PubMed Health⌕ Search

Biomedical subjects

A J Erdmann

Publications and source records attributed to A J Erdmann.

At least 19 recordsLinked to original sources
PubMed1983

Pure oxygen breathing increases sheep lung microvascular permeability.

Sheep that breathe pure oxygen via a tracheostomy develop progressive respiratory failure and die within four days. The characteristic terminal findings include an increased water content of the lung, a decrease in lung compliance, and severe hypercarbia. To sequentially assess alterations of lung transvascular fluid dynamics during prolonged oxygen breathing the authors measured lung lymph flow (Q lymph), protein transport (Q protein), and pulmonary vascular pressures in five sheep with chronic lung lymph fistulas. No significant changes of lung transvascular fluid dynamics occurred during the first 60 hours of oxygen breathing, although an increasing trend of Q lymph and Q protein was demonstrable. However, after 72 hours of oxygen breathing, Q lymph, Q protein, and extravascular lung water had increased significantly without any change of pulmonary vascular pressures. The authors conclude that the toxic effects of oxygen on the lungs of sheep include a delayed but marked increase of pulmonary microvascular permeability to protein and fluid.

Animals↗
PubMed1982

Role of procaine and washed red cells in the isolated dog heart perfused at 5 degrees C.

Isolated dog hearts were perfused for 24 hours at 5 degrees C with one of three solutions: plain Krebs solution, Krebs solution containing 167 mg/L of procaine hydrochloride, or Krebs-procaine solution with washed red cells (hematocrit 2%). Coronary vascular resistance (CVR) of hearts perfused with Krebs solution alone increased sharply between the eighth and the twelfth hours of perfusion and then stabilized. Increase of myocardial firmness paralleled the increase of CVR. The addition of procaine to Krebs perfusate kept the heart flaccid and suppressed the steplike increase in CVR but failed to improve significantly the preservation of the hearts. The addition of washed red cells to Krebs perfusate kept CVR near baseline level, improved coronary perfusion flow, doubled myocardial oxygen consumption, reduced edema formation, and improved left ventricular stroke work (LVSW) of the preserved heart. This improvement seems mostly related to a mechanical effect of red blood cells on capillary flow distribution of the heart.

Animals↗
PubMed1981

Aortocoronary bypass grafting in patients without left main stenosis. Relation of risk factors to early and late survival.

Three-hundred and thirty-five patients without left main stenosis or recent acute myocardial infarction underwent isolated aortocoronary bypass grafting during 1974 and 1975. The hospital mortality was 2 per cent for the four-year predicted survival is 94 per cent. Neither the preoperative presence or absence of a progressive or unstable angina pattern, the extent of coronary artery disease, nor the left ventricular ejection fraction predicted postoperative survival. None of the 25 patients whose ejection fraction was 0.30 or less died in the perioperative period, and no late deaths occurred in this subgroup until after 36 months of follow-up, giving a predicted four-year survival rate of 82 per cent. With only one exception, patients in this subgroup were operated on because of angina, which was unstable in three-quarters of them. We believe that this study shows that patients with a severely reduced ejection fraction should not be refused aortocoronary bypass grafting if symptoms of angina are severe and predominate over symptoms of heart failure.

Coronary Artery Bypass↗
PubMed1980

Preservation of normal gas exchange with hemodilution in patients with pulmonary hypertension.

The relationship between the plasma colloid osmotic pressure/pulmonary capillary wedge pressure difference (PCOP-PCWP) and the development of gas exchange abnormalities was examined prior to, during, and after cardiac operations in 13 patients with pulmonary hypertension owing to mitral and/or aortic valvular disease. Alveolar-arterial oxygen tension gradient [P(A-a)DO2] and pulmonary shunt fraction (Qs/Qt) were used as indices of gas exchange impairment owing to accumulated lung water. During the baseline period, PCOP-PCWP was -8.5 +/- 2.6 mm Hg; P(A-a)DO2, 352.5 +/- 30.1 mm Hg; and Qs/Qt, 17.0% +/- 1.5%. There were no significant correlations between PCOP-PCWP and P(A-a)DO2 or Qs/Qt at any time during the study. Thus PCOP-PCWP does not predict susceptibility to lung water accumulation reliably in patients with pulmonary hypertension, and other protective factors may contribute to unimpaired gas exchange, even in the setting of profound hemodilution and low PCOP.

Adult↗
PubMed1979

Protection by plasma proteins of the isolated lamb heart perfused with stroma-free hemoglobin at 38 degrees.

