A five-year U.S. Army experience with 36,250 abdominal hernia repairs.

Thirty-six thousand two hundred fifty abdominal hernia repairs were performed in U.S. Army medical treatment facilities during a five-year period. This study presents data about the type of hernia, incidence of complications by obstruction or strangulation, age, sex, and mortality. Hernias occurring with intestinal obstruction or gangrene (strangulation) are referred to as complicated hernias. Inguinal hernias in children less than two years of age, femoral hernias, and unusual (such as internal or obturator) hernias were found to have an increased incidence of complications. Surgical repair of ventral, umbilical, and femoral hernias was done with a low surgical risk and the presence of complications did not significantly increase this risk. An increased risk of mortality is associated with the repair of complicated unusual hernias and complicated inguinal hernias in patients more than 60 years of age.

Basic and advanced combat casualty care: a military problem.

Advanced Trauma Life Support (ATLS) takes a standardized approach to casualty management. It is most appropriate for civilian trauma and medical providers who do not manage trauma patients on a regular basis. Data presented herein show that a different type of patient is seen in wartime, and that much additional teaching and information dispersal will be needed to prepare medical personnel for wartime.

Pericardial substitutes: a survey.

Many thoracic surgeons have used pericardial substitutes to reduce the risk of reoperation, but there have been few reports of these procedures. Therefore, we used a questionnaire to gather information on experience with use of pericardial substitutes and to document the findings at reoperation. A six-question survey was sent to 2,344 members of The Society of Thoracic Surgeons, requesting surgeons to list their experience with pericardial substitutes and at reoperation in patients with these substitutes in place. Of the 634 surgeons who responded to the survey, 120 reported the insertion of 3,828 pericardial substitutes. Two hundred thirty-six reoperations were reported by 89 surgeons. None of the pericardial substitutes was reported to be completely successful in facilitating reoperation. The experience with polytetrafluoroethylene (PTFE) pericardial substitutes was reported to be significantly more satisfactory than that with all other substitutes (p = 0.0004 by chi-square analysis), but 14% of surgeons who used PTFE said they were dissatisfied at reoperation. Based on the results of this survey, we suggest caution, careful documentation, and long-term follow-up studies before widespread use of pericardial substitutes can be recommended.

A new look at pericardial substitutes.

The presence of pericardial adhesions may increase morbidity and mortality during reoperation for cardiac disease. Pericardial substitutes (patches) are commercially available, and reportedly they reduce or prevent adhesions. We implanted five (1984 to 1985) newer pericardial substitutes in dogs. A new polytetrafluoroethylene surgical membrane, two types of glutaraldehyde-stabilized bovine pericardium, formaldehyde-preserved bovine pericardium, and glutaraldehyde-stabilized equine pericardial patches were each implanted in six adult dogs (total 30 dogs) with two dogs from each of the five groups killed at 3, 9, and 18 months. At autopsy the condition of each patch was recorded photographically, and specimens were substituted for histologic examination. Adhesions and epicardial reactions were graded as none, minimal, moderate, or severe. None of the materials produced severe pericardial adhesions, and no adhesions were detected in nine dogs. Eleven dogs had no epicardial reaction and only one showed a severe reaction. Adhesions to portions of the suture line required sharp dissection in 11 dogs. If there is concern over the possibility of calcification in heterologous tissue, polytetrafluoroethylene may be chosen. Patch type did not significantly alter patch behavior.

Quantitative evaluation of the myocardial preservative characteristics of nifedipine during hypothermic myocardial ischemia.

Nifedipine, a slow calcium-channel blocker, has been used to preserve myocardial function in the ischemic heart. To quantitatively evaluate the effectiveness of nifedipine as a cardioplegic agent during moderate hypothermia (28 degrees C), 15 pigs were evaluated on total and right heart bypass with measurement at normothermia and after 1 hour of hypothermic ischemia of stroke volume, coronary blood flow, myocardial oxygen consumption, and lactate extraction. Myocardial tissue gases (oxygen and carbon dioxide) were continuously monitored. Animals were divided into three groups: hypothermic ischemia, hypothermic ischemia with infusion of nifedipine carrier without nifedipine, and hypothermic ischemia with nifedipine and its carrier. A significant decrease in stroke volume was seen in all three groups; however, the depression was significantly greater following hypothermic ischemia than following cardioplegia with either nifedipine or its carrier. The mean recovery value of stroke volume was highest in the nifedipine group, but this difference between nifedipine and its carrier alone did not reach statistical significance. Coronary blood flow, myocardial oxygen consumption, lactate extraction, and tissue gases failed to substantiate a significant benefit when nifedipine was compared with its carrier alone. We conclude that under these hypothermic conditions, no proven statistically significant advantage was noted in the nifedipine group when compared with the nifedipine carrier group in swine. However, both nifedipine and the carrier were superior as a myocardial preservative when compared with hypothermic ischemic arrest alone.

