LETTERS TO THE EDITOR
122
REFERENCES
1. Sarin CI, Yalav E, Clement ment of left atria1 pressure 25:185-189,197O
AJ: The necessity of measureafter cardiac valve surgery. Thorax
Ann Thorac
2. Parr GVS, Blackstone GH, Kirklin JW: Cardiac performance and mortality early after intracardiac surgery in infants and young children.
Circulation
3. Gold JP, Jones RA. Lang P, et al: Transthoracic intracardiac monitoring lines in pediatric surgical cases: A ten years experience.
Surg 42:185-191,1986
4. McNicholas
KW, Niguidula
of left atrial monitoring
51:867-874,1975
Phlebotomy
and Cardiac
Output
NF: A technique
line. Ann Thorac
for placement
Surg35:568-569.
1983
Measurement
To the Editor: With reference to the article entitled “Phlebotomy Via the Pulmonary Artery Catheter Introducer for Intraoperative Autotransfusion” by Casthely et al,’ it has become common practice in this hospital to perform phlebotomy of 1 unit of autologous blood in the postinduction pre-bypass period. Whereas this can be performed with relative ease from the Y-port of a 7F thermodilution pulmonary artery catheter inserted in the right internal jugular vein, this may interfere with cardiovascular monitoring. If phlebotomy and cardiac output (CO) measurements are performed simultaneously, we have noticed on a number of occasions some of the 10 mL injectate tracking back down the Y-port, thereby giving rise to inaccuracy in CO/C1 measurements in this period. This is demonstrated quite dramatically in the data obtained during anesthesia from a 47-year-old woman presenting for elective coronary artery bypass grafting (Table 1). CO measurements were made during phlebotomy and some injectate was noted tracking back down the Y-port. Therefore, phlebotomy was discontinued temporarily and a new set of measurements taken within 2 minutes of the first set. This sequence was repeated 6 minutes later with similar results. There was a 1.0 L/mm and 1.1 L/min difference, respectively, in the calculated CO during phlebotomy; all other cardiovascular parameters were stable. Therefore, we recommend that if the Y-port is being used for phlebotomy, it should be temporarily discontinued (by means of a three-way stopcock) during CO measurements. Brian Marsh, FFARCSI David Cooper, FCAnaes Royal Perth Hospital Perth, Australia
Table 1. Inaccurate Cardiac Output Values During Phlebotomy
Time
HR (beatslmin)
BP (mm Ml
58
106153
59
PAP (mm Hg)
PCWP (mm Hgl
co (Llminl
2517
4
3.5
116157
2618
6
2.5
87
149171
3219
6
3.6
80
148171
33/10
6
2.5
14:20 During phlebotomy 14:22 Phlebotomy stopped 14:28 During phlebotomy 14:29 Phlebotomy stopped
Abbreviations: HR. heart rate; BP, blood pressure; PAP, pulmonary arterial pressure; PCWP, pulmonary capillary wedge pressure; CO, cardiac output.
REFERENCE 1. Casthely autotransfusion.
AP, Yoganathan J Cardiothorac
T, Salem M, et al: Phlebotomy Vast Anesth 4:43-45, 1990
via the
pulmonary
artery
catheter
introducer
for
intraoperative
122
REFERENCES
1. Sarin CI, Yalav E, Clement ment of left atria1 pressure 25:185-189,197O
AJ: The necessity of measureafter cardiac valve surgery. Thorax
Ann Thorac
2. Parr GVS, Blackstone GH, Kirklin JW: Cardiac performance and mortality early after intracardiac surgery in infants and young children.
Circulation
3. Gold JP, Jones RA. Lang P, et al: Transthoracic intracardiac monitoring lines in pediatric surgical cases: A ten years experience.
Surg 42:185-191,1986
4. McNicholas
KW, Niguidula
of left atrial monitoring
51:867-874,1975
Phlebotomy
and Cardiac
Output
NF: A technique
line. Ann Thorac
for placement
Surg35:568-569.
1983
Measurement
To the Editor: With reference to the article entitled “Phlebotomy Via the Pulmonary Artery Catheter Introducer for Intraoperative Autotransfusion” by Casthely et al,’ it has become common practice in this hospital to perform phlebotomy of 1 unit of autologous blood in the postinduction pre-bypass period. Whereas this can be performed with relative ease from the Y-port of a 7F thermodilution pulmonary artery catheter inserted in the right internal jugular vein, this may interfere with cardiovascular monitoring. If phlebotomy and cardiac output (CO) measurements are performed simultaneously, we have noticed on a number of occasions some of the 10 mL injectate tracking back down the Y-port, thereby giving rise to inaccuracy in CO/C1 measurements in this period. This is demonstrated quite dramatically in the data obtained during anesthesia from a 47-year-old woman presenting for elective coronary artery bypass grafting (Table 1). CO measurements were made during phlebotomy and some injectate was noted tracking back down the Y-port. Therefore, phlebotomy was discontinued temporarily and a new set of measurements taken within 2 minutes of the first set. This sequence was repeated 6 minutes later with similar results. There was a 1.0 L/mm and 1.1 L/min difference, respectively, in the calculated CO during phlebotomy; all other cardiovascular parameters were stable. Therefore, we recommend that if the Y-port is being used for phlebotomy, it should be temporarily discontinued (by means of a three-way stopcock) during CO measurements. Brian Marsh, FFARCSI David Cooper, FCAnaes Royal Perth Hospital Perth, Australia
Table 1. Inaccurate Cardiac Output Values During Phlebotomy
Time
HR (beatslmin)
BP (mm Ml
58
106153
59
PAP (mm Hg)
PCWP (mm Hgl
co (Llminl
2517
4
3.5
116157
2618
6
2.5
87
149171
3219
6
3.6
80
148171
33/10
6
2.5
14:20 During phlebotomy 14:22 Phlebotomy stopped 14:28 During phlebotomy 14:29 Phlebotomy stopped
Abbreviations: HR. heart rate; BP, blood pressure; PAP, pulmonary arterial pressure; PCWP, pulmonary capillary wedge pressure; CO, cardiac output.
REFERENCE 1. Casthely autotransfusion.
AP, Yoganathan J Cardiothorac
T, Salem M, et al: Phlebotomy Vast Anesth 4:43-45, 1990
via the
pulmonary
artery
catheter
introducer
for
intraoperative
