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Table of Contents
Year : 2022  |  Volume : 25  |  Issue : 3  |  Page : 374-375
Endoscopic saphenous vein harvest: Severe hypercarbia

Department of CTVS Anaesthesiology and Critical Care, Aster Medcity, Kochi, Kerala, India

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Date of Submission17-Feb-2022
Date of Acceptance22-Feb-2022
Date of Web Publication05-Jul-2022

How to cite this article:
Menon LP, Nair SG, Kurian GV, Abraham J. Endoscopic saphenous vein harvest: Severe hypercarbia. Ann Card Anaesth 2022;25:374-5

How to cite this URL:
Menon LP, Nair SG, Kurian GV, Abraham J. Endoscopic saphenous vein harvest: Severe hypercarbia. Ann Card Anaesth [serial online] 2022 [cited 2022 Oct 4];25:374-5. Available from:

To the Editor,

Although arterial conduits are favoured during coronary artery bypass grafting (CABG), a variable number of venous grafts are used in all patients undergoing the procedure. Endoscopic vein harvesting of the great saphenous vein has multiple advantages over the traditional open vein harvesting technique.

A 40-year-old male patient with critical left main involvement and triple vessel disease was uneventfully anaesthetised for CABG surgery using standard anaesthetic techniques. A baseline arterial blood gas before surgical incision revealed normal values as follows: pH 7.34; partial pressure of carbon dioxide (PaCO2) 40 mmHg; partial pressure of oxygen (PaO2) 152 mmHg (fraction of inspired oxygen (FiO2) 0.35); bicarbonate level 23.7 mmol/L; potassium 4.3 mmol/L.

Endoscopic vessel harvesting (EVH) (Vasoview 7xB, Wayne, NJ, USA) was done through a transverse incision on the medial aspect of the left knee. CO2 insufflation was initiated at a flow of 2 L/min, resulting in constant pressure of 10 mmHg. The physician-assistant who was harvesting the vein incidentally noted increased bleeding in the field.

Ten minutes after the EVH incision, the end tidal CO2 (ETCO2) began to rise progressively and peaked at 88 mmol/L [Figure 1]. Immediate response included checking the ventilation and suctioning the patient. An arterial blood gas (ABG) demonstrated severe respiratory acidosis without impairment of oxygenation (pH 7.13; PaCO2 87.9; PaO2 201 (FiO21); single breath counting (SBC) 29.2 mmol/L). The temperature of the patient remained normal. Transesophageal echocardiogram (TEE) depicted no evidence of air in the right atrium (RA) or in the inferior vena cava. Similarly, there was no evidence of rebreathing or hypermetabolic state such as malignant hyperthermia. A repeat arterial blood gas after 30 minutes exhibited a similar picture. Hand ventilation did not result in any significant change in the PaCO2 levels. The heart rate increased by 12 beats/min. Body temperature, heart rhythm, and blood pressure remained unchanged.
Figure 1: Monitor displaying high ETCO2. The high airway pressures may be attributed to large tidal volume used during hand ventilation and also when the VT was increased to 550 mL in an attempt to reduce the ETCO2

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At this point, there was a suspicion that the CO2 being used for the EVH could contribute to the high ETCO2. The surgeons were instructed to terminate the EVH. Immediately after the cessation of CO2 insufflation, there was a remarkable improvement in the ETCO2. The surgeons abandoned EVH and an open technique was used to harvest the remaining vein. Soon, the ETCO2 concentration decreased to pre-insufflation levels, and normal ventilation could be resumed. The patient then underwent 3-vessel coronary artery bypass graft surgery without further complications.

A sudden rise in ETCO2 during surgery can have catastrophic consequences on the patient. Routine causes like ventilation, hyperthermia, or any hyper metabolic state and airway issues are to be immediately ruled out. Hypercarbia during EVH is not well known although there are a few reported cases in the literature.[1–3] Liu et al.[3] in a study of 405 patients undergoing EVH for CABG or femoro-popliteal grafting exhibited mild, moderate, and massive amounts of CO2 embolism in 13.1%, 3.5%, and 0.5% of patients. The author suggested that for detection of CO2 embolism during EVH, the inferior vena cava should be inspected for air bubbles.

Carbon dioxide can enter the systemic veins either by venous absorption of the gas or by the entry of CO2 through the open end of injured or cut veins.[3] In moderate and massive CO2 embolism, the later mechanism has a predominant role. Hypercarbia is also influenced by the tunnel pressure or the type of system being used for EVH.[4],[5] Higher tunnel pressures and closed EVH systems (which were used in this case) are associated with a higher incidence of hypercarbia.

In summary, we described a case of significant hypercarbia resulting from increased absorption of CO2 during EVH. Close monitoring of ETCO2 levels during this process is encouraged for early detection and management of hypercarbia.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Maslow AD, Schwartz CS, Bert A, Hurlburt P, Gough J, Stearns G, et al. Endovascular vein harvest: Systemic carbon dioxide absorption. J Cardiothorac Vasc Anesth 2006;20:347-52.  Back to cited text no. 1
Martineau A, Arcand G, Couture P, Babin D, Perreault LP, Denault A. Transesophageal echocardiographic diagnosis of carbon dioxide embolism during minimally invasive saphenous vein harvesting and treatment with inhaled epoprostenol. Anesth Analg 2004;96:962-4.  Back to cited text no. 2
Liu TY, Chiu KM, Wang MJ, Chu SH. Carbondioxide embolism during endoscopic saphenous vein harvesting in coronary artery bypass grafting. J Cardiothorac Vasc Surg 2003;126:2011-5.  Back to cited text no. 3
Potapov EV, Buz S, Hetzer R. CO2 embolism during minimally invasive vein harvesting. Eur J Cardiothorac Surg 2007;31:944-5.  Back to cited text no. 4
Zingaro C, Pierri MD, Massi F, Matteucci ML, Capestro F, D'Alfonso A, et al. Absorption of carbio dioxide during endoscopic vein harvest. Interact Cardiovasc Thorac Surg 2012;15:661-4.  Back to cited text no. 5

Correspondence Address:
Lakshmi P Menon
SF1, Neelanghat Appartments, St. Benedict's First Cross Road, Ernalulam North, Kochi, Kerala - 682018
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aca.aca_39_22

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  [Figure 1]