Biomedical subjects

K L Posner

Publications and source records attributed to K L Posner.

24 records · Page 2Linked to original sources

PubMed1991

Effect of outcome on physician judgments of appropriateness of care.

Is a permanent injury more likely to elicit a rating of inappropriate care than a temporary injury? To explore this question, we asked 112 practicing anesthesiologists to judge the appropriateness of care in 21 cases involving adverse anesthetic outcomes. The original outcome in each case was classified as either temporary or permanent. The authors then generated a matching alternate case identical to the original in every respect except that a plausible outcome of opposite severity was substituted. The original and alternate cases were randomly divided into two sets and assigned to reviewers who were blind to the intent of the study. The reviewers were asked to rate independently the care in each case as appropriate, less than appropriate, or impossible to judge, based on their personal (implicit) judgment of reasonable and prudent practice. A significant inverse relationship between severity of outcome and judgments of appropriateness of care was observed in 15 (71%) of the 21 matched pairs of cases. Overall, the proportion of ratings for appropriate care decreased by 31 percentage points when the outcome was changed from temporary to permanent and increased by 28 percentage points when the outcome was changed from permanent to temporary. We conclude that knowledge of the severity of outcome can influence a reviewer's judgment of the appropriateness of care.

Anesthesia↗

PubMed1991

A prospective study of intraoperative pulse oximetry failure.

Since pulse oximetry is now an ASA standard for intraoperative monitoring, we sought to determine the intraoperative failure rate for this device. We prospectively evaluated the intraoperative failure rate of our pulse oximeters at the four University of Washington Hospitals (University of Washington Medical Center, Veterans Affairs Medical Center [VAMC], Children's Hospital and Medical Center, and Harborview Medical Center [HMC]) recorded from April 1989 to August 1989. We defined failure as the inability to obtain any oximetry reading for a cumulative period of more than 30 minutes during any anesthetic procedure after all equipment malfunctions had been eliminated. Our puse oximeters failed in 124 of 11,046 cases studied; this is a failure rate of 1.12%, which ranged from 0.56% at HMC to 4.24% at VAMC. The failure rate at VAMC (4.24%) was significantly higher than the other hospitals (p less than 0.001). Those cases associated with the pulse oximeter failure had the following characteristics: (1) an ASA status of 3 or higher, (2) lengthy operations, and (3) elderly patients. When the device did fail in a patient, it did not function for 32% of the mean anesthesia time. We conclude that the intraoperative use of the pulse oximetry can provide information about blood oxygen saturation in most patients. However, in approximately 1% of the patients we studied in the operating room, mechanically functioning pulse oximeters failed to provide readings of blood oxygen saturations during routine operative use.

Equipment Failure↗

PubMed1991

A disposable end-tidal CO2 detector to verify endotracheal intubation.

STUDY OBJECTIVE: We compared the performance of the Fenem FEF end-tidal CO2 detector with the TRIMED capnometer to verify endotracheal intubation. DESIGN: The FEF indicates the presence of CO2 by the color change of a chemically treated indicator; the TRIMED uses infrared technology. Both devices were used during 60 intubations. SETTING: Intubations during in-hospital emergency situations outside of the operating room were studied. TYPE OF PARTICIPANTS: Adult patients undergoing intubation for respiratory failure, CPR, and other airway protection situations were enrolled in the study. INTERVENTIONS: The TRIMED monitor and FEF detector were placed in series between the manual resuscitator and the patient's endotracheal tube adapter after endotracheal tube placement. MEASUREMENTS AND MAIN RESULTS: We defined the acceptable criterion for detection of CO2 as production of a positive signal within six manual resuscitator bag breaths. The TRIMED met this criterion in 58 of 60 patients (sensitivity, 0.97) and the FEF met this criterion in 59 of 60 patients (sensitivity, 0.98). A paired t test showed no statistically significant difference in performance between the two devices. In five of nine cases of intubation during CPR, the color change of the FEF was described as "subtle." In one CPR case, a positive signal was not obtained by either device. CONCLUSION: We conclude that the performance of the FEF CO2 detector is equal to that of the TRIMED monitor for verification of endotracheal intubation in nonCPR situations. Interpretation of FEF color changes during CPR should be approached with caution until further studies using the FEF during CPR are completed.

