急诊医学教学课件：MechanicalVentilation

1、南南 京京 医医 科科 大大 学学 第第 二二 临临 床床 医医 学学 院院 ICUICU T h e S e c o n d A f f i l i a t e d H o s p i t a l o f N a n j i n g M e d i c a l U n i v e r s i t y T h e S e c o n d C l i n i c a l M e d i c a l S c h o o l o f N a n j i n g M e d i c a l U n i v e r s i t y Mechanical Ventilation What is mecha

2、nical ventilation？ Mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. Home made ventilator 2013年01月30日 新华每日电讯5版 from Xinhua news 18/min 1080/hour 25,920/day Died Tragically ? http:/ change oxygen unskillfully 2000-8-23 Nurse changed oxygen unskillfully ,patie

3、nt died ventilator leak 2001-5-8 ventilator leaked, patient died. trachea tube unmatche with ventilator 2004-01-28 trachea tube unmatched with ventilator ,patient died. 1600 years ago 塞两鼻孔，以芦管纳其口中 至咽，令人嘘之。有倾，其 中砻砻转，或是通气也 Plug two nostrils, insert a reed into the mouth to the pharynx , then blow air

4、into it, after a while , the respiration will come back again 葛洪Ge Hong肘后救卒方(a doctor , alchemist, regard as a immortal in Jin dynasty) (284364) 400 years ago- “ an opening must be attempted in the trunk of the trachea, into which a tube of reed or cane should be put; you will then blow into this, s

5、o that the lung may rise again and the heart becomes strong” -Andreas Vesalius (1555) a anatomist, physician, and author of one of the most influential books on human anatomy, De humani corporis fabrica (On the Structure of the Human Body). 80 years ago The iron lung was created by Philip Drinker an

6、d Louis Agassiz Shaw, two Harvard University researchers. The first iron lung was installed at Bellvue Hospital in New York City in 1927. Polio epidemic of 1955 negative-pressure tank ventilators ( Iron Lungs). Decreasing mortality from more than 80% to approximately 40% 协和医院病中即事 1937 年烧电线似有因，电灯倏灭仅三

7、分。年烧电线似有因，电灯倏灭仅三分。 医师护士都失色，吓煞邻厢铁肺人。医师护士都失色，吓煞邻厢铁肺人。 (美国富豪史奈特之子在铁肺中疗治数年， 邻余病室。) 岭南画派”名家高剑父，当时住在协和医 院 倏倏 shu What can they do on a ventilator? Blinky, Less Light, a childrens book using a voice activated computer, 32 pages took 10 years about 100,000 copies of the book have been sold. Dianne Odell die

8、d after 61 year battle Dianne Odell (February 13, 1947 May 28, 2008) polio at age 3 in 1950 Odell died on May 28, 2008 at age 61. A power failure and the failure of an emergency generator cut off her breathing devices functions. Family members attempted to use the emergency hand pump attached to the

9、 iron lung to keep her breathing, but their efforts were unsuccessful Noninvasive ventilation (NIV) A pump？ The ventilator simulates four stages four stages of breathingof breathing: 1. The ventilator or the patient triggers the initiation of inspiration. 2. The ventilator provides a breath, determi

10、ned by preset variables (eg, pressure, volume, and flow rate). 3. The ventilator halts inspiration when a preset parameter, such as tidal volume, inspiratory time, or airway pressure, is reached. 4. The ventilator switches to expiration and the breath is completed. Outline 1.Principles* 2.Methods of

11、 connection 3.Modes 4. Options 5.Alarms 6.Dyssynchrony 7.Weaning 1.Principles 1.1Objectives and Indications * 1.2Contraindication* 1.3Classification 1.4 Ventilator-Induced Lung Injury 1.5Physiologic effects of Positive Pressure ventilation 1.1 Objectives and indications* When and why do we use MV？ 1

