Management of supraglottic cancer: selected endoscopic laser resection and postoperative irradiation.
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Carcinoma, Squamous Cell↗
Biomedical subjects
J K Hayes
Publications and source records attributed to J K Hayes.
Monitoring normal and aberrant electrocardiographic activity from an endotracheal tube: comparison of the surface, esophageal, and tracheal electrocardiograms.
INTRODUCTION: We designed an endotracheal (ET) tube with orthogonally spaced ECG cuff electrodes. This ET tube was evaluated in dogs and sheep to determine (1) whether ECGs recorded from our tube were sufficient to make accurate clinical decisions concerning heart rate and rhythm; and (2) whether metallic cuff electrodes in direct contact with the trachea could induce mucosal burn injury during episodes of defibrillation. METHODS: Using experimental animals, we obtained ECGs from their tracheae and compared our findings with ECGs obtained from surface and esophageal electrodes. The electrical activity of the heart was modified by increasing the depth of anesthesia, occluding the left coronary artery, and administering beta-adrenergic drugs. Before the dogs were euthanized, they were subjected to episodes of transthoracic and intrathoracic defibrillation at energy levels of 200 to 400 J. A postmortem pathological examination of the trachea was performed to determine the incidence of mucosal burn injury. RESULTS: Tracheal electrocardiography provided valid information on heart-rate monitoring and certain morphology profiles. The R-R, PR, QRS, and QT intervals measured from the trachea had a correlation of 1.0, 0.96, 0.83, and 0.98, respectively, when compared with the same intervals obtained from surface electrodes. Two tracheae subjected to intrathoracic defibrillation at > 300 J revealed evidence of minor burn injury. Some localized epithelium loss was displayed in all tracheae; we attributed this to tracheal intubation. CONCLUSION: Tracheal electrocardiography may be useful in trauma patients who require intubation where injury precludes placement of chest ECG electrodes.
Animals↗
Computed tomography treatment planning in IR-192 brachytherapy in the head and neck.
Brachytherapy dose prescription and treatment planning lag behind the state-of-the-art for external beam therapy. As altered fractionation of external beam therapy improves patient outcome in head and neck cancer, there will be an increased need to compare the two radiotherapy techniques. Currently, implant techniques and dose prescription documentation are not uniform, dose prescription to a target volume is subjective, and implant quality is poorly understood and not routinely assessed. All contribute to a lack of scientifically rigorous brachytherapy clinical trials. Studies designed to combine tumor imaging and dosimetry data are important in the evolution of brachytherapy treatment planning. Head and neck implants, which often require nonparallel, arching, or looping source carriers for all but small tumors in order to encompass the target volume adequately, were used to evaluate the clinical utility and feasibility of computed tomography as a treatment planning tool in brachytherapy. Following placement of plastic afterloading tubes under general anesthesia, orthogonal radiographs with dummy sources in the afterloading tubes are obtained as customary for source localization. With the patient in the same position, axial CT scans are obtained with the dummy seeds still in place for treatment planning. The implant physician, using data from the pre-treatment diagnostic CT scan, outlines target areas on sequential images creating a 3-dimensional target volume. By superimposing anatomic data with isodose curves one can objectively define implant parameters important in clinical trials analysis. These include minimum target absorbed dose, implant uniformity, and treatment to target volume ratio. The results of the first 10 patients are presented and implications of these data regarding the analysis of implant technique, implant quality, and implant optimization are discussed. The technique as performed is laborious but practicable in the clinical research setting of head and neck implant. Further research efforts should improve, simplify, and objectify brachytherapy and hasten the time when rigorous multi-institutional brachytherapy trials will be reality.
Adult↗
Comparison of tidal ventilation and high-frequency jet ventilation before and after cardiopulmonary bypass in dogs using two-dimensional transesophageal echocardiography.
