Biomedical subjects

A J Acinapura

Publications and source records attributed to A J Acinapura.

At least 19 recordsLinked to original sources

PubMed2001

A cytokine analysis of the effect of cell saver on blood in coronary bypass surgery.

BACKGROUND: Increasing concern about the transmission of viral disease has generated greater interest in the use of salvaged blood as a means of alleviating the demand for homologous blood and expediting resuscitation during massive hemorrhage. Autologous blood processed by autotransfusion devices has become increasingly common in major surgery and is now largely viewed as safe and efficacious. However, there may be serious complications and sequelae associated with the use of processed blood, such as adult respiratory distress syndrome (ARDS) and renal failure. Complement cascade activation resulting from blood coming into contact with autotransfusion equipment leads to enrollment of leukocytes and release of large concentrations of cytokines, which may contribute to the development of organ failure. Our study evaluated cytokine release during cell saver (CS) blood salvage in the course of coronary artery bypass grafting (CABG) surgery. MATERIALS AND METHODS: Forty-five patients randomly selected for CABG were evaluated. All had received at least one unit of autotransfused blood by means of the Haemonetics Cell Saver System 5 (Haemonetics Corp., Braintree, MA). Each patient had four blood samples taken (pre-operative, CS container, autotransfusion from the blood bag, and one hour post-transfusion). These samples were then centrifuged and the sera were collected. An enzyme linked immunosorbent assay (ELISA) test, using the Biosource Cytoscreen solid phase "sandwich" ELISA kit (Biosource International, Camarillo, CA) was conducted to determine levels of the cytokines Interleukin (IL) 1, 2, 4, 6, 8, and 10, tumor necrosis factor (TNF), intracellular adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM). RESULTS: Significantly increased concentrations of the pro-inflammatory cytokines IL-1, 2, 4, 6, and 8, TNF, ICAM, and VCAM were noted throughout all time periods studied. The same effect was observed for the anti-inflammatory cytokine IL-10. CONCLUSION: Statistically significant increases in both the circulating levels of the pro-inflammatory and anti-inflammatory cytokines studied were recorded. It is our contention that the presence of IL-10, a down-regulator of inflammation, is responsible for attenuating the possible deleterious effects of the pro-inflammatory cytokines observed. However, morbidity and mortality, as well as the future patency of the bypass grafts, have not been correlated with the use of the autologous method of transfusion.

Adult↗

PubMed2001

A comparative study of endothelial cell injury during open and endoscopic saphenectomy: an electron microscopic evaluation.

BACKGROUND: The role of damaged endothelium in early graft occlusion has been extensively demonstrated. Seventy percent of early graft occlusions in coronary artery bypass were caused by thrombi overlying areas of endothelial loss. With the increased use of endoscopic vein harvesting, it becomes important to study the extent of endothelial damage by light and electron microscopy. In this study, we compared the degree of endothelial damage inflicted by the open and endoscopic techniques of vein harvesting using light, scanning, and transmission electron microscope. MATERIAL AND METHODS: Ninety samples of saphenous veins from 45 patients prepared for coronary artery bypass grafting (CABG) utilizing both endoscopic and standard open incision techniques were examined using light, scanning, and transmission electron microscopy. These vein samples were prepared in Plasma-lyte solution (Baxter) in combination with or without papaverine, at two distending pressures of 100 or 300 mmHg and at temperatures of either 4 degrees C or 28 degrees C in eight subgroups and one control group. The pathological alterations in the saphenous veins were graded either based on a scoring system (0 = none, 1 = < 10%, 2 = 10-25%, 3 = 25-50%, 4 = > 50%) to assess the degree of damage inflicted by these two different types of saphenectomies or by electron microscopic observed abnormalities, including endothelial cell (EC) separation, EC detachment, basement membrane (BM) exposure, collagen exposure, and EC edema. RESULTS: Using cross-tabulation and Chi-square statistical analysis, we found that the differences in the degree of endothelial damage using either of the techniques is not statistically significant (P > 0.05). CONCLUSION: Our findings indicate that endoscopic and open saphenectomies are technically comparable as far as structural damage is concerned, rendering the endoscopic technique of vein handling the preferred method for CABG.

Chi-Square Distribution↗

PubMed2000

Intercellular and vascular cell adhesion molecule levels in endoscopic and open saphenous vein harvesting for coronary artery bypass surgery.

