Traumatic injuries to the pregnant patient: a critical literature review.

INTRODUCTION: Trauma during pregnancy is the leading non-obstetrical cause of maternal death and a significant public health burden. This study reviews the most common causes of trauma during pregnancy, morbidity, and mortality, and the impact upon perinatal outcomes associated with trauma, providing a management approach to pregnant trauma patients. MATERIALS AND METHODS: A systematic review of the current literature from January 2006 to July 2016 was performed. RESULTS: Fifty-one articles were identified, including a total of 95,949 patients. Motor vehicle crash was the most frequent cause of blunt trauma, followed by falls, assault both domestic and interpersonal violence, and penetrating injuries (gunshot and stab wounds). CONCLUSIONS: Trauma in pregnant women is associated with high rates of adverse maternal and neonatal outcomes. Knowledge of the mechanism of injury is important to identify the potential injuries and the complexity of the management of these patients. As in all traumatic events, prevention is of paramount importance.

The impact of measurement of respiratory quotient by indirect calorimetry on the achievement of nitrogen balance in patients with severe traumatic brain injury.

BACKGROUND: This study evaluated the impact of IC on the optimization of nutritional support and the achievement of +NB in patients with TBI. MATERIALS AND METHODS: 27 patients (GCS ≤ 8), treated with a 5-day multimodality monitoring and goal-directed therapy protocol, received enteral nutrition on day 1 followed by IC on days 3 and 5 and assessment of NB on day 7. In the first cohort (n = 11), no adjustment in kcal was made. In the second cohort (n = 16), nutrition was targeted to an RQ of 0.83 by day 3. The first cohort was analyzed with respect to NB status; the second cohort was compared to patients with (-) and +NB of the first cohort. Data (mean ± SD) were analyzed with unpaired t test, and Chi square and Fisher exact tests. RESULTS: 4/11(36 %) patients in the first cohort had +NB. The predicted mortality by TRISS, substrate utilization, and RQ was significantly lower compared to the second cohort. The mortality predicted by the CrasH model did not differ between the two cohorts. A RQ of 0.74 was associated with the preferential use of fat and protein and -NB, whereas a RQ of 0.84 favored utilization of carbohydrates and +NB. All patients whose kcal intake was adjusted based on the RQ on day 3 reached a +NB by day 7. CONCLUSION: An increase in kcal ≥25 % in patients with a RQ < 0.83 on day 3 improves substrate utilization, decreases protein utilization and optimizes the achievement of +NB by day 7.

Isolated transverse process fractures: insignificant injury or marker of complex injury pattern?

INTRODUCTION: This study investigates the incidence of isolated transverse process fractures (ITPFx) amongst vertebral fractures in trauma patients, and specific-associated injury patterns present in patients with ITPFx. MATERIALS AND METHODS: A retrospective, 4-year review of our Level 1 Trauma Center registry was performed. Patients with blunt spinal column fractures were identified. Data collected included patient demographics, Injury Severity Score (ISS), type of imaging obtained, and concomitant injuries, including rib and pelvic fractures, liver, spleen, and kidney injury (SOI). RESULTS: Of the 10,186 patients admitted during the study period, 881 (8.6%) suffered blunt thoraco-abdominal trauma resulting in vertebral fractures; 214/881 (24%) had ITPFx. All patients (10,186) underwent dedicated spinal multi-detector CT (MDCT) imaging; 26/214 (12.1%) patients had MRI. In all 26 patients, the MRI confirmed the CT findings. 202/214 (94.4%) had associated injuries: rib and pelvic fractures, 45.5 and 20.2%, respectively, and splenic, liver and kidney injury with an incidence of 13.8, 10.9, and 9.4%, respectively. A higher incidence of rib fractures was associated with ITPFx at the T1-4 levels, whereas ITPFx at the level of L5 were associated with pelvic fractures and SOI. Multiple logistic regression analysis identified T1-4 and L5 fractures as predictors of rib fractures and pelvic fractures independent of ISS, with OR: 2.55 (95% CI: 1.12-5.82) and 6.81 (95% CI: 3.14-14.78), respectively. CONCLUSIONS: Based on the results of this study, we conclude that: (1) the use of MDCT imaging has increased the rate of identification of ITPFx; (2) dedicated spinal MDCT reconstruction and MRI may not be necessary to diagnose isolated thoracic and lumbar ITPFx; and (3) ITPFx of the thoracic spine and lower lumbar spine are markers of associated rib fractures and pelvic ring fractures, respectively, as well as of solid organ injuries.

