The use of insulin and glucose during resuscitation from hemorrhagic shock increases hepatic ATP

BACKGROUND

Hemorrhagic shock produces a marked decrease in hepatic ATP, adenylate energy charge, and total adenosine nucleotides. This is followed by slow recovery to normal levels after resuscitation. Nucleotide metabolites are increased following shock and resuscitation. Previous experimental work has shown that supraphysiologic doses of insulin have salutary effects in animals with hemorrhagic shock and in cardiac patients. It appears that insulin causes increased availability of glucose and energy-producing substrates. This study examined whether resuscitation with glucose and insulin after hemorrhagic shock would alter the changes previously seen to occur in hepatic ATP levels, adenylate energy charge, or nucleotide metabolites.

METHODS

Male Sprague-Dawley rats were bled to a mean arterial blood pressure of 40 mm Hg for 30 min. They were then resuscitated with the shed blood and one of three fluids: (1) lactated Ringer's, (2) lactated Ringer's with 10% glucose, (3) lactated Ringer's with 10% glucose + 6 units/kg regular insulin. Liver biopsies were obtained prior to shock (baseline), after 30 min of shock (shock), and 90 min after resuscitation (90 min). Tissue levels of ATP, ADP, AMP, adenosine, inosine, hypoxanthine, and xanthine were measured. Serum at 90 min was evaluated for potassium, glucose, and tumor necrosis factor alpha (TNF-alpha).

RESULTS

The insulin-treated group had significantly increased hepatic ATP and energy charge following resuscitation compared with the other two groups. The insulin group also exhibited significant hypoglycemia. Total adenine nucleotides (ATP, ADP, and AMP) were significantly elevated 90 min postresuscitation in the insulin group. Mean blood pressures throughout the experiment were not significantly different among groups. TNF-alpha was highest in the insulin-treated group, but this was not significant.

CONCLUSIONS

Resuscitation with insulin and dextrose significantly increased hepatic ATP and adenylate energy charge after hemorrhagic shock in rats. Total nucleotide pool levels were not different between groups, indicating that there was a shift of the equilibrium away from the metabolites toward ATP and ADP in the insulin-treated group. Insulin treatment had no significant effect on blood pressure or TNF-alpha. However, it caused significant hypoglycemia and hypokalemia.

Low falls: an underappreciated mechanism of injury

OBJECTIVE

This is a retrospective study designed to evaluate the pattern and severity of injuries that result from low falls, defined as falls from less than 20 ft, subsequent mortality, and requirements of hospital resources. Our hypothesis is that many of these injuries, even without cardiopulmonary instability, are worthy of trauma center care.

METHODS

The records of all patients entered into the hospital trauma registry at an urban Level I trauma center during the years 1991 through 1997 who suffered low falls and who either died after admission or were hospitalized for at least 3 days were reviewed. Patients suffering isolated hip fractures were excluded. One hundred seventy-six patients constituted the study population. This group accounts for about 2% of all admissions for falls at our institution. Patterns of injury were examined. Age, mechanism of injury, Injury Severity Score (ISS), and cardiopulmonary or neurologic instability on admission were documented. Mortality, length of intensive care unit and hospital stays, as well as billed hospital charges, were reviewed.

RESULTS

The majority of patients (62%) were younger than 50 years. Sixty patients had ISS >15 and 116 patients had ISS >9. Sixty patients had multisystem injuries requiring specialty care. Head injuries were found in 81 patients (35%), and vertebral fractures or spinal cord injuries were found in 49 patients (22%), including 9 quadriplegics and 5 paraplegics. There were seven patients with intra-abdominal injuries (five spleen and two bowel injuries). There was one patient with a rupture of the thoracic aorta. Seventeen patients had deteriorating neurologic or pulmonary function on arrival, but the majority (90%) were stable. Of the 159 "stable" patients, 48 suffered head injuries, 7 were quadriplegic, and 3 were paraplegic. All intra-abdominal injuries were in this group. Overall, 14 of 176 patients (8%) died. Seven deaths were in patients older than 60 years, and seven deaths were in younger patients (p = 0.04). The majority of deaths (9 of 14) were from head trauma. Care in the intensive care unit was required in 92 of 176 patients. Nine patients had billed charges exceeding $100,000.