Naloxone: ineffective in improving cardiac performance after hypoperfusion in swine.

A study was done to measure beta-endorphin immunoreactivity (beta-EI) in swine subjected to cardiopulmonary bypass at normal aortic perfusion pressures and during low-flow states such as can occur with shock. Fifteen pigs, divided into three groups of five each, were placed on total and right heart bypass and perfused as follows: group I, normal blood pressure (80 mmHg); group II, low blood pressure (45 mmHg); and group III, low flows (25 ml/kg/hr). beta-endorphin immunoreactivity was assayed six times during the procedure. Ventricular performance was evaluated by measuring stroke volume (SV) while controlling preload, afterload, and heart rate. Determinations of SV were made at the beginning of bypass, after a 1-hr pump run, and after administration of naloxone (1.1 mg/kg). There were no significant changes in beta-EI in any of the groups during the study. The initial SV in group III (23 +/- 6 ml) decreased significantly (p less than 0.05) after 1 hr of decreased cardiac perfusion (8.0 +/- 7 ml) and was not improved by naloxone (5.0 +/- 7 ml). Ventricular performance was not improved in any group following naloxone administration. In our study, naloxone administered to swine following inadequate myocardial perfusion did not effect a significant cardiac hemodynamic response.

Amiodarone-digoxin interaction. Clinical and experimental observations.

Twenty-two patients were given amiodarone for refractory cardiac arrhythmias, and pre- and post-amiodarone serum digoxin levels were studied. The interval between pre- and post-amiodarone serum digoxin levels ranged from five days to nine months (mean interval, seven weeks). The mean (+/- SD) pre-amiodarone serum digoxin level was 1.0 +/- 0.4 ng/ml, and the post-amiodarone serum digoxin level was 1.9 +/- 0.8 ng/ml (p less than .001). To develop an animal model for study of the digoxin-amiodarone interaction, 18 pigs were given digoxin for a four-week period. Half of the animals were given amiodarone as well as digoxin for the last two weeks of the study. At the end of the initial two-week period, there was no difference in serum digoxin levels between the two groups. At the end of the second two-week period, the serum digoxin level in the group receiving digoxin alone was 0.6 +/- 0.2 ng/ml, and the serum digoxin level in the group receiving the digoxin and amiodarone was 1.2 +/- 0.6 ng/ml (p less than .01). These data confirm the presence of an amiodarone-digoxin interaction in man and show that the pig is an appropriate model for study of this clinical phenomenon in the animal laboratory.

Effectiveness of stroma-free hemoglobin solution as seen in a right heart bypass swine model.

To determine if tolerance to severe anemia (Hct less than or equal to 10%) might be improved with stroma-free hemoglobin solution (SFH), 15 swine were placed on normothermic right heart bypass (RHBP) for evaluation of stroke volume (SV), coronary blood flow (CBF), arterial-coronary sinus oxygen content difference S(a-cs)O2, and myocardial oxygen consumption (MVO2) during a control period at a hematocrit (Hct) level of 30%. These 15 animals, divided into three equal groups, subsequently underwent exchange transfusion either to a Hct of 5% using 7% SFH (group 1), or to a Hct of 5% (group 2) or 10% (group 3) using 7% bovine albumin solution. All tests were repeated during these experimental conditions. Myocardial performance after albumin solution exchange was sustained on RHBP in only 1 of 10 animals. SFH animals (group 1) had a significant drop in SV at 14 torr after exchange (20 +/- 3 ml vs 10 +/- 4 ml, p less than 0.025), but this 50% performance level could be sustained. CBF rose and MVO2 fell in all groups, although the statistically nonsignificant mean differences were less with SFH. S(a-c)O2 fell significantly (p less than 0.05) with albumin solution (group 2 7.3 +/- 1.4 vs 2.2 +/- 0.2, group 3 8.9 +/- 2.0 vs 3.8 +/- 1.0), and nonsignificantly with SFH (5.6 +/- 0.7 vs 4.1 +/- 1.4). Although myocardial performance decreased with SFH, the authors believe these comparative results support the use of SFH at an Hct of 5%.

