Shalini, Cynthia (2011) A Randomised Controlled trial to compare Pulse Pressure Variance and Central Venous Pressure as guide to intraoperative fluid management in Neurosurgical Patients. Masters thesis, Christian Medical College, Vellore.
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Abstract
INTRODUCTION: Anaesthesia for neurosurgery has many challenges. The emphasis remains on the provision of good operative conditions, assessment and preservation of neurological function, and a rapid, high-quality recovery. Fluid management intraoperatively plays a major role in achieving these goals of neurosurgery. Candidates presenting for intracranial surgery may be at risk of hypovolaemia for different reasons, including insufficient fluid intake, physiological compensation for arterial hypertension, and osmotic diuretic therapy. Formula based fluid management is inappropriate in these situations and so therapy has to be individualised. Individualised ‘Goal-directed fluid therapy’ has been shown to improve outcome after surgery. Various indices have been derived to calculate fluid responsiveness and volemic status. These include O2 transport and hemodynamic variables such as mixed venous saturation, O2 delivery, stroke volume estimation, and pulmonary artery pressure which can be measured only with highly invasive monitoring. Dynamic indices such as pulse pressure variation, stroke volume variation and systolic pressure variation are considered reliable monitors for fluid responsiveness and are more practical. Among these, pulse pressure variation has been shown to have a high sensiivity and specificity. Our aim in this study was to see if fluid therapy guided by PPV variation is reliable in neurosurgical patients and to compare this with CVP guided therapy. Aims and objectives: 1. To study the use of PPV as index of fluid management in neurosurgery and compare this with CVP To assess the intraoperative hemodynamic stability using this therapy. 2. To study the adequacy of tissue perfusion at the end of surgery as measured by acid base and lactate levels and post operative fluid management. MATERIALS AND METHODS: Type of study: A randomised controlled trial. Inclusion criteria: 1. Patients planned for craniotomy between the ages of 18- 80 years. 2. Surgeries lasting more than two hours duration. 3. Patients planned for craniotomy for tumour excision. 4. Surgery in Supine and lateral position. Exclusion criteria: 1. Patients with arrhythmia. 2. Patients with chronic obstructive lung diseases and those with poor chest compliance. 3. Patients with raised intra abdominal pressures. 4. Patients who are not mechanically ventilated. 5. Patients on drugs producing lactic acidosis including metformin. 6. Patients in sepsis. 7. Patient with baseline lactate more than 4. 8. Patients undergoing surgery in prone and sitting position. Method of randomization: Block randomization. Method of allocation concealment: Sequentially numbered, sealed, opaque envelopes. Methodology: Clearance was obtained from the institutional review boards and the ethics committee to perform the study in its present format. Once the randomization was done the patient was met by the investigator and informed consent obtained. The patient was fasted minimum of six hours for solids and two hours for liquids. Anxiolytic premedication was avoided in patients with raised intracranial pressure. Intravenous infusion was started using a wide bore cannula in a peripheral vein and direct arterial pressure monitoring established under local anaesthesia. A baseline arterial blood gas was taken with patient breathing room air. Other monitoring included pulse oximetry, capnography and electrocardiography. Anaesthesia was induced with thiopentone 5mg/kg, Fentanyl 2mcg/kg, and maintained on isoflurane end tidal concentration at 0.9% (MAC 0.8). in air and oxygen. Muscle relaxation was achieved using vecuronium 0.15mg/kg for endotracheal intubation and maintained with an infusion titrated to 2 twitches on neuromuscular monitoring. Patients were mechanically ventilated with a minimum of 8ml/kg of tidal volume and appropriate respiratory rate to achieve an ETCO2 between 30 and 35 mmHg. Statistical Analysis: All baseline variables were summarized using descriptive statistical methods (Mean, Standard deviation, Frequencies and Percentages). The outcome variables were compared between the two groups using Independent two-sample t-test, if they are normally distributed. For variables which are not normally distributed, Mann-whitney U test was used to compare the medians between the groups. Paired t-test was used for within group comparisons. All statistical analyses was done using SPSS 11.0. CONCLUSION: 1. Our study proves that pulse pressure variation (PPV) is a reliable and easily monitored index for fluid therapy in neurosurgical patients undergoing craniotomies in supine and lateral position. 2. Fluid management using PPV is as efficacious as using CVP as a guide for fluid management in patients with normal cardiac function. Despite a significantly larger blood loss in the PPV group, intraoperative hemodynamic stability and postoperative acid base and lactate level were comparable in the two groups. 3. No patient had signs of fluid overload in either group. 4. The acid base status was acceptable in both groups. Though PH were within normal limits, both groups had patients with higher than normal lactate levels. The cause for lactate cannot not be explained on the blood loss, change in pH, volume of fluid infused, duration of surgery or size of tumour. 5. There was no significant hemodynamic instability in any patient in the postoperative period.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Pulse Pressure Variance ; Central Venous Pressure ; intraoperative fluid management ; Neurosurgical Patients ; Randomised Controlled trial. |
| Subjects: | MEDICAL > Anaesthesiology |
| Depositing User: | Subramani R |
| Date Deposited: | 30 Apr 2018 02:54 |
| Last Modified: | 30 Apr 2018 02:54 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/7326 |
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