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R A Caplan

Publications and source records attributed to R A Caplan.

34 records · Page 2Linked to original sources
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

Reliability of ratings of anesthesia's contribution to adverse surgical outcomes.

The interrater reliability of physician ratings of anesthesia contribution to adverse outcomes was evaluated. A physician panel reviewed hospital records, anesthesia records, standard data collection forms, and, when available, autopsy reports for 28 patients experiencing severe morbidity or death within 48 hours following anesthesia for surgery. Consensus among reviewers about the contribution of anesthesia to adverse outcomes ranged from 82.1% to 92.9%. Kappa coefficients indicated excellent interrater reliability for the Edwards Scale and rating scale, and good interrater reliability for the percent scale.

Anesthesia↗
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↗
PubMed1990

Nerve injury associated with anesthesia.

The authors examined the American Society of Anesthesiologists Closed Claims Study database to define the role of nerve damage in the overall spectrum of anesthesia-related injury that leads to litigation. Of 1,541 claims reviewed, 227 (15%) were for anesthesia-related nerve injury. Ulnar neuropathy represented one-third of all nerve injuries and was the most frequent nerve injury. Less-frequent sites of nerve injury were the brachial plexus (23%) and the lumbosacral nerve roots (16%). In a large proportion of cases, the exact mechanism of injury was unclear despite evidence of intensive investigation in the claim files. Median payment for nerve damage claims involving disabling injury was $56,000, which was significantly lower than the $225,000 median payment for claims for disabling injury not involving nerve damage (P less than 0.01). The closed claims reviewers judged that the standard of care had been met significantly more often in claims involving nerve damage than in claims not involving nerve damage. The authors conclude that nerve damage is a significant source of anesthesia-related claims but that the exact mechanism of nerve injury is often unclear. In particular, ulnar nerve injuries seemed to occur without identifiable mechanism.

Anesthesia↗
PubMed1989

Standard of care and anesthesia liability.

For the past 3 years, the Committee on Professional Liability of the American Society of Anesthesiologists has been studying records of closed malpractice claims files for anesthesia-related patient injuries. The database of 1004 lawsuits was examined to define the impact of the "standard of care," as judged by a practicing group of anesthesiologists, on the likelihood and amount of financial recovery. We found that payment was made in more than 80% of claims made by patients who were judged to have received substandard anesthetic care. Payment also was made in more than 40% of claims when the anesthesia care was judged to be appropriate. We conclude that in the tort-based system of compensation for anesthesia-related injury, the patient has a high probability of financial recovery for injury caused by substandard care. However, if the anesthesiologist provides appropriate care there is still a greater than 40% chance that payment will be made for the claim of malpractice.

Anesthesia↗
PubMed1989

Transdermal fentanyl for postoperative pain management. A double-blind placebo study.

A double-blind, placebo-controlled, randomized design was used to evaluate the safety and efficacy of transdermal fentanyl citrate for postoperative pain management in 42 healthy adult patients undergoing major shoulder surgery. Transdermal systems rated to deliver fentanyl citrate at a rate of 75 micrograms/h were applied to the skin immediately prior to surgery and worn for 24 hours. Patients in the active group required significantly less morphine than the placebo group during the 24-hour period that systems were in place (0.8 +/- 0.61 vs 1.3 +/- 0.64 mg/h) and for the first 12 hours after removal (0.3 +/- 0.36 vs 0.5 +/- 0.32 mg/h). The incidence of vomiting was more frequent in the active group than in the placebo group (73% vs 30%), and respiratory rate in the active group was lower than in the placebo group during the 13- to 24-hour interval of system application (14 +/- 3 vs 16 +/- 2 breaths per minute). Nevertheless, transdermal fentanyl appears to be safe and effective after orthopedic surgery in healthy adult patients.

Administration, Cutaneous↗
PubMed1989

Role of monitoring devices in prevention of anesthetic mishaps: a closed claims analysis.

