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HypotensionHypovolemic Cardiogenic Vasogenic

Low CVP High CVP Low CVP

Low CI Low CI High CI

High SVR High SVR Low SVR

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PhysiologiceffectsofCO2pneumoperitoneum

CO2suppressescombustionandisrapidlyabsorbedandthereforeisthepreferredgasforlaparoscopy.

ThephysiologiceffectsofCO2pneumoperitoneumcanbedividedintotwoareas:

(1)gas-specificeffects.

(2)pressure-specificeffects.

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PhysiologiceffectsofCO2pneumoperitoneum

CO2israpidlyabsorbedacrosstheperitonealmembraneintothecirculation.Inthecirculation,CO2createsa

respiratoryacidosisbythegenerationofcarbonicacid.

Bodybuffers,thelargestreserveofwhichliesinbone,absorbCO2(upto120L)andminimizethedevelopmentofhypercarbiaorrespiratoryacidosisduringbriefendoscopicprocedures.

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PhysiologiceffectsofCO2pneumoperitoneum

Oncethebodybuffersaresaturated,respiratoryacidosisdevelopsrapidly,andtherespiratorysystemassumesthe

burdenofkeepingupwiththeabsorptionofCO2anditsreleasefromthesebuffers.

Anesthesiologistincreasestheventilatoryrateorvitalcapacityontheventilator.Iftherespiratoryraterequiredexceeds20breathsperminutetheremaybelessefficient

gasexchangeandincreasinghypercarbia.

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PhysiologiceffectsofCO2pneumoperitoneum

Ifvitalcapacityisincreasedsubstantiallythereisagreateropportunityforbarotraumaandgreaterrespiratory-

motion-induceddisruptionoftheupperabdominaloperativefield.

moresevererespiratoryacidosisleadingtocardiacarrhythmiashasbeenreported.

Hypercarbiaalsocausestachycardiaandincreasedsystemicvascularresistance,whichelevatesbloodpressureandincreasesmyocardialoxygendemand.

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PhysiologiceffectsofCO2pneumoperitoneum

Pressureeffectsofthepneumoperitoneumoncardiovascularphysiology.

Inthehypovolemicindividual,excessivepressureontheinferiorvenacavaandareverseTrendelenburgpositionwith

lossoflower-extremitymuscletonemaycausedecreasedvenousreturnandcardiacoutput.

Themostcommonarrhythmiacreatedbylaparoscopyisbradycardia.Arapidstretchoftheperitonealmembrane

oftencausesavagovagalresponsewithbradycardiaand,occasionally,hypotension.

Managementofthiseventisbydesufflation,atropine,andadequatevolumereplacement.

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PhysiologiceffectsofCO2pneumoperitoneum

Increasedintra-abdominalpressurecompressingtheinferiorvenacavadiminishedvenousreturnfromthelowerextremities.

Venousengorgementanddecreasedvenousreturnpromotevenousthrombosis,maypromotePE.

UseSCD,Lovenox. Thedirecteffectofthepneumoperitoneumonincreasing

intrathoracicpressureincreasespeakinspiratorypressure,pressureacrossthechestwall,andalsothelikelihoodofbarotrauma.

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GasemboliduringLaparoscopy

Gasemboliarerarebutseriouscomplicationsoflaparoscopicsurgery. Theyshouldbesuspectedifhypotensiondevelopsduringinsufflation. Thetreatmentofgasembolismistoplacethepatientinaleftlateral

decubituspositionwiththeheaddowntotrapthegasintheapexoftherightventricle.

Centralvenouscatheterthencanbeusedtoaspiratethegasoutoftherightventricle.

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QASwanganzcathina70kgmalewasplacedthroughtheLeftsubclavianveinandawedgepressureisobtained.The

approximatedistanceintothept.shouldbe?

A. 45cmB.

50cm

C. 55cmD. 60cm

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Q-ConditionsnecessaryforPApressuretoequalL.atrialpressureincludeallofthe

followingexcept

A. Highlevelsofpositiveend-expiratorypressurearebeingdelivered

B. PApressureisgreaterthanalveolarpressureC. Pulmonaryvenouspressureisgreaterthanalveolar

pressure

D. PAcathiswedged.

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Q-Theoxyhemoglobindissociation

curveisshiftedtotheLeftby:

A. DecreasebloodpHB. Increasederythrocyte2,3-diphosphoglycerate(DPG)

concentration

C. IncreasedbodytempD. MethemoglobinemiaE. Carboxyhemoglobinemia

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