Pharmacokinetic Analysis of Intravenous Push Cefepime in Burn Patients with Augmented Renal Clearance

Patients with augmented renal clearance (ARC) are a subset of critically ill patients including burn patients that exhibit increased renal elimination of medications beyond that of similarly injured patients. Currently approved maximum regimens of medications primarily eliminated by the kidney, such as cefepime (>90% unchanged in the urine), may be inadequate (eg, compromising the bactericidal activity of cefepime) in patients with ARC. Due to recent resource limitations, centers have changed infusion practices of commonly prescribed medications to intravenous push (IVP), potentially exacerbating the problem of maintaining bactericidal cefepime concentrations. The hypothesis of the study was patients with ARC are not currently achieving adequate target attainment, when receiving cefepime 2 g every 8 h IVP. Eight blood samples were collected from each patient, and concentrations measured via LC-MS/MS. WinNonlin (version 8.3) was used to estimate the pharmacokinetic parameters of cefepime and simulate plasma concentrations of cefepime in each of the ten subjects. Simulations of cefepime plasma concentrations produced by a 2 g dose given every 8 h and a 1 g dose given every 4 h were performed and the time above a MIC of 4 mg/L, 8 mg/L, and 16 mg/L compared. The 2 g every 8 h regimen remained above the breakpoints for 92%, 85%, and 71% of the dosing interval, respectively. The 1 g every 4 h regimen remained above the same breakpoints at a frequency of 100%, 99%, and 92% of the dosing interval. Giving cefepime 1 g every 4 h is a simple approach to increase the likelihood of maintaining the optimal bactericidal activity of cefepime in patients with ARC.

Reduction in Hypercalcemia Following Readjustment of Target Serum 25-Hydroxy Vitamin D Concentration during Cholecalciferol Therapy in Vitamin D-Deficient Critically Ill Patients

The intent of this study was an evaluation of our effort to reduce the incidence of hypercalcemia in critically ill vitamin D-deficient patients with multiple traumatic injuries given cholecalciferol. Vitamin D deficiency was defined as a serum 25-hydroxy vitamin D concentration (25-OH vit D) of <20 ng/mL. Adult patients (>17 years of age) were given 10,000 IU of cholecalciferol daily with an intended target 25-OH vit D of >19.9 ng/mL. These patients were compared to a historical control group that underwent therapy with a higher target of >29.9 ng/mL. Patients received cholecalciferol via the feeding tube along with enteral nutrition (EN) until the target 25-OH vit D was achieved, EN discontinued, the nutrition support service signed off the patient, or the patient was discharged from the TICU. Patients were included if two consecutive weekly 25-OH vit D were measured. One hundred and three critically ill trauma patients were retrospectively studied. Fifty were given cholecalciferol therapy with the new lower target 25-OH vit D, and 53 were from a historical cohort aiming for the higher target. Hypercalcemia (serum ionized calcium concentration > 1.32 mmol/L) was reduced from 40% (21 out of 53 patients) to 4% (2 out of 50 patients; p < 0.001). None of the hypercalcemic patients were symptomatic. Readjustment of target 25-OH vit D concentration resulted in a ten-fold decrease in the rate of hypercalcemia and improved the safety of cholecalciferol therapy for critically ill patients with traumatic injuries.

Characterization of platelet concentrations and evaluation of risk factors for thrombocytopenia following traumatic injury

Introduction

Thrombocytopenia is common in critically ill trauma patients and can lead to potentially broad differentials, including major bleeding, hemodilution, extracorporeal circuit losses, heparin-induced thrombocytopenia, and more. Understanding the normal time course of platelet decline and recovery may delineate thrombocytopenia(HIT) secondary to traumatic injury versus other inciting factors.

Methods

This retrospective study included trauma patients admitted over a 1-year period. The primary aim was characterizing the effect of trauma on platelet concentration and thrombocytopenia incidence in the first 30 days following injury. Thrombocytopenia was defined as platelet concentration <150 × 109/L. A secondary aim was evaluating significant factors contributing to thrombocytopenia.

Results

A total of 225 patients were included. Thrombocytopenia occurred in 67.3% of patients, and a platelet decline of 50% or greater occurred in 44%. Decrease in platelet concentration was significant from day 1 to day 4 (mean ± SD, 232 ± 86 vs 142 ± 76 × 109/L; p = .001). Platelets recovered to baseline on day 8 and peaked on day 16. Packed red blood cell or platelet transfusion, continuous renal replacement therapy, and acute liver injury independently predicted a ≥50% platelet decrease. HIT was not diagnosed in any patients.

Conclusion

Platelet nadir likely occurs approximately 4 days after injury and recovers relatively quickly thereafter. More studies are needed to evaluate the magnitude of effect on thrombocytopenia by factors beyond trauma.

Tigecycline to treat Stenotrophomonas maltophilia ventilator-associated pneumonia in a trauma intensive care unit as a result of a drug shortage: A case series

WHAT IS KNOWN AND OBJECTIVE

Stenotrophomonas maltophilia is an intrinsically multidrug-resistant (MDR) organism which commonly presents as a respiratory tract infection. S. maltophilia is typically treated with high-dose sulfamethoxazole/trimethoprim (SMX/TMP). However, SMX/TMP and other treatment options for S. maltophilia can be limited because of resistance, allergy, adverse events or unavailability of the drug; use of novel agents may be necessary to adequately treat this MDR infection and overcome these limitations.

CASE DESCRIPTION

This small case series describes two patients who underwent treatment with tigecycline for ventilator-associated pneumonia (VAP) caused by S. maltophilia after admission to a trauma intensive care unit. At the time of admission for the two reported patients, a national drug shortage of intravenous (IV) SMX/TMP prevented its use. Tigecycline was chosen as a novel agent to treat S. maltophilia VAP based on culture and susceptibility data, and it was used successfully. Both patients showed clinical signs of improvement with eventual cure and discharge from the hospital after treatment with tigecycline, and one patient demonstrated confirmed microbiological cure with a negative repeat bronchoscopic bronchoalveolar lavage (BAL).

WHAT IS NEW AND CONCLUSION

To our knowledge, this small case series is the first documentation of utilizing tigecycline to treat S. maltophilia VAP in the United States. Although it likely should not be considered as a first-line agent, tigecycline proved to be an effective treatment option in the two cases described in the setting of a national drug shortage of the drug of choice.

Characterization of clinical knowledge and problem-solving assessments employed in postgraduate year 1 pharmacy residency interviews

Purpose

Attainment of postgraduate year 1 (PGY1) residency positions has become increasingly competitive. Inclusion of clinical knowledge and problem-solving assessments in onsite interviews has increased in recent years. Characterization of these assessments is necessary for applicants to best prepare for interviews and for mentors to provide guidance.

Methods

An online survey was emailed to program directors of PGY1 pharmacy residency programs accredited by the American Society of Health-System Pharmacists (ASHP). Data were analyzed using descriptive statistics. Chi-square and Fisher’s exact tests were used to compare categorical data. The Mann-Whitney U test was used to analyze nonparametric continuous data.

Results

Of the 221 respondents, most identified their programs as based at community (48%) or academic (39%) medical centers. Ninety percent of programs reported inclusion of clinical knowledge and problem-solving assessments in the onsite interview process. The most common assessments included asking clinical questions (70%), development of a SOAP (subjective, objective, assessment, plan) note or care plan (42%), and formal presentations that applicants prepared prior to arrival (39%). Most programs (71%) reported incorporating multiple assessments, with 2 assessments included most commonly (43%). Clinical assessment performance accounted for 10% to 25% of the overall interview score in approximately half of programs.

