Pulmonary

​

Indications for Intubation

Respiratory Failure (intrinsic and / or extrinsic)

Inability to protect airway (e.g. neurologic decline, excessive secretions)

Loss of airway secondary to anatomy (injury and / or edema)

When considering a patient for intubation and mechanical ventilation, Ask questions directed by the “A.B.G.‘s“

 

A = Airway

1. Is the patient’s airway patent? 

2. Can the patient protect their airway from a neurologic standpoint?

B = Breathing

1. Can they generate spontaneous breaths?

2. Are they strong enough to maintain a respiratory rate and tidal volume to support Oxygen and CO2 exchange necessary for aerobic metabolism?

G = Gas Exchange

1. Can they maintain a ventilation / perfusion ratio that supports oxygenation and prevents hypercapnea?

 

Once patient is safely intubated or has a secure surgical airway: The ventilator should be set based on underlying pathophysiology:

1. Respiratory Failure

   1. Usually will require full positive pressure breathing support, the specific modality is dictated by pathophysiology. Goal of mode choice is to optimize ventilation and perfusion ratio (perfect = 1).

• Inability to protect airway (neurologic)

  • If patient has normal pulmonary gas exchange, and respiratory drive, support breath modes are often all that is needed. Neurologic prognosis will dictate the need for long term airway protection device (i.e. tracheostomy).

  • If ventilation / perfusion is compromised, mandatory breath modes should be used to optimize ratio.

• Loss of airway anatomy

  • If patient has normal pulmonary gas exchange, and respiratory drive, support breath modes are often all that is needed. Prognosis for regaining patent airway anatomy dictates the need for short or long term airway protection device (i.e. tracheostomy).

  • If ventilation / perfusion is compromised, mandatory breath modes should be used to optimize V/Q ratio.

 

 

 

 

 

 

Definition of Modes

I. Mandatory breath modes

 

A. Volume ventilation (VV): a preset volume is delivered. VV is used in either assist/control (AC), where every breath receives minimally the set volume; or SIMV, where the minimum set volume is delivered at a rate based on the breath rate set for mandatory breaths (SIMV rate).

​

B. Pressure ventilation (PV) or pressure control ventilation (PCV): a preset pressure is delivered. PV (PCV) is used in either assist/control (AC), where every breath receives set pressure; or SIMV, where a set pressure is delivered at a rate based on the breath rate set for mandatory breaths (SIMV rate). The risk of pressure mode is that low tidal volumes can occur when any even increases intra-thoracic pressures. A low tidal volume alarm must be set when using pressure mode ventilation.
 

C. PRVC (pressure regulated volume control): pressure ventilation is delivered such that the pressure is automatically adjusted by the ventilator to provide a set tidal volume. This mode is used in either assist/control, where every breath receives minimally the set volume; or SIMV, where the minimum set volume is delivered at a rate based on the breath rate set for mandatory breaths (SIMV rate)

​

D. APRV (airway pressure release ventilation): pressure ventilation that supports spontaneous breaths - in which, the following parameters are set: P-high (high pressure), P-low (low pressure or low PEEP/CPAP), T-high (time during which high pressure is delivered; T-low (time during which low pressure.) Currently APRV is considered a ‘rescue therapy’  – which means it is resource sometimes when the patient has significant pulmonary failure that is not responding to traditional adjuncts. Use of this modality is a team effort and requires a discussion with the ICU attending, respiratory therapy and beside nursing, prior to initiation.

​

Definitions continued - Support breath modes

​

A. Pressure support (PS): a patient-triggered, pressure targeted, flow-cycled mode. This can be a stand-alone breath type in patients who have an intact respiratory drive, or it can be used in combination with mandatory breath types (e.g. AC, SIMV)

​

B. Volume support (VS): a patient-triggered, volume targeted, flow-cycled mode that guarantees a set volume delivery. This can be a stand-alone breath type in patients who have an intact respiratory drive, or it can be used in combination with mandatory breath types. (e.g. AC, SIMV)

​

C. Spontaneous/CPAP: Spontaneous breathing through the ventilator, which allows for monitoring and alarms and also allows for adjustment of the baseline to a continuous positive airway pressure value. This breath type provides only pressure or flow assist to the patient. It can be used alone in patients with adequate respiratory drive and ventilation capabilities or in combination with mandatory breath types (SIMV).

​

Suggestions for Use of Modes

​

1. The selection of the ventilation mode should take into consideration the familiarity of the staff with the mode. 


2. The specific goal for using ventilation should be established for each patient.

   1. In the initial phases of acute respiratory failure, near total ventilator support is recommended. 


   1. As the patient’s condition improves, methods of ventilation (support breath modes) that allow some amount of spontaneous ventilatory activity can be used in lieu of total support. 


 

 

Adult Respiratory Ventilator Recommendations

I. Adult Invasive Ventilation - Initial Parameters and Goals

A. Volume-Ventilation may be used for the majority of patients, but pressure- ventilation (PV or PRVC) should be considered if peak pressures rise over 40 cm H2O or plateau pressures rise >30 cm H2O.

