RECENT FINDINGS: Optimal antibiotic treatment is challenging in critically ill patients with nosocomial pneumonia; most dosing guidelines do not consider the altered physiology and illness severity associated with severe lung infections. Antibiotic dosing can be guided by plasma drug concentrations, which do not reflect the concentrations at the site of infection. The application of aggressive dosing regimens, in accordance to the antibiotic's pharmacokinetic/pharmacodynamic characteristics, may be required to ensure rapid and effective drug exposure in infected lung tissues.
SUMMARY: Conventional antibiotic dosing increases the likelihood of therapeutic failure in critically ill patients with nosocomial pneumonia. Alternative dosing strategies, which exploit the pharmacokinetic/pharmacodynamic properties of an antibiotic, should be strongly considered to ensure optimal antibiotic exposure and better therapeutic outcomes in these patients.
DESIGN: We conducted a systematic literature review and meta-analysis searching MEDLINE, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library from inception to April 1, 2017, for studies.
INTERVENTIONS: Mortality rates were compared between severely ill patients receiving piperacillin-tazobactam via prolonged infusion or intermittent infusion. Included studies must have reported severity of illness scores, which were transformed into average study-level mortality probabilities.
MEASUREMENTS AND MAIN RESULTS: Two investigators independently screened titles, abstracts, and full texts of studies meeting inclusion criteria for this systematic review and meta-analysis. Variables included author name, publication year, study design, demographics, total daily dose(s), average estimated creatinine clearance, type of prolonged infusion, prevalence of combination therapy, severity of illness scores, infectious sources, all-cause mortality, clinical cure, microbiological cure, and hospital and ICU length of stay. The review identified 18 studies including 3,401 patients who received piperacillin-tazobactam, 56.7% via prolonged infusion. Across all studies, the majority of patients had an identified primary infectious source. Receipt of prolonged infusion was associated with a 1.46-fold lower odds of mortality (95% CI, 1.20-1.77) in the pooled analysis. Patients receiving prolonged infusion had a 1.77-fold higher odds of clinical cure (95% CI, 1.24-2.54) and a 1.22-fold higher odds of microbiological cure (95% CI, 0.84-1.77). Subanalyses were conducted according to high (≥ 20%) and low (< 20%) average study-level mortality probabilities. In studies reporting higher mortality probabilities, effect sizes were variable but similar to the pooled results.
CONCLUSIONS: Receipt of prolonged infusion of piperacillin-tazobactam was associated with reduced mortality and improved clinical cure rates across diverse cohorts of severely ill patients.
OBJECTIVES: In this individual patient data meta-analysis of critically ill patients with severe sepsis, we aimed to compare clinical outcomes of those treated with continuous versus intermittent infusion of β-lactam antibiotics.
METHODS: We identified relevant randomized controlled trials comparing continuous versus intermittent infusion of β-lactam antibiotics in critically ill patients with severe sepsis. We assessed the quality of the studies according to four criteria. We combined individual patient data from studies and assessed data integrity for common baseline demographics and study endpoints, including hospital mortality censored at 30 days and clinical cure. We then determined the pooled estimates of effect and investigated factors associated with hospital mortality in multivariable analysis.
MEASUREMENTS AND MAIN RESULTS: We identified three randomized controlled trials in which researchers recruited a total of 632 patients with severe sepsis. The two groups were well balanced in terms of age, sex, and illness severity. The rates of hospital mortality and clinical cure for the continuous versus intermittent infusion groups were 19.6% versus 26.3% (relative risk, 0.74; 95% confidence interval, 0.56-1.00; P = 0.045) and 55.4% versus 46.3% (relative risk, 1.20; 95% confidence interval, 1.03-1.40; P = 0.021), respectively. In a multivariable model, intermittent β-lactam administration, higher Acute Physiology and Chronic Health Evaluation II score, use of renal replacement therapy, and infection by nonfermenting gram-negative bacilli were significantly associated with hospital mortality. Continuous β-lactam administration was not independently associated with clinical cure.
CONCLUSIONS: Compared with intermittent dosing, administration of β-lactam antibiotics by continuous infusion in critically ill patients with severe sepsis is associated with decreased hospital mortality.
OBJECTIVE: The objective of this study was to identify whether the epithelial lining fluid components inhibit amikacin-mediated bacterial killing.