Conclusion

During onsite PGY1 residency interviews, applicants must be prepared to participate in at least 1 clinical knowledge and problem-solving assessment, including answering clinical questions, developing a SOAP note or care plan, and/or delivering a presentation. Applicants should expect that these assessments will account for a substantial portion of the interview evaluation.

The effect of grit on postgraduate year-one pharmacy residents' pursuit of additional training

INTRODUCTION

Although much is known about the perceived motivating factors and barriers to individuals pursuing postgraduate year-one (PGY1) residency training, determinants for pursuit of further training after PGY1 are unclear.

METHODS

Residents at accredited programs were surveyed regarding grit, residency program and resident characteristics, and pursuit of additional post-graduate training (PGT) intentions and behaviors. Two respondent groups were developed: Pursued Additional PGT and Did Not Pursue Additional PGT. Grit-S scores were compared. A multivariable logistic regression was conducted to determine predictors of additional PGT pursuit.

RESULTS

Of 542 participating residents (response rate 14.9%), 332 (61.3%) pursued additional PGT. Residents in the Pursued Additional PGT group scored higher in overall Grit-S (median 3.875, interquartile range (IQR) 3.5-4.25 vs. median 3.75, IQR 3.375-4.125, p = 0.0006) and perseverance of effort (median 4.25, IQR 4-4.5 vs. median 4, IQR 3.75-4.5, p = 0.008) and consistency of interest (median 3.5, IQR 3-4 vs. median 3.5, IQR 2.75-3.75, p = 0.002) domains. Residents who early committed to a PGY2 had higher Grit-S scores than those who did not (median 4, IQR 3.625-4.25 vs. median 3.875, IQR 3.375-4.125, p = 0.012). Following multivariable logistic regression analysis, Grit-S score was the only variable associated with pursuit of additional PGT (odds ratio 17.8, 95% confidence interval 1.59-199.38).

CONCLUSIONS

Grit-S scores are associated with PGY1 resident decisions to pursue further PGT and to early commit to PGY2 programs.

Perceptions regarding vasopressin use and practices in septic shock, and cost containment strategies

Background

Clinician preferences and practices regarding appropriate vasopressin use in light of its increased acquisition cost secondary to rebranding has not been evaluated or described since the most recent iteration of the Surviving Sepsis Campaign Guideline was published.

Objective

To assess vasopressin cost containment initiatives and pharmacists' opinions regarding appropriate vasopressin use.

Methods

A scenario-based survey was distributed to critical care and emergency medicine pharmacists. Responses were characterized using frequency and descriptive statistics. Categorical variables between those who implemented changes (Vasopressin Cost Consideration) and those who did not (Usual Care) were compared using chi-square or Fisher's exact tests. McNemar's test was used to compare responses in clinical scenarios between Vasopressin Cost Consideration and Usual Care groups.

Results

Among 1757 pharmacists surveyed, 200 (11.3%) responded. When respondents considered vasopressin cost and evidence (vs evidence alone), fewer respondents would use vasopressin adjunctively with norepinephrine (21% vs 26.6%, P = 0.031), to raise mean arterial pressure compared with epinephrine (65.2% vs 72.3%, P = 0.012), or to reduce norepinephrine infusion rates (71.4% vs 81.4%, P < 0.001), but would use with steroids (62.4% vs 28.3%, P < 0.001). Most (72%) respondents had implemented vasopressin cost containment and/or education initiatives. The Vasopressin Cost Consideration group respondents were more likely to initiate vasopressin at 0.03 units/minute without titrating (47.9% vs 33.9%, P = 0.045).

Conclusion

Since vasopressin was generically rebranded, most institutions have implemented at least one initiative to reduce vasopressin use and/or educate clinicians about its appropriate use. When vasopressin acquisition costs were considered, pharmacists recommended its use less frequently, particularly in clinical scenarios where its use is controversial.

Critical Care PGY-2 Graduate Perceptions and Practices Regarding Residency Project Publication

Objective. To characterize the practices and perceptions of recent post-graduate year 2 (PGY2) critical care pharmacy (CCP) residents surrounding the completion and publication of their primary research project. Methods. Potential factors and perceptions influencing primary research project publication success were identified and incorporated in a validated electronic survey distributed to 2011 and 2012 PGY2 CCP residency program graduates. Results. Among the 94/124 (76%) respondents, 26% had published their research project (67% were first authors; 50% were successful on first submission), while 36% still planned to pursue publication, and 38% had no plans for their manuscript. Factors more commonly reported by publishing (vs. non-publishing) PGY2 graduates included: publication of their PGY1 research project, any publication during the PGY2 year, and national presentation of the PGY2 research project. Perceptions associated with research project publication success were a higher degree of self-motivation to publish, post-PGY2 mentor support, project's publication deemed important to post-PGY2 employer, adequate training for manuscript submission, and adequate time during residency for manuscript completion. Two factors, ≥1 publication during PGY2 [odds ratio (OR)=3.7; 95% confidence interval (CI) 1.3, 10.2] and research project presentation at a national conference (OR=4.5; 95% CI 1.2, 16.9); and two perceptions, self-motivation to publish (OR=8.1; 95% CI 1.7, 37.7) and post-PGY2 mentor support (OR=3.3; 95% CI 1.1, 9.8) were independently associated with publication success. Conclusion. Only one-quarter of PGY2 CCP residents published their primary research project. PGY2 programs should consider those factors associated with research project publication success when formulating strategies to increase resident publication rates.

Association between postgraduate year 2 residency program characteristics and primary project publication

PURPOSE

The association among residency program and research mentor characteristics, program director perceptions, and the publication of the primary research project for postgraduate year 2 (PGY2) graduates was assessed.

METHODS

Using a validated electronic survey, residency program directors (RPDs) of critical care PGY2 graduates were asked about primary research project publication success, program and research project mentor characteristics, and RPDs' perceptions surrounding project completion.

RESULTS

All 55 RPDs surveyed responded; 44 (79%) reported being a research project mentor. PGY2 research project publications in 2011 and 2012 totaled 26 (37%) and 27 (35%), respectively. A significant relationship existed between research project publication and the number of residents in the program (p < 0.01); the perception among the RPDs that research project publication is important to their employer (p < 0.01); and the research mentor's funding source (p = 0.04), employer (p < 0.01), number of prior publications (p = 0.01), and research training (p < 0.01). Variables independently associated with the publication of 2 or more research projects versus no publications included the number of graduates in the PGY2 program (odds ratio [OR], 5.6; p < 0.01), the RPD's perception that the employer valued research project publication (OR, 10.2; p < 0.01), and the number of prior publications by the least-experienced research mentor (OR, 23.5; p = 0.01). The publication of 1 research project versus no research projects was also independently associated with the RPD's perception that the employer valued research project publication (OR, 5.1; p = 0.04).

CONCLUSION

A survey of RPDs of critical care PGY2 residents found that the number of PGY2 residents, the number of publications by the least experienced research mentor, and the perception that publishing the residents' research projects is important to the employer were independently associated with publication rates of residency research projects.

