PC mode 2

1. Mechanical Ventilation
- PC mode -
EICU core review 전임의 김태권

2. Mechanical Ventilation
- Weaning -

3.  Prolonged MV associated with significant morbidity & mortality
- Ventilator associated pneumonia (VAP)
- Respiratory & general muscle weakness
- Length of stay↑ (ICU & Hospital)
- Long term care facility use↑
Why weaning is important ?

4. 7 stages of weaning

5. 7 stages of weaning

6. Weaning Indication : Preweaning

7. 7 stages of weaning

8.  원인 질환의 급성기에서 호전된 상태인가?
 적절한 기침이 가능한가?
 기관지 분비물이 과다하지는 않은가?
Suspicion : 임상적 평가

9. Lancet 2008; 371: 126–34
Wake Up & Breathe protocol
Spontaneous Awakening Trials (SATs)
+
Spontaneous Breathing Trials (SBTs)
 All sedatives and analgesics used for sedation are interrupted
 Analgesics needed for active pain are continued
 Monitored for up to 4h
[SAT + SBT] [Usual care + SBT]

10. 7 stages of weaning

11. (Vital capacity)
(Minute ventilation)
(Respiratory rate)
(Tidal volume)
(Rapid shallow breathing index)
 RSBI (RR/VT (L)) < 105
(measured without ventilator support)
 얕고 빠른 호흡 일수록 weaning 실패 가능성↑
Weaning Indication : Parameters
 RSBI (RR/VT (L)) = 30/0.2 = 150 > 105
RSBI는 음성예측도가 높음 (105보다 높을 시 실패 확률 높지만, 낮다고 성공 확률이 높은 것은 아님)
CPAP mode
CPAP 5cmH2O or PSV 5~8 cmH2O

12. (Vital capacity)
(Minute ventilation)
(Respiratory rate)
(Tidal volume)
(Rapid shallow breathing index)
Weaning Indication : Parameters  MIP (Maximal Inspiratory Pressure) ≤ -20 ~ -30 cmH2O
 호흡근의 근력 측정 : 최대한의 Negative Inspiratory Force를 측정함
 호기상태에서 Expiratory hold maneuver로 (-) pressure를 측정

13. 적절한 산소화의 유지
 SaO2 ≥ 90 % (FiO2 ≤ 40 %)
 P/F ratio ≥ 150~200
 PEEP ≤ 5 ~ 8 cmH2O
적절한 호흡 능력 (Clinical criteria + Weaning predictor)
 Patient is able to initiate spontaneous breaths
 RR ≤ 35 회/분
 MIP (maximal inspiratory pressure) ≤ -20 ~ -30 cmH2O
: 호흡근 근력 측정, 호기상태에서 Expiratory hold maneuver로 흡기 노력에 의한 (-) pressure를 측정
 VT > 4 ~ 6 mL/kg
 VE < 10 ~ 15 L/min (정상인 VE 5 ~ 6 L/min)
 Arterial pH > 7.25 (no significant respiratory acidosis)
 RSBI (RR /VT (L)) < 105 (measured without ventilator support)
: ventilator circuit의 resistance를 cover할 정도의 positive pressure상태에서 spontaneous
breathing으로 측정함. CPAP 5 cmH2O or PSV 3~5 cmH2O 정도를 적용 . RR/VT계산
음성예측도가 높음 (105보다 높을시 실패 확률 높지만, 낮다고 성공 확률이 높은 것 아님)
 Static compliance (VT / Pplat – PEEP) > 33 mL/cmH2O (정상 60~100)
Weaning Indication : Readiness to wean
혈역학적 안정성
 HR < 140 회/분
 Cause of respiratory failure has improved
 SBP 90~180mmHg
 Hemodynamic stable (without myocardial ischemia)
 No or low dose vasopressor medications
(Dopamine ≤ 5mcg/kg/min, NE ≤ 0.2mcg/kg/min)
 Core temperature ≤ 38 ~ 38.5 ℃
 Hb ≥ 8 ~ 10mg/dL
적절한 의식상태
 No sedation
 Adequate mentation on sedation
 Awake or alert or easily arousable (ideal for weaning)
 Abnormal mental state (GCS < 8 or inability to
follow simple command) does not appear to be
associated with higher rate of extubation failure
 Stable neurologic patient

14. 7 stages of weaning

15. Weaning Trial : Weaning method
Spontaneous Breathing Trial
Gradual reduction weaning method Gradual reduction weaning method

