The "fever workup" and respiratory culture practice in critically ill trauma patients

Fever and infections in surgical intensive care: an American Association for the Surgery of Trauma Critical Care Committee clinical consensus document

The evaluation and workup of fever and the use of antibiotics to treat infections is part of daily practice in the surgical intensive care unit (ICU). Fever can be infectious or non-infectious; it is important to distinguish between the two entities wherever possible. The evidence is growing for shortening the duration of antibiotic treatment of common infections. The purpose of this clinical consensus document, created by the American Association for the Surgery of Trauma Critical Care Committee, is to synthesize the available evidence, and to provide practical recommendations. We discuss the evaluation of fever, the indications to obtain cultures including urine, blood, and respiratory specimens for diagnosis of infections, the use of procalcitonin, and the decision to initiate empiric antibiotics. We then describe the treatment of common infections, specifically ventilator-associated pneumonia, catheter-associated urinary infection, catheter-related bloodstream infection, bacteremia, surgical site infection, intra-abdominal infection, ventriculitis, and necrotizing soft tissue infection.

Unraveling quad fever: Severe hyperthermia after traumatic cervical spinal cord injury

PURPOSE

There are many infectious and inflammatory causes for elevated core-body temperatures, though they rarely pass 40 ℃ (104 ℉). The term "quad fever" is used for extreme hyperpyrexia in the setting of acute cervical spinal cord injuries (SCIs). The traditional methods of treating hyperpyrexia are often ineffective and reported morbidity and mortality rates approach 100%. This study aims to identify the incidence of elevated temperatures in SCIs at our institution and assess the effectiveness of using a non-invasive dry water temperature management system as a treatment modality with mortality.

METHODS

A retrospective analysis of acute SCI patients requiring surgical intensive care unit admission who experienced fevers ≥ 40 ℃ (104 ℉) were compared to patients with maximum temperatures < 40 ℃. Patients ≥18 years old who sustained an acute traumatic SCI were included in this study. Patients who expired in the emergency department; had a SCI without radiologic abnormality; had neuropraxia; were admitted to any location other than the surgical intensive care unit; or had positive blood cultures were excluded. SAS 9.4 was used to conduct statistical analysis.

RESULTS

Over the 9-year study period, 35 patients were admitted to the surgical intensive care unit with a verified SCI. Seven patients experienced maximum temperatures of ≥ 40 ℃. Six of those patients were treated with the dry water temperature management system with an overall mortality of 57.1% in this subgroup. The mortality rate for the 28 patients who experienced a maximum temperature of ≤ 40 ℃ was 21.4% (p = 0.16).

CONCLUSION

The diagnosis of quad fever should be considered in patients with cervical SCI in the presence of hyperthermia. In this study, there was no significant difference in mortality between quad fever patients treated with a dry water temperature management system versus SCI patients without quad fever. The early use of a dry water temperature management system appears to decrease the mortality rate of quad fever.

An overview of cytokines and heat shock response in polytraumatized patients

Early after injury, local tissue damage induces a local and systemic inflammatory response that activates the immune system and leads to the development of systemic inflammatory response syndrome (SIRS). This post-traumatic response often results in uncontrolled release of inflammatory mediators and over-activation of the immune system, which occasionally results in multiple organ dysfunction syndrome (MODS). In parallel, a state of immunosuppression develops. This counter-regulating suppression of different cellular and humoral immune functions has been termed "compensatory anti-inflammatory response syndrome (CARS)." Both SIRS and CARS occur simultaneously even in the initial phase after injury. Pro- and anti-inflammatory cytokines have been suggested to play a major role in development of SIRS, although the degree of involvement of the different cytokines is quite disparate. While TNF-α and IL-1β are quite irrelevant for predicting organ dysfunction, IL-6 is the parameter that best predicts mortality. The hyperinflammatory state seems to be the cause of post-traumatic immunosuppression and heat shock proteins (HSPs), which have been proposed as one of the endogenous stimuli for the deterioration of the immune system acting as danger-associated molecular patterns (DAMPs). Extracellular HSPA1A released from injured tissues increase up to ten times immediately after trauma and even more in patients with MODS. It has powerful immune properties that could contribute to post-traumatic immunosuppression through several mechanisms that have been previously described, so HSPs could represent trauma-associated immunomodulatory mediators. For this reason, HSPA1A has been suggested to be a helpful early prognostic biomarker of trauma after severe injury: serial quantification of serum HSPA1A and anti-Hsp70 concentrations in the first hours after trauma is proposed to be used as a predictive biomarker of MODS and immunosuppression development in polytraumatized patients.

