Can procedure time for paracentesis be optimized based on bottle selection?

The purpose of our study was to assess if plastic containers could decrease the overall procedure time for paracentesis relative to more commonly used glass containers.

In this IRB exempt study, initial pilot data comparing filling time of glass and plastic containers in an ex vivo setting under identical conditions revealed power calculations that n = 37 patients per group would be needed to achieve standard deviation (SD) = 60 s, difference (diff) = 40 s, two-tailed alpha-level 0.05, and power 80%. Total of 43 patients (93 containers) were enrolled and randomized to glass or plastic bottles at enrollment. Timing of bottle filling was assessed using standardized sonographic screen captures.

An interim look at statistics at n = 20 patients indicated that original conjectures from pilot data were conservative and smaller sample size was sufficient to stop the study and conduct the analyses. Specifically, SD = 54 s, diff = 49 s, two-tailed alpha-level 0.05, and power 80% required n = 21 patients per group. Plastic containers had a statistically significantly lower average filling time per bottle (162.7 ± 53.3 s) compared to glass (212.2 ± 50.4 s) (p = 0.003). Viscosity was calculated for each specimen and did not affect the statistical significance of the results (p = 0.32).

Plastic containers have 50 s time savings of per bottle filling time as compared to glass bottles as theorized based on their faster flow rate. This holds true in both an ex vivo setting and in patients and can have important downstream impacts on patient throughput, provider efficiency and system wide cost savings.