Tumescent local anesthesia is a procedure which is frequently performed for plastic cosmetic surgical procedures such as liposuction. The subcutaneous adipose tissue is infiltrated with large volumes of a solution which also contain local anesthetics. However local anesthetics, can also lead to a marked production of methemoglobin. New generation pulse oximeters are able to measure SpMetHb non-invasivly.

The aim of this study is:

1. to investigate multi-wavelength pulse oximetry as a monitoring method for patients at increased risk for methemoglobinemia.
2. to illustrate MetHb concentrations over a course of 24 hours after a liposuction employing tumescent anesthesia has been carried out.

Inclusion Criteria:

• planned liposuction in tumescent local anesthesia

Exclusion Criteria:

• hematologic disorders

- female patients scheduled for liposuction