James M. Blum

Electronic reminders improve procedure documentation compliance and professional fee reimbursement.

BACKGROUND:Medicolegal, clinical, and reimbursement needs warrant complete and accurate documentation. We sought to identify and improve our compliance rate for the documentation of arterial catheterization in the perioperative setting. METHODS:We first reviewed 12 mo of electronic anesthesia records to establish a baseline compliance rate for arterial catheter documentation. Residents and Certified Registered Nurse Anesthetists were randomly assigned to a control group and experimental group. When surgical incision and anesthesia end were documented in the electronic record keeper, a reminder routine checked for an invasive arterial blood pressure tracing. If a case used an arterial catheter, but no procedure note was observed, the resident or Certified Registered Nurse Anesthetist assigned to the case was sent an automated alphanumeric pager and e-mail reminder. Providers in the control group received no pager or e-mail message. After 2 mo, all staff received the reminders. RESULTS:A baseline compliance rate of 80% was observed (1963 of 2459 catheters documented). During the 2-mo study period, providers in the control group documented 152 of 202 (75%) arterial catheters, and the experimental group documented 177 of 201 (88%) arterial lines (P < 0.001). After all staff began receiving reminders, 309 of 314 arterial lines were documented in a subsequent 2 mo period (98%). Extrapolating this compliance rate to 12 mo of expected arterial catheter placement would result in an annual incremental

Preoperative and intraoperative predictors of postoperative acute respiratory distress syndrome in a general surgical population.

40,500 of professional fee reimbursement. CONCLUSIONS:The complexity of the tertiary care process results in documentation deficiencies. Inexpensive automated reminders can drastically improve compliance without the need for complicated negative or positive feedback.

Predicting Risk of Postoperative Lung Injury in High-risk Surgical Patients: A Multicenter Cohort Study

Background:Acute respiratory distress syndrome (ARDS) is a devastating condition with an estimated mortality exceeding 30%. There are data suggesting risk factors for ARDS development in high-risk populations, but few data are available in lower incidence populations. Using risk-matched analysis and a combination of clinical and research data sets, we determined the incidence and risk factors for the development of ARDS in this general surgical population. Methods:We conducted a review of common adult surgical procedures completed between June 1, 2004 and May 31, 2009 using an anesthesia information system. This data set was merged with an ARDS registry and an institutional death registry. Preoperative variables were subjected to multivariate analysis. Matching and multivariate regression was used to determine intraoperative factors associated with ARDS development. Results:In total, 50,367 separate patient admissions were identified, and 93 (0.2%) of these patients developed ARDS. Preoperative risk factors for ARDS development included American Society of Anesthesiologist status 3–5 (odds ratio [OR] 18.96), emergent surgery (OR 9.34), renal failure (OR 2.19), chronic obstructive pulmonary disease (OR 2.16), number of anesthetics during the admission (OR 1.37), and male sex (OR 1.65). After matching, intraoperative risk factors included drive pressure (OR 1.17), fraction inspired oxygen (OR 1.02), crystalloid administration in liters (1.43), and erythrocyte transfusion (OR 5.36). Conclusions:ARDS is a rare condition postoperatively in the general surgical population and is exceptionally uncommon in low American Society of Anesthesiologists status patients undergoing scheduled surgery. Analysis after matching suggests that ARDS development is associated with median drive pressure, fraction inspired oxygen, crystalloid volume, and transfusion.

A Description of Intraoperative Ventilator Management in Patients with Acute Lung Injury and the Use of Lung Protective Ventilation Strategies

Background: Acute respiratory distress syndrome (ARDS) remains a serious postoperative complication. Although ARDS prevention is a priority, the inability to identify patients at risk for ARDS remains a barrier to progress. The authors tested and refined the previously reported surgical lung injury prediction (SLIP) model in a multicenter cohort of at-risk surgical patients. Methods: This is a secondary analysis of a multicenter, prospective cohort investigation evaluating high-risk patients undergoing surgery. Preoperative ARDS risk factors and risk modifiers were evaluated for inclusion in a parsimonious risk-prediction model. Multiple imputation and domain analysis were used to facilitate development of a refined model, designated SLIP-2. Area under the receiver operating characteristic curve and the Hosmer–Lemeshow goodness-of-fit test were used to assess model performance. Results: Among 1,562 at-risk patients, ARDS developed in 117 (7.5%). Nine independent predictors of ARDS were identified: sepsis, high-risk aortic vascular surgery, high-risk cardiac surgery, emergency surgery, cirrhosis, admission location other than home, increased respiratory rate (20 to 29 and ≥30 breaths/min), FIO2 greater than 35%, and SpO2 less than 95%. The original SLIP score performed poorly in this heterogeneous cohort with baseline risk factors for ARDS (area under the receiver operating characteristic curve [95% CI], 0.56 [0.50 to 0.62]). In contrast, SLIP-2 score performed well (area under the receiver operating characteristic curve [95% CI], 0.84 [0.81 to 0.88]). Internal validation indicated similar discrimination, with an area under the receiver operating characteristic curve of 0.84. Conclusions: In this multicenter cohort of patients at risk for ARDS, the SLIP-2 score outperformed the original SLIP score. If validated in an independent sample, this tool may help identify surgical patients at high risk for ARDS.