METHODS: Two amikacin-susceptible (minimum inhibitory concentrations of 2 and 8 mg/L) Pseudomonas aeruginosa isolates were exposed in vitro to amikacin concentrations up to 976 mg/L in the presence of an acidic pH, mucin and/or surfactant as a means of simulating the epithelial lining fluid, the site of bacterial infection in pneumonia. Pharmacodynamic modelling was used to describe associations between amikacin concentrations, bacterial killing and emergence of resistance.
RESULTS: In the presence of broth alone, there was rapid and extensive (> 6 - log10) bacterial killing, with emergence of resistance identified in amikacin concentrations < 976 mg/L. In contrast, the rate and extent of bacterial killing was reduced (≤ 5 - log10) when exposed to an acidic pH and mucin. Surfactant did not appreciably impact the bacterial killing or resistance emergence when compared with broth alone for either isolate. The combination of mucin and an acidic pH further reduced the rate of bacterial killing, with the maximal bacterial killing occurring 24 h following initial exposure compared with approximately 4-8 h for either mucin or an acidic pH alone.
CONCLUSIONS: Our findings indicate that simulating the epithelial lining fluid antagonises amikacin-mediated killing of P. aeruginosa, even at the high concentrations achieved following nebulised administration.
METHODS: This was a two-centre randomised controlled trial of CI versus IB dosing of beta-lactam antibiotics, which enrolled critically ill participants with severe sepsis who were not on renal replacement therapy (RRT). The primary outcome was clinical cure at 14 days after antibiotic cessation. Secondary outcomes were PK/PD target attainment, ICU-free days and ventilator-free days at day 28 post-randomisation, 14- and 30-day survival, and time to white cell count normalisation.
RESULTS: A total of 140 participants were enrolled with 70 participants each allocated to CI and IB dosing. CI participants had higher clinical cure rates (56 versus 34 %, p = 0.011) and higher median ventilator-free days (22 versus 14 days, p MIC than the IB arm on day 1 (97 versus 70 %, p
DESIGN SETTING AND PARTICIPANTS: This international, multicentre, observational pharmacokinetic study will comprise adult critically ill patients prescribed antifungal agents including fluconazole, voriconazole, posaconazole, isavuconazole, caspofungin, micafungin, anidulafungin, and amphotericin B for the treatment or prophylaxis of invasive fungal disease. A minimum of 12 patients are targeted for enrolment for each antifungal agent, across 12 countries and 30 intensive care units to perform descriptive pharmacokinetics. Pharmacokinetic sampling will occur during two dosing intervals (occasions): firstly, between days 1 and 3, and secondly, between days 4 and 7 of the antifungal course, collecting three samples per occasion. Patients' demographic and clinical data will be collected.
MAIN OUTCOME MEASURES: The primary endpoint of the study is attainment of pharmacokinetic/pharmacodynamic target exposures that are associated with optimal efficacy. Thirty-day mortality will also be measured.
RESULTS AND CONCLUSIONS: This study will describe whether contemporary antifungal drug dosing achieves drug exposures associated with optimal outcomes. Data will also be used for the development of antifungal dosing algorithms for critically ill patients. Optimised drug dosing should be considered a priority for improving clinical outcomes for critically ill patients with fungal infections.
METHODS: We performed a prospective, observational, multinational, pharmacokinetic study in 29 intensive care units from 14 countries. We collected demographic, clinical, and RRT data. We measured trough antibiotic concentrations of meropenem, piperacillin-tazobactam, and vancomycin and related them to high- and low-target trough concentrations.
RESULTS: We studied 381 patients and obtained 508 trough antibiotic concentrations. There was wide variability (4-8-fold) in antibiotic dosing regimens, RRT prescription, and estimated endogenous renal function. The overall median estimated total renal clearance (eTRCL) was 50 mL/minute (interquartile range [IQR], 35-65) and higher eTRCL was associated with lower trough concentrations for all antibiotics (P < .05). The median (IQR) trough concentration for meropenem was 12.1 mg/L (7.9-18.8), piperacillin was 78.6 mg/L (49.5-127.3), tazobactam was 9.5 mg/L (6.3-14.2), and vancomycin was 14.3 mg/L (11.6-21.8). Trough concentrations failed to meet optimal higher limits in 26%, 36%, and 72% and optimal lower limits in 4%, 4%, and 55% of patients for meropenem, piperacillin, and vancomycin, respectively.
CONCLUSIONS: In critically ill patients treated with RRT, antibiotic dosing regimens, RRT prescription, and eTRCL varied markedly and resulted in highly variable antibiotic concentrations that failed to meet therapeutic targets in many patients.