Biomedical subjects

A S Geha

Publications and source records attributed to A S Geha.

At least 37 records · Page 2Linked to original sources

PubMed1996

Cost analysis of early extubation after coronary bypass surgery.

BACKGROUND: Although early extubation after coronary bypass surgery has been shown to reduce length of stay, a systematic cost analysis of its economic benefit has not been reported, and previous studies have used hospital charges that are typically confused with actual costs. METHODS: A consecutive series of 690 patients undergoing coronary bypass surgery during a 24-month period were studied to determine the effect of early extubation, defined as removal of the endotracheal tube within 8 hours of arrival to the intensive care unit, on length of stay and hospital costs. Patients in group 2 (n = 362) who underwent coronary bypass surgery in 1995, subsequent to the initiation of an early extubation protocol, were compared with those in group 1 (n = 328) operated on in 1994, before implementation of early extubation. To reflect true hospital resource consumption, only costs (not charges) directly related to patient health core (variable direct cost) were analyzed. RESULTS: Baseline characteristics such as age, gender, previous myocardial infarctions, ejection fraction, reoperations, diabetes, and left main stenosis were similar in both groups. Operative mortality for the entire group was 3.3% and did not differ between the two groups; the incidence of serious morbidity was 10.9% for the entire group. Early extubation was accomplished in 38% of patients in group 2 versus 3% in group 1 (p < 0.001), and postoperative length of stay declined from 9.4 days to 7.7 days (p < 0.01). This was accompanied by a significant (p = 0.001) reduction in variable direct cost per case. CONCLUSIONS: Early extubation after coronary bypass surgery is an effective strategy of reducing length of stay and does not appear to impact on either morbidity or mortality. An additional benefit is significant cost savings realized through accelerated recovery and control of resource use.

Adult↗

PubMed1996

New approach for replacement of degenerated mitral bioprostheses.

OBJECTIVE: The most common indication for reoperation in patients with a mitral bioprosthetic valve is primary tissue failure. Explanation of the bioprosthesis is time-consuming and may be complicated by cardiac rupture at the atrioventricular junction or the posterior left ventricular wall where a strut is imbedded, injury to the circumflex artery and late perivalvular leak. A new approach to avoid these complications by excising only the bioprosthetic tissue and attaching a reversed aortic St. Jude valve to the intact stent has been developed and evaluated. METHODS: We have replaced degenerated mitral bioprostheses with a St. Jude valve in 73 patients during the last 12 years. In 57, including all who had their operation before 1991, explantation was used. The stent was preserved in 16 patients; in the first four we implanted a mitral St. Jude valve (SJM) within the stent, but this only allows a SJM 6-8 mm smaller than the bioprosthesis. We evolved our approach in the last 12 patients to suture a reversed aortic St. Jude valve with extended cuff to the atrial side of the bioprosthetic cuff; this allows the use of a St. Jude valve 2 mm smaller than the bioprosthesis with exact matching of the orifice sizes. The demographic and clinical profiles of the two groups were similar. RESULTS: Operative mortality was 8/57 (14%) in the explantation group and none in the stent-preservation group. Three late perivalvular leaks occurred in the explanation group, and none in the stent-preservation group. Thirteen late deaths occurred in the explanation group, with a 5-year survival rate of 68%, and one late death (cancer) in the stent-preservation group, but the follow-up is significantly shorter. CONCLUSIONS: Leaving the mitral bioprosthetic stent and cuff intact eliminates the need for extensive dissection, thus shortening and simplifying the procedure and diminishing its attendant mortality and morbidity. It offers a safe and logical approach to replacement of a degenerated mitral bioprosthesis with a St. Jude valve of comparable size which projects into the left atrium, rather than a smaller one jammed into the orifice of the bioprosthetic stent.

Adult↗

PubMed1996

Salvage of infected ICDs: management without removal.

During the 7-year period from August 1986 to December 1993, 242 patients with malignant ventricular arrhythmias underwent 242 ICD implantations and 50 subcutaneous generator changes. Wound infections developed in 5 patients (1.7%): in 3 cases, after primary implantation (3/242 [1.2%]); and in 2 following a generator change (2/50 [4.0%]). This difference was not statistically significant. Infection developed at the generator pocket and became clinically manifest between 6 weeks and 40 months, postoperatively. Our treatment approach with the first patient consisted of simple debridement of the pocket and reimplantation of the existing generator. This led to recurrence, and the generator was safely explanted. In the remaining four patients, our approach has been that of local treatment, with wide debridement of the pocket, and placement of a closed irrigation system with continuous irrigation with a bacitracin, polymyxin, neomycin solution, and culture-specific antibiotic therapy. We have successfully controlled the infection and salvaged the generator with this approach in all four patients, who are all alive and well at a mean follow-up of 25.0 +/- 17.3 months with no recurrence. The good results obtained in these patients suggest that the concept of total explanation of the infected ICD should be reassessed.