12、.1.1 Reverse hypoxemia 1.1.2 Reverse respiratory acidosis 1.1.3 Prevent Atelectasis, keep lung volume. 1.1.4 Decrease the work of breathing 1.1.5 Stabilize chest cavity 1.1.6 Respiration backup for sedation and neuromuscular blockade 1.1.1 Reverse hypoxia Hypoxia=Cyanosis？ NO！ Cyanosis is not accura

13、te ! It happen when the reduced hemoglobin 40g/L. What about COPD patients? What about anemia patients? 1.1.2 Reverse respiratory acidosis Symptoms and Signs of Hypercarbia 1.1.3 Prevent Atelectasis, keep lung lung volumevolume. (functional residual capacity) 1.1.4 Decrease the workwork of breathing

14、 (normal 5% WOB/total ) Tachypnea, Dyspnea, Use of accessory muscles, Nasal flaring, Sweating, Tachycardia 1.1.5 Stabilize chest cavityStabilize chest cavity (for paradoxical respiratory movement in multiply rib fracture, flail chest) 1.1.6 Respiration backup for drug use Dr. Conrad Murray, the infa

15、mous doc whos criminally charged in Michael Jacksons death When you use sedation, muscle relaxant. 1.2 Contraindication* No absolute contraindication! 1.2 Contraindication* 1.2.1 Pneumothorax Do not MV Before thoracocentesis a large-bore (16 or 18 gauge) catheter is introduced in the midclavicular l

16、ine at the second or third intercostal space. 1.2.2 bullae of lung 1.2.3 Hemoptysis 1.2.4Hypovolemic Shock Why? 1.3 Classification 1.3.1 Control mechanical ventilation (CMV) versus assistant mechanical ventilation (AMV) 1.3.2 Negative-(The iron lung and chest cuirass) versus Positive-pressure ventil

17、ation Audrey King; 1958 polio 1.3.3 Invasive versus noninvasive A girl who have Spinal Muscular Atrophy 1.4 Ventilator-Induced Lung Injury1.4 Ventilator-Induced Lung Injury Normal Rat Lung after receiving High-Pressure Mechanical Ventilation Peak airway pressure 45 cmH2O Atul Malhotra, M.D., NEJM 35

18、7;11, p. 1114, 2007 mechanical ventilation for eight weeks tidal volumes of 12 to 15 ml per kilogram of body weight, peak airway pressures of 50 to 70 cm of water, positive end- expiratory pressures of 10 to 15 cm of water, fractional inspired oxygen concentration of 0.80 to 1.00 paramediastinal pne

19、umatocele in the right lung (Panel A, arrowheads) numerous intraparenchymal pseudocysts in the left lung (Panel B, black arrow, open circle, and asterisk) Tobin, Martin J. Advances in Mechanical Ventilation. New England Journal of Medicine 344, no. 26 (2001): 1986-1996. Pathogenesis of VILIPathogene

20、sis of VILI Atelectrauma : repetitive recruitment and de- recruitment Barotrauma : overdistention, air leak Biotrauma : or biochemical trauma, possibly induced by physical damage, is an inflammatory process with systemic consequences Protective ventilationProtective ventilation Malhotra A,et al.N En

21、gl J Med 2007 Protective ventilationventilation* * n Low tide volume: 6ml/kg（4-8 ml/kg）(vs nomal 6- 10ml/kg) (decrease ventilator-Induced Lung Injury) nHigh PEEP(Prevention of Alveolar Collapse) nP plate 30-35cmH2O nPermissive hypercapnia Malhotra A,et al.N Engl J Med 2007 1.5 Physiologic effects of

22、 Positive Pressure ventilation 2.Methods of connection Face Mask Nasal mask laryngeal mask Endotracheal intubation(oral , nasal)* tracheostomy tube 2.1 Face mask Non-invasive Stomach overextension Skin ulcer(Too tight), leak(too loose) Positive-Pressure Ventilation with a Face Mask and a Bag-Valve D

23、evice n engl j med 357;4 july 26, 2007 Oropharyngeal and Nasopharyngeal Airways Measuring the oral airwayMeasuring the oral airway Positioning the maskPositioning the mask ventilation cautioncaution 2.2 Nasal mask More comfortable Not impact drink, eat, expectoration 2.3 laryngeal mask