Use of Aerosolized Antibiotics in Gram-Negative Ventilator-Associated Pneumonia in Trauma Patients

Ventilator-associated pneumonia (VAP) is associated with significant morbidity (ventilator days, ICU days, and cost) and mortality increase in trauma patients. Multidrug-resistant strains of causative VAP pathogens are becoming increasingly common. Aerosolized antibiotics achieve high alveolar concentrations and provide valuable adjuncts in the treatment of VAP. This study examined the impact of aerosolized antibiotics in the treatment of VAP in trauma patients. Patients with either Acinetobacter baumannii or Pseudomonas aeruginosa VAP over 10 years treated with aerosolized antibiotics (cases) were stratified by age, severity of shock, and injury severity. A frequency-matched (by causative pathogen) control group treated without aerosolized antibiotics was used for comparison. Multivariable logistic regression was used to identify predictors for the use of aerosolized antibiotics. One hundred twenty VAP episodes were identified in 100 patients. Microbiologic resolution was achieved in all patients treated with aerosolized antibiotics. There was no difference in mortality (14.5% vs 15.7%, P = 0.87) and no antibiotic-related complications in either group. Multivariable logistic regression identified VAP persistence and relapse as independent predictors for the use of aerosolized antibiotics. Combined with systemic therapy, aerosolized antibiotics broaden the spectrum of therapy. They are valuable adjuncts with minimal risk of antibiotic resistance and/or systemic complications.

Use of Aerosolized Antibiotics in Gram-Negative Ventilator-Associated Pneumonia in Trauma Patients

Ventilator-associated pneumonia (VAP) is associated with significant morbidity (ventilator days, ICU days, and cost) and mortality increase in trauma patients. Multidrug-resistant strains of causative VAP pathogens are becoming increasingly common. Aerosolized antibiotics achieve high alveolar concentrations and provide valuable adjuncts in the treatment of VAP. This study examined the impact of aerosolized antibiotics in the treatment of VAP in trauma patients. Patients with either Acinetobacter baumannii or Pseudomonas aeruginosa VAP over 10 years treated with aerosolized antibiotics (cases) were stratified by age, severity of shock, and injury severity. A frequency-matched (by causative pathogen) control group treated without aerosolized antibiotics was used for comparison. Multivariable logistic regression was used to identify predictors for the use of aerosolized antibiotics. One hundred twenty VAP episodes were identified in 100 patients. Microbiologic resolution was achieved in all patients treated with aerosolized antibiotics. There was no difference in mortality (14.5% vs 15.7%, P = 0.87) and no antibiotic-related complications in either group. Multivariable logistic regression identified VAP persistence and relapse as independent predictors for the use of aerosolized antibiotics. Combined with systemic therapy, aerosolized antibiotics broaden the spectrum of therapy. They are valuable adjuncts with minimal risk of antibiotic resistance and/or systemic complications.

Treatment of Achromobacter Ventilator-Associated Pneumonia in Critically Ill Trauma Patients

BACKGROUND

Achromobacter sp are nonfermenting Gram-negative bacilli (NFGNB) that rarely cause severe infections, including ventilator-associated pneumonia (VAP). Data on the treatment of Achromobacter pneumonia are very limited, and the organism has been associated with a high mortality rate. Thus, more data are needed on treating this organism.

OBJECTIVE

To evaluate the treatment of Achromobacter VAP in critically ill trauma patients.

METHODS

This retrospective, observational study evaluated critically ill trauma patients who developed Achromobacter VAP. A previously published pathway for the diagnosis and management of VAP was used according to routine patient care. This included the use of quantitative bronchoscopic bronchoalveolar lavage cultures to definitively diagnose VAP.

RESULTS

A total of 37 episodes of Achromobacter VAP occurred in 34 trauma intensive care unit patients over a 15-year period. The most commonly used definitive antibiotics were imipenem/cilastatin, cefepime, or trimethoprim/sulfamethoxazole. The primary outcome of clinical success was achieved in 32 of 37 episodes (87%). This is similar to previous studies of other NFGNB VAP (eg, Pseudomonas, Acinetobacter) from the study center. Microbiological success was seen in 21 of 28 episodes (75%), and VAP-related mortality was 9% (3 of 34 patients).

CONCLUSIONS

Achromobacter is a rare but potentially serious cause of VAP in critically ill patients. In this study, there was an acceptable success rate compared with other causes of NFGNB VAP in this patient population.

An Update on Aerosolized Antibiotics for Treating Hospital-Acquired and Ventilator-Associated Pneumonia in Adults

OBJECTIVE

A significant percentage of patients with hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) have poor outcomes with intravenous antibiotics. It is not clear if adding aerosolized antibiotics improves treatment. This review is an update on using aerosolized antibiotics for treating HAP/VAP in adults.

DATA SOURCES

PubMed search using the terms "aerosolized antibiotics pneumonia," "nebulized antibiotics pneumonia," and "inhaled antibiotics pneumonia." Reference lists from identified articles were also searched.

STUDY SELECTION AND DATA EXTRACTION

Clinical studies of aerosolized antibiotics for treating HAP/VAP in adults from July 2010 to March 2017. This article updates a previous review on this topic written in mid-2010.

DATA SYNTHESIS

The size and quality of studies have improved dramatically in the recent time period compared to previous studies. However, there still are not large randomized controlled trials available. Colistin and aminoglycosides were the most commonly studied agents, and the most common pathogens were Pseudomonas and Acinetobacter. The clinical efficacy of adding aerosolized antibiotics was mixed. Approximately half of the studies showed better outcomes, and none showed worse outcomes. Aerosolized antibiotics appear to be relatively safe, though pulmonary adverse events can occur. Attention to proper administration technique in mechanically ventilated patients is required, including the use of vibrating plate nebulizers.

CONCLUSIONS

Adding aerosolized antibiotics to intravenous antibiotics may improve the outcomes of adult patients with HAP/VAP in some settings. It seems reasonable to add aerosolized antibiotics in patients with multidrug-resistant organisms or who appear to be failing therapy. Clinicians should pay attention to potential adverse events and proper administration technique.

Perceived Motivating Factors and Barriers for the Completion of Postgraduate Training Among American Pharmacy Students Prior to Beginning Advanced Pharmacy Practice Experiences

Objective. To examine perceived motivating factors and barriers (MFB) to postgraduate training (PGT) pursuit among pharmacy students. Methods. Third-year pharmacy students at 13 schools of pharmacy provided demographics and their plan and perceived MFBs for pursuing PGT. Responses were characterized using descriptive statistics. Kruskal-Wallis equality-of-proportions rank tests determined if differences in perceived MFBs existed between students based on plan to pursue PGT. Results. Among 1218 (69.5%) respondents, 37.1% planned to pursue PGT (32.9% did not, 30% were undecided). Students introduced to PGT prior to beginning pharmacy school more frequently planned to pursue PGT. More students who planned to pursue PGT had hospital work experience. The primary PGT rationale was, "I desire to gain more knowledge and experience." Student debt was the most commonly cited barrier. Conclusion. Introducing pharmacy students early to PGT options and establishing work experiences in the hospital setting may increase students' desire to pursue PGT.

Pharmacokinetics of Imipenem/Cilastatin Burn Intensive Care Unit Patients Undergoing High-Dose Continuous Venovenous Hemofiltration

STUDY OBJECTIVE

High-dose continuous venovenous hemofiltration (CVVH) is a continuous renal replacement therapy (CRRT) used frequently in patients with burns. However, antibiotic dosing is based on inference from studies assessing substantially different methods of CRRT. To address this knowledge gap for imipenem/cilastatin (I/C), we evaluated the systemic and extracorporeal clearances (CLs) of I/C in patients with burns undergoing high-dose CVVH.

DESIGN

Prospective clinical pharmacokinetic study.

