Page 483 - Clinical Application of Mechanical Ventilation

Pharmacotherapy for Mechanical Ventilation 449

Propofol

Propofol (Diprivan) is an intravenous (IV) drug administered together with other
propofol (Diprivan): An
intravenous drug that provides a anesthetics to produce and maintain anesthesia. A hypnotic effect is produced within
spectrum of CNS effects ranging 40 sec after a rapid IV bolus administration (1 to 2.5 mg/kg). The maintenance dose
from light sedation to deep
general anesthesia. is 0.05 to 0.2 mg/kg/min by IV infusion (Reiss et al., 2006). Propofol is used to pro-
vide sedation in ventilator patients and for induction and maintenance of anesthesia.
Mechanism of Action. Propofol appears to enhance GABA-activated chloride ion
channel function (for a complete discussion, see Sedatives and Antianxiety Agents
[Benzodiazepines] in this chapter) (Fragen et al., 1992). The mechanism of action
may involve a separate receptor recognition site or may involve a different mecha-
nism from that previously discussed for barbiturates and benzodiazepines.

Adverse Effects. Adverse reactions reported with propofol use include apnea, brady-
cardia, laryngospasm, bronchospasm, coughing, dyspnea, hypotension, and burning
or pain at the site of infusion. Discoloration of the urine to green or red-brown may
occur due to liver metabolites of propofol (Mirenda et al., 1995; Reiss et al., 2006).
Propofol is highly fat-soluble and is formulated in an oil-in-water vehicle. The soy-
Propofol is formulated in bean oil in this vehicle could contribute a significant amount of calories from fat.
an oil-in-water vehicle and it
could contribute a significant Therefore, other sources of dietary intake must be adjusted to compensate for the
amount of calories from fat. amount of fat infused. In addition, patients receiving propofol should be monitored
for elevations in serum triglycerides. Because fat emulsion provides an excellent me-
dium for microbial growth, and propofol contains no preservatives, strict aseptic ad-
ministration techniques are important to prevent iatrogenic sepsis.
Since fat emulsion
provides an excellent medium Clinical Considerations. Propofol has analgesic properties but only at doses used for
for microbial growth, strict
aseptic techniques are general anesthesia, therefore attention must be paid to providing adequate analgesia
essential. in patients requiring pain relief. When opioid analgesics are used in combination
with propofol, additive hypotension may occur.
Since propofol does not promote salivation or vomiting, its use can be an advan-
tage for intubated patients (Reiss et al., 2006). The rapid onset and offset of seda-
tion may be a disadvantage if patients are allowed to awaken abruptly in pain or to
Propofol has analgesic
properties but only at doses great environmental disorientation (Levine, 1994). This problem can be avoided by
used for general anesthesia. decreasing the infusion rate so that the patient awakens slowly.
Additional analgesics may be
needed for pain control when As discussed previously in the benzodiazepine section, monitoring the level of
used at sedative doses. sedation is important to avoid over- or under-sedation. The Ramsay Scale (refer to
Sedatives and Antianxiety Agents [Benzodiazepines] in this chapter for a discussion)
or computer-assisted cerebral function monitoring can be used to determine the
patient’s level of sedation. The latter notes changes in brain function on a real-time
basis and, with adequate training, the changes may be interpreted by caregivers.

Haloperidol

haloperidol (Haldol): A drug for Pharmacotherapy for sedation and anxiolysis may in some patients paradoxically
the control of delirium in mechani- cause delirium. Haloperidol (Haldol) may be effective in these situations where
cally ventilated patients.
control of delirium in mechanically ventilated patients is desirable. Delirium may be

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