Biomedical subjects
Publications and source records attributed to W C Shoemaker.
We describe a case of incarcerated rectal prolapse caused by blunt abdominal trauma. Emergency treatment consisted of manual reduction with the patient under general anesthesia, proctosigmoidoscopy, and peritoneal lavage. Subsequent definitive surgical therapy was then performed after bowel preparation and consisted of anterior resection of the sigmoid colon with posterior (sacral) rectopexy.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In order to evaluate potential applications of non-invasive fiberoptic conjunctival carbon dioxide (Pcj,CO2) and polarographic oxygen (Pcj,O2) sensors, we studied the effects of graded hyper- and hypoventilation on Pcj,CO2 and Pcj,O2 values in dogs. Pcj,CO2 values correlated well with Pa,CO2 (r = 0.95, n = 114); the mean Pcj,CO2--Pa,CO2 gradient was 4 +/- 3 (S.D.) Torr. Both hyper- and hypoventilation resulted in decreased Pcj,O2 values, whereas decreased Pa,O2 was observed only during hypoventilation; thus, the Pcj,O2/Pa,O2 index decreased during hyperventilation but was maintained during hypoventilation. Because both cerebral and conjunctival capillary beds vasoconstrict during hyperventilation, this methodology may assist in the non-invasive monitoring of cerebral oxygenation during cerebral resuscitation and surgery. Non-invasive Pcj,CO2 monitoring, which reflects Pa,CO2 during changes in ventilation, may be used to simplify ventilator management and weaning, as well as guide appropriate timing of arterial blood gas analysis in hemodynamically stable patients.
The present study examined prospectively the prognostic value of preoperative clinical findings, angiography, and conventional vascular hemodynamic and transcutaneous oximetry measurements in a consecutive series of patients undergoing lower extremity vascular reconstruction. A total of 25 variables were independently evaluated in each limb. Follow-up at least 6 months after operation was carried out in all patients. The postocclusive transcutaneous oxygen recovery time was found to be the most accurate predictor of short-term femoropopliteal bypass graft success. Preoperative foot transcutaneous oxygen recovery time values were significantly worse in patients whose femoropopliteal bypass grafts failed than in those in whom the outcome was successful (p less than 0.03). Transcutaneous oxygen recovery time values were also valuable in patients who underwent aortofemoral bypass; patients with isolated aortoiliac disease had significantly better foot transcutaneous oxygen recovery time values than those with combined aortoiliac and femoropopliteal disease (p less than 0.05). Foot transcutaneous oxygen recovery time values were also found to correlate well with the severity of symptoms (p less than 0.01), as did ankle-brachial Doppler pressure indices. Although the other variables analyzed provided useful diagnostic information, none were as accurate as the postocclusive transcutaneous oxygen recovery time in predicting the outcome of peripheral vascular reconstruction. As a means of more accurately classifying patients with peripheral vascular disease, we recommend the complimentary use of clinical findings, angiography, and hemodynamic and transcutaneous oximetry measurements. Because transcutaneous oxygen tension reflects the balance between local oxygen supply and demand, it may help to better define risk factors preoperatively in physiologic terms.
To evaluate potential clinical applications of nonautologous fibrin glue (FG) as a hemostatic agent in vascular surgery, we compared its efficacy to oxidized regenerated cellulose (OC) in hemostatically sealing polytetrafluoroethylene (PTFE) vascular graft anastomoses. PTFE grafts (4 mm wide and 4 to 6 cm in length) were placed to each femoral artery in a heparinized canine model, in end-to-end fashion in half of the dogs and in end-to-side fashion in the remaining dogs. Each set of graft-arterial anastomoses was then sealed with either FG or OC, determined randomly, followed by simultaneous measurement of blood loss through the graft anastomoses and needle holes. There was significantly less bleeding from anastomoses sealed with FG compared with those sealed with OC, regardless of whether the anastomoses sealed with FG compared with those sealed with OC, regardless of whether the anastomosis was constructed in end-to-end (p less than 0.03) or end-to-side (p less than 0.004) fashion; overall, the operative blood loss for grafts sealed with FG was 14 +/- 6 (mean +/- standard error of the mean) vs 99 +/- 27 ml/min for those sealed with OC (p less than 0.001). In the early postoperative period, significant groin hematomas occurred more frequently in grafts sealed with OC compared with those sealed with FG. Microscopic examination of graft-arterial specimens harvested at postoperative intervals ranging from 1 day to 3 months revealed no significant inflammatory reaction with either hemostatic agent; after 2 to 3 weeks, paired specimens appeared histologically similar despite previous treatment with either FG or OC.(ABSTRACT TRUNCATED AT 250 WORDS)
A retrospective analysis of all patients with traumatic thoracic aortic rupture (TAR) admitted to the hospital over a consecutive 10-year period was performed in order to define the incidence, morbidity, and mortality of associated cardiac contusion (CC) in patients with TAR. Of the 13 patients with TAR, eight (62%) had associated CC. All patients with CC had two or more of the following positive findings: abnormal ECG, elevated myocardial-band creatinine kinase levels, abnormal radionuclide angiography/left ventricular segmental wall motion studies, or cardiac damage seen at surgery and postmortem examination. Four patients with TAR suffered cardiac arrest; all of the latter patients had associated CC. After successful repair of the TAR, five of six patients with combined TAR and CC developed adult respiratory distress syndrome (ARDS), whereas only one of five patients with isolated TAR had ARDS. All patients with isolated TAR survived, whereas three of eight patients suffering combined TAR and CC died perioperatively, secondary to cardiac arrest. In patients with TAR, the presence of associated CC occurs with increased frequency, is associated with increased morbidity (cardiac arrest, ARDS), and results in increased operative mortality secondary to cardiac instability. A branch-chain decision tree (clinical algorithm) was developed as a means of improving management of patients with combined TAR and CC, including indications for preoperative pulmonary artery catheterization.