CONCLUSION

Low falls can cause significant injuries, most commonly to the head and spine. Based on mechanism of injury alone, patients injured in low falls might not be taken to trauma centers. We have found, however, that many of these patients sustain serious multisystem injuries, even though they are stable initially. Although these patients represent only a fraction of those who fall, our study would support adjustment of triage guidelines to recommend transport of such patients, particularly elderly patients, to trauma centers.

Changes in adenine nucleotides during hemorrhagic shock and reperfusion

Certain tissues are known to be susceptible to shock-induced damage: liver, small bowel mucosa, and small bowel wall. This study was done to assess the changes in adenine nucleotides induced by hemorrhagic shock. Male Sprague-Dawley rats (n = 21; 300-350 g) were anesthetized with sodium pentobarbital (50 mg/kg, ip) and mechanically ventilated. The external jugular vein and common carotid artery were cannulated. Laparotomy was done. Hemorrhagic shock was induced by withdrawing blood into a heparinized syringe until a mean arterial blood pressure of 40 mm Hg was obtained and was maintained for 30 min by continued withdrawals. Shed blood was then reinfused through the venous catheter. No additional fluid was administered. The animals were observed for another 60 min. Throughout the procedure, biopsies were taken of liver and small bowel. The small bowel biopsies were separated into mucosal and wall fractions. Nucleotides were extracted. ATP, ADP, AMP, adenosine, inosine, xanthine, and hypoxanthine were measured with gradient HPLC. Cellular ATP concentrations decreased significantly during shock (P < 0.05). Liver ATP dropped from 8.93 +/- 0.55 to 2.91 +/- 0.16 micromol/g dry tissue (mean +/- SEM) (33%), small bowel mucosal ATP from 9.40 +/- 1.04 to 3.26 +/- 0.21 (35%), and small bowel wall ATP from 5.47 +/- 0.36 to 2.74 +/- 0.18 (50%). The nucleotide response to shock in small bowel mucosa was closer to that of liver than to that of small bowel wall. After reperfusion, ATP levels were partially restored in liver, small bowel mucosa, and small bowel wall, but not to preshock values. All of the metabolites (adenosine, inosine, hypoxanthine, and xanthine) increased during shock (P < 0.05), and did not return to preshock levels after reperfusion. The abnormalities in ATP and its metabolites, and their persistence after reperfusion, suggest a possible mechanism for the production of postshock damage.

Infectious sequelae in the use of polyglycolic acid mesh for splenic salvage with intraperitoneal contamination

Salvage of the injured spleen is important in the trauma patient. Loss of the spleen can result in both early and late infectious complications due to immunologic and phagocytic deficits. Splenic salvage techniques include the use of polyglycolic acid (PGA) mesh to wrap and tamponade the damaged and bleeding spleen. However, the use of mesh may increase the incidence of infection in the presence of intraperitoneal contamination. We examined whether mesh in the contaminated field increases the infection rate compared to splenectomy in a murine model. Sixty male Sprague-Dawley rats were divided into three groups of 20 each: splenectomy, splenic wrap with PGA, and control (with splenic mobilization). All rats were subjected to a standard inoculum of enteric bacteria at the time of celiotomy. Sixteen (80%) of the splenectomy rats, 10 (50%) of the PGA mesh wrapped rats, and four (20%) of the control rats expired (P < 0.5). In surviving rats, necropsy at 7 days demonstrated abscess formation in all four (100%) of splenectomy, four of 10 (40%) in PGA mesh wrapped, and two of 16 (13%) of control rats. All of the abscesses in the wrap group involved the mesh. Overall infection rates (including fatal peritonitis, abscess formation, and empyema) were 100% for splenectomy, 75% for PGA mesh wrapped, and 30% for control rats (P < 0.05). We conclude in this experimental model that the use of PGA mesh wrap does increase susceptibility to infection, but much less so than splenectomy in the presence of intraperitoneal contamination.

