A Canadian survey of perceptions and practices related to ordering of blood tests in the intensive care unit

PURPOSE

The ordering of routine blood test panels in advance is common in intensive care units (ICUs), with limited consideration of the pretest probability of finding abnormalities. This practice contributes to anemia, false positive results, and health care costs. We sought to understand practices and attitudes of Canadian adult intensivists regarding ordering of blood tests in critically ill patients.

METHODS

We conducted a nationwide Canadian cross-sectional survey consisting of 15 questions assessing three domains (global perceptions, test ordering, daily practice), plus 11 demographic questions. The target sample was one intensivist per adult ICU in Canada. We summarized responses using descriptive statistics and present data as mean with standard deviation (SD) or count with percentage as appropriate.

RESULTS

Over seven months, 80/131 (61%) physicians responded from 77 ICUs, 50% of which were from Ontario. Respondents had a mean (SD) clinical experience of 12 (9) years, and 61% worked in academic centres. When asked about their perceptions of how frequently unnecessary blood tests are ordered, 61% responded "sometimes" and 23% responded "almost always." Fifty-seven percent favoured ordering complete blood counts one day in advance. Only 24% of respondents believed that advanced blood test ordering frequently led to changes in management. The most common factors perceived to influence blood test ordering in the ICU were physician preferences, institutional patterns, and order sets.

CONCLUSION

Most respondents to this survey perceived that unnecessary blood testing occurs in the ICU. The survey identified possible strategies to decrease the number of blood tests.

Performances and limits of Bag-Valve-Device for pre-oxygenation and manual ventilation: A comparative bench and cadaver study

INTRODUCTION

Bag-Valve-Device (BVD) is the most frequently used device for pre-oxygenation and ventilation during cardiopulmonary resuscitation (CPR). A minimal expired fraction of oxygen (FeO2) above 0.85 is recommended during pre-oxygenation while insufflated volume (VTi) should be reduced during manual ventilation. The objective was to compare the performances of different BVD in simulated conditions.

METHODS

Nine BVD were evaluated during pre-oxygenation: spontaneous breathing patients were simulated on a test lung (mild and severe conditions). FeO2 was measured with and without positive end-expiratory pressure (PEEP). CO2 rebreathing was evaluated. Then, manual ventilation was performed by 36 caregivers (n = 36) from three hospitals on a specific manikin; same procedure was repeated by 3 caregivers (n = 3) on two human cadavers with three of the nine BVD: In non-CPR scenario and during mechanical CPR with Interrupted Chest Compressions strategy (30:2).

RESULTS

Pre-oxygenation: FeO2 was lower than 0.85 for three BVD in severe condition and for two BVD in mild condition. FeO2 was higher than 0.85 in eight of nine BVD with an additional PEEP valve (PEEP 5 cmH2O). One BVD induced CO2 rebreathing. Manual ventilation: For non-CPR manual ventilation, mean VTi was within the predefined lung protective range (4-8 mL/kg PBW) for all BVD on the bench. For CPR manual ventilation, mean VTi was above the range for three BVD on the bench. Similar results were observed on cadavers.

CONCLUSIONS

Several BVD did not reach the FeO2 required during pre-oxygenation. Manual ventilation was significantly less protective in three BVD. These observations are related to the different BVD working principles.

The First 2 Years of Activity of a Specialized Organ Procurement Center: Report of an Innovative Approach to Improve Organ Donation

The number of patients requiring organ transplants continues to outgrow the number of organs donated each year. In an attempt to improve the organ donation process and increase the number of organs available, we created a specialized multidisciplinary team within a specialized organ procurement center (OPC) with dedicated intensive care unit (ICU) beds and operating rooms. The OPC was staffed with ICU nurses, operating room nurses, organ donor management ICU physicians, and multidisciplinary staff. All organ donors within a designated geographic area were transferred to and managed within the OPC. During the first 2 years of operation, 126 patients were referred to the OPC. The OPC was in use for a total of 3527 h and involved 253 health workers. We retrieved 173 kidneys, 95 lungs, 68 livers, 37 hearts, and 13 pancreases for a total of 386 organs offered for transplantation. This translates to a total of 124.6 persons transplanted per million population, which compares most favorably to recently published numbers in developed countries. The OPC clearly demonstrates potential to increase the number of deceased donor organs available for transplant. Further studies are warranted to better understand the exact influence of the different components of the OPC on organ procurement.

Anti-apolipoprotein A-1 IgG in patients with myocardial infarction promotes inflammation through TLR2/CD14 complex

OBJECTIVES

Toll-like receptor (TLR)-mediated vascular inflammation, inducible by - amongst other factors - auto-antibodies, is increasingly recognized as a potential mediator of cardiovascular disease. We investigated whether anti-apolipoprotein (Apo)A-1 IgG was associated with a pro-inflammatory cytokine profile in myocardial infarction (MI) patients and whether anti-ApoA-1 IgG elicited a pro-inflammatory response by activating TLRs.

METHODS

As surrogate markers of atherosclerotic plaque vulnerability, interleukin (IL)-6, tumour necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-9 and MMP-3 levels were assessed in 221 consecutive MI patients. Using human monocyte-derived macrophages (HMDMs) we investigated (i) the anti-ApoA-1 IgG interaction with TLRs using proximity ligation assay and (ii) anti-ApoA-1 IgG-dependent IL-6/TNF-α production. TLR involvement was further confirmed using HEK293-Blue TLR-2/-4 cells and by computational docking simulations.

RESULTS

In MI patients, anti-ApoA-1 IgG positivity was associated with higher levels of IL-6, TNF-α and MMP-9, but lower MMP-3 levels. In in vitro experiments, anti-ApoA-1 antibodies bound to HDMDs in a TLR2-dependent manner, resulting in nuclear translocation of NFκB and a significant increase in TNF-α and IL-6 production. Subsequent functional studies highlighted the importance of CD14 as co-receptor in the anti-ApoA-1 IgG-TLR2-induced cytokine production. Additional bioinformatic studies identified structural homologies between TLR2 and ApoA-1, which may explain the observed cross-reactivity between antibodies against these two molecules.

CONCLUSIONS

Anti-ApoA-1 IgG positivity in MI is associated with a high-risk cytokine profile. These auto-antibodies promote inflammation by stimulating the TLR2/CD14 receptor complex, probably because of molecular mimicry, which may contribute to atherosclerosis-related complications in patients.

[Acute chest syndrome in sickle cell disease and acute respiratory distress syndrome--from pathophysiology to therapy]

Acute chest syndrome is frequent in the homozygous sickle cell disease population. It can evolve to an acute respiratory distress syndrome. Pulmonary artery hypertension or chronic lung sequellae are common. The vasoocclusive phenomenon is due to capillary blockade, followed by an activation of inflammation, and adhesion phenomena further increasing the damage. Decreased blood oxygenation leads to an aggravation of the sickle crisis. Nitric oxide disregulation has been recently highlighted. Diagnosis must be suspected in patients presenting with sickle crisis, fever, low blood oxygenation and lung infiltrates. Early antibiotherapy, adequate oxygenation, blood transfusion and erythrocytapheresis are key points for management. Preventive measures such as iterative transfusion-chelation, hydroxyurea or repetitive erythrocytapheresis are all useful.