RES 241 CASE STUDIES Q AND
ANSWERS
Anbualert,buanxiousbu25-year-
oldbuwomanbupresentsbuinbuthebuemergencybudepartmentbu(ED)bucomplainingbuof
chills,bufever,buandbushortnessbuofbubreath.buAnbuarterialbubloodbugasbuisbudrawnbuonburoom
buairbuwithbuthese
results:
pHbu7.45
Paco2bu32bummbuHg
Pao2bu50bummbuHg
HCO3−bu23bumEq/L
Interpretbuthisbubloodbugas.
WhatbuisbuthebuA-abugradient?
Whatbutypebuofburespiratorybufailurebuisbupresent?
Whatbudobuyouburecommendbuforbuinitialburespiratorybutreatment?bu-buanswer--
acuteburespiratorybualkalosisbuwithbuhypoxemiabu(moderate)
PAO2bu=bu(760bu-bu47)buxbu0.21bu-bu(32bu÷bu0.8)bu=bu150bu-bu40bu=bu110bu(PAO2)buP(A-
a)O2bu=bu110bu-bu50bu=bu60bummbuHg
typebuIbuorbuhypoxemicburespiratorybufailure
Thebutextbookburecommendsbuadministeringbu100%buoxygenbutobuhelpbudifferentiatebumis
matchbufrombushunting.bu(Ibudon'tbuthinkbuthisbuisbuabucommonbupractice,bubutbuthere'sbunobu
doubtbuthebupatientbuneedsbuoxygen!)buYoubuwouldbuprobablybustartbuherbuonbuabucannulabu
atbu4butobu6buLbudependingbuonbuherbuclinicalbupresentation
Abu27-year-
oldbuisbubroughtbutobuthebuEDbubybuparamedicsbufollowingbuabudrugbuoverdose.buThebupatie
ntbuis
obtunded.buBloodbugasesbuarebudrawnbuonburoombuair:
pHbu7.24
Paco2bu60bummbuHg
Pao2bu65bummbuHg
HCO3−bu26bumEq/L
Interpretbuthisbubloodbugas.
WhatbuisbuthebuA-abugradient?
Whatbutypebuofburespiratorybufailurebuisbupresent?
Whatbuisbuthebuappropriatebuinitialburespiratorybutreatmentbuinbuthisbucase?bu-buanswer--
acuteburespiratorybuacidosisbuwithbuhypoxemiabu(mild)
PAO2bu=bu(760-47)buxbu0.21bu-bu(60bu÷bu0.8)bu=bu150-75bu=bu75bummbuHg.buP(A-
a)O2bu=bu75bu-bu65bu=bu10bummbuHg
typebuIIbuorbuhypercapnicburespiratorybufailure
Oxygenbutherapybuisbunotbuthebuissuebuinbuthisbucase.buThebupatientbuisbuhypoventilating,bua
ndbuthisbuisbuthebucausebuofbuthebuhypoxemia.buIntubationbuandbumechanicalbuventilationbu
arebuthebumostbulikelybuchoicesbuofbutreatment.
, Anbualertbu56-year-
oldbumanbuwithbuabuhistorybuofbuCOPDbupresentsbuinbuthebuEDbucomplainingbuofbudyspnea,b
uwhich
hasbuworsenedbuoverbuthebulastbufewbudays.buAbubloodbugasbuisbudrawnbuonburoombuair:
pHbu7.26
Paco2bu70bummbuHg
Pao2bu50bummbuHg
HCO3−bu32bumEq/L
Interpretbuthisbubloodbugas.
WhatbuisbuthebuA-abugradient?
Whatbutypebuofburespiratorybufailurebuisbupresent?
Whatbuinitialburespiratorybutreatmentsbuarebuindicated?buWhatbuarebuwebutryingbutobuavoid?
bu-buanswer--
partiallybucompensatedburespiratorybuacidosisbuwithbuhypoxemiabu(moderate)
PAO2bu=bu(76bu-bu47)buxbu0.21bu-bu(70bu÷bu0.8)bu=bu150bu-bu88bu=bu62bummbuHgbuP(A-
a)O2bu=bu62bu-bu50bu=bu12bummbuHg
Thisbupatientbualsobuhasbuhypercapnicburespiratorybufailure,bubutbuitbuisbuacuteburespiratory
bufailurebusuperimposedbuonbuchronicburespiratorybufailure.
