Cohort analysis of outcomes in 69†490 emergency general surgical admissions across an international benchmarking collaborative.

OBJECTIVE: This study aims to use the Dr Foster Global Comparators Network (GC) database to examine differences in outcomes following high-risk emergency general surgery (EGS) admissions in participating centres across 3 countries and to determine whether hospital infrastructure factors can be linked to the delivery of high-quality care. DESIGN: A retrospective cohort analysis of high-risk EGS admissions using GC's international administrative data set. SETTING: 23 large hospitals in Australia, England and the USA. METHODS: Discharge data for a cohort of high-risk EGS patients were collated. Multilevel hierarchical logistic regression analysis was performed to examine geographical and structural differences between GC hospitals. RESULTS: 69 490 patients, admitted to 23 centres across Australia, England and the USA from 2007 to 2012, were identified. For all patients within this cohort, outcomes defined as: 7-day and 30-day inhospital mortality, readmission and length of stay appeared to be superior in US centres. A subgroup of 19 082 patients (27%) underwent emergency abdominal surgery. No geographical differences in mortality were seen at 7 days in this subgroup. 30-day mortality (OR=1.47, p<0.01) readmission (OR=1.42, p<0.01) and length of stay (OR=1.98, p<0.01) were worse in English units. Patient factors (age, pathology, comorbidity) were significantly associated with worse outcome as were structural factors, including low intensive care unit bed ratios, high volume and interhospital transfers. Having dedicated EGS teams cleared of elective commitments with formalised handovers was associated with shorter length of stay. CONCLUSIONS: Key factors that influence outcomes were identified. For patients who underwent surgery, outcomes were similar at 7 days but not at 30 days. This may be attributable to better infrastructure and resource allocation towards EGS in the US and Australian centres.

Infant repair of massive aortic aneurysm with prosthetic valved conduit.

A 4-month-old child with severe infantile Marfan syndrome underwent successful repair of an extremely dilated aortic root and severe aortic valve insufficiency using a prosthetic valved conduit.

Successful trans-Atlantic air ambulance transfer of a patient supported by a bi-ventricular assist device.

The ventricular assist device (VAD) is a hemodynamic support device that augments cardiac output for patients with severe ventricular dysfunction. With improved reliability and technological advances, the use of VADs to support patients is increasing. Many VAD-dependent patients ultimately require heart transplants that are only available in specialized centers, necessitating an interhospital transfer. To date there are few reports of long-distance fixed wing aeromedical transport of patients dependent on a VAD. Here we describe the successful transfer of a patient supported by a biventricular assist device (BiVAD) from Cambridge, UK, to Durham, NC, via fixed-wing jet aircraft. During this transfer, we observed hemodynamic alterations secondary to gravitational forces, which should be anticipated and may be mitigated with simple maneuvers. With high-level logistical planning and appropriate medical oversight, patients dependant on BiVADs can be safely transported by fixed wing aircraft over long distances.

Microbubble production in an in vitro cardiopulmonary bypass circuit ventilated with xenon.

Xenon, as an anaesthetic gas, has the potential to be used in an increasing range of applications. However, its use in cardiopulmonary bypass (CPB) has not yet progressed from the rat model due to concerns that its relative insolubility may cause microbubble formation and/or expansion in the micro-vasculature of the patient. An in vitro CPB circuit was designed to create and measure gaseous microbubbles over a range of temperature gradients, pressure drop and gas tensions. We were able to demonstrate that our test circuit did not produce any significant microbubbles and that, under normal physiological blood pressures, a fixed gas bubble in connection with the circuit did not grow in the presence of Xe.

Prolonged function of extracorporeal hDAF transgenic pig livers perfused with human blood.

BACKGROUND: The development of genetically modified pigs has renewed interest in the use of porcine liver perfusion in the treatment of acute liver failure. METHOD: A previously developed model of extracorporeal perfusion has been used to test the function of porcine livers transgenic for human decay accelerating factor when perfused with fresh, whole, human blood. Three experimental groups were studied: alloperfusions (normal pig livers perfused with pig blood) and xenoperfusions of both unmodified and transgenic pig livers with human blood. All livers were perfused for up to 72 hr. RESULTS: Alloperfusion resulted in the maintenance of good function and histological structure. Stable hemodynamic, synthetic, and metabolic parameters were demonstrated in both unmodified and transgenic liver xenoperfusions; hyperacute rejection was not seen. In both groups, however, the measured parameters of liver function deteriorated toward the end of the 72 hr perfusion period; deterioration was more marked in the nontransgenic group. Xenoperfusions were characterized by a progressive and marked decrease in hematocrit of the circulating blood. Histologically, patchy necrosis was noted in both groups and more retained erythrocytes were seen in the sinusoids of nontransgenic livers, but no other consistent differences were apparent. CONCLUSIONS: These studies have demonstrated that porcine liver xenoperfusions can be performed for prolonged periods while maintaining good liver function. The use of organs from animals transgenic for a human complement regulator protein confers improvement in some measures of liver function. This preclinical model provides evidence that extracorporeal liver xenoperfusion may be effective in temporary liver support for patients in acute liver failure.

Successful extracorporeal porcine liver perfusion for 72 hr.

BACKGROUND: Improvements in extracorporeal perfusion technology and the production of transgenic pigs resistant to hyperacute rejection have stimulated several groups to re-explore the possibility of supporting patients in hepatic failure with extracorporeal porcine livers. The success of organ transplantation has also stimulated interest in using extracorporeal perfusion as a means of organ preservation and resuscitation of organs from marginal donors. The present study describes a method by which livers can be maintained in a viable condition for a minimum of 72 hr of normothermic, extracorporeal perfusion. METHODS: Five extracorporeal porcine liver perfusions were performed, each with a duration of 72 hr. Hepatectomy was performed, followed by cold preservation, cannulation of vessels, and initiation of perfusion with normothermic, oxygenated porcine blood. Organ viability was assessed by metabolic, synthetic, hemodynamic, and histologic parameters. RESULTS: After 72 hr of normothermic, extracorporeal perfusion, the isolated livers demonstrated maintenance of normal physiological levels of pH and electrolytes. Continued hepatic protein synthesis (complement and factor V) was maintained throughout the perfusion. Hemodynamic parameters remained within normal physiological range. Histology demonstrated good preservation of the liver with no overall architectural change. CONCLUSION: It is possible to maintain a liver in a viable condition for a minimum of 72 hr of extracorporeal perfusion. This technique has been developed primarily as a preclinical model of extracorporeal liver support with the intention of proceeding to a clinical trial in patients with fulminant liver failure. However, it also has potential applications in organ preservation or resuscitation before transplantation and in the experimental study of isolated liver physiology.