Microcirculatory Changes Due to the Pneumoperitoneum

Abstracts / Journal of Minimally Invasive Gynecology 16 (2009) S103eS157 Intervention: MRgFUS ablation of fibroids using the ExAblate 2000 device according to the FDA commercial treatment guidelines. Measurements and Main Results: A total of 279 fibroids were treated with MRgFUS. Fibroids were classified by their intensity on T2 weighted images (GE SIGNA 1.5 T) relative to the normal myometrium (hyperintense, isointense, hypointense), and consistency of the fibroid (homogeneous, heterogeneous). Fibroids grouped by intensity: hyperintense (3.2%), isointense (10.4%), hypointense (61.6%), unclassified (24.7%). Fibroids grouped by consistency: homogeneous (15.4%), heterogeneous (48.0%), unclassified (36.6%). The NPV ratio was calculated as a percent of total fibroid load and as a percent of individual fibroid volume. The average total NPV was 50.8% whereas the average fibroid NPV was 55.2%. The NPV ratio for homogenous fibroids (59.2%) was greater than that for heterogeneous fibroids (51.5%) and the NPV ratio for hypointense fibroids (56.1%) was greater than that for hyperintense (29.1%) and isointense fibroids (42.2%). Trends between other treatment parameters and the percentage of hyperintense/heterogeneous fibroids at each site were identified (e.g. greater number of sonications at sites with greater percentage of hyperintense fibroids) and should be investigated further. Conclusion: Fibroid characteristics play a role in the success of MRgFUS treatment, as indicated by higher NPV ratio. Based on these results, the ‘‘ideal’’ fibroid would appear hypointense on T2 weighted images and homogeneous in intensity throughout the fibroid. The consideration of fibroid characteristics during patient evaluation and determination of candidacy for MRgFUS treatment could lead to improved treatment outcomes. 554 Microcirculatory Changes Due to the Pneumoperitoneum Ott D. Biomedical Engineering, Mercer University, Macon, GA Study Objective: Circulatory and perfusion changes occur due to increased pressure from a pneumoperitoneum. The extent of intra-abdominal organ and tissue perfusion resulting from intra-abdominal pressure (IAP) on tissue perfusion during laparoscopy is the focus of this study. Design: Measurement of microcirculatory changes due to IAP during laparoscopy. Setting: University laboratory. Patients: Six pigs. Intervention: Laparoscopy was performed using six pigs with IAP of 0, 10, 14 and 20 mm Hg using CO2, He and air. Changes is blood flow to the parietal peritoneum, rectus sheath, stomach, duodenum, jejunum, liver, mesenteric artery, cecum, colon, ovary and fallopian tube blood flow was measured using laser Doppler flowmetry probe. Measurements and Main Results: Normal systemic arterial blood pressure and respiratory function were maintained. All structures decreased blood flow with increasing IAP. Significant decreases in percent (%) blood flow and microcirculatory perfusion occurred with increasing IAP from 0 mm Hg to 10, 14 and 20 mm Hg are seen in Table 1. No statistical difference was seen between gases.

Percent decrease in blood flow with changes in IAP 0 mm Hg IAP50

% change from 10e14 mm Hg

14-20 mm Hg (total % change)

Peritoneum Rectus sheath Stomach Duodenum Jejunum Liver Mesenteric artery Cecum Colon Ovary Fallopian tube

553 273 472 91 291 362 383 322 382 131 482

182 173 122 31 51 61 262 71 91 41 142

(73) (44) (59) (12) (34) (42) (64) (39) (47) (17) (62)

S155

Percent decrease in blood flow from 10-14 mm Hg, additional percent decrease from 14e20 mm Hg and total percent change with 20 mm Hg IAP. Conclusion: When the end point of abdominal wall compliance is reached increasing intra-abdominal pressure severely compromises tissue blood flow and is independent of the gas used.

555 Perfusion Changes Caused by Intra-Abdominal Pressure during Laparoscopy Ott D. Biomedical Engineering, Mercer University, Macon, GA Study Objective: Little is known about the reduction in tissue perfusion caused by acutely increasing intra-abdominal pressure (IAP) during laparoscopy. Measurement of the changes in tissue perfusion with increasing IAP during laparoscopy is the purpose of this study. Design: Analysis of microcirculatory changes in tissue perfusion due to IAP. Setting: University laboratory. Patients: Twelve pigs. Intervention: Laparoscopy was performed on 12 pigs with IAP of 0, 10, 14, and 20 mm Hg using carbon dioxide. Observation points were parietal peritoneum, rectus sheath, stomach, duodenum, jejunum, liver, mesenteric artery, cecum, colon, ovary and fallopian tube blood flow measured using laser Doppler flowmetry. Measurements and Main Results: Normal systemic arterial blood pressure and respiratory function were maintained. All structures decreased blood flow with increasing IAP. Significant decreases in percent (%) blood flow and microcirculatory perfusion occurred with increasing IAP from baseline 0 mm Hg to 10, 14 and 20 mm Hg are seen in Table 1. Conclusion: Tissue structure and compliance is overcome by IAP resulting in perfusion changes. Increased IAP causes a significant decrease in microcirculatory blood flow to tissues within the abdominal cavity.

Table 1. Percent decrease in blood flow from 10-14 mm Hg, additional percent decrease from 14-20 mm Hg and total percent change with 20 mm Hg IAP

0 mm Hg IAP50

% change from 10e14 mm Hg

14-20 mm Hg (total % change

Peritoneum Rectus sheath Stomach Duodenum Jejunum Liver Mesenteric artery Cecum Colon Ovary Fallopian tube

553 263 452 91 291 362 403 342 392 141 472

182 153 122 31 51 61 292 71 91 41 132

(73) (41) (57) (12) (34) (42) (69) (41) (48) (18) (60)

556 A Comparison of Uterine Fibroid Embolization Versus Laparoscopic Myomectomy or Hysterectomy for Symptomatic Uterine Fibroids Petrozza JC,1 Chauhan A,1 Salazar G.2 1Obstetrics and Gynecology, Massachusetts General Hospital, Boston, MA; 2Interventional Vascular Radiology, Massachusetts General Hospital Study Objective: To determine if uterine fibroid embolization (UFE) provides any benefit versus the newer modalities of laparoscopic hysterectomy or myomectomy.