Extended vs. Intermittent Beta-Lactam Infusion in ICU Sepsis

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. Septic shock should be considered a subset of sepsis in which underlying circulatory, cellular, and metabolic abnormalities significantly increase mortality risk compared to sepsis alone.

Beta-lactam antibiotics exhibit broad-spectrum activity against most Gram-positive and Gram-negative bacteria, making them a key component of sepsis treatment. Their bactericidal effects are time-dependent, meaning efficacy depends on maintaining free drug concentrations above the minimum inhibitory concentration of the target pathogen for an optimal duration.

In clinical practice, beta-lactams are typically administered via intermittent infusion. However, critically ill patients often experience altered pharmacokinetics due to changes in renal clearance, protein binding, fluid balance, and volume distribution. This variability can lead to unpredictable drug concentrations, increasing the risk of subtherapeutic antibiotic exposure.

Existing studies suggest that continuous infusion may enhance beta-lactam efficacy by maintaining drug concentrations above the minimum inhibitory concentration for longer periods, optimizing pharmacokinetic and pharmacodynamic targets. Some meta-analyses and small randomized controlled trials report reduced mortality and improved clinical cure rates with continuous infusion, while others show no significant difference. However, differences in dosing regimens, patient populations, and pharmacokinetic variability in critically ill patients make it difficult to draw firm conclusions.

Inclusion criteria

• Aged: 18 - 65
• Patients admitted to critical care unit diagnosed with pneumonia or urinary tract infection with two of the following:

• Temperature: over 38 degree celsius
• Heart rate: over 100 beats per minute
• Respiratory rate: over 20 breaths per minute
• leucocyte count over than 12000 or less than 4000 microlitres or over 10% immature forms or bands
• Patients with positive sputum or urine cultures

Exclusion criteria

• Hypersensitivity to Beta-lactams
• Pregnancy
• Very low probability of survival using APAACHE II score > 34 points.
• Immunodeficency or taking immunosuppressive medications
• Acute or chronic renal failure with creatinine clearance less than 30 ml/min according to Cockcroft-Gault formula.