BACKGROUND: Numbers of intercellular and vascular cell adhesion molecules (ICAM and VCAM) and major ligands on endothelial cells for adherence of activated polymorphnuclear leukocytes, macrophages, and lymphoid cells increase in many inflammatory disorders and after trauma to different tissues. METHODS: Samples of human saphenous veins were harvested from 90 randomly selected patients who underwent coronary artery bypass graft (CABG) surgery, utilizing two different techniques (open and endoscopic). Endothelial cells were collected from the vein samples and cultured for 72 hours. Pre- and postoperative sera, in addition to the supernatants from the cultures, were analyzed for ICAM-1 and VCAM-1 using enzyme-linked immunosorbent assay. RESULTS: Mean preoperative levels of ICAM-1 and VCAM-1 (0.95 +/- 0.58 ng/mL and 1.81 +/- 1.03 ng/mL, respectively) did not differ significantly from that of postoperative sera (0.98 +/- 0.451 ng/mL and 1.74 +/- 1.05 ng/mL, respectively) (p = 0.77 and p = 0.73, respectively). Mean ICAM-1 and VCAM-1 levels in endothelial cell culture supernatants did not differ significantly between the endoscopic (0.16 +/- 0.05 ng/mL and 0.23 +/- 0.10 ng/mL, respectively) and the open method (0.18 +/- 0.08 ng/mL and 0.30 +/- 0.27 ng/mL, respectively) (p = 0.19 and 0.13, respectively). CONCLUSION: Our findings indicate that endoscopic and open saphenectomies are technically comparable in their effects on ICAM-1 and VCAM-1 synthesis during saphenous vein harvesting for CABG. We recommend the endoscopic method for its low morbidity and earlier hospital discharge.

Angioscopy↗

PubMed1999

Studies in thoracic aortic graft infections: the development of a porcine model and a comparison of collagen-impregnated dacron grafts and cryopreserved allografts.

OBJECTIVE: A porcine model of thoracic aortic graft infection was created, and various anatomic sites and the timing of inoculation of the graft to induce infection were investigated. Ultimately, the ability of cryopreserved allograft to resist infection was compared with that of collagen-impregnated Dacron graft. METHODS: Yorkshire pigs (n = 16) underwent placement of an expanded polytetrafluoroethylene patch graft in the ascending aorta and the left atrial appendage (phase I). Eight animals were immediately given a 50-mL bolus (1 x 10(8) cfu/mL) of Staphylococcus aureus whereas the other 8 received the infusion 24 hours later. Animals were put to death 8 weeks later and the grafts were sterilely explanted and analyzed via microbiologic culture and standard histologic procedures for evidence of infection. The results displayed that the aortic graft and a delay of induced bacteremia of 24 hours were more reliable methods of producing infection. During phase II, 13 pigs were randomized to receive either a collagen-impregnated Dacron graft (n = 6) or a cryopreserved allograft (n = 7) in the ascending aortic position only and infusion of S aureus 24 hours after the operation. The experiment then proceeded to completion. RESULTS: Phase I results displayed that use of an aortic graft and induced bacteremia 24 hours after the operation was a more reliable and reproducible method of producing infection. In phase II, graft infection was present in 38.5% (5/13) of animals, with only 16.7% (1/6) in the collagen-impregnated Dacron graft group and 57.2% (4/7) in the cryopreserved allograft group becoming infected. There was no significant difference between the collagen-impregnated Dacron graft and cryopreserved allograft groups in the incidences of thoracic aortic graft infections (P =.27, Fisher exact test). CONCLUSIONS: This novel porcine model of thoracic aortic graft infection is a reproducible method for the investigation of thoracic aortic graft infections. The phase I study investigated the timing of the induced bacteremia and the most susceptible position of a graft. Phase II demonstrated that collagen-impregnated Dacron grafts are equivalent, if not superior, to cryopreserved allografts in resisting central vascular graft infections in the ascending aorta.

Animals↗

PubMed1998

The efficacy of left atrial to femoral artery bypass in the prevention of spinal cord ischemia during aortic surgery.

