1. Alyssa Morris, R4 July 15, 2010 Thanks to Dr J Lord

2.  Indications for ventilation  Ventilation terminology  Ventilation modes  NIPPV  IPPV*  Cases  ARDS  Metabolic acidosis  Asthma  SCM order sets

3.  Rosen’s Chapter 1 1. Failure to maintain or protect the airway 2. Failure of oxygenation or ventilation 3. Anticipated clinical course and potential for deterioration

4.  f, RR = breaths per minute  V E = V T x f (minute volume)  Amount of air that moves in and out of lungs/min  6-10L/min  V T = V A + V D  4-10cc/Kg IBW  FiO2= fractional concentration of inspired oxygen  0.3-1.0  decrease to 0.6 or less asap

5.  PEEP= positive end expiratory pressure  5-20 cmH20  Set vs. auto/intrinsic PEEP  P insp = set inspiratory pressure  I time= inspiratory time (0.8-1.7s)  E time= expiratory time  I:E Ratio= I time : E time

6.  Peak Inspiratory Pressure (PIP)  Occurs during inspiration  >35cmH20 leads to alveolar over-distension/injury  Plateau Pressure  Measured by occluding vent for 3-5 sec at end of inspiration  Should not exceed 30cmH20  Paw-mean= mean airway pressure= MAP  Corresponds to area under the curve in P over T curve  Correlates with O2 delivered  Inc I time = inc mean peak pressure= inc O2 delivery per ventilation

10.  NIPPV  CPAP ▪ Hypoxemic resp failure ▪ Increasing the compliance decreases the WOB ▪ Start at a pressure of 0-15ccH2O and increasing as tolerated to decrease FiO2  BiPAP ▪ Combo of CPAP and pressure support ventilation ▪ use in fatigued pt b/c >support during inspiration ▪ IPAP/EPAP (ex start at 10/5 or 12/6) ▪ Has to be a pressure gradient of at least 5 ▪ Increase IPAP as tolerated

11.  Indications for NIPPV (2 or more of):  pH 44mmHg  respiratory distress with moderate to severe dyspnea  RR>25

12.  Contraindications  Cardiac or respiratory arrest  Non-respiratory organ failure  Severe encephalopathy (GCS<10)  Severe UGIB  Hemodynamic instability or dysrhythmia  Facial surgery or trauma or deformity  Upper airway obstruction  Inability to cooperate/protect airway  Inability to clear secretions  High risk for aspiration

13.  IPPV  Volume-Cycled ▪ Ventilator seeks to deliver a constant preset V T ▪ Do not take into account lung compliance  Pressure-Cycled ▪ Ventilator alters gas flow to achieve a preset airway pressure over a preset I time ▪ Variable volumes are delivered to not exceed preset airway pressure ▪ Reduces alveolar overdistension  Combination Pressure-Volume cycled

14. Mode Volume-cycled Pressure-cycled CMV BothPSV AC SIMV PCV MMV

15.  Controlled Mechanical Ventilation  Apneic, paralyzed, anesthetized patients  Vent provides breaths at a set rate regardless of pt effort ▪ Each breath is triggered, limited and cycled by the vent  Rarely used now

17.  Assist Control  Ventilator delivers preset V T at a set minimum rate  If patient attempts breath, vent delivers a full breath at the preset volume/pressure ▪ AC-PC ▪ AC-VC  Common initial setting  Preset RR- patient can breath above or machine will ensure gets preset rate Q: Can you see any problems that could arise with this setting?

18.  AC-VC  Every breath is a controlled volume preset mandatory breath  Need to have normal lung and chest wall compliance  Advantage ▪ When minute volume requirements are high (ie. metabolic acidosis)  Disadvantages ▪ High peak pressures when compliance is low

19.  AC-PC  Every breath is a controlled pressure preset mandatory breath  Indications ▪ High pressures when using AC-VC ▪ Inverse ratio ventilation ▪ ALI/ARDS  Advantage ▪ Airway pressure will not exceed level of set pressure  Disadvantage ▪ When lung/chest compliance falls V T drops and hypercapnia may occur

21.  Pressure Support Ventilation  Use only in spontaneously breathing pts  Pressure support is given by vent on each patient initiated breaths  More comfortable  Might not get enough volume, reach mean airway pressure (decreased oxygentation)  Use when weaning

23.  Synchronized intermittent mandatory ventilation  Pt receives only the set number of volume controlled mandatory breaths which are synchronized with the pt  Additional breaths above set rate are pressure supported  More comfortable way to deliver volume controlled mandatory breats  Can use in inverse ratio ventilation and ALI/ARDS or pts with periodic apnea

25.  Mandatory Minute Ventilation  Pressure support ventilation with a volume-controlled back-up rate: ▪ Set minimum minute ventilation ▪ If patient breathing above this, all PSV breaths ▪ If patient not meeting minimum, volume- controlled breath(s) delivered to ensure MV

27.  No matter what mode of ventilation you use, certain settings will need to be considered:  Tidal volume  RR  PEEP  FiO2  I:E

