Chapter 10-Postintubation management

Following the placement of the endotracheal tube (ETT) and confirmation of its correct tracheal location, the immediate priority is airway management.
Although intubation alleviates significant stress, various airway-related concerns persist post-intubation.
This chapter reviews key aspects of management after tracheal intubation.

Initial Confirmation: Confirm correct tracheal placement via objective means:
- Visualization of the ETT passing through the vocal cords.
- Detection of end-tidal CO2 (ETCO2).
- Use of an esophageal detector device.
Considerations:
- In well preoxygenated patients, oxygen desaturation may be a late event following esophageal intubation.
ETT Positioning: Ensure the ETT tip is above the carina to avoid endobronchial intubation (common problem).
- Endobronchial intubation can lead to severe complications: hypoxia, barotrauma, and direct lower airway trauma.
- Use numeric markings on the ETT for depth confirmation (20-22 cm at the teeth in adults).
- Auscultation is essential post-intubation, but not relied upon solely; unequal breath sounds point to possible endobronchial intubation or pneumothorax.
Chest X-ray: Used to confirm ETT positioning and identify complications.

Once ETT placement is confirmed, secure the tube to prevent displacement.
Methods:
- Adhesive Tape: Unreliable due to potential interference from body substances.
- Cotton Twill Tape: Effective, but ensure it’s not too tight, especially in patients with head injuries.
- Single-use ETT Clamp Devices: Safe and practical, often serving as bite blocks.

Begin manual ventilation to assess lung compliance; be cautious of not hyperventilating the patient, particularly with conditions like asthma or COPD.
Self-inflating Resuscitators: Generally provide 1600 mL volume; to avoid excess, use a gentle compression technique.
Initial Settings:
- FiO2: Start at 100% and titrate down based on monitoring (pulse oximetry or arterial blood gas).
- Frequent suctioning may be required post-intubation to maintain airway patency.

Blood pressure should be checked immediately and monitored every 1-3 minutes for the first 15 minutes post-intubation until stable.
Hypotension: Common after intubation, particularly if rapid sequence intubation (RSI) was used.
- Mechanisms contributing to hypotension:
- Negative inotropic effects of induction agents.
- Impeded venous return due to positive pressure ventilation.
- Alleviation of catecholamine excess due to reduced work of breathing post-intubation.
- Consider pneumothorax in at-risk patients (e.g., trauma, rib fractures).

Address volume deficits and optimize drug dosing for induction.
- Notably, urgent intubations often occur without full fluid resuscitation.
Hypotension typically lasts 10-15 minutes without significant consequences, but it can be critical in certain patient populations:
- Head injuries and serious vascular diseases.
Fluid Administration: Start with 10-20 mL/kg crystalloid bolus.
Vasopressors: Use short-acting options such as:
- Ephedrine: 5-10 mg IV.
- Phenylephrine: 40-100 µg IV.
Prolonged Hypotension: Reflects underlying disease; manage accordingly.

Hypertension and tachycardia may occur post-intubation, often self-limited.
Treatment is indicated for patients with:
- Aneurysms or significant coronary artery disease.
- Awareness during paralysis may require increased sedative doses.

Postintubation sedation is vital; it should commence even before the patient regains consciousness following RSI.
Sedation Considerations:
- Clinician comfort, patient hemodynamics, and anticipated illness progression.
Sedative Examples:
- Midazolam: 0.025-0.05 mg/kg IV every 30-60 minutes.
- Propofol: 25-100 µg/kg/min infusion; initial bolus may be 0.2-0.6 mg/kg.
Narcotic Analgesics:
- Fentanyl: 0.5-2.0 µg/kg every 20-30 mins.
- Morphine: 0.025-0.1 mg/kg every 20-30 mins.
Muscle Relaxants:
- Used for ongoing muscle relaxation, if necessary:
- Rocuronium: 0.6 mg/kg load, 0.1-0.2 mg/kg every 20-30 mins.
- Vecuronium: 0.1 mg/kg load, 0.01 mg every 30-45 mins.
Monitoring: Ensure continuous monitoring of vital signs, given complexity of sedation in the critically ill patient.

Discussion of mechanical ventilation falls outside this sections primary focus but includes key processes:

Most patients post-RSI require this mode.
Set tidal volume (8-10 cc/kg) and respiratory rate (approximately 10 breaths/min).
Monitoring: Peak airway pressure in normal lungs should be <25 cm H2O.
Causes of increased airway pressure:
- Stiff lungs (e.g., asthma, COPD).
- Parenchymal issues (e.g., pneumo- or hemothorax).
- Ventilator circuit issues (kinking, ETT position).

Requires respiratory drive from the patient.
Simplified example: Pressure support ventilation (PSV), typically set at 5-10 cm H2O.
Effective for patients overcoming ETT resistance, aiding in weaning process.

Utilized to enhance oxygenation and functional residual capacity (FRC).
Caution: May lower blood pressure and impair cerebral venous drainage, especially in head-injured patients.

Oxygenation: Monitor via pulse oximetry, adjusting FiO2 to maintain adequate SaO2 levels.
Recognize that stable patients can rely on ETCO2 measurements for tidal volume management, but major hemodynamic changes necessitate arterial blood gas analysis.

Intubation marks a step in airway management but does not signal its end; vigilance in the post-intubation phase is critical.
- Common occurrences: hypotension (often managed with sedation or fluid resuscitation) and accidental extubation risk must be factored into post-intubation protocols.

A comprehensive list of studies and articles was provided to support the evidence discussed, emphasizing the importance of ongoing research in airway management practices.