To evaluate potential clinical applications of a newly developed, noninvasive fiberoptic conjunctival carbon dioxide (PcjCO2) sensor designed to measure continuously tissue PCO2 in a vascular bed supplied by the internal carotid artery, we studied the effects of graded respiratory and metabolic alkalosis and acidosis on PcjCO2 in a hemodynamically stable canine model. Respiratory changes were induced by varying the frequency of ventilation and metabolic changes were induced by incremental infusions of sodium bicarbonate and hydrochloric acid. Continuous measurement of end-tidal carbon dioxide tension (PETCO2) was also performed. During respiratory alkalosis and acidosis, PcjCO2 values correlated well with PaCO2 (r = 0.96, n = 106); linear regression analysis of PcjCO2 vs. PaCO2 produced a slope of 1.01 and a y-intercept of 3.94 over a PaCO2 range of 12 to 76 torr. The mean PcjCO2-PaCO2 gradient was 4 +/- 3 (SD) torr. PETCO2 values also correlated well with PaCO2 (r = 0.91), as well as with PcjCO2 values (r = 0.91). Both PcjCO2 and PETCO2 showed a much weaker correlation with PaCO2 during metabolic alkalosis and acidosis, partly because the variation in PaCO2 was less. Moreover, the PcjCO2-PaCO2 gradient increased during the metabolic portion of the study up to a mean of 10 +/- 8 (SD) torr during metabolic acidosis, implying a build-up and/or lack of washout of CO2 from the conjunctival tissues, despite the normal physiologic range of PaCO2 values. We conclude that in a hemodynamically stable canine model, PcjCO2 and PETCO2 values correlate well with PaCO2 during pure respiratory alkalosis and acidosis; the correlation weakens significantly, however, with metabolic alterations in tissue CO2 levels.
Explore the source record for details and available documents.
A multicomponent noninvasive monitoring system for high-risk critically ill patients was developed and tested in a series of 58 high-risk surgical patients. The system was comprised of a thoracic electric bioimpedance (TEB) method for cardiac output estimation, laser-Doppler velocimeter for small vessel flow, transcutaneous oxygen (PtcO2) sensor for tissue oxygenation, pulse oximeter for arterial hemoglobin saturation (SaO2) and finger pressor sensor for arterial pressure. In a series of critically ill patients, this noninvasive system was compared with the widely used invasive monitoring system with systemic and pulmonary artery catheters. Despite theoretical limitations of TEB as a measure of cardiac output, there was a satisfactory correlation (r = .83) of cardiac output measured by thermodilution (TD) and TEB throughout a wide range of severe illnesses. Moreover, changes in TEB cardiac output satisfactorily tracked changes in TD cardiac output (r = .91). There was poor correlation between TD cardiac output and BP or heart rate. The incidence of abruptly changing physiologic patterns was observed with simultaneously monitored invasive and noninvasive systems. Descriptions were made of the central circulation, peripheral perfusion, and pulmonary function; common interactive responses of these circulations were also evaluated. Monitored events defined as abrupt reductions in these variables often occurred from reduced cardiac output, PtcO2 or PtcO2/PaO2 index, and infrequently from unanticipated reductions in SaO2. Recovery from the nadir of the monitored event was associated usually with improvements in flow, PtcO2, or both. Hemodynamic and oxygen transport patterns of a few commonly encountered patterns are described.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The aim of this study was to evaluate the concept that tissue oxygen debt reflected by inadequate oxygen consumption (VO2) in the intraoperative and immediate postoperative periods is a common determinant of multisystem organ failure and death. We measured the cumulative tissue oxygen debt during and immediately after 100 consecutive high-risk surgical operations in 98 patients and correlated these data with the subsequent development of lethal and nonlethal organ failure complications. The tissue VO2 deficit was calculated as the measured VO2 minus the estimated VO2 requirements corrected for both temperature and anesthesia; the net cumulative VO2 deficit was calculated as the integrated area under the VO2 deficit-time curve. The maximum cumulative VO2 deficit averaged 33.5 +/- 36.9 (SD) L/m2 in nonsurvivors, 26.8 +/- 32.1 L/m2 in survivors with organ failure, and 8.0 +/- 10.9 L/m2 in survivors without organ failure. The time postoperatively to reach the maximal cumulative VO2 deficit and the duration of the VO2 deficit was greatest in nonsurvivors, less in survivors with organ failure, and least in survivors without organ failure. Although many associated clinical conditions as well as innumerable physiologic mechanisms and biochemical mediators play important roles in tissue injury, tissue oxygen debt reflected by insufficient VO2 appears to be the primary event as well as a major determinant of organ failure and outcome.