Anesthesiologist-reviewers examined 1,175 anesthetic-related closed malpractice claims from 17 professional liability insurance companies. The claims were filed between 1974 and 1988. The reviewers were asked to determine if the negative outcome was preventable by proper use of additional monitoring devices available at the time of the review even if not available at the time the incident occurred, and if so, which devices could have been preventative. In 1,097 cases sufficient information was available to make a judgment regarding preventability of the morbidity or mortality by application of additional monitoring devices. It was determined that 31.5% of the negative outcomes could have been prevented by application of additional monitors. Using the insurance industry's scale of 0 (no injury) to 9 (death), the median severity of injury for incidents deemed preventable was 9 compared with 5 for those deemed not preventable (P less than 0.01, scale detailed in text). The severity of injury scores were the same for preventable mishaps occurring during regional or general anesthesia, suggesting that additional monitoring devices may be equally efficacious in preventing serious negative outcomes during either regional or general anesthesia. The judgements or settlements of the incidents judged preventable by additional monitoring were 11 times more costly (P less than 0.01) than those mishaps not judged preventable. The monitors determined by the reviewers to be most useful in mishap prevention were pulse oximetry plus capnometry. Applied together, these two technologies were considered potentially preventative in 93% of the preventable mishaps.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1989

In-depth analysis of anesthetic mishaps: tools and techniques.

In-depth analysis of an anesthetic mishap requires the acquisition and analysis of a complex body of data. These tasks are facilitated by specific tools and approaches. At the outset, the reviewer should create a registry for documents and seek a factual overview of events. Basic information about case management should be obtained with a structured survey instrument. Critical pieces of information must be explicitly indexed for later examination. Timelines are particularly effective for organizing and displaying key events. The process of data analysis can be expedited by starting with broad concerns and moving to finer distinctions in a stepwise manner. Preparation of a short summary is the first analytic task. Next, the relationships between the injury, the mechanism of injury, and the contributory actions of the caretakers are formally linked as a hypothesis of injury. Finally, each contributory action is examined individually to determine if it represents a deviation from the standard of care. Contradictory information is an expected feature of in-depth analysis. This problem can often be resolved by testing for clinical relevance, identifying obvious inaccuracies, and emphasizing findings from the most reliable sources. Recent work suggests that practicing anesthesiologists can analyze mishaps with a significant degree of interrater reliability. Thus, aggregate data obtained from in-depth analysis may play an increasingly important role in research, risk management, and peer review.

Anesthesiology↗
PubMed1988

Peer reviewer agreement for major anesthetic mishaps.

In a study of peer reviewer agreement for major anesthetic mishaps, 42 anesthesiologists performed a standardized peer review of 48 reports of anesthetic mishaps obtained from a national data base. The peer review group exhibited agreement (P less than 0.0001) for judgments on the appropriateness of clinical care, the presence or absence of human error, and the role of better monitoring in prevention of the mishap. Personal attributes of the reviewers (eg, type of practice, length of time in practice, and previous experience with mishap review) did not appear to influence agreement. The study findings suggest a highly favorable environment for the development of broadly recognized standards of care in anesthesiology.

Anesthesia↗
PubMed1988

Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors.

Fourteen cases of sudden cardiac arrest in healthy patients who received spinal anesthesia were discovered in a preliminary review of 900 closed insurance claims for major anesthetic mishaps. All patients were resuscitated from the intraoperative cardiac arrest, but six suffered such severe neurologic injury that they died in hospital. Of the eight survivors, only one exhibited sufficient neurologic recovery to allow independence in daily self-care. In view of the unexpected nature of the cardiac arrests, as well as the ultimate severity of injury, these cases were analyzed in detail to determine whether there were recurring patterns of management that may have contributed to the occurrence or outcome of these anesthetic mishaps. Two patterns were identified. The first was the intraoperative use of sufficient sedation to produce a comfortable-appearing, sleep-like state in which there was no spontaneous verbalization. Cyanosis frequently heralded the onset of cardiac arrest in patients exhibiting this degree of sedation, suggesting that unappreciated respiratory insufficiency may have played an important role. The second pattern appeared to be an inadequate appreciation of the interaction between sympathetic blockade during high spinal anesthesia and the mechanisms of cardiopulmonary resuscitation. Prompt augmentation of central venous filing through the use of a potent alpha-agonist and positional change might have improved organ perfusion, shortened the duration of cardiac arrest, and lessened the degree of neurologic damage.

Adult↗
PubMed1986

Recognition of an unsuspected phaeochromocytoma during elective coronary artery bypass surgery.

A patient with a longstanding history of mild hypertension undergoing elective coronary artery bypass grafting exhibited extreme and paroxysmal elevations of systemic blood pressure immediately after separation from cardiopulmonary bypass. Conventional antihypertensive therapy (nitroprusside, hydralazine, propranolol) was ineffective, whereas phentolamine infusion produced a decrease in systemic blood pressure. These observations led to the discovery of a predominantly norepinephrine-secreting phaeochromocytoma. This case is noteworthy in that cardiopulmonary bypass may have served as a stimulus for tumour secretion of catecholamine. Possible mechanisms for this effect are discussed.

