C. William Hanson

Effects of an organized critical care service on outcomes and resource utilization: A cohort study

OBJECTIVE To determine whether the presence of an on-site, organized, supervised critical service improves care and decreases resource utilization. DESIGN The study compared two patient cohorts admitted to a surgical intensive care unit during the same period of time. The study cohort was cared for by an on-site critical care team supervised by an intensivist. The control cohort was cared for by a team with patient care responsibilities in multiple sites supervised by a general surgeon. The main outcome measures were duration of stay, resource utilization, and complication rate. SETTING Study patients were general surgical patients in an academic medical center. RESULTS Despite having higher Acute Physiology and Chronic Health Evaluation II scores, patients cared for by the critical care service spent less time in the surgical intensive care unit, used fewer resources, had fewer complications and had lower total hospital charges. The difference between the two cohorts was most evident in patients with the worst APACHE II score. CONCLUSIONS Critical care interventions are expensive and have a narrow safety margin. It is essential to develop structured and validated approaches to study the delivery of this resource. In this study, the critical care service model performed favorably both in terms of quality and cost.

Artificial intelligence applications in the intensive care unit

ObjectiveTo review the history and current applications of artificial intelligence in the intensive care unit. Data SourcesThe MEDLINE database, bibliographies of selected articles, and current texts on the subject. Study SelectionThe studies that were selected for review used artificial intelligence tools for a variety of intensive care applications, including direct patient care and retrospective database analysis. Data ExtractionAll literature relevant to the topic was reviewed. Data SynthesisAlthough some of the earliest artificial intelligence (AI) applications were medically oriented, AI has not been widely accepted in medicine. Despite this, patient demographic, clinical, and billing data are increasingly available in an electronic format and therefore susceptible to analysis by intelligent software. Individual AI tools are specifically suited to different tasks, such as waveform analysis or device control. ConclusionsThe intensive care environment is particularly suited to the implementation of AI tools because of the wealth of available data and the inherent opportunities for increased efficiency in inpatient care. A variety of new AI tools have become available in recent years that can function as intelligent assistants to clinicians, constantly monitoring electronic data streams for important trends, or adjusting the settings of bedside devices. The integration of these tools into the intensive care unit can be expected to reduce costs and improve patient outcomes.

Stroke After Aortic Valve Surgery Results From a Prospective Cohort

Background— The incidence and impact of clinical stroke and silent radiographic cerebral infarction complicating open surgical aortic valve replacement (AVR) are poorly characterized. Methods and Results— We performed a prospective cohort study of subjects ≥65 years of age who were undergoing AVR for calcific aortic stenosis. Subjects were evaluated by neurologists preoperatively and postoperatively and underwent postoperative magnetic resonance imaging. Over a 4-year period, 196 subjects were enrolled at 2 sites (mean age, 75.8±6.2 years; 36% women; 6% nonwhite). Clinical strokes were detected in 17%, transient ischemic attack in 2%, and in-hospital mortality was 5%. The frequency of stroke in the Society for Thoracic Surgery database in this cohort was 7%. Most strokes were mild; the median National Institutes of Health Stroke Scale was 3 (interquartile range, 1–9). Clinical stroke was associated with increased length of stay (median, 12 versus 10 days; P=0.02). Moderate or severe stroke (National Institutes of Health Stroke Scale ≥10) occurred in 8 (4%) and was strongly associated with in-hospital mortality (38% versus 4%; P=0.005). Of the 109 stroke-free subjects with postoperative magnetic resonance imaging, silent infarct was identified in 59 (54%). Silent infarct was not associated with in-hospital mortality or increased length of stay. Conclusions— Clinical stroke after AVR was more common than reported previously, more than double for this same cohort in the Society for Thoracic Surgery database, and silent cerebral infarctions were detected in more than half of the patients undergoing AVR. Clinical stroke complicating AVR is associated with increased length of stay and mortality.Background— The incidence and impact of clinical stroke and silent radiographic cerebral infarction complicating open surgical aortic valve replacement (AVR) are poorly characterized. Methods and Results— We performed a prospective cohort study of subjects ≥65 years of age who were undergoing AVR for calcific aortic stenosis. Subjects were evaluated by neurologists preoperatively and postoperatively and underwent postoperative magnetic resonance imaging. Over a 4-year period, 196 subjects were enrolled at 2 sites (mean age, 75.8±6.2 years; 36% women; 6% nonwhite). Clinical strokes were detected in 17%, transient ischemic attack in 2%, and in-hospital mortality was 5%. The frequency of stroke in the Society for Thoracic Surgery database in this cohort was 7%. Most strokes were mild; the median National Institutes of Health Stroke Scale was 3 (interquartile range, 1–9). Clinical stroke was associated with increased length of stay (median, 12 versus 10 days; P =0.02). Moderate or severe stroke (National Institutes of Health Stroke Scale ≥10) occurred in 8 (4%) and was strongly associated with in-hospital mortality (38% versus 4%; P =0.005). Of the 109 stroke-free subjects with postoperative magnetic resonance imaging, silent infarct was identified in 59 (54%). Silent infarct was not associated with in-hospital mortality or increased length of stay. Conclusions— Clinical stroke after AVR was more common than reported previously, more than double for this same cohort in the Society for Thoracic Surgery database, and silent cerebral infarctions were detected in more than half of the patients undergoing AVR. Clinical stroke complicating AVR is associated with increased length of stay and mortality. # CLINICAL PERSPECTIVE {#article-title-47}

