Nairon EB, Joseph J, Kamal A, Busch DR, Olson DM. The Presence of Blood in a Strain Gauge Pressure Transducer Has a Clinical Effect on the Accuracy of Intracranial Pressure Readings.
Crit Care Explor 2024;
6:e1089. [PMID:
38728059 PMCID:
PMC11086962 DOI:
10.1097/cce.0000000000001089]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024] Open
Abstract
IMPORTANCE
Patients admitted with cerebral hemorrhage or cerebral edema often undergo external ventricular drain (EVD) placement to monitor and manage intracranial pressure (ICP). A strain gauge transducer accompanies the EVD to convert a pressure signal to an electrical waveform and assign a numeric value to the ICP.
OBJECTIVES
This study explored ICP accuracy in the presence of blood and other viscous fluid contaminates in the transducer.
DESIGN
Preclinical comparative design study.
SETTING
Laboratory setting using two Natus EVDs, two strain gauge transducers, and a sealed pressure chamber.
PARTICIPANTS
No human subjects or animal models were used.
INTERVENTIONS
A control transducer primed with saline was compared with an investigational transducer primed with blood or with saline/glycerol mixtures in mass:mass ratios of 25%, 50%, 75%, and 100% glycerol. Volume in a sealed chamber was manipulated to reflect changes in ICP to explore the impact of contaminates on pressure measurement.
MEASUREMENTS AND MAIN RESULTS
From 90 paired observations, ICP readings were statistically significantly different between the control (saline) and experimental (glycerol or blood) transducers. The time to a stable pressure reading was significantly different for saline vs. 25% glycerol (< 0.0005), 50% glycerol (< 0.005), 75% glycerol (< 0.0001), 100% glycerol (< 0.0005), and blood (< 0.0005). A difference in resting stable pressure was observed for saline vs. blood primed transducers (0.041).
CONCLUSIONS AND RELEVANCE
There are statistically significant and clinically relevant differences in time to a stable pressure reading when contaminates are introduced into a closed drainage system. Changing a transducer based on the presence of blood contaminate should be considered to improve accuracy but must be weighed against the risk of introducing infection.
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