16. Best ventilator mode to wean on ?
 Evidence would suggest :
PSV ≈ Intermittent T-piece trial > SIMV
 T-piece trial : 30min trial ≈ 2 hour trial
SBT (Spontaneous Breathing Trial)
Weaning method
 SBT or Gradual reduction (= decreasing level of pressure support, 2~4 cmH2O per day)
 SBT is generally preferred, but gradual reduction may be better in certain situation
(장기간의 기계 호흡 사용을 사용으로 호흡근 약화가 예상되는 환자는 gradual reduction를 고려할 수 있음)
 SIMV alone not be used for weaning (not recommend for weaning mode)
 적절한 모니터링과 감시로 weaning failure를 일찍 감지하고 full MV support로 복귀시킨다면 complication은 발생하지 않음
 Weaning 실패시 원인을 파악하고 교정해야 함 & Daily assess for readiness to wean + SBT (Once daily, Not multiple times)

17. Daily SBT
1. Spontaneous breathing with T-piece
2. Spontaneous breathing with PS Mode 5 ~ 7 cmH2O (If ET tube size #7, use PS of 8~10 cmH2O)
3. Spontaneous breathing with Tube compensation Mode
4. Spontaneous breathing with CPAP (PEEP 5 cmH2O)
 Duration : 30min ~ 2hrs
SBT (Spontaneous Breathing Trial)
SBT with T-piece SBT with PS or TC or CPAP

18. SBT with monitoring

19. SBT failure
 RR > 35 회/분 for 5 min
 SaO2 < 90% for 30sec
 HR > 140 회/분 (or change of ±20% of baseline) for 5 min
 sBP > 180 or < 90 mmHg (sBP 30mmHg↑ or 20mmHg↓) for 5 min
 Agitation, Anxiety, Diaphoresis
 Chest pain or SOB (shortness of breath)
SBT (Spontaneous Breathing Trial)
 적절한 모니터링과 감시로 weaning failure를 일찍 감지하고 full MV support로 복귀시킨다면 complication은 발생하지 않음
 Weaning 실패시 원인을 파악하고 교정해야 함
 Daily assess for readiness to wean + SBT (Once daily, Not multiple times)
Sudden onset of PVC (> 4~6 회/min)

20. SBT (Spontaneous Breathing Trial)
 적절한 모니터링과 감시로 weaning failure를 일찍 감지하고 종료 후
full MV support (이전 mode)로 복귀시킨다면 complication은 발생하지 않음
 Daily assess for readiness to wean + SBT (Once daily, Not multiple times)
 Weaning 실패시 원인을 파악하고 교정해야 함

21.  Simple wean : 첫 SBT에 성공한 경우 (약 50~66%)
 Difficult to wean : 첫 SBT 실패 + SBT 성공에 최대 3회 + 6일 이내의 시간이 소요되는 경우 (약 26~40%)
 Prolonged weaning : 최소 3번 SBT 실패 or SBT 성공에 7일 이상이 소요 (약 10~20%)
 Prolonged weaning : In hospital & overall mortaliy ↑
 Prolonged weaning → Progressive reduction of PS level, progressive increasing duration of SBT, tracheostomy is performed
Difficult to wean
Difficult to wean의 원인 (기계 호흡을 적용하게 한 원인을 완전히 치료하지 못한 상태 or 추가적인 새로운 문제의 발생)
- Respiratory/Ventilatory causes : Ventilator demand↓, Reistive load↓, Compliance↓, Neuromuscular capacity↓, Ventilatory drive↓,
Auto-PEEP(COPD), Overventilation (COPD),
- Cardiac causes : Weaning induced myocardial ischemia (or HF), Pulmonary edema with HF (or ischemia), Fluid overload in normal heart
- Psychological causes : Depression, Anxiety, Delirium, Pain, Over-sedation
- Ventilator causes : Equipment dead space, ET tube luminal narrowing, Circuit compliance, Exhalation valve dysfx
- Nutritional causes : Underfeeding & protein catabolism → Respiratory m weakness, Overfeeding CO2 → production & Ventilatory load ↑