ThebugoalbuforbuthisbupatientbuisbutobunormalizebuthebupHbuwhilebuavoidingbumechanicalbuve
ntilation.buBronchodilatorsbuwouldbubebuabusimplebustartingbupoint.buConsiderbubronchialbu
hygienebutechniques.buHebualsobuneedsbuabusmallbuamountbuofbuoxygen,buwithbuthebugoalbut
obuincreasebuthebuSaO2butobu90%.bu2buLbuviabucannulabuorbu28%bubybuAEM.
AnbuRTbuisbuaskedbutobuevaluatebuabulethargicbu50-year-
oldbuwomanbuwhobuisbuinburespiratorybudistressbufollowingbuabdominalbusurgery.buShebuisbu
breathingbuspontaneously,buonbuabu50%buair-
entrainmentbumask,buatbu32bubreathsbuperbuminute.buABGburesultsbushow
pHbu7.28
Paco2bu55bummbuHg
Pao2bu60bummbuHg
HCO3−bu26bumEq/Lbu-buanswer--Providebuintubationbuandbumechanicalbuventilation.
Anbualert,buanxiousbu60-year-
oldbumanbuwithbuabuhistorybuofbuCHFbupresentsbuinbuthebuEDbuwithburespiratorybudistress.buA
uscultationburevealsbubilateralbuinspiratorybucrackles.buHebuhasbuperipheralbuedema.buAB
Gburesultsbudrawnbuonbuabupartialburebreathingbumaskbushow
pHbu7.45
Paco2bu35bummbuHg
Pao2bu40bummbuHg
HCO3bu−bu23bumEq/Lbu-buanswer--AdministerbuoxygenbutherapybuviabuCPAP.
Abumanbuisbubeingbumechanicallybuventilatedbuimmediatelybuafterbusurgerybuforbuabuclosedb
uheadbuinjury.buSettingsbuare:
Tidalbuvolumebu700buml
Ratebu10
ModebuAC
Fio2bu0.40
PEEPbu0
ABGsbushow:
pHbu7.37
ANSWERS
Anbualert,buanxiousbu25-year-
oldbuwomanbupresentsbuinbuthebuemergencybudepartmentbu(ED)bucomplainingbuof
chills,bufever,buandbushortnessbuofbubreath.buAnbuarterialbubloodbugasbuisbudrawnbuonburoom
buairbuwithbuthese
results:
pHbu7.45
Paco2bu32bummbuHg
Pao2bu50bummbuHg
HCO3−bu23bumEq/L
Interpretbuthisbubloodbugas.
WhatbuisbuthebuA-abugradient?
Whatbutypebuofburespiratorybufailurebuisbupresent?
Whatbudobuyouburecommendbuforbuinitialburespiratorybutreatment?bu-buanswer--
acuteburespiratorybualkalosisbuwithbuhypoxemiabu(moderate)
PAO2bu=bu(760bu-bu47)buxbu0.21bu-bu(32bu÷bu0.8)bu=bu150bu-bu40bu=bu110bu(PAO2)buP(A-
a)O2bu=bu110bu-bu50bu=bu60bummbuHg
typebuIbuorbuhypoxemicburespiratorybufailure
Thebutextbookburecommendsbuadministeringbu100%buoxygenbutobuhelpbudifferentiatebumis
matchbufrombushunting.bu(Ibudon'tbuthinkbuthisbuisbuabucommonbupractice,bubutbuthere'sbunobu
doubtbuthebupatientbuneedsbuoxygen!)buYoubuwouldbuprobablybustartbuherbuonbuabucannulabu
atbu4butobu6buLbudependingbuonbuherbuclinicalbupresentation
Abu27-year-
oldbuisbubroughtbutobuthebuEDbubybuparamedicsbufollowingbuabudrugbuoverdose.buThebupatie
ntbuis
obtunded.buBloodbugasesbuarebudrawnbuonburoombuair:
pHbu7.24
Paco2bu60bummbuHg
Pao2bu65bummbuHg
HCO3−bu26bumEq/L
Interpretbuthisbubloodbugas.
WhatbuisbuthebuA-abugradient?
