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Biomedical subjects

I H Wright

Publications and source records attributed to I H Wright.

16 recordsLinked to original sources

Comparison of bioimpedance versus thermodilution cardiac output during cardiac surgery: evaluation of a second-generation bioimpedance device.

OBJECTIVE: To compare a second-generation thoracic electrical bioimpedance (TEB) hemodynamic monitoring system with the clinically used pulmonary artery catheter thermodilution (TD-PAC) system. DESIGN: Blinded, simultaneous measurements at specified key time points during surgery. SETTING: University teaching hospital cardiac surgical operating rooms. PARTICIPANTS: Forty-seven patients undergoing primary elective coronary artery bypass surgery. INTERVENTIONS: Timed cardiac output measurements by thermodilution and continuous monitoring of bioimpedance were performed. MEASUREMENTS AND MAIN RESULTS: Cardiac index (TEB and TD-PAC) and other hemodynamic parameters were measured at 4 time points: (1) after anesthesia induction, (2) with the mediastinum open, (3) immediately after cardiopulmonary bypass, and (4) at the end of the case. Pearson's correlation and Bland-Altman analysis were carried out. Cardiac index by TEB and TD-PAC had an overall correlation of r = 0.71 (p < 0.0001). The Bland-Altman statistics showed a mean difference of -0.28 L/min/m2 and precision of 0.67 L/min/m2. The best correlation was at time 1, and the lowest correlation was at time 4. Mediastinal opening and cardiopulmonary bypass had little or no effect on the correlation between technologies. CONCLUSION: TEB reporting of cardiac index during coronary artery surgery generally agreed with TD-PAC cardiac index except at the end of the case (time 4).

Adult↗

Statistical modeling to predict elective surgery time. Comparison with a computer scheduling system and surgeon-provided estimates.

BACKGROUND: Accurate estimation of operating times is a prerequisite for the efficient scheduling of the operating suite. The authors, in this study, sought to compare surgeons' time estimates for elective cases with those of commercial scheduling software, and to ascertain whether improvements could be made by regression modeling. METHODS: The study was conducted at the University of Washington Medical Center in three phases. Phase 1 retrospectively reviewed surgeons' time estimates and the scheduling system's estimates throughout 1 yr. In phase 2, data were collected prospectively from participating surgeons by means of a data entry form completed at the time of scheduling elective cases. Data included the procedure code, estimated operating time, estimated case difficulty, and potential factors that might affect the duration. In phase 3, identical data were collected from five selected surgeons by personal interview. RESULTS: In phase 1, 26 of 43 surgeons provided significantly better estimates than did the scheduling system (P < 0.01), and no surgeon was significantly worse, although the absolute errors were large (34% of 157 min average case length). In phase 2, modeling improved the accuracy of the surgeons' estimates by 11.5%, compared with the scheduling system. In phase 3, applying the model from phase 2 improved the accuracy of the surgeons' estimates by 18.2%. CONCLUSIONS: Surgeons provide more accurate time estimates than does the scheduling software as it is used in our institution. Regression modeling effects modest improvements in accuracy. Further improvements would be likely if the hospital information system could provide timely historical data and feedback to the surgeons.

Appointments and Schedules↗

Linking process and outcome of care in a continuous quality improvement program for anesthesia services.

We developed a continuous quality improvement (CQI) program for anesthesia services based on self-reporting of critical incidents and negative outcomes through a dichotomous (yes/no) response on the anesthesia record. Immediate case investigation provides data for systematic peer review of anesthesia management. Trend analysis of the database of critical incidents and negative outcomes identifies opportunities for improvement. The CQI program resulted in the reporting of nearly twice as many problems related to anesthesia management (5% of all anesthetics) as did the checklist it replaced (2.7%). Escalation of patient care (3.2%) and operational inefficiencies (2.2%) were more common than patient injury (1.5% of all anesthetics). Among the 537 cases with anesthesia management problems were 119 human errors and equipment problems (22%). Regional nerve blocks and airway management represented the most common problem areas. Improvement in anesthesia services was made through prompt implementation of strategies for problem prevention devised by the practitioners themselves through peer review, literature review, and clinical investigations.

Anesthesia Department, Hospital↗

Radiation exposure to the hands of orthopaedic surgeons during procedures under fluoroscopic X-ray control.

