Face Coverings, Aerosol Dispersion and Mitigation of Virus Transmission Risk.

The SARS-CoV-2 virus is primarily transmitted through virus-laden fluid particles ejected from the mouth of infected people. Face covers can mitigate the risk of virus transmission but their outward effectiveness is not fully ascertained. Objective: by using a background oriented schlieren technique, we aim to investigate the air flow ejected by a person while quietly and heavily breathing, while coughing, and with different face covers. Results: we found that all face covers without an outlet valve reduce the front flow through by at least 63% and perhaps as high as 86% if the unfiltered cough jet distance was resolved to the anticipated maximum distance of 2-3 m. However, surgical and handmade masks, and face shields, generate significant leakage jets that may present major hazards. Conclusions: the effectiveness of the masks should mostly be considered based on the generation of secondary jets rather than on the ability to mitigate the front throughflow.

Survival from profound metabolic acidosis due to hypovolaemic shock. A world record?

This case describes the unexpected survival of an adult man who presented to the emergency department with hypovolaemic shock secondary to a splenic haemorrhage. Before surgery he had a pH 6.527, base excess (BE) -34.2 mmol/l and lactate 15.6 mmol/l. He underwent a splenectomy after which his condition stabilised. He was managed in the intensive care unit postoperatively where he required organ support including renal replacement therapy but was subsequently discharged home with no neurological or renal deficit. Although there are case reports of patients surviving such profound metabolic acidosis these have mainly been cases of near drowning or toxic alcohol ingestion. To the best of our knowledge this is the first reported case of survival after a pH of 6.5 secondary to hypovolaemic shock.

Recovery from sedation with remifentanil and propofol, compared with morphine and midazolam, for reduction in anterior shoulder dislocation.

OBJECTIVE: To compare recovery from sedation using remifentanil and propofol with our standard regimen of morphine and midazolam for closed reduction in shoulder dislocation in an ED. METHODS: We randomised 40 patients for closed shoulder reduction to receive either remifentanil and propofol (R&P) (20 patients) or morphine and midazolam (M&M) (20 patients). A suitably trained ED doctor gave the sedation. R&P patients received oxygen from a tight-fitting facemask and Mapleson C circuit to prevent hypocapnia and thus reduce the risk of apnoea. Shoulder reduction was performed by another doctor with an ED nurse also present. We noted recovery times, pain and sedation scores, operative conditions, additional medication and adverse events. RESULTS: All patients given remifentanil and propofol had recovered within 30 min in contrast to the morphine and midazolam group where 17 of 20 patients had recovered after 60 min, the remainder requiring a total of 90 min. Median recovery times were 15 min (95% CI 15 to 20) for the remifentanil and propofol group, and 45 min (95% CI 29 to 48) for the morphine and midazolam group. Reduction conditions and scores for pain/distress did not differ between the groups. Seven patients required additional sedation (four R&P, three M&M) to enable shoulder reduction. Five patients (three R&P, two M&M) had received analgesia prior to the procedure from the ambulance service (one R&P, one M&M) and ED (two R&P). Two patients given morphine and midazolam required flumazenil to counter oversedation. CONCLUSIONS: Remifentanil and propofol reduces patient recovery time and provides equivalent operating conditions compared with morphine and midazolam for the reduction of anterior glenohumeral dislocation.

Effect of an integrated care pathway on acute asthma/wheeze in children attending hospital: cluster randomized trial.

OBJECTIVE: To determine whether an integrated care pathway (ICP) could improve care delivered to patients coming to an emergency department only or to patients who were subsequently admitted. STUDY DESIGN: Children (age, 2-16 years; n = 298) coming to the ED with acute asthma/wheeze, were randomized by using a cluster design to either standard care or care delivered by an ICP. RESULTS: Children discharged from the ED who received care with an ICP (n = 118) received more prednisolone (81%; standard, 63%; P = .03) and increased advice to obtain primary care review (72%; standard, 33%; P < .0001). A total of 180 children were admitted (94 ICP, 86 standard). The rate of recovery was unchanged by ICP. The mean ICP length of stay (37.6 hours; range, 33.5-42.4 hours), was 93% of the mean standard length of care (40.7 hours; range, 35.9-46; P = .36). When a discharge checklist was completed (60 of 94 cases), the mean ICP length of stay was 34.2 hours (range, 30.5-38.4 hours; P = .07 versus standard). An ICP resulted in a 30% reduction in prescribing errors (mean, 10.4; standard, 14.8; P = .002). Eighty-four of 94 children with an ICP received a 48-hour discharge plan (89%) versus 35 of 86 children with standard care (41%). More clinical contacts were observed in children receiving care by an ICP (mean, 22, versus standard, 19.2: P = .0004). CONCLUSION: An acute asthma/wheeze ICP improved education and prescribing errors, modestly reduced the length of stay when discharge criteria were adhered to, but did not influence recovery time. Further consideration of the effect on staff workload is required.

Is the 'LEMON' method an easily applied emergency airway assessment tool?

OBJECTIVE: To assess whether the 'LEMON' method, devised by the developers of the US National Emergency Airway Management Course, is an easily applied airway assessment tool in patients undergoing treatment in the emergency department resuscitation room. METHODS: One hundred patients treated in the resuscitation room of a UK teaching hospital between June 2002 and January 2003 were assessed on criteria based on the 'LEMON' method. RESULTS: All seven criteria of the 'Look' section of the method could be adequately assessed. Data for the 'Evaluate' section could not be obtained in 10 patients, with inter-incisor distance being the most problematical item. The 'Mallampatti' score was unavailable in 43 patients, and had to be assessed in the supine position in 32 of the remaining 57 patients. Assessment for airway 'Obstruction' and 'Neck mobility' could be performed in all patients. CONCLUSION: The 'Look', 'Obstruction' and 'Neck mobility' components of the 'LEMON' method are the easiest to assess in patients undergoing treatment in the emergency department resuscitation room. The 'Evaluate' and 'Mallampatti' components are less easily applied to the population that present to the resuscitation room, and assessment of these is more problematical and prone to inaccuracy. We suggest that the 'LEMON' airway assessment method may not be easily applied in its entirety to unselected resuscitation room patients, and that information on the 'Evaluate' and 'Mallampatti' parameters may not always be available.