Whatbutypebuofburespiratorybufailurebuisbupresent?
Whatbuisbuthebuappropriatebuinitialburespiratorybutreatmentbuinbuthisbucase?bu-buanswer--
acuteburespiratorybuacidosisbuwithbuhypoxemiabu(mild)
PAO2bu=bu(760-47)buxbu0.21bu-bu(60bu÷bu0.8)bu=bu150-75bu=bu75bummbuHg.buP(A-
a)O2bu=bu75bu-bu65bu=bu10bummbuHg
typebuIIbuorbuhypercapnicburespiratorybufailure
Oxygenbutherapybuisbunotbuthebuissuebuinbuthisbucase.buThebupatientbuisbuhypoventilating,bua
ndbuthisbuisbuthebucausebuofbuthebuhypoxemia.buIntubationbuandbumechanicalbuventilationbu
arebuthebumostbulikelybuchoicesbuofbutreatment.
, Anbualertbu56-year-
oldbumanbuwithbuabuhistorybuofbuCOPDbupresentsbuinbuthebuEDbucomplainingbuofbudyspnea,b
uwhich
hasbuworsenedbuoverbuthebulastbufewbudays.buAbubloodbugasbuisbudrawnbuonburoombuair:
pHbu7.26
Paco2bu70bummbuHg
Pao2bu50bummbuHg
HCO3−bu32bumEq/L
Interpretbuthisbubloodbugas.
WhatbuisbuthebuA-abugradient?
Whatbutypebuofburespiratorybufailurebuisbupresent?
Whatbuinitialburespiratorybutreatmentsbuarebuindicated?buWhatbuarebuwebutryingbutobuavoid?
bu-buanswer--
partiallybucompensatedburespiratorybuacidosisbuwithbuhypoxemiabu(moderate)
PAO2bu=bu(76bu-bu47)buxbu0.21bu-bu(70bu÷bu0.8)bu=bu150bu-bu88bu=bu62bummbuHgbuP(A-
a)O2bu=bu62bu-bu50bu=bu12bummbuHg
Thisbupatientbualsobuhasbuhypercapnicburespiratorybufailure,bubutbuitbuisbuacuteburespiratory
bufailurebusuperimposedbuonbuchronicburespiratorybufailure.
ThebugoalbuforbuthisbupatientbuisbutobunormalizebuthebupHbuwhilebuavoidingbumechanicalbuve
ntilation.buBronchodilatorsbuwouldbubebuabusimplebustartingbupoint.buConsiderbubronchialbu
hygienebutechniques.buHebualsobuneedsbuabusmallbuamountbuofbuoxygen,buwithbuthebugoalbut
obuincreasebuthebuSaO2butobu90%.bu2buLbuviabucannulabuorbu28%bubybuAEM.
AnbuRTbuisbuaskedbutobuevaluatebuabulethargicbu50-year-
oldbuwomanbuwhobuisbuinburespiratorybudistressbufollowingbuabdominalbusurgery.buShebuisbu
breathingbuspontaneously,buonbuabu50%buair-
entrainmentbumask,buatbu32bubreathsbuperbuminute.buABGburesultsbushow
pHbu7.28
Paco2bu55bummbuHg
Pao2bu60bummbuHg
HCO3−bu26bumEq/Lbu-buanswer--Providebuintubationbuandbumechanicalbuventilation.
Anbualert,buanxiousbu60-year-
oldbumanbuwithbuabuhistorybuofbuCHFbupresentsbuinbuthebuEDbuwithburespiratorybudistress.buA
uscultationburevealsbubilateralbuinspiratorybucrackles.buHebuhasbuperipheralbuedema.buAB
Gburesultsbudrawnbuonbuabupartialburebreathingbumaskbushow
pHbu7.45
Paco2bu35bummbuHg
Pao2bu40bummbuHg
HCO3bu−bu23bumEq/Lbu-buanswer--AdministerbuoxygenbutherapybuviabuCPAP.
Abumanbuisbubeingbumechanicallybuventilatedbuimmediatelybuafterbusurgerybuforbuabuclosedb
uheadbuinjury.buSettingsbuare:
Tidalbuvolumebu700buml
Ratebu10
ModebuAC
Fio2bu0.40
PEEPbu0
ABGsbushow:
pHbu7.37
