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Biomedical subjects

W C Shoemaker

Publications and source records attributed to W C Shoemaker.

At least 37 records · Page 2Linked to original sources

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

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

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

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

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

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

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

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

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

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

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

The influence of parenteral nutrition on the course of acute renal failure.

The influence of hypertonic glucose with and without added amino acids was studied in 129 consecutive postoperative patients with acute renal failure. The addition of amino acids was associated with lower mortality and morbidity rates in the patients who received dialysis as well as in those who did not. There was no significant differences in the blood urea nitrogen levels of the two groups. The incidence of hyperkalemia and the rise in plasma osmolality were less in the group given adequate calories and amino acids.

Acute Kidney Injury

Experience with a multidisciplinary critical care center in a community hospital.

A multidisciplinary intensive care unit has been developed in a community hospital by planning techniques which are still not common in the hospital development environment. The resulting Acute Care Center has special attributes, especially in ongoing professional educational and consultation support, in continuous physician staffing aroung the clock, in equipment and in operational policies. The net result appears to be the provision of a higher standard of patient care, a lower mortality rate for the critically ill patient, and various cost benefits. The concepts and policies involved are being met with increasing acceptance in the local medical community.

Adolescent