Electronic nose prediction of a clinical pneumonia score: Biosensors and microbes

Background: The authors performed a prospective study to determine whether breath test analysis using an electronic nose correlates with a clinical pneumonia score. Methods: Exhaled gas was sampled from the expiratory limb of the ventilator in mechanically ventilated surgical intensive care patients and assayed with the electronic nose. Components of a clinical pneumonia score were recorded concurrently. Results: The score predicted by the electronic nose showed good correlation with the actual pneumonia score (r2 = 0.81). Bland Altman analysis showed a mean bias of 0.0 (limits ± 2.6). Conclusions: The electronic nose is a new biosensor technology that correlates with a clinical pneumonia score.

Diagnosis of Pneumonia With an Electronic Nose: Correlation of Vapor Signature With Chest Computed Tomography Scan Findings

Objectives/Hypothesis: The electronic nose is a sensor of volatile molecules that is useful in the analysis of expired gases. The device is well suited to testing the breath of patients receiving mechanical ventilation and is a potential diagnostic adjunct that can aid in the detection of patients with ventilator‐associated pneumonia.

Medical applications of electronic nose technology

Electronic nose technology has been developed over the past 15 years in the field of chemistry as an electronic equivalent of the biologic mechanism of smell. Since its inception, it has been well recognized that there is great potential in applying this technology to the field of medicine. This review discusses those areas of medicine in which electronic nose technology has been applied. For each area, this review addresses the scope of the medical problem that has been studied, how the electronic nose technology may help address the medical problem, and the results of such studies to date. Next generation electronic noses will be refined to better analyze specific disease states. This will require further evaluation of the specific volatiles to be tested. This information may then be brought to bear on refinement of the chemistry of the electronic nose sensors, making them more sensitive and specific for the particular disease of interest. The ultimate goal of work in this arena is to make an electronic nose that is portable, fast, inexpensive and, therefore, suitable for use in the examination room or at the bedside, making it facile as a diagnostic tool.

Urgent paralysis and intubation of trauma patients : is it safe ?

Physicians, fearful of an increase in the incidence of intubation mishaps (IMs) and pulmonary complications (PUCs), have been reluctant to use paralysis and intubation (PI) outside the OR. This study examines the correlations between PI, IM, and PUC. Since 1987, we have used PI when complex injury or combative behavior warranted. From January through December 1989, 851 patients meeting major trauma triage guidelines were evaluated. The medical records of 231 patients (27%) who underwent PI within 8 hours of admission were reviewed; 27 patients were eliminated because of incomplete records. The indications for PI were emergency surgery (131), airway control (30), combativeness (24), and hyperventilation (19). The location was the OR (121), ED (82), other (1). Presence or absence of IM was documented in 198 of 204 charts: Twenty-four IMs (12%) occurred--14 multiple attempts, seven aspirations, three esophageal intubations. Frequency of IM was not statistically related to PI location (Fishers exact test), AIS, or ISS. In 194 of 204 patients who survived at least 24 hours, there were 15 PUCs (8%): eight pneumonia, five persistent infiltrates, two severe atelectases. No deaths were related to IM or PUC. There was no statistical relationship between IM and PUC (Fishers exact test). However, patients with PUCs had a significantly higher AIS-chest score (2.9 +/- 1.7 vs. 0.9 +/- 1.5) (p < 0.0005, Students t test) and ISS (27.3 +/- 9.6 vs. 14.5 +/- 10.8) (p < 0.0005, Students t test). In our hands, PI is associated with low morbidity, no mortality, and can be safely used to facilitate injury management or to control combative behavior.

