Patients and Methods
Patient Selection
This project was undertaken as a quality improvement initiative at Baylor Scott & White Health, Temple, Texas. A retrospective analysis of patient records was performed and the need for formal evaluation was waived by our local IRB.
A retrospective review, from Jan 1st 2020 to July 31st 2021, of all isolated CABG patients from our institution was conducted. All patients who underwent simplified UF using Aquadex (Nuwellis, MN. USA) during their hospital course were included in this analysis. Charts were reviewed using the electronic medical records (Epic Systems, WI. USA) and patient’s demographics were extracted and shown in Table 1 and 2. The exclusion criteria were ages <18 years. The institution has adopted the cardiac enhanced recovery after surgery (ERAS) protocols for all our cardiac surgery patients. Hemodynamic monitoring (i.e., CVP, SvO2, CI, SVR) for goal directed therapy was performed using the HemoSphere advanced monitoring platform (Edwards Lifesciences, Irvine Ca).
The decision to perform simple UF in the post-operative period was made by the attending cardiothoracic surgeons in collaboration with the CVICU intensivists using our division’s protocol as summarized in Table 3.
Ultrafiltration Technique
Various modes of venous access were used including the previously placed intra-operative ARROW MAC with ARROWg+ard Blue Technology 9F catheter (Teleflex, USA, Fig 1), a peripheral dual lumen extended length catheter (dELC) 6F/16Ga (Nuwellis, MN US, Fig 2) or a standard central venous 14Ga or 16Ga hemodialysis (HD) catheter (not shown). The approximate time from UF request placed to initiation of fluid removal is typically 15 to 60 minutes once venous access is in place. Elective nephrology consultations were submitted, and emergent consultations were reserved for patients who met indications for hemodialysis. All diuretics were discontinued once UF was in progress. Most patients were anticoagulated with 400 to 600 Units Heparin per hour or Argatroban (to maintain PTT 40-50 secs) if heparin induced thrombocytopenia was suspected. The UF rates of fluid removal varied from 100cc to 500/cc per hour at the discretion of the surgeon, CVICU intensivist and ICU team using clinical, hemodynamic and biomarkers to guide GDT. Intermittent CVP readings were recorded from the central venous access line and goal directed therapy was utilized with the HemoSphere advanced monitoring platform (Edwards Lifesciences, Irvine Ca). The goal of UF was to target a net negative 1-2L /day until CVP was <12, O2 requirements were decreased, patient returned to baseline weight and or regained adequate renal function to become diuretic responsive.
Statistical Methods
This was a retrospective study. Descriptive statistics were used including sample size, mean, standard deviation, median, minimum, and maximum for continuous variables and frequency and percent for categorical variables.