Surgical repair of traumatic lesions or aneurysmectomy of the descending thoracic aorta necessitates the interruption of distal aortic blood flow, a situation which invariably promotes proximal hypertension accompanied by a precipitous increase in cerebrospinal fluid pressure and distal hypoperfusion. All are significant determinants of postoperative paraplegia. The institution of aortic bypass, distal to cross-clamping, by either implantation of an extraluminal passive shunt or deployment of left atrial to femoral artery (LA-FA) cannulation with a centrifugal pump, is the most widespread modality to afford a means of proximal decompression and provide distal perfusion. Passive shunt techniques do not consistently provide optimal bypass efficiency, due to inherent limitations of device design and the inability to accurately monitor and control flow. The LA-FA bypass technique is superior to passive shunts in effecting proximal unloading by allowing for precise adjustment of blood flow to equilibrate proximal and distal aortic pressures. The concomitant use of cerebrospinal fluid drainage with LA-FA bypass can effectively reduce the incidence of postoperative paraplegia. Intraoperative monitoring of evoked potentials as a sensitive indicator of spinal cord ischemia should be considered an integral component of preserving cord function. The use of cerebrospinal fluid drainage and evoked potential monitoring in conjunction with LA-FA bypass is therefore highly advisable.

Aorta, Thoracic↗

PubMed1998

Nonsurgical pneumoperitoneum: a case report and a review.

The finding of extraluminal gas on plain radiographs is usually associated with a perforated viscus. But, as this case shows, the finding of pneumoperitoneum is not pathogenic of a perforated viscus or even of a surgical emergency, because there are many benign explanations for a pneumoperitoneum. Perhaps the most important maneuver for differentiating between the two is by performing a through history and physical examination. This in conjunction with either a diagnostic peritoneal lavage, contrast studies, or endoscopic evaluation can help prevent a patient from having needless surgery. The causes of a nonsurgical pneumoperitoneum are described as well as a treatment plan for patients presenting with a nonsurgical pneumoperitoneum.

Abdomen, Acute↗

PubMed1994

Effect of cerebrospinal fluid drainage and/or partial exsanguination on tolerance to prolonged aortic cross-clamping.

Paraplegia as a consequence of spinal cord ischemia associated with procedures on the thoracic and thoracoabdominal aorta has been linked to the interaction of proximal hypertension with elevated cerebrospinal fluid pressure (CSFP) during aortic cross-clamping (AXC). CSFP reduction via cerebrospinal fluid (CSF) drainage is thought to significantly prolong the cord's tolerance to AXC. Likewise, partial exsanguination is reported to effectively reduce ischemic injury by controlling proximal hypertension. To evaluate the individual and collective efficacy of both techniques, 18 mongrel dogs (25 to 35 kg), divided into three equal groups, underwent a fourth interspace left thoracotomy AXC. Baseline proximal arterial blood pressure (PABP), distal arterial blood pressure (DABP), and CSFP were established and monitored at 5-minute intervals during 120 minutes of AXC, and for 30 minutes thereafter. Group I animals were partially exsanguinated prior to AXC to maintain PABP at a mean of 115 to 120 mmHg. Group II animals had sufficient (16 +/- 5 cc) CSF withdrawn to maintain a DABP-CSFP gradient, i.e., spinal cord perfusion pressure (SCPP) of 20 mmHg. Group III animals were treated with both CSF drainage and partial exsanguination in the same manner as groups I and II, respectively. Perioperative somatosensory evoked potential (SEP) monitoring evaluated cord function. Postoperative neurological outcome was assessed with Tarlov's criteria. SEPs degenerated approximately 22 minutes following AXC for groups II and III. In contrast, group I exhibited rapid (10 +/- 7 min) SEP loss. All five surviving group I animals displayed paralysis 48 hours postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Outcome of patients with abnormal ocular pneumoplethysmographic measurements undergoing coronary artery bypass grafting.