Inadequacy of Algorithmic Ventilator-Associated Pneumonia Diagnosis in Acute Care Surgery

Clinical utility of algorithms to diagnose ventilator-associated pneumonia (VAP) in surgical patients has not been established. We aimed to test the diagnostic accuracy of two established methods to reliably diagnose VAP in acutely ill and injured surgical patients. After institutional review board approval, we prospectively collected data on 508 mechanically ventilated acute care surgery patients. Microbiologic samples were taken daily from all patients. Demographics, clinical, laboratory, and radiographic data were collected. The Johanson Criteria (JC) and Clinical Pulmonary Infection Score (CPIS) were calculated and analyzed. Sensitivity, specificity, and positive predictive values (PPV) and negative predictive value (NPV) were calculated in comparison to positive respiratory cultures. Of the 508 patients, 312 (61.4%) were acutely injured; emergent general surgery was performed in 141 (27.8%) patients, and 54 (10.6%) underwent elective operation. Positive respiratory cultures were identified in 198 (39%) of the 508 patients. JC diagnosed VAP in 291 (57.3%) patients (sensitivity 82.8%, specificity 59%, PPV 56.4%, NPV 84.3%, accuracy 68.3%). The CPIS resulted in 189 (37.2%) VAP diagnoses (sensitivity 61.1%, specificity 78.1%, PPV 64%, NPV 75.9%, and accuracy 71.5%). To address the inaccuracy of the algorithms, concordance testing was performed on the data to evaluate correlation between the algorithmic VAP diagnosis criteria and respiratory culture data. Nonconcordance with culture data diagnosis was identified with both JC (rho 0.41) and CPIS (rho 0.41). Sensitivity, specificity, PPV and NPV, and accuracy of both established clinical formulas was unacceptably low in acute care surgery patients.

Current Pneumonia Surveillance Methodology: Similar Underestimation in Trauma and Surgical Patients in the Intensive Care Unit

BACKGROUND

In 2013, the Centers for Disease Control and Prevention (CDC) developed new surveillance definitions for ventilator-associated events (VAE), leading to concerns that hospitals may be underreporting the true incidence of ventilator-associated pneumonias (VAPs). We sought to compare rates of clinically diagnosed VAP with CDC defined possible VAPs (PVAPs) in patients with a VAE in the surgical/trauma intensive care unit (STICU).

HYPOTHESIS

Significant difference exists between rates of clinical VAP and PVAP in patients with at least one VAE.

PATIENTS AND METHODS

All STICU patients with ≥1 VAE, between 1/1/2013 and 10/31/2015 were identified. Age, length of stay (LOS), ICU and ventilator days were collected.

RESULTS

There were 134 patients who had ≥1 VAE. Mean age was 54.3 (±17.1) years. Mean LOS, median ICU, and median ventilator days were 26.3 (±14.1), 21.0 (17.0-33.0), and 17.0 (12.8-24.0) days, respectively. There were 68 cases of clinically diagnosed VAP, but only 37% met PVAP criteria. We compared 43 cases of clinical VAP, not meeting PVAP criteria, with the 25 PVAPs. Both groups had similar outcomes. The PVAPs were more likely to have an abnormal temperature (48.0% vs. 14.0%, p = 0.004), abnormal white blood cell count (84.0% vs. 18.6%, p < 0.001), or new antibiotic agent initiated (100% vs. 18.6%, p < 0.001) as VAE triggers. Comparison of the 93 trauma and 41 surgical patients demonstrated trauma patients were younger (51.2 vs. 61.5 y, p = 0.001), but had similar outcomes and rates of clinical VAP (48.4% and 43.9%, p = NS). Only 20.4% of trauma and 14.6% of surgical patients, however, had a PVAP reported. For patients with at least one VAE, the sensitivity and specificity for PVAP detecting VAP was 36.8% and 96.0%, respectively.

