The future of UK healthcare: problems and potential solutions to a system in crisis

The UK's Health System is in crisis, central funding no longer keeping pace with demand. Traditional responses-spending more, seeking efficiency savings or invoking market forces-are not solutions. The health of our nation demands urgent delivery of a radical new model, negotiated openly between public, policymakers and healthcare professionals. Such a model could focus on disease prevention, modifying health behaviour and implementing change in public policy in fields traditionally considered unrelated to health such as transport, food and advertising. The true cost-effectiveness of healthcare interventions must be balanced against the opportunity cost of their implementation, bolstering the central role of NICE in such decisions. Without such action, the prognosis for our healthcare system-and for the health of the individuals it serves-may be poor. Here, we explore such a new prescription for our national health.

The effect of neoadjuvant chemotherapy and chemoradiotherapy on exercise capacity and outcome following upper gastrointestinal cancer surgery: an observational cohort study

Background

In 2014 approximately 21,200 patients were diagnosed with oesophageal and gastric cancer in England and Wales, of whom 37 % underwent planned curative treatments. Potentially curative surgical resection is associated with significant morbidity and mortality. For operable locally advanced disease, neoadjuvant chemotherapy (NAC) improves survival over surgery alone. However, NAC carries the risk of toxicity and is associated with a decrease in physical fitness, which may in turn influence subsequent clinical outcome. Lower levels of physical fitness are associated with worse outcome following major surgery in general and Upper Gastrointestinal Surgery (UGI) surgery in particular. Cardiopulmonary exercise testing (CPET) provides an objective assessment of physical fitness. The aim of this study is to test the hypothesis that NAC prior to upper gastrointestinal cancer surgery is associated with a decrease in physical fitness and that the magnitude of the change in physical fitness will predict mortality 1 year following surgery.

Methods

This study is a multi-centre, prospective, blinded, observational cohort study of participants with oesophageal and gastric cancer scheduled for neoadjuvant cancer treatment (chemo- and chemoradiotherapy) and surgery. The primary endpoints are physical fitness (oxygen uptake at lactate threshold measured using CPET) and 1-year mortality following surgery; secondary endpoints include post-operative morbidity (Post-Operative Morbidity Survey (POMS)) 5 days after surgery and patient related quality of life (EQ-5D-5 L).

Discussion

The principal benefits of this study, if the underlying hypothesis is correct, will be to facilitate better selection of treatments (e.g. NAC, Surgery) in patients with oesophageal or gastric cancer. It may also be possible to develop new treatments to reduce the effects of neoadjuvant cancer treatment on physical fitness. These results will contribute to the design of a large, multi-centre trial to determine whether an in-hospital exercise-training programme that increases physical fitness leads to improved overall survival.

Trial registration

ClinicalTrials.gov NCT01325883 - 29^th March 2011.

Systemic oxygen extraction during exercise at high altitude

Background

Classic teaching suggests that diminished availability of oxygen leads to increased tissue oxygen extraction yet evidence to support this notion in the context of hypoxaemia, as opposed to anaemia or cardiac failure, is limited.

Methods

At 75 m above sea level, and after 7–8 days of acclimatization to 4559 m, systemic oxygen extraction [C(a−v)O₂] was calculated in five participants at rest and at peak exercise. Absolute [C(a−v)O₂] was calculated by subtracting central venous oxygen content (CcvO₂) from arterial oxygen content (CaO2) in blood sampled from central venous and peripheral arterial catheters, respectively. Oxygen uptake (V˙O2) was determined from expired gas analysis during exercise.

Results

Ascent to altitude resulted in significant hypoxaemia; median (range) SpO2 87.1 (82.5–90.7)% and PaO2 6.6 (5.7–6.8) kPa. While absolute C(a−v)O₂ was reduced at maximum exercise at 4559 m [83.9 (67.5–120.9) ml litre⁻¹vs 99.6 (88.0–151.3) ml litre⁻¹ at 75 m, P=0.043], there was no change in oxygen extraction ratio (OER) [C(a−v)O₂/CaO₂] between the two altitudes [0.52 (0.48–0.71) at 4559 m and 0.53 (0.49–0.73) at 75 m, P=0.500]. Comparison of C(a−v)O₂ at peak V˙O2 at 4559 m and the equivalent V˙O2 at sea level for each participant also revealed no significant difference [83.9 (67.5–120.9) ml litre¹vs 81.2 (73.0–120.7) ml litre⁻¹, respectively, P=0.225].

Conclusion

In acclimatized individuals at 4559 m, there was a decline in maximum absolute C(a−v)O₂ during exercise but no alteration in OER calculated using central venous oxygen measurements. This suggests that oxygen extraction may have become limited after exposure to 7–8 days of hypoxaemia.

Four phases of intravenous fluid therapy: a conceptual model

I.V. fluid therapy plays a fundamental role in the management of hospitalized patients. While the correct use of i.v. fluids can be lifesaving, recent literature demonstrates that fluid therapy is not without risks. Indeed, the use of certain types and volumes of fluid can increase the risk of harm, and even death, in some patient groups. Data from a recent audit show us that the inappropriate use of fluids may occur in up to 20% of patients receiving fluid therapy. The delegates of the 12th Acute Dialysis Quality Initiative (ADQI) Conference sought to obtain consensus on the use of i.v. fluids with the aim of producing guidance for their use. In this article, we review a recently proposed model for fluid therapy in severe sepsis and propose a framework by which it could be adopted for use in most situations where fluid management is required. Considering the dose-effect relationship and side-effects of fluids, fluid therapy should be regarded similar to other drug therapy with specific indications and tailored recommendations for the type and dose of fluid. By emphasizing the necessity to individualize fluid therapy, we hope to reduce the risk to our patients and improve their outcome.