Contemporary wars and their contributions to vascular injury management.

INTRODUCTION: Man's inhumanity for man still knows no boundaries, as we continue as a species as a whole to engage in war. According to Kohn's Dictionary of Wars [1], of over 3,700 years of recorded history, there have been a total of 3,010 wars. One is hard pressed to actually find a period of time in which here has not been an active conflict in the globe. The world has experienced two world wars: WWI (1914-1918) and WWII (1939-1945). The total number of military casualties in WWI was over 37 million, while WWII so far, has been the deadliest military conflict in history with over 60 million people killed accounting for slightly over 2.5% of the world's population. MATERIAL AND METHODS: The purpose of this study is to review contemporary wars and their contributions to vascular injury management. It is precisely wartime contributions that have led to the more precise identification and management of these injuries resulting in countless lives and extremities saved. However, surgeons dealing with vascular injuries have faced a tough and arduous road. Their journey was initiated by surgical mavericks which undaunted, pressed on against all odds guided by William Stewart Halsted's classic statement in 1912: "One of the chief fascinations in surgery is the management of wounded vessels." CONCLUSION: Contemporary wars of the XX-XXI centuries gave birth, defined and advanced the field of vascular injury management.

Diagnosis of acute cholecystitis: sensitivity of sonography, cholescintigraphy, and combined sonography-cholescintigraphy.

BACKGROUND: Radiographic diagnosis of acute cholecystitis can be established using ultrasonography (US), cholecystoscintigraphy (HIDA), or both. Although both modalities have been effective in diagnosing acute cholecystitis (AC), physicians from the emergency department and admitting surgeons continue to request both tests in an attempt to increase the diagnostic accuracy of AC. This article reports the institutional experience of a large tertiary care health care facility, with respect to the sensitivity of US, HIDA, and combined US and HIDA. STUDY DESIGN: We conducted a retrospective review of 132 patients diagnosed with AC who underwent laparoscopic cholecystectomy during the same hospitalization. Patients were stratified into three groups: Group 1 (Gp1, n = 50) included patients who underwent US alone, group 2 (Gp2, n = 28) included patients who underwent HIDA scan alone, and group 3 (Gp3, n = 54) included patients who underwent both US and HIDA. RESULTS: The three groups did not differ with respect to age, liver chemistry, time to operation, and hospital length of stay. The sensitivity of US, HIDA, and combined US/HIDA as diagnostic modalities for acute cholecystitis was referenced to histopathologic confirmation. Sensitivity was 24 of 50 (48%), 24 of 28 (86%), and 49 of 54 (90%) for US, HIDA, and the combination of US/HIDA, respectively. CONCLUSIONS: HIDA scan is a more sensitive test than US in diagnosing patients with AC. Based on the results of this study, we recommend that HIDA scan should be used as the first diagnostic modality in patients with suspected acute cholecystitis; US should be used to confirm the presence of gallbladder stones rather than to diagnose AC.

Prolonged lactate clearance is associated with increased mortality in the surgical intensive care unit.

