Cardiopulmonary responses to exercise in children with activity sensing rate responsive ventricular pacemakers

The physiological benefits of activity sensing rate responsive ventricular pacing (VVIR) over fixed rate pacing (VVI) were investigated in 14 children during incremental cycle exercise. Based on their heart rhythm response during exercise, children were divided into two groups. Group I patients (13 +/- 4 years) remained in a paced-only rhythm when exercised. Group II patients (16 +/- 7 years) were paced at rest but converted to sinus rhythm with exercise. In Group I patients, the significant physiological benefits of VVIR over VVI pacing were evidenced by a 51% increase in peak heart rate (HRmax) and a 16% increase in exercise duration and maximum oxygen uptake (VO2max). Additionally, a 27% reduction in peak oxygen pulse (O2Pmax) was found, reflecting a similar decrease in stroke volume. The cardiorespiratory responses of Group I and II patients were compared in terms of percent of predicted normal values. Although Group I patients in the VVIR mode attained a better exercise performance than in the VVI mode and a normal O2Pmax (108% pred), their HRmax (62% pred) and VO2max (70% pred) fell far below normal values. In comparison, Group II patients, who went into sinus rhythm, achieved normal values for HRmax (84% pred), VO2max (90% pred), and O2Pmax (97% pred). The higher pacing rates attained by Group I patients in the VVIR mode may have allowed them to reach not only a higher cardiac output but also a more normal stroke volume at peak exercise than in the VVI mode.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic closure and the spread of uncertainty

When a child is diagnosed with a life-threatening, chronic illness, the taken-for-granted world of the child's parents is destroyed. From that moment on, they must learn to manage life under very uncertain conditions. The findings reported here are from a more comprehensive grounded theory study that sought a plausible explanation for parental behavior under conditions of sustained uncertainty. This report describes the emergence of uncertainty as a multidimensional concept that permeates every aspect of family life following the diagnostic announcement. The noncategorical nature of the dimensions of uncertainty found in all life-threatening, chronic childhood illnesses provides a strong argument for preparing nurses in specialties that are conceptually, rather than medically, based.

Nocardiosis after corticosteroid therapy for malignant thymoma

BACKGROUND

Nocardia asteroides is an opportunistic infection caused by an aerobic actinomycete, which, in the immunocompromised host, can be associated with severe invasive disease with a predilection for the brain.

METHODS AND RESULTS

The authors describe a 62-year-old man with a malignant thymoma that was clinically responsive to oral prednisone. N. asteroides sepsis subsequently developed, leading to his death.

CONCLUSIONS

Nocardiosis should be considered a potential pathogen in this immunocompromised setting.

Electromagnetic midsagittal articulometer systems for transducing speech articulatory movements

This paper describes two electromagnetic midsagittal articulometer (EMMA) systems that were developed for transducing articulatory movements during speech production. Alternating magnetic fields are generated by transmitter coils that are mounted in an assembly that fits on the head of a speaker. The fields induce alternating voltages in a number of small transducer coils that are attached to articulators in the midline plane, inside and outside the vocal tract. The transducers are connected by fine lead wires to receiver electronics whose output voltages are processed to yield measures of transducer locations as a function of time. Measurement error can arise with this method, because as the articulators move and change shape, the transducers can undergo a varying amount of rotational misalignment with respect to the transmitter axes; both systems are designed to correct for transducer misalignment. For this purpose, one system uses two transmitters and biaxial transducers; the other uses three transmitters and single-axis transducers. The systems have been compared with one another in terms of their performance, human subjects compatibility, and ease of use. Both systems can produce useful midsagittal-plane data on articular movement, and each one has a specific set of advantages and limitations. (Two commercially available systems are also described briefly for comparison purposes). If appropriate experimental controls are used, the three-transmitter system is preferable for practical reasons.

Palpable abnormalities of the breast not requiring excisional biopsy

The evaluation of a patient with a palpable abnormality of the breast typically includes physical examination, mammography and fine needle aspiration biopsy (FNAB) with cytologic interpretation of the aspirate. If the findings of these three diagnostic modalities are negative for malignancy, the current standard of care is to proceed to surgical biopsy to confirm the benign nature of the lesion. The current study was done to identify a subset of patients who could be safely observed without surgical (histologic) biopsy. These patients fulfilled specified criteria on physical examination, mammogram and needle sensation when the FNAB needle entered the lesion. Results of the cytologic studies of the FNAB were used as a corroborative rather than as a diagnostic test. Of 305 patients with mammary abnormalities, 106 were identified with "subsuspicious" lesions. Seven of the latter patients underwent surgical biopsy, four because the results of cytologic studies of FNAB revealed cytologic atypia. One of the four patients had infiltrating ductal carcinoma. All other patients have had follow-up evaluation for a mean of 61 months (range of 43 to 74 months). No carcinomas have developed at the subsuspicious site. The current study is the first to clearly define a subset of patients with palpable abnormalities of the breast who do not require surgical biopsy.

Vitamin E in the treatment of chemotherapy-induced mucositis

PURPOSE

To determine the efficacy of vitamin E in the treatment of chemotherapy-induced mucositis in patients with malignancy.

PATIENTS AND METHODS

A randomized, double-blind, placebo-controlled study was performed to evaluate the efficacy of topical vitamin E in the treatment of oral mucositis in patients receiving chemotherapy for various types of malignancy. A total of 18 patients, 17 of whom had solid tumors and one with acute leukemia, were included in this study. Lesions were observed daily prior to and 5 days after topical application of either vitamin E or placebo oil.

RESULTS

Six of nine patients receiving vitamin E had complete resolution of their oral lesions. In eight of nine patients who received placebo, complete resolution of their oral lesions was not observed. This difference is statistically significant (p = 0.025 by Fisher's exact test). No toxicity was observed in this study.