Indications and management of mechanical fluid removal in critical illness

BACKGROUND

The Acute Dialysis Quality Initiative (ADQI) dedicated its Twelfth Consensus Conference (2013) to all aspects of fluid therapy, including the management of fluid overload (FO). The aim of the working subgroup 'Mechanical fluid removal' was to review the indications, prescription, and management of mechanical fluid removal within the broad context of fluid management of critically ill patients.

METHODS

The working group developed a list of preliminary questions and objectives and performed a modified Delphi analysis of the existing literature. Relevant studies were identified through a literature search using the MEDLINE database and bibliographies of relevant research and review articles.

RESULTS

After review of the existing literature, the group agreed the following consensus statements: (i) in critically ill patients with FO and with failure of or inadequate response to pharmacological therapy, mechanical fluid removal should be considered as a therapy to optimize fluid balance. (ii) When using mechanical fluid removal or management, targets for rate of fluid removal and net fluid removal should be based upon the overall fluid balance of the patient and also physiological variables, individualized, and reassessed frequently. (iii) More research on the role and practice of mechanical fluid removal in critically ill patients not meeting fluid balance goals (including in children) is necessary.

CONCLUSION

Mechanical fluid removal should be considered as a therapy for FO, but more research is necessary to determine its exact role and clinical application.

Survival after postoperative morbidity: a longitudinal observational cohort study

Background

Previous studies have suggested that there may be long-term harm associated with postoperative complications. Uncertainty exists however, because of the need for risk adjustment and inconsistent definitions of postoperative morbidity.

Methods

We did a longitudinal observational cohort study of patients undergoing major surgery. Case-mix adjustment was applied and morbidity was recorded using a validated outcome measure. Cox proportional hazards modelling using time-dependent covariates was used to measure the independent relationship between prolonged postoperative morbidity and longer term survival.

Results

Data were analysed for 1362 patients. The median length of stay was 9 days and the median follow-up time was 6.5 yr. Independent of perioperative risk, postoperative neurological morbidity (prevalence 2.9%) was associated with a relative hazard for long-term mortality of 2.00 [P=0.001; 95% confidence interval (CI) 1.32–3.04]. Prolonged postoperative morbidity (prevalence 15.6%) conferred a relative hazard for death in the first 12 months after surgery of 3.51 (P<0.001; 95% CI 2.28–5.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.62–3.65), returning to baseline thereafter.

Conclusions

Prolonged morbidity after surgery is associated with a risk of premature death for a longer duration than perhaps is commonly thought; however, this risk falls with time. We suggest that prolonged postoperative morbidity measured in this way may be a valid indicator of the quality of surgical healthcare. Our findings reinforce the importance of research and quality improvement initiatives aimed at reducing the duration and severity of postoperative complications.

Perioperative increase in global blood flow to explicit defined goals and outcomes after surgery: a Cochrane Systematic Review

This systematic review and meta-analysis summarizes the clinical effects of increasing perioperative blood flow using fluids with or without inotropes/vasoactive drugs to explicit defined goals in adults. We included randomized controlled trials of adult patients (aged 16 years or older) undergoing surgery. We included 31 studies of 5292 participants. There was no difference in mortality at the longest follow-up: 282/2615 (10.8%) died in the control group and 238/2677 (8.9%) in the treatment group, RR of 0.89 (95% CI: 0.76-1.05; P=0.18). However, the results were sensitive to analytical methods and withdrawal of studies with methodological limitations. The intervention reduced the rate of three morbidities (renal failure, respiratory failure, and wound infections) but not the rates of arrhythmia, myocardial infarction, congestive cardiac failure, venous thrombosis, and other types of infections. The number of patients with complications was also reduced by the intervention. Hospital length of stay was reduced in the treatment group by 1.16 days. There was no difference in critical care length of stay. The primary analysis of this review showed no difference between groups but this result was sensitive to the method of analysis, withdrawal of studies with methodological limitations, and was dominated by a single large study. Patients receiving this intervention stayed in hospital 1 day less with fewer complications. It is unlikely that the intervention causes harm. The balance of current evidence does not support widespread implementation of this approach to reduce mortality but does suggest that complications and duration of hospital stay are reduced.

A novel ambulatory closed circuit breathing system for use during exercise

We describe a unique ambulatory closed circuit for delivering high fractions of inspired oxygen to an exercising user who does not require isolation from their environment. We describe the major components and their function and suggest potential applications for such a circuit. This circuit may benefit patients who are chronically dependant on oxygen, are unable to exercise due to hypoxia, or require oxygen supplementation at high altitude.

