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Biomedical subjects

S S Haas

Publications and source records attributed to S S Haas.

13 recordsLinked to original sources

Limitations of liability insurance.

In the unfortunate event that you are sued for malpractice, the following suggestions could maximize the benefits of your professional liability insurance policy: Do not contact the claimant, because any statements you make can be used against you in a suit. Provide the insurer with as much information as possible. Monitor the case regularly by contacting the insurance adjuster assigned to the case and request copies of all documents generated. Communicate your feelings with the company about defending or settling the case. If you completely violated a standard of care such as giving an IV push medication to the wrong patient because of failure to check the patient's name bracelet, try to settle this case out of court. A jury would not likely be sympathetic to a nurse who injured a patient in this manner. Review the entire medical record and discuss your analysis with your attorney. Remember, as a policyholder, you have the right to demand that your claim be handled by a competent, professional lawyer. Unlike other professionals, attorneys are not required to have national certification. Defendants have the right to ask assigned attorneys about their malpractice experience. Does the attorney have a working knowledge of the procedures and technical jargon concerning the case? How many similar cases has the attorney handled? You have a right to these answers.

Critical Care↗

Low back pain in the competitive tennis player.

The etiologies of low back pain and the biomechanics and pathology of the lumbar spine as they relate to tennis stroke mechanics have been reviewed, and a treatment protocol has been presented. A recent survey of the Men's Professional Tennis Tour is the only article found that discusses low back pain in tennis players; the orthopaedic and sports medicine literature is otherwise devoid of any relevant studies. Because this one survey indicates that 38 per cent of 143 tennis players missed at least one tournament because of low back problems, it seems obvious that an epidemiologic study on low back pain in racquet sports is vital to a more thorough understanding of the problem.

Athletic Injuries↗

Effect of mechanical loading on breathing patterns in women.

First-breath ventilatory responses to graded inspiratory elastic and resistive loads were obtained from 80 women unfamiliar with respiratory experimentation. For each load 1) responses from different subjects ranged from a weak tidal volume defense coupled with an increased breathing frequency to a strong tidal volume defense coupled with a decreased frequency; 2) strong tidal volume defenders employed longer inspirations than did weak tidal volume defenders; and 3) individual respiratory frequency responses were mediated by changes in inspiratory and/or expiratory timing. Thus the group response was qualitatively the same as that reported for 80 men. Quantitatively, however, mean inspiratory airflow responses of women exceeded those of men by an amount attributable to women's higher intrinsic respiratory elastance. Tidal volume responses, on the other hand, did not differ significantly, suggesting that men and women produce different neural adjustments to loads. In support of this hypothesis, analysis of respiratory timing responses revealed that 1) men actively prolonged inspiration more than women during resistive loading; and 2) women actively shortened inspiration more than men during elastic loading. These findings indicate that the load-compensating behavior exhibited by men and women is similar but not identical.

Adult↗

Ventilatory adjustments during sustained mechanical loading in conscious humans.

Ventilatory responses to inspiratory elastic and resistive loads of 67 men were analyzed. During the 1st, 5th, and 10th consecutively loaded breaths 1) individual responses ranged from a rapid-shallow to a slow-deep breathing pattern; 2) strong tidal volume (VT) defenders employed longer inspirations than did weak VT defenders; and 3) individual frequency responses were mediated by changes in inspiratory and/or expiratory timing. Thus the group response was qualitatively similar on the 1st, 5th, and 10th loaded breaths. Quantitatively, however, the group's mean minute ventilation increased throughout each episode owing to progressively larger tidal volumes coupled with equal breathing frequencies. During elastic loading this amplified VT defense was achieved by stronger inspirations with no systematic changes in timing, whereas during resistive loading it was achieved both by stronger and longer inspirations. Inspiring 5% CO2 induced a degree of hypercapnia exceeding that accompanying mechanical loading and yet elicited a comparatively modest enhancement of respiratory output. These findings suggest that in conscious humans 1) repeated mechanical loading activates neural load-compensating mechanisms; 2) the range of these neural adjustments varies with both load size and type; and 3) the stimulus to initiate this behavior is largely nonchemical.

Adolescent↗

Effect of thoracic deafferentation on load-compensating mechanisms in humans.

First-breath responses to graded elastic (delta E) and resistive (delta R) loads in 29 cervical cord-injured and 80 normal men were compared with those predicted assuming identical respiratory muscle pressure (Pmus) wave forms in the unloaded and loaded states. The cord-injured group's mean actual and predicted inspiratory duration (TI) responses were equal, indicating that the average duration of their phrenic discharge remained constant during both delta E and delta R. Their mean expiratory duration (TE) responses fell short of predictions with delta E but exceeded predictions with delta R, signifying that a neural mechanism hastened inspiration following delta E but postponed it following delta R. TE/(pred TE) values (an index of phrenic timing) from different loads were proportional to concomitant TI responses but not to indices of diaphragmatic force [peak Pmus, (VT/TI)/(pred VT/TI)], movement (VT, VT/TI), or duration of contraction [TI/(pred TI)]. These findings suggest that oropharyngeal and/or pulmonary receptors signaling airflow duration, rather than diaphragmatic length or tension receptors, adjust phrenic motoneuron timing during mechanical loading. The cord-injured group produced a normal tidal volume (VT) defense coupled with a depressed frequency (f) response to delta E and, conversely, a weak VT defense coupled with a normal f response to delta R. Since both groups' VT/TI responses surpassed predictions equally, the cord-injured group's deficit was attributable entirely to impaired regulation of TE during delta E and TI during delta R. Thus chest wall receptors modulate duration and timing, but probably not average intensity, of the phrenic output during loading. Nearly one-third of the normal, but virtually none of the cord-injured, samples prolonged TI against large delta R and shortened TI agaist large delta E, suggesting that thoracic deafferentation impairs human ability to distinguish large delta R from delta E. These latter findings support the hypothesis that chest wall afferents subserve perception of respiratory force or position in humans.

Afferent Pathways↗

A proposed specification for acrylic bone cement.

A proposed specification covering handling characteristics and physical and chemical properties of bone cement composed primarily of methyl methacrylate has been prepared on the basis of data from the authors' studies and from various other sources. Under handling characteristics, requirements included relate to dough, handling and setting time, proper plasticity for insertion and temperature rise on setting. Mechanical properties specified include compressive strength and indentation and recovery characteristics. Maximum limits are proposed for water sorption and solubility. Suggested packaging requirements are also included.

Bone Cements↗

A characterization of polymethylmethacrylate bone cement.

Polymethylmethacrylate cement is characterized in terms of chemical composition, handling characteristics, and physical properties; the dough time, setting time, handling time, and temperature rise were found to be most affected by environmental temperature and kneading of the dough mass. As the set material ages, the residual monomer content gradually decreases and the strength increases. A volume shrinkage of up to 5 per cent was observed. The porosity, which is increased by rapid mixing, may reach 10 per cent. The mechanical properties of the cement approximate those of polymethylmethacrylate denture base material. Some variability encountered in the handling qualities of the cement could be attributed only to the variability of different batches.

Barium Sulfate↗

Intensive care in small hospitals.

The scene: a small ICU in a 120-bed community hospital with no resident house staff. Emergency coverage is assigned to the emergency room physician. A patient in the ICU has cardiac arrest. His physician is called but cannot come to the hospital immediately, and the emergency room physician is attending a seriously injured patient. In the critical interim, paramedical professionals must shoulder the heavy responsibilities for decisions and interventions.

Allied Health Personnel↗