Comparison of water manometry to 2 commercial electronic pressure monitors for central venous pressure measurement in horses.

The research paper investigates the difference between the traditional water manometry method of measuring Central Venous Pressure (CVP) in horses and two types of commercial electronic monitors. The study found that while both electronic devices tend to give readings that are almost 2 cmH₂O lower than water manometry, the differences between the electronic devices themselves are minor.

Research Objective

The aim of the study was to assess the correlation and differences between the water manometry and electronic monitors for measuring Central Venous Pressure (CVP) in horses. The researchers hypothesized that the readings from the electronic monitoring devices would align with those from water manometry.

Methodology

• The study was conducted on ten healthy adult horses from the university research herd.
• Central venous catheters were inserted as per routine and measurements were taken three times using each of the three methods every twelve hours for a span of three days.
• The data were then statistically analyzed using the Lin concordance correlation coefficient, and the modified Bland-Altman limits of agreement. The devices were compared pairwise.

Results

• Findings showed that in comparison to water manometry, the difference (or bias) of the Passport was -1.94 cmH₂O (95% limits of agreement were between -8.54 cmH₂O and 4.66 cmH₂O).
• The bias of the Medtronic was -1.83 cmH₂O (95% limits of agreement, -8.60 to 4.94 cmH₂O).
• When the data from Medtronic was compared with the Passport, the bias was 0.27 cmH₂O (95% limits of agreement were between -4.39 cmH₂O and 4.93 cmH₂O).

Conclusions

• The findings suggest that both electronic monitors consistently returned measurements that are approximately 2 cmH₂O lower than water manometry.
• However, the discrepancy in the readings between the two electronic devices was less than 0.5 cmH₂O, considered by researchers to be clinically trivial.
• This is a significant discovery because it means clinicians using these electronic devices should factor in this discrepancy when interpreting data obtained from these monitoring devices.