Safety and Feasibility of High-Pressure/High-Dose Pressurized Intraperitoneal Aerosol Chemotherapy (HP/HD-PIPAC) for Primary and Metastatic Peritoneal Surface Malignancies.

OBJECTIVE: The aim of this study was to evaluate the feasibility and perioperative safety of high-pressure/high-dose pressurized intraperitoneal aerosol chemotherapy (HP/HD-PIPAC) to manage peritoneal surface malignancies (PSM). METHODS: Retrospective analysis of a prospective database of about 130 consecutive patients scheduled for HP/HD-PIPACs for PSM. Doxorubicin plus cisplatin (PIPAC-C/D) or oxaliplatin (PIPAC-Ox) were nebulized into a constant capnoperitoneum of 20 mmHg at doses of 6, 30, or 120 mg/m2 of body surface area (BSA). Outcome criteria were perioperative complications (Clavien-Dindo). RESULTS: The median age of patients was 62 years (range 9-82), and the primary tumor site was of colorectal (CRC), upper gastrointestinal tract (UGI), unknown primary (CUP), malignant epithelioid mesothelioma of the peritoneum (MPM), hepato-pancreatic-biliary tract (HPB), and other origin in 30 (23.1%), 27 (20.8%), 16 (12.3%), 16 (12.3%), 6 (4.6%), and 35 (26.9%) patients, respectively. Abdominal access failed for a first, second, third, and fourth or more HP/HD-PIPAC in 12/130 (9.2%), 4/64 (6.3%), 6/40 (15.0%), and 2/33 (6.1%) patients. A total of 243 procedures were performed in 118 patients. No intraoperative complications related to increased capnoperitoneal pressure occurred, but an intraoperative bleeding complication was observed in 1/243 (0.4%) patients. The overall rate of postoperative procedure-related complications was 19.3% (47/243), while 15.3% (37/243), 1.6% (6/243), 1.6% (1/243), 0.4% (1/243), and 0.4% (1/243) were Grade I, II, III, IV, and V complications, respectively. CONCLUSIONS: Perioperative complications of HP/HD-PIPAC are comparable with standard pressure/dose PIPAC treatment protocols. Prospective studies are warranted to examine potential improvement in therapy outcomes.

Development and technical validation of an ultrasound nebulizer to deliver intraperitoneal pressurized aerosols in a rat colon cancer peritoneal metastases model.

BACKGROUND/AIM: To develop and validate a nebulizer device for anti-cancer research on pressurized intraperitoneal aerosol supply in a preclinical peritoneal metastases (PM) rat model. MATERIAL AND METHODS: For aerosol generation, an ultrasonic nebulizer (USN) was modified. Aerosol analyses were performed ex-vivo by laser diffraction spectrometry (LDS). Intraperitoneal (IP) 99mtechnetium sodium pertechnetate (99mTc) aerosol distribution and deposition were quantified by in-vivo single photon emission computed tomography (SPECT/CT) and compared to liquid IP instillation of equivalent volume/doses of 99mTc with and without capnoperitoneum. PM was induced by IP injection of HCT116-Luc2 human colon cancer cells in immunosuppressed RNU rats. Tumor growth was monitored by bioluminescence imaging (BLI), 18F-FDG positron emission tomography (PET) and tissues examination at necropsy. RESULTS: The USN was able to establish a stable and reproducible capnoperitoneum at a pressure of 8 to 10 mmHg. LDS showed that the USN provides a polydisperse and monomodal aerosol with a volume-weighted diameter of 2.6 µm. At a CO2 flow rate of 2 L/min with an IP residence time of 3.9 s, the highest drug deposition efficiency was found to be 15 wt.-%. In comparison to liquid instillation, nebulization showed the most homogeneous IP spatial drug deposition. Compared to BLI, 18F-FDG-PET was more sensitive to detect smaller PM nodules measuring only 1-2 mm in diameter. BLI, 18F-FDG PET and necropsy analyses showed relevant PM in all animals. CONCLUSIONS: The USN together with the PM rat model are suitable for robust and species-specific preclinical pharmacological studies regarding intraperitoneal delivery of pressurized aerosolized drugs and cancer research.

Development of a rat capnoperitoneum phantom to study drug aerosol deposition in the context of anticancer research on peritoneal carcinomatosis.

Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a promising approach with a high optimization potential for the treatment of peritoneal carcinomatosis. To study the efficacy of PIPAC and drugs, first rodent cancer models were developed. But inefficient drug aerosol supply and knowledge gaps concerning spatial drug distribution can limit the results based on such models. To study drug aerosol supply/deposition, computed tomography scans of a rat capnoperitoneum were used to deduce a virtual and a physical phantom of the rat capnoperitoneum (RCP). RCP qualification was performed for a specific PIPAC method, where the capnoperitoneum is continuously purged by the drug aerosol. In this context, also in-silico analyses by computational fluid dynamic modelling were conducted on the virtual RCP. The physical RCP was used for ex-vivo granulometric analyses concerning drug deposition. Results of RCP qualification show that aerosol deposition in a continuous purged rat capnoperitoneum depends strongly on the position of the inlet and outlet port. Moreover, it could be shown that the droplet size and charge condition of the drug aerosol define the deposition efficiency. In summary, the developed virtual and physical RCP enables detailed in-silico and ex-vivo analyses on drug supply/deposition in rodents.

Experimental Model to Test Electrostatic Precipitation Technology in the COVID-19 Era: A Pilot Study.

BACKGROUND: In the COVID-19 crisis, laparoscopic surgery is in focus as a relevant source of bioaerosol release. The efficacy of electrostatic aerosol precipitation (EAP) and continuous aerosol evacuation (CAE) to eliminate bioaerosols during laparoscopic surgery was verified. STUDY DESIGN: Ex-vivo laparoscopic cholecystectomies (LCs) were simulated ± EAP or CAE in Pelvitrainer equipped with swine gallbladders. Release of bioaerosols was initiated by performing high-frequency electrosurgery with a monopolar electro hook (MP-HOOK) force at 40 watts (MP-HOOK40) and 60 watts (MP-HOOK60), as well as by ultrasonic cutting (USC). Particle number concentrations (PNC) of arising aerosols were analyzed with a condensation particle counter (CPC). Aerosol samples were taken within the Pelvitrainer close to the source, outside the Pelvitrainer at the working trocar, and in the breathing zone of the surgeon. RESULTS: Within the Pelvitrainer, MP-HOOK40 (6.4 × 105 cm-3) and MP-HOOK60 (7.3 × 105 cm-3) showed significantly higher median PNCs compared to USC (4.4 × 105 cm-3) (p = 0.001). EAP led to a significant decrease of the median PNCs in all 3 groups. A high linear correlation with Pearson correlation coefficients of 0.852, 0.825, and 0.759 were observed by comparing MP-HOOK40 (± EAP), MP-HOOK60 (± EAP), and USC (± EAP), respectively. During ex-vivo LC and CAE, significant bioaerosol contaminations of the operating room occurred. Ex-vivo LC with EAP led to a considerable reduction of the bioaerosol concentration. CONCLUSIONS: EAP was found to be efficient for intraoperative bioaerosol elimination and reducing the risk of bioaerosol exposure for surgical staff.