Peripheral nerve elongation with tissue expansion techniques

Elongation of peripheral nerves would facilitate the repair of peripheral nerve injuries. The purpose of this study was to determine the efficacy of nerve expansion and the effect of different levels of intraluminal expander pressure upon nerve conduction. A 2-mL Silastic expander was placed under one sciatic nerve of adult male rats. The other nerve served as a control. Electroneuromyography (ENMG) was done at the time of initial expansion in seven animals. At 40 mm Hg expansion pressure a significant change in latency was found with an increase of 17% +/- 5%. Expansion was carried out for 14 days in two groups of seven rats, group I at 20 mm Hg and group II at 40 mm Hg. Length gain on the expanded side was 30% in group I and 40% in group II. No significant changes in latency or velocity were found after expansion. We conclude that nerves can be expanded at low pressures with no significant conduction changes but long-term recovery of histologic changes needs to be evaluated.

Caloric and nitrogen balances as predictors of nutritional outcome in patients with burns

Measurement of energy expenditure with indirect calorimetry allows determination of caloric balance. The present study was done to determine the predictive value of caloric and nitrogen balances for nutritional outcome. Energy expenditure was obtained weekly and interpolated between measurements for daily caloric balance. Nitrogen balance was obtained weekly. Because nitrogen output fluctuated, interpolation of daily values was not possible. Nutritional outcome was defined by whether body weight was lost or maintained and by levels of visceral proteins (albumin, prealbumin, and transferrin). The study group included 12 patients with 7% to 82.5% total body surface area burns. Eleven patients survived their burn injuries, and one died of congestive heart failure at 38 days, after her burn wounds had healed. Nine patients had good nutritional outcomes (group 1) and three had poor nutritional outcomes (group 2) (including the one who died). Nitrogen balance was 1.3 +/- 1.0 gm/day in group 1 and 4.5 +/- 1.7 gm/day in group 2 (mean +/- SEM; p > 0.10). Caloric balance was 515 +/- 130 kcal/day in group 1 and -667 +/- 140 in group 2 (p < 0.001). Caloric balance was significantly different between the two groups, whereas nitrogen balance was not. Caloric intake correlated positively with nitrogen intake (r = 0.92). Nitrogen intake was 16% of total caloric intake. Nitrogen intake from blood products was appreciable and averaged 15% of total nitrogen intake (range, 0% to 47%); 11.3 +/- 1.6 gm/day in group 1 and 14.8 +/- 3 gm/day in group 2 (p > 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Variability of the Harris-Benedict equation in recently published textbooks

The Harris-Benedict equation, as cited in a selection of textbooks of medicine, surgery, and nutrition, was compared with the original monograph published by the Carnegie Foundation. A significant amount of variation was found in published versions of this equation. Of 24 published versions, eight were sufficiently variant to produce errors of 7% to 55% in calculations of nutrition requirements. The error is usually in the constant term for one of the two Harris-Benedict equations. Either the constant term for men is increased to a value approximately the same as for women, or the constant term for women is reduced to be approximately equal to that for men. The primary reason appears to be the lack of availability in medical libraries of the original Carnegie Foundation publication by Harris and Benedict.

A prospective study of incisional time, blood loss, pain, and healing with carbon dioxide laser, scalpel, and electrosurgery

Carbon dioxide laser incisions are reported to be less painful, less bloody, and less prone to seroma formation and to heal better than scalpel or electrosurgical incisions. We compared all three modalities in a prospective randomized study of cholecystectomy incisions. Time required for the incision and incisional blood loss was less with electrosurgery than with the carbon dioxide laser or scalpel. Postoperative pain and wound healing, however, were the same for all three techniques. The carbon dioxide laser appears to offer no advantage over conventional means of making a standard incision.

Nutritional support in the injured patient

After injury, the stress reaction causes hypermetabolism and consequent depletion of the body's tissues. Nutritional support should be begun early and should be given by the enteral route if possible. New developments may allow the modulation of the stress and immune responses by nutrient therapy.

Advanced techniques in thoracic trauma

Technologic aid is available for the three central problems of hemorrhage, lung damage, and cardiac damage. Autotransfusion, new modes of ventilator support, extracorporeal oxygenation, balloon pumping, and left ventricular assist are available for the trauma patient. The author explains these new devices and their role in thoracic trauma cases.