Pre-operative high sensitivity C-reactive protein and postoperative outcome in patients undergoing elective orthopaedic surgery

High-sensitivity C-reactive protein (hsCRP) adds important prognostic information, not reflected by traditional risk factors, to the prediction of both the development and outcome of cardiovascular pathology. HsCRP levels also correlate inversely with cardiorespiratory fitness, an important determinant of peri-operative outcome. We hypothesised that pre-operative hsCRP should be associated with excess peri-operative morbidity and longer length of stay. Pre-operative hsCRP was measured blinded to standardised postoperative outcomes in 129 elective orthopaedic patients. HsCRP levels were divided into high (> 3 mg x l(-1)) or low (< 3 mg x l(-1)) groups (Center for Disease Control stratification). High-CRP patients had significant cardiovascular history, received cardiac medication or steroid therapy (p < 0.05). Higher pre-operative hsCRP was associated with longer length of stay: mean 7.5 days (95% CI: 6.2-8.8) vs 6.0 days (95% CI: 5.5-6.5; p = 0.03; log rank test). In 21 patients with > 8 days length of stay, high pre-operative hsCRP patients were over-represented (p = 0.04). Pre-operative hsCRP is related to length of stay and delayed postoperative complications.

The Postoperative Morbidity Survey was validated and used to describe morbidity after major surgery

OBJECTIVES

To describe the reliability and validity of the Postoperative Morbidity Survey (POMS). To describe the level and pattern of short-term postoperative morbidity after major elective surgery using the POMS.

STUDY DESIGN AND SETTING

This was a prospective cohort study of 439 adults undergoing major elective surgery in a UK teaching hospital. The POMS, an 18-item survey that address nine domains of postoperative morbidity, was recorded on postoperative days 3, 5, 8, and 15.

RESULTS

Inter-rater reliability was perfect for 11/18 items (Kappa=1.0), with Kappa=0.94 for 6/18 items. A priori hypotheses that the POMS would discriminate between patients with known measures of morbidity risk, and predict length of stay were generally supported through observation of data trends, and there was statistically significant evidence of construct validity for all but the wound and neurological domains. POMS-defined morbidity was present in 325 of 433 patients (75.1%) remaining in hospital on postoperative day 3 after surgery, 231 of 407 patients (56.8%) on day 5, 138 of 299 patients (46.2%) on day 8, and 70 of 111 patients (63.1%) on day 15. Gastrointestinal (47.4%), infectious (46.5%), pain-related (40.3%), pulmonary (39.4%), and renal problems (33.3%) were the most common forms of morbidity.

CONCLUSION

The POMS is a reliable and valid survey of short-term postoperative morbidity in major elective surgery. Many patients remain in hospital without any morbidity as recorded by the POMS.

Doppler cardiac output monitoring: a tool for all physicians

This article introduces Doppler ultrasound cardiac output monitoring and outlines its increasing utility for managing patients with critical illness in the hospital environment.

Endotoxin immunity and the development of the systemic inflammatory response syndrome in critically ill children

BACKGROUND

The systemic inflammatory response syndrome (SIRS) may be triggered by endotoxin. Humans have antibodies directed against the core of endotoxin (endotoxin core antibodies, EndoCAb) that appear to be protective following surgery and in sepsis. We hypothesised that children with elevated antibodies to endotoxin core would be less likely to develop SIRS in their initial period on intensive care. Because of the existing literature we defined two sub-groups according to the primary reason for ICU admission: infection and non-infection.

METHODS

We recruited 139 consecutive patients admitted to a paediatric intensive care unit (PICU) with more than one organ failure for longer than 12 h as part of another study. Patients were classified on admission to PICU as having an infectious or a non-infections diagnosis. The occurrence of SIRS within 48 h of admission was recorded along with detailed clinical and demographic data, EndoCAb concentration and the potential confounding variables C-reactive protein and mannose-binding lectin.

RESULTS

In the 71 patients admitted without infection (primarily post-operative and head injured) IgG EndoCAb was significantly lower in patients who developed SIRS than those who did not (72 vs. 131 MU/ml), independent of potential confounding variables. In patients with infection there was no significant difference in IgG EndoCAb between children developing SIRS and those who did not (111 vs. 80 MU/ml).

CONCLUSION

Head injured and post-operative patients admitted to PICU who develop early SIRS have significantly lower serum IgG EndoCAb levels than those who do not.

Just scratching the surface

BACKGROUND AND OBJECTIVE

Different types of polymer surfaces affect the activation of platelets and coagulation pathway containers depending on their surface qualities. Importantly, this could produce variability of coagulation results obtained with thrombelastographical analysis. We assessed the effects of blood storage on thrombelastograph, TEG, variables using polypropylene and polycarbonate containers.

METHODS

An in vitro experiment was performed, with eight volunteers in each limb. Fresh whole blood was stored in polypropylene or polycarbonate tubes prior to TEGanalysis, to assess the role of these plastics in the TEG results obtained.

RESULTS

The polycarbonate tubes displayed slower onset of coagulation and greater variability of data for all four basic TEG variables (r-time, k-time, alpha-angle and maximum amplitude, P < 0.05). Polycarbonate results fell outside manufacturer reference ranges.

CONCLUSIONS

It is likely that this is due to the altered surface properties and charge effects of the containers affecting proteins and platelets differently. Caution should be used in choosing which containers are used for storage of fresh blood prior to coagulation assessment, as variable results will follow where different types of plastic containers are employed.