Improvement in Oxygenation by Phenylephrine and Nitric Oxide in Patients with Adult Respiratory Distress Syndrome

Background: Inhaled nitric oxide (NO), a selective vasodilator, improves oxygenation in many patients with adult respiratory distress syndrome (ARDS). Vasoconstrictors may also improve oxygenation, possibly by enhancing hypoxic pulmonary vasoconstriction. This study compared the effects of phenylephrine, NO, and their combination in patients with ARDS. Methods: Twelve patients with ARDS (PaO2 /FIO2 180; Murray score 2) were studied. Each patient received three treatments in random order: intravenous phenylephrine, 50–200 micro gram/min, titrated to a 20% increase in mean arterial blood pressure; inhaled NO, 40 ppm; and the combination (phenylephrine + NO). Hemodynamics and blood gas measurements were made during each treatment and at pre‐ and posttreatment baselines. Results: All three treatments improved PaO2 overall. Six patients were “phenylephrine‐responders” (Delta PaO2 > 10 mmHg), and six were “phenylephrine‐nonresponders.” In phenylephrine‐responders, the effect of phenylephrine was comparable with that of NO (PaO2 from 105 +/‐ 10 to 132 +/‐ 14 mmHg with phenylephrine, and from 110 +/‐ 14 to 143 +/‐ 19 mmHg with NO), and the effect of phenylephrine + NO was greater than that of either treatment alone (PaO2 from 123 +/‐ 13 to 178 +/‐ 23 mmHg). In phenylephrine‐nonresponders, phenylephrine did not affect Pa sub O2, and the effect of phenylephrine + NO was not statistically different from that of NO alone (PaO2 from 82 +/‐ 12 to 138 +/‐ 28 mmHg with NO; from 84 +/‐ 12 to 127 +/‐ 23 mmHg with phenylephrine + NO). Data are mean +/‐ SEM. Conclusions: Phenylephrine alone can improve PaO2 in patients with ARDS. In phenylephrine‐responsive patients, phenylephrine augments the improvement in PaO2 seen with inhaled NO. These results may reflect selective enhancement of hypoxic pulmonary vasoconstriction by phenylephrine, which complements selective vasodilation by NO.

Correlation of pneumonia score with electronic nose signature : A prospective study

Objectives: Ventilator-associated pneumonia (VAP) is a frequent complication in patients in surgical intensive care units. Pneumonia scores, chest radiography, and bronchoscopy are all employed, but there is no gold standard test for the diagnosis of VAP. The electronic nose, a sensor of volatile molecules, is well suited to testing the breath of mechanically ventilated patients. Our objective was to determine the potential use of an electronic nose as a diagnostic adjunct in the detection of VAP. Methods: We performed a prospective study of mechanically ventilated patients in a surgical intensive care unit. Clinical data, including temperature, white blood cell count, character and quantity of tracheal secretions, ratio of partial pressure of arterial oxygen to fraction of inspired oxygen, and chest radiographs, were collected, and a pneumonia score between 0 and 10 was calculated. Exhaled gas was sampled from the expiratory limb of the ventilator circuit. The gases were assayed with a commercially available electronic nose. Multidimensional data reduction analysis was used to analyze the results. Results: Forty-four patients were studied. Fifteen patients had pneumonia scores of 7 or greater, and 29 patients had scores of 6 or less. With Fisher discriminant analysis and K—nearest neighbor analysis, the electronic nose was able to discriminate between the two groups. Conclusions: The electronic nose is a new technology that is inexpensive, noninvasive, and portable. We demonstrate its ability to predict pneumonia, based on a well-recognized scoring system. This technology promises to serve as a diagnostic adjunct in the management of VAP.

Critical Care Nurse Practitioners Improve Compliance With Clinical Practice Guidelines in “semiclosed” Surgical Intensive Care Unit

This prospective study examined whether the integration of acute care nurse practitioners (ACNP) in a “semiclosed” surgical intensive care unit (SICU) model increased compliance with clinical practice guidelines (CPG). Patients were admitted to critical care services with a (a) “semiclosed”/ACNP team or (b) “mandatory consultation”/non-ACNP team. CPG compliance was significantly higher (P < .05) on the “semiclosed”/ACNP team for all 3 CPGs examined in the study.