Acute Hip Fracture and Spinal Anaesthesia Injection Time

Overview

The systemic effects of spinal anesthesia is not fully known. Our aim of this study is to assess whether there is a difference in hemodynamic effects if the spinal dose is given fast (15s) or slow (90s) in elderly patients with acute hip fracture (AHF). Ninety (n=90) patients with AHF planned for surgery within 72h at our hospital will be enrolled in the study and randomly devided into two groups. The patients will receive one predetermined dose of spinal anesthesia followed by an advanced minimally-invasive hemodynamic monitoring through an arterial line using FloTrac-system. The hemodynamic parameters will be conducted 10 minutes prior to the spinal anaesthesia and 30 minutes after the spinal block is given. Hypotension was defined as a fall in MAP \> 30 % or a MAP \<65mmHg.

Both general and spinal anesthesia is known for inducing hypotension, which may be a problem for the elderly patients, often with many co-morbidities, causing a risk of organ hypoperfusion. At our clinic the investigators have a great experience with the neuraxial technique when operating these patients. Based on clinical experience the investigators hypothesise that a slow injection rate of the spinal dos would reduce the incidence and degree of hypotension. The investigators also aim to study the changes in the hemodynamic response between the groups in more detail as mentioned below. Patients planned for acute hip fracture surgery in spinal anaesthesia at our hospital and fulfills the inclusion criteria will be included in our study. The investigators plan to include 90 patients, randomized in two groups where Group A will be given a spinal anaesthesia in 15s and Group B in 90s. After arriving to the preoperative area, the patients will be given 5 L oxygen on a face mask and a standard monitoring with ECG, pulse- oximetry will be started, followed by the placement of a venous cannula and a radial arterial line. The patients will also be given a fascia iliaca compartment block (FIC) with ropivacaine 3,75 mg/ml 35-40 ml for comfort. In addition, the FloTrac system will be set up, using the existing arterial line, for advanced hemodynamic monitoring including invasive mean arterial pressure (MAP), Cardiac Index (CI), Heart Rate (HR), Stroke Volume (SV) and System Vascular Resistance (SVR)/ (SVRI). A lumbal spinal anesthesia will be performed using a 25G pencil point needle. The intrathecal dose of anesthesia consists of isobar bupivacaine 5mg/ml 2,4 ml and fentanyl 50ug/ml 0,4ml. Sensory level will be monitored by "cold spray" Hypotension will be defined as a fall in MAP by \>30% or MAP \< 65 mmHg. As an surrogate factor for the aggregated time of hypotension the total amount of given vasopressor will be calculated.