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Biomedical subjects

W C Shoemaker

Publications and source records attributed to W C Shoemaker.

At least 163 records · Page 9Linked to original sources
PubMed1984

Splenic salvage using biologic glue.

Fibrin sealant (FS) is a biologic adhesive containing highly concentrated human fibrinogen that is effective in the face-to-face sealing of tissues, and in establishing hemostasis. We evaluated FS in 32 experimentally produced splenic injuries in six adult mongrel dogs. Complete hemostasis was achieved in all animals prior to closure. The dogs were reexplored postoperatively at intervals varying from four hours to six weeks (mean +/- SD, 21 +/- 20 days). When the dogs were killed, there was no gross evidence of splenic disruption or recurrent bleeding; all of the spleens had developed well-healed capsules. Histologic examination demonstrated a regenerated fibrous capsule extending over the superficial injuries as well as into the deep injuries, without significant inflammatory response. We conclude the following: that FS provides adequate hemostatic control of superficial and deep splenic injuries, FS has good systemic and local compatibility, it can be applied to bleeding parenchymal wounds, it reduces the need for parenchymal sutures that may be traumatic, and it promotes splenic wound healing.

Animals↗
PubMed1984

Diagnosis of major peripheral arterial trauma by transcutaneous oxygen monitoring.

During a 6 month period, 36 consecutive suspected major peripheral arterial injuries in 33 patients were evaluated by clinical examination and Doppler signal. Thirty-three of these injuries were also evaluated using portable transcutaneous oxygen monitors. Of the 12 confirmed arterial injuries, 2 had normal Doppler-derived blood pressures and significantly decreased transcutaneous oxygen tensions. The transcutaneous oxygen values in traumatized limbs with arterial injury were significantly lower than in traumatized limbs without arterial injury (34 +/- 6 versus 58 +/- 3, p less than 0.01). The ratio of the injured limb transcutaneous oxygen tension to the uninjured contralateral limb transcutaneous oxygen tension was also significantly lower in the group with arterial injury than in the group without arterial injury (0.72 +/- 0.08 versus 1.12 +/- 0.05, p less than 0.01). The overall sensitivity and specificity of the diagnosis of major peripheral arterial injury by a bilateral transcutaneous oxygen ratio less than 0.90 was 80 percent and 91 percent, respectively. In addition, transcutaneous oxygen monitoring helped quantify tissue perfusion in limbs with decreased neurologic function and Doppler-derived blood pressure. The results suggest that transcutaneous oxygen monitoring is a valuable, noninvasive adjunctive method for the diagnosis of major peripheral arterial trauma.

Adolescent↗
PubMed1984

Method for intraoperative assessment of organ perfusion and viability using a miniature oxygen sensor.

A specially designed miniaturized Clark polarographic electrode was used to measure organ surface oxygen tension during surgical operations in 10 patients as a means of determining tissue perfusion and viability. When applied to organ surfaces, the sensor noninvasively provides real-time assessment of tissue PO2. Values obtained are dependent on both arterial PO2 and local blood flow and therefore may be used to quantitatively assess local oxygen delivery (perfusion). Measured values may be compared with arterial PO2 or to areas of certain normal perfusion on the same organ to better define the adequacy of local oxygen transport. Tissue temperature is independently measured and may be used to assess the metabolic activity of the tissue monitored. Organ surface oximetry using the miniature PO2 sensor is a practical and repeatable method for the intraoperative assessment of organ perfusion and viability.

Adenocarcinoma↗
PubMed1984

Assessment of peripheral vascular disease by postocclusive transcutaneous oxygen recovery time.

A method for assessing peripheral vascular disease (PVD) was developed from the pattern of transcutaneous oxygen (PtcO2) changes after temporary limb ischemia induced by pneumatic blood pressure cuff occlusion. The transcutaneous oxygen recovery half-time (TORT) was defined as the time required to recover half of the decrease in the limb/chest PtcO2 ratio produced by temporary limb ischemia. TORT was examined in subjects with and without significant PVD. Patients who underwent operative therapy for symptomatic PVD were studied before and after operation. Comparison was also made of the values of patients in whom therapy was successful in resolving symptoms vs. those in whom it was not. TORT was found to improve the diagnostic accuracy of PtcO2 measurements to differentiate normal vs. PVD limbs and successful vs. unsuccessful results of therapy. Normal subjects uniformly had TORT values less than or equal to 1.5 minutes at both calf and foot positions; limbs with symptomatic PVD consistently had TORT values that were significantly longer in duration (p less than 0.001). Limbs with PVD that received successful therapy had a significant improvement in calf and foot TORT values after surgery (p less than 0.01); postoperative values were usually slightly longer than those of normal subjects, probably reflecting some residual disease. Postoperatively, limbs with PVD that had received unsuccessful therapy either had only slight improvement or worsening of their TORT values, which were significantly greater than the TORT values of limbs that received successful therapy (p less than 0.001). We conclude that measurement of postocclusive TORT is a reliable method for diagnosing PVD and for quantitatively evaluating residual disease after operative therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Reliability of clinical monitoring to assess blood volume in critically ill patients.

