呼吸衰竭診斷指標(biāo)及救治措施高苑ppt課件

1、 respiratory failure 2 typeshypoxemic respiratory failurehypercapnic respiratory failurehypoxemic respiratory failurepao2 50 mmhg in an otherwise healthy individualaka “ventilatory failure”caused by increased wob, ventilatory drive, or muscle fatigueorofacial masks nasal masks full face masks nasal

2、pillowstotal face mask helmet mask. company logoprinciples of mechanical ventilationdavid m. lieberman, mdallen s. ho, mdsurgery icu servicestanford university medical centerseptember 25, 2006the basicscompany logonegative-pressure ventilators (“iron lungs”) non-invasive ventilation first used in bo

3、ston childrens hospital in 1928 used extensively during polio outbreaks in 1940s 1950spositive-pressure ventilators invasive ventilation first used at massachusetts general hospital in 1955 now the modern standard of mechanical ventilationthe era of intensive care medicine began with positive-pressu

4、re ventilationthe iron lung created negative pressure in abdomen as well as the chest, decreasing cardiac output.iron lung polio ward at rancho los amigos hospital in 1953.company logotheory ventilation vs. oxygenation pressure cycling vs. volume cyclingmodesventilator settingsindications to intubat

5、eindications to extubatemanagement algorithimfaqscompany logothe goal of ventilation is to facilitate co2 release and maintain normal paco2minute ventilation (ve) total amount of gas exhaled/min. ve = (rr) x (tv) ve comprised of 2 factors va = alveolar ventilation vd = dead space ventilation vd/vt =

6、 0.33 ve regulated by brain stem, responding to ph and paco2ventilation in context of icu increased co2 production fever, sepsis, injury, overfeeding increased vd atelectasis, lung injury, ards, pulmonary embolism adjustments: rr and tvv/q matching. zone 1 demonstrates dead-space ventilation (ventil

7、ation without perfusion). zone 2 demonstrates normal perfusion. zone 3 demonstrates shunting (perfusion without ventilation).company logothe primary goal of oxygenation is to maximize o2 delivery to blood (pao2)alveolar-arterial o2 gradient (pao2 pao2) equilibrium between oxygen in blood and oxygen

8、in alveoli a-a gradient measures efficiency of oxygenation pao2 partially depends on ventilation but more on v/q matchingoxygenation in context of icu v/q mismatching patient position (supine) airway pressure, pulmonary parenchymal disease, small-airway disease adjustments: fio2 and peepv/q matching

9、. zone 1 demonstrates dead-space ventilation (ventilation without perfusion). zone 2 demonstrates normal perfusion. zone 3 demonstrates shunting (perfusion without ventilation).company logopressure-cycled modes deliver a fixed pressure at variable volume (neonates)volume-cycled modes deliver a fixed

10、 volume at variable pressure (adults)pressure-cycled modes pressure support ventilation (psv) pressure control ventilation (pcv) cpap bipapvolume-cycled modes control assist assist/control intermittent mandatory ventilation (imv) synchronous intermittent mandatory ventilation (simv)volume-cycled mod

11、es have the inherent risk of volutrauma.company logopatient determines rr, ve, inspiratory time a purely spontaneous modeparameters triggered by pts own breath limited by pressure affects inspiration onlyuses complement volume-cycled modes (i.e., simv) does not augment tv but overcomes resistance cr

12、eated by ventilator tubing psv alone used alone for recovering intubated pts who are not quite ready for extubation augments inflation volumes during spontaneous breaths bipap (cpap plus ps) psv is most often used together with other volume-cycled modes. psv provides sufficient pressure to overcome

13、the resistance of the ventilator tubing, and acts during inspiration only.company logoventilator determines inspiratory time no patient participationparameters triggered by time limited by pressure affects inspiration onlydisadvantages requires frequent adjustments to maintain adequate ve pt with no

14、ncompliant lungs may require alterations in inspiratory times to achieve adequate tvcompany logocpap is essentially constant peep; bipap is cpap plus psparameters cpap peep set at 5-10 cm h2o bipap cpap with pressure support (5-20 cm h2o) shown to reduce need for intubation and mortality in copd pts

