A method for mathematical arterialization of venous blood gas v-tac is an advanced software algorithm that converts venous blood gas, combined with an SpO2 measurement, to arterial blood gas values with great accuracy and precision. v-tac is about: Clinical and operational work-flow optimisation Improving patient satisfaction Bjarne Flou CEO, OBI Medical
v-tac drives optimisation of workflow in blood gas testing With arterialisation by v-tac, a VBG becomes a true substitute to ABG and CBG in multiple clinical applications Arterial Blood Gas (ABG) Gold standard But Hard to get Painful Capillary Blood Gas (CBG) Accepted substitute for many clinical applications But Complex technique Operator dependent Acid-Base & Blood gas values Electrolytes values Metabolic values Arterial Acid-Base & Blood gas values Electrolytes values Metabolic values Venous Blood Gas (VBG) Easy to get Electrolytes, metabolics OK But Not ideal screening tool ABG follow-up needed Poor indicator of Progression of illness Response to treatment 5 Trend towards using VBG where possible
What is v-tac? v-tac software algorithm Based on Siggaard-Andersen Blood Model Peripheral venous blood gas values (Adults age 18+) SpO2 ph pco 2 po 2 Hb so 2 (FMetHB) (FCOHb) From Pulse oximeter (Software application) Calculated arterial blood gas ph pco 2 po 2 * HCO 3 - BE pao 2 /FiO 2 Ratio* (so 2 ) 2,3 DPG to 2 tco 2 SBE, SBC, co-oximetry etc. available from the VBG *po2 >10 kpa reported as > 10 kpa Watch Prof. Dr. Stephen E. Rees present the principles of the v-tac methodon our Youtube channel: https://www.youtube.com/channel/ucqt2l5zpm_vv71uqh1vt3bw/videos 6
When can v-tac be used? Patients age 18+ All clinical indications Other indications: Peripheral is warm, red and dry; a pulse can be felt Capillary response is normal Can a stable oxygen sat (SpO2) at 75%* or above be measured? YES Can a peripheral venous sample be drawn? NO NO Indications of too poor circulation: Difficulty measuring SpO2 (on the arm used for the sample) The arm/peripheral is cold/blue Long stasis time for blood-sampling The patient develops catecholamines (or similar) YES Convert using the v-tac software Use alternative method, such as ABG 10 *Configurable, default = 80%
Typical Radiometer/v-TAC setup (Example from DK) v-tac printer next to ABL configured for v-tac ABL configuration: A sample type v-tac is configured on the ABL to identify and mark samples for arterialisation by v-tac When v-tac is selected, the SpO2 value shall be entered into a mandatory input field ABL operation In daily operation, when the venous blood sample has been taken and SpO2 measured, the v-tac button is selected and SpO2 entered The v-tac results are immediately sent to the printer (optinal) and/or sent to the LIS/EPR (optional) For additional information please request technical manual 20
v-tac printed report (A4) Print from BGA Print from v-tac v-tac calculated arterial values Selected venous results from BGA print is transferred to v-tac print Printer: For example A4 network laser printer (recommended) 38
v-tac results in LIS Example from North Denmark Regional Hospital (LABKA-II) Venous Results Calculated v-tac arterial results 39 v-tac results clearly marked v-tac according to nomenklatur defined by MEDCOM and following IUPAC standards
ph v-tac & ABG repeatability vs ABG v-tac Bias ±95% Limits of Agreement -0.001 ±0.03 v-tac vs ABG-1 (n=416, Pooled data) ABG-2 vs ABG-1 (n=73, Toftegaard, 2008) v-tac vs ABG-1 (n=416, Pooled data) ABG-2 vs ABG-1 (n=73, Toftegaard, 2008) Bias ±95% Limits of agreement (v-tac) Plots compare v-tac ph vs ABG-1 (black dots) withtoftegaard studying ABG-2 vs ABG-1 repeatability (red dots). Conclusion: v-tac ph repeatability is comparable to arterial repeatability 44
pco2 v-tac & ABG repeatability vs ABG v-tac Bias ±95% Limits of Agreement -0.043 ±0.53 kpa v-tac vs ABG-1 (n=416, Pooled data) ABG-2 vs ABG-1 (n=73, Toftegaard, 2008) v-tac vs ABG-1 (n=416, Pooled data) ABG-2 vs ABG-1 (n=73, Toftegaard, 2008) Bias ±95% Limits of agreement (v-tac) Plots compare v-tac pco2 vs ABG-1 (black dots) withtoftegaard studying ABG-2 vs ABG-1 repeatability (red dots). Conclusion: v-tac pco2 repeatability is comparable to arterial repeatability 45
po2 v-tac & ABG repeatability vs ABG Zoom area Plot explanation: v-tac vs ABG-1 (n=208, Pooled data) ABG-2 vs ABG-1 (n=192, Mallat et al., 2015) Mallat ±95% Limits of agreement ABG-2 vs ABG-1 (n=73, Toftegaard, 2008) Toftegaard ±95% Limits of agreement Zoom area Plots compare v-tac po2 vs ABG-1 (black dots) with two sources of arterial vs arterial repeatability: Mallat (green dots, studying ABG repeatability while minimizing pre-analytical and biological contributions) and Toftegaard (red dots). Conclusion: v-tac po2 repeatability is comparable to arterial repeatability for values of po2 up to 10 kpa 46 Notes: v-tac reports calculated po2 values between 0 to 10 kpa. If calculated po2 exceeds 10 kpa, v-tac reports po2 > 10 kpa Tygesen et al. Group-B excluded due to 10-15 minutes between v-tac and ABG
Venipuncture is easier and less paintful for the patient compared to arterial punctures ~330 Recent UK study show that: On a scale from 0 10, pain associated with arterial punctures score avg 4, while venipunctures score 1 To make 234 blood samples it takes approximately 330 arterial attempts, while the same can be done with approximately 260 venous attempts ~260 Source: McKeever et al. 2016, Using venous blood gas analysis in the assessment of COPD exacerbation: a prospekctive cohort study (REF635) 82
Thank you! More information: www.obimedical.com 94