BACKGROUND: Failure of arterial serum lactate to achieve normal levels has been associated with an increased mortality among medical and trauma patients. At our institution the ability of the patient to normalize arterial serum lactate has been utilized as an end point of resuscitation. In this study, we examine the correlation between length of time to lactate normalization and mortality. METHODS: The charts of 95 consecutive surgical intensive care unit (SICU) patients requiring hemodynamic monitoring or therapy were reviewed retrospectively. Hemodynamic, demographic, and laboratory data were recorded. Patients were stratified by lactate normalization time, and a subgroup analysis of survivors and nonsurvivors was performed by univariate and multivariate analysis. RESULTS: Patients not achieving a normal lactate level sustained a 100% hospital mortality rate. Those clearing between 48 and 96 hours sustained a 42.5% mortality rate. Patients normalizing in 24 to 48 hours had a 13.3% mortality rate, and those clearing in less than 24 hours had a mortality rate of 3.9%. Subgroup analysis by survival revealed differences in time to lactate clearance, initial blood pressure, and initial lactate on univariate analysis. On multivariate analysis only time of lactate clearance was found to differ. CONCLUSIONS: Prolongation of lactate clearance is associated with increasing mortality. Failure of a patient to normalize lactate is associated with 100% mortality. Measurement of arterial serum lactate is a simple and effective predictor of outcome and end point of therapy.

Effect of hematocrit on regional oxygen delivery and extraction in an adult respiratory distress syndrome animal model.

BACKGROUND: The purpose of this prospective, randomized, controlled study was to investigate the effects of hematocrit (Hct) on regional oxygen delivery and extraction following induction of adult respiratory distress syndrome (ARDS) in an animal model. METHODS: Animals were instrumented to monitor central venous pressure (CVP), systemic mean arterial pressure (MAP), pulmonary artery occlusion pressure (PAOP), and cardiac output (CO) and to measure blood flow in the renal, hepatic, and superior mesenteric arteries and portal vein. ARDS was induced, positive end expiratory pressure (PEEP) applied and CO was maximized with volume loading and epinephrine infusion. Data were acquired at baseline (BL) and at Hct levels ranging from 25% to 50%. RESULTS: Systemic DO(2) increased steadily and significantly with increased Hct. Systemic O(2) extraction ratio (O(2)ER) decreased significantly with increasing Hct until a threshold value of 40%, after which further increases in Hct did not cause a statistically significant decrease in O(2)ER. Similarly, renal and hepatic DO(2) increased and O(2)ER decreased in a statistical significant manner with transfusions up to a Hct of 35%. In the splanchnic circulation blood transfusions did not cause any statistically significant increase in DO(2), and O(2)ER showed no decrease after an Hct of 35%. Systemic, renal, hepatic, and splanchnic VO(2) were not affected by changes in Hct. Blood viscosity decreased from a baseline value of 2.9+/-0.2 centipoise at a Hct of 38% to 2.3+/-0.1 centipoise at a Hct of 25% (P<0.05). Viscosity increased progressively with increasing hematocrits and reached the value of 4.2+/-0.2 centipoise at an Hct of 50% (P<0.05 versus Hct 30%, 35%, 40%, 45%). CONCLUSIONS: Based on the results of this non-supply-dependent animal model we conclude that a progressive increase in Hct up to 40% causes a corresponding increase in systemic DO(2) associated with a decrease in O(2)ER. However, there is no improvement in renal, hepatic, and splanchnic DO(2) and O(2)ER after a threshold Hct of 35%. All other factors being the same, an Hct greater than 35% may in fact cause a decrease in blood flow rate and change in blood flow characteristics as a consequence of increased blood kinematic viscosity, which may alter and compromise cellular oxygen transfer.

Warfarin anticoagulation in the perioperative period: is it safe?