Comparison of P-POSSUM risk-adjusted mortality rates after surgery between patients in the USA and the UK

BACKGROUND

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) criteria have been used to assess surgical risk in patients in the UK. The aim was to determine how applicable these criteria are to patients undergoing surgery in the USA.

METHODS

Two cohorts of patients undergoing major non-cardiac surgery were followed prospectively in the USA (n = 1056) and the UK (n = 1539). Each patient was assigned a risk score for preoperative physiological status and operative severity using the established POSSUM criteria. Death in hospital was the primary outcome measure. For each patient a predicted risk of death was calculated from Portsmouth POSSUM (P-POSSUM) methodology using an established equation. The relationships between predicted and observed mortality rates in each cohort were investigated by means of multivariate logistic regression.

RESULTS

Within each cohort, an increase in risk estimated by P-POSSUM predicted an increase in observed mortality rate (P < 0.001). For any given risk level, however, mortality rates were significantly higher in the UK cohort than in the US cohort (odds ratio 4.50 (95 per cent confidence interval 2.81 to 7.19); Z = 6.25, P < 0.001).

CONCLUSION

An increase in predicted risk, based on the P-POSSUM methodology, was associated with a higher mortality rate in patients from both countries. However, risk-adjusted mortality rates following major surgery were four times higher in the UK cohort. These marked differences warrant validation in a larger number of centres.

A descriptive study of the variation in baseline levels of antiendotoxin core antibodies between US and UK populations

Low levels of naturally occurring antibodies to the core section of endotoxin (EndoCAb) have been shown to be predictors of poor outcome following major surgery. We performed a retrospective study comparing pre-operative levels in US surgical patients, UK surgical patients and healthy volunteers. Both IgM and IgG EndoCAb levels were higher in the US surgical patients when compared with the other groups (approximately twice as high in the case of IgG EndoCAb). This may reflect genetic or environmental variability between the patient groups, differences in the disease processes, the disparity in the delivery of health care between the two countries or degradation of the samples in transfer.

Assessment of preoperative fluid depletion using bioimpedance analysis

BACKGROUND

Fluid depletion during the perioperative period is associated with poorer outcome. Non-invasive measurement of total body water by bioimpedance may enable preoperative fluid depletion and its influence on perioperative outcome to be assessed.

METHODS

Weight and foot bioimpedance were recorded under standardized conditions in patients undergoing bowel preparation (n=43) or day surgery (n=44). Fifteen volunteers also followed standard nil-by-mouth instructions on two separate occasions to assess the variabilities of weight and bioimpedance over time.

RESULTS

Body weight fell by 1.27 kg (95% CI 1.03-1.50 kg; P<0.0001) and foot bioimpedance increased by 51 ohm after bowel preparation (95% CI 36-66; P<0.0001). Weight change after the nil-by-mouth period in day-surgery patients (mean -0.22 kg, 95% CI -0.05 to -0.47 kg; P=0.07) correlated (r=-0.46; P=0.005) with an increase in bioimpedance (16 ohms, 95% CI 5-27 ohms; P=0.01). No difference between two separate bioimpedance measurements was seen in the volunteer group.

CONCLUSIONS

Further work is warranted to determine if bioimpedance changes may serve as a useful indicator of perioperative fluid depletion.

Citrated blood does not reliably reflect fresh whole blood coagulability in trials of in vitro hemodilution

IMPLICATIONS

Citration and storage of whole blood markedly alter the Thrombelastograph effects of hemodilution on coagulation. The results of hemodilution studies in which citrated blood has been used to study coagulation may not be reliable.

Coagulation effects of in vitro serial haemodilution with a balanced electrolyte hetastarch solution compared with a saline-based hetastarch solution and lactated Ringer's solution

The hydroxyethyl starches are a group of compounds that has been associated with impairment of coagulation when large volumes are administered. The thrombelastograph is commonly used to assess point-of-care whole blood coagulation. Little is known about the dose-response relationships of haemodilution, and it is reasonable to assume that a linear association exists. This may not be the case with altered electrolyte compositions of the fluids used for haemodilution. We have therefore conducted an in vitro study of haemodilution of human whole blood using lactated Ringer's solution and two high molecular weight hetastarches, one in a balanced salt solution, the other in a 0.9% saline solution. The thrombelastograph, commonly used for the assessment of the coagulation effects of synthetic colloids, was used as the coagulation assessment device. Serial haemodilution with hetastarch in a balanced salt solution demonstrated a biphasic response (of r-times and k-times, as well as alpha angles), with haemodilution in the 20-40% range causing enhanced coagulation, and higher degrees of dilution causing a decrease in overall coagulation performance. A similar picture was observed with lactated Ringer's solution, but only significantly so in alpha angles. Hetastarch in saline did not display this initial increased coagulability at mild to moderate dilutions. This biphasic response of lactated Ringer's solution and hetastarch in a balanced salt solution reflects the complex interaction of fluids and the coagulation system, and that these effects cannot be attributed to simple haemodilution. On the other hand, there was a linear decrease in maximum amplitude with haemodilution. Maximum amplitude was particularly affected by both starches, which is an expected finding in view of the known interaction between the hydroxyethyl starches and von Willebrand's factor.