A total of 1780 patients without symptoms of cerebral ischemia undergoing coronary artery bypass grafting (CABG) were screened before surgery for carotid stenosis by pneumophlethysmography. An abnormal test was defined as a difference in ophthalmic artery pressures of > or = 5 mmHg or ophthalmic-brachial pressure index < or = 0.69. Some 99 patients (5.6%) had an abnormal ocular pneumoplethysmographic measurement (89 unilateral, ten bilateral). Of these, 26 patients underwent prophylactic carotid endarterectomy before CABG (group 1), while the remaining 73 patients had reconstruction without previous carotid endarterectomy (group 2). A total of 100 patients (group 3) with normal ocular pneumoplethysmographic results were used as controls. The three groups were comparable with respect to age, diabetes, hypertension, smoking and severity of coronary artery disease. Early (30-day) postoperative stroke rates were 0 and 4% (n = 3) for groups 1 and 2 respectively, and 0% for group 3 (P > 0.07). Early mortality rates after CABG for groups 1 and 2 were 4% (n = 1) and 1% (n = 1), respectively and 2% (n = 2) for groups 3 (P > 0.4). Late follow-up (mean 48 months) demonstrated stroke rates of 0% for group 1, and 10% and 4% for groups 2 and 3 (P > 0.08). The early mortality and stroke rates in the ten patients with bilateral abnormal ocular pneumoplethysmographic values were 0 and 0%. However, late strokes occurred significantly more often (43%) in patients with bilateral abnormal results compared with those with unilateral abnormal findings when both groups did not undergo carotid endarterectomy (P < 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Pleural liposarcoma presenting with respiratory distress and suspected diaphragmatic hernia.

A young woman with a history of diaphragmatic hernia presented to the hospital in respiratory distress and in premature labor. Her admission chest roentgenogram showed opacification of the left hemithorax, and her arterial blood gas analysis revealed hypoxemia. Emergency cesarean section and exploratory left thoracotomy were carried out; a large tumor occupied the left side of the chest, and pneumonectomy was performed. No diaphragmatic hernia was present. A pathologic diagnosis of primary liposarcoma was made.

Adult↗

PubMed1990

Cerebrospinal fluid drainage and steroids provide better spinal cord protection during aortic cross-clamping than does either treatment alone.

We investigated whether intravenous methylprednisolone (30 mg/kg) before 30 minutes of aortic cross-clamping and after 4 hours could enhance the effects of cerebrospinal fluid drainage on spinal cord perfusion pressure and postoperative paraplegia when proximal blood pressure was controlled with sodium nitroprusside and partial exsanguination. Dogs were randomized into three groups: group 1 (n = 6), control; group 2 (n = 7), steroids; and group 3 (n = 6), steroids with cerebrospinal fluid drainage. During aortic cross-clamping, blood pressure proximal to the clamp decreased significantly in each group compared with baseline (p less than 0.05), but did not differ among groups (group 1 = 82.2, group 2 = 82.1, group 3 = 86.6 mm Hg, p greater than 0.05). Mean distal pressure decreased from systemic values to 8.4, 8.5, and 3.7 mm Hg, respectively, after aortic cross-clamping (p less than 0.05); these values did not differ from one another (p greater than 0.05). During aortic cross-clamping, cerebrospinal fluid pressure in groups 1 and 2 did not differ significantly compared with baseline (12.2 versus 8.2, 14.2 versus 10.7 mm Hg, p greater than 0.05), whereas in group 3 the baseline cerebral spinal fluid pressure of 10.7 mm Hg decreased to 0.4 mm Hg (p less than 0.05). Spinal cord perfusion pressure in group 3 was significantly higher than in groups 1 and 2 (3.3 versus -3.9 and -5.7 mm Hg, p less than 0.05), but did not differ between groups 1 and 2 (p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Esophageal perforation in a patient with acquired immunodeficiency syndrome.

Infection with Mycobacterium tuberculosis is frequently found in patients with acquired immunodeficiency syndrome and can result in diffuse lymphadenopathy from disseminated disease. A case is presented of esophageal erosion and perforation secondary to mediastinal lymph node enlargement from Mycobacterium tuberculosis in a patient positive for human immunodeficiency virus. Emergent surgical intervention required resection of the perforated esophagus, end-cervical esophagostomy, gastrostomy, and feeding jejunostomy. Long-term prognosis is poor owing to acquired immunodeficiency syndrome, therefore, reconstruction at a later date is uncertain.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Demographic changes in coronary artery bypass surgery and its effect on mortality and morbidity.

