001). The identification of an increase in both oxygen delivery and oxygen consumption (oxygen supply dependency) was not associated with a poor outcome. CONCLUSION A dobutamine oxygen flux test provides evidence of the intrinsic function of cells. The inability of these cells to increase oxidative metabolism during sepsis, as indicated by the dobutamine test, is associated with a high mortality.

Cardiac complications associated with goal-directed therapy in high-risk surgical patients: a meta-analysis

Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95% confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR=0.54, (0.38-0.76), P=0.0005] and arrhythmias [OR=0.54, (0.35-0.85), P=0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR=0.69, (0.43-1.10), P=0.12] or myocardial ischaemia [OR=0.70, (0.38-1.28), P=0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.

Severity assessment tools in ICU patients with 2009 Influenza A (H1N1) pneumonia

The aim of this study was to determine if severity assessment tools (general severity of illness and community-acquired pneumonia specific scores) can be used to guide decisions for patients admitted to the intensive care unit (ICU) due to pandemic influenza A pneumonia. A prospective, observational, multicentre study included 265 patients with a mean age of 42 (±16.1) years and an ICU mortality of 31.7%. On admission to the ICU, the mean pneumonia severity index (PSI) score was 103.2 ± 43.2 points, the CURB-65 score was 1.7 ± 1.1 points and the PIRO-CAP score was 3.2 ± 1.5 points. None of the scores had a good predictive ability: area under the ROC for PSI, 0.72 (95% CI, 0.65-0.78); CURB-65, 0.67 (95% CI, 0.59-0.74); and PIRO-CAP, 0.64 (95% CI, 0.56-0.71). The PSI score (OR, 1.022 (1.009-1.034), p 0.001) was independently associated with ICU mortality; however, none of the three scores, when used at ICU admission, were able to reliably detect a low-risk group of patients. Low risk for mortality was identified in 27.5% of patients using PIRO-CAP, but above 40% when using PSI (I-III) or CURB65 (<2). Observed mortality was 13.7%, 13.5% and 19.4%, respectively. Pneumonia-specific scores undervalued severity and should not be used as instruments to guide decisions in the ICU.

Hemodynamic Effect of Different Doses of Fluids for a Fluid Challenge: A Quasi-Randomized Controlled Study.

Objective: The objectives of this study are to determine what is the minimal volume required to perform an effective fluid challenge and to investigate how different doses of IV fluids in an fluid challenge affect the changes in cardiac output and the proportion of responders and nonresponders. Design: Quasi-randomized controlled trial. Setting: Cardiothoracic ICU, tertiary university hospital. Patients: Eighty postcardiac surgery patients. Intervention: IV infusion of 1, 2, 3, or 4 mL/Kg (body weight) of crystalloid over 5 minutes. Measurements and Main Results: Mean systemic filling pressure measured using the transient stop-flow arm arterial-venous equilibrium pressure, arterial and central venous pressure, cardiac output (LiDCOplus; LiDCO, Cambridge, United Kingdom), and heart rate. The groups were well matched with respect to demographic and baseline physiologic variables. The proportion of responders increased from 20% in the group of 1 mL/kg to 65% in the group of 4 mL/kg (p = 0.04). The predicted minimal volume required for an fluid challenge was between 321 and 509 mL. Only 4 mL/Kg increases transient stop-flow arm arterial-venous equilibrium pressure beyond the limits of precision and was significantly associated with a positive response (odds ratio, 7.73; 95% CI, 1.78–31.04). Conclusion: The doses of fluids used for an fluid challenge modify the proportions of responders in postoperative patients. A dose of 4 mL/Kg increases transient stop-flow arm arterial-venous equilibrium pressure and reliably detects responders and nonresponders.

EuSOS: European surgical outcomes study.

From Queen Mary’s University of London (RMP), St George’s Hospital (AR), London, UK, Hospital de Santo António dos Capuchos, Lisbon, Portugal (RM), University of Insubria, Varese, Italy (PP), Charité Universitätsmedizin, Berlin, Germany (CS), Centre Hospitalier Universitaire de Lille, Lille, France (BV), Medizinische Universität Wien, Vienna, Austria (PM, PB) and Erasme University Hospital, Brussels, Belgium (J-LV)

Tracheal dilatation complicating prolonged tracheal intubation

A patient with severe acute respiratory distress syndrome requiring prolonged tracheal intubation and mechanical ventilation is described. Tracheal dilatation was noted to have occurred following an elective surgical tracheostomy. Eventually, the patient was successfully weaned from mechanical ventilation and the tracheostomy tube removed.

Prognostic factors in intensive care

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

The Role of Dexmedetomidine in Intensite Care

The US Food and Drug Administration (FDA) first approved dexmedetomidine in December 1999 for use as a continuous infusion in post-operative ventilated patients for up to 24 hours in the intensive care unit (ICU). It is not yet approved in the European Union. Its use is currently being evaluated in a number of different situations: Longer-term use, perioperative care, anesthesia, and postoperative analgesia. This chapter will focus on its potential for intensive care patients.

From Arterial Pressure to Cardiac Output

There are a number of companies that market devices for the monitoring of cardiac output from the arterial pressure waveform. These devices all share a number of characteristics that need to be understood if they are to be used appropriately. This chapter aims to describe the underlying history and physics behind these computer based algorithms.