Induction

INDUCTION

  • Elisha Coppens, DNAP, MPharm, CRNA, APRN, CHSE, COI

GOALS OF ANESTHESIA

  • Amnesia: To prevent the patient from retaining memories of the surgery.

  • Analgesia: To provide relief from pain during and after the procedure.

  • Hypnosis: To induce a state of unconsciousness or sleep.

  • Akinesia: To prevent movement or muscle activity during surgery.

INDUCTION WITH ENDOTRACHEAL INTUBATION

  • Appropriate Medications:

    • Fentanyl: 25 - 100 mcg (0.5 - 1 mcg/kg)

    • Propofol: 1 - 2.5 mg/kg

    • Lidocaine: 0.5 - 1.5 mg/kg

    • Neuromuscular Blockers (NMB):

    • Succinylcholine: 0.3 - 1 mg/kg

    • Rocuronium: 0.6 - 1.2 mg/kg

ANESTHESIA TYPES

  • Conscious Sedation: A level of sedation that allows the patient to remain aware and able to respond.

  • Local Infiltration: Injection of anesthetic directly into the tissue.

  • TIVA/MAC: Total Intravenous Anesthesia / Monitored Anesthesia Care.

  • Regional Anesthesia: Targets a specific region of the body.

  • General Anesthesia: Involves loss of consciousness via:

    • IV Anesthetics

    • Inhaled Anesthetics

    • IM Anesthetics: Such as ketamine, brevatol.

INDUCTION TECHNIQUES

  • SAB (Sub-Arachnoid Block)

  • Epidural Anesthesia

  • Peripheral Nerve Blocks (PNB)

  • TAP Block (Transversus Abdominis Plane)

  • Caudal Block

PREOPERATIVE GI MEDICATIONS

  • Patients taking antacid medications (e.g., PPIs and H2RAs) should continue their regimen until surgery.

  • PPIs: More effective when given in two doses:

    • One the evening before surgery

    • Another on the morning of surgery

  • IV Metoclopramide: Helps by increasing lower esophageal sphincter tone, inducing peristalsis, and enhancing stomach emptying, reducing gastric volume and aspiration risk.

PREMEDICATION

  • Administered to relieve anxiety, manage physiological responses to airway management, and optimize stomach content volume and pH.

  • Anxiolytics: Example - Benzodiazepine (e.g., midazolam) up to 1-2 mg IV for stable patients, titrated cautiously, particularly in older adults or with narcotic use to avoid hypotension and loss of airway reflexes.

INDICATIONS FOR INDUCTION

  • Preparation of the operating room and selection of techniques and medications.

  • Gathering additional equipment based on assessment.

  • Confirming readiness for the surgical suite.

OPERATING ROOM PREPARATION

  • Apply monitors and obtain baseline vital signs.

  • Perform a time-out with the surgical team to confirm patient identity, date of birth, surgical site, and side.

PREOPERATIVE CHECKLIST

  • Equipment to ensure:

    • Suction: Ready at all times.

    • Oxygen: Available for pre-oxygenation.

    • Airway management tools: Must be ready for use.

    • Pre-oxygenation: Administer 100% oxygen for 3-5 minutes to achieve optimal oxygenation.

SPECIAL TECHNIQUES & TOOLS

  • Sellick’s Maneuver (Cricoid Pressure): Prevents passive regurgitation and aspiration in an unconscious patient.

    • Positioning: Atlanto-occipital extension with head elevation of 3-7 cm, head of bed elevated 20º.

  • Video Laryngoscopy: Use of equipment like Glidescope or McGrath, or fiberoptic bronchoscopy (FOB).

  • Bougie & Retrograde Intubation: Techniques for difficult airway management.

  • Surgical Airway Techniques: Crico-thyrotomy as an emergency procedure.

    • Indicates when to consider awake fiberoptic intubation, particularly in specific populations like trauma patients, pregnant patients, or those with known difficult intubation histories.

RAPID SEQUENCE INDUCTION (RSI)

  • General Indications:

    • Full stomach conditions: Trauma, suspected difficult intubation, gastrointestinal pathologies (e.g., SBO, gastric outlet syndrome, esophageal stricture), severe GERD, increased abdominal pressure, ascites, pregnancy beyond 20 weeks.

    • Additional considerations: Use 100% O2 for at least 3 minutes on patients at increased risk of aspiration during induction.

POSITIONING FOR INTUBATION

  • Sniffing Position: Aligns oral, pharyngeal, and laryngeal axes for optimal visualization.

    • Variants include:

    • Neutral position

    • Flex neck or elevate occiput for improved alignment.

INHALATION INDUCTION WITH SEVOFLURANE

  • Sevoflurane: Commonly used due to its sweet smell and low tissue and blood solubility. Typical concentration is 4-8% with N2O.

    • N2O (Nitrous Oxide): Benefits from the "second gas effect" that enhances the uptake of other anesthetic gases. Avoid in specific scenarios: bowel obstruction, middle ear pressure changes, pneumonias, etc.

ORDER OF INDUCTION

  1. Preoperative tasks:

    • Establish IV access, take patient history, and acquire informed consent.

    • Administer anti-anxiety medications as necessary.

    • Consider postoperative nausea and vomiting (PONV) prophylaxis.

  2. Induction Steps:

    • Position the patient on the operating table or stretcher.

    • Apply monitors and check baseline vital signs.

    • Preoxygenate the patient for optimal oxygenation.

    • Administer induction medications (e.g., Lidocaine, Propofol) and verify airway position.

    • Insert and attach additional monitors, including foley catheters, esophageal stethoscopes, and temperature probes.

    • Employ warming devices, as needed, and prepare for surgical incision.

PREOXYGENATION TECHNIQUES

  • Administer 100% oxygen for 3-5 minutes with normal tidal volume breathing, achieving an ET O2 level of > 90%.

  • For patients with oxygenation issues (e.g., obesity, pregnancy) perform pre-oxygenation with head elevated by 15-30 degrees.

STANDARD INTUBATION STEPS

  1. Administer Lidocaine and Propofol.

  2. Check eyelash reflex and train-of-four (TOF).

  3. Administer neuromuscular blocker (rocuronium).

  4. Place tape over eyes.

  5. Mask ventilate for 90 seconds.

  6. Use scissors to open mouth with right hand.

  7. Insert laryngoscope blade with left hand to obtain a view.

  8. Place endotracheal tube (ETT), removing the stylette.

  9. Inflate balloon of ETT.

  10. Cover laryngoscope with an extra glove and set it down.

  11. Attach breathing circuit and close APL to approximately 30 mmHg.

  12. Provide a breath and assess for chest rise and ETCO2.

  13. Listen for lung sounds, readjust as needed.

  14. Taper down gas flows, activate volatile agents, and initiate ventilator settings.

  15. Tape ETT securely.

RAPID SEQUENCE INDUCTION/intubation STEPS

  1. Initiate cricoid pressure.

  2. Administer Lidocaine, Propofol, and Succinylcholine while maintaining mask ventilation.

  3. Watch for fasciculations.

  4. Proceed with the same steps as standard intubation after ensuring proper airway control.