CONCLUSION

The new CDC definition for PVAP grossly underestimates the clinical diagnosis of VAP and reports less than a third of the patients treated for VAP. Reporting differences were similar for trauma and surgical patients.

Management of Postoperative Fever in Adult Cardiac Surgical Patients

Postoperative fever after cardiac surgery is a common occurrence. Most fevers are benign and self-limiting resulting from inflammation caused by surgical trauma and blood contact with cardiopulmonary bypass circuit resulting in the release of cytokines. Only a small percentage of time is postoperative fever due to an infection complicating surgery. The presence of fever frequently triggers a battery of diagnostic tests that are costly, could expose the patient to unnecessary risks, and can produce misleading or inconclusive results. It is therefore important that fever be evaluated in a systematic, prudent, clinically appropriate, and cost-effective manner. This article focuses on the current evidence regarding pathophysiology, incidence, causes, evaluation, and management of fever in postoperative adult cardiac surgical patients.

Pyrexia: aetiology in the ICU

Elevation in core body temperature is one of the most frequently detected abnormal signs in patients admitted to adult ICUs, and is associated with increased mortality in select populations of critically ill patients. The definition of an elevated body temperature varies considerably by population and thermometer, and is commonly defined by a temperature of 38.0 °C or greater. Terms such as hyperthermia, pyrexia, and fever are often used interchangeably. However, strictly speaking hyperthermia refers to the elevation in body temperature that occurs without an increase in the hypothalamic set point, such as in response to specific environmental (e.g., heat stroke), pharmacologic (e.g., neuroleptic malignant syndrome), or endocrine (e.g., thyrotoxicosis) stimuli. On the other hand, pyrexia and fever refer to the classical increase in body temperature that occurs in response to a vast list of infectious and noninfectious aetiologies in association with an increase in the hypothalamic set point. In this review, we examine the contemporary literature investigating the incidence and aetiology of pyrexia and hyperthermia among medical and surgical patients admitted to adult ICUs with or without an acute neurological condition. A temperature greater than 41.0 °C, although occasionally observed among patients with infectious or noninfectious pyrexia, is more commonly observed in patients with hyperthermia. Most episodes of pyrexia are due to infections, but incidence estimates of infectious and noninfectious aetiologies are limited by studies with small sample size and inconsistent reporting of noninfectious aetiologies. Pyrexia commonly triggers a full septic work-up, but on its own is a poor predictor of culture-positivity. In order to improve culturing practices, and better guide the diagnostic approach to critically ill patients with pyrexia, additional research is required to provide more robust estimates of the incidence of infectious and noninfectious aetiologies, and their relationship to other clinical features (e.g., leukocytosis). In the meantime, using existing literature, we propose an approach to identifying the aetiology of pyrexia in critically ill adults.

Where's the difference? Presentation of nosocomial infection in critically ill trauma versus general surgery patients

BACKGROUND

Diagnosing infection efficiently is integral to managing critically ill patients. Knowing if and how trauma and general surgery patients differ in their presentation of new infectious complications could be useful. We hypothesized these populations would differ in presentation in the intensive care unit (ICU).

METHODS

We analyzed data collected prospectively from all 1,657 trauma and general surgery patients admitted to the surgical and trauma ICU (STICU) over a 21-month period. Clinical data from the first day of a newly diagnosed infection were compared for trauma (82% of the series) and general surgery (18%) patients.

