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Biomedical subjects

S E Mace

Publications and source records attributed to S E Mace.

24 records · Page 2Linked to original sources
PubMed1983

Echocardiographic and hemodynamic findings in isolated symptomatic coarctation of the aorta in infancy.

Echocardiographic findings and cardiac catheterization data were evaluated in 18 infants less than 1 year old in order to define anatomical or pathophysiological features that were associated with early cardiac decompensation. The infants could be divided into three groups: Group I (10 patients) had left ventricular dilatation and depressed contractility in response to the severe systemic hypertension. Group II (3 patients) had marked myocardial hypertrophy In response to the systemic hypertension. Group III (5 patients) were the youngest patients and had findings of right ventricular volume overload and pulmonary hypertension. This study demonstrates that, in early infancy, the ventricular response to simple coarctation of the aorta is variable in infants in a state of cardiac decompensation. The different echocardiographic and hemodynamic findings may be a consequence of the lesion exerting its influence at various stages of the patients' intrauterine or postnatal life. In most patients, resection of the coarctation results in rapid normalization of the echocardiographic findings.

Aortic Coarctation↗
PubMed1983

Autonomic nervous control of heart rate: sympathetic-parasympathetic interactions and age related differences.

A factorial experimental design was used to quantify the changes in heart rate produced by stimulation of the cardiac sympathetic and vagal nerves in eleven adult dogs and four puppies, and to quantify the extent of the peripheral sympathetic-vagal interactions. The chronotropic responses to autonomic stimulation were significantly less in the puppies than in the adult dogs, which suggests that autonomic regulation is functionally incomplete in the puppies. In both adult dogs and puppies, the chronotropic responses to autonomic nerve stimulation were bilaterally asymmetrical. The heart rate responses to a given level of right-sided stimulation of either the sympathetic or vagal nerves were greater than those to comparable left-sided stimulation. In both adult dogs and puppies, there were significant sympathetic-vagal interactions, such that the sympathetic enhancement of heart rate was less effective the higher the background level of vagal activity. The sympathetic-vagal interactions were prominent in the puppies as well as in the adult animals, regardless of whether the stimulated sympathetic and vagal nerves were located ipsilaterally or contralaterally to one another. Thus, the mechanisms responsible for the sympathetic-vagal interactions appear to be fully developed in puppies. Also, the cardiac sympathetic nerve endings that originate from one side of the body must lie in close apposition to the cardiac vagal nerve endings that originate from either the same side or from the opposite side of the body.

Aging↗
PubMed1983

Neural control of heart rate: a comparison between puppies and adult animals.

The heart rate responses to stimulation of the right and left cardiac autonomic nerves were evaluated in 20 puppies and 17 adult dogs. In every puppy and adult dog, the changes in heart rate were much greater with right- than with left-sided stimulation of the vagal or sympathetic nerves. At maximal stimulation frequencies, the % changes in heart rate (mean +/- S.E.M.) were: right stellate, adults +50.0 (+/- 5.1) and puppies +23.6 (+/- 2.8); left stellate, adults +20.0 (+/- 2.4) and puppies +5.6 (+/- 2.3); right vagus, adults -74.0 (+/- 5.2) and puppies -43.6 (+/- 3.3); and left vagus, adults -44.1 (+/- 2.0) and puppies -24.9 (+/- 2.3). At any given stimulation frequency, the heart rate responses were significantly greater in adult dogs than in puppies, with either stellate or vagal stimulation. In 47% of the puppies and in 11% of the adult dogs, left stellate stimulation had no detectable effect on heart rate, although there was evidence of an increase in blood pressure in each of these animals. In these animals, fibers from the left stellate ganglion did not innervate the sinoatrial node.

Age Factors↗
PubMedDate not supplied

Cricothyrotomy.

Cricothyrotomy is a simple and safe method for obtaining airway control during situations in which endotracheal intubation is difficult or contraindicated. Cricothyrotomy can be a lifesaving procedure. It can be done quickly in emergency situations by nonsurgeons with a minimum of necessary equipment and without requiring an operating room. The anatomy, specific techniques or procedure, indications and contraindications, and the advantages and disadvantages are discussed.

Airway Obstruction↗
PubMedDate not supplied

The impact of paramedics on out-of-hospital cardiac arrests in a rural community.

OBJECTIVE: To determine whether paramedics influence the outcome of cardiac arrest patients in a rural area. METHODS: Retrospective analysis of cardiorespiratory arrest patients in rural southeast Alaska from 1987 to 1996. RESULTS: Paramedics treated 37 patients and advanced life support emergency medical technicians (EMT-IIIs) treated 34 patients. Demographics/CPR variables of the two groups were similar. Return of spontaneous circulation (ROSC) was 46% (17/37) for the paramedic-treated patients and 18% (6/34) for the EMT-III-treated patients (p = 0.01). Intensive care unit (ICU) admission was 38% (14/37) for the paramedic-treated patients and 15% (5/34) for the EMT-III-treated patients (p < 0.03). Discharge from the hospital neurologically intact was 20% (7/35) for the paramedic-treated patients and 9% (3/34) for the EMT-III-treated patients (p = NS). Two patients in the paramedic-treated group had ROSC and survived in the local hospital ICU for several days before being transferred to a tertiary care hospital in another state and were lost to follow-up for the discharge-from-hospital-neurologically-intact category but were included in the ROSC and ICU admission analysis. CONCLUSION: In this rural setting, a paramedic on the scene significantly improved the ROSC (paramedics = 46% vs 18% for EMT-III, p = 0.01) and survival to ICU admission (38% vs 15%, p = 0.03). The presence of a paramedic on the scene increased survival to hospital discharge neurologically intact (20% vs 9%), although this was not statistically significant.

Aged↗