This study was undertaken to determine if warfarin anticoagulation could be safely continued during surgery and in the perioperative period. An animal model was followed by a prospective human study of all patients on heparin or warfarin at the time of surgery. Twenty-four rabbits underwent laparotomy, during which a controlled liver injury was created and repaired. Group 1 (Warf) was anticoagulated with warfarin to raise the mean international normalization ratio (INR) to 2.5-3.0. Group 2 (Hep) was anticoagulated with heparin to raise the activated partial thromboplastin time to 1.5-2.0 times control. The heparin was then stopped 6 hr prior to surgery and resumed 6 hr postoperatively without a bolus. Group 3 (control) was not anticoagulated and received saline infusion. For the human study, data were collected on 40 patients undergoing 50 operations from October 1996 to January 1998. The results of this study reveal that (1) bleeding was less in the group anticoagulated with warfarin throughout surgery in the animal model, (2) bleeding complications were less in the patients continued on warfarin through surgery than those on heparin (3) older patients may have an increased risk of bleeding, and (4) an INR of >3 at the time of surgery may increase the risk of bleeding.

Control of proximal hypertension during aortic cross-clamping: its effect on cerebrospinal fluid dynamics and spinal cord perfusion pressure.

Postoperative paraplegia remains the most devastating complication of surgery of the descending and thoraco-abdominal aorta. Control of the proximal hypertension that follows cross-clamping of the thoracic aorta to repain aneurysms of the descending and thoraco-abdominal aorta is necessary to prevent left ventricular failure, myocardial infarction, and hemorrhagic cerebral events. Both pharmacological and mechanical modalities used to control central hypertension during aortic occlusion affect cerebrospinal fluid dynamics and spinal cord perfusion pressure. Sodium nitroprusside (doses >5 microg/kg/min), the most widely used pharmacological agent, decreases spinal cord perfusion pressure because it increases cerebrospinal fluid pressure and decreases blood pressure distal to the aortic cross-clamp. This effect cannot be prevented by drainage of cerebrospinal fluid. Nitroglycerin also decreases spinal cord perfusion pressure, but its effects on cerebrospinal fluid dynamics can be countered by drainage of cerebrospinal fluid. Active distal perfusion with left atrial-femoral artery bypass can provide adequate perfusion of the circulation distal to the aortic cross-clamp while simultaneously reducing cerebrospinal fluid pressure. This approach can maintain mesenteric and spinal cord blood flow, therefore preventing the multiple organ dysfunction syndrome caused by release of cytokines from the splanchnic district and decreasing the incidence of postoperative paraplegia from spinal cord ischemia. In cases of limited retroperfusion, partial exsanguination and cerebrospinal fluid drainage can be used in conjunction with left atrial-femoral artery bypass to prevent rises in cerebrospinal fluid pressure and maintain spinal cord blood flow above the threshold necessary to prevent neurological injury. The use of oxygenated perfluorocarbons in the subarachnoid space to provide passive oxygenation of the spinal cord during aortic occlusion remains experimental and requires further investigation.

Effect of nitroglycerin and cerebrospinal fluid drainage on spinal cord perfusion pressure and paraplegia during aortic cross-clamping.

When sodium nitroprusside (SNP) is used to control proximal blood pressure (Px-BP) during cross-clamping (AXC) of the thoracic aorta, it decreases spinal cord perfusion pressure (SCPP) by reducing distal aortic pressure (Ds-BP) and increasing cerebrospinal fluid pressure (CSFP). The decrease cannot be reversed by CSF drainage (CSFD) because such drainage is limited by a reduction in compliance of the spinal canal. Nitroglycerin can also be used to control Px-BP, but its effect on CSF dynamics has not previously been investigated. In the present study we have compared the effects of NTG alone and in combination with CSFD, with SNP and CSFD. Each group (Gp) of six dogs was treated with SNP + CSFD (Gp 1), NTG alone (Gp 2), and NTG + CSFD (Gp 3). Left carotid and right femoral arteries were catheterized to monitor Px-BP and Ds-BP, respectively. CSFP was monitored and CSF was drained through a spinal needle placed in the cisterna cerebellomedullaris. The thoracic aorta was cross-clamped via a left thoracotomy for 60 min. Data were acquired at baseline, during aortic occlusion, and 24 hr after surgery. There were no significant differences in any measurements among the three groups before AXC; after AXC, Px-BP was maintained between 85 and 95 mm Hg in all groups. Ds-BP was significantly lower in Gp 1 than Gp 2 and 3 (7 +/- 2 mm Hg vs. 13 +/- 3 mm Hg and 17 +/- 2 mm Hg, respectively P < 0.05). CSFP did not differ between Gp 1 and 2 (10 +/- 3 mm Hg vs. 9 +/- 1 mm Hg, P > 0.05). CSFD effectively kept CSFP at zero values in Gp 3 during AXC, but not in Gp 1. SCPP was significantly higher in Gp 3 than in Gp 1 and 2 (17 +/- 2 mm Hg vs -3 +/- 4 mm Hg and 4 +/- 1 mm Hg, respectively, P < 0.05). All animals in Gp 1 and 2 suffered paraplegia, as opposed to none in Gp 3. NTG causes paraplegia by decreasing SCPP. When used in conjunction with CSFD, it controls Px-BP without causing paraplegia. CSFD cannot counteract the negative effects of SNP on SCPP; therefore, SNP contributes to postoperative paraplegia. The effects of NTG on cerebrospinal fluid dynamics are different from those of SNP. We caution surgeons against the use of NTG without CSFD during aortic cross-clamping.