15、indications when medical therapy fails (tachypnea, hypoxemia, respiratory acidosis) use in conjunction with bronchodilators, steroids, oral/parenteral steroids, antibiotics to prevent/delay intubation weaning protocols obstructive sleep apneacompany logocontrol mode pt receives a set number of breat

16、hs and cannot breathe between ventilator breaths similar to pressure controlassist mode pt initiates all breaths, but ventilator cycles in at initiation to give a preset tidal volume pt controls rate but always receives a full machine breathassist/control mode assist mode unless pts respiratory rate

17、 falls below preset value ventilator then switches to control mode r a p i d l y b r e a t h i n g p t s c a n overventilate and induce severe r e s p i r a t o r y a l k a l o s i s a n d hyperinflation (auto-peep)ventilator delivers a fixed volumecompany logovolume-cycled modes typically augmented

18、 with pressure supportimv pt receives a set number of ventilator breaths different from control: pt can initiate own (spontaneous) breaths different from assist: spontaneous breaths are not supported by machine with fixed tv ventilator always delivers breath, even if pt exhalingsimv most commonly us

19、ed mode spontaneous breaths and mandatory breaths if pt has respiratory drive, the mandatory breaths are synchronized with the pts inspiratory effortcompany logofio2 simplest maneuver to quickly increase pao2 long-term toxicity at 60% free radical damageinadequate oxygenation despite 100% fio2 usual

20、ly due to pulmonary shunting collapse atelectasis pus-filled alveoli pneumonia water/protein ards water chf blood - hemorrhagepeep and fio2 are adjusted in tandemcompany logopeep increases frc prevents progressive atelectasis and intrapulmonary shunting prevents repetitive opening/closing (injury) r

21、ecruits collapsed alveoli and improves v/q matching resolves intrapulmonary shunting improves compliance enables maintenance of adequate pao2 at a safe fio2 level disadvantages increases intrathoracic pressure (may require pulmonary a. catheter) may lead to ards rupture: ptx, pulmonary edemapeep and

22、 fio2 are adjusted in tandemoxygen delivery (do2), not pao2, should be used to assess optimal peep.company logorespiratory rate max rr at 35 breaths/min efficiency of ventilation decreases with increasing rr decreased time for alveolar emptyingtv goal of 10 ml/kg risk of volutraumaother means to dec

23、rease paco2 reduce muscular activity/seizures minimizing exogenous carb load controlling hypermetabolic statespermissive hypercapnea preferable to dangerously high rr and tv, as long as ph 7.15rr and tv are adjusted to maintain ve and paco2i:e ratio (irv) increasing inspiration time will increase tv

24、, but may lead to auto-peeppip elevated pip suggests need for switch from volume-cycled to pressure-cycled mode maintained at 45cm h2o to minimize barotraumaplateau pressures pressure measured at the end of inspiratory phase maintained at 35 hypoxia: po2 55mm hg minute ventilation10 l/min tidal volu

25、me 5-10 ml/kg negative inspiratory force 25cm h2o (how strong the pt can suck in)initial vent settings fio2 = 50% peep = 5cm h2o rr = 12 15 breaths/min vt = 10 12 ml/kg copd = 10 ml/kg (prevent overinflation) ards = 8 ml/kg (prevent volutrauma) permissive hypercapnea pressure support = 10cm h2ohow t

26、he values trend should significantly impact clinical decisionscompany logoclinical parameters resolution/stabilization of disease process hemodynamically stable intact cough/gag reflex spontaneous respirations acceptable vent settings fio2 50%, peep 75, ph 7.25general approaches simv weaning pressur

27、e support ventilation (psv) weaning spontaneous breathing trials demonstrated to be superiorno weaning parameter completely accurate when used alonenumerical parametersnormal rangeweaning thresholdp/f 400 200tidal volume5 - 7 ml/kg5 ml/kgrespiratory rate14 - 18 breaths/min 40 breaths/minvital capaci