PATIENTS

Ten adult patients with burns receiving I/C for a documented infection and requiring high-dose CVVH were studied.

METHODS

Blood and effluent samples for analysis of I/C concentrations were collected for up to 6 hours after the I/C infusion for calculation of I/C total CL (CL_Total ), CL by CVVH (CL_HF ), half-life during CVVH, volume of distribution at steady state (Vd_ss ), and the percentage of drug eliminated by CVVH.

RESULTS

In this patient sample, the mean age was 50 ± 17 years, total body surface area burns was 23 ± 27%, and 80% were male. Nine patients were treated with high-dose CVVH for acute kidney injury and one patient for sepsis. The mean delivered CVVH dose was 52 ± 14 ml/kg/hour (range 32-74 ml/kg/hr). The imipenem CL_HF was 3.27 ± 0.48 L/hour, which accounted for 23 ± 4% of the CL_Total (14.74 ± 4.75 L/hr). Cilastatin CL_HF was 1.98 ± 0.56 L/hour, which accounted for 45 ± 19% of the CL_Total (5.16 + 2.44 L/hr). The imipenem and cilastatin half-lives were 1.77 ± 0.38 hours and 4.21 ± 2.31 hours, respectively. Imipenem and cilastatin Vd_ss were 35.1 ± 10.3 and 32.8 ± 13.8 L, respectively.

CONCLUSION

Efficient removal of I/C by high-dose CVVH, a high overall clearance, and a high volume of distribution in burn intensive care unit patients undergoing this CRRT method warrant aggressive dosing to treat serious infections effectively depending on the infection site and/or pathogen.

Vitamin D deficiency in critically ill patients with traumatic injuries

Background

Vitamin D depletion has been associated with increased rate of infections, lengthened hospital stay, and worsened mortality for critically ill patients. The purpose of this study was to evaluate the prevalence and variables associated with vitamin D deficiency in critically ill patients with severe traumatic injuries.

Methods

Critically ill adult patients admitted to the trauma intensive care unit (ICU) between June 2013 and June 2014, referred to the nutrition support service for enteral or parenteral nutrition, and had a serum 25-hydroxyvitamin D (25-OH vitamin D) concentration determination were retrospectively evaluated. Patients were stratified as vitamin D sufficient, insufficient, deficient, or severely deficient based on a 25-OH vitamin D concentration of 30–80, 20–29.9, 13.1–19.9, and ≤13 ng/mL, respectively.

Results

One hundred and twenty-one patients out of 158 (76 %) patients were vitamin D deficient or severely deficient. Thirty-one patients (20 %) were insufficient and 6 (4 %) had a normal 25-OH vitamin D concentration. 25-OH vitamin D was determined 7.5 ± 5.1 days after ICU admission. African-Americans had a greater proportion of patients with deficiency or severe deficiency compared to other races (91 versus 64 %, P = 0.02). Penetrating gunshot or knife stab injury, African-American race, and obesity (elevated body mass index) were significantly associated with vitamin D deficiency or severe deficiency: OR 9.23 (1.13, 75.40), 4.0 (1.4, 11.58), and 1.12 (1.03, 1.23), P < 0.05, respectively.

Conclusions

The majority of critically ill patients with traumatic injuries exhibit vitamin D deficiency or severe deficiency. Penetrating injuries, African-American race, and obesity are significant risk factors for deficiency. Severity of injury, extent of inflammation (elevated C-reactive protein concentration), or hospital admission during the winter season did not significantly influence the prevalence of vitamin D deficiency.

Dose-response effect of ergocalciferol therapy on serum 25-hydroxyvitamin D concentration during critical illness

OBJECTIVE

The aim of this study was to evaluate the dose-response relationship between ergocalciferol therapy and serum 25-hydroxyvitamin D concentrations in enterally fed, critically ill patients with traumatic injuries.

METHODS

A retrospective cohort of critically ill patients with traumatic injuries and vitamin D deficiency (25-OH vitamin D <50 nmol/L) were given either 50 000 IU of liquid ergocalciferol weekly, twice weekly, or three times weekly while in the intensive care unit (ICU). Serum 25-OH vitamin D and ionized calcium concentrations were monitored weekly. Ergocalciferol therapy was stopped when the serum 25-OH vitamin D was >75 nmol/L, if the patient experienced hypercalcemia (ionized calcium >1.34 mmol/L), when the patient was discharged from the ICU, or if enteral nutrition was discontinued.

RESULTS

Sixty-five patients (16, 18, and 31 per dosage group) were examined. One (6%), two (11%), and eight (26%) patients achieved normal 25-OH vitamin D concentrations after 2 to 4 wk of ergocalciferol therapy for each dosage group, respectively (P < 0.001). Serum 25-OH vitamin D concentrations improved from 36 ± 6, 40 ± 7, and 37 ± 6 nmol/L to 50 ± 15, 54 ± 21, and 62 ± 17 nmol/L, respectively, after 2 wk of ergocalciferol therapy (P < 0.001) Two (13%), one (6%), and seven (23%) patients developed hypercalcemia for each dosage group, respectively (P = NS).

CONCLUSIONS

Ergocalciferol therapy improved baseline serum 25-OH vitamin D concentrations but was inadequate for consistently achieving normal serum concentrations of 25-OH vitamin D during critical illness. The trend in increasing appearance of mild hypercalcemia for the highest dosage group is concerning.

Adjunctive intraventricular antibiotic therapy for bacterial central nervous system infections in critically ill patients with traumatic brain injury

BACKGROUND

Limited data exist on the role of adjunctive intraventricular (IVT) antibiotics for the treatment of central nervous system (CNS) infections in traumatic brain injury (TBI) patients.

OBJECTIVE

To evaluate differences in CNS infection cure rates for TBI patients who received adjunctive IVT antibiotics compared with intravenous (IV) antibiotics alone.

METHODS

We retrospectively identified patients with TBI and bacterial CNS infections admitted to the trauma intensive care unit (ICU) from 1997 to 2013. Study patients received IV and IVT antibiotics, and control patients received IV antibiotics alone. Clinical and microbiological cure rates were determined from patient records, in addition to ICU and hospital lengths of stay (LOSs), ventilator days, and hospital mortality.

RESULTS

A total of 83 patients were enrolled (32 study and 51 control). The duration of IV antibiotics was similar in both groups (10 vs 12 days, P = 0.14), and the study group received IVT antibiotics for a median of 9 days. Microbiological cure rates were 84% and 82% in study and control groups, respectively (P = 0.95). Clinical cure rates were similar at all time points. No significant differences were seen in days of mechanical ventilation, ICU or hospital LOS, or hospital mortality. When only patients with external ventricular drains were compared, cure rates remained similar between groups.

CONCLUSIONS

TBI patients with CNS infections had similar microbiological and clinical cure rates whether they were treated with adjunctive IVT antibiotics or IV antibiotics alone. Shorter than recommended durations of antibiotic therapy still resulted in acceptable cure rates and similar clinically relevant outcomes.

Impact of pathogen-directed antimicrobial therapy for ventilator-associated pneumonia in trauma patients on charges and recurrence

BACKGROUND

Ventilator-associated pneumonia (VAP) represents one of the driving forces behind antibiotic use in the ICU. In a previous study, we established a defined algorithm for treatment of hospital-acquired VAP dictated by the causative pathogen. The purpose of the current study was to evaluate the impact of this algorithm for hospital-acquired VAP on recurrence and charges in trauma patients.