Comparative study of biological glues: cryoprecipitate glue, two-component fibrin sealant, and "French" glue.

BACKGROUND: Although biological glues have been used clinically in cardiovascular operations, there are no comprehensive comparative studies to help clinicians select one glue over another. In this study we determined the efficacy in controlling suture line and surface bleeding and the biophysical properties of cryoprecipitate glue, two-component fibrin sealant, and "French" glue containing gelatin-resorcinol-formaldehyde-glutaraldehyde (GRFG). METHODS: Twenty-four dogs underwent a standardized atriotomy and aortotomy; the incisions were closed with interrupted 3-0 polypropylene sutures placed 3 mm apart. All dogs had a 3- by 3-cm area of the anterior wall of the right ventricle abraded until bleeding occurred. The animals were randomly allocated into four groups: in group 1 (n = 6) bleeding from the suture lines and from the epicardium was treated with cryoprecipitate glue; in group 2 (n = 6) bleeding was treated with two-component fibrin sealant; group 3 (n = 6) was treated with GRFG glue; group 4 (n = 6) was the untreated control group. The glues were also evaluated with regard to histomorphology, tensile strength, and virology. RESULTS: The cryoprecipitate glue and the two-component fibrin sealant glue were equally effective in controlling bleeding from the aortic and atrial suture lines. Although the GRFG glue slowed bleeding significantly at both sites compared to baseline, it did not provide total control. The control group required additional sutures to control bleeding. The cryoprecipitate glue and the two-component fibrin sealant provided a satisfactory clot in 3 to 4 seconds on the epicardium, whereas the GRFG glue generated a poor clot. There were minimal adhesions in the subpericardial space in the cryoprecipitate and the two-component fibrin sealant groups, whereas moderate-to-dense adhesions were present in the GRFG glue group at 6 weeks. The two-component fibrin sealant was completely reabsorbed by 10 days, but cryoprecipitate and GRFG glues were still present. On histologic examination, both fibrin glues exhibited minimal tissue reaction; in contrast, extensive fibroblastic proliferation was caused by the GRFG glue. The two-component and GRFG glues had outstanding adhesive property; in contrast, the cryoprecipitate glue did not show any adhesive power. The GRFG glue had a significantly greater tensile strength than the two-component fibrin sealant. Random samples from both cryoprecipitate and the two-component fibrin glue were free of hepatitis and retrovirus. CONCLUSIONS: The GRFG glue should be used as a tissue reinforcer; the two-component fibrin sealer is preferable when hemostatic action must be accompanied with mechanical barrier; and finally, the cryoprecipitate glue can be used when hemostatic action is the only requirement.

Local anesthesia is superior to spinal anesthesia for anorectal surgical procedures.

