In morbidly obese patients suspected of being hypovolemic, increased cardiovascular stability may be reached by preoperative rehydration. The management of rehydration should be individualized. Additional invasive monitoring does not appear to have any effect on outcomes in obesity surgery.

Morbid obesity and optimization of preoperative fluid therapy. AbstractContext: Preoperative venous return (VR) optimization and adequate blood volume is essential in management of morbidly obese patients (MO) in order to avoid perioperative circulatory instability. In this study, all subjects underwent a preoperative three-week preparation by rapid-weight-loss-diet (RWL) as part of their treatment program for bariatric surgery. Design: Prospective, observational study. Setting: Sunderby County Hospital, Luleå, Sweden. Subjects: Thirty-four morbidly obese patients consecutively scheduled for bariatric surgery. Interventions: Preoperative transthoracic echocardiography (TTE) was performed in the awake state before and after intravascular volume-challenge (VC) of 6 ml colloids/kg ideal body weight (IBW). Effects of standardized VC were evaluated by TTE. Dynamic and nondynamic echocardiographic indices for VC were studied. Main outcome measures: Volume-responsiveness and level of VR before and after VC were assessed by TTE. An increase of stroke volume (Δ SV) ≥ 13% was considered as a volumeresponder. Results: 29/34 patients were volume-responders. After VC, a majority of patients (23/34) were euvolemic, and only 2/34 were hypovolemic. Post VC hypervolemia was observed in 9/34 of patients. Conclusions: The IBW-based volume challenge regimen was found to be suitable for preoperative rehydration of RWL-prepared MO. Most of the patients were volumeresponders. Preoperative state of VR was not associated with volume-responsiveness. IBWestimates and appropriate monitoring avoids potential hyperhydration in MO. For VC assessment, conventional Doppler indices were found to be more suitable compared to tissue Doppler, giving sufficient information on pressure-volume correlation of the left ventricle in morbidly obese.

A combination of sevoflurane, propofol, suxamethonium and alfentanil is a suitable method for RSI which maintains cardiovascular and respiratory stability in both morbidly obese and lean patients.

Preoperative RWL may induce hypovolemia in morbidly obese patients. Hypovolemia in MO was more common vs. lean controls. TTE is a rapid and feasible tool for assessment of preload even in morbid obesity.