Age and Ageing
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Acute respiratory failure in the elderly: diagnosis
SAMUEL DELERME, PATRICK RAY
Emergency Department, CHU Piti´ e-Salp´ etriˆ ere, 47-83 boulevard de l’hopital, 75013 Paris, Universit´ e Pierre et
Marie Curie-Paris 6, France
Address correspondence to: P. Ray. Tel: +33 1 42 17 72 42; Fax: +33 1 42 17 72 64. Email: email@example.com
Acute respiratory failure (ARF) in patients over 65 years is common in emergency departments (EDs) and is one of the key
symptoms of congestive heart failure (CHF) and respiratory disorders. Searcheswere conducted in MEDLINE for published
studies in the English language between January 1980 and August 2007, using ‘acute dyspnea’, ‘acute respiratory failure
(ARF)’, ‘heart failure’, ‘pneumonia’, ‘pulmonary embolism (PE)’ keywords and selecting articles concerning patients aged
65 or over. The age-related structural changes of the respiratory system, their consequences in clinical assessment and the
pathophysiology of ARF are reviewed. CHF is the most common cause of ARF in the elderly. Inappropriate diagnosis that is
frequent and inappropriate treatments in ED are associated with adverse outcomes. B-type natriuretic peptides (BNPs) help
with CHF or acidotic chronic obstructive pulmonary disease (COPD) who do not improve with medical treatment. Further
studies on ARF in elderly patients are warranted.
Keywords: acute respiratory failure, elderly, pulmonary embolism, BNP, congestive heart failure
Visits by older adults compose 12–21% of all emergency
department (ED) encounters . Furthermore, studies
showed a progressive increase in the number of ED
attendances and emergency admissions hospital of older
patients in the last decade. Between 30 and 50% of all ED
visits by older patients result in a hospital admission. Lastly
when admitted, older emergency patients are more likely to
failure (ARF) is a common complaint of elderly patients in
ED, and the key clinical presentation of cardiac [congestive
heart failure (CHF)] and respiratory disorders .
This article will summarise the age-related structural
changes of the respiratory system and their consequences in
clinical practice. It will also overview the causes, difficulties
in diagnosis, treatment and the prognosis of ARF in elderly
Searches were conducted in MEDLINE for published
studies in the English language between January 1980 and
‘heart failure’, ‘pneumonia’, ‘pulmonary embolism (PE)’
keywords and selecting articles concerning patients aged
65 or over.
Physiological changes according to age
Several changes related to ageing need to be taken into
account before discussing ARF.
Chest wall compliance decreases progressively with age,
presumably related to structural changes within the rib
cage [4, 5].
Total lung capacity does not change with age, but the
functional residual capacity and the residual volume both
increase. There is an increased tendency in airway closure
at small volumes (senile emphysema) related to the loss
of supporting tissues around the airways . Because a
to gas exchange (low V/Q ratio) zones, but also because of
a reduced alveolar area, ageing was classically thought to be
accompanied by a progressive decline in arterial oxygen
tension (PaO2). Actually, recent studies have found no
significant correlation between PaO2and age . Because of
Age and Ageing Advance Access published April 3, 2008
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S. Delerme and P. Ray
a decline in tests of forced expiration (i.e. increasing airway
who are non-smokers. Furthermore, studies suggest that
the ß-adrenoceptor dysfunction explains a less response to
bronchodilation in older asthmatic patients .
Other common important changes include loss of
diaphragmatic mass and strength with age . Finally, as
a consequence of poor nutritional status, decreased T-cell
function, decline in mucociliary clearance, poor dentition
(Parkinson’s disease, Alzheimer’s disease and stroke),
community-acquired (CAP) and aspiration pneumonia is
exceedingly common in elderly patients .
Furthermore, decreased sensitivity of respiratory centres
to hypoxaemia, hypercapnia, or added resistive loads will
result in a diminished ventilatory response in cases of ARF;
and could delay diagnosis because of the poor perception of
the respiratory insults .
