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Biomedical subjects

S Cotev

Publications and source records attributed to S Cotev.

At least 73 records · Page 4Linked to original sources

The variable effect of PEEP in acute respiratory failure associated with multiple trauma.

Both short and longterm effects of positive end-expiratory pressure (PEEP) on oxygenating capacity (OC) were investigated in three groups of patients with acute respiratory failure following multiple trauma (MT). Group A consisted of six patients with "uncomplicated" MT; Group B, eight patients with MT and generalized sepsis; Group C, nine patients with MT and lung contusion. OC was evaluated in terms of PaO2/FIO2 and P(A-a)DO2 on FIO 2 = 1.0. OC was markedly and equally reduced in the three patient groups before use of PEEP. The use of a mean PEEP of 6-7 cm H2O resulted in an initial improvement in mean PaO2/FIO2 of 152.5, 36.1, and 59.2 mm Hg, and an overall improvement of 196.8, 57.5, and 107.0 mm Hg in Groups A, B, and C, respectively. There was a similar improvement in both the initial and the overall effect of PEEP on P(A-a)DO2 in the three groups. The difference in the improvement in OC due to PEEP was statistically significant between Groups A and B. It is concluded that acute respiratory failure following MT includes a wide spectrum of clinical syndromes, and that the improvement in OCT due to PEEP depends on the clinical sydrome that is responsible for the respiratory failure associated with MT.

Acute Disease↗

The hemodynamic effects of dopamine following cardiopulmonary bypass.

The hemodynamic effects of dopamine were studied in 19 patients following intracardiac operation or myocardial revascularization using extracorporeal circulation. The heart rate, mean blood pressure, central venous pressure, left atrial and pulmonary artery pressures, cardiac output, and urine output were recorded before and at the end of one-hour infusions of dopamine at 5, 10, and 15 mug/kg/min. Infusion of 5 mug/kg/min of dopamine resulted in the highest gain in cardiac output and stroke work without an increase in myocardial oxygen consumption, as evidenced by lack of significant rise in heart rate. In addition, this dosage was not accompanied by an increase in pulmonary or systemic vascular resistance, nor were other untoward effects observed after administration of 5 mug/kg/min of dopamine.

Blood Pressure↗

Cardiopulmonary effects of volume loading in patients in septic shock.

The effect of volume loading in 20 patients with clinical and bacteriological evidence of generalized sepsis was studied. The patients were divided into two groups according to their response to volume loading. Group A included 9 patients in whom the initial pulmonary capillary wedge pressure (PWP)was lower than the central venous pressure (CVP). In this group the intravenous administration of 5089+/-409ml/24 hr fluids was accompanied by a significant rise in blood pressure from 94.4+/-9.3mm Hg to 118.9+/-6.3 MM Hg with no significant change in pulse rate or CVP. PWP rose from 5.7 +/- 1.8 to 10.0 +/- 1.4. The rise in cardiac output from 8.0+/-1.3 liter/min to 9.7+/-1.1 liter/min was not statistically significant. Group B included 11 patients in whom the initial PWP was higher than the CVP. In this group, signs of fluid overloading appeared after administration of 3151+/-540ml/24 hr. There was no significant change in blood pressure, pulse rate, CVP, PWP or cardiac output. Urine output was adequate in both groups. This volume load did not affect pulmonary oxygenating capacity (PaO2/F1O2) and effective lung compliance in both groups, but the maintenance of an unchanged oxygenating capacity necessitated an increase in PEEP in some patients. Thus, synchronous monitoring of PWP and CVP in septic shock is helpful in selecting patients (Group A) who will best respond to fluid loading without deterioration of pulmonary oxygenating capacity. PEEP ventilation may be necessary in some patients to maintain the favorable effect of volume loading.

Adult↗

The role of hypovolemic stress in the production of fat embolism in rabbits. 1. Morphologic alterations of the lungs.

In rabbits, an experimental model of fat embolism was produced that simulates the course of events in the clinical situation. Small doses of fat-cell suspension (0.075 ml/kg of body weight), prepared by collagenase treatment of homologous adipose tissue, were injected intravenously. Concomitantly, hypovolemia was produced in two animal groups by either withdrawing 20 percent of the estimated blood volume or by application of a hind-limb ischemic tourniquet for 90 minutes. The presence of pathoanatomic characteristics typical of fat embolism was evaluated by recording lung/body weights, macroscopic appearance, and semiquantitative microscopic estimation in the lungs of edema, hemorrhage, atelectasis, intravascular coagulation, and leukocytic thrombi. Mean indices of lung/body weight were higher in all animals receiving injections of fat-cell suspension, as compared to controls. The score for microscopic generalized pulmonary damage was significantly higher in rabbits exposed to both fat-cell injections and hypovolemia than in controls or after fat-cell injections alone. It is concluded that hypovolemia enhances the development of fat embolism in rabbits subjected to small doses of fat-cell suspension.

Animals↗

The role of hypovolemic stress in the production of fat embolism in rabbits. 2. Changes in arterial blood gas levels and static compliance.

The purpose of this study was to assess the possible role of hypovolemia as a factor in the production of impaired pulmonary function in pulmonary fat embolizaiton. Iv vivo static lung compliance was measured by inflating the lungs with known volumes of air and recording the transpulmonary pressure, monitoring intraesophageal pressure as an index of intrapleural pressure. Arterial blood was drawn from the central artery of the ear. Embolization was produced by the intravenous injection of homologous fat cells either as the sole experimental procedure or in conjunction with hypovolemic shock. Two types of shock were studied. In one, 20 percent of the blood volume was removed, producing hypovolemia associated with hemodilution, and in the other a tourniquet was applied to induce hypovolemia and hemoconcentration. The results indicate that embolization is associated with significantly greater impairment of pulmonary function if it develops on a background of shock than if it occurs in an otherwise healthy animal. These pathophysiologic findings parallel the results of a morphologic study.

Adipose Tissue↗

Anesthesia in the Yom Kippur war.

The role of the anesthetist in the treatment of battle casualties is discussed in the light of personal experience in a field hospital and in the rear during the Yom Kippur War of October 1973. Resuscitation and intensive care both before and after evacuation play an important part in reducing mortality, and the importance of providing adequate facilities for these functions in the battle area as well as at the base is emphasized.

Anesthesia↗

Carbonic acid production and the role of carbonic anhydrase in decarboxylation in brain.

Sudden oxygenation of a thin film of rat brain homogenate, suspended between the surface of a glass pH-sensitive electrode and a gas-permeable membrane, is accompanied by a fall in pH, which is greater when carbonic anhydrase is inhibited. The result suggests that oxidative decarboxylation yields carbonic acid (HCO(3)- and H(+)), which dissociates to form molecular carbon dioxide. Brain carbonic anhydrase facilitates the formation of carbon dioxide from the decarboxylation products.

Acetazolamide↗