Q: 68-year-old patient admitted with CHF. Now, with diuresis, the patient is clinically stable and ready for transfer to the floor. Patient's last CVP noted was 12. The patient's bed is raised to perform a portable chest x-ray. With elevation of the bed, CVP will? (select one)
A) Fall
B) Rise
C) No change
Answer: B
The CVP transducer and intravascular volume at the "zero" point act as a balance of fluids. If the transducer drops below zero (such as when the bed is elevated), CVP will rise. It's similar to a seesaw.
Bed up - CVP falsely down
Bed down - CVP falsely up
#hemodynamics
References:
1. Zhou J, Zuo X, Liu S, Chu M, Tian Y. [Discussion on the zero-calibration and the zero line in the measurement of central venous pressure and invasive arterial blood pressure]. Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2023 Mar;35(3):316-320. Chinese. doi: 10.3760/cma.j.cn121430-20220926-00862. PMID: 36916347.
2. Lloyd-Donald P, Fujino M, Waldman B, Miles LF. Measurement and interpretation of central venous pressure: a narrative review. Anaesthesia. 2025 Sep;80(9):1093-1102. doi: 10.1111/anae.16633. Epub 2025 Jun 3. PMID: 40457939; PMCID: PMC12351226.
3. Figg KK, Nemergut EC. Error in central venous pressure measurement. Anesth Analg. 2009 Apr;108(4):1209-11. doi: 10.1213/ane.0b013e318196482c. PMID: 19299788.

