Monday October 13, 2008
Respiratory Failure Classification


Type I: Hypoxemic Failure (PaO2 < 60 at sea level)

Type II: Hypercapnic Failure (PCO2 > 45 mm hg)

Type III: Perioperative respiratory failure (increase atelectasis due to low functional residual capacity)

Type IV: Respiratory failure due to Shock. Type IV describes patients who are intubated and ventilated in the process of resuscitation for shock.

Sunday October 12, 2008
Silver-Coated Endotracheal Tubes decreases incidence of Ventilator-Associated Pneumonia?

Interesting study recently published in JAMA 1

Design, Setting, and Participants: Prospective, randomized, single-blind, controlled study from 54 centers in North America. A total of 2003 patients expected to require mechanical ventilation for 24 hours or longer were randomized.

Primary outcome measure: VAP incidence based on quantitative bronchoalveolar lavage fluid culture with 104 colony-forming units/mL or greater in patients intubated for 24 hours or longer.

Other outcomes measures: VAP incidence in all intubated patients, time to VAP onset, length of intubation and duration of intensive care unit and hospital stay, mortality, and adverse event.

Results

• Among patients intubated for 24 hours or longer, rates of microbiologically confirmed VAP were 4.8% (37/766 patients) in the group receiving the silver-coated tube and 7.5% (56/743) in the group receiving the uncoated tube, with a relative risk reduction of 35.9%
• The silver-coated endotracheal tube was associated with delayed occurrence of VAP
• No statistically significant between-group differences were observed in durations of intubation, intensive care unit stay, and hospital stay; mortality; and frequency and severity of adverse events

Conclusion: Patients receiving a silver-coated endotracheal tube had a statistically significant reduction in the incidence of VAP and delayed time to VAP occurrence compared with those receiving a similar, uncoated tube.



Reference: click to get abstract

Silver-Coated Endotracheal Tubes and Incidence of Ventilator-Associated Pneumonia, The NASCENT Randomized Trial , JAMA. 2008;300(7):805-813.

Saturday October 11, 2008

What is your Diagnosis?

Answer: Right bronchus intermedius intubation causing Right upper lobe atelectasis along with all of left lung collapse.

About 10% of ETT are initially placed in the right main stem bronchus. If tip is in bronchus intermedius, RUL will become atelectatic along with all of left lung.

Friday October 10, 2008

Q; What is Hemodialysis induced Vancomycin rebound phenomenon?

A; There is a rebound in vancomycin plasma concentrations at the end of the session. The plasma profile of vancomycin concentrations versus time indicates that concentrations decrease dramatically during the session and then increase when the session is stopped. This rebound may result from drug recirculation from plasma protein binding sites.

Clinical Significance: This rebound may be clinically significant, and it must be taken into account when determining vancomycin trough levels. It is recommended that determination of vancomycin trough levels in patients undergoing chronic haemodialysis should be performed before the haemodialysis session.

Reference: click to get abstract

Clinical review: Use of vancomycin in haemodialysis patients Crit Care. 2002; 6(4): 313–316

Thursday October 9, 2008
The feasibility of using ultrasound - for assessment of tracheal intubation / ruling out esophageal intubation

Wednesday October 8, 2008
Risk of death in ARDS - dead space fraction

Severity of hypoxemia, imaging and none of the single variable is predictive of risk of death in acute respiratory distress syndrome (ARDS) when measured early in the course of the disease. However the quintile of dead space fraction correlated well with later mortality in a few observational studies and in at least prospective study. The dead space fraction was independent risk factor for death.

dead-space fraction = (PaCO2 – PeCO2) ÷ PaCO2

PeCO2 is a mean expired carbon dioxide fraction and is measured with a bedside metabolic monitor. Metabolic monitoring (metabolic cart) is noninvasive and is used widely for metabolic and nutritional assessment.

Study Details

The dead-space fraction was prospectively measured in 179 intubated patients, a mean (±SD) of 10.9±7.4 hours after the ARDS had developed. Additional clinical and physiological variables were analyzed with the use of multiple logistic regression. The study outcome was mortality before hospital discharge.


Results

• The mean dead-space fraction was markedly elevated (0.58±0.09) early in the course of the ARDS and was higher among patients who died than among those who survived (0.63±0.10 vs. 0.54±0.09)
• The dead-space fraction was an independent risk factor for death: for every 0.05 increase, the odds of death increased by 45 percent
• The only other independent predictors of an increased risk of death were the Simplified Acute Physiology Score II, an indicator of the severity of illness and quasistatic respiratory compliance

Conclusions: Increased dead-space fraction is a feature of the early phase of the acute respiratory distress syndrome. Elevated values are associated with an increased risk of death



Pulmonary Dead-Space Fraction as a Risk Factor for Death in the Acute Respiratory Distress Syndrome - NEJM,Volume 346:1281-1286, Number 17, April 25, 2002

Tuesday October 7, 2008
Predicted body weights

The mantra of "low tidal volume" in ARDS is based on predicted body weight. This is a calculation based on age, gender and height.

Predicted body weight for men:

50 + (2.3 x [height in inches - 60])
or
50 + (0.91 x [height in centimeters - 152.4])

.

Predicted body weight for women:

45 + (2.3 x [height in inches - 60])
or
45 + (0.91 x [height in centimeters-152.4])

Reference: http://www.ardsnet.org/node/77460