A prospective, randomized comparison of thromboelastographic coagulation profile in patients receiving lactated Ringer's solution, 6% hetastarch in a balanced-saline vehicle, or 6% hetastarch in saline during major surgery

OBJECTIVES

To compare the effects of lactated Ringer's solution (LR), 6% hetastarch in a balanced-saline vehicle (HS-BS), and 6% hetastarch in normal saline (HS-NS) on coagulation using thromboelastography.

DESIGN

Prospective, randomized double-blinded evaluation of previously published clinical trial.

SETTING

Tertiary-care medical center.

PARTICIPANTS

Patients undergoing elective noncardiac surgery with an anticipated blood loss >500 mL. A total of 90 patients were enrolled with 30 patients in each group.

INTERVENTIONS

Patients received a standardized anesthetic. LR, HS-BS, and HS-NS were administered intraoperatively based on a fluid administration algorithm. Hemodynamic targets included maintenance of arterial blood pressure, heart rate, and urine output within a predefined range.

MEASUREMENTS AND MAIN RESULTS

Thromboelastography variables for r time, k time, maximum amplitude, and alpha angle (mean +/- SD) were recorded at induction of anesthesia, at the end of surgery, and 24 hours postoperatively. Patients in the LR group showed a state of hypercoagulation at the end of surgery with reductions (p < 0.005) in r time (-3.8 +/- 6.7 mm) and k time (-1.7 +/- 2.5 mm). This state of hypercoagulation continued into the postoperative period. Patients in the HS-NS group showed a state of hypocoagulation with increases (p < 0.05) in r time (+6.2 +/- 8.5 mm) and k time (+1.7 +/- 3.9 mm) and a reduction in maximum amplitude (-8.0 +/- 9.8 mm) at the end of surgery. This state of hypocoagulation was reduced in the postoperative period. Patients in the HS-BS group showed no significant changes in coagulation status at end of surgery, with the smallest changes in r time (-0.3 +/- 4.1 mm), k time (+0.1 +/- 3.1 mm), maximum amplitude (-5.4 +/- 12.3 mm), and alpha angle (0.3 +/- 12.5 degrees ).

CONCLUSION

LR-treated patients exhibited a hypercoagulative profile that persisted into the postoperative period. HS-BS administration was associated with a lesser change in the coagulation profile compared with HS-NS, which was associated with a hypocoagulative state.

The effect of hypothermia on calculated values using saline and automated air tonometry

OBJECTIVE

To quantify in vitro the effect of hypothermia on results obtained when performing automated air tonometry (Tonocap, Datex-Ohmeda, Instrumentarium Corp, Helsinki, Finland) and saline tonometry.

DESIGN

In vitro validation study.

SETTING

University hospital research laboratory.

INTERVENTIONS

Two TRIP sigmoid catheters, one connected to the Tonocap device and the other instilled with 2.5 mL of 0.9% saline, were placed in a saline bath at 30.3 degrees C (mean) through which 5% carbon dioxide (CO(2)) was bubbled.

MEASUREMENTS AND MAIN RESULTS

A total of 50 paired measurements were taken at 30-minute equilibration times of saline bath CO(2) tension and saline tonometry and air tonometry readings. Saline samples were analyzed at 37 degrees C and corrected for temperature. Bias and precision of each technique as a percentage of predicted CO(2) values were calculated. The Tonocap device had bias and precision values of -2.6% and +/-1.4%. Measurement of CO(2) is in the gaseous phase so that temperature correction is not required. Saline tonometry readings processed at 37 degrees C exhibited a large positive bias of 23.06% (precision +/- 7.02%). Correction for temperature improved bias to -10.98 % with a similar precision profile of +/-5.78%.

CONCLUSION

When using gastrointestinal tonometry during hypothermic cardiopulmonary bypass, saline tonometry samples should be temperature corrected. The Tonocap device proved the most accurate and precise measurement technique independent of the need for temperature correction.

Preoperative and intraoperative predictors of postoperative morbidity, poor graft function, and early rejection in 190 patients undergoing liver transplantation

HYPOTHESIS

Preoperative and intraoperative variables predict in part adverse outcome after liver transplantation.

DESIGN

Prospective, blinded, cohort study.

SETTING

Tertiary care hospital.

SUBJECTS

A total of 190 adult patients undergoing primary liver transplantation.

MAIN OUTCOME MEASURE

Adverse outcome was prospectively defined as either in-hospital death or prolonged postoperative hospitalization (>14 days) associated with morbidity. Potential preoperative and intraoperative risk factors were collected. Associations were tested by univariate analysis followed by multivariate analysis in which preoperative factors were entered before intraoperative factors.

RESULTS

Adverse outcome occurred in 44.7% of patients. Incidences of other complications were as follows: in-hospital mortality (8.4%), primary graft nonfunction (4.2%), poor early graft function (1.1%), and early rejection (31.2%). Univariate predictors of adverse outcome were United Network for Organ Sharing status (P =.003), Child-Turcotte-Pugh score (P =.02), POSSUM physiological score (P =.002), recipient age (P =.01), preoperative serum high-density lipoprotein cholesterol level (P =.03), preoperative serum creatinine level (P =.002), preoperative serum total IgG level (P =.004), duration in hospital preoperatively (P =.03), operative duration (P<.001), allogeneic erythrocyte transfusions (P<.001), total intraoperative fluids (P =.002), and use of inotropic agents (P =.01). In the final multivariate model, predictors of adverse outcome were United Network for Organ Sharing status (P =.03), recipient age (P =.002), and total intraoperative fluids (P =.04). Most patients who died or had a prolonged hospitalization exhibited dysfunction of more than 1 organ system, including pulmonary, renal, and infectious complications.