22. Extubation screening
+
(Cuff leak test)
7 stages of weaning

23. Extubation Screening
 Is patient awake & responsive to verbal command ? (consider sedation interruption, SAT)
 Can patient protect airway ? (Cough reflex intact ? Voluntary cough (strength) adequate to clear secretion ?)
 Suction frequency ? (check documentation in the prior 6~8 hrs, < q2h)
 Quantity & Quality of secretions ? (< 2.5 cc/h)
 Concerns about the patency of upper airway ? Perform standard cuff-leak test
 If NMD, Can patient sustain head life maneuver against resistance ?
 If patient failed repeatedly (to weaning trial or extubation screening), consider tracheostomy if intubated > 2 weeks
 Tracheostomy : Early airway suctioning, WOB↓, Patient comfort↑, Need for sedation↓, Communication↑
 Early tracheostomy (<4days) : No proven benefit (mortality, VAP, aspiration pneumonia, duration of MV)
Extubation screening

24. Post-extubation & Stridor (laryngeal edema)

25. Cuff leak test & laryngeal edema
1. VC mode를 선택 후 setting 한다
2. ET tube의 cuff 를 deflation 한다
3. 이 후 연속되는 6번의 호기 tidal volume을 체크
4. 이중 가장 수치가 낮은 tidal volume 3개의 평균을 구함
5. VT (setting값) – 호기 평균 VT = cuff leak volume
6. Cuff leak volume < 110 mL (< 12~24 % of VT)
→ laryngeal edema risk↑ → IV steroid
No audiable leak → laryngeal edema risk↑

26. Laryngeal edema & US
Laryngeal ultrasound in intubated pts at the level of cricothyroid membrane
Square-shaped air-column with
hyper-echoic air-column bands
Ding et al. Eur Respir J 2006; 27: 384–389
ET tube

27. US during ballon-cuff inflation US during ballon-cuff deflation
Normal patient (no stridor) Laryngeal edema patient (stridor)
US during ballon-cuff inflation US during ballon-cuff deflation
 No change in air column width
 Shape of the laryngeal air column was as square as the
image of cuff inflation
 The true cords and arytenoid cartilage were not
masked by the air column
Laryngeal edema & US
Ding et al. Eur Respir J 2006; 27: 384–389

28. Air-column width (0.57 cm)
immediately after intubation
with cuff deflated
Air-column width (0.42 cm) of 3h
before extubation
with cuff deflated
(Air column width ratio = 0.73)
Air column width ratio ≤ 0.8 : may be helpful in predicting post-extubation stridor
Laryngeal edema & US
This patient had stridor after extubation

29. Approach to cuff leak test & laryngeal edema

30. 7 stages of weaning

31. Post-Extubation & NIV
 Weaning Adjuncts : NIV, HFNO → WOB ↓ (support)
 Extubation → COPD, HFNO (Not alternative to re-intubation)
 NIV (Non-invasive ventilation) : Bilevel respiratory support or CPAP
- Mortality↓(esp. COPD), VAP↓, LOS↓(ICU & Hospital), Reintubation↓, Tracheostomy insertion↓
- COPD & Hypercapnic respiratory failure 환자는 SBT failure에도 weaning 후 NIV 적용을 고려해 볼 수 있음
 Patients at increased risk for extubation failure → preemptive NIPPV in the immediate post-extubation period → Effective in reducing need for reintubation
(If NIPPV is started after respiratory distress begins, may not benefit from NIPPV)
 HFNO (High flow nasal oxygen) : low level continuous positive airway pressure
- Higher P/F ratio, Ventilator free days↑, Re-intubation↓
- No difference in LOS & mortality
- Needs further evaluation

32. 7 stages of weaning

33.  Approximately 15% of patients required re-intubation within 48h
 Patients who required intubation : Risk of death↑, Hospital stay↑, Likehood of returning home↓
 Risk factor for re-intubation : inadequate cough, excessive secretion, poor mental state,
Positive fluid balance before extubation, diagnosis of pneumonia, RSBI↑ at the end of a SBT
 Physician’s judgment and experience are essential components in successful extubation
Re-Intubation

34. Post-Extubation & NIV + Reintubation
Aggressive Approach
 Extubation & Use of preemptive NIPPV (who had successful SBT + Risk of re-intubation)
 Reassess the patient within 30 min after initiating NIPPV
 If the RR is elevated or patient is in mild distress → Immediate re-intubation
(Delayed time to reintubation : associated with mortality among pts in whom discontinuation of ventilation has been unsuccessful)
 Benefits of earlier discontinuation of ventilation > Risk associated with waiting another 12~24 hours for continued clinical improvement