This study compared the use of high-frequency jet ventilation (HFJV) and tidal ventilation (TV) in a group of dogs with induced global myocardial ischemia before and after cardiopulmonary bypass. Transesophageal echocardiography was used to determine whether HFJV with its lower airway pressures could improve cardiac performance. The surgical procedure was separated into four study periods: closed chest before bypass, open chest before bypass, open chest after bypass, and closed chest after bypass. During each of these study periods, the dogs were randomly ventilated with alternate periods of TV and HFJV to maintain the PaCO2 at 34.3 +/- 3.3 mm Hg (mean +/- SEM). Cardiac output, stroke volume, systemic mean blood pressure, left ventricular ejection fraction, left ventricular end-diastolic volume, left ventricular dP/dt, left ventricular stroke work, and expiratory volumetric flows were higher during HFJV, whereas airway pressures and pulmonary vascular resistance were lower. Increases in cardiac output and stroke volume during HFJV were due to a combination of improved left ventricular contractility indicated by increased LV dP/dt and increased left ventricular end-diastolic volume accompanying decreased airway pressures. These data indicate that HFJV with its lower airway pressure is associated with significantly less impairment of cardiovascular function than TV in dogs with induced global myocardial ischemia.
Animals↗
Carotid thrombosis following neck irradiation.
Therapeutic irradiation may accelerate atherosclerosis, increasing the risk of vascular stenosis or occlusion several to many years following radiation. However, intimal damage following irradiation may result earlier in thrombosis without stenosis. This report discusses three cases of carotid occlusion that occurred within 3 years of moderate dose irradiation. Angiographic studies showed that occlusion occurred in the absence of atherosclerotic stenosis. A review of the literature supports the conclusion that people who receive neck irradiation are at risk not only for the delayed development of diffuse atherosclerosis but also for thrombotic occlusion within months to several years. We suggest that patients who develop neurological symptoms or signs following neck irradiation, regardless of age, dose of radiation, or interval since radiation, should be evaluated for carotid or vertebral artery disease.
Adult↗
Definitive radiation therapy in bile duct carcinoma.
Between 1980 and 1985, 24 patients with primary adenocarcinoma of the bile duct were treated with various combinations of surgery, biliary intubation, external irradiation, and transcatheter brachytherapy. Seventy-five percent of tumors were in the proximal bile ducts. Ten patients received no or only palliative radiation, Group 1, whereas 14 patients received definitive courses of radiation (4 by external beam irradiation, 2 by transcatheter irradiation, and 8 by both modalities), Group 2. Survival in Group 1 and Group 2 was significantly different (p less than 0.005) with median survivals of 2.0 and 12.8 months, respectively. This result may be in part due to differences in treatment and in part due to selection bias because the series is small, uncontrolled, and retrospective. Median survival of the 8 patients treated with combined modalities was 13.2 months (range 7.4-30.3) with 4 patients alive 8.7 to 16.2 months, 3 without cholangiographic evidence of disease. Complications of therapy were common, including bacterial sepsis (58%), cholangitis (38%), gastrointestinal bleeding (46%), intra or extrahepatic abscesses (33%), and recurrent biliary obstruction (25%). Cholangitis, hemorrhage, abscesses, and ulcers appeared more frequently in definitively treated patients, whereas recurrent biliary obstruction was absent in this group and frequent in Group 1. Differences in complication rates between groups were not statistically significant. Early diagnosis and management usually reversed a downhill clinical course in patients with abscess and hemorrhage. Both surgical and percutaneous techniques of biliary decompression, the usual initial form of therapy in bile duct cancer, are associated with frequent and serious complications. Although many of our complications may have derived from biliary decompression, it is possible that definitive treatment may have increased the frequency of serious complications.
Adenoma, Bile Duct↗
Candidate products of avian myeloblastosis virus oncogene region produced by in vitro translation of genomic RNA.
Avian myeloblastosis virus (AMV) genomic RNA was translated in vitro to identify the AMV transforming gene (myb) product(s). Full-length RNA yielded, in addition to the expected Pr76gag, a gag-related product of 92,000 daltons which did not appear to be a gag-oncogene fusion protein. Subgenomic AMV RNA in vitro translation, nonstructural products (specific for AMV) were of 54,000, 49,000 and 34,000 daltons. Based on their sizes and similar peptide maps for the smaller two proteins, it is proposed that they derive from the myb region of AMV.
Avian Leukosis Virus↗
Uptake of enflurane: a study of the variability between patients.
