Validation of personal protective equipment ensembles, incorporating powered air-purifying respirators protected from contamination, for the care of patients with high-consequence infectious diseases.

BACKGROUND: The UK High-Consequence Infectious Diseases (HCID) Network of high-level isolation units provides care for patients with contact- or airborne-transmissible highly infectious and highly dangerous diseases. In most HCID units, the healthcare workers (HCWs) wear personal protective equipment (PPE) ensembles incorporating a powered air-purifying respirator (PAPR) for head and respiratory protection. Some PAPRs have components worn outside/over other PPE, necessitating decontamination of re-usable elements. Two alternative PAPRs, with all re-usable elements worn under PPE, were trialled in this study. AIM: To undertake scenario-based testing of PAPRs and PPE to determine usability, comfort and ability to remove contaminated PPE without personal cross-contamination. METHODS: Trained healthcare volunteers (N=20) wearing PAPR/PPE ensembles were sprayed with ultraviolet fluorescent markers. They undertook exercises to mimic patient care, and subsequently, after doffing the contaminated PPE following an established protocol, any personal cross-contamination was visualized under ultraviolet light. Participants also completed a questionnaire to gauge how comfortable they found the PPE. FINDINGS AND CONCLUSIONS: The ensembles were tested under extreme 'worst case scenario' conditions, augmented by physical and manual dexterity tests. Participating volunteers considered the exercise to be beneficial in terms of training and PPE evaluation. Data obtained, including feedback from questionnaires and doffing buddy observations, supported evidence-based decisions on the PAPR/PPE ensemble to be adopted by the HCID Network. One cross-contamination event was recorded in the ensemble chosen; this could be attributed to doffing error, and could therefore be eliminated with further practice.

Universal use of surgical masks is tolerated and prevents respiratory viral infection in stem cell transplant recipients.

Prevention of respiratory viral infection in stem cell transplant patients is important due to its high risk of adverse outcome. This single-centre, mixed methods study, conducted before the severe acute respiratory syndrome coronavirus-2 pandemic, explored the barriers and facilitators to a policy of universal mask use by visitors and healthcare workers, and examined the impact of the first year of introduction of the policy on respiratory viral infection rates compared with preceding years, adjusted for overall incidence. Education around universal mask use was highlighted as being particularly important in policy implementation. A significant decrease in respiratory viral infection was observed following introduction.

'VIOLET': a fluorescence-based simulation exercise for training healthcare workers in the use of personal protective equipment.

BACKGROUND: Healthcare workers caring for patients with high-consequence infectious diseases (HCIDs) require protection from pathogen exposure, for example by wearing personal protective equipment (PPE). Protection is acquired through the inherent safety of the PPE components, but also their safe and correct use, supported by adequate training and user familiarity. However, the evidence base for HCID PPE ensembles and any associated training is lacking, with subsequent variation between healthcare providers. AIM: To develop an evidence-based assessment and training tool for evaluating PPE ensembles and doffing protocols, in the assessment of patients with suspected HCIDs. METHODS: VIOLET (Visualising Infection with Optimised Light for Education and Training) comprises a healthcare mannequin adapted to deliver simulated bodily fluids containing UV-fluorescent tracers. On demand and remotely operated, the mannequin projectile vomits (blue), coughs (red), has diarrhoea (yellow) and is covered in sweat (orange). Wearing PPE, healthcare staff participate in an HCID risk assessment and examination of the 'patient', thereby becoming exposed to these bodily fluids. Contamination of PPE is visualized and body-mapped under UV light before and after removal. Observational findings and participant feedback, around its use as a training exercise, is also recorded. FINDINGS: Significant contamination from different exposure events was seen, enabling evaluation of PPE and doffing procedures used. Observational data and participant feedback demonstrated its strengths and success as a training technique. CONCLUSION: Simulation exercises using VIOLET provide evidence-based assessment of PPE ensembles, and are a valuable resource for training of healthcare staff in wearing and safe doffing of PPE.

