Sorry for my misinterpretation of your question, Rick. I work in a hospital where house staff and others often order a peripheral vbg solely for venous saturation, erroneously using the result to guide resuscitation instead of obtaining central or mixed venous saturation.
There's a useful summary of the relative values of VBGs vs ABGs in UptoDate - "Venous blood gases and other alternatives to arterial blood gases" - with a caution regarding PvCO2 in shock states. The difference between PvCO2 and PaCO2 widens with severity of shock and can be substantial. An elevated PvCO2 may therefore indicate shock, hypercarbia, or some combination thereof. Mixed forms and subtle degrees of shock can be difficult to recognize at the bedside. The authors also caution: "Importantly, sufficient variability between arterial and venous blood gas values may exist such that periodic correlation between arterial and venous blood gas values is always prudent." Peripheral venous O2 saturation cannot replace central or mixed venous saturation as a guide to resuscitation. On one hand, rapid peripheral VBG analysis may spare a patient an arterial puncture to assess pH, pCO2, and HCO3; on the other hand, interpretation of that peripheral VBG may be more complicated than realized. I'm unaware of studies addressing the relative accuracies of interpretation, effects on outcome, value as an addition to screening panels, or prognostic implications of peripheral VBGs in particular. Arguably, neither ABGs nor VBGs are necessary to manage many patients with sepsis. Look forward to seeing other opinions. Thanks Ron On Nov 30, 2015 9:14 PM, "Rutherford, Richard" < [email protected]> wrote: > > Hi Doctor Elkin, > > > Thanks for your response. The advocates of VBG at my hospital are not proposing to use peripheral blood to follow SVO2 but rather to have access to peripheral venous pH, HCO3, pCO2 and electrolytes in five minutes instead of an hour. They feel it could lead to earlier recognition of critical illness especially in mixed situations (hypercarbia respiratory failure AND septic shock for example). At our hospital it would not add cost or resource time, and it makes some intuitive sense to me but I am unaware of any emergency departments using this strategy. I appreciate your thoughts. > > > Rick > > > Richard Rutherford, M.D. > Quality Medical Director, Ventura County Medical Center > 3291 Loma Vista Road, Ventura, CA 93003 > (805) 665-8234 (cell) > (805) 652-6096 (office) > > > ________________________________ > From: Ron Elkin <[email protected]> > Sent: Monday, November 30, 2015 7:10 PM > To: Rutherford, Richard > Cc: [email protected] > Subject: Re: [Sepsis Groups] VBG for screening > > > Hi Richard, > > VBG must be obtained from central access point - junction of RA and SVC or from pulmonary artery - to permit interpretation. Most patients lack central access at time they are screened. VBG from a peripheral vein is of little or no value. > Central saturation and CVP before resuscitation (forgive me for this blasphemy) - if readily available from a dialysis catheter, PICC or port - may help guide the resuscitation effort, or at least make you think twice about your patient. > > Hope this helps. > > Ron Elkin MD > California Pacific Medical Center > San Francisco > > On Nov 30, 2015 2:21 PM, "Rutherford, Richard" < [email protected]> wrote: >> >> Hello all, >> >> >> My hospital is considering expanding our sepsis screening so that a VBG+Lactate is checked for every patient with a positive sepsis screen (instead of lactate alone). Have any other hospitals done this? Does anyone have a second set of criteria for sicker patients for whom VBG is ordered? >> >> >> Thanks, >> >> >> Richard Rutherford, M.D. >> Quality Medical Director, Ventura County Medical Center >> 3291 Loma Vista Road, Ventura, CA 93003 >> (805) 665-8234 (cell) >> (805) 652-6096 (office) >> >> _______________________________________________ >> Sepsisgroups mailing list >> [email protected] >> http://lists.sepsisgroups.org/listinfo.cgi/sepsisgroups-sepsisgroups.org >>
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