On pandemics and the duty to care: whose duty? who cares?

Background  

As a number of commentators have noted, SARS exposed the vulnerabilities of our health care systems and governance structures. Health care professionals (HCPs) and hospital systems that bore the brunt of the SARS outbreak continue to struggle with the aftermath of the crisis. Indeed, HCPs – both in clinical care and in public health – were severely tested by SARS. Unprecedented demands were placed on their skills and expertise, and their personal commitment to their profession was severely tried. Many were exposed to serious risk of morbidity and mortality, as evidenced by the World Health Organization figures showing that approximately 30% of reported cases were among HCPs, some of whom died from the infection. Despite this challenge, professional codes of ethics are silent on the issue of duty to care during communicable disease outbreaks, thus providing no guidance on what is expected of HCPs or how they ought to approach their duty to care in the face of risk.     

Time series analysis of age related cataract hospitalizations and phacoemulsification

Background  

Cataract surgery remains a commonly performed elective surgical procedure in the aging and the elderly. The purpose of this study was to utilize time series methodology to determine the temporal and seasonal variations and the strength of the seasonality in age-related (senile) cataract hospitalizations and phacoemulsification surgeries.     

Simplicity within complexity: Seasonality and predictability of hospital admissions in the province of Ontario 1988–2001, a population-based analysis

Background  

Seasonality is a common feature of communicable diseases. Less well understood is whether seasonal patterns occur for non-communicable diseases. The overall effect of seasonal fluctuations on hospital admissions has not been systematically evaluated.     

Discrimination of normal and abnormal prothrombin and protein C in plasma using a calcium ion-inhibited monoclonal antibody to a common epitope on several vitamin K-dependent proteins

Vitamin K deficiency or administration of vitamin K antagonists results in the biosynthesis of abnormal des-gamma-carboxy forms of the vitamin K-dependent proteins. Monoclonal antibody H-11 binds several vitamin K- dependent proteins at a determinant that includes the first two residues of gamma-carboxyglutamic acid. Antibody H-11 binds fully carboxylated prothrombin and protein C in the presence of EDTA but binding is inhibited by the divalent metal ions, calcium, magnesium, and manganese. By contrast, des-gamma-carboxy prothrombin and protein C bind antibody H-11 the same in the presence of EDTA or calcium ion. Antibody H-11 thus appears to bind a conserved antigenic site containing gamma-carboxyglutamic acid that in the presence of divalent metal ion undergoes a conformational transition. This ability of antibody H-11 to bind des-gamma-carboxy prothrombin and protein C in the presence of calcium ion allowed the development of an immunoassay for these proteins in plasma. Prothrombin and protein C from stably anticoagulated individuals receiving warfarin were characterized by their ability to bind antibody H-11 in the presence of calcium ion. Binding of prothrombin and protein C to antibody H-11 in the presence of calcium correlated temporally with warfarin administration. The inability of calcium ion to inhibit binding of antibody H-11 to abnormal prothrombin and protein C in plasma suggests that the circulating forms of both proteins following warfarin administration cannot undergo the metal ion-dependent conformational transition that includes sequence residues 1 through 12.     

Airway pressure and transpulmonary pressure during high-frequency oscillation for acute respiratory distress syndrome

High-frequency oscillation is a novel form of ventilation increasingly being used to treat refractory hypoxic respiratory failure resulting from acute lung injury or acute respiratory distress syndrome. Although there is no known relationship between airway pressure and transpulmonary pressure during conventional mechanical ventilation, no study has attempted to determine transpulmonary pressure during high-frequency oscillation.

BACKGROUND:

High-frequency oscillation (HFO) is used for the treatment of refractory hypoxic respiratory failure.

OBJECTIVE:

To demonstrate that the mean transpulmonary pressure (P_L) cannot be inferred from mean airway pressure (mPaw).

METHODS:

In seven patients already undergoing HFO for refractory acute respiratory distress syndrome, esophageal pressure (Pes) was measured using an esophageal balloon catheter. Pleural pressure (Ppl) and P_L were calculated from Pes.

MAIN RESULTS:

In the seven patients (mean [± SD] age 59±9 years) treated with HFO at 5±1 Hz and amplitude 75±10 cmH₂O, the mPaw was 27±6 cmH₂O, Ppl was 9±6 cmH₂O and P_L was 18±11 cmH₂O. Successful catheter placement and measurement of Pes occurred in 100% of subjects. There was no correlation between P_L and mPaw. The majority of subjects required hemodynamic support during the use of HFO; the frequency and degree of support during the study period was no different than that before the study.

CONCLUSION:

The present report is the first to describe measuring Pes and calculating Ppl during HFO for acute respiratory distress syndrome. While both current guidelines and recent trials have titrated treatment based on mPaw and oxygenation, there is wide variability in P_L during HFO and P_L cannot be predicted from mPaw.