Pulmonary embolism detected by transesophageal echocardiography during cemented total hip surgery: the effects on hemodynamic, hemogasanalytic, and pulmonary shunt values

Introduction

During insertion of a cemented total hip arthroplasty, the rise of the intramedullary pressure in the femur, causes embolisation of fat and bone marrow into the pulmonary circulation. The goal of this study was to relate the embolic events observed by transesophageal echocardiography to the changes in hemodynamic, hemogasanalytic, and calculated pulmonary shunt values.

Material and methods

In this clinical trial entered 65 patients (>65 years). During the surgical period continually monitoring included ECG, measurement of invasive arterial pressure, pulsoximetric oxigen saturation, endtidal carbondioxid concentration as well as transesophageal echo-cardiography. A blinded observer graded embolic events from videotapes off-line after published criteria [1]. Hemogasanalysis was performed at defined points of the perioperative period. Preoperative clinical status of the patients was assessed according to the classification of the ASA. Pulmonary shunt-values were calculated with the formula of Ries et al [2].

Results

Cementation of the stem caused a cascade of fine emboli of less than 5 mm with an opacification of the right atrium and ventricle. In the same set of patients, after reduction of the hip joint, it was followed by macroemboli up to 3 cm (49 patients, 75%). No important embolic phenomena were observed during other surgical steps. Both embolic events were followed by changes in hemodynamics (increase in heart rate in 18%, P < 0.05; hypotension more than 20 mmHg in 62%) and blood gas parameters (paO₂ decreased for 7.7%, 41.4 mmHg; P < 0.05). PetCO₂ decreased for a mean of 2.9 mmHg (P < 0.05). Pulmonary shunt values increased after embolisation for a mean of 30.5% (P < 0.05). They did not turn back to baseline values in the postoperative period in patients classified ASA III and IV. A significant correlation (P < 0.05) was found between the clinical state before surgery and the duration and intensity of hemogasanalytic changes after insertion of the stem.

Conclusion

There is a correlation between embolic events quantified by transesophageal echo-cardiography and the grade of hemodynamic and haemogasanalytic changes of patients during cemented total hip arthroplasty. Patients with high anasthesiological risk can suffer severe cardiopulmonary complications from fat and bone marrow embolisation, that last even into the postoperative period and may cause intesive care treatment.