Abstract

Introduction: To quantify the magnitude and incidence of haemodynamic changes that occurs during the fixation of extracapsular proximal femoral fractures when using either intra-medullary or extra-medullary fixation device.

Methods: A prospective group of 31 patients with extra-capsular proximal femoral fractures were randomised to either fixation using an extra-medullary compression hip screw or an intra-medullary hip screw. All patients received a general anaesthetic adhering to a standardised anaesthetic protocol including invasive blood pressure monitoring and arterial blood gas sampling. Trans-oesophageal Doppler probe and monitor was used to record pre-operative hypovolaemia and peri-operative changes in cardiac output, stroke volume and corrected flow time (FTc – a reflection of left ventricular end diastolic pressure) during placement of implants.

Results: 77% of patients were hypovolaemic preoperatively, which was corrected with an average of 439 mls of colloid replacement fluid. Application of the extra-medullary CHS produced no change in haemodynamic function. However on insertion of the IMHS we found a statistically significant reduction in stroke volume, cardiac output and FTc without changes in pulse rate or mean arterial pressure. The changes were transient with normal cardiac function returning by 5 mins post operatively.

Conclusion: The transient fall in cardiac function during insertion of the intramedullary hip screw may be caused by fat embolism entering the venous circulation. As these changes are not detected with standard non-invasive monitoring we would recommend that intramedullary devices be used with caution in elderly patients who tend to have poor physiological reserve.