28、ty65 - 75 ml/kg10 ml/kgminute volume5 - 7 l/min - 90 cm h2o - 25 cm h2orsbi (rapid shallow breathing index) (rr/tv) 50 100 marino p, the icu book (2/e). 1998.company logosettings peep = 5, ps = 0 5, fio2 35 for 5 min sao2 30 sec hr 140 systolic bp 180 or 90mm hg sustained increased work of breathing

29、 cardiac dysrhythmia ph 7.32sbts do not guarantee that airway is stable or pt can self-clear secretionscauses of failed sbtstreatmentsanxiety/agitationbenzodiazepines or haldolinfectiondiagnosis and txelectrolyte abnormalities (k+, po4-)correctionpulmonary edema, cardiac ischemiadiuretics and nitrat

30、esdeconditioning, malnutritionaggressive nutritionneuromuscular diseasebronchopulmonary hygiene, early consideration of trachincreased intra-abdominal pressuresemirecumbent positioning, ngthypothyroidismthyroid replacementexcessive auto-peep (copd, asthma)bronchodilator therapysena et al, acs surger

31、y: principles and practice (2005).company logocommonly cited factorsaltered mental status and inability to protect airwaypotentially difficult reintubationunstable injury to cervical spinelikelihood of return trips to orneed for frequent suctioninginherent risks of intubation balanced against contin

32、ued need for intubationcompany logoadvantages issue of airway stability can be separated from issue of readiness for extubation may quicken decision to extubate decreased work of breathing avoid continued vocal cord injury improved bronchopulmonary hygiene improved pt communicationdisadvantages long

33、 term risk of tracheal stenosis procedure-related complication rate (4% - 36%)prolonged intubation may injure airway and cause airway edema1 - vocal cords. 2 - thyroid cartilage. 3 - cricoid cartilage. 4 - tracheal cartilage. 5 - balloon cuff.company logoinitial intubation fio2 = 50% peep = 5 rr = 1

34、2 15 vt = 8 10 ml/kgsao2 90%sao2 90% adjust rr to maintain paco2 = 40 reduce fio2 50% as tolerated reduce peep 8 as tolerated assess criteria for sbt dailysao2 90%) increase peep to max 20 identify possible acute lung injury identify respiratory failure causesacute lung injuryno injuryfail sbtacute

35、lung injury low tv (lung-protective) settings reduce tv to 6 ml/kg increase rr up to 35 to keep ph 7.2, paco2 50 adjust peep to keep fio2 60%sao2 90%sao2 90% continue lung-protective ventilation until: pao2/fio2 300 criteria met for sbtpersistently fail sbt consider tracheostomy resume daily sbts wi

36、th cpap or tracheostomy collarpass sbtairway stableextubateintubated 2 wks consider psv wean (gradual reduction of pressure support) consider gradual increases in sbt duration until endurance improvesprolonged ventilator dependencepass sbtpass sbtairway stablemodified from sena et al, acs surgery: p

37、rinciples and practice (2005).mechanical ventilation for nursingmelissa dearing, bs, rrt-nps, rcpassociate professor of respiratory carecurtis shelley, bs, rrt-nps, rcprespiratory educator hermann childrens hospital indications for mechanical ventilation airway compromise airway patency is in doubt

38、or patient may be at risk of losing patencyindications for mechanical ventilationneed to protect the airwayfor some reason the patients ability to sneeze, gag or cough has been dulled and aspiration is possible.contraindications for an artificial airwaywhen a pts desire to not be resuscitated has be

39、en expressed and is documented in the pts chartestablishing an artificial airway adult female 8.0 adult male 9.0miller vs. macintosh blades intubation procedurecheck and assemble equipment:oxygen flowmeter and o2 tubingsuction apparatus and tubingsuction catheter or yankauerambu bag and masklaryngos

40、cope with assorted blades3 sizes of et tubesstyletstethoscopetapesyringemagill forcepstowels for positioningintubation procedureposition your patient into the sniffing position intubation procedurepreoxygenate with 100% oxygen to provide apneic or distressed patient with reserve while attempting to