The hands of the surgeon are most likely to be directly exposed to ionizing radiation during fluoroscopic screening in the orthopaedic theatre. There is however little information available on the level of exposure to radiation during the normal working pattern of individual surgeons. The purpose of this study was to directly measure the radiation exposure to the hands during fluoroscopic screening in a series of consecutive cases over a month in order to establish whether these staff need to be designated classified persons, and if not, whether they need to be routinely monitored. Extremity monitoring was carried out using thermoluminescent dosimeters. The dosimeter was secured to the operating surgeon's dominant index finger. 44 procedures were carried out by nine different surgeons. The total radiation dose received per surgeon ranged from 48-2329 microSv. In 80% of procedures the dose of radiation to the surgeon's hand was less than 100 microSv. The extrapolated annual dose, even for the surgeon with the highest radiation exposure, was well below the annual dose limit for extremities of 500 mSv per year recommended by the International Commission on Radiological Protection, and embodied in the Ionizing Radiations Regulations 1985. Despite the relatively low doses of radiation received by surgeons in this study, occupational exposure to all personnel should be kept to the lowest practicable levels, and a review of procedures, including dose measurements, from time to time is advised.

Fingers↗

Glasgow marathons 1982-1987. A review of medical problems.

The race statistics, whether conditions and incidence of medical problems for the six consecutive years of the Glasgow Marathon are reviewed. The results suggest that the popularity of marathon running is declining but that the competitors are becoming more experienced, seeking medical assistance earlier and, as a result, experiencing fewer and less serious problems at the finish. The effect of weather conditions on the runners' performance is discussed.

First Aid↗

Cardiovascular instability following bolus dose of etomidate.

A patient with alveolar proteinosis developed unexpected cardiovascular instability after broncho-alveolar lavage. He had received two bolus doses of etomidate within an 18-hour period. Serum cortisol concentrations were low and hydrocortisone replacement therapy was necessary to restore arterial pressure. Implications for management of critically ill patients who receive bolus doses of etomidate are discussed.

Anesthesia, Intravenous↗

Changes in anti-endotoxin-IgG antibody and endotoxaemia in three cases of gram-negative septic shock.

Circulating endotoxin levels and IgG antibodies to a range of Gram-negative bacterial lipopolysaccharides (LPS) (endotoxins) of different sizes and structures were measured daily in three cases of septic shock. There was an inverse relationship between endotoxin levels and cross-reactive antibodies to the core glycolipid (CGL) region of lipopolysaccharide. This suggests that antibody to LPS-CGL was initially consumed by a superabundance of endotoxin, and that a resurgence of intrinsic anti-LPS-CGL antibody levels may be associated with a reduction of circulating endotoxin. The implications of these findings for passive antibody therapy of septic shock are discussed.

Adult↗

Critical abdominal sepsis.

Intra-abdominal sepsis is a heterogeneous condition which in its severe forms carries a high mortality. The systemic consequences of established major infection are the result of a complex pathophysiology whose mechanisms are imcompletely understood. It is clear that early appropriate therapy is vital in minimizing effects of intra-abdominal infection and to this end early recognition of sepsis is important. Clinical examination may be unhelpful in difficult cases and special investigations may aid diagnosis; a high index of suspicion is mandatory. Surgery is the mainstay of therapy but may be inadequate and supportive measures are an essential adjunct.

Acute Disease↗

Provision of facilities for secondary transport of seriously ill patients in the United Kingdom.

A survey by questionnaire of 280 hospitals with general intensive care units was carried out to find out what facilities were provided for secondary transport of seriously ill patients in the United Kingdom. Replies were received from 181 units. Extrapolating from the survey data showed that about 10,000 patients were transported each year, although many units transferred only a few patients. An appreciable minority of units reported that facilities for secondary transport were inadequate and many were obliged to send inexperienced medical staff with patients. Almost half of the respondents thought that arrangements for transfer were unsatisfactory, but only a tenth said that they delayed or refused transfer for this reason. This undoubtedly reflects a policy of "making do" despite inadequate resources. We believe that these results support the concept of regional transport services, where each major unit would be adequately equipped and staffed and unnecessary duplication of resources avoided.

Ambulances↗

Postoperative intra-abdominal sepsis.

Postoperative intra-abdominal sepsis carries a high mortality. Diagnosis by clinical examination is often difficult, and imaging techniques may be helpful. Diagnostic laparotomy should be considered early, even in the absence of localizing signs. The use of aggressive surgical techniques may improve prognosis. The timing of surgical intervention is as important as the technique. Early diagnosis and treatment is particularly crucial in critically ill patients.

Abdomen↗

Acute poisoning with gold cyanide.

A case of deliberate ingestion of an electroplating solution containing gold cyanide is described. Despite the use of an antidote, and supportive treatment for cyanide poisoning, the patient died after 13 hours. Sublethal cyanide and high red blood cell gold levels suggest acute gold toxicity as the most likely cause of death. Evidence for this is discussed and recommendations are made for the treatment of cyanide poisoning.

Acute Disease↗

Unusual indications for liver transplantation.

This paper is an attempt to present some of the unusual indications for OLTx that are occasionally seen at transplant centers. It is not an all-encompassing treatise but rather an attempt to present the more usual of the unusual indications for OLTx. As such, it is a framework to which readers could add any we do not mention as and when they are encountered in their own practice.

Cystic Fibrosis↗