Pruritus: a useful sign for predicting the haemodynamic changes that occur following administration of vancomycin

Abstract

IntroductionVancomycin is among the most effective antibiotics for treatment of methicillin-resistant Staphylococcus aureus infections [1][2][3][4], and it is widely used prophylactically in cardiac surgery [5][6][7]. Among the adverse effects of vancomycin (apart from nephrotoxicity and ototoxicity), anaphylactoid reactions may occur, which manifest clinically as cutaneous rash, pruritus ('red man' syndrome), hypotension and broncospasm [4,8,9]. These reactions are caused by histamine release, and are not mediated by an immunological mechanism [10,11].In our cardiosurgical center vancomycin is administered prophylactically before induction of anaesthesia in all patients undergoing open-heart surgery, and in some such patients we CI = cardiac index; PaO 2 = arterial oxygen tension; PVRI = pulmonary vascular resistance index; Qsp/Qt = shunt fraction; SVI = stroke volume index; SVRI = systemic vascular resistance index. AbstractIntroduction The aim of this study was to investigate the haemodynamic changes that follow the appearance of pruritus during vancomycin administration. Methods We studied 50 patients scheduled for coronary artery bypass surgery, and we compared data from patients who exhibited pruritus with those from patients who did not. After the monitoring devices had been positioned, vancomycin (15 mg/kg) was continuously infused at a constant rate over 30 min, before induction of anaesthesia. Haemodynamic profiles were recorded before vancomycin infusion (time point 1); at 15 (time point 2) and 30 min (time point 3) after the beginning of vancomycin infusion; and 15 min after vancomycin infusion had been stopped (time point 4). At each time arterial and mixed venous blood samples were drawn to calculate the shunt fraction (Qsp/Qt). Results In patients who exhibited pruritus (group A, n = 17) at time point 3 versus time point 1, systemic vascular resistance index (SVRI) and arterial oxygen tension (PaO 2 ) decreased significantly; cardiac index (CI), stroke volume index (SVI) and Qsp/Qt increased significantly; and mean systemic pressure and heart rate were stable. Those changes were observed only in patients not treated with a β-blocker before surgery, whereas no change occurred in patients treated with the drug. In the patients who were free from pruritus (group B, n = 28), we did not observe any significant change. Conclusion The appearance of pruritus during vancomycin administration indicates that SVRI is declining, thus exposing the patient to risk for hypotension. Therapy with a β-blocker appears to confer protection against this hemodynamic reaction.

Можливості Ванкоміцину Вчора І Сьогодні

“…Гіпотензія іноді спричиняє занепокоєння, якщо виникає під час анестезії після застосування ванкоміцину для хірургічної профілактики. Виявлено, що від гіпотензії, спричиненої інфузією ванкоміцину, перед операцією захищає терапія β-адреноблокаторами [5].…”