Controlling for cybersecurity risks of medical device software

Background:The incidence of acute lung injury (ALI) in hypoxic patients undergoing surgery is currently unknown. Previous studies have identified lung protective ventilation strategies that are beneficial in the treatment of ALI. The authors sought to determine the incidence and examine the use of lung protective ventilation strategies in patients receiving anesthetics with a known history of ALI. Methods:The ventilation parameters that were used in all patients were reviewed, with an average preoperative Paco2/Fio2 ratio of ≤ 300 between January 1, 2005 and July 1, 2009. This dataset was then merged with a dataset of patients screened for ALI. The median tidal volume, positive end-expiratory pressure, peak inspiratory pressures, fraction inhaled oxygen, oxygen saturation, and tidal volumes were compared between groups. Results:A total of 1,286 patients met criteria for inclusion; 242 had a diagnosis of ALI preoperatively. Comparison of patients with ALI versus those without ALI found statistically yet clinically insignificant differences between the ventilation strategies between the groups in peak inspiratory pressures and positive end-expiratory pressure but no other category. The tidal volumes in cc/kg predicted body weight were approximately 8.7 in both groups. Peak inspiratory pressures were found to be 27.87 cm H2O on average in the non-ALI group and 29.2 in the ALI group. Conclusion:Similar ventilation strategies are used between patients with ALI and those without ALI. These findings suggest that anesthesiologists are not using lung protective ventilation strategies when ventilating patients with low Paco2/Fio2 ratios and ALI, and instead are treating hypoxia and ALI with higher concentrations of oxygen and peak pressures.

A Description of Intraoperative Ventilator Management and Ventilation Strategies in Hypoxic Patients

Medical device hacking is a red herring. But the flaws are real.

The most influential articles in critical care medicine

BACKGROUND: Hypoxia is a common finding in the anesthetized patient. Although there are a variety of methods to address hypoxia, it is not well documented what strategies are used by anesthesiologists when faced with a hypoxic patient. Studies have identified that lung protective ventilation strategies have beneficial effects in both oxygenation and mortality in acute respiratory distress syndrome. We sought to describe the ventilation strategies in anesthetized patients with varying degrees of hypoxemia as defined by the PaO2 to fraction of inspired oxygen (FIO2) (P/F) ratio. METHODS: We conducted a review of all operations performed between January 1, 2005, and July 31, 2009, using a general anesthetic, excluding cardiac and thoracic procedures, to assess the ventilation settings that were used in patients with different P/F ratios. Patients older than 18 years who received a general anesthetic were included. Four cohorts of arterial blood gases (ABGs) were identified with P/F >300, 300 ≥ P/F > 200, 200 ≥ P/F > 100, 100 ≥ P/F. Using the standard predicted body weight (PBW) equation, we calculated the milliliters per kilogram (mL/kg PBW) with which the patients lungs were being ventilated. Positive end-expiratory pressure (PEEP), peak inspiratory pressures (PIPs), FIO2, oxygen saturation (SaO2), and tidal volume in mL/kg PBW were compared. RESULTS: A total of 28,706 ABGs from 11,445 operative cases met criteria for inclusion. There were 19,679 ABGs from the P/F >300 group, 5364 ABGs from the 300 ≥ P/F > 200 group, 3101 ABGs from the 200 ≥ P/F > 100 group, and 562 ABGs from the 100 ≥ P/F group identified. A comparison of ventilation strategies found statistical significance but clinically irrelevant differences. Tidal volumes ranged between 8.64 and 9.16 and the average PEEP varied from 2.5 to 5.5 cm H2O. There were substantial differences in the average FIO2 and PIP among the groups, 59% to 91% and 22 to 29 cm H2O, respectively. CONCLUSION: Similar ventilation strategies in mL/kg PBW and PEEP were used among patients regardless of P/F ratio. The results of this study suggest that anesthesiologists, in general, are treating hypoxemia with higher FIO2 and PIP. The average FIO2 and PIP were significantly escalated depending on the P/F ratio.