Extending the limits of hemodilution on cardiopulmonary bypass using stroma-free hemoglobin solution.

Ten swine were subjected to exchange transfusion to a hematocrit level of 5% with either stroma-free hemoglobin solution (SFHS) or 7% albumin solution. Myocardial performance, oxygen kinetics, and myocardial metabolism were subsequently examined using a perfused, in situ, right heart bypass, swine heart model with control of preload, afterload, and heart rate. Animals were tested during a control period (hematocrit = 30%) and following exchange transfusion with either solution to a hematocrit level of 5%. We found that myocardial performance following albumin solution exchange could not be sustained on right heart bypass, and these animals had a stroke volume of zero at a left ventricular end-diastolic pressure of 14 torr. SFHS animals had a significant drop in stroke volume at 14 torr following exchange (20 +/- 3 versus 10 +/- 4, p < 0.025), but this 50% performance level could be sustained. Coronary blood flow rose and myocardial oxygen consumption fell in both groups, although the statistically nonsignificant mean differences were less with SFHS. Arterial-coronary sinus oxygen difference fell significantly (p < 0.05) with albumin solution (7.3 +/- 0.8 versus 2.2 +/- 0.2) and nonsignificantly with SFHS (5.6 +/- 0.4 versus 4.1 +/- 0.7). Lactate production occurred in both groups, but was greater with albumin (34% +/- 6%) than with SFHS (3% +/- 16%). No changes in myocardial tissue gasses were noted in either group. Although myocardial performance decreased and some lactate production occurred with SFHS, we believe these comparative results provide promise in the eventual utilization of an oxygen-carrying agent such as SFHS to extend the limits of hemodilution to a hematocrit value of 5% or less.

Treatment of esophageal carcinoma: a retrospective review.

Two hundred fourteen patients underwent treatment for carcinoma of the esophagus between January, 1950, and July, 1978, with an over-all 5 year survival rate of 1.9%. Forty-six patients (21.5% of series) underwent esophageal resection with either esophagogastrostomy (37 patients) or colon interposition (nine patients). The operative mortality rate was 18.9% for the esophagogastrectomy group and 33% for the colon interposition patients. "Curative" resections resulted in a 14.3% 5 year survival rate. One hundred twenty-seven patients (59.3% of series) were treated by irradiation therapy, with a mean survival time of 9.6 months for patients receiving "curative" dosage (over 4,500 rads). There were no 5 year survivors in this group. Palliative procedures, such as feeding gastrostomy and palliative (less than 4,500 rads) irradiation therapy, contributed little to patient comfort or survival. We favor a palliative approach to the treatment of esophageal carcinoma and believe that, when possible, esophageal resection with esophagogastrostomy is the preferable form of therapy and offers an occasional cure.

The importance of hyperkalemia in a cold perfusion solution: a correlative study examining myocardial function, metabolism, tissue gases, and substrates.

Twenty-four pigs were studied to assess the effect of potassium in a cardioplegic solution on the ability of the swine myocardium to maintain functional and metabolic integrity following induced ischemia. The pigs were evaluated on total and right heart bypass with measurement at normothermia and after a one-hour intervention of stroke volume (SV), coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and lactate extraction. Myocardial tissue gases (PmO2 and PmCO2) were continuously monitored and, at the conclusion of the procedure tissues were analyzed for adenosine triphosphate (ATP). There were five interventions: (1) hypothermic perfusion (28 degrees C) (Group 1); (2) hypothermic ischemia (28 degrees C) (Group 2); and hypothermic ischemia with a cardioplegic solution (nonlactated Ringer's solution, pH 7.4, 4 degrees C) using (3) normokalemia (4 mEq of potassium chloride/L, 300 mOsm/L (Group 3), (4) hyperkalemia (43 mEq of KCl/L, 390 mOsm/L) (Group 4), and (5) normokalemia with increased osmolarity (3.6 mEq of KCl/L, 400 mOsm/L) (Groups 5). A significant decrease in SV and elevation in peak PmCO2 were seen in all groups subjected to ischemia except those protected with hyperkalemic solution. We conclude that the presence of hyperkalemia in a cold root perfusion solution provides better myocardial protection than cold root perfusion alone. Furthermore, potassium arrest appears to be more protective than coronary perfusion at 28 degrees C.

Postoperative chylous pseudocyst.

A 59-year-old man underwent resection of aneurysm of the descending thoracic aorta with graft replacement. A postoperative chylothorax was managed by nonsurgical means and subsided. Subsequently, an expansile mass appeared in the left side of the chest and was surgically removed. This was found to be a chylous pseudocyst. Management of chylothorax and the details of this unique case are described.

