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Biomedical subjects

H B Kram

Publications and source records attributed to H B Kram.

At least 73 records · Page 4Linked to original sources
PubMed1987

Clinical and radiographic indications for aortography in blunt chest trauma.

To determine which clinical and radiographic findings are valuable in selecting patients with blunt chest trauma for aortography, we analyzed the medical records and admission chest radiographs of 76 consecutive victims of blunt chest trauma with suspected thoracic aortic rupture during the past 7 years. All patients were evaluated by history, physical examination, chest radiography, and aortography; a total of 70 clinical and radiographic findings were independently assessed in each patient. The following occurred with significantly greater frequency in patients with thoracic aortic rupture than in those without: history of significant hypotension (mean arterial pressure less than 80 mm Hg) (p less than 0.04); the presence of upper extremity hypertension, bilateral lower extremity pulse pulse deficits, or an initial chest tube output greater than 750 ml of blood (p less than 0.05); and greater incidence of myocardial contusions, intra-abdominal injuries, and pelvic fractures compared with patients without thoracic aortic rupture (p less than 0.05). Mediastinal widening (equal to or greater than 8 cm) shown on anteroposterior chest radiography occurred in all patients with thoracic aortic rupture; however, its specificity was only 10.6%. Radiographic signs that were helpful in indicating the presence of thoracic aortic rupture included paratracheal stripe greater than 5 mm, rightward deviation of the nasogastric tube or central venous pressure line, blurring of the aortic knob, and an abnormal or absent paraspinous stripe. Upper rib fractures and mediastinal to thoracic cage width ratios at any level did not increase diagnostic accuracy for thoracic aortic rupture in the present series. Six patients in the series died, two of whom had thoracic aortic rupture.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1987

Determination of optimal positive end-expiratory pressure by means of conjunctival oximetry.

A method for determining the optimal level of positive end-expiratory pressure (PEEP) by means of noninvasive conjunctival oxygen (PcjO2) monitoring and arterial blood gas analysis was developed from the pattern of changes in PcjO2 tension, invasive hemodynamic parameters, and oxygen transport variables during PEEP titration in a series of patients with adult respiratory distress syndrome. All patients had radial and pulmonary artery (PA) catheters inserted and blood volume was measured with 125I serum albumin before each study. During progressive increases in the level of PEEP, PcjO2 tensions reflected changes in both PaO2 and cardiac index (CI), depending on whether PEEP produced a significant decrease in CI. In patients with a stable CI, PcjO2 tensions tracked PaO2 values (rw = 0.92); in patients with a greater than a 15% decrease in CI, the conjunctival index, CjI (defined as the PcjO2/PaO2 ratio), tracked CI (rw = 0.87), excluding one patient with high cardiac output-septic shock and severe hypoxemia. PcjO2 correlated with PaO2 in the latter patient (r = 0.99) probably because conjunctival oxygen transport was limited by arterial oxygen content (PaO2 = 34 torr) rather than blood flow (CI greater than 6 L/min X m2). In patients with a greater than a 10% decrease in CI as a result of PEEP, the greater the decrease in CI, the better CjI values correlated with CI. We conclude that PcjO2 monitoring combined with repeated arterial blood gas analysis may be used to titrate PEEP therapy in patients with adult respiratory distress syndrome. In patients whose CjI significantly decreases because of PEEP, PA catheterization and measurement of cardiac output are indicated because of the likelihood of a significant (greater than 15%) decrease in CI. In the absence of a significant decrease in the CjI, optimum PEEP occurs at the level producing maximum PcjO2. It is hoped that by following the described algorithm, many patients will be spared the cost and morbidity of unnecessary PA catheterization.

Adult↗
PubMed1986

Noninvasive conjunctival oxygen monitoring during carotid endarterectomy.

Conjunctival oxygen tension (PcjO2) was measured continuously during carotid endarterectomy in 15 patients to evaluate its sensitivity in patients receiving shunts. These studies suggest that PcjO2 tracks brain perfusion during periods of carotid artery occlusion. Reduced PcjO2 was clearly demonstrated with systemic hypotension, carotid artery clamping, and carotid shunt obstruction and clamping. Monitoring of PcjO2 is noninvasive, easy to perform, offers no danger to the patient, and allows real-time assessment of the local tissue perfusion. It provides valuable information on the effectiveness of carotid oxygen transport and, in conjunction with arterial blood gas values, expresses carotid artery perfusion relative to systemic oxygen transport. Further investigations using the PcjO2 sensor may define criteria for intraoperative carotid arterial shunting in patients with tenuous cerebral perfusion, and for prompt intervention in patients with deteriorating perfusion prior to the onset of life-threatening cerebral ischemia.

Aged↗
PubMed1986

Assessment of intestinal and renal perfusion using surface oximetry.

