Defining complexity in anaesthesia: description and validation of the Oxford Anaesthetic Complexity (OxAnCo) score.

Increasing demand for surgery and anaesthesia has created an imperative to manage anaesthetic workforce and caseload. This may include changes to distribution of cases amongst anaesthetists of different grades, including non-physician anaesthetists. To achieve this safely, an assessment of case complexity is essential. We present a novel system for scoring complexity of cases in anaesthesia, the Oxford Anaesthetic Complexity score. This integrates patient, anaesthetic, surgical and systems factors, and is different from assessments of risk. We adopted an end-user development approach to the design of the score, and validated it using a dataset of anaesthetic cases. Across 688 cases, the median (IQR [range]) complexity score was 19 (17-22 [15-33]). Cases requiring a consultant anaesthetist had a significantly higher median (IQR [range]) score than those requiring a senior trainee at 22 (20-25 [15-33]) vs. 19(17-21 [15-28]), p < 0.001. Cases undertaken in a tertiary acute hospital had a significantly higher score than those in a district general hospital, the median (IQR [range]) scores being 20 (17-22 [15-33]) vs. 17 (16-19 [17-28]), p < 0.001. Receiver-operating characteristic analysis showed good prediction of complexity sufficient to require a consultant anaesthetist, with area under the curve of 0.84. Any rise in complexity above baseline (score > 15) was strongly predictive of a case too complex for a junior trainee (positive predictive value 0.93). The Oxford Anaesthetic Complexity score can be used to match cases to different grades of anaesthetist, and can help in defining cases appropriate for the expanding non-physician anaesthetist workforce.

Identification and mapping of the promoter for the gene encoding the ferritin heavy-chain homologue of the yellow fever mosquito Aedes aegypti.

Mosquitoes are responsible for the transmission of numerous human diseases. The recent development of transgenic mosquitoes provides a new tool to examine molecular interactions between insect vectors and the pathogens they transmit. One focus in generating transgenic mosquito lies on expressing anti-pathogenic proteins at primary sites of pathogenic invasions, specifically the mosquito gut. Promoters that direct the expression of anti-pathogenic proteins in the mosquito gut are thus sought after because they may provide ways to hinder pathogenic development in the mosquito. Here, we report the identification and mapping of a strong promoter from the Aedes aegypti ferritin heavy-chain homologue (HCH) gene. All known insect ferritin HCH genes are expressed in the gut and inducible by an iron overload. Our transfection assays and DNase I footprinting analyses show that the mosquito ferritin HCH-gene contains regulatory elements both upstream and downstream of the transcriptional start site. The promoter of this gene contains a CF2 site, two GATA-binding sites, an E2F site, a TATA-box, an AP-1 site and a C/EBP binding site.

DRG payment for long-term ventilator patients--revisited.

This article provides a follow-up to an evaluation originally presented in Chest of the financial impact of diagnosis related group (DRG) payment for long-term ventilator-dependent Medicare patients at Rush-Presbyterian-St. Luke's Medical Center. Since the results of our original study were presented, the Health Care Financing Administration (HCFA) has created two new DRGs for patients who have respiratory principal diagnoses to help recognize the resource intensiveness associated with mechanical ventilator support. The original 95 patients' payment, which was originally calculated to be $2.2 million below costs, was recalculated to be $1.9 million below costs, representing a 13 percent reduction in the loss. We conclude that although HCFA's recent remedial action is a step in the right direction, it provides little relief from the DRG system's financial bias against long-term ventilator-dependent patients, because the new ventilator DRGs encompass only a small segment of these patients. As an alternative approach, we recommend a single DRG for patients who, regardless of their principal diagnoses, experience chronic respiratory failure requiring a minimum of three days of continuous ventilator treatment.

Long-term outcomes for elderly survivors of prolonged ventilator assistance.

Care of ventilator-dependent patients requires considerable resources, yet the long-term outcomes of this type of care have rarely been described. We retrospectively investigated the posthospital course of elderly patients who survived an episode of prolonged ventilator dependency to describe survival rates, subsequent use of health care resources, and functional abilities. Our data suggest that the use of prolonged mechanical ventilation in the elderly produces few survivors at considerable expense. Poor overall outcomes occurred despite considerable consumption of medical and nursing resources by the survivors.

DRG payment for long-term ventilator patients. Implications and recommendations.

