Transcutaneous oxygen measurements predict a beneficial response to hyperbaric oxygen therapy in patients with nonhealing wounds and critical limb ischemia.

Hyperbaric oxygen (HBO) therapy may be a useful adjunct in the treatment of patients with wounds associated with critical limb ischemia. These patients either cannot undergo a successful bypass or may not heal after vascular reconstruction alone. Identification of patients likely to benefit from HBO is essential before treatment, as this therapy is time-consuming, costly, and not without risk. Transcutaneous oxygen measurements (TCOM) can be used to evaluate the degree of hypoxia in ischemic tissue. In this study we evaluated whether TCOM could be used to identify those patients who would or would not benefit from HBO therapy. Our hypothesis is that a difference in transcutaneous oxygen tension readings measured near the ischemic lesion with the patient breathing room air and while breathing 100 per cent oxygen at ambient pressure may be predictive of wound healing with adjunctive hyperbaric oxygen therapy. Thirty-six patients with critical limb ischemia and nonhealing ulcers were referred for HBO therapy. They were deemed either nonreconstructible from a vascular surgical viewpoint, had failed prior revascularization attempts, or could not achieve complete wound healing even after a successful revascularization. Pretreatment assessment included a room air and post-100 per cent-O2 challenge TCOM reading obtained in the vicinity of the open wound. Hyperbaric oxygen treatments at 2.0 to 2.5 atm were then administered until healing occurred or failure was confirmed. All patients undergoing HBO had a baseline TCOM of <40 torr. Twenty-seven patients had an increase in TCOM of >10 torr with oxygen inhalation at initial evaluation. Of these patients, 19 (70%) healed their wounds with HBO therapy. Conversely the increase in TCOM was <10 torr in nine patients, and only one of these patients (11%) ultimately healed (P < 0.01). Patients with nonhealing ischemic extremity wounds may heal with adjunctive HBO therapy. We can predictably identify patients who are likely to benefit from this modality using TCOM at the time of initial evaluation. An increase of tissue O2 tension of > or =10 torr when breathing pure O2 suggests that the patient may benefit from HBO therapy. Those patients with an increase of <10 torr are unlikely to receive benefit from this treatment modality.

Supervised training of general surgery residents in carotid endarterectomy performed on awake patients under regional block is safe and desirable.

Previous studies have documented the safety and efficacy of general surgery residents and vascular fellows performing carotid endarterectomy (CEA) under the supervision of an attending surgeon. With the proper supervision of the attending surgeon, these operations can be performed with an acceptably low perioperative stroke and mortality rate. The question remains, however, whether these desirable results can be obtained by general surgery residents when operating on awake patients under regional block (RB) anesthesia. We set out to determine whether it is prudent to promote this technique in this teaching setting. We analyzed 128 CEAs performed at a community teaching hospital training three chief residents a year. These operations were performed by residents under the direct supervision of a single attending vascular surgeon. RB was preferred and was used in 67 operations. General anesthesia (GA) was used in the remaining 61 procedures. Overall mortality was 0 per cent. Patients in the RB group were converted intraoperatively to GA in 4 of 67 (6%) procedures. There was one perioperative stroke in this series (1/128, 0.78%), occurring in a patient under RB (1/67, 1.5 %) leaving the patient with a minor sensory deficit. No strokes occurred in the GA group. There were five temporary cranial nerve deficits (3.9%). Three were in the RB group (4.5%) and two in the GA group (3.3%). General surgery residents can be trained in the performance of carotid endarterectomy using regional block anesthesia in awake patients without compromising patient safety. Suggestions to the effect that only attending physicians and/or vascular fellows can perform these procedures under regional block are without merit.

Chlorhexidine lavage in the treatment of experimental intra-abdominal infection.