Intrathoracic and intravascular migratory foreign bodies

Intrathoracic and intravascular migratory foreign bodies are a small but distinctive subgroup of missile injuries. The intravascular bullet embolus can be treated like arterial or venous emboli of any other sort and removed as indicated. Wandering bullets in body cavities should be removed when they need to be, just like bullets imbedded in the body in a fixed position. And, contrary to the popular belief, very few bullets wander.

Detection thresholds of nonocclusive intestinal hypoperfusion by Doppler ultrasound, photoplethysmography, and fluorescein

Because clinical assessment of bowel viability is unreliable, other methods of determining intestinal perfusion have been recommended. Since none of these quantifies intestinal blood flow, we measured flow at the detection thresholds of Doppler ultrasound, photoplethysmography, and intravenously administered fluorescein, perfused the intestines at these threshold levels, and assessed histologic evidence of ischemic damage. The intestines of five anesthetized dogs were perfused for 4 hours via an in-line pulsatile extra-corporeal circuit assembled between the iliac and superior mesenteric arteries at either relatively physiologic (approximately 20 ml/min/kg body weight) levels or reduced levels representing the flow detection thresholds of Doppler ultrasound or photoplethysmographic probes (approximately 4 ml/min/kg). Intravenously administered fluorescein was detected at even lower perfusion levels (approximately 2.1 ml/min/kg). Clear-cut ischemic changes were documented histologically in all subjects perfused at Doppler/PPG flow detection thresholds but in none of those perfused at normal levels. We conclude that threshold blood flow detection by any one of these methods, especially fluorescein, occurs at levels inadequate to guarantee tissue viability.

Prevention of suction-induced gastric mucosal damage in dogs

Gastric suction has traditionally been available in three modes: continuous, sump, and intermittent. An intermittent air injection suction system (IAIS) has been developed in which small (20 to 30 mm) amounts of air are injected two to three times a minute. Very low (20 mm Hg) suction levels are applied. The hypothesis of the present study is that such a device will prevent suction-induced gastric mucosal damage, probably produced by suctioning of mucosa into the holes of the NG tube. IAIS should prevent this by physically expelling the mucosa out of the holes and allowing use of much lower suction levels. In 25 animals, gastric suction for 24 h in anesthetized dogs routinely produced ulcers. However, IAIS produced significantly fewer ulcers and in fewer animals. In 37 animals, the effectiveness of suction, measured by recovery of fluid instilled in the stomach, and the tendency of the tube to block were studied. Effectiveness was the same for all modes studied. Blockage was significantly less with IAIS.

Cardiac dysrhythmias in the acute setting: pathophysiology or anyone can understand cardiac dysrhythmias

Cardiac dysrhythmias are easy. Unlike the lung (which has formidable neuroendocrine, metabolic, and respiratory responsibilities), the heart is simple. It is an innervated muscular pump. A resting Purkinje or ventricular muscle cell membrane maintains a charge of about 90 millivolts. The five phases of a cardiac action potential are similar to the action potential in skeletal muscle, however, the cardiac action potential lasts a hundred times longer. When sodium specific "fast" channels and calcium specific "slow" channels open, positive ions rush into the myocardial cell, thus causing rapid membrane depolarization. In order to produce an action potential, some stimulus must decrease the membrane potential from -90 millivolts to "threshold" or -60 millivolts. Purkinje fibers do not have a stable phase for diastolic potential. These fibers continuously depolarize during diastole. Hypoxemia or hypokalemia may exacerbate this diastolic depolarization, thus promoting "hyperexcitability" or "automatic" ectopy. When myocardium is damaged, characteristically with myocardial ischemia, rapid conduction of cardiac impulses may be slowed dramatically. Very slow impulses may course through muscle such that by the time the activation wave front returns to the initiating site, this origin has had a chance to repolarize. This is the basis for re-entrant dysrhythmias. All cardiac dysrhythmias are automatic, re-entrant or both.