CONCLUSIONS

Adverse outcome occurs frequently after liver transplantation, usually involves multiple organ systems, and is predicted in part by several preoperative and intraoperative factors.

The effects of balanced versus saline-based hetastarch and crystalloid solutions on acid-base and electrolyte status and gastric mucosal perfusion in elderly surgical patients

The IV administration of sodium chloride solutions may produce a metabolic acidosis and gastrointestinal dysfunction. We designed this trial to determine whether, in elderly surgical patients, crystalloid and colloid solutions with a more physiologically balanced electrolyte formulation, such as Hartmann's solution and Hextend, can provide a superior metabolic environment and improved indices of organ perfusion when compared with saline-based fluids. Forty-seven elderly patients undergoing major surgery were randomly allocated to one of two study groups. Patients in the Balanced Fluid group received an intraoperative fluid regimen that consisted of Hartmann's solution and 6% hetastarch in balanced electrolyte and glucose injection (Hextend). Patients in the Saline group were given 0.9% sodium chloride solution and 6% hetastarch in 0.9% sodium chloride solution (Hespan). Biochemical indices and acid-base balance were determined. Gastric tonometry was used as a reflection of splanchnic perfusion. Postoperative chloride levels demonstrated a larger increase in the Saline group than the Balanced Fluid group (9.8 vs 3.3 mmol/L, P = 0.0001). Postoperative standard base excess showed a larger decline in the Saline group than the Balanced Fluid group (-5.5 vs -0.9 mmol/L, P = 0.0001). Two-thirds of patients in the Saline group, but none in the Balanced Fluid group, developed postoperative hyperchloremic metabolic acidosis (P = 0.0001). Gastric tonometry indicated a larger increase in the CO2 gap during surgery in the Saline group compared with the Balanced Fluid group (1.7 vs 0.9 kPa, P = 0.0394). In this study, the use of balanced crystalloid and colloid solutions in elderly surgical patients prevented the development of hyperchloremic metabolic acidosis and resulted in improved gastric mucosal perfusion when compared with saline-based solutions.

IMPLICATIONS

This prospective, randomized, blinded trial showed that, in elderly surgical patients, the use of balanced IV solutions can prevent the development of hyperchloremic metabolic acidosis and provide better gastric mucosal perfusion compared with saline-based fluids.

Endotoxin-neutralizing capacity of serum from cardiac surgical patients

OBJECTIVE

To determine if endotoxin core antibody (EndoCAb) from the serum of cardiac surgical patients neutralizes endotoxin in an ex vivo biologic assay.

DESIGN

Prospective blinded cohort study.

SETTING

Academic medical center.

PARTICIPANTS

Patients (n = 203) undergoing cardiac surgery.

INTERVENTIONS

Sera were obtained from patients preoperatively.

MEASUREMENTS AND MAIN RESULTS

EndoCAb levels were determined by enzyme-linked immunosorbent assay. Sera were incubated for 15 minutes at 37 degrees C with varying concentrations of endotoxin from a clinically relevant bacterium (Escherichia coli serotype O18), then tested for the presence of endotoxin activity using the validated Limulus amebocyte lysate assay. Median (interquartile range) IgM and IgG EndoCAb levels were 118 median units (range, 31 to 259 median units) and 208 median units (range, 108 to 401 medium units). Increasing levels of IgM EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). Increasing levels of IgG EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). An additive effect of IgM and IgG EndoCAb levels on endotoxin neutralization was observed without evidence of synergistic or plateau effects. EndoCAb levels did not completely predict serum neutralization capacity.

CONCLUSION

Anti-EndoCAbs of both classes (IgM and IgG) were able to neutralize lipopolysaccharide from a clinically relevant bacterium in an ex vivo model. Neither Igm nor IgG appeared to be more capable of neutralization in this model. These antibodies did not completely predict neutralization capacity; other endogenous factors in human serum must be capable of lipopolysaccharide neutralization.

Decreased endotoxin immunity is associated with greater mortality and/or prolonged hospitalization after surgery

BACKGROUND

Patients undergoing noncardiac surgery often develop postoperative morbidity, potentially attributable to endotoxemia and the systemic inflammatory response syndrome. Endogenous antibodies to endotoxin may confer protection from endotoxin-mediated toxicity. The authors sought to determine the association of preoperative antiendotoxin immunity and death or prolonged hospitalization in a broad population of general surgical patients undergoing major surgery.

METHODS

To test the hypothesis that low preoperative serum antiendotoxin core antibody (EndoCAb) concentration is an independent predictor of adverse outcome after general surgery, 1,056 patients undergoing routine noncardiac surgery were enrolled into a prospective, blinded, cohort study. Immunoglobulin M EndoCAb, immunoglobulin G EndoCAb, total inmunoglobulin M, and immunoglobulin G concentrations were measured in serum obtained preoperatively. A physiologic risk score using the established POSSUM criteria was assigned preoperatively to each patient. The primary predefined composite end point (postoperative complication) was either in-hospital death or postoperative length of stay greater than 10 days. Multivariate logistic regression was used to test the study hypothesis.

