Lecture 9
Monitoring Oxygenation and Ventilation
o Oxygenation: Assessment of ABGs, SpO , SvO /S2vO , a2d clin2cal signs of
hypoxemia such as a change in mental status (e.g., confusion), anxiety, dusky skin,
and dysrhythmias.
o Ventilation: Assessment of PaCO , con2inuous partial pressure of end-tidal CO 2
(PETCO ),2and clinical signs of respiratory distress such as use of accessory muscles,
hyperventilation with circumoral and peripheral numbness and tingling, and
hypoventilation with dusky skin.
Continuous PETCO moni2oring can be used to assess the patency of the
airway and the presence of breathing.
Gradual changes in PETCO valu2s may accompany an increase in CO 2
production (e.g., sepsis) or decrease in CO 2roduction (e.g., hypothermia).
Maintaining Tube Patency
o The patient should be assessed routinely to determine a need for suctioning, but the
patient should not be suctioned routinely.
Indications for suctioning include (1) visible secretions in the ET tube, (2)
sudden onset of respiratory distress, (3) suspected aspiration of secretions, (4)
increase in peak airway pressures, (5) auscultation of adventitious breath
sounds over the trachea and/or bronchi, (6) increase in respiratory rate and/or
sustained coughing, and (7) sudden or gradual decrease in PaO and2or SpO . 2
o The closed-suction technique (CST) uses a suction catheter that is enclosed in a
plastic sleeve connected directly to the patient-ventilator circuit.
With the CST, oxygenation and ventilation are maintained during suctioning
and exposure to secretions is reduced.
CST should be considered for patients who require high levels of positive end-
expiratory pressure (PEEP), who have bloody or infected pulmonary
secretions, who require frequent suctioning, and who experience clinical
instability with the open-suction technique (OST).
o Potential complications associated with suctioning include hypoxemia,
bronchospasm, increased intracranial pressure, dysrhythmias, hyper/hypotension,
mucosal damage, pulmonary bleeding, and infection.
Assess patient before, during, and after the suctioning procedure.
If the patient does not tolerate suctioning (e.g., decreased SpO 2 development
of dysrhythmias), stop procedure and manually hyperventilate patient with
100% oxygen or if performing CST, hyperoxygenate until equilibration
occurs.
Hypoxemia is prevented by hyperoxygenating the patient before and after
each suctioning pass and limiting each suctioning pass to 10 seconds or less.
If SvO 2ScvO a2d/or SpO are 2sed, trends should be assessed throughout the
suctioning procedure.
Tracheal mucosal damage may occur because of excessive suction pressures
(>120 mm Hg), overly vigorous catheter insertion, and the characteristics of
the suction catheter itself. Secretions may be thick and difficult to suction because of inadequate
hydration, inadequate humidification, infection, or inaccessibility of the left
mainstem bronchus or lower airways.
Adequately hydrating the patient (e.g., oral or intravenous fluids)
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