Clinical diagnostic accuracy of suspected sources of bacteremia and its effect on mortality

BACKGROUND

Although much has been written about bacteremia, evidence of the clinical diagnostic accuracy of bacteremia sources in the absence of microbiological results and the impact of diagnostic accuracy on mortality is scarce.

METHODS

This is a retrospective study of bacteremia episodes over a 2-year period at a general hospital in Madrid. Congruence analyses between clinically presumed and definite sources, acquisition, causative organism, empirical treatment and progression to death were performed.

RESULTS

The study included 323 bacteremia episodes. Clinicians' diagnostic accuracy was higher for gastrointestinal (88.8%; 95% CI: 79%-84%), respiratory (93.9%; 95% CI: 79%-99%) and urinary tract sources (83.6%; 95% CI: 75%-89%) and lower for skin and soft tissues (77.2%; 95% CI: 54%-92%) and, notably, intravascular sources (56%; 95% CI: 39%-71%). Overall, a non-significant (3.45%; 95% CI: -0.6%-13.5%, p=0.47) increase in mortality was observed in the incorrectly suspected bacteremia source group. Mortality related to a definitive source was significantly higher when an intravascular origin was not suspected, resulting in a 26% increase in mortality (95% CI: 1%-52%, p=0.03). Differences in mortality related to inaccurate source assumptions were non-significant when the definitive bacteremia sources were gastrointestinal, urinary, respiratory, skin and soft tissues or unknown. Mortality in the group receiving appropriate empirical antimicrobial treatment was 10.6% compared with 19.7% mortality in the group receiving inappropriate empirical antimicrobial treatment (OR 2; 95% CI: 1.01-4.25).

CONCLUSIONS

The diagnostic accuracy of bacteremia sources is high in all but intravascular sources. A non-suspected intravascular source and inappropriate empirical treatment are related to a higher mortality.

Assessment of acute right ventricular dysfunction induced by right coronary artery occlusion using echocardiographic atrioventricular plane displacement

Right ventricular (RV) systolic function analysis by echocardiography has traditionally required RV endocardial border definition with subsequent tracing and is often inaccurate or impossible in technically poor studies. The atrioventricular plane displacement (AVPD) method attempts to use the descent of the tricuspid annular ring, a reflection of the longitudinal shortening of the right ventricle, as a surrogate marker for RV systolic function. We hypothesized that RV ischemia induced during right coronary artery occlusion proximal to the major right ventricular branches would result in severe right ventricular systolic dysfunction detectable by the AVPD method. During this pilot study, seven patients undergoing elective proximal RCA angioplasty had echocardiographic measurement of RV AVPD performed at baseline (i.e., immediately prior to RCA balloon inflation), during the last 30 seconds of first RCA balloon inflation, and at 1 minute after balloon deflation (recovery). Lateral and medial RV AVPD were significantly reduced from baseline values during intracoronary balloon inflation. (Lateral: 2.45 cm +/- 0.22 vs 1.77 cm +/- 0.13, P < 0.001; medial: 1.46 cm +/- 0.37 vs 1.28 cm +/- 0.32, P < 0.05). Additionally, lateral and medial RV AVPD significantly returned towards baseline values during recovery. (Lateral: 2.39 cm +/- 0.20, P < 0.001; medial: 1.58 cm +/- 0.27, P = 0.01). At baseline, all lateral RV AVPD values were > 2.0 cm, whereas during balloon inflation all were < 2.0 cm. No such clear distinction was found in medial RV AVPD values. Proximal RCA angioplasty is associated with a significant reduction in lateral and medial RV AVPD. Thus RV AVPD may serve as a marker for RV systolic dysfunction.

Spontaneous intramural atrial hematoma presenting as a left atrial mass

We describe an unusual case of spontaneously occurring intramural atrial hematoma with no communication with either atrium. The diagnosis of left atrial mass was made from transthoracic echocardiography. Subsequent examination with transesophageal echocardiography confirmed a large mass essentially filling the whole left atrium but failed to provide an etiologic diagnosis, which was eventually made at surgery.