HYPOTHESIS: Closed postoperative peritoneal lavage (CPPL) with chlorhexidine gluconate reduces the number of intraperitoneal bacteria and improves the outcome of intra-abdominal infection. DESIGN: Laboratory animal trial. INTERVENTIONS: Intra-abdominal infection was produced in mice by the cecal ligation and puncture technique. After 16 to 18 hours, the animals underwent relaparotomy and placement of an intra-abdominal catheter for CPPL. In the first experiment animals were randomly divided into 4 groups: no lavage (served as a control), CPPL with chlorhexidine. CPPL with cefoxitin, and CPPL with lactated Ringer solution (LR). Lavage was continued intermittently every 8 hours for 24 hours. All animals received systemic cefoxitin every 8 hours for 7 days. Mortality was recorded every 8 hours for 10 days. In the second experiment, animals were divided into 3 groups: no lavage (served as a control), CPPL with chlorhexidine, and CPPL with LR. Lavage was continued intermittently every 8 hours for 24 hours. The animals were killed 48 hours after reoperation. Bacterial counts from peritoneal fluid and biopsy specimens, as well as peritoneal white blood cell counts, were measured before and after lavage. RESULTS: Closed postoperative peritoncal lavage with chlorhexidine reduced mortality from 71% in a control group to 37% (P = .003). There was no survival benefit in either the CPPL with cefoxitin (91% mortality) (P = .14) or CPPL with LR groups (90% mortality) (P = .17). The statistically significant findings of analysis of variance evaluation demonstrated a decrease in bacterial counts after cecal excision in all 3 groups. There was a greater reduction in bacterial counts in the chlorhexidine group compared with the control group (P<.05). Bacterial counts decreased in peritoneal fluid, as well as in tissue biopsy specimens, after cecal excision. White blood cell counts significantly decreased after cecal excision in all 3 groups. There was no difference in white blood cell counts between the groups. Correlation analyses demonstrated weak interaction between bacterial and white blood cell counts before or after treatment in all the groups. Pearson r ranged from -0.37 to +0.35, none of which were statistically significant. CONCLUSIONS: In our experiments chlorhexidine lavage resulted in a 50% reduction in mortality and a significant reduction in bacterial counts compared with the control group. There was no survival benefit from lavage with either cefoxitin or LR. There was no reduction in bacterial counts in the LR group relative to the control group. Thus, the survival benefit and the reduction in bacterial numbers are attributed to the antibacterial properties of chlorhexidine rather than to the mechanical washing of the abdominal cavity. Closed postoperative peritoneal lavage with 0.05% chlorhexidine gluconate might be useful in the multimodal treatment of intra-abdominal infection.

Needle-localized breast biopsy for mammographic abnormalities: a community hospital experience.

Increased awareness of benefits of early detection of breast cancer has resulted in increased numbers of screening mammographies and breast biopsies for nonpalpable lesions. Tertiary hospital studies have demonstrated positive biopsy rates from abnormal mammographic findings at 18 to 32 per cent. We examined the effectiveness of needle biopsy for nonpalpable radiographic abnormalities in our community hospital. We reviewed 167 records of patients biopsied over a 2-year period. Mammographic assessment, biopsy, and pathological assessment were performed using accepted methods. Malignancy was detected in 34 of 167 biopsies (20%). The biopsy yield rate was highest for mammographic findings of spiculated or stellate masses (75%, P < 0.01). Most biopsies (83%) were performed because of mammographic findings of microcalcifications or circumscribed enlarging masses/nodular developing densities for a positive biopsy yield rate of 16 per cent. Rates were higher in patients with personal (44%) or family history (30%) of breast cancer and in postmenopausal women (30%). These results demonstrate that 1) factors such as age, personal or family history of breast cancer, and certain mammographic features of breast lesions are associated with high biopsy yield rates, and 2) the biopsy yield rate in our community setting is comparable to tertiary hospital experience.

Persistent sciatic artery in association with varicosities and limb length discrepancy: an unrecognized entity?

The persistence of the sciatic artery is an unusual occurrence, with an angiographically demonstrated incidence of 0.06%. There have been 71 cases previously reported. We report an additional case in a 14-year-old boy who presented with a chief complaint of unsightly varices. The involved right limb was notably shorter than the uninvolved left lower extremity. Work-up included physical examination, duplex studies, venography, and angiography. Our patient was found to have a patent deep venous anatomy with valvular incompetency associated with complete persistence of the sciatic artery and a foreshortened right leg. He has done well with conservative treatment. The persistence of a sciatic artery has occasionally been associated with other anomalies including Mullerian and left renal agenesis, A-V fistula formation, hypertrophy or hypotrophy, multiple hemangiomata, neurofibromatosis, or anomalies of leg arteries. The literature describes three previous case reports in which patients presented with gross varicosities and were incidentally found to have persistent sciatic arteries as well as limb length discrepancies. Our patient is a fourth example of this syndrome. This pattern of physical attributes has not been previously described as a distinct entity. The association of venous incompetency, limb discrepancies, and persistence of the sciatic artery may be an incidental finding or may represent a related embryologic event. This relationship merits consideration in a young patient presenting with severe venous varicosities.

Symptomatic subclavian steal syndrome four decades after operation for dysphagia lusoria.

