Thread by @critconcepts

Sara A Hennessy on managing ICU devices in obesity (#SCCM2023)

BP cuffs taken with too-small cuffs significantly higher. Should be 80% of upper arm circumference, width should be 40% of length. Large cuffs may still be poor fit, eg too long (obese arms aren't longer), and arms are "inverted cones" not cylinders.

Try an appropriate cuff on forearm, hold forearm at level of heart; hoses should exit over radial artery. Will vary by 7-15mmHg from upper arm.

Abdominal pressure in obesity: IAP may be elevated a little in obesity, but not by much (<1mmHg). IAH numbers in obesity is still IAH.

IV placement in obesity: try warming; displace edema/tissue; use multiple tourniquets; use a longer line; try translumination; avoid small collateral vessels. Mostly, use ultrasound.

CVC placement: more anatomic variation in neck; use ultrasound! may need to use an extended-access needle to reach vessel for wire placement. (Note: higher risk of damaging intrathoracic structures with long needle.)

Remember line can shift with tissue movement/repositioning and extravasate. Consider how much catheter is intravascular, and frequently check position; may need imaging.

BMI >40 = double risk of CLABSI

Placing doubled sono-opaque markers on US probe dramatically increases arterial cannulation success in obesity

Keyser: cannulation for VV ECMO technically harder but can have good outcomes and success.