Over the past 4-5 years, possibly with the advent of percutaneous transluminal coronary angioplasty (PTCA), there has been a changing patient population for coronary artery bypass surgery (CABS) with a gradual increase in the operative mortality. In an attempt to analyze the changing demographics in patients undergoing CABS and its effect on operative mortality, we analyzed data from 5536 consecutive patients undergoing isolated CABS. There was 4151 patients less than 70 years of age and 1385 patients greater than 70 years. Reoperative CABS procedures were performed in 385 patients, and CABS for post infarction unstable angina pectoris was performed in 578 patients. During the same time period, 2910 patients underwent PTCA. The mean age of bypass patients was 68.5 years with 38% being 70 years or older. The left ventricular ejection fraction in patients undergoing CABS averaged 38%. The average number of bypasses performed was 3.1. In comparison, patients presenting for PTCA were younger (average age 55), had normal ejection fractions (average 55%) and were predominantly treated for single or double vessel disease. The hospital mortality for elective CABS in patients less than 70 years of age was 1.8%, for reoperative CABS 3.6%, for post infarction unstable angina pectoris 4%, and for patients greater than 70 years 8%, for a combined operative mortality of 4.8%. These data suggest that because of the increasing number of elderly patients (greater than 70 years of age), and the increasing number of reoperative CABS cases and acute myocardial infarction patients with unstable angina pectoris presenting for CABS, the operative mortality will continue to rise.

Adult↗

PubMed1989

Internal mammary artery bypass grafting: influence on recurrent angina and survival in 2,100 patients.

Internal mammary artery (IMA) bypass grafting to the anterior descending coronary artery was performed in 2,100 patients between January 1978 and July 1986. The average number of additional saphenous vein grafts (SVGs) per patient was 1.8. During the same period, 1,753 patients underwent coronary artery bypass grafting using an SVG (average number of grafts per patient, 3.2). The average patient age was similar: 62.3 years for IMA grafts and 64.7 years for SVGs. Men constituted two thirds of each group. Left ventricular function was impaired (ejection fraction less than 45%) in 1,071 (51%) of IMA grafts and 847 (48.3%) of SVGs. Other aggregate risk factors, ie, elevated blood pressure, diabetes mellitus, previous myocardial infarction, and congestive heart failure, were similar in each group. Operative results and postoperative mortality of the IMA and SVG patients were comparable. However, the long-term probability of cumulative survival and occlusion-free survival were significantly greater and the probability of recurrent angina and reoperative coronary artery bypass grafting were significantly less in IMA graft patients (p less than 0.015). The relative risk of occlusion in an SVG was 4 to 5 times greater than that of the IMA graft. These data indicate that a patent IMA graft to the anterior descending coronary artery protects against recurrent angina and death from cardiac-related causes, and that the IMA should be the conduit of choice.

Adult↗

PubMed1989

Effect of sodium nitroprusside on spinal cord perfusion and paraplegia during aortic cross-clamping.

To evaluate the effects of sodium nitroprusside (SNP) on hemodynamics, cerebrospinal fluid dynamics, and neurological outcome after 30 minutes of thoracic aortic occlusion, we monitored proximal and distal blood pressure, cerebrospinal fluid pressure, spinal cord blood flow, and somatosensory evoked potentials. In group 1 (n = 6), no attempts were made to control proximal hypertension, whereas in group 2 (n = 6), proximal blood pressure was controlled with intravenous infusion of SNP. There was no significant difference in proximal or distal blood pressure or cerebrospinal fluid pressure between the two groups at baseline. During the crossclamp interval, the mean proximal aortic pressure rose from 108 +/- 21 to 146 +/- 14 mm Hg (p less than 0.001) in the control group, whereas the mean blood pressure in the SNP group was maintained at 99.8 +/- 12 mm Hg (p = not significant compared with baseline blood pressure). Mean distal aortic pressure decreased from systemic values to 23 +/- 7 mm Hg in control animals and to 11 +/- 5 mm Hg in the SNP group (p less than 0.005). In the latter group, cerebrospinal fluid pressure increased significantly from 10.6 +/- 1.9 to 20.1 +/- 5.5 mm Hg (p less than 0.005). In animals receiving SNP, spinal cord blood flow was decreased in the lower spinal cord segments and increased in the upper cord segments. When compared with controls, this difference did not reach significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Internal mammary artery bypass: effect on longevity and recurrent angina pectoris in 2900 patients.