Adult↗

PubMed1991

Adverse respiratory events infrequently leading to malpractice suits. A closed claims analysis.

Adverse outcomes associated with respiratory events are the single largest class of injury in the American Society of Anesthesiologists Closed Claims Project (762 of the 2,046 cases, 37%). Inadequate ventilation, esophageal intubation, and difficult tracheal intubation are the most common mechanisms of respiratory-related adverse outcomes. An analysis of closed claims data regarding these mechanisms has been reported previously. This report is concerned with 300 claims for five other less common but important categories of respiratory-related adverse outcomes in which recurrent themes of management error or patterns of injury could be identified: airway trauma, pneumothorax, airway obstruction, aspiration, and bronchospasm. Airway trauma (97 claims, 5% of the database) was associated with difficult intubation in 41 (42%) of the cases and the most frequent sites of injury were the larynx, pharynx, and esophagus. Pneumothorax (67 cases, 3% of the database) was usually either needle-related (block or central vascular catheter placement) or airway management-related (instrumentation or barotrauma). Airway obstruction (56 claims, 3% of the database) occurred in the upper airway in 39 (70%) of the cases. Aspiration (56 claims, 3% of the database) usually occurred during general anesthesia, either during induction prior to tracheal intubation or during maintenance of anesthesia delivered via mask. Bronchospasm (40 claims, 2% of the database) tended to occur during induction of general anesthesia in patients with a history of asthma or chronic obstructive pulmonary disease and/or smoking. The incidence of severe injury (brain damage and death) among these cases in the five categories was 47% overall, ranging from 12% in airway trauma claims to nearly 90% in claims for airway obstruction and bronchospasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗

PubMed1990

Measuring interrater reliability among multiple raters: an example of methods for nominal data.

This paper reviews and critiques various approaches to the measurement of reliability among multiple raters in the case of nominal data. We consider measurement of the overall reliability of a group of raters (using kappa-like statistics) as well as the reliability of individual raters with respect to a group. We introduce modifications of previously published estimators appropriate for measurement of reliability in the case of stratified sampling frames and we interpret these measures in view of standard errors computed using the jackknife. Analyses of a set of 48 anaesthesia case histories in which 42 anaesthesiologists independently rated the appropriateness of care on a nominal scale serve as an example.

Reproducibility of Results↗

PubMed1990

Adverse respiratory events in anesthesia: a closed claims analysis.

Adverse outcomes associated with respiratory events constitute the single largest class of injury in the American Society of Anesthesiology Closed Claims Study (522 of 1541 cases; 34%). Death or brain damage occurred in 85% of cases. The median cost of settlement or jury award was +200,000. Most outcomes (72%) were considered preventable with better monitoring. Three mechanisms of injury accounted for three-fourths of the adverse respiratory events: inadequate ventilation (196; 38%), esophageal intubation (94; 18%), and difficult tracheal intubation (87; 17%). Inadequate ventilation was used to describe claims in which it was evident that insufficient gas exchange had produced the adverse outcome, but it was not possible to identify the exact cause. This group was characterized by the highest proportion of cases in which care was considered substandard (90%). The esophageal intubation group was notable for a recurring diagnostic failure: in 48% of cases where auscultation of breath sounds was performed and documented, this test led to the erroneous conclusion that the endotracheal tube was correctly located in the trachea. Claims for difficult tracheal intubation were distinguished by a comparatively small proportion of cases (36%) in which the outcome was considered preventable with better monitoring. A better understanding of respiratory risks may require investigative protocols that initiate data collection immediately upon the recognition of a critical incident or adverse outcome.

Adolescent↗