Aged↗

PubMed1995

Atrial defibrillation using temporary epicardial defibrillation stainless steel wire electrodes: studies in the canine sterile pericarditis model.

OBJECTIVES: This study sought to determine whether temporary epicardial wire electrodes can be used safely and effectively to defibrillate the atria with low energy shocks in the absence of anesthesia. BACKGROUND: Atrial fibrillation after open heart surgery is a significant clinical problem. METHODS: Twelve dogs with sterile pericarditis were studied. In the first group (6 dogs, bilateral thoracotomy group), a wire electrode, insulated except for the distal 6 cm, was placed on the epicardial free wall of each atrium. Each end of the bare wire was then sutured to the parietal pericardium. In the second group (6 dogs, median sternotomy group), the wire electrodes were kept in place by a double loop of Prolene placed around the distal tip of the bare wire and sewn to the overlying parietal pericardium. In the bilateral thoracotomy group, atrial defibrillation thresholds (defined as < 90% and > 10% successful defibrillation of 20 shocks at a given delivered energy) were obtained in anesthetized dogs using the wire electrodes with the chest closed and open and using two transvenously placed catheters with coil electrodes in the distal 6 cm (one in the coronary sinus and the other in the right atrial appendage) with the chest open. In the median sternotomy group, thresholds were obtained in minimally sedated animals without reopening the chest. A 25% increase above threshold shock was also used to determine a new percent success. After 4 days, the wire electrodes were removed by pulling on the external ends. At the time of removal, blood pressure and heart rate were monitored for 30 min, after which dogs were killed and their hearts sent for histopathologic study. For all dogs, chest radiographs were obtained postoperatively and on study days. RESULTS: Atrial defibrillation using the wire electrodes was successful in all dogs at a mean (+/- SE) voltage of 112 +/- 9 V, with an energy level of 0.46 +/- 0.07 J and an impedance of 59.3 +/- 5 ohms. The mean percent success at the atrial defibrillation threshold was 36 +/- 5%. The 25% increase in defibrillation voltage improved the mean percent success to 73% (mean energy 0.66 +/- 0.19 J). No clinical or hemodynamic complications were observed during shock delivery, and no ventricular arrhythmias were induced during the shocks. No complications followed wire electrode removal. Histopathologic analysis showed no structural damage. CONCLUSIONS: The atrial defibrillation threshold obtained using temporary epicardial wire electrodes for atrial defibrillation is < 1 J in dogs. Atrial defibrillation using temporary epicardial wire electrodes can be performed safely, quickly and reliably without the need for anesthesia or antiarrhythmic agents. The wire electrodes can be removed without adverse hemodynamic or structural consequences. These data provide a basis for testing atrial defibrillation using epicardial wire electrodes in patients after open heart surgery.

Algorithms↗

PubMed1995

Arteriovenous malformation of the esophagus disguised as a leiomyoma.

Hemangiomas, benign tumors of vascular origin, compromise less than 3% of all nonmalignant esophageal neoplasms. Because of their infrequent occurrence, such vascular tumors may be mistaken for more common benign tumors of the esophagus. We report the successful surgical management of an esophageal arteriovenous malformation presenting with clinical, radiographic, and endoscopic features resembling those of a leiomyoma.

Aged↗

PubMed1995

Combined internal cardioverter-defibrillator implantation and myocardial revascularization for ischemic ventricular arrhythmias: optimal cost-effective strategy.

