Der Herzkathetertisch ist nicht der OP-Tisch

Zusammenfassung

Hintergrund

Bei herzchirurgischen Operationen ist ein aufwendiges Monitoring erforderlich. Wegen der Invasivität dieser Maßnahmen muss für jeden Patienten individuell eine Nutzen-Risiko-Abwägung erfolgen, von welchem Monitoring er profitiert und welches vielleicht sogar schädlich ist. Dies gilt insbesondere für den Einsatz des Pulmonalarterienkatheters (PAK), der in ausgewählten Fällen gerechtfertigt erscheint. So stellt die präoperative Diagnose „Pulmonalishochdruck“ in den S3-Leitlinien der DGAI eine Indikation zum perioperatives Monitoring mittels PAK dar.

Methode

In dieser retrospektiven Studie verglichen wir bei herzchirurgischen Patienten mit präoperativ erhöhten pulmonalarteriellen Druckwerten die Werte aus der Herzkatheteruntersuchung mit den intra- und postoperativ mittels eines PAK gemessenen.

Ergebnisse

Die prä- und intraoperativ bestimmten pulmonalarteriellen Druckwerte unterscheiden sich signifikant voneinander; die postoperativen Druckwerte entsprechen den intraoperativen. Das Verhältnis von systemischem zu pulmonalarteriellem Druck zeigt keine Unterschiede zu unterschiedlichen Messzeitpunkten.

Schlussfolgerung

Da sich die prä- und intraoperativ bestimmten pulmonalarteriellen Druckwerte unterscheiden, schlagen wir vor, intraoperativ zunächst echokardiographisch den pulmonalarteriellen Druck zu bestimmen und auf weitere Hinweise für einen pulmonalen Hypertonus zu achten, um dann individuell die Indikation für einen PAK zu prüfen.

Abstract

Background

Patients undergoing cardiac surgery need extensive and invasive monitoring, which needs to be individually adapted for each patient and requires a diligent risk-benefit analysis. The use of a pulmonary artery catheter (PAC) seems to be justifiable in certain cases; therefore, the preoperative diagnosis of pulmonary hypertension represents an indication for perioperative monitoring with PAC in the S3 guidelines of the German Society for Anesthesiology and Intensive Care Medicine (DGAI). In many cases, however, this preoperative diagnosis cannot be confirmed intraoperatively.

Objective

We wanted to find out whether this is just an impression or whether there actually are significant differences between preoperative, intraoperative and postoperative pulmonary artery pressures.

Material and methods

After obtaining ethical approval, we retrospectively compared the pulmonary pressures of cardiac surgery patients with an elevated pulmonary pressure during preoperative right heart catheterization with those obtained intraoperatively and postoperatively by means of a PAC. All patients with a preoperatively documented pulmonary artery pressure of 40 mmHg or above and an intraoperative use of a PAC during a 4-year period were included. Exclusion criteria were intracardiac shunts, cardiogenic shock, emergency procedures, pulmonary hypertension of non-cardiac origin and a time span of more than 1 year between right heart catheterization and surgery. We included 90 patients.

Results

In the whole group and in the subgroups (according to diagnosis, time elapsed between heart catheterization and operation and pulmonary pressure), there were significant differences between preoperative and intraoperative pulmonary and systemic pressures. Systemic and pulmonary artery pressures were significantly higher during preoperative catheterization than intraoperatively. The systemic systolic pressure/systolic pulmonary pressure ratio, however, remained constant. The intraoperative and postoperative systemic and pulmonary artery pressures showed no significant differences. As a normal ejection fraction does not exclude heart failure with preserved ejection fraction and as we did not have any information on this condition, we did not group the patients according to the ejection fraction.

Conclusion

An elevated pulmonary pressure obtained preoperatively during right heart catheterization is not indicative of an elevated pulmonary pressure either intraoperatively or postoperatively. There are various explanations for the differences (e.g., different physiological and pathophysiological settings, such as sedation with potential hypercapnia versus anesthesia with vasodilation when measured; newly prescribed medication coming into effect between the right heart catheterization and surgery; intraoperative positioning). Even though the inherent risks of a PAC seem to be low, we recommend refraining from using a PAC in patients with a once documented elevated pulmonary pressure by default. As an alternative we suggest estimating the pulmonary pressure by transesophageal echocardiography (TEE) as an aid to decide whether the patient will benefit from the use of a PAC. Especially if it is not possible to identify tricuspid valve regurgitation for determining the peak gradient, it is helpful to check for additional signs of pulmonary hypertension. But we also have to bear in mind that in the postoperative period only a PAC can provide continuous measurement of pulmonary pressure.