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Biomedical subjects

W C Shoemaker

Publications and source records attributed to W C Shoemaker.

At least 235 records · Page 13Linked to original sources
PubMed1978

Physiologic monitoring goals for the critically ill patient.

Definition of the appropriate therapeutic goals for physiologic monitoring of patients postoperatively was approached by analyzing more than 50,000 values of the 20 most commonly monitored variables in a series of 113 critically ill patients throughout their immediate postoperative course. In general, normal values were poor criteria for monitoring, since normal values were restored in an average of 75 per cent of the survivors and 76 per cent of the nonsurvivors for the five most frequently measured variables; that is, arterial pressure, heart rate, central venous pressure, wedge pressure and cardiac output. Moreover, an average of 56 per cent of the 20 most commonly monitored variables of nonsurvivors was restored to the normal range. Furthermore, 34 per cent of all the nonsurvivors' values were within the normal range; this was only 2.4 per cent less than the percentage of normal values for the survivors. The empirically determined median value of the survivors taken in the late stage during periods remote from therapy was found to be a better criterion for therapeutic goals for most variables, including blood flow, oxygen transport and most intravascular pressures. However, normal values were satisfactory for arterial pressure, peripheral resistance, pH, mixed venous oxygen tension and arterial carbon dioxide tension, largely because of the biphasic patterns of these variables.

Blood Chemical Analysis↗
PubMed1978

Comparison of cardiorespiratory effects of crystalline hemoglobin, whole blood, albumin, and Ringer's lactate in the resuscitation of hemorrhagic shock in dogs.

We studied the time course and interactions of hemodynamic, oxygen transport, colloid osmotic pressure (COP), and blood volume responses to 500 ml of crystalline hemoglobin (Hgb), 500 ml of whole blood (WB), 1,000 ml of Ringer's lactate (RL), and 500 ml of plasma protein fraction (PPF) given in random order to 12 mongrel dogs subjected to hemorrhagic shock by the standard Wiggers' technique. In general, hemodynamic and oxygen transport responses were greater and more prolonged after the colloids than after RL. These responses were related to concomitant improvement in blood volume and COP. Of the colloids, Hgb appeared to produce somewhat greater hemodynamic and oxygen transport changes. This was particularly evidenced by comparison of these responses when each fluid was the first agent used after the hemorrhage. By virtue of its capacity to increase COP and plasma volume and to carry oxygen, Hgb improved both the gross circulation and the tissue perfusion, as indicated by cardiovascular hemodynamics and bulk oxygen transport variables.

Animals↗
PubMed1978

Optimal hematocrit value in critically ill postoperative patients.

Failling hematocrit values are traditionally used to observe the course of active bleeding, since hematocrit values usually reflect acute blood losses. However, evidence from the literature suggests that, after volume replacement, some degree of normovolemic hemodilution may be desirable and that return to normal hematocrit values is not necessarily the appropriate goal of transfusion therapy. The optimal hematocrit value was defined empirically by three methods in a series of 94 critically ill postoperative patients. First, the mortality rates of postoperative patients were lowest with hematocrit values between 27 and 33 per cent. Second, mortality rates were examined when both hematocrit values and the important cardiorespiratory variables were reduced; significantly increased mortalties occurred when hematocrit values were less than an average of 32 per cent. Finally, oxygen availability and oxygen consumption increased significantly after whole blood and packed red cell transfusions were given when hematocrit values were less than 32 per cent but not above 33 per cent. When accurate blood volume measurements are not available, hematocrit values of 32 per cent are optimal; when volume therapy is indicated, blood may be given with hematocrit values less than 32 per cent, crystalloids or colloids are preferred with hematocrit values greater than 32 per cent.

Adult↗
PubMed1977

Relative hemodynamic effectiveness of whole blood and plasma expanders in burned patients.