During the 7-year period from August 1986 to July 1993, 203 patients with malignant ventricular arrhythmias underwent 203 implantable cardioverter-defibrillator (ICD system) implantations at the University Hospitals of Cleveland. Sixty-four patients had significant coronary artery stenoses amenable to myocardial revascularization and thus, at the time of the operation for ICD placement, also underwent coronary artery bypass graft. A retrospective analysis of the course of these 64 patients was carried out to determine the effect of two different treatment strategies on the outcome and cost of therapy. Thirty-six patients (group 1) underwent concomitant implantation of the ICD leads, patches and generator at the time of myocardial revascularization; 28 patients (group 2) underwent a two-stage strategy of initial placement of the ICD leads and patches at the time of myocardial revascularization followed by postoperative electrophysiologic testing to determine the persistent need for generator implantation. Of this latter group, 16 patients still had inducible sustained ventricular tachycardia during postoperative electrophysiologic testing and underwent generator implantation; 12 patients did not receive an ICD generator. The overall 30-day mortality rate was 4.7%. Two patients died in group 1 for a mortality rate of 5.5% and one died in group 2 for a mortality rate of 3.6%. The mean(s.d.) length of stay was 22.8(9.6) days at a mean(s.d.) cost of $93,000(33,000) for group 1 and 24.5(9.6) days at a mean cost of $82,900(30,000) for group 2 (P = n.s.). The mean(s.d.) postoperative length of stay was 13.7(7.8) days for group 1 and 15.4(6.5) days for group 2 (P = n.s.). Other complications occurred in 23% of surviving patients in group 1 and 29% of surviving patients in group 2 (P = n.s.). Mean follow-up was 33 months for group 1 and 23 months for group 2. At the end of 2 years, 78% of patients in group 1 and 86% in group 2 were alive (P = n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Evolution of the surgical approach for replacement of degenerated mitral bioprostheses.

BACKGROUND: Primary tissue failure is the most frequent indication for reoperation in patients with a mitral bioprosthetic valve (MBPV). Complete excision of the bioprosthesis is time-consuming and may be complicated by cardiac rupture at the atrioventricular junction or the posterior left ventricular wall where a strut is embedded, injury to the circumflex coronary artery, or late perivalvular leak. A new approach to avoid these complications by excision of only the bioprosthetic tissue and attachment of a St. Jude valve (SJV) to the intact stent has been developed and evaluated. METHODS: The results of replacement of failed MBPV with SJV in 71 consecutive patients between September 1992 and December 1994 were analyzed; 57 patients had the valve replaced after complete excision and 14 with stent preservation. The demographic and clinical profiles of the two groups were similar. RESULTS: Among patients undergoing complete excision of the MBPV, operative mortality was 14% (8 of 57), with 12 late deaths and a 5-year survival of 75% and three late perivalvular dehiscences requiring another operation. No operative deaths occurred in the intact stent group and one late death (cancer), and all the remaining patients are doing well without perivalvular leaks or other complications. CONCLUSIONS: Leaving the MBPV stent intact eliminates the need for extensive dissection, thus shortening and simplifying the procedure and diminishing its attendant mortality and morbidity. It offers a safe and logical approach to replacement of a degenerated MBPV with a SJV of comparable size.

Adult↗

PubMed1993

Retrograde cardioplegia cannulation during cardiopulmonary bypass.

A simplified method of transatrial cannulation of the coronary sinus during cardiopulmonary bypass, with the heart completely decompressed, is described. The technique is easy to adopt and inherently safe because the catheter is guided toward the great cardiac vein visually, rather than by manual palpation.

Cardiac Catheterization↗

PubMed1993

Blood lost and blood transfused in coronary artery bypass graft operation as implications for blood transfusion and blood conservation strategies.

We have analyzed the relationship between blood lost and blood transfusions given to 498 consecutive patients undergoing primary elective coronary artery bypass graft operations at 18 institutions. Seventy-nine percent of blood and 59 percent of patients were transfused only on the day of the operation. Patients who received none, 1 or 2 units of blood were not different when analyzed for blood transfusion risk factors except for the percentage of patients who were female. We identified 91 patients who received transfusion inappropriately, using a clinical indicator that analyzed blood losses for each patient. Forty-nine percent of all patients transfused could have avoided exposure to homologous blood if the equivalent of 4 units of the blood in erythrocyte volume had been provided for blood transfusion needs; if blood determined to have been transfused inappropriately had not been given, 95 percent of all patients would have received four or fewer erythrocyte units. We conclude that physician education and quality assurance programs need to be coupled with innovative blood conservation efforts that provide the equivalent of 4 units of homologous blood to minimize blood transfusions in this setting.

Blood Loss, Surgical↗

PubMed1992

Selective surgical approach for atrioventricular reentrant tachycardia.