In this prospective study we compared local with spinal anesthesia for anorectal surgical procedures with regard to pain control, recovery time before unassisted ambulation, incidence of postoperative complications, length of hospital stay, and cost effectiveness in 80 consecutive patients. Patients were allocated in two groups: group 1 (n = 52) received local anesthesia, and group 2 (n = 28) had spinal anesthesia. There were no intraoperative complications related to the anesthetic technique, and there was no difference between groups in the number of doses of narcotics required to control postoperative pain (1.2 +/- 1.5 vs 1.8 +/- 1.7 in group 1 and 2 respectively, P > 0.05). Recovery time before unassisted ambulation was significantly longer in group 2 (139 +/- 96 minutes in group 2 vs 82 +/- 62 minutes in group 1, P < 0.05). There were 21/52 complications in group 1 in contrast to 21/28 in group 2, (P < 0.05). There was no difference between groups in the postoperative incidence of nausea, vomiting, headache, weakness, and constipation; however, the incidence of postoperative urinary retention was significantly higher in group 2 (5/52 in group 1 vs 9/28 in group 2, P < 0.05). As a result of urinary retention, more patients in group 2 required overnight hospitalization (12/52 in group 1 vs 21/28 in group 2, P < 0.05). Patients in group 2 required 36 hospital days in contrast to 21 days for patients in group 1, P < 0.05. The difference in hospital days resulted in $18,000 greater cost for patients in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical patients with pseudomembranous colitis: factors affecting prognosis.

BACKGROUND: Although several studies have identified the factors that contribute to the development of antibiotic-associated colitis (AAC), little data are available in regard to those factors that may affect the prognosis of patients with the disease. Therefore we conducted a retrospective analysis of 201 surgical patients with AAC to identify risk factors predictive of increased morbidity or mortality. METHODS: We conducted a review of the charts of 201 surgical patients hospitalized between Jan. 1, 1991, and June 30, 1993, in whom AAC developed. AAC was defined as the presence of diarrhea associated with a positive latex agglutination or toxin assay for Clostridium difficile. An additional 52 procedure-matched charts of patients admitted to a surgical service during the same period were also reviewed and constituted the control group. We analyzed the contribution of 21 variables to prognosis in both groups. RESULTS: There was no difference between the two groups in the preoperative length of stay, the number of antibiotics per patient and the number of antibiotic-days, number of patients receiving preoperative bowel preparation, total parenteral nutrition, and overall mortality rate. Patients in the control group were at increased risk of death if they had a history of preexisting renal dysfunction, prolonged preoperative hospital stay, and a poor nutritional status. AAC developed 10.0 +/- 13.8 days after operation in the study group. All patients were receiving multiple antibiotics at the time of diagnosis (3.6 +/- 7.5 antibiotic), with a mean of 14.3 +/- 20.7 antibiotic-days. The overall mortality rate in the study group was 8%. In five patients (2%) toxic megacolon developed; four deaths occurred among these patients (80% mortality rate). A 25% mortality rate was directly attributable to complications of AAC. Six variables were identified as predictive of increased mortality rate: steroids, laxatives, length of preoperative stay, postoperative interval before the onset of symptoms, use of total parenteral nutrition, and abdominal distention. CONCLUSIONS: AAC carries a significant mortality rate in surgical patients; therefore the diagnosis of AAC should be aggressively pursued and patients with the disease should be promptly treated. Patients receiving steroids, total parenteral nutrition, and multiple antibiotics in whom signs and symptoms of AAC develop late in their postoperative course, and patients with abdominal distention and marked leukocytosis, are at increased risk of dying of AAC and should be aggressively treated.

Do surgical residents, emergency medicine physicians, and nurses experience significant radiation exposure during the resuscitation of trauma patients?