Adrenal Gland Neoplasms↗
PubMed1986

Interaction of halothane and verapamil in isolated papillary muscle.

The combined depressant effects of verapamil and halothane on myocardial contractility were studied using isolated papillary muscle from the rabbit. Verapamil alone (0.5 microM) significantly decreased peak developed tension (PDT) by 15 +/- 2%, time to peak tension (TPT) by 10 +/- 1%, and maximum rate of increase of tension (+dT/dt) by 5 +/- 1%, but not maximum rate of decrease of tension (-dT/dt). Halothane alone (0.8%) significantly decreased PDT by 56 +/- 2%, TPT by 11 +/- 2%, +dT/dt by 53 +/- 2%, and -dT/dt by 56 +/- 2%. During the exposure period, the combination of verapamil and halothane together produced a simple additive effect (no significant interaction effect by two-way analysis of variance), with PDT decreased by 68 +/- 2%, TPT by 20 +/- 3%, +dT/dt by 62 +/- 2%, and -dT/dt by 65 +/- 2%. The reversibility of halothane-induced depression was also studied. Peak developed tension showed complete reversibility 30 min after discontinuing halothane. In the presence of verapamil, however, the reversibility of halothane-induced depression was not complete, and significant residual depression of PDT (19 +/- 3%) was observed. We conclude that the acute depressant effect of verapamil plus halothane in isolated papillary muscle is additive, but reversibility of halothane-induced depression may be impaired or prolonged in the presence of verapamil.

Animals↗
PubMed1984

Effect of hydralazine on cardiac output and venous admixture in experimental lung injury.

The mechanism by which hydralazine increases venous admixture (QVA/QT) in the setting of lung injury was investigated in a canine model of noncardiogenic pulmonary edema. Permeability pulmonary edema was produced by administration of oleic acid, 0.08 ml/kg given intravenously to 9 mongrel dogs. After stabilization of lung injury, hydralazine was administered intravenously in a loading dose of 1 mg/kg and followed by a constant infusion at 0.05 mg/kg/h. To control for the effect of increased cardiac output (QT) on QVA/QT, a balloon catheter was placed in the inferior vena cava, and stepwise inflation of the balloon was used to impede venous return and maintain QT at predrug levels. Prior to inflation of the balloon catheter, administration of hydralazine produced a 51% decrease in total systemic resistance (TSR) and a 23% decrease in mean arterial pressure (Pa). In contrast, pulmonary vascular resistance (PVR) showed no significant change, and mean pulmonary artery pressure (Ppa) increased 47%. Cardiac output increased from 3.4 +/- 0.3 to 5.5 +/- 0.4 L/min (mean +/- SEM; p less than 0.01) after administration of hydralazine, and QVA/QT increased from 23 +/- 7 to 35 +/- 5% (p less than 0.05). Mean arterial oxygen tension (PaO2) showed no significant change. Inflation of the balloon in the inferior vena cava after hydralazine administration reduced QT to 3.1 +/- 0.4 L/min and QVA/QT to 28 +/- 4%. Neither of these values differed significantly from the prehydralazine levels. Similarly, values for Ppa and PVR after hydralazine administration plus balloon inflation did not differ significantly from predrug levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Differences in threshold for protamine toxicity in isolated atrial and ventricular tissue.

The inotropic and chronotropic effects of protamine sulfate on rabbit myocardium were studied using isolated preparations of atrial and ventricular tissue. Each tissue differed markedly in its susceptibility to depression of peak isometric developed tension. The threshold concentration for depression of tension was 0.022% for left atrium, 0.055% for right atrium, and 0.3% for right ventricular papillary muscle. Tension in the left atrial preparation increased 20% over control at a protamine concentration of 0.02%, but decreased to less than 30% of control at a concentration of 0.022%. Right atrial tissue tension decreased to 48% of control at a protamine concentration of 0.055% and then to 17% of control at a concentration of 0.6%. In papillary muscle, tension decreased to 64% of control at a concentration of 0.3% and then to 9% of control at a concentration of 0.35%. Thus a very steep dose-response curve was observed for each tissue. In the right atrium-sinoatrial node preparation, administration of protamine at concentrations of 0.05-0.06% produced intermittent atrial extrasystoles, but no significant change in overall rate of discharge. The narrow margin of safety of the protamine dose-response curve may provide a partial explanation for the precipitous nature of hypotensive episodes during clinical administration.

Animals↗