STUDY DESIGN

Patients with VAP secondary to MRSA, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, or Enterobacteriaceae during 5 years subsequent to the previous study were evaluated. All VAP were diagnosed using quantitative cultures of the bronchoalveolar lavage effluent. Duration of antimicrobial therapy was dictated by the causative pathogen. If microbiologic resolution, defined as <10(3) colony-forming units/mL, was achieved, therapy was stopped by day 10. The remainder received 14 days of therapy. Recurrence was defined as >10(5) colony-forming units/mL on subsequent bronchoalveolar lavage performed within 2 weeks after completion of appropriate therapy.

RESULTS

Five hundred and twenty-nine VAP episodes were identified in 381 patients. Overall recurrence was unchanged compared with the previous study (1.5% vs 2%; p = 0.3). There was a decrease in the number of bronchoalveolar lavages performed per patient compared with the previous study (1.6 vs 2.3; p = 0.24) and a reduction of 4.8 antibiotic days per VAP episode compared with the previous study. Both changes resulted in a cumulative reduction of $3,535.04 per patient, for a savings of $1.35 million during the study period.

CONCLUSIONS

Hospital-acquired VAP can be managed effectively by a defined course of therapy dictated by the causative pathogen. Adherence to an established algorithm simplified the management of VAP and contributed to a cumulative reduction in patient charges without impacting recurrence.

Treatment of Rhizobium radiobacter bacteremia in a critically ill trauma patient

OBJECTIVE

To report the first case of Rhizobium radiobacter bacteremia in a critically ill trauma patient.

CASE SUMMARY

A 36-year-old female trauma patient hospitalized at The Regional Medical Center at Memphis developed bacteremia due to Rhizobium radiobacter on hospital day 9. The central line catheter tip culture from the same hospital day was negative. No source for the R radiobacter bacteremia was identified. Empirical and definitive antibiotic therapy consisted of cefepime 2 g intravenously every 8 hours for at total of 8 days. On completion of antibiotics, the patient demonstrated clinical resolution by immediate defervescence and gradual normalization of her white blood cell count. She demonstrated microbiologic success of therapy with negative blood cultures on hospital days 22, 34, 45, and 61. She was discharged on hospital day 80.

DISCUSSION

Rhizobium species are common soil and plant pathogens that rarely cause infections in humans. Previous reports of Rhizobium infections have been in immunocompromised patients; generally those with cancer or HIV infection. Intravenous catheters have commonly been cited as the source of infection. The trauma patient in this case constitutes a unique presentation of R radiobacter bacteremia when compared with other case reports. Her indwelling catheter was not the source of her infection, and her only identifiable risk factor for R radiobacter infection was hospitalization. However, she did possess potential reasons for development of an infection with an unusual organism such as R radiobacter. Potential immune modulating therapies included blood transfusions, opioid analgesics, benzodiazepines, general anesthetics, and surgical procedures. Finally, trauma itself has been associated with some degree of immunosuppression. All these issues may have placed the patient in this case at risk of an opportunistic infection like R radiobacter.

CONCLUSION

Based on this case, R radiobacter may be considered a potential pathogen causing bacteremia in critically ill trauma patients.

Treatment of Chryseobacterium indologenes ventilator-associated pneumonia in a critically ill trauma patient

OBJECTIVE

To report a case of Chryseobacterium indologenes ventilator-associated pneumonia (VAP) in a critically ill trauma patient.

CASE SUMMARY

This report describes a 66-year-old critically ill trauma patient who developed VAP, which was caused by C indologenes. The patient was injured in a riding lawn mower accident that trapped him underwater in a pond. The patient required surgery for intra-abdominal injuries and was mechanically ventilated in the trauma intensive care unit. On hospital day 5, the patient developed signs and symptoms of VAP. A diagnosis of C indologenes VAP was confirmed based on a quantitative culture from a bronchoscopic bronchoalveolar lavage. The patient's infection was successfully treated with moxifloxacin for 2 days followed by cefepime for 7 days.

DISCUSSION

Formally known as Flavobacterium indologenes, C indologenes is a Gram-negative bacillus normally found in plants, soil, foodstuffs, and fresh and marine water sources. Recently, worldwide reports of C indologenes infections in humans have been increasing, though reports from the United States are still rare. Bacteremia and pneumonia are the most commonly reported infections, and most patients are immunocompromised. The current case differs from most previous reports because this patient was in the United States and did not have any traditional immunocompromised states (eg, transplant, cancer, HIV/AIDS, or corticosteroid use).

CONCLUSION

This case report demonstrates that C indologenes can cause VAP in a trauma ICU patient.

Effectiveness of pseudoephedrine as adjunctive therapy for neurogenic shock after acute spinal cord injury: a case series

STUDY OBJECTIVE

To evaluate the effectiveness of pseudoephedrine as adjunctive therapy for neurogenic shock in patients with acute spinal cord injury (SCI).

DESIGN

Case series.

SETTING

Academic medical center.

PATIENTS

Thirty-eight patients admitted to the trauma intensive care unit between September 2005 and October 2012 with an acute SCI and who received more than 1 day of pseudoephedrine for one or more of the following: treatment of bradycardia (heart rate ≤ 50 beats/min), treatment of hypotension (systolic blood pressure < 90 mm Hg), or were receiving intravenous vasopressor support.

MEASUREMENTS AND MAIN RESULTS

The effect of adjunctive pseudoephedrine (PSE) was categorized as a success if vasopressors were discontinued after the initiation of PSE or improvement in the number of episodes of bradycardia was noted after the initiation of PSE as evidenced by decreased use of atropine. The effect of pseudoephedrine was categorized as a failure if it did not meet one of the criteria for success. The effect of pseudoephedrine was categorized as inconclusive if there were confounding factors such as vasopressors being restarted for another indication after initial discontinuation. Pseudoephedrine was successful in 31/38 (82%) patients, failed in 2/38 (5%) patients, and had inconclusive results in 5/38 (13%) patients. The mean ± SD time to successful weaning of intravenous vasopressors was 7 ± 7 days. Daily maximum pseudoephedrine doses ranged from 60-720 mg. Mean ± SD duration of pseudoephedrine therapy was 32 ± 23 days (range 2-135 days), with 64.5% of surviving patients discharged while receiving pseudoephedrine.

CONCLUSION

These data suggest that pseudoephedrine is an effective adjunctive therapy in facilitating the discontinuation of intravenous vasopressors and/or atropine in patients with acute SCI with neurogenic shock, although patients will typically require long durations of therapy.

Pooling/bootstrap-based GWAS (pbGWAS) identifies new loci modifying the age of onset in PSEN1 p.Glu280Ala Alzheimer's disease

The literature on GWAS (genome-wide association studies) data suggests that very large sample sizes (for example, 50,000 cases and 50,000 controls) may be required to detect significant associations of genomic regions for complex disorders such as Alzheimer's disease (AD). Because of the challenges of obtaining such large cohorts, we describe here a novel sequential strategy that combines pooling of DNA and bootstrapping (pbGWAS) in order to significantly increase the statistical power and exponentially reduce expenses. We applied this method to a very homogeneous sample of patients belonging to a unique and clinically well-characterized multigenerational pedigree with one of the most severe forms of early onset AD, carrying the PSEN1 p.Glu280Ala mutation (often referred to as E280A mutation), which originated as a consequence of a founder effect. In this cohort, we identified novel loci genome-wide significantly associated as modifiers of the age of onset of AD (CD44, rs187116, P=1.29 × 10⁻¹²; NPHP1, rs10173717, P=1.74 × 10⁻¹²; CADPS2, rs3757536, P=1.54 × 10⁻¹⁰; GREM2, rs12129547, P=1.69 × 10⁻¹³, among others) as well as other loci known to be associated with AD. Regions identified by pbGWAS were confirmed by subsequent individual genotyping. The pbGWAS methodology and the genes it targeted could provide important insights in determining the genetic causes of AD and other complex conditions.