24、Less gas distension Non-invasive 2.4 Endotracheal intubation(oral , nasal) Oral: Most common Nasal: more VAP (ventilator associated Pneumonia) 2.5 Tracheostomy tube Long term ventilation More Comfortable More invasive 3.Mode Mode refers to the manner in which ventilator breaths are triggered, cycled

25、, and limited. The trigger, either an inspiratory effort or a time- based signal, defines what the ventilator senses to initiate an assisted breath. Cycle refers to the factors that determine the end of inspiration. Mandatory breath: started, controlled,ended by the ventilator Assisted breath: start

26、ed bynpatient, controlled, ended by the ventilator Spontaneous breath:started, controlled,ended by the ventilator(the volume of the breath delivered by the ventilator is determined by the patients effort and physiologic reserve. IPPV CPAP IMV /SIMV BiPAP PSV 3.1 Intermittent positive pressure ventil

27、ation (IPPV) Intermittent positive pressure ventilation (IPPV)* Generic term for all types of positive pressure ventilation Controlled mandatory ventilation (CMV) Most basic classic form of ventilation Pre-set rate and tidal volume Does not allow spontaneous breaths Appropriate for initial control o

28、f patients with little respiratory drive, severe lung injury or circulatory instability * 3.2 Pressure controlled ventilation (PCV) Pressure controlled ventilation (PCV) Pre-set rate; pre-set inspiratory pressure Tidal volume depends on pre-set pressure, lung compliance and airways resistance Used i

29、n management of severe acute respiratory failure to avoid high airway pressure 3.3 Synchronized intermittent mandatory ventilation (SIMV) Synchronized intermittent mandatory ventilation (SIMV) Pre-set rate of mandatory breaths with pre-set tidal volume Allows spontaneous breaths between mandatory br

30、eaths Spontaneous breaths may be pressure-supported (PS) Allows patient to settle on ventilator with less sedation 3.4 Pressure support ventilation (PSV) Pressure support ventilation (PSV) Breaths are triggered by patient Provides positive pressure to augment patients breaths Useful for weaning May

31、be combined with SIMV Pressure support is titrated against tidal volume and respiratory rate 3.5 Continuous positive airways pressure (CPAP) Continuous positive airways pressure (CPAP) Positive airway pressure applied throughout the respiratory cycle (via either an endotracheal tube or a tight-fitti

32、ng facemask ) Fresh gas flow must exceed patients peak inspiratory flow Improves oxygenation by recruitment of atelectatic or edematous lung Mask CPAP discourages coughing and clearance of lung secretions; may increase the risk of aspiration 3.6 Bi-level positive airway pressure (BiPAP/BIPAP) Bi-lev

33、el positive airway pressure (BiPAP/BIPAP) In fully ventilated patients, BiPAP is essentially the same as PCV with PEEP In partially ventilated patients, and especially if used non-invasively, BiPAP is essentially PSV with CPAP How to select Mode 1.Oxygen 2.CO2 3.respiratory muscle strength 4.airway

34、resistance 5.weaning 6.chronic pulmonary disease 4. Options 4.1Frequency (F) 4.2Tidal volume (Vt) and minute ventilation (MV) 4.3Inspiratory: expiratory (I : E) ratio 4.4Sensitivity 4.5 PEEP 4.6FIO2 4.1 Frequency 4.1.1. The respiratory rate and tidal volume determine minute ventilation. 4.1.2. Set t

35、he rate at 12 to 25/min to achieve a MV(minute ventilation=Tide volume*f) of 5 to 10 L/min. 4.1.3. Adjust the rate to achieve the desired pH and PaCO2. 4.2 Vt and MV A tidal volume target of 6 to 10 mL/kg predicted body weight is used. Ideal body weight is determined by the height and the sex of the