The physiological cardiovascular changes involve the
flow reserve, ventricular compliance and ß-adrenoceptor-
mediated modulation of inotropy.
The ageing heart increases cardiac output by increasing
stroke volume rather than increasing heart rate. However,
this compensatory mechanism is dependent on the effective
patient) . This explains the frequency of CHF caused by
rapid atrial fibrillation in the elderly.
Cardiac and respiratory systems are dependent. For
example, (1) a bout of pneumonia is sufficient to trigger
an acute exacerbation of heart failure, (2) a reduction in
cardiac output accompanying septic shock is a cause of
ARF causedby diaphragmhypoperfusion leading to alveolar
hypoventilation, and respiratory arrest.
Other relevant changes
Decrease in glomerular filtration rate (approximately 45%
by the age of 80) with ageing has important implications in
terms of drug dosing, as most drugs are renally excreted .
Most studies have shown an imbalance between
procoagulant/antifibrinolytic and anticoagulant factors,
which could contribute to an increased incidence of PE.
Definition and pathophysiology of acute
The respiratory system consists of two parts: the lung, i.e.
the gas-exchanging organ, and the pump . The pump
consists of the chest wall, including the respiratory muscles
(essentially the diaphragm), the respiratory controllers in
the central nervous system and the pathways that connect
the central controllers with the respiratory muscles (spinal
and peripheral nerves). ARF is a condition in which the
respiratory system fails in one or both of its gas exchange
functions, i.e. oxygenation (PaO2<60 mmHg) of and/or
(PaCO2) >45 mmHg) . Both cut-off values simply serve
as a general guide in combination with the history and
clinical assessment of the patient. Thus, ARF could also be
suspected by ‘simple’ clinical criteria: polypnea>30 per min,
contraction of the accessory inspiratory muscles, abdominal
respiration, orthopnea cyanosis, and asterixis. Orthopnea is
frequently associated with all causes of ARF, and is neither a
sensible nor specific predictor of CHF .
The four pathophysiological mechanisms related to
hypoxaemic ARF (1) ventilation/perfusion inequality which
is the main mechanisms in an emergency setting (CHF or
pneumonia), (2) increased shunt (acute respiratory distress
syndrome), (3) alveolar hypoventilation [chronic obstructive
pulmonary disease (COPD)], and (4) diffusion impairment
(pulmonary fibrosis) .
Failure of the pump (or ventilatory failure) results in
Mechanisms responsible are decreasing minute ventilation
and increasing dead space. In elderly patients, the major
cause is severe hyperinflation, with flattened diaphragm and
Actually, hypoxaemic ARF is a situation accompanied by
increased work of breathing. However, energy availability is
reduced due to hypoxaemia, resulting in muscle fatigue and
Table 1. Principal causes of acute respiratory failure
(adapted from )
Decreased central drive
Morphine (or other drugs: sedatives)
Central nervous system diseases (encephalitis, stroke, trauma)
Altered neural and neuromuscular transmission
Spinal cord trauma, transverse myelitis, tetanus, amyotrophic lateral
sclerosis, poliomyelitis, Guillain–Barre’ syndrome
Myasthenia gravis, botulism
Muscular dystrophy, disuse atrophy
Chest wall and pleural abnormalities
Chest wall trauma (flail chest, diaphragmatic rupture)
Lung and airways diseases
Acute exacerbation of chronic obstructive pulmonary disease
Congestive heart failure and non-cardiogenic pulmonary oedema
(acute respiratory distress syndrome)
Upper airways obstruction
Lung cancer, pulmonary fibrosis
Pneumothorax, pleural effusion
Severe sepsis or septic shock, other shock
The main causes of ARF in elderly patients are in bold.
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ARF in the elderly: diagnosis and prognosis
ventilatory failure through imbalance between demand and
ARF in elderly patients
Etiology of ARF
The EPIDASA study prospectively evaluated ARF in 514
patients (mean age of 80 years), presenting to the ED.