The relationship between serum sodium and intracranial pressure when using hypertonic saline to target mild hypernatremia in patients with head trauma

INTRODUCTION

Limited data suggest mild hypernatremia may be related to lower intracranial pressure (ICP) in patients with traumatic brain injury (TBI). The practice at the study center has been to use hypertonic saline (HTS) to generate a targeted serum sodium of 145 to 155 mEq/l in patients with TBI. The purpose of this study was to determine the relationship between serum sodium values and ICP, and to evaluate the acute effect of HTS on ICP.

METHODS

A retrospective review of patients who were admitted to the trauma ICU for TBI, had an ICP monitor placed, and received at least one dose of HTS between January 2006 and March 2011 was performed. Data were collected for up to 120 hours after ICP monitor placement. The primary outcome was the relationship between serum sodium and maximum ICP. Secondary outcomes were the relationship between serum sodium and the mean number of daily interventions for ICP control, and the acute effect of HTS on ICP during the 6 hours after each dose. Linear regression was used to analyze the primary outcome. Analysis of variance on ranks and repeated measures analysis of variance were used to evaluate the number of interventions and the acute effect of HTS on ICP, respectively.

RESULTS

Eighty-one patients were enrolled with mean ± standard deviation age of 36 ± 15 years and median Glasgow Coma Scale score of 7 (interquartile range, 4 to 7). A total of 1,230 serum sodium values (range, 118 to 174 mEq/l) and 7,483 ICP values (range, 0 to 159 mmHg) were collected. There was no correlation between serum sodium and maximum ICP (R(2) = 0.0052). The overall mean ± standard deviation number of interventions for elevated ICP per day was 4.2 ± 2.9, 2.9 ± 2.0, and 2.6 ± 2.3 for patients with a mean serum sodium of < 145, 145 to 155, and > 155 mEq/l, respectively (P < 0.001). Regarding the acute effect of HTS on ICP, there was no statistical difference in mean ICP compared with baseline during hours 1 through 6 following HTS doses (baseline, 13.7 ± 8.4 mmHg; hour 1, 13.6 ± 8.3 mmHg; hour 2, 13.5 ± 8.8 mmHg; hour 3, 13.3 ± 8.7 mmHg; hour 4, 13.4 ± 8.7 mmHg; hour 5, 13.4 ± 8.3 mmHg; hour 6, 13.5 ± 8.3 mmHg; P = 0.84).

CONCLUSIONS

Serum sodium concentrations did not correlate with ICP values. These results warrant further evaluation and possible reassessment of sodium goals for ICP management in patients with TBI.

Clinical and microbiologic outcomes in trauma patients treated for Stenotrophomonas maltophilia ventilator-associated pneumonia

STUDY OBJECTIVES

To determine clinical and microbiologic plus clinical success rates in critically ill trauma patients who received treatment for Stenotrophomonas maltophilia ventilator-associated pneumonia (VAP).

DESIGN

Retrospective medical record review.

SETTING

Level I trauma intensive care unit of a large academic medical center.

PATIENTS

A total of 101 patients who developed S. maltophilia VAP between January 1997 and December 2007.

MEASUREMENTS AND MAIN RESULTS

Patients' baseline demographic and clinical characteristics, as well as characteristics of their VAP, were documented. The primary study outcome was the rate of clinical success in patients with S. maltophilia VAP; a secondary outcome was microbiologic plus clinical success rate in these patients. Standard definitions were employed to determine these outcomes related to VAP treatment. The study population had higher injury severity scores and a higher rate of traumatic brain injury than is typically observed in the study's intensive care unit. The median time to diagnosis of S. maltophilia VAP was 15 days (interquartile range 11-24 days). Stenotrophomonas maltophilia was the sole organism isolated in 34% of patients; the other patients had polymicrobial VAP. Despite inadequate empiric antibiotic therapy being administered to 97% of the patients, the overall clinical success rate was 87%. The microbiologic plus clinical success rate was 82%. The most common treatments for S. maltophilia VAP were trimethoprim-sulfamethoxazole (77 patients received monotherapy, 9 received combination therapy) and ciprofloxacin (6 patients received monotherapy, 8 received combination therapy); all-cause and VAP-related mortality rates were 13% and 7%, respectively.

CONCLUSION

Critically ill trauma patients with S. maltophilia VAP responded well to therapy despite high rates of inadequate empiric antibiotic administration. Trimethoprim-sulfamethoxazole was the most common therapy, but clinical success rates did not differ significantly based on antibiotic selection. This study adds significantly to the available S. maltophilia VAP outcomes data.

Treatment of recurrent Stenotrophomonas maltophilia ventilator-associated pneumonia with doxycycline and aerosolized colistin

OBJECTIVE

To report a case of recurrent Stenotrophomonas maltophilia ventilator-associated pneumonia (VAP) that was successfully treated with doxycycline and aerosolized colistin.

CASE SUMMARY

A 28-year-old male was admitted with a severe head injury and required mechanical ventilation. The patient developed S. maltophilia VAP on hospital day 17, which was cured after 7 days of treatment with high-dose intravenous trimethoprim/sulfamethoxazole (TMP/SMX). However, on day 34, the patient developed recurrent S. maltophilia VAP that did not respond clinically or demonstrate eradication on follow-up culture after 10 days of TMP/SMX. At that time, TMP/SMX was discontinued and treatment was initiated with intravenous doxycycline and aerosolized colistin. The VAP episode was cured after 14 days of treatment with doxycycline/aerosolized colistin.

DISCUSSION

S. maltophilia is an emerging cause of VAP in some centers. This organism is associated with high mortality rates and has few treatment options because it is intrinsically resistant to most drug classes. Recent data suggest that doxycycline and aerosolized colistin each are effective in treatment of other multidrug-resistant organisms, such as Pseudomonas aeruginosa and Acinetobacter baumannii. However, this is the first report describing the use of this antibiotic regimen for S. maltophilia. High-dose TMP/SMX is considered to be the drug of choice primarily based on excellent in vitro activity. Few data exist on how to treat patients who fail therapy with TMP/SMX or cannot receive that drug because of resistance, allergy, or adverse events. Thus, it is important to report alternative methods for treating this infection.

CONCLUSIONS

The positive clinical response to doxycycline and aerosolized colistin seen in the patient described here suggests that this combination may be an alternative treatment in patients who fail initial treatment or cannot receive standard therapies.

Adjunctive aerosolized antibiotics for treatment of ventilator-associated pneumonia

STUDY OBJECTIVE

To determine clinical and microbiologic success in patients receiving adjunctive aerosolized antibiotics for the treatment of ventilator-associated pneumonia (VAP).

DESIGN

Retrospective medical record review.

SETTING

Level I trauma intensive care unit of a large academic medical center.

PATIENTS

Forty-nine patients (mean +/- SD age 42 +/- 19 yrs) who received aerosolized antibiotics for the treatment of a total of 60 episodes of VAP caused by Pseudomonas aeruginosa and/or Acinetobacter baumannii between January 2001 and July 2007.

