Paul M. Middleton

Agreement between arterial and central venous values for pH, bicarbonate, base excess, and lactate

Objective: This study aimed to determine the extent of agreement between central venous and arterial values for pH, bicarbonate, base excess, and lactate in a group of intensive care unit (ICU) patients. Methods: A prospective study of a convenience sample of patients deemed by their treating doctor to require blood gas analysis as part of their clinical care in ICU. It compared pH, bicarbonate, base excess and lactate on arterial and central venous samples taken within five minutes of each other. Data were analysed using bias (Bland–Altman) methods. Results: A total of 168 matched sample pairs from 110 patients were entered into the study. All variables showed close agreement. The mean difference between arterial and venous values of pH was 0.03 pH units, for bicarbonate 0.52 mmol/l, for lactate 0.08 mmol/l, and for base excess 0.19 mmol/l. All showed acceptably narrow 95% limits of agreement. Conclusion: Central venous pH, bicarbonate, base excess, and lactate values showed a high level of agreement with the respective arterial values, with narrow 95% limits of agreement. These results suggest that venous values may be an acceptable substitute for arterial measurement in this clinical setting.

A systematic review of the costs and benefits of helicopter emergency medical services

INTRODUCTION Helicopter emergency medical services (HEMS) are popular in first world health systems despite inconsistent evidence in the scientific literature to support their use. The aim of the current study was to perform a systematic review of economic evaluations of HEMS, in order to determine the economic cost of HEMS and the associated patient-centered benefits. METHOD A systematic review was performed of studies that provided a cost estimate of HEMS. The inclusion criteria consisted of English language articles that estimated both the costs and outcomes of a HEMS and fulfilled pre-specified criteria in relation to a cost analysis, cost-minimisation, cost-effectiveness or cost-benefit evaluation. Identified studies were synthesised according to the patient diagnosis (trauma, non-trauma or non-specific) and the type of HEMS transport under review (primary scene retrieval or secondary inter-facility transport). All costs were converted to US dollars and indexed for inflation. RESULTS Fifteen studies met the inclusion criteria. Among all studies the annual cost of HEMS ranged from

Pan‐Asian Resuscitation Outcomes Study (PAROS): Rationale, Methodology, and Implementation

115,777 to

Effectiveness of Morphine, Fentanyl, and Methoxyflurane in the Prehospital Setting

5,571,578. Five studies showed HEMS to be a more expensive transport alternative without an associated benefit while eight studies provided cost-effectiveness ratios of

Effectiveness of prehospital morphine, fentanyl, and methoxyflurane in pediatric patients.

3292 and

Spectral analysis of finger photoplethysmographic waveform variability in a model of mild to moderate haemorrhage.

2227 per life year saved for trauma,

Non-invasive classification of severe sepsis and systemic inflammatory response syndrome using a nonlinear support vector machine: a preliminary study

3258 per life saved and

Automatic detection of left ventricular ejection time from a finger photoplethysmographic pulse oximetry waveform: comparison with Doppler aortic measurement

7138 and

Practical use of the Glasgow Coma Scale; a comprehensive narrative review of GCS methodology

12,022 per quality adjusted life year for non-trauma and

Frequency spectrum analysis of finger photoplethysmographic waveform variability during haemodialysis.

30,365 and