Goal-directed Therapy in High-risk Surgery

A Randomized Study of Goal-directed Therapy in the Elderly High-risk Patients Undergoing Total Hip Replacement

There is growing evidence that the risk of postoperative complications can be decreased by optimizing the amount and type of infusion fluids given during surgery, steered by goal-directed therapy based on flow-related hemodynamic parameters, particularly in high-risk patients. This study is undertaken subsequently to test the hypothesis that the intraoperative goal-directed strategy based on FloTrac/Vigileo, a minimally invasive monitor, can partially prevented postoperative complications and shorten hospital stay in the elderly high-risk patients undergoing total hip replacement with continuous spinal anaesthesia .

After sedated with IV 0.02 mg/kg midazolam, all patients will receive arterial, central venous, and L3-4 intrathecal catheterizations. A T12 sensory level block was attained with ropivacaine through the intrathecal catheter. Besides currently recommended monitoring during the intraoperative period, arterial blood pressure, stroke volume (Edwards Lifesciences, Irvine, Calif.), and central venous oxygen saturation (Edwards Lifesciences) will be measured and recorded. All Patients will receive intranasal oxygen 2 mL/min and be kept normothermic (body temperature > 36°C). Patients in both groups receive 8 mL/kg/hour of Ringer's lactate solution from 30 minutes prior to induction of anaesthesia through the end of surgery, when the rate will be decreased to 100 mL/hour. In addition, boluses of colloid will be given to different protocol group according to the study arm to which the patient allocated.Postoperative care and discharge criteria were predefined using the hospital care map and protocol.

ensure SpO2≥ 92%, MAP 65-100 mmHg, HR <100 bpm, Hb> 8mg/dL and temperature ≥ 36℃, the patients were then administrated a 200 ml colloid as a fluid challenge. The fluid challenge repeat until the SV failed to increase by a factor of 10%. If at this stage the DO2I can not be greater than 600 mL/m2, then dobutamine will be started at a dose of 2.5 μg/kg/min and increased by the same increment every 20 minutes until the described target is reached or until a maximal dose of 20 μg/kg/min is given. Dobutamine is decreased in dose or discontinued if the heart rate is above 120 beats per minute or shows signs of cardiac ischemia. Blood transfusions will be used to maintain a hemoglobin concentration over 8mg/dL

The goal of this protocol is to ensure MAP> 65 mmHg, CVP 8-12 cmH2O. If meet the above requirements, do nothing, re-evaluate after 5min. If CVP <8 cmH2O, the patient will receive an additional 200ml colloid .If MAP beyond the scope of 65-100 mmHg, vasoactive agents will be administrated until achieve the goal. If 25mL/kg colloid given before goal is achieved, fluid challenges will then be performed with 200mL boluses of Ringer's lactate solution. Blood transfusions will be used to maintain a hemoglobin concentration over 8mg/dL

Major complications: Infection , Major cardiovascular complications , Pulmonary Embolism, Renal Failure, Anaemia requiring blood transfusion in the presence of shock. Minor complications: Hypotension (systolic blood pressure < 90 mmHg) requiring fluid boluses, Uncomplicated infections (not requiring intra-venous antibiotic therapy and with no signs of sepsis, i.e. uncomplicated urinary tract infections), Anemia requiring blood transfusions in the absence of shock. PONV: Postoperative Nausea and Vomiting delirium and postoperative cognitive dysfunction mortality

Inclusion Criteria: 1. Adult patients scheduled for total hip replacement at this institution. 2. American Society of Anaesthesiologists (ASA) physical status of III or VI. 3. Two or more risk factors according to risk index of Lee . Exclusion Criteria: 1. Age under 70years old 2. idiopathic coagulopathy: with warfarin or heparin 3. systemic or local infection 4. unable to cooperate 5. spinal trauma or severe low back pain history 6. patient refusal.

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