Blood volumes measured by indicator dilution method in over 1500 instances of critically ill patients of various etiologies and at various times throughout their critical illness were compared with the values of concomitantly measured mean arterial pressure (MAP), CVP, pulmonary arterial wedge pressure (WP), Hct, and cardiac output. During resuscitation from hypovolemic shock, the patients' blood volumes and the monitored variables were significantly altered. However, there were poor correlations between the extent of blood volume changes and these variables during resuscitation as well as throughout the critical illness, irrespective of the etiologic type or stage of shock. With administration of a fluid load, blood volume and values of the commonly monitored variables improved appropriately, but the correlation coefficients, in general, were not good. The data suggest that the commonly monitored variables, in and of themselves, do not reflect adequately the blood volume status in critically ill patients.

Blood Pressure↗
PubMed1984

Spontaneous colonic perforation secondary to cytomegalovirus in a patient with acquired immune deficiency syndrome.

We report a case of spontaneous perforation of the transverse colon due to multiple ulcerations infected with cytomegalovirus (CMV) in a patient suffering from acquired immune deficiency syndrome (AIDS). The authors recommend a thorough clinical and laboratory search (including tissue diagnosis, when possible) for evidence of CMV infection in immunosuppressed patients with new or poorly healing GI ulcerations, who are otherwise at risk for CMV infection, e.g., patients with AIDS. When performing surgery on AIDS patients, operating room protocol should be identical to that used for hepatitis B virus patients.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Cardiorespiratory responses to fluid administration in peritonitis.

Intravascular volume expansion was studied in 59 critically ill patients with a wide variety of sepsis and in a small group of 12 patients with peritonitis; either 500 ml of 5% albumin solution or 2 units of packed red blood cells were given over a 60-min period. During the 2-h period after volume loading, significant increases in mean arterial pressure (MAP), pulmonary capillary wedge pressure (WP), central venous pressure (CVP), and oxygen consumption (VO2) were observed. One hour after fluid administration MAP had risen from 72 +/- 16 (SD) at baseline to 78 +/- 17 mm Hg (p less than .01), WP from 9 +/- 5 to 16 +/- 7 mm Hg (p less than .05), CVP from 7 +/- 4 to 9 +/- 4 mm Hg (p less than .05) and VO2 from 132 +/- 19 to 148 +/- 31 ml/min X m2 (p less than .01). Improvement in VO2 after volume loading is consistent with the concept that circulatory problems in sepsis result in less VO2 than is needed and that intravascular volume expansion in normovolemic septic patients may improve peripheral perfusion as measured by oxygen uptake.

Adult↗
PubMed1984

Oxygen transport and utilization in hyperoxia and hypoxia: relation of conjunctival and transcutaneous oxygen tensions to hemodynamic and oxygen transport variables.

A device to measure surface oxygen tension of the palpebral conjunctiva (PcjO2) was developed and tested in 12 mongrel dogs subjected to normoxia, hyperoxia, and hypoxia. Intravascular pressure, hemodynamic, and bulk oxygen transport variables were measured simultaneously with PcjO2 and transcutaneous O2 (PtcO2) and CO2 (PtcCO2). PcjO2 closely paralleled PaO2 as the fractional inspired O2 concentration was changed from 0.21 up to 1.0 and down to 0.05; the correlation coefficient, r, was 0.95 for 305 data sets. During hyperoxia there were no significant hemodynamic or bulk O2 transport changes, but during hypoxia, the cardiac output and O2 extraction increased while PaO2, PtcO2 and PcjO2 fell; O2 delivery and O2 consumption were maintained until just before death.

Animals↗
PubMed1984

Effect of hemorrhagic shock on conjunctival and transcutaneous oxygen tensions in relation to hemodynamic and oxygen transport changes.