Variability in the uptake of enflurane has been studied using a computer-controlled "overpressure" induction technique in 23 paediatric patients. The administration of enflurane was feedback-controlled and its uptake measured using a closed anaesthesia delivery system with the end-tidal concentration held constant at 2.0%. The standard deviation in uptake was greater than 28% of the average uptake during the first 60 min of enflurane anaesthesia. The uptake at 60 min ranged from 5.7 to 16.2 ml min-1 m-2. The variability in enflurane uptake between patients was best minimized by normalizing the patient's uptake according to body surface area. Although the average total volume of enflurane calculated according to a model compared well with the average total volume given in our study, the variation in uptake between patients indicated that a single model cannot be used to deliver anaesthesia to a varied patient population. The system described in this paper demonstrates the feasibility of using feedback control of fresh gas delivery for the automatic control of an "overpressure" induction technique.
Adolescent↗
Monitoring anesthetic vapor concentrations using a piezoelectric detector: evaluation of the Engstrom EMMA.
The Engstrom anesthetic gas analyzer (EMMA) was evaluated to determine the reproducibility, response time, gas interference, water vapor dependence, and sensitivity. The analyzer also was evaluated clinically in 20 children undergoing orthopedic surgery. Difference between the analyzer output and anesthetic gas standard (reproducibility) ranged from 0.013 +/- 0.008 vol % to 0.018 +/- 0.018 vol %. Response times decreased from 710 ms at 5 l X min-1 to 149 ms at 30 l X min-1. Nitrous oxide caused an offset of +0.11 +/- 0.007 vol %. Water vapor caused positive offsets of 0.25 +/- 0.044 vol %, 0.51 +/- 0.027 vol %, and 0.80 +/- 0.037 vol % at 25 degrees C, 30 degrees C, and 34 degrees C, respectively. The analyzer reproducibly measured dry gas concentrations, but compensation had to be made for water vapor when measuring wet gases. The analyzer's usefulness for end-tidal monitoring was questioned because of its slow response time and its sensitivity to water vapor.
Anesthesiology↗
Feedback control of enflurane delivery in dogs--inspired compared to end-tidal control.
A technique was studied for the rapid induction of anesthesia in a closed rebreathing circuit using feedback control of end-tidal enflurane concentration. This technique was compared to anesthetic induction using a constant inspired concentration. In one group of seven dogs, end-tidal enflurane concentration was maintained at 2.0%. Electronic feedback control automatically decreased the inspired concentration from a maximum of 3.7% to 2.1% during a 4-hr period. In the second group of seven dogs, the inspired enflurane concentration was 2.0% throughout the study. There was no statistically significant difference between the two groups with regard to enflurane uptake, heart rate, blood pressure, or cardiac output. Enflurane uptake was higher in the first group only during the first 6 min after induction. The induction technique that used feedback control to automatically adjust the inspired enflurane concentration appeared to have no adverse cardiovascular effects beyond those present during an induction using a constant inspired concentration.
Anesthesia, Inhalation↗
Continuous monitoring of serum ionized calcium in the dog during sodium citrate infusion using an extracorporeal blood shunt.
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Animals↗
Computer-controlled anesthesia delivery system.
A prototype Computer-Controlled Anesthesia Delivery System (CCADS) has been developed. The CCADS uses proportional, integral, and derivative (PID) software algorithms to control the delivery of oxygen, anesthetic agent,and nitrous-oxide (N2O) via the computer feedback control of precision mass-flow controller devices. The CCADS was evaluated in a group of seven dogs during 4 hours of closed-circuit enflurane N2O anesthesia. Throughout the 4-hour monitoring period, the CCADS maintained the animals' inspired oxygen concentration (FIO2), end-tidal enflurane concentration, and breathing circuit volume to within +/- 0.20, +/- 0.10 volume %, and +/- 30 ml/min (+/- 1 SD), respectively, of the desired values. The interactive software allowed selective graphic display of the 10-breath averaged data parameters, or modification of FIO2, end-tidal enflurane concentration, and breathing circuit volume, whenever animal re-evaluation during an anesthesia procedure was necessary.
Anesthesia, Inhalation↗