Using a miniaturized polarographic oxygen sensor, we studied the sequential effects of graded hypoxia and standardized hemorrhagic shock on organ surface oxygen tension (PsO2) measurements obtained from the canine small intestine and kidney. During hypoxia, intestinal and renal PsO2 values decreased along with PaO2. The weighted mean correlation coefficients for intestinal and renal PsO2 vs. PaO2 were 0.94 and 0.98, respectively. During severe hypoxia, intestinal and renal PsO2 values fell by 55 +/- 8% and 55 +/- 7% (SEM), respectively, while oxygen delivery fell by 58 +/- 10% (SEM). During active hemorrhage, intestinal and renal PsO2 values decreased along with cardiac output, while PaO2 remained relatively constant. Intestinal and renal PsO2 values correlated with cardiac output during hemorrhage and reinfusion of the shed blood. Initially, intestinal PsO2 values fell more quickly than did renal PsO2; the latter decreased by approximately half as much as intestinal PsO2 after 15 and 30 ml/kg of blood loss. After a 45-ml/kg blood loss, however, the decreases in intestinal and renal PsO2 values were not significantly different from each other. During the terminal stage, cardiac output declined progressively, as did intestinal and renal PsO2 values, despite a relatively high PaO2. Overall, intestinal and renal PsO2 values tracked PaO2 during hypoxia, cardiac output during hemorrhage and reinfusion, and oxygen delivery during both conditions. Clinical and experimental experience indicates that organ PsO2 monitoring is potentially valuable for the intraoperative assessment of tissue perfusion and viability.

Animals↗
PubMed1986

Comparison of measurements of cardiac output by bioimpedance and thermodilution in severely ill surgical patients.

In order to evaluate a new thoracic electrical bioimpedance (TEB) system for measurement of stroke volume based on the Sramek-Bernstein equation, 391 paired values of cardiac output were measured simultaneously with the standard thermodilution method. These values were obtained from 16 patients selected for having the most severe illness during a 6-month period; the intent was to evaluate the bioimpedance method in the worst possible situations. The correlation coefficient (r) was 0.83, slope was 0.87, intercept was 1.53, and the mean difference between the two methods was 16.2 +/- 11.8 (SD)% in the total series. In 285 paired samples where satisfactory conditions were met, r was 0.90, slope was 0.98, intercept was 0.34, and the mean difference was 11.8 +/- 8.9%. The data indicate satisfactory correlations between these two methods. When the TEB waveform is satisfactory, the agreement between TEB and thermodilution is as good as the agreement between serial thermodilution methods. Difficulties may arise with dysrhythmias, tachycardia (heart rate greater than 150 beat/min), metal in the chest or chest wall, sepsis, hypertension, and extremely oily skin. Mechanical ventilation did not appear to be a problem.

Cardiac Output↗
PubMed1986

Hemodynamic and oxygen transport effects of dobutamine in critically ill general surgical patients.

The effects of dobutamine on hemodynamic and oxygen transport were evaluated in 43 studies on 34 critically ill general (noncardiac) surgical patients. Dobutamine, beginning at a low dose (2.5 micrograms/kg X min) significantly increased cardiac index (CI), oxygen delivery (DO2), and oxygen consumption (VO2), while decreasing mean arterial pressure, pulmonary artery and wedge pressures, and systemic and pulmonary vascular resistances; blood gases, pH, and pulmonary shunt were not significantly changed. These effects were seen in postoperative and septic patients, as well as in patients with normal, low, and high control CI. These responses were poor in terminally ill and hypovolemic patients; however, when the latter were given additional fluids, their responses were markedly improved. The hemodynamic effects of dobutamine are well known, but the DO2 and VO2 effects, which suggest improved tissue perfusion, have not been appreciated.

Adolescent↗
PubMed1986

Conjunctival and mixed-venous oximeters as early warning devices of cardiopulmonary compromise.

To evaluate potential clinical applications of conjunctival (PcjO2) and mixed venous (SvO2) oximeters in the care of surgical patients, we compared continuous measurements of PcjO2 and SvO2 to conventional invasive hemodynamic and oxygen transport variables during normoxia, hyperoxia, hypoxia, hemorrhagic shock, and resuscitation in dogs. During the normoxic control periods, PcjO2 averaged 76% of the arterial oxygen tension (PaO2). During hyperoxia and hypoxia, PcjO2 correlated well with PaO2 values (r = 0.88) but not with mixed venous oxygen tension (PvO2), whereas the SvO2 correlated well with PvO2 (r = 0.88) but not with PaO2 values. Controlled hemorrhage produced significant, progressive decreases in PcjO2, SvO2, cardiac output, and oxygen delivery (P less than 0.01), whereas PaO2 values remained constant throughout this period (FIO2 = 40%). There were no significant differences between the decreases in PcjO2 and SvO2 at 15, 30, and 45 ml/kg blood loss. Reinfusion of the shed blood resulted in a rapid, significant increase in PcjO2, SvO2, cardiac output, and oxygen delivery (P less than 0.01); the PaO2 remained constant. During hemorrhage and resuscitation, both PcjO2 and SvO2 tracked cardiac output; the weighted mean correlation coefficient, rw, was 0.90 for both PcjO2 versus cardiac output and SvO2 versus cardiac output. The correlation coefficient for PcjO2 versus SvO2 during hemorrhage and resuscitation was 0.72. One dog died unexpectedly during hemorrhage. In the 29 min period immediately prior to death, PcjO2 remained at 9 torr and SvO2 at 10%; the simultaneously measured PaO2 was 133 torr. Both oximeters had in vivo stabilization and 90% response times of less than 2 min. We conclude that both oximetry systems are potentially useful in high-risk surgical patients to provide better cardiorespiratory surveillance and to signal the need for more intensive assessment of hemodynamic stability. This approach may lead to reduced costs from unnecessary invasive procedures as well as reduced morbidity secondary to earlier warning of cardiorespiratory compromise.