Isolated lamb hearts were perfused for eight hours at 38 degrees with stroma-free hemoglobin solution (SFHS). The preservation of cardiac structure and function was studied. Control hearts perfused with blood (N = 6) developed no ventricular failure or significant weight gain (13% +/- 5), showed no alteration of cellular ultrastructure, and little interstitial edema. Hearts perfused with 7% (N = 7) or 11% (N = 5) SFHS contracted less well, became edematous (22% and 44% weight gain) and showed altered mitochondria, capillary endothelial swelling and hemoglobin extravasation into the interstitial space. The addition of 5-7% albumin to SFHS (N = 9) markedly reduced interstitial edema (weight gain 11% +/- 13), preserved mitochondria, prevented endothelial swelling, and limited transcapillary escape of hemoglobin. Thus isolated hearts perfused with SFHS develop vascular endothelial damage and an increase in capillary permeability. The addition of plasma proteins to the perfusate protects against this injury.

Animals↗
PubMed1979

Equilibration of intravascular albumin with lung lymph in unanesthetized sheep.

In 16 unanesthetized sheep with chronic lung lymph fistulas we measured pulmonary vascular pressures, lymph flow, lymph and plasma total protein and albumin concentration. We determined the rate of equilibration of radioiodinated albumin between plasma and lung interstitial fluid (lung lymph) in three steady-state conditions; baseline (n = 14), increased pulmonary microvascular pressure (n = 9) and increased microvascular permeability (n = 4). The tracer protein equilibration proceeded according to single compartment wash-in kinetics in all experiments. Lung lymph flow averaged 5.3 +/- 2.8 (S.D.)ml/h under baseline conditions, 16.1 +/- 10.6 ml/h during increased pressure and 37.3 +/- 29.4 ml/h during increased permeability. The half time of equilibration averaged 2.9 +/- 1.0 h, 2.2 +/- 1.0 h and 0.7 +/- 0.2 h, respectively. Lung interstitial fluid equilibrates with plasma proteins more rapidly than most other organs. The marked difference between increased permeability and the other conditions demonstrates the sensitivity of this method. No evidence was obtained that any tracer protein entered lung lymph within the caudal mediastinal lymph node.

Animals↗
PubMed1979

Lung transvascular fluid dynamics with extracorporeal membrane oxygenation in unanesthetized lambs.

Extracorporeal membrane oxygenation (ECMO) is used for long-term support of patients with acute respiratory failure. We investigated the effect of partial venoarterial (VA) and venovenous (VV) bypass with filler-free silicone spiral-coil membrane lungs on steady-state lung transcapillary fluid filtration in six unanesthetized lambs for periods of 11 to 32 hours. Using three thoracotomies we prepared animals to collect lung lymph; lymph obtained in this way is representative of lung interstitial fluid. By studying lymph flow and composition we demonstrated that the permeability of the pulmonary capillaries does not change during prolonged partial VV or VA bypass with a membrane lung. There was no accumulation of lung water during bypass, and lung protein and fluid leak neither increased not decreased with bypass flows equivalent to those used clinically. Thus prolonged use of ECMO in unanesthetized lambs appears to be neither harmful nor beneficial to the steady-state dynamics of fluid exchange in the lung. Furthermore, total pulmonary blood flow is not a determinant of net fluid filtration across the lung microcirculation.

Animals↗
PubMed1978

The effect of hemodilution with albumin or Ringer's lactate on water balance and blood use in open-heart surgery.

To determine the effect of intraoperative albumin administration on blood use, water balance, and postoperative clinical course, we studied two groups of adult cardiac surgical patients. Group I (30 patients) received 25 gm of albumin during withdrawal of 2 units of blood prior to cardiopulmonary bypass (CPB) and 50 gm of albumin in the oxygenator prime. Group II (32 patients) received no albumin prior to the end of CPB. No difference in clinical course could be identified, nor was there a significant difference in blood use. Group I patients had lower hematocrit values intraoperatively from the time of blood withdrawal until the conclusion of operation. Coronary artery bypass operations were associated with greater positive water balance than were heat valve operations. Forty-three percent of the patients having coronary artery bypass grafting had a positive water balance greater than 5 liters, whereas 50% of those undergoing valve procedures had a balance less than 3 liters. We conclude that the principal effect of withholding albumin under these circumstances is to increase net positive water balance. The greater positive water balance does not appear to be detrimental.

Adult↗
PubMed1978

Ventricular performance and myocardial water content during hemodilution in dogs.