In a series of nine fatally burned patients, hemodynamic and oxygen transport measurements were made before, during and after 56 administrations of 500 milliliters of whole blood or colloids and 1,000 milliliters of crystalloids. To enhance comparability, 38 of these studies were conducted at intervals on the same patient, the patient serving as his own control. The data indicate greater hemodynamic responses to colloids than to whole blood and greater responses to whole blood than to crystalloids when the latter was given at twice the volume as well as at four times the volume of the colloid. The data suggest that, in addition to replenishing salt and water, restoration of hemodynamic and oxygen transport variables may be accomplished by expansion of plasma volume with colloids and whole blood. Adequate nutrition is also needed for the increased metabolic needs of the burned patient. Without supplemental nutrition, high grade plasma proteins and tissue proteins may be expended as energy substrates; the lowering of plasma proteins tends to redistribute water from the plasma to the interstitial phase, which increases further the peripheral edema.

Blood Pressure↗
PubMed1976

Interorgan transport of amino acids in hemorrhagic shock.

Arterial concentrations and net organ metabolism of amino acids (AA), O2, CO2, H+, and glucose (Glc) were measured in two dogs before and during hemorrhage and after blood replacement. Shock caused increased splanchnic and decreased peripheral blood flow and O2 consumption. Po2 decreased more in hepatic venous than in mixed venous blood. pH fell in hemorrhage and increased with retransfusion. Increased liver output and arterial concentration of Glc were observed during hemorrhage. Differences between animals correlated with nutritional status. Blood concentrations of most AA showed little change during hemorrhage but increased after retransfusion. In contrast, arginine concentrations declined sharply. Peripheral output and hepatic uptake of most AA occurred during the control period. During shock, peripheral output and hepatic uptake of total AA and most individual AA declined progressively; after retransfusion peripheral uptake and hepatic output of many AA occurred. By contrast, peripheral output and hepatic uptake increased for alanine, glutamine, serine, phenylalanine, and tyrosine. After retransfusion net transport of some compounds occurred from periphery to liver; others, from liver to periphery. During shock, hepatic protein catabolism increased. and this catabolism, accompanied by decreased hepatic uptake (increased hepatic output), seemed the main cause of increased blood AA concentrations. Protein catabolism in peripheral tissue was not a cause of increased blood concentrations. Pathological changes in pH, Po2, and blood flow, occurred early in hemorrhage. In contrast, changes in AA movements and concentrations were within normal limits until late in shock.

Amino Acids↗
PubMed1976

Effects of transfusion on surviving and nonsurviving postoperative patients.

In the pretransfusion control period, generally, the cardiorespiratory values of the nonsurviving patients were worse than those of the surviving patients. Moreover, the responses of nonsurvivors to a standardized test of therapy generally were less than those of survivors. The increase in oxygen availability to the tissues after blood transfusion in nonsurvivors was almost as great as that of survivors, but the increase in oxygen consumed by nonsurvivors was only about one-half that of survivors. This is of particular importance in the critically ill patient, as reduction in oxygen transport represents a major physiopathologic problem in postoperative deaths.

Blood Pressure↗
PubMed1975

Cardiorespiratory responses to dextran 40. Hemodynamic and oxygen transport changes in normal subjects and critically ill patients.

Hemodynamic and oxygen transport were observed in 190 studies before and after administration of 500 ml dextran 40 in 12 normal, healthy subjects and 147 critically ill patients who were, or recently had been, in various degrees of shock. The major influence of dextran 40 was plasma expansion and hemodilution, which resulted in increased blood flow and blood volume. In general, the pressure-flow responses were greater in the ill patients than in the normal subjects. After dextran 40 infusion, oxygen transport increased in the critically ill patients, but not in the normal volunteers. Some of the effects of dextran 40 on oxygen transport in critically ill patients may be attributed to increased tissue perfusion from expansion of plasma volume, as well as to improved flow properties of blood in the microcirculation.

Acid-Base Equilibrium↗
PubMed1975

Survivor's and nonsurvivors' responses to dextran 40. Hemodynamic and oxygen transport changes in critically ill patients.