From September 1986 through September 1990, 60 operations were performed in 55 patients (32 male and 23 female; age, 1 to 76 years) for ablation of accessory pathways of atrioventricular reentrant tachycardia; 6 patients had additional cardiac procedures. Between September 1986 and August 1988 the initial surgical approach was exclusively epicardial with adjuvant cryoablation (EPI) in 23 patients (group 1) for a left free wall (LFW) pathway in 11, right free wall (RFW) in 3, posteroseptal (PS) in 7, and anteroseptal in 2. During September 1988 through September 1990, 32 patients (group 2) had the initial surgical approach tailored to the location of the mapped accessory pathway: endocardial approach (ENDO) for LFW in 17 and for juxtanodal pathway in 2, EPI for RFW in 3 and for PS in 9, and combined ENDO and EPI for AS in 1. There was no early or late death in either group. In group 1, 2 patients with LFW pathway had development of recurrent preexcitation in the same compartment requiring ENDO reoperation 10 and 11 months later, 1 with anteroseptal pathway needed immediate ENDO and EPI reoperation, and another with LFW, who required pericardial patch repair of a left atrial tear, had a thromboembolic stroke 2 days later. No serious complications occurred in group 2, but 2 patients with PS required reoperation before discharge for a second accessory pathway in another compartment (1 RFW and 1 LFW). Additionally, 4 patients (2 in each group) had from the beginning ablation of two pathways in different compartments. On complete late follow-up (mean, 28 months) all patients are back to preoperative levels of activity and are free of preexcitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Strategies in the surgical treatment of malignant ventricular arrhythmias. An 8-year experience.

Introduction of the automatic implantable cardioverter defibrillator (AICD) has dramatically affected the surgical treatment of malignant ventricular tachyarrhythmias. The authors continue to perform electrophysiologically directed subendocardial resection (SER) of left ventricular (LV) scars in selected patients, and we revascularize (CABG) those patients undergoing AICD implantation who have significant myocardial ischemia. In an attempt to define the optimal role of each procedure, this report analyzes our 8-year experience with 348 consecutive patients treated surgically for these arrhythmias (SER since 1983 and AICD since 1986). All patients undergoing SER had organized ventricular tachycardia (VT) as a result of myocardial infarction, and most had LV aneurysms; of those undergoing AICD or AICD/CABG, 60% had VT, 15% had ventricular fibrillation, and 25% had both or were noninducible. The thirty-day mortality rate was 1.5% (3/197) for AICD, 5.4% (5/93) for AICD/CABG, and 8.6% (5/58) for SER; these mortality figures are not significant different. Late deaths in all groups were predominantly due to congestive heart failure, and actuarial survival as well as freedom from sudden death was similar between the groups at 4 years. Recurrent VT occurred in 167 of 282 (59%) of long-term survivors of AICD or AICD/CABG during follow-up and in nine of 53 (17%) of those with SER. Forty-eight per cent of survivors of AICD or AICD/CABG required antiarrhythmic medications, whereas only 11% of those with SER required antiarrhythmics. Long-term survival in each group is much higher than that reported for comparable patients with severe LV dysfunction treated medically. In those patients with organized VT and LV aneurysm who are judged able to survive the procedure, SER offers a high likelihood of cure rather than simple prevention of sudden death.

Actuarial Analysis↗

PubMed1992

Selective stimulation of parasympathetic nerve fibers to the human sinoatrial node.

BACKGROUND: In animals, parasympathetic nerve fibers that innervate the sinoatrial node can be selectively stimulated to increase atrial cycle length. These nerve fibers course through an epicardial fat pad at the margin of the right superior pulmonary vein, the superior vena cava, and the right atrium. We hypothesized that similar nerves exist and can be selectively stimulated in humans. METHODS AND RESULTS: Microscopic examination of fat pads excised from the margin of the right superior pulmonary vein, the superior vena cava, and the right atrium during two human autopsies revealed the presence of nerve fibers and ganglia. We electrically stimulated this epicardial fat pad in 16 patients during cardiac surgery. The fat pads were stimulated with continuous-pulse trains for 15 seconds via a hand-held bipolar electrode using constant current (10-15 mA), constant pulse width (0.02-0.05 msec), and at 6.6, 10, 20, 25, and 30 Hz. The mean atrial cycle length +/- 1 SEM increased from 734 +/- 34 msec at baseline to a maximum of 823 +/- 61 msec at 6.6 Hz, 1,167 +/- 125 msec at 10 Hz, 1,734 +/- 281 msec at 20 Hz, 2,993 +/- 661 msec at 25 Hz, and 2,461 +/- 668 msec at 30 Hz during nerve stimulation. Linear regression analysis showed that the response of atrial cycle length to sinoatrial parasympathetic nerve stimulation was frequency dependent. The maximum response and complete decay of the response occurred within 4-8 seconds of initiation or termination of sinoatrial parasympathetic nerve stimulation. Atrioventricular conduction time and the PR interval did not change during sinoatrial parasympathetic nerve stimulation, even when the atria were paced at the baseline heart rate. CONCLUSIONS: Electrical stimulation of parasympathetic nerve fibers in a fat pad near the sinoatrial node increased atrial cycle length without affecting atrioventricular nodal conduction. This is the first study in which such nerve fibers that innervate the sinoatrial node have been selectively stimulated in humans.