RESULTS

Overall, postoperative complication occurred in 234 of the 1,056 patients (22.1%). Lower immunoglobulin M EndoCAb concentration (P = 0.006) predicted increased risk of postoperative complication independent of POSSUM physiologic risk score (P < 0.001). In contrast, total immunoglobulin M and total immunoglobulin G concentrations did not predict adverse outcome. Complications involved multiple organ systems and were generally unrelated to the type or site of surgery, consistent with the systemic inflammatory response syndrome.

CONCLUSIONS

Adverse outcome after routine noncardiac surgery is common and is predicted in part by low concentrations of EndoCAb. The authors' findings suggest that endotoxemia may be a cause of postoperative morbidity after routine noncardiac surgery.

Gastric tonometry: where do we stand?

Gastric tonometry has proved to be a sensitive but not specific predictor of outcome in the critically ill. The data accumulated to date indicate that those patients able to achieve or maintain a normal gastric mucosal pH do better than those who do not. In addition, therapy aimed at improving an abnormal gastric mucosal pH has proved to be less successful. These findings may simply indicate that tonometry identifies those "responders" and "nonresponders," as becomes increasingly apparent in populations of critical care patients receiving interventional therapy. Gastric tonometry has undergone a number of methodologic changes over the last decade, seeing a switch from saline to automated gas tonometry. Along with this switch of methodology has come a deeper scrutiny of the indices used to assess gut perfusion. Most studies (including all the interventional ones) have used gastric mucosal pH. The newer indices of gut luminal PCO2 (PgCO2) referenced to arterial CO2 (PgCO2-PaCO2) or end tidal CO2 (PgCO2-PeCO2), although relatively well validated, remain to be proven as predictors of outcome or guides to interventional therapy. If we take a fresh look at the interventional trials in intensive care patients, there is a very definite trend toward benefit in the protocol groups, although they are generally reported as negative studies. There is much to be accomplished, however, before we accept the gastric tonometer as a routine tool with which to guide therapy based on gastrointestinal perfusion, including a greater understanding of gastrointestinal physiology and, as ever, the call for an adequately powered prospective randomized controlled trial to evaluate the clinical utility of gas tonometry.

Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2

OBJECTIVE

To examine the speed of response of saline tonometry and an automated gas tonometry system by using standard tonometry catheters.

DESIGN

In vitro validation study.

SETTING

Experimental research laboratory.

INTERVENTIONS

Tonometry catheters were placed in a test chamber designed to simulate the lumen of a hollow viscus and were exposed to a rapid change in CO2 from 0% to 5% or 10%. Measured CO2 over time was fit to a mathematical model to determine the response time constant (the time to reach 63% of the final value) for each system.

MEASUREMENTS AND MAIN RESULTS

Response time to a change in CO2 was significantly faster with the automated gas system than with traditional saline tonometry. The mathematical time constant for a 5% change in CO2 in a gas environment was 2.8 mins (95% confidence interval, 2.6-3.0 mins) for the gas and 6.3 mins (95% confidence interval, 5.8-7.3 mins) for the saline technique. These times were longer for the CO2 change in a liquid environment: The time constant was 4.6 mins (95% confidence interval, 4.5-4.7 mins) for the gas system and 7.8 mins (95% confidence interval, 7.15-8.6 mins) for the saline tonometry. There was a significantly lower final equilibration value for the CO2 measurement with saline tonometry. There was essentially no difference in time constants for each system for a 5% change compared with a 10% CO2 change, except for a slightly faster time constant for the gas tonometry system with a 5% change in the gas environment (5%: 2.8 mins vs. 10%: 3.3 mins).

CONCLUSIONS

The automated gas tonometry system has a significantly faster response to a change in CO2 than conventional saline tonometry.

Preparation and preclinical evaluation of a novel liposomal complete-core lipopolysaccharide vaccine

Our objective is to develop a prophylactic vaccine strategy that can be evaluated for surgical and other high-risk hospitalized patients. In this paper, we describe the preparation and preclinical evaluation of a liposomal complete-core lipopolysaccharide (LPS) vaccine that is nontoxic and broadly antigenic. Complete-core (Ra-chemotype) LPSs were isolated from four gram-negative bacterial strains (Escherichia coli K-12, E. coli R1, Pseudomonas aeruginosa PAC608, and Bacteroides fragilis), mixed together to form a cocktail of complete-core LPSs, and then incorporated into multilamellar liposomes consisting of dimyristoyl phosphatidyl choline, dimyristoyl phosphatidylglycerol, and cholesterol in a 4:1:4 molar ratio. The endotoxic activities of these LPS-containing liposomes were less than 0.1% of the endotoxicities of the original free LPSs as measured by the Limulus amoebocyte lysate assay. In vivo administration of liposomal complete-core LPS mixed with Al(OH)(3) to rabbits resulted in no pyrogenicity or overt toxicity over a 7-day period. In immunoblots, sera from rabbits following active immunization elicited cross-reactive antibodies to a large panel of rough and smooth LPSs from numerous clinically relevant gram-negative bacteria, including E. coli (serotypes O1, O4, O6, O8, O12, O15, O18, O75, O86, O157, and O111), P. aeruginosa (Fisher-Devlin serotypes 1, 2, and 3, which correspond to International Antigenic Typing Scheme types 6, 11, and 2, respectively), Klebsiella pneumoniae (serotypes O1, O2ab, and O3), B. fragilis, and Bacteroides vulgatus. Active immunization of mice with liposomal complete-core LPS provided protection against a lethal challenge with E. coli O18 LPS. The vaccine tested was nontoxic, nonpyrogenic, and immunogenic against a wide variety of pathogens found in clinical settings.