Cardiorespiratory effects of dextran 40 administration were measured and compared retrospectively in 74 surviving and 73 nonsurviving critically ill patients. In the preinfusion control period, the survivors had higher mean arterial pressures and blood flow with lesser blood volume deficits. Dextran significantly improved pressure, blood flow, blood volume, oxygen transport, and derived calculations in both groups, but the average cardiorespiratory responses to dextran were somewhat greater in nonsurvivors than in survivors, About two thirds of the patients responded to dextran with significantly increased oxygen consumption (P smaller than .05), suggesting that this agent improved oxygen transport by its rheologic effects on the microcirculation. The cardiorespiratory effects of dextran were slightly greater in the patients who ultimately died; nevertheless, the salutary cardiorespiratory response did not reverse the clinical course in nonsurvivors, whose perfusion defect apparently had reached irreversible proportions prior to the administration of the drug.

Acid-Base Equilibrium↗
PubMed1975

Cardiorespiratory response to a new isoquinoline derivative in critically III patients.

NC 7197, a new N-substituted tetrahydroisoquinoline derivative, was given in doses of 0.2 mg/kg body weight on 26 occasions to a series of 23 critically ill postoperative and posttraumatic patients who had been in moderate or severe degrees of shock. This agent was observed to improve pressure-flow and oxygen-transport variables, including increases in cardiac index, mean arterial pressure, central venous pressure, both left and right ventricular stroke work, central blood volume, systemic vascular resistance, oxygen availability, arteriovenous oxygen content difference, and oxygen consumption, and decreases in mean transit time and pulmonary vascular resistance. Previous studies on critically ill patients have suggested that these are the most commonly desired therapeutic actions for this type of patient. The agent has pronounced inotropic effect with minimal chronotropic effects, but with higher doses, chronotropic effects as well as alpha blocking effects may occur. The optimal effects may be obtained by adjusting the dose to an appropriate therapeutic range. It is concluded that, in the dose used, this agent produced both alpha and beta adrenergic actions in critically ill patients.

Adult↗
PubMed1975

Sequential changes in cerebral blood flow and distribution of flow within the brain during hemorrhagic shock.

Sequential changes in cerebral blood flow as well as in regional blood flow to the brain (brain stem, cerebellum, hypothalamus, white matter and grey matter) were measured in unanesthetized dogs subjected to gradual prolonged hemorrhage according to a protocol which stimulates the most commonly encountered type of clinical hemorrhagic shock. Microspheres labeled with five different radioactive isotopes were injected into a left atrial catheter at five different times: control, early hypotension (immediately after hemorrhage), late hypotension (just before reinfusion of the shed blood), as well as one and eight hours after reinfusion of the shed blood. Immediately after hemorrhage, the total cerebral blood flow decreased slightly, but increased when calculated as a percent of the cardiac output. In the late hypotensive, hypovolemic stage, there was decreased flow calculated both as percentages of cardiac output and absolute flow as compared with the initial response to hemorrhage. Immediately after reinfusion of the shed blood, there were further reductions of flow. Eight hours subsequently, flow rose to values slightly above control. The patterns of each region was almost identical to that of the total cerebral flow. Since each of the major regions of the brain are approximately equally affected, changes in the level of consciousness and other cerebral functions occurring with hypovolemic shock may reflect circulation of the white matter as well as that of the whole brain.

Animals↗
PubMed1975

Traumatic injuries to the duodenum: a report of 98 patients.

Data of 98 patients who had sustained traumatic injuries to the duodenum during a recent 7-year period is reviewed. The overall mortality was 23.5%; that of the blunt injury group was 35%, that of the penetrating injury group was 20%. However, after the establishment of a trauma unit, the mortality for duodenal injuries fell from 32% to 12%. Death from duodenal wounds may be reduced by earlier hospitalization, earlier diagnosis and consequently earlier surgical repair. Vigorous treatment of shock is essential. A specialized trauma unit with personnel experienced in the management of shock and trauma problems provides a better environment to carry out the preoperative and postoperative care of the acutely injured patient. Adequate surgical treatment of the blunt injury and missile injury of the duodenum should consist of the following procedures: 1) repair of the duodenal wall utilizing conventional techniques; 2) internal decompression of the repair by afferent jejunostomy; 3) efferent jejunostomy for postoperative feeding; 4) temporary gastrostomy; and 5) external drainage of the repair. In certain selected instances, the simple stab wound of the duodenum may be treated by conventional repair without decompression, but a loop of jujunum should be sutured over the repair to prevent delayed disruption. The majority of patients with injuries to the duodenum have associated organs injured which also require considered surgical judgment and action.

