Rescue Therapies in Patients with

Refractory Hypoxemia

Moreno Franco, Pablo M.D; Rachmale, Sonal M.D; Gregory, Wilson, R. R. T; Shifang, Ding M.D.; Anas Alsara, M.D. ; Li, Guangxi M.D

Mentor: Ognjen Gajic, M.D

RationaleRationaleRefractory hypoxemia (RH) represents a subgroup of acute hypoxemic respiratory failure patients who have failed conventional mechanical ventilation (MV) strategies and often need rescue therapiesRescue therapies include High Frequency Oscillation (HFO), ECMO (Extracorporeal Membrane Oxygenation), inhaled vasodilators (nitric oxide-iNO and inhaled prostacyclin- iPGI), and prone positioning

HypothesisHypothesis Use of rescue therapies is associated

with improved hospital mortality

MethodsMethods Cohort study Adult ICU patients requiring mechanical

ventilation from 2005 to 2009 Baseline demographics, risk factors,

severity of illness and outcomes were abstracted

Multivariate logistic regression analysis used to evaluate the association between rescue therapies and hospital mortality

Study Subjects SelectionStudy Subjects Selection First identified all patients with a First identified all patients with a

P/F ratio<175 on at least 2 P/F ratio<175 on at least 2 occasions occasions

Then we identified PEEP values Then we identified PEEP values within 2 hour range of first ABG with within 2 hour range of first ABG with P/F ratio < 175.P/F ratio < 175.

Study Subjects SelectionStudy Subjects Selection After calculating 2-component LIS, those with LIS < After calculating 2-component LIS, those with LIS <

3 were excluded 3 were excluded Tidal Volume and Plateau pressures within 2 hour Tidal Volume and Plateau pressures within 2 hour

range of first ABG with P/F ratio<175range of first ABG with P/F ratio<175 After calculating 3-component LIS, those with LIS < After calculating 3-component LIS, those with LIS <

3 were excluded3 were excluded

Study Subjects Study Subjects SelectionSelection

CXR done within 24 hours of first CXR done within 24 hours of first ABG with P/F ratio < 175 were ABG with P/F ratio < 175 were independently reviewed independently reviewed

Applying the University of Applying the University of Washington Chest Radiograph Washington Chest Radiograph Reading Protocol, number of Reading Protocol, number of quadrant score was obtained (From quadrant score was obtained (From 1-4) 1-4) (http://(http://depts.washington.edu/kclip/protocols.htmldepts.washington.edu/kclip/protocols.html) )

All ICU Patients Age>18 yearsfrom January 1st 2005-December 31 2009

n=65,831 No research authorization

n=2,184

Eligible Patientsn=63,647

Non=60,826

Mechanically Ventilated Patients P/F ratio ≤175 on at least 2 occasions *

LIS Score ≥3 on at least 1 occasion Refractory Hypoxemia

Yesn=2,821

Yes

n=826 First Instance of LIS Score ≥ 3 Identified as Time Zero “Refractory Hypoxemia”

Non=1,995

*Hypoxemia Score ≥3 on 2 occasions

Table 1. Patient characteristics associated to Rescue Therapies used in Patients with

Refractory Hypoxemia.

Refractory Hypoxemia (n)

Rescue Therapy (92)

No Rescue Therapy used

(734)p value

Median age in years (IQR)

54.2 (42.6-62.5)

62 (50.6-73.25) p<0.001

Female, n (%) (36) 39.1 (283) 38.5 p=0.4

Median 24 hour APACHE III

(IQR)99 (70-116) 97 (78-119) p=0.27

Median Sofa 24 hours (IQR)

9 (6-13) 9 (7-12) p=0.9

Median OI within 24 hours (IQR)

21 (13.8-29.1) 14.3 (9.6-20.9) p<0.0001

Median VD/VT (IQR)

0.61 (0.52-0.72)

0.59 (0.46-0.67) p=0.0009

ResultsResults

Type of therapy Combination Therapy ECMO

HFO i NO

i PGI Prone position

Chart 1. Distribution of Rescue Therapies used in Patients with Refractory Hypoxemia.

% o

f To

tal(N

o)

13.67%

7.19%

33.81%10.07%

14.39%

20.86%

Type of therapy

92 (11%) patients received at least one of the above rescue therapies

HFO only was used in 47, prone positioning in 29, iNO in 14, iPGI in 20 and ECMO in 10 patients.

Table 2. Outcomes associated to Rescue Therapies used in Patients with Refractory

Hypoxemia.

Refractory Hypoxemia (n)

Rescue Therapy (92)

No Rescue Therapy used

(734)p value

Hospital death, % (n) 53.2%, (49) 44.8 % (329) p=0.14

ICU death, % (n)44.5%, (41) 37.4% (275) p=0.2

Median Hospital LOS (IQR)

25.2 (13.9-46.5)

16.8 (8.7-31.3) p<.0001

Median ICU LOS (IQR)

15.1 (8.2-29.8)

9.1 (4.8-29.8) p<.0001

Median Mechanical

Ventilator Days (IQR)

11.5 (5.9-21.5)

6.5 (2.8-11.2) p<.0001

Table 3. Multivariate Logistic Table 3. Multivariate Logistic Regression Analysis for Regression Analysis for

Mortality with the Use of Mortality with the Use of Rescue TherapiesRescue Therapies

Odds Ratio (95% CI)

Use of Rescue Therapy 1.37 (0.86-2.18)

Median 24 hour APACHE III

1.01 (1.00-1.01)

Median OI 1.02 (1.01-1.04)

After adjusting by APACHE III and initial oxygenation index, rescue therapy did not improve hospital

mortality.

ConclusionConclusion

No difference in hospital mortality with use of RT in this populationRT were used in a minority of patients with RHThey were preferred for younger patients and worse hypoxemiaRT were associated with longer ICU and hospital stay

Special Thanks to:Special Thanks to:

Gregory, Wilson, R. R. T

Li, Guangxi M.D

Gajic, Ognjen M.D

Ongoing researchOngoing research

We have now gathered data from We have now gathered data from 2005-2010 and we are working on:2005-2010 and we are working on: Prognostic Model for Hospital Mortality Prognostic Model for Hospital Mortality

in RHin RH Propensity Scores for mortality with by Propensity Scores for mortality with by

various rescue therapies.various rescue therapies.

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