Clinical trial NCT01873183: Perioperative Fluid Management in Morbidly Obese Patients
Official title: Perioperative Fluid Management With Transthoracic Echocardiography and Pulse-contour Device in Morbidly Obese Patients
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hypotension
Anomaly; Venous Return
Dehydration
Keywords: echocardiography
morbid obesity
bariatric surgery
venous return
mean arterial blood pressure
Lead sponsor: Umeå University
Sponsor class: OTHER
First posted: 2013-06-07
Enrollment: 50
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: In bariatric surgery functional and feasible non- or mini-invasive modalities for monitoring, and ideal/lean body weight estimates are addressed to meet up individual variability in hydration needs, and to avoid hyperhydration.

The aim of the study is to evaluate need of perioperative hydration by comparing conventional monitoring (the control group) to a more advanced approach (individualized goal-directed therapy, IGDT) (the intervention group). In addition to conventional cardiovascular monitoring (ECG, non-invasive blood pressure, Sp02) preoperative transthoracic echocardiography (TTE) and a intraoperative perioperative mini-invasive pulse-contour device (FloTrac™) will be used for the purpose.

Detailed description: The individualized goal-directed therapy (IGDT), with focus on level of venous return, will be implemented in two steps in the intervention group. First, preoperative optimizing of venous return will be performed 45 minutes before surgery in a preoperative room with TTE. Second, after induction of anaesthesia perioperative fluid therapy will be guided by utilizing the FloTrac-device.

Preoperative rehydration with 6 ml colloid fluids (Volulyte™, Fresenius Kabi Ab, Sweden) /kg estimated ideal body weight (IBW) will be administrated if low level of venous return is detected by TTE. After a colloid bolus the second TTE is performed to check the level of venous return. If remaining hypovolemia is found additional colloids 3ml/ kg IBW will be given.

In OR, before pneumoperitoneum, prophylactic i.v. antibiotics will be administrated in total 550ml crystalloids (NaCl 0.9%, Fresenius Kabi Ab, Sweden) to all patients. Infusion of buffered glucose solution (25mg/ml, Fresenius Kabi Ab, Sweden) at rate 1.5ml/kg IBW/h will be initiated to all patients. Stroke volume variation ≥ 12 % is used as a threshold for administration of additional colloids 3ml/kg/ IBW during surgery.

Postoperatively infusion of buffered glucose solution (50mg/ml) is administrated at fixed rate 100ml/h to all patients. In addition, during the stay at the postoperative ward unit 850 ml crystalloids (antibiotics, paracetamol and nonsteroidal antiinflammatory drugs) are infused.

Perioperative ephedrine and/or phenylephrine is used as i.v. injection when necessary to ensure adequate perfusion pressure (MAP ≥ 65 mmHg), cardiac index (≥ 2.0) and heart rate (≥ 50/min) in addition to i.v. fluids in both groups. In principle hemodynamic parameters will be gathered always after five minutes minimum from possible administration of i.v. ephedrine or phenylephrine. Moreover, if pre-existing systolic left ventricular failure is detected in preoperative TTE, infusion of dobutamine 3 - 4ug/kg IBW will be started 10 minutes before induction of anaesthesia.

In the control group perioperative cardiovascular monitoring will be conducted by ECG, non-invasive blood pressure and Sp02 measurements.

Eligibility criteria: Inclusion Criteria:

* accepted for bariatric surgery; BMI ≥ 40 kg/m2. Written informed consent. Successful preparation by 3 weeks rapid-weight-loss diet before surgery (≥ 5% loss of weight)

Exclusion Criteria:

* Subjects with untreated systemic or pulmonary hypertension, atrial fibrillation, pacemaker, unstable angina pectoris and significant failure of heart valves.

Primary outcomes:
measure: Need of perioperative i.v. fluids
timeFrame: 12 hours
Secondary outcomes:
measure: mean arterial blood pressure
timeFrame: 1 hour
Other outcomes:
measure: Nt-proBNP, creatinine
timeFrame: 12 hours
Locations:
city: Lulea
country: Sweden
facility: Department of anaesthesiology and intensive care, Sunderby county hospital
Study officials:
affiliation: Umea University
name: Tomi P Poso, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Poso T, Winso O, Aroch R, Kesek D. Perioperative fluid guidance with transthoracic echocardiography and pulse-contour device in morbidly obese patients. Obes Surg. 2014 Dec;24(12):2117-25. doi: 10.1007/s11695-014-1329-4.