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| LETTER TO EDITOR |
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| Year : 2015 | Volume
: 2
| Issue : 2 | Page : 172 |
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Does the monitor always show actual reading?
Monish S Raut, Arun Maheshwari
Department of Cardiac Anesthesia, Dharam Vira Heart Center, Sir Ganga Ram Hospital, New Delhi, India
| Date of Web Publication | 16-Mar-2015 |
Correspondence Address:
Monish S Raut
Department of Cardiac Anesthesia, Dharam Vira Heart Center, Sir Ganga Ram Hospital, New Delhi
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2348-3334.153269
How to cite this article:
Raut MS, Maheshwari A. Does the monitor always show actual reading?. CHRISMED J Health Res 2015;2:172 |
Sir,
A 58-year-old male patient operated for coronary artery bypass grafting surgery was extubated uneventfully. As the patient was breathing spontaneously, his central venous pressure (CVP) waveform was swinging vertically. CVP number shown on the monitor was 10 mm Hg [Figure 1]. Ideally CVP should be measured at base of 'A' wave in end expiration. [1] During spontaneous inspiration, venous return on right side of heart increases and CVP falls as intrathoracic pressure lowers in normally compliant heart. During spontaneous expiration, venous return decreases on right side. This will raise CVP as intrathoracic pressure increases. Hence during spontaneous breathing, CVP waveform goes down in inspiration and it goes up in expiration. In the present case, CVP waveform marked with arrow is in end expiration. Reading at the base of 'A' wave in end expiration will give actual CVP number which would be 15 mm Hg markedly different from that shown on the monitor [Figure 1]. Monitoring patient's vitals is important for the management. However, numbers displayed on the monitor screen can be misleading. Management based upon numbers can adversely affect patient. In the present case, volume loading of the patient based on low CVP value on monitor can make the patient fluid overloaded whereas patient's actual CVP is already on higher side based upon waveform. Hence, it is imperative to look for the physiology before considering the number displayed on the monitor. | Figure 1: CVP waveform, arrow marked at end expiration corresponds to 15 mmHg
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| References | |  |
| 1. | Mark JB. Central venous pressure monitoring: Clinical insights beyond the numbers. J Cardiothorac Vasc Anesth 1991;5:163-73.  |
[Figure 1]
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