During this study we investigated the yearly risk of radiation exposure for surgical residents (group 1, n = 8), emergency department (ED) physicians (group 2, n = 6) and nurses (group 3, n = 97) participating in the resuscitation of trauma victims in the emergency department of a 500-bed teaching hospital. Dosimeter readings of the three study groups were recorded monthly over the 1-year study period. During the study interval, 758 patients underwent resuscitation following trauma; 2098 portable radiographs (758 chest films, 758 lateral cervical spine films, and 582 radiographs of the pelvis) were obtained during the resuscitation phase of these patients. The total radiation exposure for group 3 was significantly greater than that for groups 1 and 2 (340 +/- 50 vs. 160 +/- 112 and 20 +/- 14 mrem, respectively, p < 0.01). Individual residents received a significantly greater amount of radiation than ED physicians and nurses (20 +/- 28 vs. 3.3 +/- 2.0 and 3.5 +/- 2.0 mrem, respectively, p < 0.05). However, despite repeated exposure to radiation, individuals in the three groups did not exceed the safety limits of 0.05 Gy/year set by the National Council on Radiation Protection and Measurements. Based on the results of this study, we conclude that trauma resuscitation teams can provide quality care to their patients without concern over the detrimental effects of radiation exposure, provided that the basic principles of radiation protection are followed.

Dynamic cardiomyoplasty: left ventricular diastolic compliance at different skeletal muscle tensions.

The possible limitation of left ventricular (LV) relaxation during diastole is a concern for clinicians and researchers utilizing dynamic cardiomyoplasty. This study was designed to evaluate the LV compliance at three different skeletal muscle tensions, in a normal heart and in a failing heart, created by propranolol infusion (11.6 mg/kg). A biventricular latissimus dorsi muscle (LDM) wrap was performed in 10 dogs. The LV pressure (Millar) and two minor axis dimensions (endocardial crystals) were measured. LV pressure-volume loops were constructed, and LV diastolic compliance was calculated. The measurements were obtained before wrap and after wrap at different LDM tensions with 0, 5, and 10 volts stimulation each time. These measurements were repeated after propranolol treatment. The results showed that LV diastolic compliance (dV/dP) was 1.79 before wrap and about 0.7 after wrap, and after propranolol, at various tensions and stimulations. LDM wrap decreased LV compliance significantly. LV compliance was not significantly affected by changing tension or voltage of stimulation in either the failing or the non-failing heart. The reduction in compliance may be an indication that LDM wrap causes a limitation of LV relaxation, which is one of wrap's deleterious effects.

The relationship between timing of repair of disruptions and subsequent aneurysm formation in laser-assisted microvascular anastomoses.

In this study we investigated the effects of duration of bleeding after laser-assisted microvascular anastomoses and the amount of laser energy used to control bleeding on aneurysm formation. Eighty femoral arteries were exposed in 40 Sprague-Dawley rats anesthetized with chloral hydrate. The arteries were transected and then anastomosed end-to-end with three nylon stay sutures followed by irradiation of the vessels with energy from a CO2 laser. The laser power was kept at 90 mW, and each of three segments between stay sutures was exposed for 6 seconds to continuous laser energy. If anastomotic disruption (defined as bleeding after completion of the anastomosis) occurred, it was controlled with pressure over the disrupted site for 10, 25, or 40 seconds. Disruptions were required with exposure to additional laser energy for either 6 (group 1) or 12 seconds (group 2). The anastomoses were inspected at 21 days postoperatively to assess patency and aneurysm formation. Twenty-six of 80 vessels (32%) were anastomosed without the occurrence of disruptions: these 26 vessels had a 100 per cent patency rate and did not develop aneurysms. In group 1, the incidence of redisruption following a primary disruption was the same irrespective of duration of bleeding (4/8, 3/6, and 3/6 for 10-, 25-, and 40-seconds bleeding time, respectively P = NS). Similarly, there was no difference in the incidence of aneurysm formation in this group (0/8, 2/6, and 2/6 for 10, 25, and 40", respectively, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of seroma formation after dissection of musculocutaneous flaps.

