Antibiotic related acute kidney injury in patients treated for open fractures

What is the right gentamicin dose for multiple trauma patients? A Monte Carlo simulation exploration study

Background

The appropriate dose of gentamicin is important to prevent and treat infections. The study aimed to determine the optimal dose of gentamicin to achieve the probability of pharmacokinetic/pharmacodynamic (PK) targets for efficacy and safety in multiple trauma patients.

Methods

PK parameters of gentamicin in multiple trauma patients were gathered to develop a one-compartment PK model for prediction. The Monte Carlo simulation method was performed. The 24-h area under the concentration time curve to the minimum inhibitory concentration ratio (AUC24h/MIC) ≥50 was defined for the infection prevention target. AUC24h/MIC ≥110 or the maximum serum concentration to MIC ratio ≥8-10 was for the treatment of serious Gram-negative infection target. The risk of nephrotoxicity was the minimum serum concentration ≥2 mg/L. The optimal dose of gentamicin was determined when the efficacy target was >90% and the risk of nephrotoxicity was lowest.

Results

The optimal gentamicin dose to prevent infection when the MIC was <1 mg/L was 6-7 mg/kg/day. A higher dose of gentamicin up to 10 mg/kg/day could not reach the target for treating serious Gram-negative infection when the expected MIC was ≥1 mg/L. The probability of nephrotoxicity was minimal at 0.2-4% with gentamicin doses of 5-10 mg/kg/day for 3 days.

Conclusions

Once daily gentamicin doses of 6-7 mg/kg are recommended to prevent infections in patients with multiple trauma. Gentamicin monotherapy could not be recommended for serious infections. Further clinical studies are required to confirm our results.

Risk of Acute Kidney Injury and Fracture-Related Infection After Antibiotic Prophylaxis With Piperacillin-Tazobactam in Open Fractures

OBJECTIVES

To evaluate the effects of prophylactic piperacillin-tazobactam (PT) on inpatient acute kidney injury (AKI) and fracture-related infection (FRI) in patients with open fractures.

SETTING

The study was conducted at a Level 1 trauma center.

PATIENTS

We reviewed 358 Gustilo-Anderson type II and III open fractures at our institution from January 2013 to December 2017.

INTERVENTION

Administration of PT (the PT group) or antibiotics other than PT (the historical control group) during the first 48 hours of arrival for open fracture antibiotic prophylaxis.

MAIN OUTCOME MEASUREMENTS

The main outcome measurements were rates of inpatient AKI and FRI within six months after definitive fixation.

RESULTS

There were 176 patients in the PT group and 182 patients in the historical control group. The PT group had worse American Society of Anesthesiologists class ( P = 0.004) and injury severity scores ( P < 0.001), a higher average number of debridements before closure/coverage ( P = 0.043), and higher rates of gross soil contamination ( P = 0.049) and staged procedures ( P = 0.008) compared with the historical control group.There was no difference in the rate of AKI between the PT and historical control groups (5.7% vs. 2.7%, P = 0.166) nor when stratified by Gustilo-Anderson fracture classification (type II: 5.8% vs. 3.6%, P = 0.702; type III: 5.6% vs. 2.0%, P = 0.283). There was no significant difference in the rate of FRI between the PT and historical control groups (23.6% vs. 19.6%, P = 0.469).

CONCLUSION

The use of PT in prophylactic antimicrobial treatment in patients with Gustilo-Anderson type II and III open fractures does not increase the rate of AKI or FRI. We believe PT can be used as an effective monotherapy in these patients without an increased risk of renal injury, but future investigations are necessary.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Cefazolin Monotherapy Versus Cefazolin Plus Aminoglycosides for Antimicrobial Prophylaxis of Type III Open Fractures

BACKGROUND

There are conflicting recommendations between organizations regarding aminoglycoside use for the prophylaxis of type III open fractures.

STUDY QUESTION

To compare cefazolin monotherapy versus cefazolin plus aminoglycoside therapy for prophylaxis of type III open fractures in trauma patients.

STUDY DESIGN

This was a multicenter, retrospective, cohort study conducted in 3 academic medical centers in the United States. Consecutive adult trauma patients with type III open fractures between January 2014 and September 2016 were included. Patients were divided into 2 groups: (1) cefazolin monotherapy versus (2) cefazolin plus aminoglycoside.

