Presentation
Different settings to consider
Monitoring of the patient
Different type of patientCOPD, AsthmaARDS
Trouble shooting
Ventilator settings
1. Ventilator mode
2. Respiratory rate
3. Tidal volume or pressure settings
4. Inspiratory flow
5. I:E ratio
6. PEEP
7. FiO2
8. Inspiratory trigger
PSV(pressure support ventilation)
Spontaneous inspiratory efforts trigger the ventilator to provide a variable flow of gas in order to attain a preset airway pressure.
Can be used in adjunct with SIMV.
Tidal Volume or Pressure setting
Maximum volume/pressure to achieve good ventilation and oxygenation without producing alveolar overdistention
Max cc/kg? = 10 cc/kg
Some clinical exceptions
Inspiratory flow
Varies with the Vt, I:E and RR
Normally about 60 l/min
Can be majored to 100- 120 l/min
FIO2
The usual goal is to use the minimum Fio2 required to have a PaO2 > 60mmhg or a sat >90%
Start at 100%
Oxygen toxicity normally with Fio2 >40%
Positive End-expiratory Pressure (PEEP)
What is PEEP?
What is the goal of PEEP?
Improve oxygenation
Diminish the work of breathing
Different potential effects
PEEP
What are the secondary effects of PEEP? Barotrauma Diminish cardiac output
Regional hypoperfusion NaCl retention Augmentation of I.C.P.? Paradoxal hypoxemia
PEEP
Contraindication:No absolute CI
BarotraumaAirway traumaHemodynamic instability I.C.P.?Bronchospasm?
Look at your patient
Question your pt
Examine your pt
Monitor your pt
Look at the synchronicity of your pt breathing
Compliance pressure (Pplat)
Represent the static end inspiratory recoil pressure of the respiratory system, lung and chest wall respectively
Measures the static compliance or elastance
PplatMeasured by occluding the ventilator 3-5 sec at the end of inspiration
Should not exceed 30 cmH2O
Peak Pressure (Ppeak)
Ppeak = Pplat + Pres
Where Pres reflects the resistive element of the respiratory system (ET tube and airway)
Auto-PEEP or Intrinsic PEEP
What is Auto-PEEP?
Normally, at end expiration, the lung volume is equal to the FRC
When PEEPi occurs, the lung volume at end expiration is greater then the FRC
Auto-PEEP or Intrinsic PEEP
Why does hyperinflation occur?
Airflow limitation because of dynamic collapse
No time to expire all the lung volume (high RR or Vt)
Expiratory muscle activityLesions that increase expiratory resistance
Auto-PEEP or Intrinsic PEEP
Auto-PEEP is measured in a relaxed pt with an end-expiratory hold maneuver on a mechanical ventilator immediately before the onset of the next breath
Auto-PEEP or Intrinsic PEEP
Adverse effects:
Predisposes to barotrauma Predisposes hemodynamic compromises Diminishes the efficiency of the force
generated by respiratory muscles Augments the work of breathing Augments the effort to trigger the ventilator
COPD and Asthma
Goals:
Diminish dynamic hyperinflationDiminish work of breathingControlled hypoventilation
(permissive hypercapnia)
Diminish DHI
How?Diminish minute ventilation
Low Vt (6-8 cc/kg)Low RR (8-10 b/min)Maximize expiratory time
Controlled hypercapnia
How?
Control the ventilation to keep adequate pressures up to a PH > 7.20 and/or a PaCO2 of 80 mmHg
Controlled hypercapnia
CI:Head pathologiesSevere HTNSevere metabolic acidosisHypovolemiaSevere refractory hypoxiaSevere pulmonary HTNCoronary disease
A.R.D.S.
Ventilation with lower tidal volume as compared with traditional volumes for acute lung injury and the ARDS
The Acute Respiratory Distress Syndrome Network
N Engl J Med 2000;342:1301-08
Methods
March 96 – March 9910 university centersInclusion:Diminish PaO2Bilateral infiltrateWedge < 18
ExclusionRandomized
Methods
A/C 28d or weaning2 groups: 1. Traditional Vt (12cc/kg) 2. Low Vt (6cc/kg)
End point: 1. Death 2. Days of spontaneous breathing 3. Days without organ failure or barotrauma
Trouble Shooting
1. Call the I.T., he will take care of it!
2. Where is the staff?
3. I dont know this pt, and run!
4. Ask which pressure is going up
Trouble Shooting
If your Pplat is high, you are faced with a COMPLIANCE problem
If your Pplat is N, you are faced with a RESISTIVE problem
DD?
Trouble Shooting
1. Give an ativan to the nurse!
2. Give haldol 10mg to the patient!
3. Take 5mg of morphine for yourself!
4. Look at your pt!
Trouble Shooting
At the time of intubation, fighting is largely due to anxiety
But what do you do if pt is stable and then becomes agitated?
Trouble Shooting
1. Remove pt from ventilator
2. Initiate manual ventilation
3. Perform P/E and assess monitoring indices
4. Check patency of airway
5. If death is imminent, consider and treat most likely causes
6. Once pt is stabilized, undertake more detailed assessement and management
ConclusionType of patient Tidal Volume RR PEEP FIO2 Ins. Flow I:E Note Note
Normal 10 cc/kg 10 to 12 0 to 5 100%. 60 l/min 1:2.
ARDS 6 cc/kg 10 to 12 5 to 15 100%. 60 l/min 1:2.
COPD 6 cc/kg 10 to 12 5 to 10 100%. 100 to 120 1:3 to 1:4 PH>7.2PCO2 <80 mmhgTrigger to consider
Trauma 10 cc/kg 10 to 12 0. 100%. 60 l/min 1:2.
Pediatric 8-10 cc/kg Varies age 3 to 5 100%. 60 l/min 1:2. Trigger to consider