Role of Clinical Pharmacists in Antimicrobial Therapy for Patients with Septic Shock in the ICU

Introduction

Septic shock remains one of the most challenging conditions encountered in intensive care units (ICUs) and it is a major cause of morbidity and mortality worldwide. It is characterized by a dysregulated host response to infection that leads to systemic inflammation, profound circulatory and metabolic abnormalities, and, ultimately, tissue hypoperfusion and multi-organ dysfunction [1,2]. The rapid progression of septic shock demands immediate and precise therapeutic interventions, particularly in antimicrobial management. Despite advances in clinical guidelines, antimicrobial therapy in ICU settings often relies on empirical regimens shaped by clinician experience rather than individualized treatment strategies [3]. This empirical approach, although often necessary in urgent scenarios, can result in inappropriate antibiotic use, delayed de-escalation, or under-recognition of resistant organisms. This approach is further complicated by the increasing prevalence of multidrug-resistant organisms, variability in infection sources, and patient-specific pharmacokinetics, which together contribute to therapeutic failure, adverse drug reactions, and escalating healthcare costs [4]. Moreover, the dynamic pathophysiology of critically ill patients – including altered drug metabolism, fluctuating organ function, and complex infection profiles – requires continuous monitoring and adjustment of antimicrobial regimens [5]. These challenges underscore the need for more robust and targeted antimicrobial stewardship in critical care.

Clinical pharmacists, as integral members of multidisciplinary ICU teams, bring specialized expertise in optimizing anti-infective therapies. Their interventions – such as dose adjustments based on pharmacokinetic/pharmacodynamic (PK/PD) parameters, infection severity, and culture results – can reduce inappropriate antibiotic use, limit resistance development, and improve patient outcomes [5,6]. Additionally, clinical pharmacists are well-positioned to monitor and prevent adverse drug reactions, promote protocol adherence, and support evidence-based de-escalation practices [7]. Despite growing evidence supporting pharmacist-led interventions in general antimicrobial stewardship programs, their direct impact on outcomes in septic shock remains underexplored and underreported in the literature.

Current gaps exist in clearly demonstrating the measurable benefits of pharmacist integration in ICU settings for septic patients, particularly regarding outcome-specific indicators such as changes in oxygen metabolism, systemic inflammation, and drug safety. Furthermore, the extent to which pharmacist intervention can rationalize the use of broad-spectrum antimicrobials and improve patient-specific treatment remains an area of active inquiry. This study aimed to investigate the clinical value of integrating clinical pharmacists into the antimicrobial management of ICU patients with septic shock. Specifically, it evaluated the effects of pharmacist-guided interventions on antibiotic utilization patterns (with particular attention to carbapenems, quinolones, and third-generation cephalosporins), markers of tissue oxygen metabolism (ScvO2 and lactic acid), systemic inflammatory response (IL-1β and PCT), and the incidence of adverse drug reactions. By addressing gaps in personalized antimicrobial stewardship in septic shock, this study seeks to contribute to more effective and safer critical care practices.

Material and Methods

ETHICS APPROVAL:

The study was approved by the Ethics Committee of the General Hospital of Ningxia Medical University, Cardio-Cerebral Vascular Disease Hospital, Yinchuan, Ningxia Hui Autonomous Region, China under approval number 2021-NING-093. Informed consent was obtained from all participants or their legal representatives prior to enrollment.

GENERAL INFORMATION:

A total of 94 ICU patients diagnosed with septic shock between May 2021 and June 2023 were enrolled and randomly assigned to 2 groups using the envelope method. The randomization sequence was manually prepared using a random number table by an independent investigator not involved in patient care. Opaque, sealed, and sequentially numbered envelopes were used to ensure allocation concealment. The envelopes were opened only after patient enrollment to maintain the integrity of the assignment process. The control group comprised 47 patients (28 males, 19 females), aged 42–74 years (mean 61.25±6.29), with a body mass index (BMI) of 18.4–29.1 kg/m² (mean 22.24±3.41). Infection types included pulmonary (n=18), urinary tract (n=17), abdominal (n=10), and other infections (n=2). The observation group also included 47 patients (29 males, 18 females), aged 41–73 years (mean 62.19±6.32), with a BMI of 18.2–29.5 kg/m² (mean 22.31±3.46). Infection types were pulmonary (n=15), urinary tract (n=18), abdominal (n=11), and others (n=3). No significant differences in baseline characteristics were observed between the 2 groups (P>0.05). Blinding of ICU physicians and pharmacists was not feasible due to the nature of the intervention. However, data analysts and outcome assessors were blinded to the group assignments to reduce detection bias. The ICU physician team initiating antibiotic therapy in the control group comprised critical care physicians and general internists; infectious disease specialists were not routinely involved.