In dogs anesthetized with chloralose-urethan on right heart bypass, left ventricular (LV) performance was assessed at constant LV stroke work before and for up to 2.5 h after crystalloid hemodilution was established. Lowering the hematocrit from 43.3 +/- 1.3% to 13.6 +/- 1.7% (SE) did not significantly change LV end-diastolic pressure (LVEDP) initially. After 80 min LVEDP increased slightly by 1.7 +/- 0.6 cmH2O (P less than 0.05) at a stroke work of 17.3 +/- 2.3 g.m. The value of dP/dt did not change significantly throughout. When LV function curves were generated by increasing cardiac output, the stroke work attained at an LVEDP of 10 cmH2O decreased with hemodilution from 23.9 +/- 3.5 to 20.8 +/- 3.9 g.m (NS). LV wall water content increased with hemodilution, from which it could be calculated that there was an 18.6% increase in LV mass. Thus, despite an increase in LV external girth demonstrated by LV circumferential gauges, it is possible that increased wall thickness due to the water gain resulted in little change or an actual decrease in LV end-diastolic volume. Thus, profound hemodilution can be attained with only slight depression of LV performance.

Anemia↗
PubMed1978

Clinical experience with intraaortic balloon pump support in 728 patients.

From November, 1968, through December, 1976, intraaortic balloon pump (IABP) circulatory support was used 747 times in 728 patients. Overall in-hospital survival was 413/747 (56.9%). Survival with IABP since 1974 has been 65% (286/440) compared to 24% (18/75) in 1968-1971 (P < 0.001). Two practical changes have been associated with this improvement: 1) broadened indications for, and earlier insertion of, IABP; and 2) more aggressive surgical treatment of the primary cardiac lesion. Cardiogenic shock or chronic ischemic ventricular failure accounted for 78.7% (59/75) of IABP in 1968-1971; during 1974-1976 only 26.4% (116/440) of IABP-supported patients were in these categories (P < 0.001). Since 1974, 58.2% (153/263) of IABP patients had an operative procedure following IABP insertion compared to 37.7% (23/611 prior to 1971 (P < 0.01). The major complication rate has remained unchanged at 8.5%. IABP-related mortality rate was 0.8% (6/728). Earlier, more liberal, use of IABP hemodynamic support has led to increased survival in a large number of patients with complications of acute myocardial ischemia. The low mortality associated with its use vindicates earlier institution of IABP support in cardiogenic shock.

Equipment Failure↗
PubMed1975

Effect of increased vascular pressure on lung fluid balance in unanesthetized sheep.

In 20 unanesthetized sheep, we measured lung lymph flow and lymph and plasma protein concentrations during steady-state base-line conditions and during steady-state elevations of pulmonary microvascular hydrostatic pressure (range 3 to 23 cm H2O). In every sheep there was a base-line lung lymph flow (average 5.7 +/- 2.5 (SD) ml/hour), demonstrating that net fluid filtration occurred. The base-line lymph-plasma total protein ratio averaged 0.69 +/- 0.05, indicating a high protein osmotic pressure in the interstitial fluid at the filtration site. Lymph flow increased and lymph protein concentration decreased approximately linearly whenever hydrostatic pressure rose. A new steady-state condition was reached in 1-2 hours. The difference in plasma-to-lymph protein osmotic pressure increased by half the hydrostatic pressure increment (50% negative feedback regulation). Extravascular lung water content, measured post-mortem, did not change significantly until microvascular hydrostatic pressure more than doubled, indicating a large safety factor that protects the lungs against fluid accumulation normally. The major contributions to the safety factor appeared to be a sensitive and efficient lymph pump coupled to a washout of interstitial protein. The fluid filtration coefficient, whose calculation required many assumptions, averaged 1.64 +/- 2.65 ml/(cm H2O times hour) in the base-line condition and did not change significantly over the pressure range studied.

Albumins↗
PubMed1975

Cannulation of the proximal aorta during long-term membrane lung perfusion.

Prolonged extracorporeal oxygenator support for acute respiratory failure is a clinical reality. Recent experience with 4 patients has demonstrated an advantage in delivery of saturated blood to the root of the aorta during venoarterial (VA) bypass. We have been able to perfuse the heart and bilateral cerebral hemispheres by advancing the tip of a large perfusion cannula to the aortic root from the common femoral artery. When the catheter did not pass beyond the transverse aortic arch, there was marked asymmetry of oxygenator perfusion, as determined by differential oxygen tension in right and left radial artery blood and by xenon-133 scans following isotope injection into the arterial return line. Long-term VA bypass lasting from 5 to 11 days resulted in long-term survival in 2 patients with post-traumatic gram-negative pneumonitis. The other patients, who had viral pneumonitis and post-transfusion respiratory failure, died after 9 and 11 days of membrane oxygenator support. No embolic lesions or arterial or valvular injuries were discovered at autopsy. This is a safe and useful method of providing oxygenated blood to the aortic root for equal distribution to the rest of the body.

Adult↗