Pharmacologic Adjuncts to Airway Management and Ventilation

EMS 352 DR AQEELA BANO

Pharmacologic Adjuncts to Airway Management and Ventilation

• Decrease the discomfort of intubation• Decrease the incidence of complications • Make aggressive airway management possible

for patients who are unable to cooperate

Sedation in Emergency Intubation

• Reduces anxiety, induces amnesia, decreases gag reflex

• Undersedation:– Inadequate cooperation– Complications of gagging – Incomplete amnesia

Sedation in Emergency Intubation

• Oversedation:– Uncontrolled general anesthesia– Loss of protective airway reflexes– Respiratory depression– Complete airway collapse– Hypotension

Sedation in Emergency Intubation

• Desired level of sedation dictates dose

• Two major classes:– Analgesics:

decrease perception of pain

– Sedative-hypnotics: induce sleep, decrease anxiety

Butyrophenones

• Potent, effective sedatives – Haloperidol and droperidol relieve anxiety.

• Do not produce apnea • Little effect on cardiovascular system• Not recommended to induce anesthesia

Benzodiazepines

• Sedative-hypnotic drugs• Diazepam and midazolam– Provide muscle relaxation, mild sedation– Used as anxiolytic and antiseizure medications– Provide anterograde amnesia

Benzodiazepines

• Neuromuscular blockers preferred for muscle relaxation

• Potential side effects:– Respiratory depression– Slight hypotension

• Flumazenil: benzodiazepine antagonist

Barbituates• Sedative-hypnotic

medications• Thiopental

– Short acting– Rapid onset

• Methohexital– Ultra-short acting– Twice as potent

• Can cause – Respiratory depression– Drop in blood pressure

• Potentially irreversible in hypovolemic patients

Opioids/Narcotics

• Potent analgesics with sedative properties• Two most common: fentanyl, alfentanil• Can cause respiratory and central nervous

system depression • Naloxone: narcotic antagonist

Nonnarcotic/Nonbarbituate

• Etomidate – Hypnotic-sedative drug– Often used in induction of general anesthesia– Fast-acting, short duration– Little effect on pulse rate, blood pressure,

intracranial pressure (ICP)

Nonnarcotic/Nonbarbituate

• Etomidate (cont’d)– No histamine release and bronchoconstriction– High incidence of myoclonic muscle movement– Useful induction agent in patients with:• Coronary artery disease• Increased ICP• Borderline hypotension/hypovolemia

Neuromuscular Blockade in Emergency Intubation

• Cerebral hypoxia can make patients combative and uncooperative.– Requires aggressive oxygenation, ventilation– Neuromuscular blocking agents are safer.

Neuromuscular Blocking Agents

• Affect every skeletal muscle • Within about 1 minute, patient is paralyzed• Must be able to secure the airway• No effect on LOC.

Pharmacology of Neuromuscular Blocking Agents

• Skeletal muscles are voluntary.– Impulse to contract reaches a motor nerve– Acetylcholine (Ach) is released.• Diffuses, occupies receptor sites• Triggers changes in electrical properties of the muscle

fiber (depolarization)

Pharmacology of Neuromuscular Blocking Agents

• Paralytic medications– Relax the muscle by

impeding the action of Ach

– Two categories: depolarizing and nondepolarizing

Depolarizing Neuromuscular Blocking Agent

• Competitively binds with ACh receptor sites– Not affected as quickly by acetylcholinesterase

• Succinylcholine chloride is the only agent.– Fasciculations can be observed during its

administration.

Depolarizing Neuromuscular Blocking Agent

• Very rapid onset of total paralysis• Short duration of action • Use with caution in patients with burns, crush

injuries, and blunt trauma• Can cause bradycardia

Nondepolarizing Neuromuscular Blocking Agents

• Bind to ACh receptor sites but do not cause depolarization of the muscle fiber.

• Prevent fasciculations before a depolarizing paralytic

Nondepolarizing Neuromuscular Blocking Agents

• Most commonly used– Vecuronium bromide (Norcuron)– Pancuronium bromide (Pavulon)– Rocuronium bromide (Zemuron)

• Do not give before the airway is secured.

Rapid-Sequence Intubation (RSI)

• Safe, smooth, rapid sedation and paralysis followed immediately by intubation

• Generally used for patients who are unable to cooperate

Preparation of the Patient and Equipment

• Explain procedure, reassure the patient• Apply a cardiac monitor and pulse oximeter.• Check, prepare, assemble equipment– Have suction available

Preoxygenation

• Adequately preoxygenate all patients.– If the patient is breathing spontaneously and has

adequate tidal volume: • Apply high-flow oxygen via nonrebreathing mask.

– If patient is hypoventilating: • Assist ventilations with a bag-mask device and high-

flow oxygen.

Premedication

• Stimulation of the glottis with intubation can cause dysrhythmias and increase ICP.

• If your initial paralytic is succinylcholine, administer nondepolarizing paralytic.

• Atropine sulfate should be administered to decrease potential for bradycardia.

Sedation and Paralysis

• As soon as patient is sedated, administer paralytic agent– Onset should be complete within 2 minutes.– Signs of adequate paralysis include:• Apnea• Laxity of the mandible• Loss of the eyelash reflex

Intubation

• Intubate trachea as carefully as possible.– If you cannot intubate within 30 seconds, ventilate

for 30–60 seconds before trying again.• If ventilating with a bag-mask device, do so slowly.

Intubation

• Once tube is in the trachea:– Inflate cuff.– Remove stylet.– Verify position of the ET tube.– Secure the tube.– Continue ventilations.

Intubation

• Intubate trachea as carefully as possible.– If you cannot intubate within 30 seconds, ventilate

for 30–60 seconds before trying again.• If ventilating with a bag-mask device, do so slowly.

Intubation

• Once tube is in the trachea:– Inflate cuff.– Remove stylet.– Verify position of the ET tube.– Secure the tube.– Continue ventilations.

Maintenance of Paralysis and Sedation

• Additional paralytic administration may be necessary after intubation.– If you administered succinylcholine, administer a

nondepolarizing agent to maintain paralysis.– If you administered a long-acting paralytic,

additional dosing is usually not necessary.

Maintenance of Paralysis and Sedation

• Modification for unstable patients– If oxygen saturation

drops, ventilate slowly.

– If patient is hemodynamically unstable, judge whether sedation is appropriate.

Maintenance of Paralysis and Sedation

• Additional paralytic administration may be necessary after intubation.– If you administered succinylcholine, administer a

nondepolarizing agent to maintain paralysis.– If you administered a long-acting paralytic,

additional dosing is usually not necessary.