Fellowship of Pediatric Pulmonology
Respiratory distress is a clinical
inability of the lungs to provide sufficient
oxygen (hypoxic respiratory failure) or
remove carbon dioxide (ventilatory failure)
to meet metabolic demands.
Pao2 < 60 torr with breathing of room air
Paco2 > 50 torr resulting in acidosis,
the patient's general state, respiratory
effort, and potential for impending
exhaustion are more important indicators
than blood gas values.
Respiratory distress can occur in
patients without respiratory disease,
respiratory failure can occur in patients
without respiratory distress.
Arterial gas composition
depends on :
the gas composition of the atmosphere
the effectiveness of alveolar ventilation
pulmonary capillary perfusion
diffusion across the alveolar capillary
The Paco2 increases in proportion to a
decrease in ventilation.
Pao2 falls approximately the same
amount as the Paco2 increases.
The relationship between oxygenation and
hypoventilation is complicated by the shape
of the Hb-dissociation curve
Because of the dissociation curve, a patient
who exhibits alarming CO2 retention might
have a near normal oxygen saturation.
When Paco2 increases from 40 to 70 mm Hg, a dangerous level
of hypoventilation, might have a Pao2 that has decreased from
100 to 60 mm Hg and, therefore, maintain an oxygen saturation
1. PO2 100 mm Hg= SpO2 of 97%
2. PO2 60mm Hg= SpO2 of90%
oximetry is not a sensitive indicator of the
adequacy of ventilation.
This is particularly true when a patient is receiving oxygen.
Diseases of the lung or airways affect gas
exchange most often by disrupting the normal
matching of V/Q or by causing a shunt.
usually can maintain a normal Paco2 as lung
disease worsens simply by breathing more.
hypoxemia is the hallmark of lung disease
diffusion defects manifest as hypoxemia
rather than hypercarbia.
pneumonia, ARDS, Scleroderma, Pulmonar
Monitoring a Child in
Respiratory Distress and
Clinical observation is the most
important component of monitoring.
ABG & Oximetry
ABG /CBG/ VBG
- Oximetry provides an invaluable and usually
accurate measurement of oxygenation.
- important to recognize its technical limitations
Dark skin pigment
Anemia Causes inadequate signal
Bright external light
— Severe right heart failure
— Tricuspid regurgitation
— Tourniquet or blood pressure
cuff above site
Results in low reading
Unreliable reading (tends to read
80% to 85% saturation regardless of
— SS hemoglobin Saturation
accurate, but hemoglobin
dissociation curve shifted to right
Spuriously high saturation readings
most common cause of cardiac arrest in children.
When presented with a child who has:
a decreased level of consciousness,
slow/shallow breathing, or increased
respiratory drive, the possibility of
ARF should be considered
to assure adequate gas exchange and
circulation (the ABCs).
Oxygen Administration to maintain ….
If Ventilation is or appears to be inadequate …..