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Biomedical subjects

G W Machiedo

Publications and source records attributed to G W Machiedo.

At least 55 records · Page 3Linked to original sources
PubMed1982

Hemodynamic effects of prolonged infusion of prostaglandin E1 (PGE1) after hemorrhagic shock.

Although one-hour infusions of prostaglandin E1 to animals suffering from hemorrhagic shock have proved beneficial, there is question as to whether the improved hemodynamics can be sustained over a longer infusion time. Following reinfusion of shed blood, an infusion of PGE1 at a dose of 1 microgram/kg/minute showed a significant elevation in cardiac output and left ventricular stroke work and a decrease in systemic vascular resistance when compared to animals receiving only an equal volume of normal saline. There was no diminution in the hemodynamic activity of the drug over the entire infusion period. These data indicate that the drug might be appropriate for hemodynamic support in the clinical situation, where infusion times of greater than one hour are often necessary.

Alprostadil↗
PubMed1982

Histologic and hemodynamic effects of prostacyclin and prostaglandin E1 following oleic acid infusion.

The hemodynamic and histologic effects of exogenous prostacyclin (PGI2) and prostaglandin E1 (PGE1) on oleic acid-induced acute respiratory failure were investigated. Adult mongrel dogs infused with oleic acid were treated with saline solution, PGE1, and PGI2. Significantly lowered blood pressure, systemic and pulmonary vascular resistance, and arteriovenous oxygen difference and preservation of preoleic cardiac output were observed in the pGI2 group. Compared with the saline group, only the arteriovenous oxygen difference was improved with PGE1. Light microscopy revealed acute edema and inflammation in the saline- and PGE1-treated lungs. Histologic specimens in the PGI2 group were normal.

Animals↗
PubMed1982

Penetrating injuries to the colon.

In planning the management of a colonic injury, several factors must be taken into account, including the age of the patient, the cause of the wound, the time lapse from injury to operation, area and the type of wound, the amount of fecal soilage, and the number and extent of associated injuries. For extensive wounds with associated injuries, fecal contamination of the abdomen, or delay from injury to treatment, a two-stage procedure is preferred. Primary closure or primary resection is the preferred treatment for right colon injuries, depending on the severity of the injury. Resection and anastomosis should not be performed in the left colon without a diverting colostomy. Exteriorization is a satisfactory procedure for major colon injury; however, exteriorization and repair have a higher associated complication rate than exteriorization alone. Primary repair is a safe and acceptable procedure, irrespective of the site of injury. Indications for primary repair may, in the future, be expanded to include those wounds presently being treated by exteriorization.

Adolescent↗
PubMed1981

Prostacyclin (epoprostenol): its effect on canine splanchnic blood flow during hemorrhagic shock.

Prostacyclin (epoprostenol, prostaglandin I2) is a vasodilator of the splanchnic circulation during normotensive states. To confirm the persistence of its effects after hemorrhagic shock, six anesthetized, previously splenectomized, adult mongrel dogs were subjected to hemorrhagic shock using a modified Wigger's technique in which a mean arterial pressure of 30 mm Hg was maintained until 25% of the shed blood spontaneously returned. The animals were randomly resuscitated with normal saline solution or a similar volume of saline solution containing prostacyclin. Organ blood flow was calculated by measuring the distribution of radioactively tagged microspheres. During shock, blood flows to the liver, small intestine, pancreas, and carcass were reduced. During a 60-minute infusion, prostacyclin selectively caused a significant increase in hepatic arterial blood flow. This improvement in arterial blood flow may prove beneficial in the clinical management of hemorrhagic shock.

Animals↗
PubMed1981

Patterns of mortality in a surgical intensive care unit.

Mortalities in a surgical intensive care unit during a three year period were reviewed. The over-all mortality was 8.2 per cent. Sixty-four per cent of the deaths followed nontraumatic surgical illness and 36 per cent followed trauma. Eighty-one per cent of patients died as a direct result of traumatic injuries, while only 19 per cent died of sepsis or multiple organ failure. On the other hand, 62 per cent of the nontrauma related deaths were a consequence of sepsis or multiple organ failure. Further research into cellular support is needed to reverse the problem of sepsis related organ failure.

Adult↗
PubMed1981

The effect of ATP-MgCl2 infusion on hepatic cell permeability and metabolism after hemorrhagic shock.

The ability of exogenous ATP-MgCl2 to reverse the inhibition of ATP-dependent intracellular reactions by hemorrhagic shock was studied. Levels of ornithine in the postperfusion fluid were lower in animals receiving ATP-MgCl2 than in placebo-treated control animals (338.6 +/- 167.0 versus 692.1 +/- 67.2 mumol). Arginine levels were higher (399.1 +/- 130.1 versus 34.3 +/- 59.1 mumol) in ATP-MgCl2-treated animals. Ability of in vitro ATP to enter the cell and inhibit lactate formation (Crabtree effect) was significantly less in those animals receiving in vivo ATP-MgCl2 (81.4 +/- 11.1% versus 57.7 +/- 10.1%). Glutamate levels were not decreased by shock but were significantly increased by treatment with ATP-MgCl2 compared to placebo (190.5 +/- 48.8 versus 122.6 +/- 36.3 mumol). These data indicate that exogenously administered ATP-MgCl2 can reverse the inhibition of ornithine metabolism and the changes in lactate inhibition seen in hemorrhagic shock. These are both intracellular ATP-dependent reactions.

Adenosine Triphosphate↗
PubMed1981

Management of nonpenetrating stab and gunshot wounds of the chest.

