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www.thelancet.com/respiratory Published online April 25, 2013 http://dx.doi.org/10.1016/S1473-3099(13)70111-7 1

Beyond pneumonia: improving care for ventilated patients

In the ongoing quest to improve care for ventilated

patients, a thorough understanding of the potential

hazards faced by this population is indispensible. Merely

knowing which harms might befall these patients is

not suffi cient. Understanding their relative frequencies

and severities is crucial to inform complete and cost

effective prevention strategies. Accurately measuring

the frequency and severity of harms, however, is

surprisingly complicated. Estimating frequency is

hindered by the subjectivity and limited accuracy of

definitions for conditions such as ventilator-associated

pneumonia, sepsis, acute respiratory distress syndrome,and thromboembolic disease. Estimating attributable

morbidity and mortality is hindered by the diffi culty

disentangling the independent contributions of the

complication of interest, patients underlying illnesses,

time spent in hospital and on mechanical ventilation

before developing the complication, and concurrent

additional hazards of critical care.

Investigators have developed several sophisticated

statistical strategies to adjust for these potential

confounders. These include matching protocols,

multistate models, and marginal structural models.15

In The Lancet Infectious Diseases, however, WilhelminaMelsen and colleagues present an innovative and clinically

intuitive method6 that takes advantage of data from

randomised controlled trials to estimate the attributable

mortality of ventilator-associated pneumonia and to

tease apart the relative contributions of pneumonia

versus prolonged intensive care to mortality risk.

Melsen and colleagues6 estimated mortality

associated with ventilator-associated pneumonia by

assessing the extent to which prevention measures

can lower ventilator-associated pneumonia rates

and intensive care unit (ICU) mortality rates. Theypooled together data from 6284 individuals enrolled

in 24 randomised trials of different ventilator-

associated pneumonia prevention interventions. The

pooled interventions lowered ventilator-associated

pneumonia rates by 30% overall (95% CI 2138)

and ICU mortality by 4% (6 to 12). They therefore

estimated that if one were theoretically able to

eliminate 100% of ventilator-associated pneumonias

that ICU mortality would decrease by 13% (4%

multiplied by 100% divided by 30%). This finding

implies that only 13% of the mortality risk in ICU

patients is due to ventilator-associated pneumonia.

Although this low figure probably reflects the

beneficial impacts of antibiotic therapy, it is

nonetheless sobering and alerts us that we need to

look beyond pneumonia prevention alone to make

further substantive effects on ICU mortality.

Melsen and colleagues1 also completed a competing

risks analysis that sheds light on the relative contribution

of ventilator-associated pneumonia itself versus

general complications of intensive care on patients

prognoses. The competing risks analysis enabledthe authors to estimate the impacts of ventilator-

associated pneumonia on intensive care length of stay

and mortality both independently and in combination.

They showed that ventilator-associated pneumonia

decreased the daily probability of discharge from the

ICU by 26% (95% CI 2032), indicating that the disorder

extends length of stay in the ICU. The ventilator-

associated pneumonia cause-specific hazard ratio (HR)

of dying in the ICU was 113 (95% CI 098131) but

combining the effect of prolonged length of stay with

the ventilator-associated pneumonia cause-specific

mortality increased the estimated mortality HR to 220(191254). This implies that most of the mortality

noted in patients with ventilator-associated pneumonia

is due to extra time spent in the ICU rather than directly

due to the condition itself.

This observation carries important lessons for

prevention. We learn that extended time spent in

the ICU is hazardous in patients with and without

ventilator-associated pneumonia and that interventions

that can decrease length of stay are probably potent

strategies to mitigate both non-specific and ventilator-

associated pneumonia-specific ICU mortality. In thisregard, Melsen and colleagues analysis anticipates the

the US Centers for Disease Control and Preventions

(CDC) new definitions for ventilator-associated event

surveillance.7 CDCs new definitions deliberately broaden

the focus of routine surveillance from pneumonia alone

to complications of mechanical ventilation in general in

recognition that ventilated patients are at risk for many

severe complications in addition to pneumonia.

Both Melsen and colleagues analyses and CDCs new

definitions challenge us to enlarge our vision of what

MichaelKlompas

Published Online

April 25, 2013

http://dx.doi.org/10.1016/

S1473-3099(13)70111-7

See Online/Articles

http://dx.doi.org/10.1016/

S1473-3099(13)70081-1

7/27/2019 Beyond Pneumonia

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Comment

2 www.thelancet.com/respiratory Published online April 25, 2013 http://dx.doi.org/10.1016/S1473-3099(13)70111-7

it takes to improve outcomes for patients in ICUs.

Interventions focused solely on preventing ventilator-

associated pneumonia alone are not suffi cient.

General strategies that expedite extubation and ICU

discharge merit prioritisation. In this light, improved

sedative management, ventilator weaning, and early

mobilisation protocols deserve special mention.

These interventions have repeatedly been shown to

decrease duration of mechanical ventilation, length of

stay in intensive care, long-term functional outcome,

and sometimes even mortality.813 These potent

interventions are the means to help translate Melsen

and colleagues insights into better outcomes for

mechanically ventilated patients.

*Michael Klompas, Lingling LiDepartment of Population Medicine, Harvard Medical School and

Harvard Pilgrim Health Care Institute, 133 Brookline Avenue,

Boston MA 02215, USA (MK, LL); Department of Medicine,

Brigham and Womens Hospital, Boston, MA (MK)

mklompas@partners.org

MK has received honoraria from Premier Healthcare Alliance for lectures on VAP

surveillance. LL declares that shehas no conflicts of interest.

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2 Nguile-Makao M, Zahar JR, Francais A, et al. Attributable mortality ofventilator-associated pneumonia: respective impact of main characteristics

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