You are following a 39 year old female on mechanical ventilation for pneumonia. She is on a propofol gtt and is minimally responsive. Her ABG reveals 7.43/46/88/30/95% on AC 22/8/500/50%. She is hemodynamically stable but does have some secretions.
Questions:
1. How do we assess the patient to determine if she can tolerate a SBT?
2. It is determined that she can attempt an SBT. At the end of the SBT her TV is 300, NIF -12, and RSBI is 100. ABG revealed 7.28/50/80/30/94% on 8/5 + 30%. Would you extubate her? What other information would be helpful in making a decision?
Criteria for extubation: Spontaneous breathing for > 30 minutes, airway anatomy intact, strong cough, small amount of secretions, cuff leak present and intact mentation
ReplyDeleteUnderlying condition that caused intubation has reversed
PaO2 > 60
FIO2 < 40
PaO2/FIO2 > 150-200
PEEP < 5
pH > 7.25
RSBI < 105 (Rapid shallow breating index = respiration rate/tidal volume) (best indicator)
NIF < -20 (Negative inspiratory flow)
Negative indicators: RR > 35 for 5 minutes, O2 sat < 90, HR > 140, change in HR of > 20%, SBP > 180 or < 90, anxiety and diapheresis
Place vent in pressure support, CPAP or no PEEP mode for at least 30 minutes.
I would not extubate this patient at this time. Her PEEP is still 8 and it would be better to have a PEEP of 5. Her NIF is not below -20, her RSBI is borderline and she has low TV's as well as secretions. A full set of vital signs, physical exam and a cuff leak would help in this decision. Steroid therapy prior to extubation if patient fails cuff leak test.
Uptodate, dynamed
Ventilator weaning and spontaneous breathing trials; an educational review, zein et all, emerg 2016 spring 4(2): 65-71
Weaning Patients from the Ventilator, McCOnville et al, New England Journal of medicine 2012: 367:2233-2239
1. Required criteria for readiness to begin spontaneous breathing trial according to uptodate consist of: cause of respiratory failure is improved, PaO2/FiO2≥150* or SpO2≥90 percent on FiO2≤40 percent and positive end-expiratory pressure (PEEP) ≤5 cmH2O, ph >7.25, hemodynamicly stable and able to initiate inspiratory effort.
ReplyDeleteThis patient is hemodynamically stable, Peep is 5, and pH is appropriate.
For this patient pneumonia would need to be resolved, she would also need to be able to follow commands when not sedated and her Sp02 is still too high. She is not ready to begin spontaneous breathing trial.
Another consideration made by uptodate is that 30% of patients that don’t meet criteria and are successfully extubated.
2. RESBI is not >105, PaO2/FiO2 is > 238, which are indicators that the patient has weaned. Cough strength would need to be assessed, airway patency and ability to protect airway. The patient is acidotic with an increase in co2 retention. I would attempt to extubate to bipap.
To tolerate an SBT, she needs to be responsive and be able to follow commands (be awake and arousable, moving toes, squeezing hands) off sedation. She also needs to be hemodynamically stable (SBP at least 90 off all pressors, HR 140 or less, afebrile, no excessive trachea-bronchial secretions). The patient’s underlying condition that put them in respiratory failure has to also have resolved. For her vent settings, her peep should be 5-8 or less and Fio2 should be less than 50%. The abg should not show any significant respirator acidosis (pH of 7.3 or greater)
ReplyDeleteI would not extubate this patient. The standard weaning criteria include:
1. RSBI: Less than or equal to 105
2. NIF: Less than or equal to -20
3. Spontaneous tidal volume: Greater than or equal to 5 mL/kg
4. Vital Capacity: Greater than or equal to 10 or 15 mL/kg
Assuming she is at least 70 kg, her spontaneous tidal volume should be at least 350. Her RSBI is less than 105, but just barely. Studies show that the lower the RSBI predicts a higher chance of extubation success. Her NIF should be less than -20, but is actually higher. Other information that could help in making a decision are if the underlying cause of her respiratory failure have resolved (pneumonia, pulmonary edema, etc.), how adequately she is following commands off sedation, Pao2/Fio2 ratio of 150-200 or greater, how she clinically sounds on lung exam (wheezing, stridor). Try to treat the underlying cause of weaning difficutly (hypoxemia, increased resistive work of breathing from asthma/COPD, increased elastic work of breathing from pulmonary edema/heart failure, decreased neuromuscular capacity).
Sources:
https://pulmccm.org/review-articles/weaning-from-mechanical-ventilation-update-review-nejm/
https://www.cancertherapyadvisor.com/critical-care-medicine/difficulty-weaning-from-mechanical-ventilation-failure-to-wean-respiratory-failure-ventilator-dependence/article/585141/
https://www.nejm.org/doi/full/10.1056/NEJMra1203367?utm_medium=referral&utm_source=r360&utm_campaign=criticalcare
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4893753/
http://www.rcjournal.com/contents/07.04/07.04.0830.pdf
Patient that pass the following daily wean screen should undergo SBT
ReplyDeleteLung disease is stable/ resolving.
Low Fio2 <0.5 and PEEP <5-8 cmH2O requirement.
Hemodynamic stability
Able to initiate spontaneous breaths (good neuromuscular function)
The following is the criteria to stop SBT. No single parameter should be used to judge SBT success and failure but a combination of the following are often used.
Respiratory rate > 38 bpm for 5 minuets or < 6bpm.
SpO2 < 92%
Tidal volume < 325 ml
HR > 140 or < 60
SBP 40 mm Hg above baseline
Worsening agitation, anxiety or discomfort despite reassurance.
Rapid shallow breathing index (RSBI) = RR/ TV . Most powerful predictor. RSBI > 105
min / L predict failure well.
I will not extubate the patient because she is meeting 2 parameters of SBT failure . Her tidal volume is 300 that is less than 325 and her NIF is -12 that is not less than -20 . Her RSBI is border line better.
My reference is LITFL review 330 . Life in the fast lane is a site with good review of emergency medicine and critical care topics.
1. The cause of the respiratory failure has improved
ReplyDelete2. P/F >= 150 or Spo2 >=90% while receiving Fio2 <=40% and Peep <=5
3. Arterial ph >7.25
4. Hemodynamic stability
5. Able to initiate inspiratory effort
6. Awake and alert or easily arousable.
I would give her another day or at least wean down her FiO2 and peep and see how she tolerates it by repeating her ABG. Would want to know if she has lots of secretions, if she is able to protect her airways, has a strong cough, if her overall condition is improved, or if she is arousable off propofol drip.