MEASUREMENTS AND MAIN RESULTS

Patients were identified by using an existing database of patients with documented VAP at the study center. To receive a diagnosis of VAP, patients had to have bacterial growth of 10(5) or more colony-forming units/ml from a bronchoscopic bronchoalveolar lavage and new or changing infiltrate on chest radiograph, plus at least two of the following: abnormal body temperature (> 38 degrees C or < 36 degrees C), abnormal white blood cell count (> 10 or < 4 x 10(3)/mm(3), or > 10% immature bands), or macroscopically purulent sputum. By reviewing patient data, we evaluated clinical and microbiologic success using standard definitions. The median (interquartile range) Injury Severity Score and admission Acute Physiology and Chronic Health Evaluation II score were 40 (29-45) and 17 (9-21), respectively. Pseudomonas aeruginosa, A. baumannii, or both were isolated in 45, 14, and 1 episode(s), respectively. Eighteen VAP episodes included additional bacteria. Aerosolized tobramycin, amikacin, and colistimethate were used in 44, 9, and 9 episodes, respectively. Systemic antibiotics were used in 59 (98%) of the 60 episodes. Clinical success was achieved in 36 (73%) of the 49 first episodes of VAP, 8 (73%) of 11 subsequent episodes, 17 (85%) of 20 episodes that were failing intravenous monotherapy, and 30 (79%) of 38 episodes with multidrug-resistant P. aeruginosa or A. baumannii. Microbiologic success was achieved in 29 (71%) of 41 evaluable episodes. Six patients died from VAP.

CONCLUSION

Treatment with adjunctive aerosolized antibiotics was associated with a good response rate in critically ill trauma patients with VAP due to nonfermenting gram-negative bacilli. It is noteworthy that episodes of VAP that followed intravenous therapy failure and/or that were due to multidrug-resistant organisms responded well.

Evaluation of glycemic control following discontinuation of an intensive insulin protocol

BACKGROUND

Intensive insulin protocols (IIPs) have been demonstrated to reduce morbidity and mortality in critically ill patients. Currently, there are no published studies evaluating glycemic control after discontinuation of an IIP.

OBJECTIVE

The purpose of this study was to compare blood glucose (BG) control during an IIP and for 5 days following its discontinuation (follow-up period).

METHODS

The study was a retrospective review of intensive care unit patients who received an IIP for >or=24 hours. Data were collected during the last 12 hours of the IIP and subsequent follow-up period.

RESULTS

For all 65 included patients, the mean +/- standard deviation for BG on the IIP was 123 +/- 26 mg/dL versus 168 +/- 50 mg/dL following discontinuation of the IIP (P < 0.001). The median (interquartile range) insulin that was administered decreased from 40 (22-65) units on the IIP to 8 (0-18) units after the IIP was stopped (P < 0.001). The mean daily BG during the follow-up period was significantly higher than that during the IIP (P < 0.001). Additionally, an insulin requirement of >20 units during the last 12 hours of the IIP was identified as a risk factor for poor glycemic control during the follow-up period (odds ratio: 4.62; 95% confidence interval: 1.17-18.17).

CONCLUSIONS

This study demonstrates a significant increase in BG following discontinuation of an IIP. Higher insulin requirements during the last 12 hours of an IIP were identified as an independent risk factor for poor glycemic control following the IIP. A standardized insulin transition protocol may help better control BG after discontinuation of an IIP.

Reduction in Inadequate Empiric Antibiotic Therapy for Ventilator-Associated Pneumonia: Impact of a Unit-Specific Treatment Pathway

Empiric antibiotic therapy is routinely initiated for patients with presumed ventilator-associated pneumonia (VAP). Reported mortality rates for inadequate empiric antibiotic therapy (IEAT) for VAP range from 45 to 91 per cent. The purpose of this study was to determine the effect of a unit-specific pathway for the empiric management of VAP on reducing IEAT episodes and improving outcomes in trauma patients. Patients admitted with VAP over 36-months were identified and stratified by gender, age, severity of shock, and injury severity. Outcomes included number of IEAT episodes, ventilator days, intensive care unit days, hospital days, and mortality. Three hundred and ninety-three patients with 668 VAP episodes were identified. There were 144 (22%) IEAT episodes: significantly reduced compared with our previous study (39%) ( P < 0.001). Patients were classified by number of IEAT episodes: 0 (n = 271), 1 (n = 98) and ≥ 2 (n = 24). Mortality was 12 per cent, 13 per cent, and 38 per cent ( P < 0.001), respectively. Multivariable logistic regression identified multiple IEAT episodes as an independent predictor of mortality (odds ratio = 4.7; 95% confidence interval: 1.684–13.162). Multiple IEAT episodes were also associated with prolonged mechanical ventilation and intensive care unit stay ( P < 0.001). Trauma patients with multiple IEAT episodes for VAP have increased morbidity and mortality. Adherence to a unit-specific pathway for the empiric management of VAP reduces multiple IEAT episodes. By limiting IEAT episodes, resource utilization and hospital mortality are significantly decreased.

Reduction in inadequate empiric antibiotic therapy for ventilator-associated pneumonia: impact of a unit-specific treatment pathway

Empiric antibiotic therapy is routinely initiated for patients with presumed ventilator-associated pneumonia (VAP). Reported mortality rates for inadequate empiric antibiotic therapy (IEAT) for VAP range from 45 to 91 per cent. The purpose of this study was to determine the effect of a unit-specific pathway for the empiric management of VAP on reducing IEAT episodes and improving outcomes in trauma patients. Patients admitted with VAP over 36-months were identified and stratified by gender, age, severity of shock, and injury severity. Outcomes included number of IEAT episodes, ventilator days, intensive care unit days, hospital days, and mortality. Three hundred and ninety-three patients with 668 VAP episodes were identified. There were 144 (22%) IEAT episodes: significantly reduced compared with our previous study (39%) (P < 0.001). Patients were classified by number of IEAT episodes: 0 (n = 271), 1 (n = 98) and > or = 2 (n = 24). Mortality was 12 per cent, 13 per cent, and 38 per cent (P < 0.001), respectively. Multivariable logistic regression identified multiple IEAT episodes as an independent predictor of mortality (odds ratio = 4.7; 95% confidence interval: 1.684-13.162). Multiple IEAT episodes were also associated with prolonged mechanical ventilation and intensive care unit stay (P < 0.001). Trauma patients with multiple IEAT episodes for VAP have increased morbidity and mortality. Adherence to a unit-specific pathway for the empiric management of VAP reduces multiple IEAT episodes. By limiting IEAT episodes, resource utilization and hospital mortality are significantly decreased.

Heparin-Induced Thrombocytopenia

Unfractionated heparin is widely used for numerous clinical situations. A well-known adverse effect of heparin exposure is thrombocytopenia. Heparin-induced thrombocytopenia is a clinicopathologic syndrome that can be associated with severe complications and significant mortality. The pathophysiology of heparin-induced thrombocytopenia includes an immune-mediated reaction to heparin that activates platelets and results in an acquired hypercoagulability. Diagnosis of heparin-induced thrombocytopenia should incorporate clinical signs and symptoms and laboratory testing for heparin-induced thrombocytopenia antibodies. Therapy should include discontinuation of heparin, initiation of a direct thrombin inhibitor, and eventually therapy with warfarin (only after the platelet count is at least 100 x 10(9)/L).

