Non-Contact Assessment of Peripheral Artery Haemodynamics Using Infrared Video Thermography.

Skin temperature has long been used as a natural indicator of vascular diseases in the extremities. Considerable correlation between oscillations in skin surface temperature and oscillations of skin blood flow has previously been demonstrated. We hypothesised that the impairment of blood flow in stenotic (subcutaneous) peripheral arteries would influence cutaneous temperature such that, by measuring gradients in the temperature distribution over skin surfaces, one may be able to diagnose or quantify the progression of vascular conditions in whose pathogenesis a reduction in subcutaneous blood perfusion plays a critical role (e.g. peripheral artery disease). As proof of principle, this study investigates the local changes in the skin temperature of healthy humans (15 male, [Formula: see text] years old, BMI [Formula: see text] kg/m 2) undergoing two physical challenges designed to vary their haemodynamic status. Skin temperature was measured in four central regions (forehead, neck, chest, and left shoulder) and four peripheral regions (left upper arm, forearm, wrist, and hand) using an infrared thermal camera. We compare inter-region patterns. Median temperature over the peripheral regions decreased from baseline after both challenges (maximum decrease: [Formula: see text] °C at 60 s after exercise; [Formula: see text] and [Formula: see text] °C at 180 s of cold-water immersion; [Formula: see text]). Median temperature over the central regions showed no significant changes. Our results show that the non-contact measurement of perfusion-related changes in peripheral temperature from infrared video data is feasible. Further research will be directed towards the thermographic study of patients with symptomatic peripheral vascular disease.

DALES, Drug Allergy Labels in Elective Surgical patients: a prospective multicentre cross-sectional study of incidence, risks, and attitudes in penicillin de-labelling strategies.

BACKGROUND: Penicillin allergy is associated with a range of poor health outcomes. Allergy testing can be made simpler by using a direct drug provocation test in patients at low risk of genuine allergy. This approach could allow population-level 'de-labelling'. We sought to determine the incidence and nature of penicillin allergy labels in UK surgical patients and define patient and anaesthetist attitudes towards penicillin allergy testing. METHODS: A prospective cross-sectional questionnaire study was performed in 213 UK hospitals. 'Penicillin allergic' patients were interviewed and risk-stratified. Knowledge and attitudes around penicillin allergy were defined in patients and anaesthetists. RESULTS: Of 21 219 patients, 12% (n=2626) self-reported penicillin allergy; 27% reported low-risk histories potentially suitable for a direct drug provocation test; an additional 40% reported symptoms potentially suitable for a direct drug provocation test after more detailed assessment. Of 4798 anaesthetists, 40% claimed to administer penicillin routinely when they judged the label low risk. Only 47% of anaesthetists would be happy to administer penicillin to a patient previously de-labelled by an allergy specialist using a direct drug provocation test; perceived lack of support was the most common reason for not doing so. CONCLUSIONS: At least 27% of patients with a penicillin allergy label may be suitable for a direct drug provocation test. Anaesthetists demonstrated potentially unsafe prescribing in patients with penicillin allergy labels. More than half of anaesthetists lack confidence in the results of a direct drug provocation tests undertaken by a specialist. Our findings highlight significant barriers to the effective implementation of widespread de-labelling in surgical patients.

Non-invasive stroke volume estimation by transthoracic electrical bioimpedance versus Doppler echocardiography in healthy volunteers.

Thoracic electrical bioimpedance (TEB) and transthoracic echocardiography (TTE) are non-invasive methods to estimate stroke volume (SV) and cardiac output (CO). Thoracic electrical bioimpedance is not in widespread clinical use with reports of inaccurate cardiac output estimation compared to invasive monitors, particularly in non-healthy populations. We explore its use as a trend monitor by comparing it against thoracic echocardiography in fifteen healthy volunteers undergoing two physical challenges designed to vary cardiac output. Of all paired values, 54.6% showed gross trend agreement and only 1.9% showed direct disagreement between the two monitors. Our results show thoracic bioimpedance may have a role as a non-invasive cardiac output trend monitor in healthy volunteer studies.