CHF (43%), pneumonia (35%), COPD exacerbation (32%),
and PE (18%) were the main causes . Half of the
patients had more than two diagnoses (CHF and CAP
in 17%). Pneumothorax, lung cancer, severe sepsis and
acute asthma were less frequent (<5%). An autopsy study
of 234 elderly patients confirmed that the most common
causes of death were CAP and CHF, both frequently
underestimated . Ely et al. reported the causes of being
mechanically ventilated: CHF (16%), CAP (16%), COPD
(14%), and sepsis (10%) .
Difficult diagnosis of ARF in the elderly
was 86%for pneumonia,75%for PE,and71%for CHF .
In this study, the variables associated to a missed diagnosis
were a final diagnosis of CHF, CAP or PE, highlighting the
diagnosis of CAP was delayed for more than 72 h in 62% of
patients . The association of dyspnea, cough, and fever,
at admission was very common (45%) [9, 14]. Atypical signs
and confusing [15, 16, 17]. Unfortunately, an inappropriate
diagnosis is associatedwith an increasedmortality (Figure 1a
and b) [3, 18]. The difficulties of diagnosing CHF and
PE [19, 20, 21, 22, 23, 24] are reported in Appendix 1 and
Appendix 2 in the supplementary data on the journal’s web-
Appendix 4 in the supplementary data on the journal’s
The mortality rate associated with ARF in the elderly varies
according to the etiology. In a study, the crude mortality
of CAP requiring hospitalisation was 26%, and age by itself
was not a significant factor related to prognosis . CHF
has an in-hospital mortality, ranging from 13 to 29%, with
a rate of early re-hospitalisation from 29 to 47% within
3–6 months of the initial discharge, and a 1 year survival of
50% [3, 16, 25, 26]. In the EPIDASA study,29% of patients
were admitted to an ICU, and 16% died in hospital. The
five variables associated to death were: inappropriate initial
treatment, hypercapnia >45 mmHg, creatinine clearance
<50 ml/min, elevated B-type natriuretic peptides (BNP
and NT-proBNP), and clinical signs of ARF. Age was not
significantly associated with mortality.
Prognosis of elderly admitted in an ICU
Age is included in several scores of severity such as the
APACHE II, Fine’s score for CAP , and Aujesky’s
score for PE [2, 28]. However, the large majority of the
studies indicate that acute physiology disturbances and
diagnosis have larger relative contributions to prognosis
than age . Kaarlola et al. reported that the cumulative 3-
year mortality rate among the elderly patientswas lower than
that among the controls (40% versus 57%). However, 88%
of the elderly survivors assessed their present health state as
The decision to admit a patient to the ICU from the ED
is challenging, as physicians must decide in a short time.
When a patient potentially requiring ICU care is admitted to
the ED, emergency physicians take the first decision as to
are involved only if an ICU admission is requested for
the patient. Age over 85 years seems to be an independent
predictor of ICU refusal . Actually, the decision to admit
Number of Days
Percent of patients
Percent of patients
Number of Days
Figure 1. (a) Effects of an appropriate (black bars) or inappropriate (white bars) initial diagnosis in the emergency department on
prognosis (used with permission from Ray P. ). (b) Effects of an appropriate (black bars) or inappropriate (white bars) initial
treatments in the emergency department on prognosis (used with permission from Ray P. ).
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S. Delerme and P. Ray
Medical History, physical findings,
CXR, ABG, EKG
Previous cardiac or lung disease
Respiratory disorders ?
CHF very likely2
Nitrate IV bolus, diuretics,
ACEi, NIV, Doppler-EC
100 < BNP < 500
BNP < 100 pg/mLBNP > 500 pg/mL
CHF, CAP, ACS …
CT chest with parenchymal
windows, then protocole PE
or lung ultrasonography
Figure 2. Diagnostic strategy based on B-type natriuretic peptide levels in elderly patients admitted for ARF in the emergency
department.1In the grey zone (BNP between 100 and 500 pg/ml), which represents less than a quarter of patients, further
investigations are needed, and ER physicians should consider massive PE, CHE, severe exacerbation of COPD or severe
pneumonia as possible diagnoses.2Physicians should keep in mind that half of elderly patients with ARF has more than one
diagnosis, i.e. a BNP greater than 500 pg/ml strongly suggests CHF, but other diagnosis that could have precipitated CHF.