Congenital abnormalities of the aortic arch may lead to signs and symptoms of tracheal and esophageal obstruction secondary to a restrictive vascular ring. There are many case reports and monographs concerning the surgical management of dysphagia lusoria. This case provides the first example of long-term follow-up of surgical intervention for relief of dysphagia lusoria. A 45-year-old laborer presented with a several year history of episodic bilateral blindness and a more recent onset of "drop attacks." Notably this patient had presented at the age of 18 months with difficulty breathing and eating since birth. The patient also had frequent upper respiratory infections and episodes of pneumonia. Workup revealed a right-sided aortic arch with a left ligamentum arteriosum. When he was first seen in our clinic, history and physical examination revealed claudication and diminished pulses in the left upper extremity. Arteriography and duplex studies confirmed reversal of flow in the patient's left vertebral artery. The arteriogram demonstrated the presence of a right-sided aortic arch and descending aorta along with the proximal stump of the previously ligated left subclavian artery. He underwent left carotid to left axillary artery bypass for the treatment of symptomatic subclavian steal syndrome. His symptoms have resolved with return of antegrade vertebral flow and the presence of normal pulses in the left arm. Congenital aortic abnormalities that lead to tracheal and esophageal compromise are numerous and varied. Surgical management requires a thorough understanding of the person's anatomy and preoperative planning. The life expectancy of patients with dysphagia lusoria necessitates consideration of the long-term consequences of surgical intervention.

Fibromuscular dysplasia of the brachial artery: an endovascular approach.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic segmental disease of unknown etiology primarily affecting muscular arteries of intermediate size. The pathology affects the renal arteries in the majority of cases, followed by the carotid, vertebral, and ilio-femoral arteries. There have been only six reported cases of FMD involving the brachial artery. This case report describes the seventh case and illustrates an endovascular approach to this clinical entity. A 63-year-old female with a history of hypertension presented to vascular surgery clinic with a 4-day history of numbness, pain, and coolness of her left hand. On physical exam, the patient had a normal axillary and brachial pulse, but had only a Doppler signal of the left ulnar artery. There was no Doppler signal of the radial artery. Segmental pressures and PVR waveforms were normal in the upper arm, but there was a significant blunting of the waveform and decrease in pressure at the level of the wrist. An arteriogram revealed significant narrowing and irregularity of the brachial artery with a characteristic "string-of-beads" appearance. There was complete thrombosis of the radial artery and evidence of fresh thrombus in the distal brachial artery. The patient was treated with intra-arterial infusion of urokinase with restoration of the radial pulse and resolution of her symptoms. Subsequently, the patient had a percutaneous transluminal balloon angioplasty of the involved segment of brachial artery, with normal PVR's and segmental pressures upon completion. FMD of the brachial artery and its sequelae are extremely rare, and therefore, there is no consensus on proper management.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased oxygen extraction as adaptation to acute renal ischemia.

Acute renal ischemia is an infrequently encountered clinical entity with occasionally devastating consequences. The renal compensation to acute ischemia is unknown and is the purpose of this report. Eight pigs were anesthetized and ventilated. Left atrial, aortic, CVP, left renal venous, and ureteral catheters were inserted. Renal blood flow (RBF) reduction was accomplished by the graded constriction of the left renal artery using a balloon occluder. Renal oxygen extraction ratio (RER, %), renal oxygen delivery (RO2D, cc/min per 100 gm), renal oxygen consumption (RVO2, cc/min/100 gm), creatinine clearance (CrCl, ml/min), and renal lactate production (delta [L], mg/min per hgm) were measured at baseline and following sequential 90-minute intervals of moderate and then severe left renal flow reduction. Significant increases in renal oxygen extraction were observed when RBF was severely limited (.30 +/- .05 vs .64 +/- .06, p < .01). CrCl decreased precipitously (16.5 +/- 4.6 vs 0.2 +/- 0.07, p < .05). Lactate production by the ischemic organs correlated with blood flow reduction (r = .546, p = .0034). In severe ischemia, healthy kidneys increase oxygen extraction to preserve oxygen consumption.

Hereditary protein S deficiency in a large New Jersey kindred.

PURPOSE: Protein S is a vitamin K-dependent anticoagulant protein that serves as a cofactor for activated protein C. Deficiency of protein S has been associated with recurrent thrombotic events. To characterize better the risks of thrombosis in protein S deficiency, we studied 62 members in a large kindred. METHOD: All members were evaluated by a thorough clinical history. Plasma samples were assayed for total protein S antigen and protein S activity. Upper and lower extremity venous duplex examinations were performed in the majority of adult members. RESULT: Twenty-six (40%) of the 62 family members were classified as deficient on the basis of either low total protein S antigen levels or low protein S functional activity. Five members deficient in protein S had 16 venous thrombotic events. In all members the onset of thrombotic events occurred after 19 years of age, with a tendency for recurrence. Three lower extremity deep venous thromboses that had been occult previously were first diagnosed on surveillance duplex scanning. Only one member whose protein S level was not deficient had a single episode of superficial thrombophlebitis. CONCLUSION: Our findings in this large kindred confirm an autosomal-dominant inheritance pattern. Thrombotic events occurred after the age of 19 years in affected individuals and tended to be recurrent. The diagnosis of protein S deficiency is based on functional and immunologic plasma assays. In this study venous duplex scanning proved to be a useful diagnostic adjuvant.