Adipose Tissue↗

PubMed1991

Electrocardiographic body surface potential mapping in the Wolff-Parkinson-White syndrome. Noninvasive determination of the ventricular insertion sites of accessory atrioventricular connections.

BACKGROUND: A reliable, noninvasive procedure to determine the location of accessory atrioventricular connections in patients with Wolff-Parkinson-White syndrome would add an important diagnostic tool to the clinical armamentarium. METHODS AND RESULTS: Body surface potential mapping (BSPM) using 180 electrodes in various-sized vests and displayed as a calibrated color map was used to determine the ventricular insertion site of the accessory atrioventricular (AV) connections in 34 patients with Wolff-Parkinson-White syndrome. Attempts were made to determine the 17 ventricular insertion sites described by Guiraudon et al. All 34 patients had an electrophysiologic study (EPS) at cardiac catheterization, and 18 had surgery so the ventricular insertion sites could be accurately located using EPS at surgery. A number of physiologic observations were also made with BSPM. CONCLUSIONS: The following conclusions were drawn: 1) BSPM using QRS analysis accurately predicts the ventricular insertion site of accessory AV connections in the presence of a delta wave in the electrocardiogram; 2) the ventricular insertion sites of accessory AV connections determined by BSPM and by EPS at surgery were identical or within one mapping site (1.5 cm or less) in all but four of 18 cases; three of the four exceptions had more than one accessory AV connection, and the other had a very broad ventricular insertion; 3) BSPM and EPS locations of the accessory AV connections correlated very well in the 34 cases despite the fact that BSPM determines the ventricular insertion site and EPS determines the atrial insertion site of the accessory AV connection; 4) as suggested by the three cases of multiple accessory AV connections, EPS and BSPM may be complementary since BSPM identified one pathway and EPS identified the other (in the case with a broad ventricular insertion, BSPM and EPS demonstrated different proportions of that insertion); 5) BSPM using ST-T analysis is very much less accurate in predicting the ventricular insertion site of accessory AV connections unless there is marked preexcitation; 6) standard electrocardiography using the Gallagher grid methodology (but with no attempt at stimulating maximal preexcitation) was not as accurate as QRS analysis of BSPM in predicting the ventricular insertion site of the accessory AV connection; however, exact comparison is hampered by the different number and size of the Gallagher and Guiraudon insertion sites; 7) BSPM using QRS analysis appears to be very accurate in predicting right ventricular versus left ventricular posteroseptal accessory AV connections; 8) typical epicardial right ventricular breakthrough, indicative of conduction via the specialized AV conduction system, occurs in all patients with left ventricular free wall accessory AV connections; 9) epicardial right ventricular breakthrough was not observed in cases with right ventricular free wall or anteroseptal accessory AV connections; 10) epicardial right ventricular breakthrough can occur in the presence of posteroseptal accessory AV connections, whether right or left ventricular; and 11) the delay in epicardial right ventricular breakthrough in cases with left ventricular insertion may provide a marker to estimate the degree of ventricular preexcitation.

Adult↗

PubMed1990

Evolving patterns in the surgical treatment of malignant ventricular tachyarrhythmias.

The advent of the automatic implantable cardioverter defibrillator (AICD), generally viewed as a safe and effective intervention, has in some measure discouraged the use of electrophysiologically directed endocardial resection for intractable ventricular arrhythmias. We reviewed the records of 127 patients undergoing either AICD procedures or resection over a 6-year period. Thirty-day mortality was 5.6% (5/89 patients) for all AICD procedures, 10.7% (3/28) for AICD placement plus coronary artery bypass grafting, and 11.8% (4/34) for resection. These mortality figures are not significantly different. Patients undergoing resection were less likely to require antiarrhythmic agents than patients given an AICD (33% versus 61%). Survival at 2 years was 78% in the resection group and 72% in the AICD group. Survival at 4 years was still 78% in the resection group. Only 1 late sudden death occurred in the AICD group and none in the resection group. We conclude that resection continues to be a valuable alternative, offering a greater overall benefit at only slightly increased risk.