CXR: chest X-ray; EKG: electrocardiogram; ABG: arterial blood gas analysis; CHF: congestive heart failure; ACS: acute coronary
syndrome; CT: computed tomography; IV: intravenous; NIV: non-invasive ventilation including continuous positive airway
pressure; ACEi: angiotensin converting enzyme inhibitor; EC: echocardiography.
an elderly patient to an ICU should be based on the patients’
and the patient’s preferences .
How could we improve outcomes of ARF
in elderly patients?
Studies suggested that an inappropriate diagnosis and
treatment were associated with an increased mortality rate
[Figure 1(b)] [3, 18]. Usual tools used to differentiate CHF
from respiratory disorders are not very accurate, even the
PE . Thus valid diagnostic tools for differentiating CHF
from other etiologies of ARF could aid clinicians.
Usefulness of transthoracic echocardiography
Echocardiography (EC) should be encouraged because
the diagnosis of systolic CHF can be easily confirmed
by the emergency physician [33, 34]. However non-systolic
CHF is more difficult to evaluate by EC, and needs
Doppler and myocardial tissue imaging (see Appendix
1 in the supplementary data on the journal’s website
Role of B-type natriuretic peptides
BNP is a polypeptide, released by ventricular myocytes
directly proportional to wall tension, for lowering renin-
angiotensin-aldosterone activation. In the blood, the
cleavage of a precursor protein produces BNP and the
biologically inactive NT-proBNP. For diagnosing CHF,
both BNP and NT-proBNP have similar accuracy [36, 37]
(see Appendix 1 in the supplementary data on the journal’s
website http://www.ageing.oxfordjournals.org). However,
threshold values are higher than in middle-aged population.
A study demonstrated that the use of BNP in patients
>70 years early in the ED reduced the time to discharge,
total treatment cost, and 30-day mortality. Figure 2 shows a
for ARF in the ED [38, 39]
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ARF in the elderly: diagnosis and prognosis
Diagnosing CAP is difficult and urgent because it requires
prompt antibiotics . Thus, biological markers such as C-
to suggest bacterial infection . PCT seems to be more
value . Several studies suggested that, in a middle-aged
guidance of antibiotherapy reduced antibiotic use without
adverse effect . However, in elderly patients Strucker
et al. have found that it had a low sensitivity (24%) for
Potential usefulness of thoracic imaging
When PE is suspected, throcacic computed tomography
(CT) isnow oneofthe first lineinvestigations(seeAppendix
2 in the supplementary data on the journal’s website
http://www.ageing.oxfordjournals.org, Figure 2) . Fur-
thermore, thoracic CT is useful in determining alternate
diagnoses (pneumonia or CHF missed on CXR). In case of
unknown ARF, we recommend to begin with parenchymal
by contrast injection to rule in PE if the parenchymal win-
dows do not explain the clinical picture [46, 47]. However,
physicians should be aware of the risks taken in performing
helical CT scan. .
Lung ultrasound could also be useful, but needs further
evaluation [49, 50].
Treatment of ARF
Medical and social aspect
Most emergency physicians do not have the expertise to
comprehensively address the myriad of needs of elderly
patients with complex chronic illnesses (for example, in the
EPIDASA study, 45% of the patients had previous cardiac
disease and 26% chronic respiratory disease ) and daily
treatments (in one study, the average number of drugs taken
may affect the respiratory and cardiac systems (for example,
ß-blockers prescribed for hypertension have an effect on
lung function). A multi-disciplinary care model, involving
emergency physicians, gerontologist physicians, nurses,
clinicial pharmacist, social worker, family doctor should
be encouraged .
Hypoxaemic patients with ARF need oxygen supplemen-
tation as the first stage of treatment. However, studies
suggested that injudicious use of oxygen therapy is asso-
ciated with increased hypercapnia in COPD patients .