Changes in the manufacture of expanded microporous polytetrafluoroethylene: effects on patency and histological behavior when used to replace the superior vena cava.

Polytetrafluoroethylene (PTFE) has been used clinically and experimentally as a vein substitute. Since its introduction, changes have been made in the manufacture of the material. This study was designed to evaluate the effects of pore size (fibril length), PTFE cover, and spiral tube support on long-term patency and histological behavior when this material is used as a replacement for the precava in the dog. A graft of 30-mu pore size has adequate fibroblastic ingrowth, a neointima of 200 mu or less, and the best long-term patency. The PTFE cover results in less fibroblastic involvement of the prosthetic graft and prevents late occlusion caused by transmural fibrosis in the 90-mu graft. The spiral support does not affect patency and may be indicated when external pressure on the tube must be avoided.

Gore-Tex grafts for replacement of the superior vena cava.

In an effort to evaluate polytetrafluoroethylene (Gore-Tex) as a replacement for large veins, tubular grafts of the material were substituted for the precava in 33 mongrel dogs weighing 15 to 30 kg. Thirteen dogs had grafts 10 cm long by 12 mm wide with a 15-to 30 micron pore size; 15 dogs had grafts of the same length and width from 90-micron pore size material; and 5 dogs had grafts 5 cm long by 12 mm wide, of 90-micron pore size Gore-Tex. The effect of Gore-Tex tubes with and without spiral support and the differences in anatomical positions of the grafts were evaluated in terms of patency. Dogs were killed if a venogram showed occlusion of the graft. Twelve dogs survived 90 days; the longest survivor was killed at eleven months. At postmortem examination, the graft was patent but extremely narrow at the atrial end. Modification in the fabrication of Gore-Tex may eliminate factors contributing to graft failure; experiments longer than 90 days are necessary to evaluate Gore-Tex as a large vein replacement material. The 90-micron pore size material used in this experiment was unsuitable as a canine venous substitute.

Surgical management of pectus deformities.

We analyzed the long-term results in 87 patients who had pectus deformities repaired at Fitzsimons Army Medical Center during the period 1953 to 1975. Seventy-one patients had operations for correction of pectus excavotum; 16 had pectus carinatum deformities repaired. A variety of surgical techniques was used in these patients. Our findings show that in excavatum deformities the best results were obtained by removing all deformed cartilage, mobilizing the sternum, using an anterior osteotomy, and stabilizing the chest with a metal strut (which was removed after one year). For carinatum defects, the Ravitch procedure has produced good results. We are encouraged to be more aggressive in advocating repair of the deformities, not only for cosmetic results but because the patients seem to feel healthier both physically and mentally after repair. For these reasons we advocate operation for pectus deformity as any age.

Congenital aneurysm of the sinus of Valsalva protruding into the left ventricle. Review of diagnosis and treatment of the unruptured aneurysm.

During a routine physical examination, a 34-year-old man, in apparent good health, had an electrocardiogram which revealed left axis deviation. Cardiac evaluation disclosed mild aortic regurgitation and left anterior fascicular block. Nine months later, the patient was admitted to the critical care unit after he had experienced cardiac arrest while jogging. Angiograms demonstrated a large unruptured aneurysm in the right coronary sinus of Valsalva protuding into the left ventricle. Echocardiographic manifestations also suggested also suggested a sinus of Valsalva aneurysm. The defect was repaired through an aortic approach. The aneurysmal sac was emptied and the neck sutured securely. Twenty-two months postoperatively, the patient continues to be asymptomatic. We anticipate that this will decrease the threat of recurrent arrhythmias..

Revascularization of the heart through the coronary veins.

Fifty-six dogs were used in a study to evaluate perfusion of the left anterior descending vein by the internal mammary artery in hearts with normal coronary arteries and those with ligated desending coronary arteries. Perfusion of the myocardium with arterial blood through the cardiac veins offers minimal immediate protection from infarction, as evidenced by light and electron microscopy studies. This protection is of short duration due to intimal fibrosis and luminal stenosis or obstruction of the perfused veins. Nineteen animals in which the coronary vein was perfused and the corresponding coronary artery was not ligated died within sixty hours from the time of operation. Pathological examination revealed patent grafts in all the animals. There was marked congestion of the myocardium with petechial hemorrhages over the surface of the heart. No evidence of myocardial infarction was found.