INCLUSION AND EXCLUSION CRITERIA:

Patients were included in the study if they were diagnosed with septic shock and admitted to the ICU of the hospital [8], received anti-infective therapy without any known history of drug allergy, and had peripheral venous blood samples collected before and after treatment. Blood cultures were collected at admission to guide therapy; however, confirmed bacteremia was not required for inclusion.

Exclusion criteria included patients with autoimmune diseases or diagnosed malignancies, those who had recently received glucocorticoids or other immunosuppressive agents, and patients who either died within 3 days after admission or had concurrent systemic infectious diseases.

TREATMENT METHODS:

The control group received standard anti-infective therapy, including symptomatic and supportive care, guided by bacterial culture, drug sensitivity testing, and clinical experience [9].The observation group received pharmacist-led anti-infective therapy, which included:

ANTIBIOTIC UTILIZATION:

Usage rates of carbapenems, quinolones, β-lactamase inhibitors, third-generation cephalosporins, cephalosporins, glycopeptides, antifungal agents, nitroimidazoles, and aminoglycosides.

TISSUE OXYGEN METABOLISM AND INFLAMMATORY MARKERS: We assessed central venous oxygen saturation (ScvO2) via oximetry [10], blood lactic acid (Lac) by spectrophotometry [11], interleukin-1β (IL-1β) via ELISA [12], and procalcitonin (PCT) via radioimmunoassay [13]. ScvO2 and Lac were measured using central venous samples, as all patients had central lines placed for ICU monitoring. Central venous parameters were preferred over arterial blood gas due to their routine integration in sepsis management and strong clinical correlation with tissue perfusion and metabolic status.

DRUG SAFETY:

We recorded incidences of rash, nausea/vomiting, drug fever, epilepsy, and hepatic and renal dysfunction. Adverse drug reactions were monitored prospectively through daily assessments by the clinical pharmacist and attending physicians. All adverse events were recorded using a standardized ADR reporting form. Severity grading and causality assessment were performed using institutional pharmacovigilance protocols aligned with national ADR reporting standards.

STATISTICAL ANALYSIS:

Data were analyzed using SPSS version 26.0. Categorical variables were compared using the χ² test and expressed as n (%). Continuous variables were analyzed using the t-test and presented as mean±standard deviation. A P value <0.05 was considered statistically significant.

Results

COMPARISON OF ANTIMICROBIAL AGENT UTILIZATION BETWEEN THE 2 GROUPS:

The distribution of antimicrobial agents differed significantly between the 2 groups. The observation group used fewer carbapenems (23.40% vs 40.43%) and quinolones (10.64% vs 31.91%) compared to the control group (P<0.05 for both), while third-generation cephalosporin use was notably higher (34.04% vs 6.38%, P=0.010).

No significant differences were observed in the use of other agents, including cephalosporins (non-third-generation), glycopeptides, antifungals, β-lactamase inhibitors, nitroimidazoles, and aminoglycosides (P>0.05) (Table 1). These outcomes highlight the impact of pharmacist-led interventions on optimizing antibiotic selection by reducing the reliance on broad-spectrum agents and promoting narrower-spectrum, evidence-based alternatives.

COMPARISON OF TISSUE OXYGEN METABOLISM AND INFLAMMATORY MARKERS:

Following treatment, the observation group exhibited significantly better outcomes across all parameters. ScvO2 was higher (69.84±6.12% vs 65.47±5.54%), while levels of Lac (1.85±0.31 vs 2.69±0.62 mmol/L), IL-1β (401.53±16.87 vs 496.36±24.34 μg/mL), and PCT (9.41±1.52 vs 13.29±2.65 ng/mL) were all lower in the observation group compared to the control group (P<0.05 for all) (Table 2) This indicates that the pharmacist-guided strategy not only improved antimicrobial precision but also enhanced tissue oxygenation and mitigated systemic inflammation more effectively.

COMPARISON OF ADVERSE DRUG REACTIONS:

Adverse drug reactions (ADRs) were significantly lower in the observation group (4.26%) than in the control group (19.15%) (P=0.025). The pharmacist-led group reported 2 cases (1 nausea/vomiting, 1 epilepsy), while the control group experienced 9 events, including rash (n=2), nausea/vomiting (n=2), drug fever (n=2), epilepsy (n=2), and hepatic/renal dysfunction (n=1). This reduction reflects the direct influence of the pharmacist’s role in dose adjustment, proactive monitoring, and early identification of high-risk combinations, as detailed in the Methods section (Table 3).