Records of 102 patients with gunshot and stab wounds to the chest but with normal roentgenogram of the chest upon admission were reviewed. There were no delayed hemothoraces or pneumothoraces. The three complications probably resulted from admission to the hospital and would not have occurred if the patients had maintained their normal daily activities. The cost of these admissions was $104,319, and no benefit resulted from them. A significant number of routine studies were done with an extremely low yield. These patients need not be admitted to the hospital unless there is some other compelling clinical factor.

Adolescent↗
PubMed1981

The effect of pH of resuscitative fluids in treatment of severe hemorrhagic shock.

Commercially available Ringer's lactate solution has a pH of approximately 6.5. In a situation such as shock, which is normally accompanied by a metabolic acidosis, this additional acid load could have an adverse effect on resuscitation when massive amounts of fluid are required. We prepared a similar solution with a pH of 7.4 and compared the two solutions. Fourteen dogs were shocked according to a Wiggers' hemorrhagic shock model. Six dogs (43%) died during shock, 8 dogs survived the model, 4 were resuscitated over a 150-minute observation period to a pulmonary capillary wedge pressure (PCWP) of 8-12 mmHg with Ringer's lactate with a pH of 7.4. The cardiac output, lactate levels, amount of fluid required to maintain the PCWP, and arterial and mixed venous pH were measured at 30, 60, 90, 120, and 150 minutes. No significant differences were found except for occasionally higher arterial pH values in the group treated with Ringer's lactate with a pH of 7.4. There was no difference between the groups in any measurement at the end of the observation period or in survival. All dogs died within 12 hours of the end of the shock period. Our data indicate that the somewhat acidic pH of standard Ringer's lactate does not adversely affect the adequacy of resuscitation. There is no advantage to using Ringer's lactate with a pH of 7.4.

Animals↗
PubMed1980

Multiple perforations of colon after compressed air injury.

Multiple perforations of the colon after compressed air injury occurred. The initial perforation did not become manifest until five days after the injury. This was repaired at laparotomy and a proximal colostomy was performed. Ten days after the first operation, a second laparotomy showed a second larger tear at the level of the peritoneal reflection. After a Hartmann procedure, the patient did well and was discharged from the hospital. This case emphasizes the need for repeated exploratory surgery of the abdomen if the initial postoperative course is not uneventful since full-thickness perforation of the colon may be delayed in its presentation.

Accidents, Occupational↗
PubMed1980

The hemodynamic effects of prostaglandin E1 (PGE1) in acute hypoxic respiratory failure.

The hemodynamic effect of prostaglandin E1 (PGE1) on acute respiratory failure is investigated. Eight adult mongrel dogs were subjected to oleic acid-induced acute respiratory failure. Four dogs received PGE1 intravenously one hour after oleic acid injection, and four received an equal volume of saline. Cardiac output, arterial PO2 and alveolar-arterial oxygen difference decreased significantly in the saline-treated animals, and systemic vascular resistance increased. These parameters were maintained in the PGE1 group, and stroke volume and arterial-venous oxygen difference were improved. Pulmonary vascular resistance increased in both groups. This beneficial effect of PGE1 in acute respiratory failure may be related to maintenance of hemodynamics and pulmonary gas exchange and to improved tissue oxygenation.

Acute Disease↗
PubMed1980

Colostomy closure following trauma.

All patients undergoing a post-traumatic colostomy closure at the New Jersey Medical School Affiliated Hospitals from 1974 to 1978 were studied for the effect of timing and technique of colostomy closure on postoperative complications. Analysis showed that patients in whom the colostomy was closed between six weeks and three months had a significantly shorter operating time when compared with those operated upon less than six weeks after formation of the colostomy. They also had a lower infection rate, shorter time to intestinal function and shorter postoperative hospital stay. Patients undergoing closure of a loop colostomy were analyzed for the technique of closure. Those patients undergoing a simple loop closure had a significantly shorter length of operation time, lower infection rate and shorter time to return of intestinal function. The safest time to close a colostomy created for trauma is between six weeks and three months. The reason for the increased complication rate in the early group is technical difficulty due to incomplete resolution of the edema and inflammatory reaction. Every effort should be made to close a loop colostomy without resorting to resection.

Abdominal Injuries↗
PubMed1979

Comparison of corticosteroids and prostaglandins in treatment of hemorrhagic shock.

The hemodynamic and microcirculatory effects of prostaglandin E1 and methylprednisolone sodium succinate were compared in a standard canine shock model. Prostaglandin significantly increased cardiac output and decreased total peripheral resistance when compared to control animals while steroids did not. There was no significant effect upon heart rate or arterial pressure by either drug. Methylprednisolone sodium succinate significantly increased arterial pH at the conclusion of the experiment and showed directional improvement in venous lactate and proteolytic activity. Prostaglandin significantly increased length of survival compared to both steroid and control infusion. It is concluded that prostaglandin and steroid have different hemodynamic effects in shock, that steroid protects microcirculatory flow more efficiently and that the prolongation of survival seen with prostaglandin infusion is not entirely due to its hemodynamic or lysosomal stabilizing effects.

Animals↗
PubMed1978

Effect of prostaglandin E1 and steroid combination in the treatment of hemorrhagic shock.

Prostaglandin E1 and methylprednisolone sodium succinate were administered simultaneously after shock in an intact canine hemorrhagic shock model and compared to treatment with each agent singly and with a 60 cc saline infusion. A detrimental effect of the prostaglandin E1/steroid combination was evidenced by decreased heart rate, mean arterial and central venous pressures, cardiac output, and arterial pH, and increased venous lactate. Survival was poor after the combined regimen. These changes may be related to vasodilation in the peripheral vascular system, causing pooling of blood. Lysosomal membranes were stabilized in spite of prolonged hypoperfusion.

Animals↗