Cardiac dysrhythmias in the acute setting: recognition and treatment or anyone can treat cardiac dysrhythmias

The two primary goals in dysrhythmia therapy are: to control the ventricular rate (between 70 and 100 beats per minute) and to maintain sinus rhythm. Maintenance of sinus rhythm is definitely secondary. If a patient is hemodynamically unstable, but has a ventricular rate between 60 and 100 beats per minute, the trouble is almost certainly not due to the cardiac rhythm. Normal conduction velocity is fast. An impulse is transmitted by healthy Purkinje fibers at 2 to 3 meters per second. This means that the entire ventricle, when activated by the Purkinje system, is activated in 80 milliseconds. When a superventricular impulse is transmitted to the ventricles via the A-V node, the ventricle should be activated (depolarized) in less than 80 milliseconds. Conversely, if an impulse is generated at an ectopic ventricular site, it does not access the high velocity Purkinje system as rapidly. A ventricular origin beat (PVC) thus, takes longer to activate the entire ventricle. The QRS is, therefore, longer (or wider). A wide QRS signifies aberrant ventricular conduction. When a dysrhythmia originates above the A-V node, the therapy is pharmacologic A-V nodal blockade (verapamil). When a dysrhythmia originates below the A-V node, therapy is pharmacologic (Lidocaine) or electrical (cardioversion). If uncertain or a patient is unstable, cardioversion is always acceptable. Thus; with an unstable patient, proceed immediately to cardioversion; with a narrow complex tachycardia (superventricular) proceed to verapamil; and with a wide complex (ventricular) tachycardia give Lidocaine and proceed to cardioversion.

The protective action of allopurinol in an experimental model of haemorrhagic shock and reperfusion

Haemorrhagic shock was induced in anaesthetized, open-chest dogs by controlled arterial bleeding, sufficient to reduce and maintain mean arterial blood pressure at 40 mmHg for 30 min. The blood volume was then restored to the pre-shock level by rapid, intravenous reinfusion of the blood shed during the shock period. Haemorrhagic shock produced significant haemodynamic changes, characterized by a marked depression of myocardial function. Cardiac output (1226 +/- 57 ml min-1), peak aortic blood flow (6030 +/- 383 ml min-1) and maximum rate of rise of left ventricular pressure (2708 +/- 264 mmHg s-1) were all reduced by more than 50%. The haemodynamic profile was markedly improved by reinfusion of shed blood but this improvement was not sustained. There was a gradual decline such that 50% of the untreated animals suffered complete circulatory collapse and death between 60 and 120 min following reinfusion. Neither haemorrhagic shock, nor reinfusion of shed blood produced any consistent or significant changes in the myocardial adenine nucleotide pool. The ATP, ADP and AMP levels were, respectively, 25.9 +/- 4.2; 15.6 +/- 1.0; 4.3 +/- 1.9 nmol g-1 protein, before haemorrhagic shock; 21.6 +/- 3.4; 21.5 +/- 2.5; 10.2 +/- 2.7 nmol g-1 protein, after 30 min haemorrhagic shock; and 29.9 +/- 3.9; 16.5 +/- 1.2; 4.2 +/- 1.1 nmol g-1 protein, 60 min following reinfusion of shed blood. Pretreatment with allopurinol (50.0 mg kg-1 i.v.), 60 min before inducing haemorrhagic shock, had no significant effect upon the haemodynamic response to shock, but did prevent the gradual decline seen following reinfusion in the untreated animals. All of the allopurinol-treated animals displayed significantly better haemodynamic profiles than the untreated animals, furthermore, there was a 100% survival rate in this group. 5 Allopurinol had no significant effect upon the myocardial adenine nucleotide pool either during haemorrhagic shock or following reinfusion of shed blood.

Delayed staple penetration of the heart: transthoracic migration with late tamponade

Most foreign bodies in the chest do their damage at the time of injury. While needle-like objects may migrate (6), delayed intrathoracic injury is rare. Delayed transthoracic penetration of the heart by a staple is reported, and is felt to be unique because acute hemopericardium resulted 30 days after the time of initial injury. The principles of recognition of pericardial tamponade, initial stabilization with periocardiocentesis, and immediate exploration are emphasized.