Dissection of musculocutaneous flaps is uniformly followed by the formation of seroma if drains are not used. Drains can be colonized and form deep tissue infection if left in place for a long time. In this study we investigated whether talc poudrage could prevent the formation of seroma following dissection of the latissimus dorsi muscle in a canine model. Twelve mongrel dogs were randomized into two groups. Group 1 (n = 6) underwent dissection of the left latissimus dorsi muscle which was rotated as a pedicle flap into the left chest through a second intercostal space thoracotomy. The wound was closed in layers without drains. Group 2 (n = 6) had the same procedure, but before closure of the wound, USP talc was applied to the tissues. All animals received cefazolin (500 mg) Q8h for 48 hours perioperatively. Animals were followed for 1-5 months. Wounds with fluctuation were aspirated as many times as necessary and the amount of fluid was recorded. All Group 1 animals developed seromas, in contrast, only one animal in group 2 had a seroma. There was a significant difference in the amount of fluid aspirated for each animal between the two groups (280 +/- 80 in group 1 vs 25 +/- 25 ml in group 2, P < 0.05). The total amount of fluid drained in group 1 was 1730 ml, whereas only 150 ml was aspirated in group 2. Group 1 animals required a total of 11 aspirations to control seromas, in contrast, only one aspiration was needed in group 2. No abscess was identified at postmortem in either group. Based on the results of this study we conclude that talc poudrage can be safely used to minimize seroma formation after dissection of musculocutaneous flaps.

Issues surrounding spinal cord protection.

In summary, paraplegia following procedures on the thoracic and thoraco-abdominal aorta is an unpredictable and dreadful complication of multifactorial origin. However, it appears that the major causes of immediate post-operative paraplegia are the depth and duration of ischemia during the period of aortic cross-clamping and failure to identify and reimplant critical vessels that supply blood to the spinal cord. Delayed paraplegia, which has been reported to occur from 1 to 21 days after surgery, is most commonly caused by postoperative hypotension. We believe that the final approach to the prevention of paraplegia following procedures on the thoracic aorta will be one that involves the use of a technique to assure oxygenation of the spinal cord during aortic cross-clamping, through an alternate vascular tree, along with a method that can uniformly depict critical vessels that must be reimplanted at the time of surgery.

Intrathecal perfusion of an oxygenated perfluorocarbon prevents paraplegia after aortic occlusion.

A canine model was used to evaluate the effects of continuous intrathecal perfusion of an oxygenated perfluorocarbon emulsion on systemic and cerebral hemodynamics and neurologic outcome after 70 minutes of normothermic aortic occlusion. Twelve mongrel dogs were instrumented to monitor proximal and distal arterial blood pressure, cerebrospinal fluid pressure, spinal cord perfusion pressure, and somatosensory evoked potentials. The intrathecal perfusion apparatus consisted of two perfusing catheters, placed in the intrathecal space through a laminectomy, and a draining catheter percutaneously inserted in the cisterna cerebellomedullaris. The aorta was cross-clamped just distal to the left subclavian artery for 70 minutes. Animals were randomized into two groups: group 1 (n = 6) animals were treated with intrathecal perfusion of saline solution, whereas group 2 (n = 6) animals received oxygenated Fluosol-DA 20%. Data were acquired at baseline, during the cross-clamp period, and after reperfusion. Normothermic Fluosol or saline solution was infused at a rate of 15 mL/min beginning 15 minutes before cross-clamping and continued throughout the ischemic interval. There was no difference in proximal arterial blood pressure (97.2 versus 95.4 mm Hg; p > 0.05) or distal arterial blood pressure (14.6 versus 15.0; p > 0.05) between the two groups throughout the cross-clamp interval. Cerebrospinal fluid pressure rose significantly in both groups with the onset of intrathecal perfusion of either saline solution or Fluosol (7 +/- 1 versus 24 +/- 5 and 8 +/- 1 versus 40 +/- 4 mm Hg, respectively; p < 0.05). The rise in cerebrospinal fluid pressure was sustained throughout the perfusion interval in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)