Epidemiologic, clinical characteristics, and risk factors for adverse outcome in multiresistant gram-negative primary bacteremia of critically ill patients.

BACKGROUND: Characteristics and burden of primary bacteremia because of multidrug-resistant (MDR) gram-negative bacteria (GNB) in intensive care unit (ICU) patients remain understudied. METHODS: A cohort study of patients with primary MDR GNB-related bacteremia from the ICU of a tertiary Greek hospital during a 3-year period was conducted for recognition of clinical characteristics and risk factors for adverse outcome. A case-control study was further performed to evaluate risk factors for development of MDR GNB-related primary bacteremia. RESULTS: Fifty monomicrobial episodes of primary bacteremia because of Klebsiella pneumoniae (n = 20), Acinetobacter baumannii (n = 18), and Pseudomonas aeruginosa (n = 12) were recorded. The presence of diabetes mellitus was the only significant risk factor for development of MDR GNB-related primary bacteremia. Most episodes (78%) were ICU acquired in patients with prolonged mechanical ventilation and previous hospitalization in the ward. Mortality was 47.6% vs 19% of controls, P = .01. Mortality was higher in recurrent bacteremia (62.5%). Mortality was statistically associated with age (P = .002) and degree of multiorgan dysfunction expressed by sequential organ failure assessment score on day of bacteremia documentation (P = .001). CONCLUSION: Critically ill patients with MDR GNB-related primary bacteremia present significant mortality mainly associated with age and multiorgan failure. A baumanii bacteremia confers significant mortality compared with the benign course of K pneumoniae in such settings. Diabetes mellitus is a risk factor for development of such episodes, which may, in part, be general ward acquired, underlining the need for expanded vigilance.

Pharmacokinetic evaluation of colistin sodium.

IMPORTANCE OF THE FIELD: Although colistin has recently played a key role in the treatment of nosocomial infections due to multidrug resistant Gram-negative pathogens, there is a lack of clinical studies examining colistin pharmacokinetics (PKs) in humans. This refers to all routes of colistin administration in clinical practice. Colistin PK data are also limited in critically ill patients. AREAS COVERED IN THIS REVIEW: Literature search took into account data dealing with colistin PK obtained from animal studies performed during previous decades (1970s, 1980s and 1990s) and from recent human studies performed during the last decade. WHAT THE READER WILL GAIN: Valuable information on pharmacodynamics (PD)/PK of colistin used in the treatments of nosocomial infections due to multidrug resistant Gram-negative pathogens, mostly Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. A better understanding of PKs could offer significant improvement of colistin use in humans, especially optimization of colistin doses in different routes of administration in order to maximize clinical efficacy and minimize adverse effects and rate of resistance. TAKE HOME MESSAGE: There is a lack of human studies on colistin PK and PD. Significant PD parameters best predicting colistin efficacy and their optimal values such as C(max):MIC ratio, AUC/MIC and T > MIC have not yet been clearly defined. It should be noted that further investigation on colistin PK/PD in vitro and in vivo models is required.

Multidrug-resistant Gram-negative infections: the use of colistin.

The emergence of nosocomial infections due to multidrug-resistant Gram-negative bacteria led to the revival of 'forgotten' antibiotics, such as polymyxins. Colistin, mainly colistimethate sodium (polymyxin E), has been predominantly used. Recent studies suggest that colistin administered as monotherapy or combination therapy is an effective and safe antimicrobial agent for multidrug-resistant Gram-negative bacteria infections. The reported colistin nephrotoxicity is 20% or lower. Although colistin is commonly administered intravenously, it can also be administered via inhalation for pneumonia/ventilator-associated pneumonia treatment or by the intraventricular/intrathecal route for meningitis/ventriculitis treatment. Randomized controlled trials are needed to answer clinical questions such as the appropriate colistin dose, to compare colistin monotherapy with combination therapy, and to determine the exact therapeutic role of aerosolized or intrathecal/intraventricular administration of colistin.

Predictors of early postoperative atrial fibrillation after off-pump myocardial revascularization.

OBJECTIVE: : We determined the incidence and the predisposing factors of atrial fibrillation (AF) after aorta nontouch coronary artery bypass grafting without extracorporeal circulation. METHODS: : From February 2001 to November 2005, 1359 patients (1159 men, 85.3%) of mean (±SD) age 64.8 (±9.8) years, who underwent off-pump coronary artery bypass grafting (OP-CAB), were prospectively enrolled. Demographics, perioperative data, and comorbidities were recorded in all patients. A 24-hour rhythm monitoring was performed in all patients until hospital discharge. RESULTS: : Among 1359 patients, 273 (20.1%) had development of atrial fibrillation in the early postoperative period. Patients with AF had higher mean (±SD) age, 68.3 (±8.8) years, compared with control subjects [63.9 (±9.9)] (P ≤ 0.0005). Univariate analysis showed that apart from age, history of arterial hypertension (P ≤ 0.02), chronic obstructive pulmonary disease (P ≤ 0.02), and the use of bilateral internal mammary arteries (P ≤ 0.01) were predisposing factors for the development of AF. Logistic regression analysis showed that age, history of arterial hypertension, and the use of bilateral internal mammary arteries were predisposing factors for early postoperative AF after OP-CAB. CONCLUSIONS: : Atrial fibrillation occurred in approximately 20% of patients undergoing OP-CAB, mainly in older patients with arterial hypertension who received bilateral internal mammary artery grafts.

External reshaping of the left ventricle in off-pump surgery.

BACKGROUND: : Dyskinetic areas of the lateral and inferior left ventricular (LV) wall are frequently encountered in patients with coronary artery disease. In clinical practice, all of the techniques described for the restoration of shape and function of the LV require cardiopulmonary bypass. A new technique of LV external reshaping that aims to obtain a near-normal ventricular conical shape is described. This technique is performed during an off-pump coronary artery bypass graft (CABG) operation. It is used mainly on the inferior and lateral walls of the ventricle, but also on the anterolateral wall when warranted. This technique can be considered an alternative to classic aneurysmectomy in high-risk cases. METHODS: : All patients underwent total arterial revascularization without aortic manipulation. Intraoperative transesophageal echocardiography was used in all cases to define the dilated akinetic/dyskinetic area. This area was effectively plicated using interrupted mattress sutures reinforced with Teflon felt or pericardial strips. This technique allows near normalization of the geometry of the ventricle and LV end-diastolic volume reduction. In cases of preexisting mitral regurgitation (MR), a reduction of the MR was observed after lateral wall restoration. From September 2002 to April 2005, the external reshaping technique was applied on 56 cases among 949 off-pump CABG cases (5.9%). A detailed transthoracic echocardiogram was obtained preoperatively. The mean ejection fraction of all enrolled patients was 31.2 ± 7%. The location of the plication was: lateral wall in 22, inferior wall in 16, and anterolateral wall in 18. The average number of coronary anastomoses was 2.6. Twelve patients were found to have 2-3+ MR. All patients were followed up during a period of 35 months. RESULTS: : One patient died due to severe right ventricular dysfunction. Seven patients developed atrial fibrillation, and one had ventricular tachycardia. During the follow-up period, we observed a reduction of left ventricular end-diastolic diameter and a parallel augmentation of ejection fraction (mean 42.2 ± 4%). The ventricular cavity's architecture was normalized. Among the 12 patients with MR, an improvement of regurgitation was noted in 10 (from 2-3+ to 1-2+). One patient died during the follow-up period, and 1 patient required reoperation due to persistent severe MR. CONCLUSIONS: : The external reshaping of the LV during beating heart surgery is technically feasible, has promising results, and can be performed without major complications.