The Many Disguises of PEEP: Case Presentations Bradley J. Phillips, MD Burn-Trauma-ICU Adults &...
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Transcript of The Many Disguises of PEEP: Case Presentations Bradley J. Phillips, MD Burn-Trauma-ICU Adults &...
The Many Disguises of PEEP:Case Presentations
Bradley J. Phillips, MD
Burn-Trauma-ICUAdults & Pediatrics
PEEP
Positive End Expiratory Pressure Equilibrium pressure reached at end of expiration is
some small amount of pressure greater than atmospheric
PEEP = 5 mmHg considered to be physiologic
Disquises of PEEP
• Improves O2
• Increases cardiac output
• Increases lung compliance
• Worsens O2
• Decreases cardiac output
• Barotrauma• Fluid retention• Intracranial HTN
• CO2 clearance
Gas Exchange
O2
PEEP I:E alterations Positioning
• * Prone/Lateral
Rate Tidal volume I:E alternations
Intubation Criteria
Airway protection RR > 35-40 breaths/min PaCO2 > 55 mmHg ( acute)
PaO2< 70 mmHg on 100% O2 nonrebreather
A-a gradient> 400 mmHg on 100% O2 FM High spinal injury, closed head injury, ARDS, metabolic
acidosis with clinical deterioration
Benefits of PEEP?
There is no evidence that routine use of PEEP is
beneficial in all patients!
Case #2CO2 Retention
67 yom s/p radical neck dissection for tumor of posterior pharynx
PMH: COPD - steroid x 3 yearsCAD s/p IWMI 8yrs ago
PSH: CABG x3 5 years ago
SH: Beer - 4-5/daySmoker - 1.5 ppd
Case #2
Uncomplicated procedure, admitted to ICU for mechanical ventilation
PE: elderly appearing, surgical wound on neck, JP x1old scar on sternum, S2 loud breath sound quietscaphoid abdomen
LAB: WBC 14.2, Hct 25%
CXR: Hyperinflated lung o/w clear
Case #2
Initial tx : ABX per ENT (clindamycin)Albuterol inhalerIV steroids
POD2 : ExtubatedTube feedings started
POD3: Dyspnea, RR 30/minCrackles at right base, wheezing bilaterallyABG:pH 7.21, PaCO2 74, PaO2 48 @ FiO2 0.6
Case #2
ABC’s - Intubated
CXR - right sided infiltrate in lower and apical fields
Diagnosis: ?
Initial vent setting: SIMV 12/TV 650ml/FiO2 1.0/Peep 5Agitated, BP 220/120, HR 120, RR 40Peak airway pressures 60 - 65 cmH2O
Diagnosis and tx: ?
Case #2
Sedated with midazolam (Versed) drip
1 hr later : unresponsiverapid breathing, out of phase with ventilatorPAP = 70 mmH2O
Therapy : ?
1 hr later: PAP 35 cm H2OFiO2 decreased to 0.6 with O2 sats 96%ABG: 7.36/50/94
Case #2
Evening: Desats 90%Wheezing in all fields, crackles r baseCXR: new left patchy infiltrateABG: 7.34/56/68 - Vent setting changed ???90mins: ABG PaCO2 decreased, PaO2 increased
3 hrs later: Desat 93%, no ABGVent setting changed ???ABG: 7.34/58/64Vent setting changed ???ABG: 7.30/62/63, PAP 50 mmH2O
Case #2
Vent changed - FiO2 1.0, PEEP 20 cm H2OABG 7.24/68/61
Vent changed- ??? ParameterBP 132/80 to 94/54Arterial sats 80’sCXR/EKG orderedDopamine startedABG 7.10/84/52VT - CPR started
Case #2
Trap: PEEP applied to the ventilatorauto-PEEP developed by increased RRResults: Difficulty with CO2 elimination
Trick: Limit PEEP and assess for auto-PEEPReduce RR Treat reversible component of COPD
Consider I:E manipulations
PEEP effects on pulmonary physiology and gas
exchange
PEEP effects on oxygenation frequently considered PEEP effects on ventilation often neglected Physiological dead space
• Anatomic dead space• Shunt factor• V/Q mismatch• Haldane effect
PEEP effects on pulmonary physiology and gas
exchange
Factors affected by acute lung injury and chronic airflow obstruction
PEEP low levels (5-10 cm)• reduces dead space by reducing shunt
PEEP high levels (=>15)• variable and unpredictable