To evaluate possible physiologic mechanisms in hemorrhagic shock, sequential hemodynamics, O2 transport, conjunctival O2 (PcjO2), transcutaneous blood gases (PtcO2, PtcCO2), and core and conjunctival temperature (Tcore, Tcj) were measured during a control period, after hemorrhage, after reinfusion of the shed blood, and subsequently during terminal normovolemic shock in eight anesthetized dogs. The PtcO2 sensor requires surface heating to 44 degrees or 45 degrees C, whereas the PcjO2 sensor measures surface temperature but does not heat the tissue, thus avoiding heat-induced artifacts. Shortly after onset of hemorrhage, hemodynamic variables, bulk O2 transport, and tissue O2 tensions decreased abruptly. Prolongation of hemorrhage further deteriorated these variables. Reinfusion of the shed blood returned all values except PcjO2 to the normal range. In the terminal stage, all variables except PaO2 again deteriorated; decreased O2 transport impaired oxygen consumption, which in turn reduced both central and peripheral heat production. Lowered oxygen consumption, Tcore and Tcj reflect decreases in total-body and local tissue metabolism. These data are consistent with the concept that tissue O2 tension represents the balance between O2 supply and O2 demand and thus reflects overall O2 metabolism, which may be rate-limited by circulatory deficiencies.

Animals↗
PubMed1984

Perioperative transcutaneous O2 monitoring in the management of major peripheral arterial trauma.

The present report discusses the use of transcutaneous oxygen (PtcO2) monitoring in the perioperative management of a patient with two major peripheral arterial occlusions secondary to blunt trauma, during the performance of an external iliac artery thrombectomy and distal popliteal artery embolectomy. The injured limb PtcO2 was extremely low before surgery, but then increased to levels equal to and above contralateral limb PtcO2 a full 1 hour before skin closure. The injured limb PtcO2 correlated well with contralateral limb PtcO2 values after restoration of normal blood flow (r = 0.97). The ratio of injured limb PtcO2 to contralateral limb PtcO2 may be used to quantify the severity of arterial compromise in limb trauma and the adequacy of its treatment.

Adult↗
PubMed1984

Sequential cardiorespiratory patterns associated with outcome in septic shock.

Sequential hemodynamic and oxygen transport monitoring was performed in 33 patients with septic shock to define physiologic patterns associated with outcome. Measurements taken over a 24-hour period prior to the hypotensive crisis, defined as the lowest initial mean arterial pressure (MAP) after a decrease of at least 30 mm Hg from initial normal values, were compared to those taken during the 24 hours thereafter. In the 24-hour period prior to the hypotensive crisis, the 19 survivors demonstrated significantly greater cardiac index (CI), left cardiac work index (LCWI), oxygen delivery (DO2), and oxygen consumption (VO2) than the 14 patients who died. No other significant differences were found between the two patient groups. When sequential cardiorespiratory patterns were examined, significant increases in CI, LCWI, left ventricular stroke work index (LVSWI), DO2, and VO2 were present in survivors as early as eight hours before the hypotensive crisis. The results presented in this study suggest that patterns of survival may be determined in critically-ill septic patients before shock, as defined by the initial hypotensive episode, develops.

Aged↗
PubMed1984

Assessment of perfusion in the diabetic foot by regional transcutaneous oximetry.

Regional transcutaneous oximetry is a new, noninvasive diagnostic technique for the investigation of peripheral vascular disease (PVD) that uses differences in limb and trunk transcutaneous PO2 to assess the adequacy of local perfusion. The application of such measurements would be of great importance in diabetes, in which limb ischemia is commonly difficult to assess. A group of diabetic subjects with symptomatic PVD was studied with regional oximetry, Doppler-assisted blood pressure measurements, and arteriography. Doppler studies correlated poorly to symptom grade and angiographic data, while oximetry clearly demonstrated limb hypoxia under the functional conditions appropriate to the patients' clinical symptomatology. The superiority of oximetry to Doppler studies was highly significant (X2 = 12.64, P less than 0.001). Regional transcutaneous oximetry should therefore be the noninvasive diagnostic test of choice in the initial evaluation of the diabetic limb for PVD. Because of its dependence on the adequacy of local oxygenation, transcutaneous oximetry is a powerful tool for investigation of the pathophysiology of PVD and will, in the future, have wide-ranging applications to the diagnosis and therapy of PVD.

Aged↗
PubMed1984

Sequential hemodynamic and oxygen transport abnormalities in patients with acute pancreatitis.

