Predicting mortality from acetaminophen poisoning shortly after hospital presentation.

AIMS: Early identification of patients likely to die after acetaminophen (APAP) poisoning remains challenging. We sought to compare the sensitivity and time to fulfilment (latency) of established prognostic criteria. METHODS: Three physician toxicologists independently classified every in-hospital death associated with APAP overdose from eight large Canadian cities over three decades using the Relative Contribution to Fatality scale from the American Association of Poison Control Centres. The sensitivity and latency were calculated for each of the following criteria: King's College Hospital (KCH), Model for End Stage Liver Disease (MELD) ≥33, lactate ≥3.5 mmol/L, phosphate ≥1.2 mmol/L 48+ hours post-ingestion, as well as combinations thereof. RESULTS: A total of 162 in-hospital deaths were classified with respect to APAP as follows: 26 Undoubtedly, 40 Probably, 27 Contributory, 14 Probably not, 25 Clearly not, and 30 Unknown. Cases from the first three classes (combined into n = 93 "APAP deaths") typically presented with supratherapeutic APAP concentrations, hepatotoxicity, acidaemia, coagulopathy and/or encephalopathy, and began antidotal treatment a median of 12 hours (IQR 3.4-30 h) from the end of ingestion. Among all patients deemed "APAP deaths", meeting either KCH or lactate criteria demonstrated the highest sensitivity (94%; 95% CI 86-98%), and the shortest latency from hospital arrival to criterion fulfilment (median 4.2 h; IQR 1.0-16 h). In comparison, the MELD criterion demonstrated a substantially lower sensitivity (55%; 43-66%) and longer latency (52 h; 4.4-∞ h, where "∞" denotes death prior to criterion becoming positive). CONCLUSIONS: Meeting either KCH or serum lactate criteria identifies most patients who die from acetaminophen poisoning at or shortly after hospital presentation.

Picking the Right Tool for the Job: A Reliability Study of 4 Assessment Tools for Central Venous Catheter Insertion.

BACKGROUND: Determining procedural competence requires psychometrically sound assessment tools. A variety of instruments are available to determine procedural performance for central venous catheter (CVC) insertion, but it is not clear which ones should be used in the context of competency-based medical education. OBJECTIVE: We compared several commonly used instruments to determine which should be preferentially used to assess competence in CVC insertion. METHODS: Junior residents completing their first intensive care unit rotation between July 31, 2006, and March 9, 2007, were video-recorded performing CVC insertion on task trainer mannequins. Between June 1, 2016, and September 30, 2016, 3 experienced raters judged procedural competence on the historical video recordings of resident performance using 4 separate tools, including an itemized checklist, Objective Structured Assessment of Technical Skills (OSATS), a critical error assessment tool, and the Ottawa Surgical Competency Operating Room Evaluation (O-SCORE). Generalizability theory (G-theory) was used to compare the performance characteristics among the tools. A decision study predicted the optimal testing environment using the tools. RESULTS: At the time of the original recording, 127 residents rotated through intensive care units at the University of Calgary, Alberta, Canada. Seventy-seven of them (61%) met inclusion criteria, and 55 of those residents (71%) agreed to participate. Results from the generalizability study (G-study) demonstrated that scores from O-SCORE and OSATS were the most dependable. Dependability could be maintained for O-SCORE and OSATS with 2 raters. CONCLUSIONS: Our results suggest that global rating scales, such as the OSATS or the O-SCORE tools, should be preferentially utilized for assessment of competence in CVC insertion.

The accuracy of pulse oximetry in emergency department patients with severe sepsis and septic shock: a retrospective cohort study.

BACKGROUND: Pulse oximetry is routinely used to continuously and noninvasively monitor arterial oxygen saturation (SaO2) in critically ill patients. Although pulse oximeter oxygen saturation (SpO2) has been studied in several patient populations, including the critically ill, its accuracy has never been studied in emergency department (ED) patients with severe sepsis and septic shock. Sepsis results in characteristic microcirculatory derangements that could theoretically affect pulse oximeter accuracy. The purposes of the present study were twofold: 1) to determine the accuracy of pulse oximetry relative to SaO2 obtained from ABG in ED patients with severe sepsis and septic shock, and 2) to assess the impact of specific physiologic factors on this accuracy. METHODS: This analysis consisted of a retrospective cohort of 88 consecutive ED patients with severe sepsis who had a simultaneous arterial blood gas and an SpO2 value recorded. Adult ICU patients that were admitted from any Calgary Health Region adult ED with a pre-specified, sepsis-related admission diagnosis between October 1, 2005 and September 30, 2006, were identified. Accuracy (SpO2 - SaO2) was analyzed by the method of Bland and Altman. The effects of hypoxemia, acidosis, hyperlactatemia, anemia, and the use of vasoactive drugs on bias were determined. RESULTS: The cohort consisted of 88 subjects, with a mean age of 57 years (19 - 89). The mean difference (SpO2 - SaO2) was 2.75% and the standard deviation of the differences was 3.1%. Subgroup analysis demonstrated that hypoxemia (SaO2 < 90) significantly affected pulse oximeter accuracy. The mean difference was 4.9% in hypoxemic patients and 1.89% in non-hypoxemic patients (p < 0.004). In 50% (11/22) of cases in which SpO2 was in the 90-93% range the SaO2 was <90%. Though pulse oximeter accuracy was not affected by acidoisis, hyperlactatementa, anemia or vasoactive drugs, these factors worsened precision. CONCLUSIONS: Pulse oximetry overestimates ABG-determined SaO2 by a mean of 2.75% in emergency department patients with severe sepsis and septic shock. This overestimation is exacerbated by the presence of hypoxemia. When SaO2 needs to be determined with a high degree of accuracy arterial blood gases are recommended.

Simulation-based training in critical resuscitation procedures improves residents' competence.

OBJECTIVE: Residents must become proficient in a variety of procedures. The practice of learning procedural skills on patients has come under ethical scrutiny, giving rise to the concept of simulation-based medical education. Resident training in a simulated environment allows skill acquisition without compromising patient safety. We assessed the impact of a simulation-based procedural skills training course on residents' competence in the performance of critical resuscitation procedures. METHODS: We solicited self-assessments of the knowledge and clinical skills required to perform resuscitation procedures from a cross-sectional multidisciplinary sample of 28 resident study participants. Participants were then exposed to an intensive 8-hour simulation-based training program, and asked to repeat the self-assessment questionnaires on completion of the course, and again 3 months later. We assessed the validity of the self-assessment questionnaire by evaluating participants' skills acquisition through an Objective Structured Clinical Examination station. RESULTS: We found statistically significant improvements in participants' ratings of both knowledge and clinical skills during the 3 self-assessment periods ( p < 0.001). The participants' year of postgraduate training influenced their self assessment of knowledge ( F = 4.91, p< 0.01) and clinical 2,25 skills ( F = 10.89, p< 0.001). At the 3-month follow-up, junior 2,25 level residents showed consistent improvement from their baseline scores, but had regressed from their posttraining measures. Senior-level residents continued to show further increases in their assessments of both clinical skills and knowledge beyond the simulation-based training course. CONCLUSION: Significant improvement in self-assessed theoretical knowledge and procedural skill competence for residents can be achieved through participation in a simulation-based resuscitation course. Gains in perceived competence appear to be stable over time, with senior learners gaining further confidence at the 3-month follow-up. Our findings support the benefits of simulation-based training for residents.