Effectiveness of Selected Air Cleaning Devices During Dental Procedures.

INTRODUCTION: The recent COVID-19 pandemic has underscored the necessity of protecting health care providers (HCPs) against the transmission of infectious agents during dental procedures. To this end, the effectiveness of several air cleaning devices (ACDs) in reducing HCPs exposure to aerosols generated during dental procedures was estimated, separately or in combination with each other. These ACDs were a chairside unit capturing aerosols at the source of generation, and four ambient ACDs: a portable ambient ACD; a negative pressure module; a custom made, fan-operated and wall-mounted air filter (WMAF); and a smaller and passive version of the latter. The last three ACDs were intended for mobile dental clinics (MDCs) only. MATERIALS AND METHODS: This assessment was performed in two different environments: in a dental clinic operatory and in a MDC. Two dental personnel, acting in the roles of dentist and dental assistant, performed on simulated patient aerosol-generating and non-aerosol-generating procedures. For each 5-minute scenario, the cumulative exposure to airborne particulate matter 10 µm in size or smaller (PM10) was determined by calculating the sum of all 1 second readings obtained with personal and ambient air monitors. The effectiveness of the ACDs in capturing PM10 was estimated based on the capability of the ACDs to keep PM10 level at or below the initial background level. RESULTS: In all conditions assessed in the dental clinic operatory, when both the chairside and portable ambient ACDs were functioning, an estimated effectiveness of 100% in capturing PM10 was achieved. In the MDC, in all conditions where the chairside ACD was used without the negative pressure module, an estimated effectiveness of 100% was also achieved. The simultaneous operation of the negative pressure module in the MDC, which led to a room negative pressure of -0.25 inch wc, reduced the chairside ACD's effectiveness in capturing aerosols. Conversely, the use of the WMAF in the MDC in combination with the chairside ACD further reduced exposure to PM10 below the initial background level. Nonetheless, in all conditions assessed in both settings (dental clinic operatory and MDC), larger visible aerosols were produced, often landing on the surrounding environment. A fair portion of these aerosols landed on the inside of the chairside ACD flange. CONCLUSIONS: This assessment suggests that the use of the tested chairside ACD, by capturing aerosols at the source of generation, had the greatest impact on reducing exposure of dental personnel to PM10 produced during dental procedures. This study also indicates that such exposure is further reduced with the addition of an ambient ACD. However, creating a negative pressure room as high as -0.25 inch wc can lead to air turbulence reducing the effectiveness of ACDs in capturing aerosols at the source. Furthermore, the presence of uncaptured droplets and spatter on the surrounding environment supports the need to complement the use of engineering controls with proper administrative controls and personal protective equipment, as recommended by governmental agencies and the scientific community for preventing the transmission of infection in health care settings.

Outbreak of hemolytic uremic syndrome with unusually severe clinical presentation caused by Shiga toxin-producing Escherichia coli O26:H11 in France.

BACKGROUND: In spring 2019, an outbreak of Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC HUS) occurred in France. Epidemiological investigations made by Santé publique France in connection with microbiological investigations at the national reference center for STEC promptly identified a common exposure to consumption of raw cow's milk cheese, and confirmed a cluster affiliation of the E. coli O26:H11 outbreak strain. Here, we report the clinical characteristics of the patients, the treatment used, as well as the outcome at 1 month. METHOD: Patients with STEC HUS linked to the E. coli O26:H11 outbreak strain were identified from the national surveillance network of pediatric STEC HUS cases coordinated by Santé publique France. Clinical data were analyzed from the patients' hospital records obtained from the treating physicians. RESULTS: Overall, 20 pediatric cases of STEC HUS linked to the outbreak strain were identified. Their median age of the patients was 16 months (range: 5-60). Most of them presented with diarrhea but none had received prior antibiotherapy. A total of 13 patients required dialysis; 10 patients and four patients had central nervous system (CNS) and cardiac involvement, respectively. No deaths occurred. At the 1-month follow-up, only two patients had a decreased glomerular filtration rate, below 80 mL /min/1.73m2 and four had hypertension. One patient had neurological sequelae. CONCLUSION: The E. coli O26:H11 strain identified as the cause of an STEC HUS outbreak in France in spring 2019 is notable for the initial severe clinical presentation of the patients, with a particularly high frequency of CNS and cardiac involvement similar to the German E. coli O104:H4 outbreak described in 2011. However, despite the initial severity, the 1-month outcome was favorable in most cases. The patients' young age in this outbreak highlights the need to improve information and caregiver awareness regarding consumption of at-risk foods by young children as key preventive measures against STEC infections.

[Management of hyperbilirubinemia of the term newborn in maternity wards]. / Prise en charge de l'hyperbilirubinémie du nouveau-né à terme en maternité.

Jaundice is a frequent clinical sign among healthy term newborns. A rigorous clinical assessment is crucial in order to recognise haemolytic, infectious and metabolic diseases. The use of the transcutaneous jaundice-meter in decision-making, and the phototherapy principles and applications, are discussed. Intensive phototherapy allows a rapid decrease in plasma bilirubin levels, so that it may used to treat even severe hyperbilirubinemia in the maternity ward.

Serum magnesium and potassium in acute myocardial infarction. Influence on ventricular arrhythmias.

Over a 13-month period, serum potassium and magnesium levels were measured in 590 patients admitted to a coronary care unit. Hypokalemia, often in the absence of diuretic use, occurred in 17% of the 211 patients with acute myocardial infarction. Patients with acute myocardial infarction and a potassium level of less than 4.0 mEq/L (4.0 mmol/L) had an increased risk of ventricular arrhythmias (59% vs 42%). Because hypokalemia is common in acute myocardial infarction and is associated with ventricular arrhythmias, routine measurement of serum potassium levels and prompt correction are recommended. Hypomagnesemia occurred in only 4% of the patients, but it was more common in the group with acute myocardial infarction than in the group without myocardial infarction (6% vs 3%). Ventricular arrhythmias occurred in ten of the 13 patients with both acute myocardial infarction and hypomagnesemia, but eight of these patients also had low serum potassium levels. This low incidence of hypomagnesemia does not justify routine measurement of serum magnesium levels. However, the mean level (2.5 +/- 0.4 mg/dL [1.03 +/- 0.16 mmol/L]) in a reference population of healthy volunteers was unexpectedly high and suggests that the low incidence of hypomagnesemia in our population may not be applicable to other centers and may reflect a higher magnesium content in our geographic area of southeastern Ontario.

[Hyperoxemia in extracorporeal circulation]. / Hyperoxémie en circulation extra-corporelle

The authors demonstrate the effects of hyperoxemia in dogs subjected to extracorporeal circulation. Arterial Po2 was maintained between 100 and 140 mm Hg in a control group and above 200 mm Hg in another group. There was no morbidity or mortality in these experiments. Postoperative functional status as well as hematological and biochemical data were similar in both groups. However, free plasma hemoglobin was 50% higher in animals subjected to hyperoxygenation. It is thus concluded that on the basis of these results hyperoxygenation has no beneficial effect on the animals submitted to total body bypass and moreover that arterial Po2 over 200 mm Hg increases hemolysis.