B. Tidal Volume: 6 to 8 cc/Kg of ideal body weight (IBW), while maintaining plateau pressure < 30 cm H2O and delta P < 20 cm H2O.

C. FiO2: Initial setting of 0.6 to 0.9 until results from arterial blood gases (ABG) can be obtained and the setting adjusted.

​

1. Initial ABG should be obtained 15-45 minutes from start of ventilation 


2. Pulse oximetry should be correlated with initial ABG and the patient and subsequently monitored with continuous pulse oximetry to maintain SpO2 at or above patient’s normal or >90% SpO2 (Oxygen saturation by pulse oximetry).

3.  PEEP 5 to 15 cm H2O. Set initial PEEP at 5 cm H2O, unless otherwise indicated. Higher PEEPs may be required with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS).
    

D. Pressure Support (PS): 5 to 20 cm H2O. Maintain Pplateau <30 cm H2O and delta P < 20 cm H2O. PS should be adjusted to reduce work of breathing and patient fatigue and support effective ventilation.

​

G. Begin with I:E ration of 1:3   The I:E ratio should be optimized along with total cycle time (TCT) to provide optimum mean airway pressure, lung filling, lung emptying (minimizing air-trapping/Auto-PEEP), patient/ventilator synchrony.

​

II. Ventilator Adjustments Based on Patient Assessment

1. Initial assessment will be performed within 15-45 minutes from start of ventilation. 


2. Assessment will include evaluation of the patient’s general appearance, blood pressure, heart rate, breath sounds, ventilating pressures and volumes and arterial blood gases (ABG).

​

C. Ventilator synchrony

“Dysynchrony” (aka ‘fighting the ventilator’) is a phenomenon that occurs when the inspiratory breath is resisted by the patient. Dysynchrony with the ventilator can be affected by several factors:

1. Anxiety

2. Pain

3. Chest wall rigidity

4. Positioning

 

Although a cornerstone of ventilator synchronization depends on adequate sedation and analgesia, ventilator mode adjustment can optimize patient comfort while on positive pressure ventilation.  

Ventilator Weaning

​

Daily spontaneous breathing trials: All intubated patients who are not in critical condition, should be considered for a daily spontaneous breathing trial. If:

1. SpO2 > 90%

2. PEEP < 8 cm H20

3. FiO2 < 50%

4. Minute Ventilation < 12 L/min

5. Hemodynamically stable

   1. HR > 50 and < 120 bpm

   1. SBP > 90 and < 180 mm Hg

6. Patient initiates spontaneous inspiratory efforts

7. Patient is able to any of the follow simple commands

   1. Opens eyes, Coughs, lifts head off pillow

​

If the patient tolerates spontaneous breathing for 2 hours, Assess the following:

1) Rapid Shallow Breathing Index (RSBI < 105 is preferred)

2) Cuff leak test (consistent air movement past ETT with balloon cuff deflated)

3) Negative inspiratory force (more negative than – 25 cm H2O pressure)

​

* Intubated patients represent an extremely heterogenous group in terms of physiology. None of these numbers in isolation yields an absolute contraindication to a trial of extubation. Assessment of the overall clinical picture should accompany the weaning parameters listed herein.

 

Assessing for extubation

Before deciding to extubate, ask: “Will the patient S.O.A.R.?”

S) Secretions: how many times is suctioning needed per shift. Are secretions thick and copious or thin and manageable? How strong is the patient’s cough?

O) Oxygenation: Is the patient oxygenating adequately on 40% FiO2 or less? Is SpO2 at least 90%?

A) Airway: Is the patient’s airway anatomically patent with the ETT cuff deflated? Is the patient neurologically responsive enough to protect their airway?

R) Respiratory Drive: On spontaneous breathing mode, is the patient able to maintain CO2 Clearance?

 

 

EXTUBATION

Once a patient is assessed to be ready for extubation, the airway risk should be reassessed.

Was the initial intubation difficult? (review intubation note in EMR)

Does the patient’s anatomy or body habitus suggest potentially difficult intubation?

1. Morbid Obesity

2. Short Neck

3. Immobile neck

4. Anterior Mandibular Space < 6 cm

5. Size of Tongue

6. Facial Fractures (Wired Mandible, Facial / oropharyngeal edema)

7. Previous failed intubations

8. History of tracheotomy / tracheostomy

 

 

If the patient is deemed a high-risk airway. Have anesthesia present at time of extubation, notify them in advance that the patient is a high-risk airway and request they bring their difficult airway equipment.

For all extubations:

1. Have re-intubation tray at bedside.

2. Have a surgical attending present.

3. Stop all continuous gtt sedation and opiates post extubation.  Consider replacing analgesic gtt with PCA if unable to take p.o.

4. Consider swallow study if patient has been intubated for more than 5 days or if neurologically compromised

5. Monitor patient closely in ICU for at least 4 hours after extubation prior to any disposition elsewhere.

6. Document extubation event with an “extubation note in EPIC”. This should describe 1) status of patient prior to extubation and parameters that deemed pt. a candidate for extubation. The key points of the extubation event, AND the patient’s respiratory status immediately after extubation.  After 15 – 30 minutes the patient should be re-assessed and an addendum to the extubation note should be added to document short term success with extubation.