Aortocardiac fistula with aortic valve injury from penetrating trauma

A patient with a delayed aorto-right ventricular fistula and aortic valve injury after penetrating trauma is reported, and 17 similar additional cases from the literature reviewed. By examining the aortic root of adults with normal cardiac anatomy at autopsy, we defined the target area for these injuries as a 2 X 2 cm contact surface between the aorta above the right coronary cusp and the right ventricular outflow tract below the pulmonary valve. Five of the 18 patients required emergency exploration due to hemodynamic instability. Life-threatening sequelae (hemorrhage and cardiac tamponade) result from the external injury rather than the intracardiac component. Intracardiac damage is most commonly manifested as the delayed recognition of a cardiac murmur and some degree of congestive heart failure, and when these appear one must suspect intracardiac trauma. We recommend cardiac catheterization and elective repair, maintaining control of both ends of the intracardiac fistula with bolstered suture. Aortic valve injury can often be primarily repaired. Patients with combination aortic valve and aortocardiac fistula injuries, more so than those with a single intracardiac lesion, fail with nonoperative management. Of the 18 patients, 17 underwent surgery. One of these died: the others did well during short-term followup (less than 1 year).

Comparison of total parenteral nutrition with 25 per cent and 45 per cent branched chain amino acids in stressed patients

Administration of total parenteral nutrition (TPN) solutions high in branched chain amino acids (BCAA) is thought to improve metabolic support during stress. This prospective, randomized, double blind study compared 45 per cent BCAA with 25 per cent BCAA in 12 patients. Seven patients had multiple trauma; two, gastrointestinal surgery; one, pancreatitis; and two, cirrhosis. The TPN regimen was 1.0-1.5 gm/kg/day amino acids and 30-45 glucose kcal/kg/day. The BCAA formula used was high in isoleucine and valine, but not leucine. Amino acid plasma levels, blood chemistries, 3-methylhistidine excretion, and nitrogen balance were studied. Control studies showed negative nitrogen balance (-7.1 +/- 2.9 gm) (mean +/- SEM), elevated insulin (61 +/- 21 microunit/ml), and elevated 3-methylhistidine (3MH) excretion (688 +/- 309 micromol); plasma leucine (93 +/- 11 nmol/ml) and isoleucine (37 +/- 23) were low, and valine (155 +/- 20) was elevated. Plasma methionine (40 +/- 9) and tyrosine (70 +/- 12) were high normal. Phenylalanine (85 +/- 5) was elevated. Both groups showed increased nitrogen excretion and positive nitrogen balance during the study (25 per cent, 2.0 +/- 1.4 gm/day; 45 per cent, 1.2 +/- 2.6 gm/day). Three-methylhistidine excretion changed little in either group (557 +/- 149, 414 +/- 91), insulin rose (135 +/- 27, 65 +/- 19), and plasma leucine (82 +/- 4, 71 +/- 9) changed little. Plasma isoleucine (51 +/- 3, 155 +/- 16) and valine (173 +/- 11, 691 +/- 23) both rose, more in the 45 per cent group. Methionine (67 +/- 12, 37 +/- 4) and tyrosine (51 +/- 6, 50 +/- 10) changed little.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated pulmonary vascular resistance in patients dying from multiple organ failure

Twenty-one patients with multiple organ failure were studied with hemodynamic monitoring. The five survivors were compared with the 16 nonsurvivors. Significant differences were found in the cardiac index (CI), the left ventricular stroke work index (LVSWI), and the pulmonary vascular resistance index (PVRI). The CI was higher in survivors (4.38 +/- 1.71) than in nonsurvivors (3.43 +/- 1.49). The LVSWI was also higher (43.0 +/- 16.8, 28.7 +/- 12.8) than in nonsurvivors (47.4 +/- 2.91). The PVRI was lower in survivors (168 +/- 122) than in nonsurvivors (474 +/- 291). It is postulated that the elevated PVRI in MOF is related to the adult respiratory distress syndrome.

