Owen Boyd

How is risk defined in high-risk surgical patient management?

The definition of risk in surgical patients is a complex and controversial area. Generally risk is poorly understood and depends on past individual and professional perception, and societal norms. In medical use the situation is further complicated by practical considerations of the ease with which risk can be measured; and this seems to have driven much risk assessment work, with a focus on objective measurements of cardiac function. The usefulness of risk assessment and the definition of risk is however in doubt because there are very few studies that have materially altered patient outcome based on information gained by risk assessment. This paper discusses these issues, highlights areas where more research could usefully be performed, and by defining limits for high surgical risk, suggests a practical approach to the assessment of risk using risk assessment tools.

Follicular fluid levels of midazolam, fentanyl, and alfentanil during transvaginal oocyte retrieval.

OBJECTIVE To investigate the time course of changes in follicular fluid (FF) concentrations of midazolam (Roche Products Ltd., Welwyn Garden City, United Kingdom), fentanyl (Janssen Pharmaceuticals Ltd., Wantage, United Kingdom), and alfentanil (Janssen Pharmaceuticals Ltd.) during ultrasound-guided transvaginal oocyte collection. STUDY DESIGN Forty-five patients with tubal infertility were randomized to receive a bolus IV dose of midazolam, fentanyl, or alfentanil for sedation during ultrasound-guided transvaginal oocyte collection. Paracervical block with lignocaine was given for analgesia. Simultaneous blood and FF samples were drawn at 5-minute intervals after the bolus dose for analysis of drug levels. RESULTS Data were obtained on 15 women receiving midazolam and fentanyl and on 13 women receiving alfentanil. Plasma levels of all agents rose to a peak and then fell in an exponential fashion as was expected. The FF levels of the agents continued to rise significantly to 25 minutes after the bolus dose, although the absolute level was low when compared with the blood level. There were no significant differences in fertilization or pregnancy rates in the three groups, but patient numbers were small. CONCLUSION We conclude that midazolam, fentanyl, and alfentanil are found in FF after a single IV dose, but further investigation needs to be undertaken to investigate any potential influence on fertilization and implantation rates.

A European, multicenter, observational study to assess the value of gastric-to-end tidal Pco(2) difference in predicting postoperative complications

Automated online tonometry displays a rapid, semi-continuous measurement of gastric-to-endtidal carbon dioxide (Pr-etCO2) as an index of gastrointestinal perfusion during surgery. Its use to predict postoperative outcome has not been studied in general surgery patients. We, therefore, studied ASA physical status III–IV patients operated on for elective surgery under general anesthesia and a planned duration of >2 h in a European, multicenter study. As each center was equipped with only 1 tonometric monitor, a randomization was performed if more than one patient was eligible the same day. Patients not monitored with tonometry were assessed only for follow-up. The main outcome measure was the assessment of postoperative functional recovery delay (FRD) on day 8. Among the 290 patients studied, 34% had FRD associated with a longer hospital stay. The most common FRDs were gastrointestinal (45%), infection (39%), and respiratory (35%). In those monitored with tonometry (n =179), maximum Pr-etCO2 proved to be the best predictor increasing the probability of FRD from 34% for all patients to 65% at a cut-off of 21 mm Hg (2.8kPa) (sensitivity 0.27, specificity 0.92, positive predictive value 64%, negative predictive value 70%). We conclude that intraoperative Pr-etCO2 measurement may be a useful prognostic index of postoperative morbidity.

Serum proteins modulate lipopolysaccharide and lipoteichoic acid-induced activation and contribute to the clinical outcome of sepsis

Bacterial cell wall components, such LPS and LTA, are potent initiators of an inflammatory response that can lead to septic shock. The advances in the past were centered around membrane-bound receptors and intracellular events, but our understanding of the initial interactions of these bacterial components with serum proteins as they enter the bloodstream remain unclear. In this study we identified several serum proteins, which are involved in the innate recognition of bacterial products. Using affinity chromatography and mass spectrometry we performed proteomic analysis of LPS- and LTA-binding serum proteins. We isolated proteins from normal serum that can interact with LPS and LTA. Fluorescent binding experiments and cytokine assays revealed that serum proteins, such as apolipoprotein, LDL, transferrin and holotransferrin could neutralize LPS/LTA binding as well as the subsequent inflammatory response, suggesting that serum proteins modulate LPS/LTA-induced responses. When compared with the proteomic profile of serum from septic patients it was shown that these proteins were in lower abundance. Investigation of serum proteins in 25 critically ill patients with a mortality rate of 40% showed statistically higher levels of these proteins in survivors. Patients surviving sepsis had statistically significant higher levels of apolipoprotein, albumin, LDL, transferrin and holotransferrin than individuals that succumbed, suggesting that these proteins have an inhibitory effect on LPS/LTA-induced inflammatory responses and in their absence there might be an augmented inflammatory response in sepsis.