Adolescent↗
PubMed1975

Nutritional aspects of body water dislocations in postoperative and depleted patients.

Measurements of plasma volume with 125I human serum albumin, extracellular water (ECW) with 82Br-minus, and total body water (TBW) with 3-H2O were made on 16 postoperative patients, 15 depleted patients, and three control subjects. Intracellular water (ICW) was calculated as the difference between TBW and ECW. The observed findings for the series as a whole showed no change in blood volume, an increase of 3.7 I in ECW, and a decrease of 1.5 I in ICW as compared to predicted values based on current weight. Compared to predicted values based on normal (pre-illness) weight, the observed body weight decreased 16% and ICW decreased 22%; this suggests that body weight consistently under-estimates the extent of nutritional depletion. Severe depletion seen in postoperative patients indicates that frequently earlier use of total parenteral nutrition would be beneficial. ICW was found to be the most reliable single index of moderate or severe nutritional depletion; errors in estimating normal values interfere with its use in mild depletion. The ratio of ECW:TBW best reflects distortion of body water composition; it is largely independent of weight, and is a more sensitive index than absolute values of ICW. Repeat measurements of body composition were made on 9 patients given total parenteral nutrition for an average period of 18 days. On the average, there was an ECW decrease of 1.8 I, a body weight increase of 2 kg, and an ICW increase of 3.2 I after parenteral nutrition. The increased ICW represents the repletion of half of the average initial deficit of 6.1 The initial ratio of ECW:TBW of 0.58 was reduced to 0.50, returning it about three-quarters of the way to the expected normal value of 0.48. Intravenous administration of 5% glucose as sole source of calories may be a factor in distortion of body water compartments.

Adult↗
PubMed1975

Plasma expansion in surgical patients with high central venous pressure (CVP); the relationship of blood volume to hematocrit, CVP, pulmonary wedge pressure, and cardiorespiratory changes.

There was no correlation of blood volume measurements with central venous pressure (CVP) or hematocrit determinations and only minimal suggestive trends with wedge pressure in a large series of postoperative patients; the lack of correlations emphasize the unreliability of venous pressure and hematocrit determinations to predict blood volume alterations. To evaluate the physiological problems, to define optimal therapeutic goals, and to measure therapeutic effectiveness of volume loading with an oncotically active agent, we measured the hemodynamic and oxygen transport responses to 500 ml. of 5 percent albumin given over 1 hour in 22 patients with CVP greater than 15 cm. H2O. The patients were separated into two groups according to the CVP response to volume therapy. The CVP decreased in 14 (64 percent) of these patients (Group 1), but it increased slightly but not significantly in eight (36 percent) patients (Group 2). In Group 1 patients, there was increased flow, improvement of tissue perfusion as reflected by increased oxygen consumption, and augmentation of the ventricular function. In Group 2 there were slight increases in mean flow, mean pulmonary arterial pressure, and mean transit time and slightly decreased pulmonary vascular resistance; there was appreciable improvement in left ventricular function without significant deterioration of right ventricular function. The high initial central venous pressure is not a reliable index of either hypervolemia or cardiac failure in critically ill patients. It is concluded that a trial of volume loading with an oncotically active agent with frequent auscultation of the chest and careful observation of the CVP trends will give the maximum diagnostic as well as therapeutic information.

Adult↗
PubMed1975

Free-water clearance patterns as predictors and therapeutic guides in acute renal failure.