Much concern has been expressed about the Medicare Prospective Payment System's impact on access to care. In this study, we examine the financial impact of diagnosis-related group (DRG) payment for chronic ventilator-dependent Medicare patients. During a one-year period, payment for 95 Medicare patients who received a minimum of three days of continuous ventilator treatment and who spent no time in surgical intensive care at Rush-Presbyterian-St. Luke's Medical Center, was calculated to be $2.2 million below costs, representing an average loss per discharge of $23,129. Patients stayed an average of 26.6 days, of which 14.2 days were spent on a ventilator. We conclude that the results suggest a financial bias against chronic ventilator-dependent patients exists in the DRG system which could present access problems. We recommend three approaches to recognizing the cost of care for such patients in the DRG payment system and encourage those in public policy-making positions to use our results as the basis for a larger scale analysis of the impact of Medicare DRG payment on chronic ventilator-dependent patients.

The hazard of spatial disorientation during helicopter flight using night vision devices.

INTRODUCTION: Night Vision Devices (NVDs) provide an enormous advantage to the operational effectiveness of military helicopter flying by permitting flight throughout the night. However, compared with daytime flight, many of the depth perception and orientational cues are severely degraded. These degraded cues predispose aviators to spatial disorientation (SD), which is a serious drawback of these devices. METHODS: As part of an overall analysis of Army helicopter accidents to assess the impact of SD on military flying, we scrutinized the class A-C mishap reports involving night-aided flight from 1987 to 1995. The accidents were classified according to the role of SD by three independent assessors, with the SD group further analyzed to determine associated factors and possible countermeasures. RESULTS: Almost 43% of all SD-related accidents in this series occurred during flight using NVDs, whereas only 13% of non-SD accidents involved NVDs. An examination of the SD accident rates per 100,000 flying hours revealed a significant difference between the rate for day flying and the rate for flight using NVDs (mean rate for daytime flight = 1.66, mean rate for NVD flight = 9.00, p < 0.001). The most important factors associated with these accidents were related to equipment limitations, distraction from the task, and training or procedural inadequacies. CONCLUSIONS: SD remains an important source of attrition of Army aircraft. The more than fivefold increase in risk associated with NVD flight is of serious concern. The associated factors and suggested countermeasures should be urgently addressed.

Regulation of the ferritin heavy-chain homologue gene in the yellow fever mosquito, Aedes aegypti.

In the yellow fever mosquito Aedes aegypti, the ferritin heavy-chain homologue (HCH) gene is induced by blood feeding. This suggests that ferritin may serve as a cytotoxic protector against the oxidative challenge of the blood meal and may be essential for the survival of the insect. In this study, various cis-acting elements for the gene were identified and mapped. Transfection assays showed that the strength and activity of a subset of these elements are orientation-dependent. The shift observed for the ferritin HCH cis-acting elements is unique among known ferritin genes. DNase I footprinting data together with Transfac analyses identified a number of putative sites known for their involvement in developmental and cell proliferation processes.

The pneumoplex assays, a multiplex PCR-enzyme hybridization assay that allows simultaneous detection of five organisms, Mycoplasma pneumoniae, Chlamydia (Chlamydophila) pneumoniae, Legionella pneumophila, Legionella micdadei, and Bordetella pertussis, and its real-time counterpart.

Respiratory disease caused by atypical bacteria remains an important cause of morbidity and mortality for adults and children, despite the widespread use of effective antimicrobials agents. Culture remains the "gold standard" for the detection of these agents. However, culture is labor-intensive, takes several days to weeks for growth, and can be very insensitive for the detection of some of these organisms. Newer singleplex PCR diagnostic tests are sensitive and specific, but multiple assays would be needed to detect all of the common pathogens. Therefore, we developed the Pneumoplex assays, a multiplex PCR-enzyme hybridization assay (the standard assay) and a multiplex real-time assay to detect the most common atypical pathogens in a single test. Primer and probe sequences were designed from conserved regions of specific genes for each of these organisms. The limits of detection were as follows: for Bordetella pertussis, 2 CFU/ml; for Legionella pneumophila (serotypes 1 to 15) and Legionella micdadei, 9 and 80 CFU/ml, respectively; for Mycoplasma pneumoniae, 5 CFU/ml; and for Chlamydia (Chlamydophila) pneumoniae, 0.01 50% tissue culture infective doses. Recombinant DNA controls for each of these organisms were constructed, and the number of copies for each DNA control was calculated. The Pneumoplex could detect each DNA control down to 10 copies/ml. The analytical specificity demonstrated no cross-reactivity between 23 common respiratory pathogens. One hundred twenty-five clinical bronchoalveolar lavage fluid samples tested by the standard assay demonstrated that the Pneumoplex yielded a sensitivity and a specificity of 100 and 98.5%, respectively. This test has the potential to assist clinicians in establishing a specific etiologic diagnosis before initiating therapy, to decrease hospital costs, and to prevent inappropriate antimicrobial therapy.