Quality of life and persisting symptoms in intensive care unit survivors: implications for care after discharge

BackgroundWe assessed the quality of life of ICU survivors using SF-36 at 4 months after ICU discharge and investigated any correlation of PCS and MCS with age, illness severity and hospital or ICU length of stay. We examined the relationship between these variables, persisting physical and psychological symptoms and the perceived benefit of individual patients of follow-up.FindingsFor one year, adult patients admitted for multiple organ or advanced respiratory support for greater than 48 hours to a 16-bedded teaching hospital general intensive care unit were identified. Those surviving to discharge were sent a questionnaire at 4 months following ICU discharge assessing quality of life and persisting symptoms. Demographic, length of stay and illness severity data were recorded. Higher or lower scores were divided at the median value. A two-tailed Students t-test assuming equal variances was used for normally-distributed data and Mann-Whitney tests for non-parametric data.87 of 175 questionnaires were returned (50%), but only 65 had sufficient data giving a final response rate of 37%. Elderly patients had increased MCS as compared with younger patients. The PCS was inversely related to hospital LOS. There was a significant correlation between the presence of psychological and physical symptoms and desire for follow-up.ConclusionYounger age and prolonged hospital stay are associated with lower mental or physical quality of life and may be targets for rehabilitation. Patients with persisting symptoms at 4 months view follow-up as beneficial and a simple screening questionnaire may identify those likely to attend outpatient services.

A haemocompatible and scalable nanoporous adsorbent monolith synthesised using a novel lignin binder route to augment the adsorption of poorly removed uraemic toxins in haemodialysis.

Nanoporous adsorbents are promising materials to augment the efficacy of haemodialysis for the treatment of end stage renal disease where mortality rates remain unacceptably high despite improvements in membrane technology. Complications are linked in part to inefficient removal of protein bound and high molecular weight uraemic toxins including key marker molecules albumin bound indoxyl sulphate (IS) and p-cresyl sulphate (PCS) and large inflammatory cytokines such as IL-6. The following study describes the assessment of a nanoporous activated carbon monolith produced using a novel binder synthesis route for scale up as an in line device to augment haemodialysis through adsorption of these toxins. Small and large monoliths were synthesised using an optimised ratio of lignin binder to porous resin of 1 in 4. Small monoliths showing combined significant IS, p-CS and IL-6 adsorption were used to measure haemocompatibility in an ex vivo healthy donor blood perfusion model, assessing coagulation, platelet, granulocyte, T cells and complement activation, haemolysis, adsorption of electrolytes and plasma proteins. The small monoliths were tested in a naive rat model and showed stable blood gas values, blood pressure, blood biochemistry and the absence of coagulopathies. These monoliths were scaled up to a clinically relevant size and were able to maintain adsorption of protein bound uraemic toxins IS, PCS and high molecular weight cytokines TNF-α and IL-6 over 240 min using a flow rate of 300 ml min-1 without platelet activation. The nanoporous monoliths where haemocompatible and retained adsorptive efficacy on scale up with negligible pressure drop across the system indicating potential for use as an in-line device to improve haemodialysis efficacy by adsorption of otherwise poorly removed uraemic toxins.

Sedation practice: is it time to wake up and embrace change?

Recommendations for sedation regimes in the intensive care unit (ICU) have evolved over the last decade based on findings that relate the clinical approach to improved patient outcomes. Martin and co-workers conducted two surveys into German sedation practice covering the time period during which these changes occurred and as such provide an insight into how these recommendations are being incorporated into everyday clinical practice.

A snapshot summary of consultant cover and current working practices in Intensive Care Medicine across the United Kingdom

A challenge lies ahead in ensuring that consultant workforce planning within Intensive Care Medicine meets changing and expanding health care needs at a time of financial constraint. During the development of an enlarging consultant intensivist workforce, it is important to explore existing practices to ensure subsequent contracts provide optimal work intensity and on-call frequency as well as appropriate SPA time for clinical governance and professional development. We conducted a survey across 14 deaneries, 43 ICUs and 398 consultant job plans to compare current working practices and set these against new guidelines and standards. It demonstrated that 93% of consultants work 10 PAs or more, with an average of 5.14 Direct Clinical Care PAs in Intensive Care and an average of 2.14 SPAs. Seven of 43 ICUs had consultant-to-patient ratios greater than 1:8 and 33 ICUs had insufficient resident cover overnight, highlighting challenges with trainee staffing and anticipated service reconfiguration.

Haemodynamic optimisation: are we dynamic enough?

Perioperative haemodynamic optimisation of high-risk surgical patients has long been documented to improve both short-term and long-term outcomes, as well as to reduce the rate of postoperative complications. Based on the evidence, cardiac output monitoring and fluid resuscitation, combined with the use of inotropes, would seem to be the gold standard of care for these difficult surgical cases. However, clinicians do not universally apply these techniques and principles in their everyday practice. By exploring the reasons why this is so, perhaps we could move forward in the standardisation of care and the application of evidence-based practice.

Computer says 2.5 litres – how best to incorporate intelligent software into clinical decision making in the intensive care unit?

What will be the role of the intensivist when computer-assisted decision support reaches maturity? Celis group reports that Bayesian theory can predict a patients fluid requirement on day 2 in 78% of cases, based on data collected on day 1 and the known associations between those data, based on observations in previous patients in their unit. There are both advantages and limitations to the Bayesian approach, and this test study identifies areas for improvement in future models. Although such models have the potential to improve diagnostic and therapeutic accuracy, they must be introduced judiciously and locally to maximize their effect on patient outcome. Efficacy is thus far undetermined, and these novel approaches to patient management raise new challenges, not least medicolegal ones.