CONCLUSION

These results suggest that vitamin E may be an effective therapy in patients with chemotherapy-induced mucositis.

Noninvasive estimation of cardiac output with nonprescribed breathing

A noninvasive method to estimate cardiac output Q without special patient cooperation was developed by modifying a previous acetylene-helium (C2H2-He) rebreathing technique (ART). Estimation of Q using ART is based on a single-compartment model that is valid only under prescribed breathing; e.g., fast, deep breathing, and emptying of the rebreathing bag on each breath. To make the ART less dependent on subject cooperation, a more sophisticated mathematical model and estimation method are needed. For this purpose, we modeled the C2H2 and He concentration dynamics at the mouth over successive breaths using a multi-compartment model. This model takes into account the effects of breathing pattern, compartmental volumes, and gas solubility. From computer simulations and sensitivity analysis, we found that Q could be estimated from the available data with adequate precision. Our model and estimation method were tested on a group of six normal adult subjects, at rest and during submaximal exercise (75 watts). Estimates of Q from our new method (6.5 +/- 0.4 L/min at rest, 12.5 +/- 0.4 L/min at 75 watts) were in agreement with those obtained using a previous ART (7.0 +/- 0.3 L/min at rest, 12.6 +/- 0.5 L/min at 75 watts). We conclude that this approach promises to provide reliable estimates of Q in patients (e.g., children and elderly), at rest and during exercise, without the need of prescribed breathing patterns or changes in rebreathing bag volume.

Surgical prophylaxis of malignant melanoma

A review of a 14-year experience with prophylactic pigmented skin lesion removal is presented. Data obtained during a 4-year interval of this 14-year experience is analyzed specifically. During this 4-year interval, 250 patients with melanoma were seen. Of these patients, 75 with a history of stage I (localized) melanoma and three patients with stage II (history of controlled regionally metastatic melanoma) underwent removal of multiple skin lesions on a prophylactic basis. Of the removed lesions, 28% showed hyperplasia, atypia, dysplasia, or melanoma. Nine unsuspected in situ, or level I melanomas, and three unsuspected invasive melanomas were removed from these 75 melanoma patients while excising lesions prophylactically during the 4-year interval. It is estimated that four to six additional melanomas were prevented by excision of precursor lesions. During the same 4-year interval, an additional 112 of approximately 1000 patients without a previous history of melanoma underwent prophylactic lesion removals. In 31% of the 112 patients, there was a history of melanoma in a first-degree relative. In 22% of the removed lesions there was hyperplasia, atypia, or dysplasia. Three cases of melanoma in situ were detected and it is estimated that an additional three to five cases of melanoma were prevented. Atypical findings occurred in 71, or 63%, of the patients biopsied, which represented 7% of the approximately 1000 patients screened. During the 4-year interval, an average of 17.7 lesions were removed from each of the 190 melanoma and nonmelanoma patients undergoing prophylactic skin lesion excision. This was accomplished in one to four sessions per patient. This average reflects only those patients who underwent one excision or more and does not include those patients treated without operation. When including the nonoperated patients screened during this interval, the average number of lesions removed was 2.7 per patient. Death from new melanomas was prevented during the 14-year period of this study as evidenced by the fact that no patient died or developed metastatic disease from a cutaneous melanoma that was not apparent or known about at the time of first examination.

Continuous intravenous infusion of morphine for severe dyspnea

We describe eight patients who had terminal lung cancer causing severe dyspnea unrelieved by oxygen, nonnarcotic drugs, or intermittent bolus narcotics. We treated these patients with continuous intravenous infusion of morphine, beginning with bolus IV injections of 1 or 2 mg of morphine every 5 to 10 minutes until the patient reported relief. A continuous morphine infusion was then started, with the hourly dose equal to 50% of the cumulative bolus dose. Vital signs, degree of sedation, and blood gases were serially followed. Six patients achieved good dyspnea relief, one had moderate relief, and one had a poor response. Variable changes were noted in the PaO2, whereas PaCO2 steadily increased in five of seven patients, and pH decreased in six. There was little change in systolic blood pressure or pulse, and only one individual had less than 10 respirations per minute. The major side effect of treatment was sedation, treated by temporarily discontinuing morphine until the patients' mental status improved and then restarting the infusion at a 50% lower hourly morphine dose. Mean time of study was 30 hours (range 16 to 87 hours). Seven of the eight study patients died during treatment. Whether morphine therapy shortened survival is uncertain. We conclude that continuous morphine infusion is effective therapy for severe dyspnea. The treatment is ethically justified. Relief of suffering is the primary goal of therapy, and less risky treatments are unavailable.

Hypotension and disseminated intravascular coagulation following intralesional bacillus Calmette-Guérin therapy for locally metastatic melanoma

Four patients developed serious hypotension and signs of disseminated intravascular coagulation shortly after a second round of Tice bacillus Calmette-Guérin (BCG) injections into locally recurrent cutaneous melanoma satellite nodules. Each of these patients survived following intensive therapy with isoniazid, pyridoxine, steroids, pressors, antibiotics, and cardio-renal support including, in one case, three acute hemodialyses. Plasma specimens from two of the four patients caused gelation of lysate from the amebocytes of Limulus polyphemus, indicating the presence of endotoxin or an endotoxin-like substance. In vitro studies on the BCG preparations led us to conclude that this endotoxin activity in the plasma is not the result of direct injection of endotoxin with the BCG preparation, but rather from release of endotoxin from endogenous sources, such as the intestinal tract during a period of relative hypotension following an allergic reaction. Prior immunity appeared to be the consistent factor in the toxic reactions reported herein. Finally, we present recommendations for serial monitoring of these patients and discuss the use of an alternative agent for intralesional therapy.