The comparative evaluation of three-dimensional magnetic resonance for carotid artery disease.

Conventional angiography is the current standard for the evaluation of carotid artery disease. The excellent resolution of this invasive study is offset by the potential for contrast-related, embolic, and puncture site complications. Three-dimensional magnetic resonance angiography may offer a noninvasive diagnostic alternative. We examined this possibility by performing both conventional angiography and three-dimensional magnetic resonance angiography in 13 patients. Cervical duplex scans were also obtained in these patients. Contiguous transverse cervical magnetic resonance images were acquired in a 1.5 tesla magnet, by use of a posterior neck coil and a gradient echo pulse sequence. These "raw" data were transferred to a real-time workstation where three-dimensional cervical arterial images were reformatted, magnified, and examined from multiple angles. Total study time from patient positioning to image generation was approximately 30 minutes. In all patients, on three-dimensional magnetic resonance angiography the common, external, and internal carotid arteries and distal vertebral arteries were easily discernable and correctly identified as patent, stenotic, or occluded. Three-dimensional magnetic resonance angiography was not accurate in detecting carotid ulcers. The degree of internal carotid artery stenosis measured from the three-dimensional magnetic resonance angiography studies correlated well with the internal carotid artery stenosis measured with conventional angiography (r = 0.866, r2 = 75.1%, p = less than or equal to 0.0001). This recent technologic advance represents significant progress toward achieving the goal of completely noninvasive vascular assessment in this patient population.

Can intraoperative prebypass arteriography substitute for the preoperative arteriogram?

Preoperative contrast arteriography is presently considered a requirement when planning infrainguinal arterial reconstructions in patients with limb-threatening ischemia. We reviewed the clinical data from 22 infrainguinal bypasses done in 20 patients to see if appropriate decisions concerning operability and the nature of the operation could be made from the physical examination and noninvasive data supplemented by a limited intraoperative on-table prebypass arteriogram. The presence of a normal femoral pulse with either a normal thigh pulse volume tracing or a normal high-thigh index assured adequate inflow to the groin level. The presence of an arterial Doppler signal at the ankle level, heard with a hand held Doppler, confirmed the presence of patent outflow vessels for the distal anastomosis. The exact site of the distal anastomosis could be determined with the on-table prebypass arteriogram. In patients with limb-threatening ischemia due to occlusive disease limited to the infrainguinal arterial tree, an appropriate operative bypass may be performed without the aid of the preoperative arteriogram.

One hundred percent oxygen reverses muscle hypoxia in a rat hindlimb model of acute arterial occlusion.

Significant morbidity results from extremity ischemia after acute arterial occlusion. Reestablishment of arterial flow is considered to be the ideal treatment, yet substantial tissue loss can occur before this is accomplished. Using a rat hindlimb model we investigated whether the administration of 100% oxygen would decrease tissue hypoxia from acute arterial occlusion. Adult male Sprague-Dawley rats were used, and Po2 recordings were taken from the gastrocnemius muscle by use of an oxygen electrode. Baseline muscle Po2 was recorded, and then the femoral artery was occluded. Repeat recordings were made after 20 minutes of ventilation with room air and after an additional 20 minutes of ventilation with 100% oxygen (N = 10). Control groups consisted of animals undergoing occlusion but continued on room air (N = 3) and animals undergoing sham occlusion but receiving the period of 100% oxygen ventilation (N = 3). Femoral artery occlusion produced a reduction in muscle Po2 from 28.0 +/- 1.4 to 6.1 +/- 2.0 (mean +/- SEM, p less than 0.001). Ventilation with 100% oxygen reversed the tissue hypoxia produced by occlusion (27.3 +/- 2.0, p less than 0.001). The administration of 100% oxygen without femoral artery occlusion resulted in a higher tissue Po2 than the occluded + oxygen group (94 +/- 12 vs 27.3 +/- 2.0, p less than 0.001). Mean arterial blood pressure increased in the experimental group concomitant with the administration of 100% oxygen, but there was no correlation between final blood pressure and final tissue oxygen tension.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging of acute occlusive intestinal ischemia.

