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Biomedical subjects

J H Duff

Publications and source records attributed to J H Duff.

At least 55 records · Page 3Linked to original sources
PubMed1978

Pulmonary hypertension in sepsis: measurement by the pulmonary arterial diastolic-pulmonary wedge pressure gradient and the influence of passive and active factors.

To examine the relative roles of passive factors (flow; filling pressures of left side of heart) and active factors (acidosis; arterial unsaturation) in the genesis of pulmonary hypertension when associated with sepsis, 37 patients with sepsis and 24 patients without sepsis were examined. Pulmonary hypertension was measured by the pulmonary arterial diastolic-pulmonary wedge pressure gradient (PAd-PWP gradient) and correlated reasonably with a standard formula for calculated resistance ([PA--PWP]/CI, where PA is mean pulmonary artery pressure and CI is cardiac index). In 22 of 37 patients, sepsis was associated with a significant degree of resistance to flow in the pulmonary circulation, as measured by the PAd-PWP gradient: and the higher the PAd--PWP gradient, the greater the likelihood of early death. None of the examined passive or active factors appeared to be adequate to explain pulmonary hypertension when present. By the use of previously derived formulae to estimate the compliance of the elastic pulmonary arteries, factors affecting this part of the pulmonary microcirculation could not be held accountable for apparent pulmonary hypertension. Therefore, the presence of pulmonary hypertension in sepis appears to be an active, rather than a passive, phenomenon and unrelated to arterial oxygen saturation or acid-base imbalance. Although the exact cause is unknown, pulmonary hypertension in sepis is associated with a high mortality and may be clinically followed by measurement of the PAd-PWP gradient.

Bacterial Infections↗
PubMed1977

Cardiovascular and metabolic changes in shock and sepsis. Review fo changing concepts.

The commonly accepted sequence of low blood flow, tissue hypoxia, lacticacidosis and death does not apply to all patients dying from shock. The hyperdynamic circulation characteristic of severe sepsis is not likely due to peripheral arteriovenous shunts, since in skeletal muscle at least, capillary blood flow is increased and varies directly with cardiac index. A hyperdynamic circulatory state is seen in many patients with sepsis and may be related to metabolic changes rather than changes in oxygen transport. Skeletal muscle capillary blood flow is increased in fasting normal subjects and septic postoperative patients, both of whom are catabolic. Therefore, elevated blood flow, which is characteristic of severe sepsis, may be a response to or necessary for the catabolism of body protein required for energy production. Profound metabolic abnormalities resulting in rapid catabolism may be responsible for the demise of the septic patient. If this concept of sepsis is accepted, it follows that treatment which heretofore has been aimed at increasing blood flow and blood pressure should be redirected to therapy which provides energy substrates and alters hormonal patterns to favor anabolism.

Acidosis↗
PubMed1976

Delayed primary closure in colon operations.

Secondary closure of incisions by tape is a simple, safe procedure. In a retrospective series of 179 contaminated surgical wounds (incisions for colon operations) delayed wound closure resulted in a lower incidence of wound infection (5.8%) than did primary closure of similar wounds (11.8%). Although wounds left open do become infected, the acute swelling and systemic signs typical of an infection in a closed wound never develop. Delayed closure facilitated wound healing in hospital: only 3.8% of patients thus treated left hospital with open wounds, but 9.5% of patients whose wounds were closed primarily left hospital with wounds that were partially or completely open.

Anti-Bacterial Agents↗
PubMed1976

Acute perforation of the colon.

Acute perforation of the colon causes fecal peritonitis, which is associated with high rates of morbidity and mortality. Findings in 78 patients with perforation of the colon showed that the commonest causative condition was diverticulitis (in 42%) and that the commonest site was the sigmoid colon (in 65%). The overall mortality in this series was 49%, most of the deaths being due to peritonitis; the extent of anatomic spread of peritonitis was a major factor. The form of treatment was also a factor in mortality: mortality was lowest in patients treated by diversionary colostomy (only 38%) and highest in those treated by exteriorization of perforation (71%) and in those not treated operatively (71%). With respect to postoperative complications in patients who underwent operation, wound infection and pulmonary abnormalities each occurred in 50%. This review suggests that current methods of management of patients with perforation of the colon are less than satisfactory.

Colonic Diseases↗
PubMed1976

Arterial plasma amino acids in patients with serious postoperative infection and in patients with major fractures.

Arterial plasma amino acids were measured in 27 patients with serious septic complications after operation, 15 patients following reduction of femoral shaft fractures and nine control patients on the first and third days following uneventful major abdominal surgery. Amino acid concentrations in the controls were similar to those which have been reported during early starvation. The amino acid patterns seen in all groups did not resemble that previously observed following glucocorticoid administration. In the patients with infection, mean phenylalanine concentration (108.0 +/- 46.9 mumoles per liter) was significantly greater than in the controls on the first (p greater than 0.001) or third (p less than 0.001) postoperative days. Four of the septic patients with hyperphenylalaninemia also had elevated arterial methionine concentrations. These observations suggest that many of the patients with sepsis had seriously impaired liver metabolism. In patients with fractures, the concentrations of ornithine (p less than 0.001), taurine (p less than 0.05), and aspartic acid (p less than 0.05) were lower than in controls. No other significant differences of amino acid concentrations were observed. It is difficult to relate these differences to a specific metabolic abnormality.

Abdomen, Acute↗
PubMed1975

Pulmonary edema in patients with sepsis.

Fifteen critically ill patients with sepsis, 12 of whom had significant pulmonary dysfunction develop, were investigated with regard to changes in pulmonary capillary pressure, in serum oncotic pressure and on roentgenograms of the chest. It could not be shown that the pulmonary edema, which is a major characteristic of the septic lung lesion, was due to changes only in oncotic and hydrostatic pressures. Nor was there evidence that increased capillary permeability was the sole explanation of the edema. A significant relationship was found which consisted of increasing severity of the lung lesion, decreasing serum oncotic pressure and increasing pulmonary pressure. When patients with sepsis require resuscitation with fluids, the administration of moderate amounts of albumin along with monitoring of pulmonary capillary pressure appears to be a rational approach to therapy.

Bacterial Infections↗
PubMed1975

Capillary muscle blood flow in human sepsis.

Tissue perfusion was determined by cardiac index (Cl) and skeletal muscle capillary blood flow (MBF), and arteriovenous oxygen difference (AVD) and oxygen uptake were compared in seven patients with severe spesis and eight nonseptic patients. Skeletal capillary muscle blood flow also was measured before and after a 2 day fast in 14 normal volunteers. In both septic and nonseptic patients, MBF varied directly with Cl. The average muscle blood flow was greater in septic than in nonseptic patients and, in addition, was greater per unit Cl. AVD in septic patients was narrower than in nonseptic patients. Septic patients with an AVD of less than 4 ml. of O2 had markedly higher MBF and Cl than did septic patients with an AVD greater than 4 ml. of O2. Fasting normal volunteers who, like the septic patients, would be catabolic had a significant increase in MBF during the fast. Although peripheral shunts are not ruled out ans an explanation of the hyperdynamic circulation in sepsis, the evidence is against their existence, at least in skeletal muscle, since capillary flow increases in direct proportion to cardiac output. If capillary flow is increased in fact in sepsis, then flow like blood pressure becomes less of a critical factor in explaining the demise of the septic patient. It might be postulated that the increased capillary flow seen in sepsis is secondary to the mobilization of amino acids from the body cell mass for gluconeogenesis and energy.

Adult↗