The aim of the study is to compare the hemodynamic parameters of fluid resuscitation using Rohrich formula to cardiometry guided stroke volume variation in patients undergoing large volume liposuction surgery .

The study will done on 50 patients divided equally into two groups. Group A Fluid administration in the form of lactated ringer will be managed by Rohrich formula and the intraoperative fluid ratio (subcutaneous infiltration fluid plus intravenous fluid divided by total aspirate volume) will be 1.2. Rohrich formula represents fluid maintenance,deficit and replacement fluid ( 0.25 ml crystalloid given for each 1 ml above 4 litre of lipoaspirate).

Group B Patients will receive fluid maintenance of lactated ringer 2 ml/kg/h, cardiometry guided stroke volume variation will be measured before and after induction then every 30 min ,it ranges between 5-15%, fluid bolus of lactated ringer 4 ml /kg over 15 min will be administered if stroke volume variation ˃ 15% .

Electrical cardiometry will be connected to the patient before induction,the skin will be clean and dry before placing the electrodes. Four electrodes will be applied, first one is at the upper part of the anterior aspect of the neck, second one is 5 cm below the first electrode at lower part of the neck, third one at the lower left thorax in line with xiphoid process at the level of anterior axillary line and the fourth one is 5 cm below the third electrode at the level of anterior axillary line.Electrical cardiometry will be connected to the sensor cable and the patient data will be applied as (gender - age - height - weight - blood pressure -heart rate - hemoglobin and oxygen saturation).

Surgical Technique The wetting solution will be lactated ringer with epinephrine 1mg on 1 litre so concentration is 1:1,000,000.10 ml lidocaine 2% will be added.Subcutaneous infiltration of the wetting solution will facillate dissection and removal of fat ,the technique that will be used is traditional liposuction , suction assisted liposuction with super wet technique ( the amount of infiltration solution is equal to the amount of fat aspirate).

The liposuction cannula is a multihole blunt tip cannula with a diameter of 3 to 6 mm, 4-6 mm for deep liposuction,2-4 mm for superficial liposuction and a length ranging between 10 to 30 cm. The surgeon will inject the wetting solution to the target area until it becomes tense then infiltrates the other side waiting 10 to 15 min after infiltration to begin suction .The aspirate will be collected in suction container, fat will separate from solution after approximately 1-2 h by gravity into upper yellowish part includes fat called supernatant and lower part includes blood tinged fluid called infranatant.

Measurements

• Noninvasive blood pressure ,oxygen saturation, Heart rate before induction, 5 min and 15 min after induction then every 30 min.
• Urine output, baseline and every hour.
• Venous blood sample for measurement of hemoglobin and hematocrit level after aspiration of 4 litre of fat and for every litre after.
• Measurement of blood volume in aspirate by taking a sample from infranatant part after its separation from fat for hemoglobin level calculation and by equation of multiplying this hemoglobin concentration to infranatant volume divided by preoperative hemoglobin concentration, the investigators can measure blood volume in aspirate .
• Amount of intravenous and infiltration fluids.
• Amount of fat and total aspirate.
• Stroke volume variation before and after induction then every 30 min.

Inclusion Criteria:

• Male and female patients aged between 21 to 60 years.
• American Society of Anesthesiologists (ASA) Ӏ& ӀӀ.
• Large volume liposuction.

Exclusion Criteria:

• Any bleeding& coagulation disorders.
• Patients on regular anticoagulant or antiplatelet drugs.
• History of previous surgery in treated areas.
• Significant cardiopulmonary, hepatic or renal disease.