Adolescent↗

PubMed1990

Hemodynamic response to pumpless extracorporeal membrane oxygenation.

Respiratory support by means of arteriovenous extracorporeal membrane oxygenation driven by systemic arterial pressure, in contrast to pump-driven venoarterial extracorporeal membrane oxygenation, is attractive because of its simplicity and lack of trauma to formed blood elements. Although arteriovenous extracorporeal membrane oxygenation has been shown to improve arterial blood gases, useful levels of arteriovenous extracorporeal membrane oxygenation shunt flow may exert detrimental effects on systemic and pulmonary hemodynamics. Therefore the hemodynamic consequences of arteriovenous extracorporeal membrane oxygenation were studied in 11 dogs that were anesthetized, heparinized, and their lungs mechanically ventilated (FIO2 = 0.21) before and after induction of oleic acid pulmonary edema. The data indicate that arteriovenous extracorporeal membrane oxygenation shunt flows adequate to improve arterial blood gases resulted in significant changes in peripheral vascular resistance (-46%; p less than 0.05), systemic arterial blood pressure (-20%; p less than 0.05), and cardiac output (+110%; p less than 0.05). Dopamine infusion (5 micrograms/kg/min) proved to be more effective than volume expansion (15 ml/kg) in maintaining cardiac output, arterial blood pressure, and arterial blood gases. We conclude that pumpless arteriovenous extracorporeal membrane oxygenation, at flow rates adequate for respiratory support, can adversely alter systemic hemodynamics. However, these effects can be beneficially modulated by a moderate dose of inotropic medication.

Animals↗

PubMed1989

Survival of a recipient of renal transplantation after pulmonary phycomycosis.

A 48-year-old nondiabetic man maintained on prednisone, azathioprine, and cyclosporine after cadaveric renal transplantation developed multiple unilateral phycomycotic pulmonary abscesses. Despite treatment with amphotericin B the patient remained febrile. Surgical resection of these pulmonary abscesses was performed and the patient remains free of disease 1 year after operation. To our knowledge, this patient represents the first reported case of pulmonary phycomycosis in a recipient of renal transplantation without diabetes mellitus.

Humans↗

PubMed1988

Effect of blood transfusion on antigen presentation function and on interleukin 2 generation.

To study the effect of blood transfusion (BT) on cell-mediated immunity, we examined the antigen presentation function of peritoneal macrophages and interleukin 2 (IL-2) generation by splenocytes. C3H/HEJ mice were transfused with 0.2 mL of fresh allogeneic blood obtained from C57BL/6 mice; they were killed on days 1, 3, and 7 after BT. A second group of C3H/HEJ mice was transfused with 0.2 mL/d of the same allogeneic blood on three successive days; they were killed on day 7 following the last BT. The antigen presentation function of peritoneal macrophages was measured by utilizing a D10.G4.1 T-helper cell clone; IL-2 activity in supernatants of concanavalin A-stimulated splenocytes was tested by utilizing an IL-2-dependent HT-2 cell line. The results indicate that although antigen presentation function remains unaffected after single and multiple BTs, the ability of splenocytes to generate IL-2 decreases significantly even after a single BT. Thus, the increased susceptibility to infection and the additional immune perturbations in malignant neoplasms following BT may be due in part to decreased IL-2 generation.

Animals↗

PubMed1987

Hemorrhage without tissue trauma produces immunosuppression and enhances susceptibility to sepsis.

To determine whether hemorrhage without major tissue trauma can itself produce immunosuppression, the effect of hemorrhage on the lymphocyte response to T-cell mitogen in endotoxin-resistant C3H/HEJ mice was measured. The mice were bled to achieve a mean blood pressure of 35 mm Hg, maintained at that level for one hour, and then adequately resuscitated. On days 1 through 10 thereafter, the proliferative responses of the splenocytes to concanavalin A were measured and allogeneic mixed lymphocyte reaction was performed. The proliferative responses to mitogen stimulation as well as the results of mixed lymphocyte reaction studies indicated that marked immunosuppression occurred at day 1. Immunosuppression persisted for at least five days following hemorrhage, as evidenced by mitogen stimulation assay. Another group of mice was subjected to sepsis three days after hemorrhage and resuscitation. The mortalities in the sham-hemorrhage and hemorrhage groups following sepsis were 58% and 100%, respectively. Thus, a significant depression of cellular immunity occurred following simple hemorrhage despite adequate resuscitation, and this immunosuppression enhanced the susceptibility to sepsis.

Animals↗