The major aim was to develop a branch-chain decision tree for penetrating truncal injury and to subject this to a prospective trial of its feasibility to track management decisions. In contrast to the conventional trauma study which focuses on highly selected, well-defined surgical problems, this algorithmic approach was designed to look at the whole gamut of problems of unselected patients with penetrating injury as they enter the ED. The branch-chain algorithm primarily focuses on priorities, order of procedures, and the immediate therapeutic options. The algorithm was used to track clinical management of 280 consecutive patients with penetrating truncal injuries; 31 were dead on arrival, 12 were alive on admission but died during their hospitalization. Of 209 patients whose management was in satisfactory compliance, four (2%) died; eight (20%) of 40 patients who had major deviations from the algorithm died (p less than .01).
The aim of the present study was to examine the essential problems in a retrospective study of 381 organ injuries in 260 patients, to identify problems, to define criteria, to describe decision rules, and to organize these rules into branch-chain decision trees or clinical algorithms. The basic hypothesis of this study is that criteria organized into a prioritized decision tree can provide objective standards to evaluate the quality of trauma care and to compare alternative approaches. The algorithm was designed to provide prompt therapy for the most life-threatening problems: respiratory and cardiac arrest, shock, head injury, tamponade, lacerations of the great vessels, cardiac contusion, ruptured parenchymal organs, lacerated viscera, and injury to other intraperitoneal organs. Resuscitation from shock, correction of circulatory problems, and monitoring of physiologic variables were prioritized to evaluate the presence of circulatory deficits and the adequacy of specific therapy to correct them. Concomitantly, diagnosis of the underlying problems was approached using peritoneal lavage, abdominal and chest x-rays, iv urograms, cystograms, endoscopy, upper and lower GI barium or hypaque studies, ultrasound, scintograms, and CT scans. In emergency conditions these are limited to a large extent by time factors. The diagnostic accuracy, priorities, and limitations of each of these were evaluated in emergency conditions. The algorithm was used to track management decisions in a prospective series; the mortality of 51 patients with satisfactory compliance was 4% and 44% in nine patients with major deviations from the algorithm.
We evaluated the efficacy and safety of fibrin glue (FG) made with highly concentrated human fibrinogen and clotting factors in achieving hemostasis of superficial and deep hepatic injuries. Experimentally produced hepatic injuries were produced in 12 adult mongrel dogs and hemostatically sealed with FG. Half of the dogs each received two penetrating hepatic injuries consisting of a large laceration and a deep stab wound through the liver; the remaining dogs underwent resection of a large segment of the left lobe of the liver. Hemostasis was achieved by applying FG into and over the bleeding wounds; hepatic arterial occlusion was not used. Complete hemostasis was achieved in all animals before skin closure. One dog from each group was re-explored and the liver specimens harvested for gross and microscopic examination at postoperative intervals of 12 hours, 24 hours, and 2, 3, 6, and 8 weeks. There were no cases of intra-abdominal infection, abscess formation, or bile fistulae. Histologic examination demonstrated a thickened capsule containing fibrous connective tissue and neovascular proliferation; there were no signs of local or systemic toxicity. One dog died on postoperative day 1 from rebleeding from the hepatic injury; all other dogs survived without complications. We conclude that FG provides effective hemostasis of superficial and deep hepatic injuries, and has good systemic and local compatibility. Its use in surgery for hepatic trauma may lead to less intraoperative blood loss and transfusion requirements, as well as a reduced need for major hepatic resection to control hemorrhage.
Explore the source record for details and available documents.
Survivors of high-risk surgical operations were previously observed to have significantly higher mean CI, DO2, and VO2 than nonsurvivors. The hypothesis was proposed that increased CI and DO2 are circulatory compensations for increased postoperative metabolism. We tested this hypothesis in two series. In series 1, prospectively allocated by services, mortality and morbidity of the control group were significantly greater than those of the protocol group. In series 2, patients who fulfilled previously defined high-risk criteria were preoperatively randomized to one of three monitoring/treatment groups: CVP-control group, PA-control group and PA-protocol group. Postoperative mortalities in the CVP-control and PA-control groups were not statistically significantly different, but PA-protocol group mortality was significantly reduced compared with its control group. The PA-protocol group had reduced complications, duration of hospitalization, duration in ICU, and mechanical ventilation, and reduced costs when the PA catheter was placed preoperatively and used to augment circulatory responses.