Sequential changes in renal function were studied in a series of 114 postoperative patients who developed acute renal failure. The loss of concentrating ability, manifest by a change from strongly negative free-water clearances to values near zero, occurred 24 to 48 hours before the onset of blood urea nitrogen (BUN) and creatinine elevations. In 15 patients a transient period of positive free-water clearance was documented just before these values approached zero. Criteria were proposed for early diagnosis of acute renal failure (ARF) based upon description of the temporal pattern of free-water clearance values. The loss of concentration ability occurred with decreased urinary Na+ concentration unless patients were given large amounts of saline solution prior to the development of ARF. This was followed by gradually increasing urinary Na+ concentrations. Changes in K+ concentrations were not significant until the late stage of renal failure. Recovery patterns in 46 of these patients who survived demonstrated an early return of negative free-water clearance followed by gradually decreasing BUN and serum creatinine values. During this period recovery of the ability of Na reabsorption and excretion of K+ was indicated by decreased urinary Na+ concentrations and increased urinary K+ concentrations.

Acute Kidney Injury↗
PubMed1975

Clinical determinants of survival from postoperative renal failure.

In a series of 114 consecutive patients with acute renal failure, the over-all mortality rate was 60 per cent; 62 per cent of the patients had a documented episode of hypotension just prior to the development of acute renal failure. In 11 patients, a second episode of renal failure developed following recovery from the initial episode of acute renal failure; all of these patients died. The urine output rate during the course of acute renal failure was inversely related to the mortality rate in the series as a whole. The mean duration of acute renal failure in survivors of the present series was 11.0 plus or minus 1.4 days. Complications of renal failure in the order of their frequency included hemorrhagic hypotension, sepsis, sepsis with hypotension and consumption coagulopathies; only 12 per cent had no complications. Only six of 51 patients whose clinical course was complicated by sepsis with or without an episode of hypotension survived. By contrast, 30 of 53 patients who had hemorrhagic hypotension without sepsis survived. The date suggest that although acute renal failure has a high mortality rate, it is a benign disease that is potentially reversible. Regardless of age and sex, renal functional recovery will take place if the patient is maintained in good physiologic condition long enough without a continued stress, such as sepsis, hypotension or hypovolemia, all of which prolong renal ischemia. During the course of renal failure, extreme care is essential to maintain adequate circulating volume without extracellular fluid overload; a second hemodynamic insult may result in serious damage to the regenerating renal tubules. We conclude that early recognition of acute renal failure, aggressive management of sepsis, careful titration of fluid and electrolyte therapy, meticulous monitoring, maintenance of the circulation and judicious utilization of dialysis will aid in reduction of mortality in these critically ill patients.

Acute Kidney Injury↗
PubMed1975

The correlation of sequential changes in the distribution of pulmonary blood flow in hemorrhagic shock with the histopathologic anatomy.

Histopathologic changes were described and correlated with hemodynamic changes in a series of farm-reared dogs by a preparation and a protocol which were shown to simulate closely physiologic events in clinical hemorrhagic shock; neither anesthesia nor thoracotomy was used and flush solutions for catheters were strictly limited; a series of sham-treated controls was used for comparison. Five different isotopes were used to label microspheres to measure blood flow sequentially at the tissue level at various stages of the shock protocol. At death, multiple tissue sections were taken relative to six parallel segments of the lung arranged according to dependency so that correlations of structure and function might be related to the influence of gravity. The degrees of severity of atelectasis, hemorrhage, edema, congestion, inflammation, and hyperaeration were evaluated by rating scales. Tissues from the most dependent areas had a higher incidence and greater severity of histologic lesions. Tissues with mild histologic rating tended to have lower percentages of flow after hemorrhage, but normal or increased flow after reinfusion. The severely damaged tissue received greater than average flow throughout. Tissues with severe atelectasis paralleled the course of those with a high over-all severe pathologic rating. Tissues with severe inflammation had less blood flow in the control period, increased flow in Stages B1 and B2 and a subsequent return to control values. Those with severe edema had reduced flow in Stages B2 and B3, but high flows after reinfusion.

Animals↗