Thus, it is important that, emergency physicians aim at pro-
viding an oxygen saturation >90%, and check blood gases
30 min after starting oxygen in COPD patients .
Management of pneumonia in the elderly
Previous studies showed the important role of silent
aspiration and the low prevalence of Legionella sp., Chlamydia
and Mycoplasma pneumoniae in CAP  Streptococcus pneumoniae
is the most common cause of CAP in the elderly.
Conversely, gram-negative bacilli (Klebsiella, Proteus sp,
Escherichia coli, and others) account for half of all the
culture-diagnosed pneumonias in nursing-home acquired
pneumonia. Recommendations for anti-microbial drug
use depend on the suspected specific organism, and
guidelines [54, 55]. The main objective is to start antibiotics
as early as possible since antibiotic administration within
4 h of hospital arrival is associated with a lower 30-day
mortality . Recently, it was suggested that the SOAR
score (based on systolic blood pressure, oxygenation, age
and respiratory rate) was an alternative criteria for a
better identification of severe CAP in advanced age where
both raised urea level above 7 mmol/l and confusion are
Pharmalogical treatment of CHF
and morphine, based on the ‘inappropriate’ concept that
CHF is caused by fluid accumulation rather than fluid
right and left ventricular preload and reducing pulmonary
venous pressure directly) and arteriodilatation (reducing
the afterload mismatch and therefore increasing cardac
index). Cotter et al.  demonstrated that boluses of high-
dose isosorbide dinitrate improved outcome compared to
repeated high-doses furosemide . Sacchetti et al. 
demonstrated that morphine sulfate use in the ED was
intubation, whereas captopril sublingual use was associated
with a decreased ICU admissions, and a decreased need for
endotracheal intubation. Considering the fact that 50% of
the elderly with CHF have preserved systolic function 
and that nearly two thirds present with hypertension, nitrate
should be preferred . Rapid determination of whether
there is a systolic or non-systolic CHF is important because
the etiologies and pharmalogical treatment are different (see
Appendix 1 in the supplementary data on the journal’s
website http://www.ageing.oxfordjournals.org) .
Potential role of non-invasive ventilation by a face
In acute COPD exacerbations, non-invasive positive-
pressure ventilation (NPPV) decreases PaCO2by unloading
the respiratory muscles and supplementing alveolar venti-
lation. Several trials and meta-analysis support the use of
NPPV by reducing ventilator associated pneumonia, intuba-
on NPPV suggest that the response of middle-aged patients
with acidotic COPD exacerbations to NPPV may extend to
the geriatric population. In CHF, NPPV improves oxygena-
by guest on June 1, 2013
S. Delerme and P. Ray
and decrease mortality . One study demonstrated that,
compared to medical treatment, continuous positive air-
way pressure (CPAP) decreased respiratory rate, decreased
PaCO2, and improved oxygenation compared with baseline
in elderly patients with hypoxaemic CHF . However, the
in-hospital mortality (28% versus 30%) was not different.
for CHF .
CHF is the most common cause of ARF in the elderly
but half of the patients had more than two diagnoses.
As inappropriate treatment is associated with increased
morbidity and mortality, accurate diagnostic tools, such
as BNP, should be available in an ED 24 h a day. We
should consider non-invasive ventilation (NIV) in elderly
patients hospitalised with acidotic COPD exacerbations or
CHF who do not improve with medical treatment. ICU
admission decisions should not be based on age alone but
on factors such as the patient’s baselinelevel of function and
co-morbidities, severity of illness, and preferences for life
• A misdiagnosis in the ED is associated with increased
morbidity and mortality.
diagnostic accuracy and outcome.
• NIV should be an option for severe CHF or COPD
The authors would like to thank the physicians and
nursing staff working in the emergency department of Piti´ e-
Salpˆ etri` ere Hospital for their co-operation and support. We
also would like to thank Dr Joanne Ho (Internal Medicine,
Toronto, Canada) for the review of the manuscript.
Conflict of interest
Supplementary data for this article are available online at
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Received 12 April 2007; accepted in revised form 7 November
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