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.

BACKGROUND:In this study we quantify the ability of dynamic cardiovascular parameters measured by the PulseCO™ algorithm of the LiDCO™plus monitor to predict the response to a fluid challenge in post-operative patients. METHODS:Surgical patients, admitted to the Intensive Care Unit from the operating theatre were monitored with the LiDCO™plus system. A number of static and dynamic cardiovascular measurements were recorded before and after a fluid challenge. Receiver Operator Characteristic (ROC) curve analysis was used to identify the baseline values, with optimum sensitivity and specificity, to predict responsiveness to a fluid challenge. RESULTS:Thirty-one patients were enrolled, and received protocol-based fluid challenges. Twelve (38%) responded by demonstrating an increase in stroke volume of >15%. Heart rate (HR) and central venous pressure (CVP) were not statistically different between responders and non-responders. Mean arterial pressure (mAP), systolic pressure variation (SPV), pulse pressure variation (PPV) and stroke volume variation (SVV) were statistically different between responders and non-responders. Parameters with a ROC area under the curve (AUC) significantly >0.5 included SPV 0.70 (0.52-0.88) P=0.046, PPV 0.87 (0.76-0.99) P<0.0002 and SVV 0.84 (0.71-0.96) P=0.0005. The best cut-off values (sensitivity and specificity) to predict fluid were SPV >9 mmHg (73%, 76%), PPV >13% (83%, 74%) and SVV >12.5% (75%, 83%). ROC analysis did not show the AUC to be significantly >0.5 for HR, mAP and CVP CONCLUSION: Dynamic indices measured by PulseCO™ (LiDCO) have a high sensitivity and specificity in predicting fluid responsiveness in sedated and mechanically ventilated patients. A cut-off value for PPV of 13% is the most sensitive and specific indicator of fluid responsiveness.

Assays of cardiac troponin have become a cornerstone in the diagnosis of myocardial infarction across a broad range of clinical settings. In critically ill patients, cardiac troponin is detectable in the plasma in up to 60% of cases, and this incidence may increase further as assays become more sensitive. Troponin rises in critical care are commonly unrelated to pathology in the coronary arteries, but are frequently associated with conditions such as sepsis and respiratory failure. Such non-coronary troponin release is a significant, independent predictor of poor patient outcomes, and can be incorporated into risk scoring systems. Despite adding prognostic value, treatment for non-coronary troponin rises remains limited to management of the underlying cause, and restoration of a favourable balance between myocardial oxygen demand and supply. Conversely, troponin rises secondary to myocardial infarctions are amenable to the same interventions as in any other setting, albeit with additional diagnostic and therapeutic challenges. In this review, we will explore the utility of troponin as a biomarker in critical care, and we will outline a pragmatic management strategy for this patient population.

BACKGROUND Recent work suggests that increased plasma concentrations of cardiac troponin I (cTnI) are common in critically ill patients and are associated with poor outcome. We measured the frequency of increased plasma cTnI concentrations during patients' stay in a mixed medical/surgical intensive care unit (ICU) and compared our findings with hospital mortality. METHODS Basic details, organ support, and hospital mortality were recorded for all patients treated in ICU during a 6 month period. cTnI concentrations were sampled daily for all patients, using 0.04 µg litre(-1) as the upper limit of normal, and 0.12 µg litre(-1) as an additional stratification point. RESULTS Of 663 patients, 54% were male, with a mean (sd) age of 60 (18) yr, 65% were surgical patients, and the median Acute Physiology and Chronic Ill Health II (APACHE II) score was 15 (inter-quartile range 12-20). Increased cTnI concentrations were found in 345 patients (52%) while in ICU. One hundred and twenty patients (18%) died in hospital. cTnI concentration >0.04 µg litre(-1) was associated with reduced odds of hospital survival, independent of age, medical admission, unplanned admission, APACHE II score, mechanical ventilation, and haemofiltration (adjusted odds ratio 0.25, 95% confidence interval 0.08-0.75, P=0.014). Stratification by the degree of cTnI increase revealed an incremental trend towards a lower odds of hospital survival, including for patients with 'minor' elevations of cTnI (0.05-0.12 µg litre(-1)). CONCLUSIONS Increased serum cTnI concentrations during ICU stay independently predicts hospital mortality, even when the threshold is low. We found a trend towards an association between 'minor' elevations in cTnI and higher in-hospital mortality.

Perioperative fluid management remains controversial. Nevertheless, its optimization is essential to reducing the risk of postoperative complications, which have been shown to profoundly affect patients' short- and long-term outcomes. Current evidence favors a "flow-guided" approach to perioperative fluid administration, which uses variables such as stroke volume and cardiac output as the basis for guiding fluid requirements. The optimal fluid is controversial, although colloids appear to have some physiologic advantages over crystalloids. Minimally invasive technologies have emerged for intraoperative monitoring of blood flow, which may enable more precise fluid titration.

General anaesthesia is usually the preferred technique, but spinal anaesthesia has many advantages in day-case surgery. It is easy to perform, has a rapid onset of action, blocks only the region being operated on, and provides good muscle relaxation and early postoperative analgesia. Spinal anaesthesia limits postanaesthetic nursing care, is less expensive and reduces the nausea and vomiting associated with general anaesthesia. However, day-case spinal anaesthesia remains controversial because of concerns over postdural puncture headache, backache and delayed micturition while prolonged motor blockade may preclude early mobilization and discharge.