Biomedical subjects

N M Lazar

Publications and source records attributed to N M Lazar.

5 recordsLinked to original sources

PubMed2001

Bioethics for clinicians: 24. Brain death.

Brain death is defined as the complete and irreversible absence of all brain function. It is diagnosed by means of rigorous testing at the bedside. The advent of neurologic or brain death criteria to establish the death of a person was a significant departure from the traditional way of defining death and remains ethically challenging to some. We review the ethical, cultural, religious and legal issues surrounding brain death and outline an approach to establishing a diagnosis of brain death in clinical practice.

Adult↗

PubMed1996

Bioethics for clinicians: 5. Substitute decision-making.

Substitute decision-making is a means of making health care decisions on behalf of people who are incapable of making these decisions for themselves. It is based on the ethical principle of respect for autonomy. Substitute decision-making poses two main questions: Who-should make the decision for the incapable person, and, How should the decision be made? Because the applicable statutory and common law varies across Canada, clinicians should become familiar with the legal requirements of their own province or territory.

AIDS Dementia Complex↗

PubMed1986

Hemodynamic assessment and management of patients with the adult respiratory distress syndrome.

In summary, ARDS and the combination of MV and PEEP may have complicated hemodynamic effects in terms of cardiac output and regional blood flow. These effects should be assessed primarily in terms of the adequacy of tissue oxygenation. Hemodynamic management of patients with ARDS should be aimed at improving tissue oxygenation by reducing metabolic needs, and improving both the arterial oxygen content (Table 3) and the cardiac output (Table 4). In most patients, these goals can be realized simultaneously.

Cardiac Output↗

PubMed1985

Effect of increases in lung volume on clearance of aerosolized solute from human lungs.

To study the effect of increases in lung volume on solute uptake, we measured clearance of 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) at different lung volumes in 19 healthy humans. Seven subjects inhaled aerosol (1 micron activity median aerodynamic diam) at ambient pressure; clearance and functional residual capacity (FRC) were measured at ambient pressure (control) and at increased lung volume produced by positive pressure [12 cmH2O continuous positive airway pressure (CPAP)] or negative pressure (voluntary breathing). Six different subjects inhaled aerosol at ambient pressure; clearance and FRC were measured at ambient pressure and CPAP of 6, 12, and 18 cmH2O pressure. Six additional subjects inhaled aerosol at ambient pressure or at CPAP of 12 cmH2O; clearance and FRC were determined at CPAP of 12 cmH2O. According to the results, Tc-DTPA clearance from human lungs is accelerated exponentially by increases in lung volume, this effect occurs whether lung volume is increased by positive or negative pressure breathing, and the effect is the same whether lung volume is increased during or after aerosol administration. The effect of lung volume must be recognized when interpreting the results of this method.

Aerosols↗

PubMed1984

A comparison of in vivo and in vitro human airway reactivity to histamine.

To examine for a relationship between in vivo nonspecific bronchial reactivity to histamine and in vitro smooth muscle response to histamine, we performed inhalation dose-response curves prior to lung surgery in 12 patients and compared this with their bronchial smooth muscle response in vitro. In vivo reactivity was assessed by the provocative concentration of histamine resulting in a 20% fall in forced expiratory volume in one second (PC20), and in vitro reactivity was measured by the negative log of the molar concentration of histamine producing 50% maximal contraction (pD2) as well as maximal tension generated (Tmax). In addition, morphometric analysis was performed on the in vitro tissue to quantitate the amount of smooth muscle present. A wide range of in vivo responses was found in the 12 subjects (PC20-0.065 lead to 16). There was less in vitro variability and no correlation between PC20 and in vitro reactivity assessed by pD20 or Tmax or between PC20 and the percent of smooth muscle.

Aged↗