Pulmonary Disorders I

Recently published clinical practice guidelines strongly recommend prone positioning in moderate

overwhelming support for this therapy in ARDS, several important questions remain, including the

optimal duration and timing of use pertaining to ARDS onset. Patients with ARDS should remain

in the prone position for more than 12 hours each day, with consideration for longer daily durations

(i.e., at least 16 hours per day). Prone positioning therapy should be considered early in the course

of ICU admission in patients with moderate to severe ARDS.

Source

Summary

GRADE Recommendation

2017;195:1253-63

Suggest prone positioning > 12 hr/day

Strong recommendation; moderate-

high level of evidence

BMJ Open

Respir Res

2019;6:e000420

severe ARDS (i.e., Pao2/Fio2 < 150 mm Hg)

Strongly in favor

Care 2019;9:69

Should be used in moderate to severe ARDS (Pao2/

Fio2 < 150 mm Hg) for at least 16 consecutive hr

High level of evidence

Intensive

2023;49:727-59

Recommend using early after intubation in moderate

to severe ARDS (Pao2/Fio2 < 150 mm Hg for at least

16 consecutive hours)

Strong recommendation; high level of

evidence

Extracorporeal membrane oxygenation (ECMO)

The CESAR trial showed that treatment at an ECMO referral center improved 6-month survival

ARDS with a Murray score (i.e., acute lung injury score on the basis of chest radiography,

hypoxemia score, peak end-expiratory pressure, and static compliance) of 3 or greater, or

hypercapnia and a pH less than 7.20

ii.

Not all patients randomized to the ECMO referral center received ECMO (around 24% of

patients in the experimental group did not receive ECMO).

iii.

Potential for confounding because of experiential bias – Clinicians at an ECMO treatment

center may have more experience in treating ARDS.

The Respiratory ECMO Survival Prediction (RESP) score was developed from a registry of patients

The RESP score predicts patient survival after ECMO initiation.

ii.

Does not help quantify the decision to initiate ECMO or determine if ECMO treatment will

improve survival in a specific patient

In the EOLIA trial, early use of ECMO compared with conventional management in severe ARDS

(e.g., Pao2/Fio2 less than 80 mm Hg) was not associated with reduced 60-day mortality rates (relative

risk [RR] 0.76; 95% CI, 0.55–1.04, p=0.09) (N Engl J Med 2018;378:1965-75).

This trial was prematurely discontinued because of predefined futility criteria, which resulted

in not achieving power.

ii.

Furthermore, bias was attributed to the high crossover rate of 28% of controls into the ECMO

group.