Lack of professional latitude and role problems as correlates of propensity to quit amongst nursing staff.

Which job stressors are the best predictors of propensity to quit among the nursing staff in emergency wards and intensive care units are explored in this paper. Employees of 30 Quebec hospitals (i.e. 60 wards in total) participated in the study (n = 1237). Stepwise multiple regression revealed that lack of professional latitude and role problems are the best predictors of the intention to quit the organization among all nursing staff. These two job stressors are briefly addressed in the context of intervention and possible remedies aiming at improving quality of life, mental health and decreasing the rate of turnover. It is argued that such intervention would benefit the nurses, the quality of patient care, as well as the respective hospitals.

Intrinsic job stress and diastolic blood pressure among female hospital workers.

The present study of 375 female hospital workers assesses the impact of two specific dimensions of vocational stress on standing diastolic blood pressure. Both intrinsic (pertaining to job content) and extrinsic (associated with job context) stressors were examined in this study. Diastolic blood pressure was found to be significantly related to scores on an intrinsic stress measure, but not with the extrinsic one, even after the contribution of obesity and age levels were controlled. However, the effect of intrinsic stress was only found to be significant among women younger than 35. We believe this to be preliminary evidence that perceived dimensions of chronic intrinsic role stressors can be significant psychosocial correlates of diastolic blood pressure.

Circulatory changes in newborn lambs with experimental polycythemia: comparison between fetal and adult type blood.

Hemodynamic effects of increased hematocrit were compared in two groups of newborn lambs. In the first group (fetal type blood), exchange transfusions were carried out using packed red blood cells obtained from newborn lambs within one to two hours after birth. In the second group (adult type blood), the same procedure was carried out using adult sheep blood. In both groups, hematocrit values ranging between 70% and 80% were reached. The increase in hematocrit caused a decrease in cardiac output due to an increase in peripheral resistance. Pulmonary resistance increased more than systemic resistance. However, the increase in pulmonary resistance was significantly greater in the polycythemic newborn lambs with adult blood. A right-to-left shunt through a patent ductus or a foramen ovale was noted in six of the eight lambs included in this group. On the other hand, none of the seven polycythemic newborn lambs with fetal blood developed signs of right-to-left shunting. It is concluded that during neonatal polycythemia, the level of hematocrit is not the sole factor responsible for the hemodynamic changes observed. Other unknown influences related either to the red cells or the plasma must impinge upon the pulmonary circulation to alter vascular resistance.

The effect of high or low oxygen affinity red cells on tissue oxygenation and myocardial function in hypoxic newborn lambs with or without hypercapnia.

In order to compare high and low oxygen affinity blood under conditions of severe respiratory failure, the effects of a high or low P50 were evaluated in two groups of newborn lambs (P50, 20 mmHg versus 30 mmHg), under conditions of hypoxic hypoxia (Fio2, 10%) and hypercapnic hypoxia (Fio2, 10% and Fico2, 10%). Data on cardiovascular function, blood gas parameters, and tissue oxygenation were collected under normoxic conditions and during severe hypoxia. During hypoxic hypoxia, a higher arterial oxygen content was noted in the high affinity group throughout the experiment; however, there were no significant differences detected in the remainder of the parameters studied. During hypercapnic hypoxia, the position of the oxygen dissociation curve did not cause any significant differences. When, however, hypercapnic hypoxia was compared to hypoxic hypoxia, there was a significant increase in cardiac output and myocardial contraction during hypercapnia.

Oxygenation in anemic newborn lambs with high or low oxygen affinity red cells.

Experiments to determine the effect of the oxygen-hemoglobin dissociation curve on oxygen delivery during neonatal anemia, were carried out on 15 sedated and ventilated lambs less than 48 hr of age. Eight of the animals were exchange transfused with adult blood. The P50 of the exchange transfused group was 32.1 mm Hg (low O2 affinity) compared to 19.4 mm Hg for the controls (high O2 affinity). The animals were made anemic by isovolumic exchange transfusions with plasma. At different levels of hemoglobulin defined as mild (8 mg/100 ml), moderate (6 mg/100 ml), and severe (4 mg/100 ml) anemia, tissue oxygenation, hemodynamic status, and blood gases were compared. Mixed venous PO2 was significantly lower in the high affinity group throughout this study. Cardiac output was significantly greater in the low affinity group during severe anemia. Oxygen consumption remained stable in the low affinity group, but decreased significantly in the high affinity group when the anemia was severe. The data indicate that during severe anemia, blood with a high P50 is more capable of adequately oxygenating tissues than that with a low P50.

Evidence for the participation of sodium-sensitive pontine catecholaminergic neurons in the maintenance of DOCA-sodium hypertension in rats.

1. A reduced noradrenaline turnover rate has been previously demonstrated in the brain stem of deoxycorticosterone acetate (DOCA)-sodium hypertensive rats. In the present study, the turnover rate was measured in smaller brain regions and the effect of sodium depletion was studied on the turnover rate of these regions. 2. Catecholamine turnover rate was significantly reduced only in the pons, was slightly but not significantly reduced in the thoracic spinal cord and was normal in the upper and lower medulla oblongata, in the mesencephalon, in the hypothalamus and in the telencephalon. 3. The administration of a sodium-free diet for 3 weeks lowered significantly the blood pressure and concomitantly accelerated the turnover rate in the pons area of DOCA hypertensive rats. 4. It is concluded that pontine catecholaminergic fibres, sensitive to sodium balance, might be involved in the maintenance of DOCA-sodium hypertension in the rat.

Circulating catecholamine levels in human and experimental hypertension.

The radiometric enzymatic technique of Coyle and Henry (J. Neurochem. 21: 61-67, 1973) was adapted to the measurement of serum catecholamines. This technique requires less time than other enzymatic techniques and is sensitive to quantities as small as 25 pg. In normotensive subjects lying supine for 20 minutes serum catecholamine levels averaged 0.218 ng/ml, with no obvious sex or age difference. Under these standardized conditions, the circulating catecholamine levels for a given individual are highly reproducible on different days over a period of several months. In 22 patients with essential hypertension, circulating levels were significantly higher, with an average of 0.370 ng/ml. More than 50% of the hypertensive patients had values greater than the highest value measured in normotensives. Systolic blood pressure and heart rate were significantly higher in the hypertensive group with elevated levels of circulating catecholamines than in the hypertensive group with normal levels. In one model of experimental hypertension, produced in the rat by administration of deoxycorticosterone acetate (DOCA) and saline for 4-8 weeks, serum catecholamines were significantly elevated. These findings suggest that the sympathetic system may play an important role in maintaining an elevated blood pressure in experimental hypertension and in a significant proportion of patients with essential hypertension.