An in vitro study comparing a peripherally inserted central catheter to a conventional central venous catheter: no difference in static and dynamic pressure transmission

Abstract

Background: Early goal directed therapy improves survival in patients with septic shock. Central venous pressure (CVP) monitoring is essential to guide adequate resuscitation. Use of peripherally inserted central catheters (PICC) is increasing, but little data exists comparing a PICC to a conventional CVP catheter. We studied the accuracy of a novel PICC to transmit static and dynamic pressures in vitro.

Methods: We designed a device to generate controlled pressures via a column of water allowing simultaneous measurements from a PICC and a standard triple lumen catheter. Digital transducers were used to obtain all pressure readings. Measurements of static pressures over a physiologic range were recorded using 5Fr and 6Fr dual lumen PICCs. Additionally, random repetitive pressure pulses were applied to the column of water to simulate physiologic intravascular pressure variations. The resultant PICC and control waveforms were recorded simultaneously.

Results: Six-hundred thirty measurements were made using the 5 Fr and 6 Fr PICCs. The average bias determined by Bland-Altman plot was 0.043 mmHg for 5 Fr PICC and 0.023 mmHg for 6 Fr PICC with a difference range of 1.0 to -1.0. The correlation coefficient for both catheters was 1.0 (p-value < 0.001). Dynamic pressure waveforms plotted simultaneously between PICC and control revealed equal peaks and troughs.

Conclusion: In vitro, no static or dynamic pressure differences were found between the PICC and a conventional CVP catheter. Clinical studies are required to assess whether the novel PICC has bedside equivalence to conventional catheters when measuring central venous pressures.

Figure 1

5 French PICC Bland-Altman Plot. The average bias determined by the plot is 0.043 mmHg with a standard error of zero. The difference range is -1 to 1 mmHg.

Figure 2

6 French PICC Bland-Altman Plot. The average bias determined by the plot is 0.023 mmHg with a standard error of zero. The difference range is 0 to 1 mmHg.

Figure 3

5 French PICC Static Pressure Scatter Plot. Four hundred and twenty measurements comparing the pressure recorded from ten 5 Fr PICCs on the x-axis and the control pressure on the y-axis. The correlation coefficient between the two catheters was 1.0 which results in a perfectly linear correlation and a y-intercept of essentially zero.

Figure 4

6 French PICC Static Pressure Scatter Plot. Two hundred and ten measurements comparing the pressure recorded from five 6 Fr PICCs on the x-axis and the control pressure on the y-axis. The correlation coefficient between the two catheters was 1.0 which results in a perfectly linear correlation and a y-intercept of essentially zero.

Figure 5

Pressure Waveforms. Dynamic pressure waveforms comparing the 5 Fr and 6 Fr PICC to the 7 Fr triple lumen control. There is some phase delay in the PICC waveform. However, the peaks, troughs, and means are equal even at 300 cycles per minute.