Search PubMed⌕ Search

Biomedical subjects

W R Webb

Publications and source records attributed to W R Webb.

At least 235 records · Page 13Linked to original sources

The role of carbon dioxide in the development of pulmonary insufficiency.

The effects of carbon dioxide (PCO2 = 40 versus PCO2 = 20) on pulmonary function changes during 2 hours of hemorrhagic hypotension followed by resuscitation are evaluated in 21 dogs. Pulmonary hemodynamics, mechanics, gas exchange, functional residual capacity, and morphology are studied. In the preshock period, hypocapnia is associated with a decreased cardiac output, increased dead space, and increased alveolar-arterial (A-a) gradiant (room air). During the period of hypotension, all parameters in both groups changed similarly. After resuscitation, the A-a gradients in the two groups further widened. Following the return to control levels of normocapnia in all animals, the group which had been hypocapnic during the hypotensive episode continued to show increased shunting (20 versus 13 percent, p less than 0.05). These results correlated well with cinemicroscopic findings, which showed the normocapnic group to have less interstitial edema and better capillary flow.

Animals↗

Pulmonary complications in primary acquired hypogammaglobulinemia: surgical considerations.

With the discovery and routine use of antibiotics, a virtually new disease--primary acquired hypogammaglobulinemia--was recognized. More precise clinical, genetic, and laboratory endeavor has proved, in fact, that it is really one of a whole host of individual disease entities, all with the common feature of inadequate production and marshalling of gamma globulin to combat infection. Although the condition has been recognized in children's medicine for two decades, the survival of these early victims into adolescence and adulthood is now bringing them to the attention of surgeons as candidates for drainage or resection of suppurative disease of the lung, air tubes, and pleura. In fact a triad has emerged, with some of these patients having infectious disease in the lungs and sinuses associated with enlargement of the spleen when first seen. Often it is the radiologist who first suspects the diagnosis when he recognizes one or more features of this diagnostic triad. Three personal cases are presented together with a technique of management that appears successful. As with the recognition of any new disease, occult and subclinical presentations become more common as suspicion progresses, and ease of confirmation is afforded.

Adult↗

Cinemicroscopy of hyperacute pulmonary rejection.

Rejection processes were studied in xenografts and allotransplants of cat or dog lungs to dogs. Cinemicroscopy of the microcirculation in untreated animals showed almost immediate sludging, cellular aggregation, reduced vascular caliber, diminished blood flow, and rapid development of perivascular edema. The principal mechanisms of the extremely rapid xenograft rejection include capillary and arteriolar obstruction due to cellular aggregation. Pretreatment with heparin was virtually valueless, while methylprednisolone offered temporary protection.

Animals↗

Comparison of patients with coronary artery or valve disease: intraoperative differences in blood volume and observations of vasomotor response.

A review of 296 patients undergoing cardiac operations has shown that those with coronary artery disease have a blood volume deficit. The 148 patients with valve disease had a normal blood volume of 78 ml/kg (normal range, 68--88 ml/kg), while the 148 coronary artery disease had a blood volume of 69 ml/kg (p less than 0.001). Infusion of plasma prior to cardiopulmonary bypass as well as the total transfusion required afterward to maintain blood pressure indicated an important clinical difference in these two groups. Another finding was that the requirement for a drug to control blood pressure prior to use of cardiopulmonary bypass was greater in the coronary patients (p less than 0.01). Comparison of the requirement for a hypotensive agent before and after bypass showed a greater predictability in the valve group. This experience leads us to conclude that patients with coronary artery disease and angina not only have a low blood volume, but they also have a marked vasoactive lability which shows up in their hemodynamic response to the conduct of an operation and to anesthesia.

Blood Pressure↗

Ventilator-related extra-alveolar air in adults.

Extra-alveolar air (EAA) developed in 38 patients during mechanical ventilation. High ventilatory pressures and destructive lung disease predispose to EAA. Pneumoretroperitoneum and pneumoperitoneum are more common forms of ventilator-induced EAA in adults than generally realized; an associated pneumomediastinum was always identified when one of the two disorders above resulted from ventilation. Retroperitoneal air was located laterally along the liver and in the flanks, and changed little with change in patient position. Early detection of EAA may allow life-saving changes in therapy to be implemented.

Adolescent↗

Prophylactic digitalization for coronary artery bypass surgery.

One hundred and twenty patients undergoing aortocoronary bypass procedures were randomly placed into control and digitalized groups. All were initially in normal sinus rhythm and without evidence of congestive heart failure. Supraventricular arrhythmias occurred in 17 of 66 controls and in only three of 54 digitalized patients (P less than 0.01). There was no evidence of digitals toxicity. Based on this evidence we recommend prophylactic digitalization for patients having aortocoronary bypass operations.

Arrhythmias, Cardiac↗

Preliminary report: Evaluation of tissue ingrowth into experimental Replamineform vascular prostheses.

A new experimental arterial prosthesis has been developed by replacing the minimal surface microporous calcite structure of sea urchine spines. Prostheses having a 4 mm. inside diameter and a homogenous 15 to 20 mu porous network have been prepared in bioelectric polyurethane and segmented polyurethane. Ten prostheses were placed in the femoral and carotid arteries of dogs weighing 27 to 35 kilograms and were harvested at a time interval of 3 to 14 days to characterize the tissue ingrowth. Eight of the ten prostheses were widely patent at time of harvest, with tissue ingrowth evident as early as the third day and with complete fibroblastic and capillary penetration of the 1 mm. thick walls developed by the end of one week. By 2 weeks there was uniform formation of 50 to 100 mu well organized neointimal surfaces.

Animals↗