• V/Q mismatched • Ventilate high V/Q regions
• Reduce CO2 elimination
• Etiology ? decreased cardiac output or directcompression of alveolar capillaries
PEEP effects on pulmonary physiology and gas
exchange
High PEEP
Impaired CO2 Removal
Haldene effect
Impaired Oxygenation
Increased anatomic dead space
Alterations of V/Q
Alterations of V/Q
(Direct compression)
Case #1
75 yof s/p colostomy for perforated diverticulum
PMH: Asthma - inhalers Meds: AlbuterolDM - 10 years Atrovent
PSH: none
SH: no EtOH or Tobacco use
Case #1Hypotension
Transferred to ICU for sepsis and ventilator management
PE: ill appearing, pale, obese female mild dyspneaT 39 HR 120, SBP 90, RR 30, sats 92%, wt 80kg
Lungs: few wheezes bilateralCV: normal S1,S2Abd: distended, open skin, mild tenderness
Ext: mild edema, slight mottled distally
LABS: WBC 18K, Hct 27 Na 131, K 3.1, Bun 15, Cr 1.6, BS 220
Case #1
Initial Tx (ABC’s) : Intubate Vent AC 12/800/80%/PEEP5
NPO/IVF/NGT/ABXInhalers tx.Dopamine qttReplete K
After intubation: SBP 80’s briefly then 95ABG: 7.32/48/70/96%
Case #1
Vent changes: Increased vent rateABG: 7.36/42/65/94%
2 hrs later: Agitated, RR 25, sats 88%ABG 7.46/32/58
? Vent changes or therapeutic interventions
Case #1
Vent changes: Increased PEEP 10ABG 7.50/28/60/90%
? Vent changes or therapeutic maneuvers?
4 hrs post op : VS: HR 130’s, BP 85/60, RR30, sats 85%
What’s happening???
PEEP effects on cardiovascular output
Positive pressure ventilation • increased intrathoraci pressure• reduced venous return• decreased Cardiac output (CO)• fluid resuscitation prior to intubation
PEEP effects on cardiovascular output
High PEEP• Increased intrathoracic pressure• Barotrauma - tension PTX
Auto-PEEP (Hyperinflation)• Increased FRC with or without PEEP set• Insufficient expiratory time to expel TV• Diseases @ risk
• Emphysema - loss of elastic recoil • Asthma - increased airway resistance
Auto-PEEP
Measurement technique• Occlusion of expiratory port• Immediately before delivery of next breath• Any increase in airway pressure above end-
expiratory level represents auto-PEEP• Timing is important, too early and falsely elevated
estimate
Auto-PEEP
Treat underlying disease• Bronchospasm• Sepsis
Sedation and paralytics Adjust ventilator mode Consider “permissive hypercapnia”
Case #3Difficult Oxygenation
54 yom s/partial gastrectomy for adenocarcinoma
PMH: HTN Meds: CardiazemGERD Axid
PSH: RIH repairLipoma excision
SH: ETOH: 1/2 case qdSmoker 1 ppd
CASE #3
POD 0: Admitted to ICUUnremarkable eventsExtubated POD1 and transferred to floor
POD 3: Acute onset of dyspnea, RR25Diaphoretic, mild cyanosis, tachycardiaTransferred to ICU
Initial work-up: ????
Case #3
Initial workup: EKG - normalCXR - RLL infilrateABG 7.50/32/50IntubatedVent SIMV 16/750 ml/100%/PS5
1 hr. later: Sedated, RR 16, SBP 110, HR 110ABG 7.38/42/56/86%
?? Vent changes ??
Case #3
Vent changes: PEEP 5.0 added, no changePEEP 10, drop in COABG 7.32/50/58/88%
What is his diagnosis?
What interventions are available to improve oxgenation?
Unilateral Lung Injury
Increased PEEP• Paradoxically increased shunting• Increased V/Q ratio
• increased in overdistended lung units• increased in ratio of deadspace to tidal volume
Therapeutics for Oxygenation
Unilateral• PEEP appropriately• Sedation• Paralytics
• reduce chest wall tone
• reduces O2 demand
• Lateral position• Differential lung
ventilation (DVL)
Bilateral (ARDS) Same as Unilateral except:
• Prone positioning• No indication for DVL• Consider Jet ventilation• Consider extracorporal
membrane oxygenation (ECMO)
Questions…..?