Use of ultraviolet-fluorescence-based simulation in evaluation of personal protective equipment worn for first assessment and care of a patient with suspected high-consequence infectious disease.

BACKGROUND: Variations currently exist across the UK in the choice of personal protective equipment (PPE) used by healthcare workers when caring for patients with suspected high-consequence infectious diseases (HCIDs). AIM: To test the protection afforded to healthcare workers by current PPE ensembles during assessment of a suspected HCID case, and to provide an evidence base to justify proposal of a unified PPE ensemble for healthcare workers across the UK. METHODS: One 'basic level' (enhanced precautions) PPE ensemble and five 'suspected case' PPE ensembles were evaluated in volunteer trials using 'Violet'; an ultraviolet-fluorescence-based simulation exercise to visualize exposure/contamination events. Contamination was photographed and mapped. FINDINGS: There were 147 post-simulation and 31 post-doffing contamination events, from a maximum of 980, when evaluating the basic level of PPE. Therefore, this PPE ensemble did not afford adequate protection, primarily due to direct contamination of exposed areas of the skin. For the five suspected case ensembles, 1584 post-simulation contamination events were recorded, from a maximum of 5110. Twelve post-doffing contamination events were also observed (face, two events; neck, one event; forearm, one event; lower legs, eight events). CONCLUSION: All suspected case PPE ensembles either had post-doffing contamination events or other significant disadvantages to their use. This identified the need to design a unified PPE ensemble and doffing procedure, incorporating the most protective PPE considered for each body area. This work has been presented to, and reviewed by, key stakeholders to decide on a proposed unified ensemble, subject to further evaluation.

Orally administered glucagon-like peptide-1 affects glucose homeostasis following an oral glucose tolerance test in healthy male subjects.

Glucagon-like peptide-1 (GLP-1) exerts several effects on glucose homeostasis and reduces food intake. After its release from intestinal L cells, GLP-1 is subject to (i) rapid breakdown by dipeptidyl peptidase IV and (ii) high liver extraction. The highest concentrations of GLP-1 are found in the splanchnic blood rather than in the systemic circulation. An oral delivery system would mimic endogenous secretion. Here we investigated the pharmacokinetic/pharmacodynamic (PK/PD) effects of a single dose (2 mg) of oral GLP-1 administered prior to an oral glucose tolerance test (OGTT) in 16 healthy males. GLP-1 was rapidly absorbed from the gut, leading to tenfold higher plasma concentrations compared with controls. The PD profile was consistent with reported pharmacology; GLP-1 significantly stimulated basal insulin release (P < 0.027), with marked effects on glucose levels. The postprandial glucose peak was delayed with GLP-1, suggesting an effect on gastric emptying.

Pharmacokinetics and pharmacodynamic effects of oral GLP-1 and PYY3-36: a proof-of-concept study in healthy subjects.

This proof-of-concept study was performed in order to establish the pharmacokinetics and pharmacodynamics of increasing oral doses of the satiety peptides glucagon-like peptide-1 (GLP-1) and peptide YY3-36 (PYY3-36). Six healthy male subjects were given oral doses of either a placebo or GLP-1 in a dose-escalating schedule (doses of 0.5, 1.0, 2.0, and 4.0 mg). Next, another group of six healthy male subjects were given oral doses of either a placebo or PYY3-36 in the same pattern of escalating doses (doses of 0.25, 0.5, 1.0, 2.0, and 4.0 mg). In healthy male volunteers, (i) oral administration of either of the peptides induced a rapid and dose-dependent increase in plasma drug concentrations; (ii) oral administration of GLP-1 induced a potent effect on insulin release; and (iii) both peptides suppressed ghrelin secretion. In conclusion, this study showed, for the first time, that satiety peptides such as GLP-1 and PYY3-36 can be orally delivered safely and effectively in humans.