36、 patient. Please match 5mL/kg (Low， 4-8 mL/kg) 6 to 8 mL/kg with. 8 to 10 mL/kg（high） ARDS. neuromuscular disease or postoperative ventilatory support. obstructive lung disease 4.3 Inspiratory: expiratory (I : E) ratio Which is right？ 4.3.1. The expiratory time generally should be (shorter or longer

37、) than the inspiratory time. 4.3.2. The expiratory time should be (shortened or lengthened) if the blood pressure drops in response to positive-pressure ventilation or if auto-PEEP is present. 4.3.3. Longer inspiratory times (increase or decrease) mean airway pressure and may improve arterial partia

38、l pressure of oxygen (PaO2) in some patients. Answer: 1.longer (I:E 1:1.5- 1:2),2.lengthened,3.increase 4.4 Sensitivity 4.4.1 Sensitivity adjusts the level of negative pressure required to trigger the ventilator. 4.4.2 A typical setting 1 3L/min(quantitative ) or -1 -2 cm H2O(pressure). 4.4.3 Too hi

39、gh a setting causes weak patients to be unable to trigger a breath. 4.4.4 Too low a setting may lead to overventilation by causing the machine to auto- cycle. 4.5 Positive End-Expiratory Pressure (PEEP) For Qs/Qt( shunt/total) hypoxia, especially ARDS PEEP* 4.5.1 PEEP increases end-expired lung volu

40、me and reduces airspace closure at the end of expiration. 4.5.2 PEEP at 5 cm H2O to limit the atelectasis 4.5.3 Higher levels of PEEP improve oxygenation in disorders such as cardiogenic pulmonary edema and ARDS. PEEP vs Auto-peep Set PEEP =80%auto-PEEP For COPD and asthma 4.6 Fraction of inspiratio

41、n O2 Does life like oxygen？ Hyperoxia increase mortality Kilgannon, J. H. et al. JAMA 2010;303:2165-2171 Figure. In-Hospital Death Between Hyperoxia and Normoxia Kilgannon, J. H. et al. JAMA 2010;303:2165-2171 Rincon, F., J. Kang, M. Maltenfort, M. Vibbert, J. Urtecho, M. K. Athar, J. Jallo, C. C. P

42、ineda, D. Tzeng, W. McBride and R. Bell. Association between Hyperoxia and Mortality after Stroke: A Multicenter Cohort Study. Crit Care Med 42, no. 2 (2014): 387-96. FiO2 4.6.1.Initiate mechanical ventilation with an FiO2of 1.0. 4.6.2.Titrate the FiO2using pulse oximetry. 4.6.3.Inability to reduce

43、the FiO2 to less than 0.6 indicates the presence of shunt (intrapulmonary or intracardiac). Alarm 5.1. Vt or MV alarm 5.2. Pressure alarm (high and low) 5.3.FIO2 alarm 6. Dyssynchrony 6.1 Cause of patient: hypoxia did not corrected Acute left heart failure Central nervous system disease Chough, obst

44、ruction Nervous Acidosis Increase of oxygen demand : fever ,epilepsy Dyssynchrony 6.2 Cause of ventilator: synchronization function of the machine Trigger Leak 6.3 Management of Dyssynchrony Ventilator Patient: Sedation muscle relaxant Weaning 21:0021:12 21:34 7.1 Screen for weaning 7.1.1 Lung injur

45、y is stable/resolving, 7.1.2 Gas exchange is adequate with low PEEP and FIO2 (PEEP8 cmH2O and FIO2 0.5), 7.1.3 Hemodynamic variables are stable (patient off vasopressors), 7.1.4 Patient is capable of initiating spontaneous breaths. This screen should be done at least daily. 7.2 Spontaneous breathing

46、 trial (SBT) 10 cmH2O PSV 30min or 2hour 7.3 Removal of the artificial airway 7.3.1 The ability to protect the airway, to cough and clear secretions, and is alert enough to follow commands. 7.3.2 Other factors must be taken into account, such as the possible difficulty in replacing the tube. 7.3.3 1015% of