Report from the meeting: Gastrointestinal Tonometry: State of the Art. 22nd-23rd May 1998, London, UK

Gastrointestinal (GI) tonometry, the only clinically available method for the accurate diagnosis of compromised GI blood flow, has been shown to be a sensitive predictor of increased morbidity, mortality and prolonged hospitalization. The recent introduction of the Tonocap, as a means of performing automated air tonometry, has simplified the application of GI tonometry in the clinical setting. Despite this the utility of GI tonometry remains controversial. The GI Tonometry: State of the Art meeting brought together a group of clinicians with a proven track record of research, clinical interest and expertise in this field. The aim of the meeting was to come to a consensus regarding certain issues such as the past and future roles of GI tonometry and standards for its correct usage and interpretation. Finally suggestions as to further research and clinical evaluation were made within a broader discussion regarding the complexities of applying the principles of evidence-based medicine to the introduction of a new piece of medical technology.

Automated detection of gastric luminal partial pressure of carbon dioxide during cardiovascular surgery using the Tonocap

BACKGROUND

A new automated system of air tonometry (Tonocap; Datex Ohmeda, Helsinki, Finland) allows for frequent (every 15 min) measurement of gastric luminal partial pressure of carbon dioxide. Its use has not been described in cardiac surgical patients.

METHODS

One hundred patients undergoing coronary artery bypass graft or cardiac valve surgery were enrolled in a prospective cohort study. After anesthetic induction and insertion of a TRIP NGS Catheter (Datex Ohmeda), measurements of gastric luminal partial pressure of carbon dioxide were obtained using the Tonocap, and gastric mucosal pH (pHi) was calculated. The main outcome measure was postoperative complication, defined as either in-hospital death or prolonged postoperative hospitalization (> 14 days).

RESULTS

Four patients (4%) died, all of multiple-system organ failure, one each on postoperative days 9, 26, 46, and 121. Postoperative complication occurred in 18 patients (18%), all of whom exhibited persistent dysfunction of at least one organ system. Perioperatively, an abnormal pHi (< 7.32) and gastric luminal minus arterial partial pressure of carbon dioxide gap (> 8 mmHg) occurred in 66% and 70% of patients, respectively. Predictors of postoperative complication included postoperative pHi (P = 0.001), gastric luminal partial pressure of carbon dioxide (P = 0.022), and gastric luminal minus arterial partial pressure of carbon dioxide gap (P = 0.013). In contrast, arterial base excess (P > 0.4) and routinely measured hemodynamic variables (e.g., heart rate, blood pressure) were either less predictive compared with Tonocap-derived variables or not predictive.

CONCLUSIONS

Despite a low mortality rate, patients undergoing cardiac surgery exhibited high incidences of prolonged hospitalization and postoperative morbidity. The Tonocap was easy to use, particularly compared with saline tonometry. Several Tonocap-derived variables were predictive of postoperative complications consistent with previously published data using saline tonometry.

The use of a postoperative morbidity survey to evaluate patients with prolonged hospitalization after routine, moderate-risk, elective surgery

Vital healthcare resources are devoted to caring for patients with prolonged hospitalization after routine, moderate-risk surgery. Despite the significant cost, little is known about the overall incidence and pattern of complications in these patients. Four hundred thirty-eight patients undergoing a diverse group of routine, moderate-risk, elective surgical procedures were enrolled into a prospective, blinded, cohort study. Complications were assessed using a postoperative morbidity survey. The main outcome was postoperative complication, defined as either in-hospital death or prolonged postoperative hospitalization (> 7 days). The mortality rate was 1.6%. Postoperative complications occurred in 118 patients (27% [95% CI 23-31]). Complications frequently observed in these patients included: gastrointestinal 51% (42-60), pulmonary 25% (17-33), renal 21% (14-28), and infectious 13% (7-19). Most complications were not directly related to the type/site of surgery. Indices of tissue trauma (blood loss [P < 0.001], surgical duration [P = 0.001]) and tissue perfusion (arterial base deficit [P = 0.008], gastric pHi [P = 0.02]) were the strongest intraoperative predictors of complications. Despite a low mortality rate, we found that complications after routine, moderate-risk, elective surgery are common and involve multiple organ systems. Our 9-point survey can be used by healthcare providers and payers to characterize post-operative morbidity in their respective settings.

IMPLICATIONS

Little is known about the overall incidence and pattern of complications in patients with prolonged hospitalization after routine, elective surgery. We prospectively assessed these complications using a novel postoperative morbidity survey. The postoperative morbidity survey can be used in future clinical outcome trials, as well as in routine hospital-based quality assurance.