Physiologic abnormalities were evaluated by sequential hemodynamic and oxygen transport measurements in 33 patients with acute pancreatitis. The hypotensive crisis, which was defined as the lowest mean arterial pressure (MAP), was used as the common temporal reference point to align the data in a coherent fashion. The data of the 48-hour periods before and after the hypotensive crisis then were evaluated. The patients were divided into normotensive and hypotensive groups and the latter were divided into survivors and nonsurvivors to evaluate the severity of the disorder and to identify the patterns representative of survival and death. The physiologic abnormalities of the hypotensive patients include decreased systemic vascular resistance index (SVRI) and compromised cardiac function. The latter was demonstrated during the hypotensive episode by significantly reduced left ventricular stroke work index (LSWI), despite increases in heart rate (HR), central venous pressure (CVP), pulmonary capillary wedge pressure (WP), and cardiac index (CI). The normotensive group had increased oxygen consumption (Vo2), oxygen delivery (Do2), pulmonary shunt (Qsp/Qt), LSWI, normal SVRI, and high CI. The hypotensive nonsurvivors had lower MAP, LSWI, SVRI, Do, and hematocrit as well as higher pulmonary vascular resistance index (PVRI) and Qsp/Qt than did the survivors. These findings do not support myocardial depression as the primary cardiovascular abnormality in acute pancreatitis, but rather suggest the decreased vascular tone from flow maldistribution in the peripheral microcirculation limits tissue oxygenation in the face of increased metabolic requirements of the hypercatabolic state.

Acute Disease↗
PubMed1984

Hemodynamic and oxygen transport effects of prostaglandin E1 in patients with adult respiratory distress syndrome.

The hemodynamic and oxygen transport effects of prostaglandin E1 (PGE1, Prostin -VR), in increasing doses from 1 to 30 ng/kg X min were evaluated in 5 severely ill surgical patients with adult respiratory distress syndrome (ARDS). This agent produced marked reductions in pulmonary arterial and venous pressures, and increases in cardiac output and oxygen transport. Improvement in PaO2 occurred several hours after these effects. The data indicate that this agent may be a useful adjunctive therapy for ARDS.

Cardiac Output↗
PubMed1984

Pathophysiologic classification of peripheral vascular disease by positional changes in regional transcutaneous oxygen tension.

The clinical manifestations and prognosis of peripheral vascular disease (PVD) depend upon the severity of limb hypoxia. Transcutaneous oxygen tension (Ptco2) is related to tissue oxygenation, but limb Ptco2 varies with changes in systemic as well as peripheral oxygen delivery (Do2). Previously we have found that simultaneous assessment of limb and chest Ptco2 yields a ratio, or regional perfusion index (RPI), that is independent of systemic Do2 and accurately reflects the adequacy of limb perfusion. Analysis of segmental limb Ptco2, RPI, and position-induced RPI changes was performed in 24 control limbs and 14 limbs with intermittent claudication (IC), 8 limbs with rest pain (RP), and 7 limbs with gangrene (G). Control limbs had high RPI values that varied little with position. The IC group had modestly decreased RPIs in the supine position, but extremity RPIs decreased markedly during leg elevation. Patients with RP had ischemia while supine, but the RPI improved to nearly normal upon standing. Feet with G were hypoxic even in the standing position. Segmental RPI decreases correlated with the presence of significant arterial lesions. This correlation was unaffected by diabetes. Analysis of regional transcutaneous oximetry allows classification of PVD by quantitative criteria based upon the adequacy of limb perfusion under functional conditions. RPI is characteristically high in normal persons and low in persons with G. Limbs with marginally compensated perfusion may have nearly normal RPI values under some conditions, but typical ischemic changes are elicited by positional change and exercise. The ease of such provocation of RPI decreases constitutes an index of the severity of disease. Such quantitative assessments of limb hypoxia can form the basis for a physiologic approach to arterial reconstruction.

Aged↗
PubMed1983

The transconjunctival oxygen monitor.

The transconjunctival oxygen monitor, mounted on a polymethylmethacrylate conformer, continuously measures the tissue oxygen tension of the palpebral conjunctiva. It is preferable to transcutaneous monitors because it requires no heat and correlates arterial oxygen in cerebral blood flow by monitoring a tissue bed vascularized by the internal carotid artery. We used it on 19 adult patients. The monitor was valuable in correlating arterial oxygen in hemodynamically compromised and uncompromised patients. However, the measurements decreased abruptly when the conjunctival temperature fell below 33 C in the compromised patients. The only ocular complications were conjunctival chemosis and mild punctate keratopathy in some patients; these resolved within 48 hours. This device may be useful in monitoring tissue oxygen tensions in critically ill patients and neonates at risk for retinopathy.

Conjunctiva↗