Discussion

Septic shock is a life-threatening complication of infection characterized by systemic inflammatory response syndrome, increased capillary permeability, reduced effective circulating blood volume, and in severe cases, microcirculatory dysfunction and multi-organ failure [14]. The rapid progression and complexity of septic shock demand timely and individualized therapeutic approaches. It has been reported that delayed or inadequate treatment can result in multiple organ dysfunction syndrome (MODS), which is a leading cause of death among ICU patients [15].

Antimicrobial therapy remains the cornerstone of treatment in septic shock. However, empirical antibiotic use – often guided by clinician experience – poses risks of irrational prescribing, especially in the context of increasing multidrug-resistant organisms and heterogeneous infection sites [16]. In our study, integrating clinical pharmacists into the antimicrobial stewardship process resulted in a more rational and pathogen-directed antibiotic utilization pattern. Specifically, we observed a significant reduction in the use of broad-spectrum agents such as carbapenems and quinolones, alongside increased utilization of third-generation cephalosporins. These findings align with the pharmacist-led protocol that emphasized tailoring therapy based on infection site, resistance patterns, PK/PD profiles, and individual patient response [17,18].

The improved antibiotic selection likely contributed to the enhanced physiological outcomes observed in the pharmacist-intervened group, including significantly higher ScvO2 and lower levels of Lac, IL-1β, and PCT. These indicators reflect improved tissue oxygenation and reduced systemic inflammation, consistent with effective infection control and timely therapeutic adjustment [19,20]. Such findings underscore the clinical utility of pharmacist involvement in optimizing both antimicrobial efficacy and host recovery.

Furthermore, our data demonstrated a markedly lower incidence of adverse drug reactions (4.26% vs 19.15%) in the pharmacist-led group. This outcome reflects the added value of pharmacist oversight in dosing, monitoring renal and hepatic function, preventing drug–drug interactions, and guiding safe administration practices. These results are consistent with previous studies that found clinical pharmacist participation was associated with improved drug safety and reduced treatment-related complications in ICU populations [21,22]. Our findings contribute to the growing body of evidence advocating for multidisciplinary approaches to antimicrobial stewardship, particularly in critically ill populations. By improving both treatment precision and safety, clinical pharmacists represent a vital resource in managing complex sepsis cases [23].

This study has several limitations that should be considered when interpreting the findings. First, the sample size was relatively small and limited to a single center, which may restrict the generalizability of the results. Future research should include multicenter randomized controlled trials to validate these findings across diverse ICU populations. Second, although the envelope method ensured random allocation, blinding of clinicians and pharmacists was not feasible due to the nature of the intervention, potentially introducing performance or observer bias. Third, the study primarily assessed short-term outcomes, such as antimicrobial utilization, inflammatory markers, and adverse drug reactions. Long-term clinical endpoints – such as ICU length of stay, duration of mechanical ventilation, and mortality – were not evaluated and warrant investigation in future studies. Fourth, therapeutic drug monitoring (TDM) was not performed due to institutional limitations and the unavailability of real-time drug concentration assays for the antibiotics used, which may have limited the precision of dosing adjustments. Lastly, the study did not include a cost-effectiveness analysis, which is crucial for assessing the feasibility and scalability of pharmacist-led interventions, particularly in resource-limited settings.

Despite these limitations, the study provides meaningful insight into the clinical value of pharmacist integration in ICU antimicrobial management. By promoting rational antibiotic use, improving patient outcomes, and reducing complications, clinical pharmacists play a crucial role in optimizing care for patients with septic shock.

Conclusions

In conclusion, clinical pharmacist intervention in the anti-infective management of ICU patients with septic shock significantly enhances the rationality of antibiotic use, as evidenced by the reduced use of carbapenems and quinolones and increased use of third-generation cephalosporins. It also improves oxygen metabolism and inflammatory profiles, and promotes drug safety by reducing the incidence of adverse drug reactions. These findings underscore the value of pharmacist-guided antimicrobial stewardship in optimizing both therapeutic outcomes and patient safety. However, the study’s limitations – including its single-center design, relatively small sample size, and short follow-up period – should be acknowledged. Future multicenter studies are warranted to validate these results, evaluate long-term outcomes, and assess cost-effectiveness in diverse healthcare settings. Given the positive impact observed, this approach is recommended for broader adoption in critical care settings as a practical strategy to improve sepsis management and antibiotic stewardship.