SESSION TITLE: Pleural Disease Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PM
PURPOSE: During thoracentesis, vacuum is created in the pleural space with manual suction using a syringe. Normal pleural pressure is -9 to -11cm H2O. However, there are no published reports on how much negative pressure is generated with a large syringe. We did a pilot study to evaluate the effect of experience and manometry during a simulated thoracentesis.
METHODS: A 60cc syringe was connected through an inline digital manometer (Compass, Mirador Biomedical Inc.) to a 1L saline bag. Attendings(A), pulmonary fellows(F), residents(R) and medical students(S) (5 in each group) were instructed to first aspirate 60cc saline as if they are doing a thoracentesis while pressures and duration were recorded in a blinded fashion. They were then asked to repeat the procedure while monitoring the manometer to keep the pressure below -20cm H2O. Five readings were taken per person each time to calculate the average duration and pressure. Two way ANOVA with bonferroni comparison was used with two tailed p-value at 0.05 level of significance for statistical comparison.
RESULTS: There were 20 participants. Although the fellows generated the lowest pressure (-148±54cmH2O) and took longer (27±7sec) while blinded to manometry there was no significant difference compared to others (A -286±198cmH20/18±12sec, R -269±130cmH2O/17±5sec, S -240±101cmH2O/20±5sec) (ANOVA p>0.05). Significant differences were noted in pressures and durations when blinded readings were compared to monitored manometer readings for all groups (p=0.0001). Students have longest durations (185±79sec) while watching manometer compared to others (A 82±38sec, F 124±35sec, R 116±29sec). Procedure duration was statistically significant when students were compared to the other groups (ANOVA p=0.021) for monitored readings. Though not statistically different, attendings tend to generate more negative pressure (-83±87cmH2O) even while watching the manometer compared to others (F -30±18cmH2O R -24±2cmH2O, S -17±5cmH2O).
CONCLUSIONS: While significantly lower negative pressure is created during manual aspiration, level of training does not affect the generated pressure or procedure duration when blinded to manometry. Medical students are more likely to maintain a negative pressure of -20cmH2O during aspiration compared to others.
CLINICAL IMPLICATIONS: Manometry readings during aspiration drastically impact the pressures generated during simulated thoracentesis irrespective of experience level and may be helpful in preventing re-expansion pulmonary edema or pneumothorax-ex vacuo.
DISCLOSURE: The following authors have nothing to disclose: Muralidhar Kondapaneni, Rebecca Cloyes, Soud Sediqe, Shaheen Islam
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