Internal mammary artery bypass (IMA) to the anterior descending coronary artery was performed in 2900 patients from January 1978 to December 1987. The average age of the patients was 64 years. Males accounted for 68% (1972 patients) and 82% (2378 patients) were in New York Heart Association (NYHA) class III. Left ventricular function was impaired in 51%. The average number of additional saphenous vein grafts per patient was 1.8. The operative mortality was 1.6%. Mediastinitis occurred in 29 patients (1%). Reoperation for bleeding was necessary in 32 patients (1.1%). Perioperative myocardial infarction (MI) was seen in 58 patients (2%) and neurological complications occurred in 32 patients (1.1%). Repeat coronary angiography was performed in 703 patients (25%) and demonstrated a patency rate of 96% in IMA grafts and 81% in saphenous vein grafts (SVG). Survival at 9 years was 90% from all causes and 95% when noncardiac deaths were excluded. Recurrence of angina occurred in 522 patients (18%) and reoperation was performed in 15 patients (0.5%). During the same time period, 1783 patients underwent coronary artery bypass utilizing a SVG. Survival at 9 years was 78% from all causes and 83% when noncardiac deaths were excluded. Recurrent angina was present in 546 patients (39%). These data suggest that a patent-IMA to the anterior descending protects against recurrent angina and death from cardiac causes and should be the conduit of choice.

Angina Pectoris↗

PubMed1988

Coronary artery bypass in septuagenarians. Analysis of mortality and morbidity.

Elective coronary artery bypass surgery can be performed with an expected operative mortality of 1-3%. However, the effects of age on morbidity and mortality in patients undergoing this procedure remain controversial. To analyze morbidity and mortality in septuagenarians undergoing isolated coronary artery bypass surgery, we compared the results in 685 septuagenarians with those in 3,142 patients under the age of 70 years, all of whom underwent this procedure from January 1981 to December 1986. A larger percentage of elderly patients had triple-vessel disease (89% vs. 71%), left main coronary artery obstruction (34% vs. 16%), and ejection fractions less than 45% (68% vs. 41%). A larger percentage of septuagenarians had perioperative myocardial infarction (8% vs. 2%), required prolonged ventilatory support (10% vs. 3%), and had major neurological complications (4% vs. 1%). Mortality rates were significantly higher in elderly patients (7% vs. 2%) but did not correlate with the severity of coronary artery disease, the anginal pattern, or the diminishment of ventricular function. Major causes of mortality were pulmonary failure, renal failure, or both, sepsis, and neurological complications. These data suggest that elderly patients have an increased risk of cardiac and noncardiac morbidity and mortality after coronary artery bypass surgery. Higher mortality rates in this age group appear attributable to noncardiac organ failure. Late follow-up studies failed to show any significant difference among patients based on age alone.

Aged↗

PubMed1988

In vitro bursting strength studies of laser-welded tissue and comparison with conventional anastomosis.

We compared the mechanical integrity of microvascular anastomoses created with a carbon dioxide (CO2) laser with conventional suture anastomoses. Seventy rat femoral artery segments (35 lased and 35 sutured) were harvested at 1, 24, and 72 hours, and 1, 3, 6, and 12 weeks postoperatively. These segments were subjected to increasingly higher in vitro intraluminal hydrostatic pressures (bursting pressure). Conventionally sutured anastomoses exhibited significantly increased ability (p less than 0.05) to withstand greater bursting pressures than the laser-welded tissue up to 3 weeks postoperatively. After the third postoperative week, the laser anastomoses demonstrated increased bursting pressures compared with the conventional anastomoses. At the end of the 12-week period both groups demonstrated an ability to withstand supraphysiologic pressures in excess of 2000 mm Hg.

Anastomosis, Surgical↗

PubMed1988

Somatosensory evoked potentials and spinal cord perfusion pressure are significant predictors of postoperative neurologic dysfunction.

Paraplegia after thoracoabdominal aneurysm repair can occur in 3% to 40% of patients. This study investigated the efficacy of cerebrospinal fluid (CSF) drainage to protect the spinal cord during aortic cross-clamping (AXC) and the interrelationship between drainage, spinal cord perfusion pressure (SCPP), and changes in somatosensory evoked potentials (SEP) in a canine model of spinal cord ischemia. SCPP was defined as the mean distal aortic pressure minus the CSF pressure. In the experimental group, CSF was drained before AXC. SEP changes were quantitated as time to latency increase of 10% (L-10) and time to complete SEP loss. Drainage of CSF had no significant effect on the distal aortic pressure but significantly increased SCPP from 9.4 to 21.8 mm Hg and decreased the incidence of postoperative neurologic injury. Ischemic SEP changes were highly significant predictors of postoperative neurologic injury, occurring more than two times earlier in the paralyzed and paraparetic animals. Dogs without neurologic injury had significantly higher SCPP, delayed L-10 time, and delayed SEP loss.

Animals↗