MEASURES AND OUTCOMES

The primary outcome measure was the occurrence of infection at the open fracture site. The secondary outcome measure was the occurrence of acute kidney injury.

RESULTS

There were 134 patients included in the study cohort. Of these, 39 received cefazolin monotherapy and 95 received cefazolin plus aminoglycoside. Overall, the mean age was 39 ± 15 years, 105 (78%) were male, and the most common fracture location was tibia/fibula (n = 74, 56%). Infection at the open fracture site occurred in 6 of 39 patients (15%) in the cefazolin monotherapy group and 15 of 95 patients (16%) in the cefazolin plus aminoglycoside group (P = 1.000). Acute kidney injury occurred in 0 of 39 (0%) in the cefazolin monotherapy group and 1 of 95 (1%) in the cefazolin plus aminoglycoside group (P = 1.000).

CONCLUSIONS

Cefazolin monotherapy may be appropriate for antimicrobial prophylaxis of type III open fractures in trauma patients.

Piperacillin/Tazobactam versus Tobramycin-Based Antibiotic Prophylaxis for Type III Open Fractures

Background: Type III open fractures are associated with an infection rate as high as 50%. The optimal antibiotic for open fracture prophylaxis remains unclear, and the literature comparing the safety and efficacy of different antibiotic regimens is limited. The aim of this study was to compare the composite adverse events (AEs) in patients before and after a change in prophylactic antibiotic management for these injuries from a tobramycin- to a piperacillin/tazobactam-based regimen. Methods: This was a retrospective single-center cohort study of patients with Type III open fractures admitted from January 2010 to December 2016. Patients were included if they received either tobramycin plus cefazolin or clindamycin or piperacillin/tazobactam for fracture prophylaxis. The primary outcome was the rate of composite AEs, which included nephrotoxicity, surgical site infection (SSI), and hospital re-admission with surgical intervention. Secondary outcomes included the rate of SSI within 30 and 60 days after injury. Data were analyzed using the Student t-, Mann-Whitney U, and Fisher exact tests. Results: Eighty-five patients were included. There were 29 events in the tobramycin group compared with three in the piperacillin/tazobactam group. At 30 days, SSI had occurred in 17 patients (27.5%) in the tobramycin group and 1 patient (4.3%) in the piperacillin/tazobactam group (p = 0.033). At 60 days, SSI had occurred in three additional patients in the tobramycin group (p = 0.009). Conclusion: There was no difference in the composite AEs in the piperacillin/tazobactam compared with the tobramycin group. However, SSI within 30 and 60 days was significantly more common with tobramycin.

Gunshot Wounds to the Upper Extremity

Upper extremity gunshot wounds result in notable morbidity for the orthopaedic trauma patient. Critical neurovascular structures are particularly at risk. The fractures are often comminuted and may be associated with a variable degree of soft-tissue injury. The literature lacks consensus regarding antibiotic selection and duration, and indications for surgical débridement. Bullets and/or bullet fragments should be removed in cases of plumbism, intra-articular location, nerve impingement, location within a vessel, and location in a subcutaneous position within the hand and/or wrist. Gunshot fractures generally do not follow common fracture patterns seen in blunt injuries, and the complexity of certain gunshot fractures can often be a challenge for the treating orthopaedic surgeon. Common plate and screw constructs may not adequately stabilize these injuries, and innovative fixation techniques may be required. The treatment for bone defects varies by location and severity of injury, and typically requires staged treatment. Nerve injuries after gunshot wounds are common, but spontaneous nerve recovery is expected in most cases.

Risk Factors for Kidney Dysfunction With the Use of Gentamicin in Open Fracture Antibiotic Treatment

OBJECTIVES

To evaluate all patients who received gentamicin for open fracture treatment and determine the incidence of, and risk factors for, kidney injury in this population.

DESIGN

Retrospective, case control.

SETTING

Single institution; Level 1 trauma center.

PATIENTS/PARTICIPANTS

A retrospective chart review identified patients who received gentamicin for open fracture antibiotic treatment from January 2008 to December 2012. Overall, 371 patients met the inclusion criteria and were categorized into 2 groups using risk, injury, failure, loss of kidney function, and end-stage kidney disease criteria: normal kidney function (74.9%) versus abnormal kidney function (25.1%).