41、intubate.do not allow more than 30 seconds to any intubation attempt.if intubation is unsuccessful, ventilate with 100% oxygen for 3-5 minutes before a reattempt. intubation procedure insert laryngoscope intubation procedure intubation procedure after displacing the epiglottis insert the ett. the de

42、pth of the tube for a male patient on average is 21-23 cm at teeththe depth of the tube on average for a female patient is 19-21 at teeth.intubation procedure confirm tube position:by auscultation of the chestbilateral chest risetube location at teethco2 detector (esophageal detection device)intubat

43、ion procedure stabilize the ett intubation procedure video on intubation:http:/ ventilatorsdifferent types of ventilators available:will depend on you place of employmentmechanical ventilatorsmechanical ventilatorsmechanical ventilatorsmechanical ventilatorsmechanical ventilatorshigh frequency mecha

44、nical ventilatorventilator settings terminology a/c: assist-controlimv: intermittent mandatory ventilationsimv: synchronized intermittent mandatory ventilationbi-level/biphasic: non-inversed pressure ventilation with pressure support (consists of 2 levels of pressure)ventilator settings terminology

45、(cont) prvc: pressure regulated volume control peep: positive end expiratory pressurecpap: continuous positive airway pressurepsv: pressure support ventilationnippv: non-invasive positive pressure ventilationvolume vs. pressure ventilation volume ventilation: volume is constant and pressure will var

46、y with patients lung compliance.pressure ventilation: pressure is constant and volume will vary with patients lung compliance. modes of ventilationcontrol mode delivers pre-set volumes at a pre-set rate and a pre-set flow rate.the patient cannot generate spontaneous breaths, volumes, or flow rates i

47、n this mode. control mode assist/control mode delivers pre-set volumes at a pre-set rate and a pre-set flow rate.the patient cannot generate spontaneous volumes, or flow rates in this mode. each patient generated respiratory effort over and above the set rate are delivered at the set volume and flow

48、 rate. a/c cont.delivers a pre-set number of breaths at a set volume and flow rate.allows the patient to generate spontaneous breaths, volumes, and flow rates between the set breaths.detects a patients spontaneous breath attempt and doesnt initiate a ventilatory breath prevents breath stackingsychro

49、nized intermittent mandatory ventilation (simv):simv cont.pressure regulated volume control (prvc): this is a volume targeted, pressure limited mode. (available in simv or ac) each breath is delivered at a set volume with a variable flow rate and an absolute pressure limit. the vent delivers this pr

50、e-set volume at the lowest required peak pressure and adjust with each breath.prvcpositive end expiratory pressure (peep): this is not a specific mode, but is rather an adjunct to any of the vent modes. peep is the amount of pressure remaining in the lung at the end of the expiratory phase. utilized

51、 to keep otherwise collapsing lung units open while hopefully also improving oxygenation. peep cont.peep is the amount of pressure remaining in the lung at the end of the expiratory phase.pressure above zerodemonstration of peep http:/ positive airway pressure (cpap): this is a mode and simply means

52、 that a pre-set pressure is present in the circuit and lungs throughout both the inspiratory and expiratory phases of the breath. cpap serves to keep alveoli from collapsing, resulting in better oxygenation and less wob. the cpap mode is very commonly used as a mode to evaluate the patients readines

53、s for extubation.high frequency ventilationcomparison of hfov& conventional ventilationdifferencescmvhfovrates0 - 150180 - 900tidal volume4 - 20 ml/kg0.1 - 3 ml/kgalveolar press0 - 50 cmh2o0.1 - 5 cmh2oend exp volumelownormalizedgas flowlowhighoxygenation oxygenation is primarily controlled by the mean airway pressure (paw) and the fio2. mean airway pressure is a constant pressure used to inflate the lung and hold the alveoli open. since the paw is constant, it reduces the injury that results from cycling the lung open for each breathvideo on hfovht