The mortality of acute superior mesenteric artery occlusion and mesenteric infarction remains high, in part because of the failure to identify the patients with the disorder. A reliable noninvasive diagnostic study may facilitate earlier definitive diagnosis and therapy. Proton magnetic resonance imaging may offer a noninvasive diagnostic alternative. We examined this possibility by using an experimental rabbit model of acute superior mesenteric artery occlusion in this study. Animals were scanned 1 hour after the ischemic insult. Relative intestinal wall signal intensity was increased in experimental (ischemic) animals when compared to sham operated controls on T2-weighted (4.35 +/- 0.5 vs 2.57 +/- 0.31, p less than 0.02) and proton spin density-weighted images (2.1 +/- 0.2 vs 1.4 +/- 0.21, p less than 0.05). Significant increases in image intensity were found on T2-weighted and proton spin density images when compared to control animals. Differences between groups could be further highlighted after the administration of a paramagnetic contrast agent gadolinium diethyltriamine pentacetic acid on T1-weighted images. The data from this preliminary study demonstrate that proton magnetic resonance imaging may be used to discriminate between ischemic and nonischemic small intestine. This noninvasive tool may someday become clinically useful to enhance our diagnostic capabilities when a diagnosis of acute superior mesenteric artery occlusion is being entertained.

Limits of cardiac compensation in anemic baboons.

The risk of homologous blood may cause physicians to withhold red cell treatment after acute blood loss. We believe that in the euvolemic patient with acute anemia, the heart is the principal organ at risk. The cardiac compensation to extreme anemia is unknown and is the purpose of this report. Fourteen adult baboons were anesthetized, paralyzed, and ventilated with room air. Left atrial and coronary sinus catheters were inserted surgically. Experimental animals (n = 7) were hemodiluted at constant left atrial pressure with 5% human serum albumin. Control animals (n = 7) underwent similar volume exchanges with fresh, cross-matched, homologous red blood cells resuspended in human serum albumin, also at constant left atrial pressure. Six of seven experimental animals survived until hematocrit levels were 4%. Adequate cardiac compensation was observed until hematocrit levels were less than 10%. Increased flow, without increases in the O2 extraction ratio, was the mechanism of compensation used by the healthy heart with patent coronary vessels.

Survival after a second episode of toxic epidermal necrolysis.

Toxic epidermal necrolysis resulting from severe hypersensitivity to medication has a reported mortality of up to 66%. A patient surviving two episodes with more than a 50% skin loss is unprecedented in the medical literature. Mortality has been associated with many factors, including delayed reepithelialization, persistent skin slough, coagulopathy, severe hypoproteinemia, and sepsis. It may be possible to decrease morbidity and mortality by preventing the shearing of epidermis, thereby limiting the denuded areas. This case report describes the successful management of our patient's second episode of toxic epidermal necrolysis. The treatment of this patient in our specialized burn center consisted of careful fluid and electrolyte management, nutritional support, standard topical antimicrobials, and new modalities of local wound management.

Oxygen extraction ratio: a valid indicator of myocardial metabolism in anemia.

We have shown that primates adequately compensate for acute normovolemic anemia to hematocrits (HCT) of 10%. We have described a whole-body extraction ratio (O2 consumption/O2 delivery; ER) of 50% as a reliable physiologic indicator of transfusion need. There is concern that whole-body ER may not accurately reflect impaired myocardial metabolism. The onset of significant lactate production by the left ventricle is an indicator of anaerobic metabolism. Our purpose is to compare left ventricular lactate metabolism (arterial-coronary sinus lactate; delta [L]) to ER in acute normovolemic anemia. Fourteen adult baboons were anesthetized, paralyzed, and ventilated on room air. Left atrial, coronary sinus, aortic, and Swan-Ganz catheters were inserted. Experimental animals (N = 7) were hemodiluted, at constant left atrial pressure (LAP), with 5% human serum albumin (HSA) to a HCT below 4%. Control animals (N = 7) underwent similar volume exchanges, also at constant LAP, with homologous RBCs resuspended in HSA. Whole-body extraction ratio and left ventricular lactate production were measured at baseline and at hematocrits of 20, 10, 6, and 4% in the experimental group. Data were obtained at similar volume exchange points in the control group. Significant lactate production occurred only in the experimental animals (P less than 0.05) when extraction ratio exceeded 50%. Significant lactate production does not occur before the whole-body ER exceeds 50%. ER appears to be a valid indicator of myocardial metabolism in anemia, in this setting.