INTERVENTION

Use of gentamicin in open fracture antibiotic treatment.

MAIN OUTCOME MEASUREMENTS

Kidney function; injury and treatment characteristics (eg, mechanism of injury; Gustilo-Anderson classification; number of surgical debridements, timing of definitive wound coverage, and type of wound coverage); and patient information (eg, age, height, weight, and body mass index, tobacco use, diabetes mellitus, human immunodeficiency virus, hepatitis, and current chemotherapy treatment).

RESULTS

Those with abnormal kidney function had lower baseline creatinine (P < 0.001) and higher injury severity scores (16.5 vs. 11.8, P < 0.001) and were more likely to require intensive care unit admission (P < 0.001) than the normal group. Female sex (P = 0.015), and higher weight (P = 0.004), ICU admission (P < 0.001), and use of CT contrasted imaging (P < 0.001) were independently associated with abnormal kidney function. Abnormal kidney function incidence also sharply increased with age.

CONCLUSIONS

Females and heavier individuals are at-risk of kidney injury while receiving gentamicin. ICU admission and concurent CT contrasted imaging are strongly associated with kidney injury in patients receiving gentamicin for open fracture treatment, and gentamicin should be avoided in those >60 years of age.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Open Distal Radius Fractures: Timing and Strategies for Surgical Management

Open distal radius fractures are rare injuries with few studies to guide treatment. Degree of soft tissue injury and contamination may be a primary consideration to dictate timing and operative intervention. Antibiotics should be started as early as possible and include a first-generation cephalosporin. Surgical fixation remains a matter of surgeon preference: although studies support the use of definitive internal fixation, many surgeons address contaminated injuries with external fixation. Although postoperative outcomes are similar to closed injuries for low-grade open distal radius fractures, high-grade injuries with more complex fracture patterns carry a high risk of complications, poor outcomes, and repeat surgical procedures.

The Balance Super Learner: A robust adaptation of the Super Learner to improve estimation of the average treatment effect in the treated based on propensity score matching

Consistency of the propensity score estimators rely on correct specification of the propensity score model. The propensity score is frequently estimated using a main effect logistic regression. It has recently been shown that the use of ensemble machine learning algorithms, such as the Super Learner, could improve covariate balance and reduce bias in a meaningful manner in the case of serious model misspecification for treatment assignment. However, the loss functions normally used by the Super Learner may not be appropriate for propensity score estimation since the goal in this problem is not to optimize propensity score prediction but rather to achieve the best possible balance in the covariate distribution between treatment groups. In a simulation study, we evaluated the benefit of a modification of the Super Learner by propensity score estimation geared toward achieving covariate balance between the treated and untreated after matching on the propensity score. Our simulation study included six different scenarios characterized by various degrees of deviation from the usual main term logistic model for the true propensity score and outcome as well as the presence (or not) of instrumental variables. Our results suggest that the use of this adapted Super Learner to estimate the propensity score can further improve the robustness of propensity score matching estimators.

Renal function in patients with diabetic foot infection; does antibiotherapy affect it?

Introduction: Antibiotic treatment (antibiotherapy) of diabetic foot ulcers has been proven to have toxic effect on renal function.

Objectives: This study aimed to evaluate renal function in patients with diabetic foot infection.

Patients and Methods: This cross-sectional retrospective study was performed on 142 patients with diabetic foot ulcers hospitalized in Shahid Yahyanejad hospital of Babol during 2013. After referring to profile of the patients, they were assigned to participate in two groups: group A consisted of patients receiving antibiotics with a low risk renal toxicity and patients who received antibiotics with a higher risk of renal toxicity were placed in group B. Glomerular filtration rate (GFR) was measured and calculated based on serum concentration of creatinine and Cockcroft-Gault equation. Data was analyzed using SPSS version 20.0 with chi-square, t test and paired t tests.

Results: Group A consisted of 74 patients (52.1%) and 68 patients (47.9%) participated in group B. GFRs before and after antibiotherapy were 64.73±33.87 cc/min and 59.10±30.51 cc/min, respectively (P=0.004). In group B, GFR decreased significantly after antibiotherapy (P=0.002).

Conclusion: According to the present study, renal function decreased after antibiotherapy and in patients who received antibiotics with higher nephrotoxicity rate, the rate of this decline was higher.