Animals↗
PubMed1985

Common bile duct anastomosis using fibrin glue.

Transection of the common bile duct (CBD) secondary to iatrogenic or civilian trauma is a devastating injury associated with a high incidence of complications, especially biliary fistula and stricture formation. We evaluated the efficacy of Fibrin Sealant--a biologic adhesive containing highly concentrated human fibrinogen--in primary end-to-end anastomosis of the transected CBD in ten adult mongrel dogs. Postoperative T-tube stents in the CBD anastomosis and abdominal drainage were not used. Only two absorbable sutures were used for each CBD anastomosis. The dogs were reexplored postoperatively at intervals varying from one week to nine months; cholangiography was performed at postoperative intervals varying from one to six months. Examination of CBD specimens harvested one month or more after surgery revealed complete healing and no signs of previous injury. Histologic examination disclosed well-healed ductal tissue, without a significant inflammatory response. One dog had an anastomotic leak, and two had moderate narrowing of the CBD anastomosis. Our experience in experimental CBD anastomosis indicates that Fibrin Sealant helps seal biliary anastomoses against leakage; controls bleeding from cut edges of bile duct segments; has good systemic and local compatibility; may promote bile duct wound healing; and significantly reduces the number of sutures needed for primary repair, thereby decreasing the potential for anastomotic ischemia, mucosal damage, and biliary stricture formation.

Animals↗
PubMed1985

Noninvasive tissue oxygen monitoring in surgical and critical care medicine.

Noninvasive tissue oxygen monitoring techniques are becoming increasingly important as a means for assessing perfusion and oxygenation in clinical and experimental medicine. Applications of several oxygen monitoring modalities in surgical and critical care medicine are described.

Arterial Occlusive Diseases↗
PubMed1985

Continuous polarographic monitoring of intra-arterial oxygen in the perioperative period.

Intra-arterial PO2 (PiO2) was polarographically monitored in ten critically ill patients during induction of anesthesia, the intraoperative period, extubation, and the immediate postoperative period; 147 PiO2 values were then paired with simultaneous measurements of PaO2. Mean PiO2 closely followed mean PaO2 over a wide range of values (r = .97), and the continuous, online real-time PiO2 readings provided a useful early warning system for hypoxemia during crisis periods. Technical problems included catheter clotting from improper flushing, changes in PiO2 due to changes in body temperature, the need for in vitro and in vivo calibration, and sensor drift. However, these problems were resolved by appropriate catheter management and sensor calibration.

Blood Gas Analysis↗
PubMed1985

Transcutaneous oxygen recovery and toe pulse reappearance time in the assessment of peripheral vascular disease.

The accuracy of measurements of transcutaneous oxygen tension (Ptco2) in the diagnosis of peripheral vascular disease (PVD) may be significantly increased by stressing limb circulation with the use of temporary ischemia. The purpose of this study was to compare the transcutaneous oxygen recovery half-time (TORT) and the toe pulse reappearance time (PRT/2) in a series of patients with symptomatic PVD before and after vascular reconstruction. The TORT was defined as the time required to recover half of the decrease in the limb/chest Ptco2 ratio caused by temporary limb ischemia, and is conceptually comparable to the toe PRT/2, the time required to recover half of the control toe pulse amplitude. Measurement of TORT was found to be more feasible (100% vs 58%) and to have a greater diagnostic yield (100% vs 92%) than that of the toe PRT/2. When measured on the dorsum of the foot, TORT values were found to correlate well with the severity of symptoms of PVD; toe PRT/2 values did not correlate with severity of symptoms. Patients who underwent successful vascular reconstruction had significant improvement in their calf and foot TORT values after surgery (p less than .005 and .0005, respectively); postoperative values were similar to those obtained in normal subjects. Toe PRT/2 values usually improved postoperatively, but in many patients postoperative values overlapped with values that were considered abnormal. There was no overlap of TORT values in normal subjects with those in patients with symptomatic PVD. The measurement of TORT may be clinically useful for screening patients with suspected PVD and for assessing quantitatively the results of conservative and surgical therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Tracheal repair with fibrin glue.

This animal study evaluated Fibrin Sealant, a multicomponent biologic adhesive, in tracheal operations. We conclude that the use of Fibrin Sealant in tracheal reconstruction results in a stable, leakless trachea, has good systemic and local compatibility, promotes tracheal wound healing, and reduces significantly the number of sutures required for end-to-end anastomosis.

Animals↗
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↗