RESULTS

A total of 10,424 STICU days were included, and 267 nosocomial infections were diagnosed. Trauma patients were younger (50 vs. 62 years; p<0.001) and more likely to be male (78% vs. 46%; p<0.001) than were general surgery patients. Similar percentages of the two groups were infected (11% and 13%, respectively), and infections occurred after a similar number of days in the STICU. The mean maximum temperature on the day prior to diagnosis was higher in trauma patients (38.4°C vs. 37.7°C; p<0.001), and the mean leukocyte count was lower (13,500 vs. 15,800 10(6)/L; p=0.013). General surgery patients were more likely to be hypotensive (13% vs. 2%; p=0.002) and to have a positive fluid balance >2 L on the first day of infection (27% vs. 13%; p=0.02). Respiratory infections were more common in trauma patients (40% vs. 7%; p<0.001), and urinary tract infections were less common (19% vs. 36%; p=0.011).

CONCLUSION

Differences exist in how new infections manifest in trauma and general surgery patients in the ICU. General surgery patients appeared sicker on their first day of infection, as evidenced by a higher leukocyte count, lower blood pressure, and substantial positive fluid balance. Intensivists may need differing thresholds for triggering infection workups when employed in a mixed unit.

The evidence base for nursing care and monitoring of patients during therapeutic temperature management

Therapeutic temperature management (TTM) is fast becoming a primary management strategy for a variety of medical conditions treated in critical care settings throughout the world. Nurses who provide direct care and who are tasked with developing multidisciplinary protocols and pathways are struggling to collate evidence from which to support specific nursing interventions. The aim of this project was to create the first comprehensive set of evidence-based guidelines specific to nursing care of the patient for whom TTM is medically necessary. Evidence-based nursing practice summaries are provided for nine nursing content areas: interventions to manage temperature, monitoring temperature, neurologic, cardiac, pulmonary, skin care, gastrointestinal/endocrine, laboratory findings, and general considerations for nursing care.

Enhancing the fever workup utilizing a multi-technique modeling approach to diagnose infections more accurately

BACKGROUND

Differentiation between infectious and non-infectious etiologies of the systemic inflammatory response syndrome (SIRS) in trauma patients remains elusive. We hypothesized that mathematical modeling in combination with computerized clinical decision support would assist with this differentiation. The purpose of this study was to determine the capability of various mathematical modeling techniques to predict infectious complications in critically ill trauma patients and compare the performance of these models with a standard fever workup practice (identifying infections on the basis of fever or leukocytosis).

METHODS

An 18-mo retrospective database was created using information collected daily from critically ill trauma patients admitted to an academic surgical and trauma intensive care unit. Two hundred forty-three non-infected patient-days were chosen randomly to combine with the 243 infected-days, which created a modeling sample of 486 patient-days. Utilizing ten variables known to be associated with infectious complications, decision trees, neural networks, and logistic regression analysis models were created to predict the presence of urinary tract infections (UTIs), bacteremia, and respiratory tract infections (RTIs). The data sample was split into a 70% training set and a 30% testing set. Models were compared by calculating sensitivity, specificity, positive predictive value, negative predictive value, overall accuracy, and discrimination.

RESULTS

Decision trees had the best modeling performance, with a sensitivity of 83%, an accuracy of 82%, and a discrimination of 0.91 for identifying infections. Both neural networks and decision trees outperformed logistic regression analysis. A second analysis was performed utilizing the same 243 infected days and only those non-infected patient-days associated with negative microbiologic cultures (n = 236). Decision trees again had the best modeling performance for infection identification, with a sensitivity of 79%, an accuracy of 83%, and a discrimination of 0.87.

CONCLUSION

The use of mathematical modeling techniques beyond logistic regression can improve the robustness and accuracy of predicting infections in critically ill trauma patients. Decision tree analysis appears to have the best potential to use in assisting physicians in differentiating infectious from non-infectious SIRS.