Aerosolised Antibacterials for the Prevention and Treatment of Hospital-Acquired Pneumonia

Aerosolised administration of antibacterials remains theoretically attractive for the prevention and treatment of hospital-acquired pneumonia (HAP) because of the ability to generate high drug concentrations at the site of infection. There is renewed interest in this area because of the shortcomings of current therapies and increasing multidrug resistance in Gram-negative organisms. Clinical trials of aerosolised or endotracheally administered antibacterials for HAP prevention have generally been positive; however, early trials were hampered by the development of resistance related to indiscriminate use. More recent trials have shown efficacy at HAP prevention without adverse effects on microflora as a result of more limited usage. However, prophylactic aerosolised antibacterials still need to be studied in large randomised trials before they could enter widespread use. The treatment of HAP with aerosolised antibacterials has mostly been reported in case series without control groups. Both early reports with aminoglycosides and the more recent use of colistin have reported very good response rates; even with organisms such as Pseudomonas aeruginosa and Acinetobacter baumannii. Aerosolised antibacterials were almost always added to intravenous therapy. On the basis of these reports, the current HAP guidelines allow the addition of aerosolised antibacterials in selected patients with multidrug-resistant organisms. This seems to be a reasonable recommendation until large trials are performed. Overall, toxicity was relatively low in the publications reviewed. Aerosolised drug administration in mechanically ventilated patients requires attention to a number of factors in order to maximise drug deposition in the lung.

Pharmacokinetic changes in critical illness

Physiologic alterations in critically ill patients can significantly affect the pharmacokinetics of drugs used in the critically ill patient population. Understanding these pharmacokinetic changes is essential relative to optimizing drug therapy. This article outlines the major differences seen in the absorption, distribution, metabolism, and excretion of drugs in critically ill patients. Important strategies for drug therapy dosing and monitoring in these patients are also addressed.

The futility of the clinical pulmonary infection score in trauma patients

INTRODUCTION

The Clinical Pulmonary Infection Score (CPIS) has received much attention recently. Advocates have touted its use for the diagnosis and duration of therapy in patients with ventilator-associated pneumonia (VAP). However, little has been written about its utility in trauma patients. The clinical, physiologic, and radiologic components of the CPIS may be difficult to differentiate from the systemic effects of injury. Quantitative cultures of the lower airway have been shown to be efficacious in differentiating VAP from the systemic inflammatory response syndrome (SIRS). In this study, we evaluated the potential use of CPIS as the sole means for diagnosis of VAP in critically injured patients.

METHODS

Patients were identified from the VAP database maintained in our Level I trauma center. Only those who had CPIS calculated at the time of bronchoscopy with BAL were included. VAP required >or=10 colonies/mL on quantitative BAL for diagnosis. Antibiotic therapy was based on quantitative BAL results. Patients with <10 colonies/mL were diagnosed with SIRS. Sensitivity and specificity of a CPIS>6 for VAP diagnosis (confirmed by BAL) were calculated.

RESULTS

In all, 158 patients underwent 285 BALs. The overall incidence for VAP was 42%. Patients with episodes of VAP and SIRS were well matched for age, Injury Severity Score, APACHE II score, and Glasgow Coma Scale score. The average CPIS was 6.8 in patients with SIRS and 6.9 for those with VAP. Using a CPIS>6 as the threshold for VAP only yielded a sensitivity of 61% and a specificity of 43%.

CONCLUSIONS

CPIS cannot differentiate VAP from SIRS in critically injured patients. Using CPIS to initiate antibiotic therapy in trauma patients could be harmful. Whether CPIS is useful to determine duration of antibiotic therapy is unknown.

Sequence variants of the DRD4 gene in autism: further evidence that rare DRD4 7R haplotypes are ADHD specific

A high prevalence of rare dopamine receptor D4 (DRD4) alleles in children diagnosed with attention-deficit hyperactivity disorder (ADHD) has been reported [Grady et al., 2003]. In this prior study, extensive resequencing/haplotype data of the DRD4 locus was used to suggest that population stratification was not the explanation for the high prevalence of rare alleles. In the current study, DNA resequencing/haplotyping was conducted on 136 DRD4 alleles obtained from autism probands, collected from the same geographic population as the prior ADHD probands (Orange County, CA). A number of studies have suggested that the susceptibility genes underlying these two disorders might partially overlap. Rare DRD4 variants were not uncovered in this autism sample beyond that expected by chance. These results suggest strongly that the high prevalence of rare DRD4 alleles in ADHD probands is due to ascertainment of the sample by diagnosis of ADHD.

Dopamine in drug abuse and addiction: results from imaging studies and treatment implications

The involvement of dopamine in drug reinforcement is well recognized but its role in drug addiction is much less clear. Imaging studies have shown that the reinforcing effects of drugs of abuse in humans are contingent upon large and fast increases in dopamine that mimic but exceed in the intensity and duration those induced by dopamine cell firing to environmental events. In addition, imaging studies have also documented a role of dopamine in motivation, which appears to be encoded both by fast as well as smooth DA increases. Since dopamine cells fire in response to salient stimuli, the supraphysiological activation by drugs is likely to be experienced as highly salient (driving attention, arousal conditioned learning and motivation) and may also reset the thresholds required for environmental events to activate dopamine cells. Indeed, imaging studies have shown that in drug-addicted subjects, dopamine function is markedly disrupted (decreases in dopamine release and in dopamine D2 receptors in striatum) and this is associated with reduced activity of the orbitofrontal cortex (neuroanatomical region involved with salience attribution and motivation and implicated in compulsive behaviors) and the cingulate gyrus (neuroanatomical region involved with inhibitory control and attention and implicated in impulsivity). However, when addicted subjects are exposed to drug-related stimuli, these hypoactive regions become hyperactive in proportion to the expressed desire for the drug. We postulate that decreased dopamine function in addicted subjects results in decreased sensitivity to nondrug-related stimuli (including natural reinforcers) and disrupts frontal inhibition, both of which contribute to compulsive drug intake and impaired inhibitory control. These findings suggest new strategies for pharmacological and behavioral treatments, which focus on enhancing DA function and restoring brain circuits disrupted by chronic drug use to help motivate the addicted subject in activities that provide alternative sources of reinforcement, counteract conditioned responses, enhance their ability to control their drive to take drugs and interfere with their compulsive administration.

The genetic architecture of selection at the human dopamine receptor D4 (DRD4) gene locus

Associations of the seven-repeat (7R) allele of the human dopamine receptor D4 (DRD4) gene with both the personality trait of novelty seeking and attention deficit/hyperactivity disorder have been reported. Recently, on the basis of the unusual DNA sequence organization of the DRD4 7R 48-bp tandem repeat (VNTR), we proposed that the 7R allele originated as a rare mutational event that increased to high frequency by positive selection. We now have resequenced the entire DRD4 locus from 103 individuals homozygous for 2R, 4R, or 7R variants of the VNTR, a method developed to directly estimate haplotype diversity. DNA from individuals of African, European, Asian, North and South American, and Pacific Island ancestry were used. 4R/4R homozygotes exhibit little linkage disequilibrium (LD) over the region examined, with more polymorphisms observed in DNA samples from African individuals. In contrast, the evidence for strong LD surrounding the 7R allele is dramatic, with all 7R/7R individuals (including those from Africa) exhibiting the same alleles at most polymorphic sites. By intra-allelic comparison at 18 high-heterozygosity sites spanning the locus, we estimate that the 7R allele arose prior to the upper Paleolithic era (approximately 40000-50000 years ago). Further, the pattern of recombination at these polymorphic sites is the pattern expected for selection acting at the 7R VNTR itself, rather than at an adjacent site. We propose a model for selection at the DRD4 locus consistent with these observed LD patterns and with the known biochemical and physiological differences between receptor variants.