Improvement in the Quality of Randomized Controlled Trials Among General Anesthesiology Journals 2000 to 2006: A 6-Year Follow-Up

Abstract Purpose The study aimed to examine query strategies that would provide an exhaustive search method to retrieve the most referenced articles within specific categories of critical care. Material and Methods A comprehensive list of the most cited critical care medicine articles was generated by searching the Science Citation Index Expanded data set using general critical care terms keywords such as “critical care,” critical care journal titles, and keywords for subsubjects of critical care. Results The final database included 1187 articles published between 1905 and 2006. The most cited article was referenced 4909 times. The most productive search term was intensive care. However, this term only retrieved 25% of the top 100 articles. Furthermore, 662 of the top 1000 articles could not be found using any of the basic critical care search terms. Sepsis, acute lung injury, and mechanical ventilation were the most common areas of focus for the articles retrieved. Conclusion Retrieving frequently cited, influential articles in critical care requires using multiple search terms and manuscript sources. Periodic compilations of most cited articles may be useful for critical care practitioners and researches to keep abreast of important information.

Specificity improvement for network distributed physiologic alarms based on a simple deterministic reactive intelligent agent in the critical care environment.

BACKGROUND: We previously assessed all randomized controlled trials (RCTs) from four anesthesiology journals from January 2000 to December 2000. We identified key areas for improvement in the study protocol design and implementation and in data analyses. This study was repeated for the year 2006 to determine if improvements have occurred during the 6-yr interval. METHODS: All RCTs published in 2006 in four anesthesiology journals (Anesthesiology, Anesthesia & Analgesia, Anaesthesia, and Canadian Journal of Anesthesia) were retrieved using a MEDLINE search. Of 2164 articles published in 2006, 200 papers met these search criteria and were considered valid for analysis. We completed a 14-item, validated assessment tool used in our previous study to determine a quality score for each article. Four clinical reviewers each assessed 50 articles, and one reviewer assessed all 200 articles. Points were assigned by consensus. Scores were weighted and compared with the results from the year 2000. RESULTS: Quality scores improved from the year 2000 to 2006, from a mean overall quality score of 44% (95% CI = 42, 46) to a mean score of 58% (95% CI = 55, 60). Specific areas of study, quality assessment demonstrating improvement, included sample size estimates (52% vs 86%, P < 0.0001), major end-points (44% vs 99%, P < 0.0001), and discussion of side effects (68% vs 82%, P = 0.0019). Low quality scores remained for randomization blinding (4% vs 19% P < 0.0001), observer blinding to continuing studies (1% vs 5% P = 0.116), and post-β estimates in trials with negative outcomes (16% vs 18%, P < 0.87). CONCLUSIONS: There appears to have been a general improvement in the overall quality of RCT reporting among the major anesthesiology journals from the year 2000 to 2006. However, many articles could be improved with respect to randomization blinding, observer blinding to continuing study results (i.e., no unplanned interim data analysis), and a full discussion of Type II error in negative trials. Responsibility to improve the quality of the anesthesiology literature rests with investigators to design, implement and report high quality RCTs, and with peer reviewers and journal editors to set the standard for manuscript reporting. Periodic reassessments of the literature can serve to improve and maintain the quality of clinical trials reporting.

Automated Alerting and Recommendations for the Management of Patients with Preexisting Hypoxia and Potential Acute Lung Injury: A Pilot Study

Automated physiologic alarms are available in most commercial physiologic monitors. However, due to the variability of data coming from the physiologic sensors describing the state of patients, false positive alarms frequently occur. Each alarm requires review and documentation, which consumes clinicians’ time, may reduce patient safety through ‘alert fatigue’ and makes automated physician paging infeasible. To address these issues a computerized architecture based on simple reactive intelligent agent technology has been developed and implemented in a live critical care unit to facilitate the investigation of deterministic algorithms for the improvement of the sensitivity and specificity of physiologic alarms. The initial proposed algorithm uses a combination of median filters and production rules to make decisions about what alarms to generate. The alarms are used to classify the state of patients and alerts can be easily viewed and distributed using standard network, SQL database and Internet technologies. To evaluate the proposed algorithm, a 28 day study was conducted in the University of Michigan Medical Center’s 14 bed Cardiothoracic Intensive Care Unit. Alarms generated by patient monitors, the intelligent agent and alerts documented on patient flow sheets were compared. Significant improvements in the specificity of the physiologic alarms based on systolic and mean blood pressure was found on average to be 99% and 88% respectively. Even through significant improvements were noted based on this algorithm much work still needs to be done to ensure the sensitivity of alarms and methods to handle spurious sensor data due to patient or sensor movement and other influences.