28.  Tidal Volume  Normal lung- 8-10cc/kg IBW  Diseased lung – 6-8cc/kg IBW  RR  Usually start at 10-12/min ▪ Exceptions: metabolic acidosis, asthma, ARDS  Base on the patient need and PaCO2 on gas  FiO2  Start at 85-100% and quickly wean to 60%  SaO2 goal usually >92%

29.  PEEP  “physiologic” PEEP = 5cmH2O  Use 5 as a minimum  More depending on FiO2, intrinsic lung dz, extra- thoracic pressure  PEEP trial at the bedside ▪ Can use more to help wean to Fi02<60%  SE: ▪ Increases intrathoracic pressure  decreased venous return  decreased cardiac output

30.  I:E  In normal spontaneous breathing it is 1:4  In intubated pt it is set at 1:2 to 1:4  Sensitivity  Negative pressure required to trigger delivery  Usually set at 1-2cmH2O  Intrinsic PEEP makes it harder for the vent to sense a pt triggered breath

31.  Adjusting the vent  pCO2 too high  pCO2 too low  PO2 too high  pO2 too low

32.  Patient’s minute ventilation is too low 1. Increase rate or V T or both 2. Improve dead space 3. Decrease production: decrease temp, stop seizures, decrease feeds  Sometimes you have to live with the high pCO2 (Permissive hypercapnea)  Target pH >7.2  May need bicarb infusion if pH <7.2

33.  Minute ventilation is too high  Lower either the rate or tidal volume  Consider pain control or treating anxiety

34.  Your settings are working great  Turn down the FiO2

35.  Increase the FiO2 or mean airway pressure  Try to avoid FiO2>70%  To increase MAP 1.Increase PEEP 2.Change modes and increase inspiratory pressure or I time 3.Recruitment maneuvers

36. QUESTIONS?

37.  58M with 4d Hx of fever, productive cough and anorexia.  O/E: T= 39.2, P= 111, RR= 32, 02= 91% NRB, BP= 110/75  He looks very very tired and has decreased AE thru’ out  PMHx: HTN  Meds: HCTZ

39.  What is the definition of ALI and ARDS?  What is your mode of airway management?  What are your settings going to be?  V T  PEEP  FiO2  RR  I:E

40.  Objective  Determine whether ventilation with lower tidal volumes would improve the clinical outcomes in pts with ALI/ARDS

41.  Inclusion  Intubated and mechanically ventilated  Acute decrease in PaCO2/FiO2 <300  Bilateral pulmonary infiltrates w presence of edema  No evidence of increased L atrial HTN

42.  Exclusion  >36hrs since they met the above criteria  <18  Enrolled in other trials  Pregnant  Increased ICP  Neuromuscular dz  Sickle cell dz  Severe chronic respiratory dz  Burns >30% BSA  Bone marrow or lung transplant  Any condition w 6m survival <50%  Chronic liver dz

43.  METHOD  RCT  Vent Procedures ▪ AC until weaned or for 28 days minimum ▪ Control: 12cc/kg predicted weight with a plateau pressure of 50cmH20 ▪ They could decrease by 1cc/kg to maintain pressure goal ▪ Treatment: 6cc/kg predicted weight w/I 4 hrs of randomization with a plateau pressure of 30cmH20 ▪ Could only increase to 8cc/kg to maintain pressure goal ▪ Could give HCO3 for acidosis  Monitored for 28d

44.  Outcomes  Death before pt was d/cd home and was breathing w/o assistance  Number of days w/o ventilator use from D1-28  # of days w/o organ or system failure and the occurrence of barotrauma  Results  N= 861

46.  Low V T of 6cc/kg IBW in first 4h  Plateau airway pressure of 30cmH20  Increased RR  Maintains adequate minute ventilation  Permissive hypercapnea  PEEP  Higher than you would think  And decreased I:E ratio  1:1 to 1:3

49.  32F with known asthma comes in in respiratory distress.  O/E: T= 36.6, P= 112, RR= 29, Sa02= 90%  Looks terrible, ++ accessory muscle use  You have tried aggressive bronchodilators, steroids, fluids, Mg but she is failing and needs airway management.

50.  Is there a role for NIPPV in asthma?  How will you vent this patient?  V T  PEEP  FiO2  RR  I:E

51.  Well proven in AECOPD, so theoretically should work in asthma  No RCT, few small studies  2 very small prospective studies showed benefit  Cochrane concluded that it remains controversial despite some promising evidence  Ideal pt  Moderate resp distress  pH 7.25-7.35, PaCO2 45-55

52.  Goal: adequate oxygenation and minimizing hyperinflation  No RCT to guide mode and settings  “Controlled hypoventilation” and “permissive hypercapnia” with resultant acidosis  Minute ventilation that maximizes E time but provides enough ventilation to keep PaCO2 and pH reasonable  Reduces intrinsic PEEP and plateau pressures

54.  E time most nb determinant of hyperinflation  Maximize E time by shortening I time ▪ Increasing the insp flow rate and using a constant flow pattern  Increase E time by reducing RR

57.  24F with type I DM, in DKA, altered LOC, not protecting airway.  O/E: T= 38.1, P= 113, RR= 29, O2= 93%, BS= 34, BP= 110/60, GCS= 7  pH= 7.1

58.  What mode of ventilation will you use?  What will your settings be?  V T  PEEP  FiO2  RR  I:E