Amikacin concentrations in serum following intraoperative irrigation of the pleura and peritoneum

Serum concentrations of amikacin following operative wound irrigation were studied in 17 patients having laporatomy and in eight patients having thoracotomy. Irrigation was done with 500 mg of amikacin in 200 ml of saline. The irrigant was reaspirated after 3 minutes. Measurement of amikacin in the irrigant allowed calculation of the retained dose. Serum levels were measured before surgery, and at 30 minutes, 60 minutes, 6 hours, and 12 hours following irrigation. Amikacin was assayed by a microbiological technique. The retained dose after peritoneal irrigation was 350 +/- 128 mg, and after pleural irrigation was 100 +/- 79 mg. The average maximum serum level in the peritoneal irrigation group was 9.4 +/- 6.7 gm/ml; in the thoracotomy group it was 3.5 +/- 1.7. Fourteen of the 17 laparotomy patients but only one of the eight thoracotomy patients had measurable plasma levels at 6 hours. Plasma half-life in the laparotomy group was 2.81 +/- 1.34 hours, and in the thoracotomy group 1.53 +/- 0.83 hours. Interoperative amikacin irrigation, even with immediate aspiration, results in significant absorption in both thoracotomy and laporatomy patients. There was less absorption and a shorter serum half-life in the thoracotomy patients.

Severe thoracic and abdominal injuries associated with lap-harness seatbelts

We report an unusual constellation of severe thoracic and abdominal injuries in a passenger restrained by a lap-harness seat belt during a high-speed automobile accident. This combination of injuries, which appears to have not previously been described, emphasizes the causative relationship of this protective device.

The effect of intravenous safflower oil emulsion on the clotting mechanism

A new fat emulsion for intravenous use, derived from safflower oil (Abbott Laboratories), was studied. The clotting mechanism was compared with a battery of tests performed during the infusion of total parenteral nutrition (TPN) using glucose alone and during infusion of TPN using both glucose and fat. Five adult surgical patients underwent TPN with 7.0 per cent amino acid solution for ten days, receiving glucose as their only nonprotein calorie source on days one, two, nine, and ten (40 kcal/kg/day). On days three through eight, 10 per cent fat emulsion (600-900 ml/day) was given each day to provide one-third of the nonprotein calories. Simplate bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen (Biuret method), platelet count, platelet aggregation, serum functional antithrombin, and viscoelastic curves were measured on days one, three, six, and ten. Some of these studies were abnormal at baseline and during the study. No significant changes were seen with fat emulsion infusion. The patients did not exhibit any evidence of clinical bleeding. This new intravenous fat emulsion did not appear to be associated with alterations in the clotting mechanism. However, two of five patients showed increases in serum triglycerides and one patient died during the study.

Factors influencing nutritional assessment in abdominal trauma patients

Previous work has shown that an abdominal trauma index (ATI) based on anatomic severity of injury reliably predicts complications following abdominal trauma, whereas the Prognostic Nutritional Index (PNI) does not. This study was undertaken to reconcile the disparity between the PNI and ATI as predictors of postoperative morbidity and mortality. Twenty-four patients undergoing immediate laparotomy following acute abdominal trauma were evaluated. Their mean age was 32.8 years (range 18-59 years); 18 were men. All patients underwent nutritional assessment within 12 hours of surgery. A statistical comparison of blood replacement, operating time, ATI, and PNI was performed. The mean PNI was 51 and mean blood replacement was 12.5 units. Using linear regression the PNI and amount of blood replacement correlated significantly (r = 0..44, p less than 0.05). Operating time and ATI did not correlate with PNI. In conclusion, the PNI was more strongly influenced by blood loss than severity of intraperitoneal injury. For this reason it is relatively ineffective in predicting complications following trauma.

A feasibility study of computer aided diagnosis in appendicitis

In this study, the hypothesis that computer aided diagnosis could enable a more accurate differentiation between patients with acute appendicitis and those with abdominal pain but normal appendixes was examined. A data base was established by analyzing the records of 476 patients having an emergency measure appendectomy during a five year period. There were 360 or 76 per cent with acute appendicitis, 98 or 20 per cent with normal appendixes and 18 or 4 per cent with other diseases requiring operation. The records were analyzed with regard to history, physical examination and laboratory findings. The data base was then divided randomly into two parts. Part 1 was subjected to univariate discriminant analysis, using the chi-square test. The only quantities which were significantly different between appendicitis and a normal appendix were sex, duration of symptoms, anorexia and vomiting. Multivariate discriminant analysis was used to derive an abdominal pain index which discriminated between appendicitis and a normal appendix with a sensitivity of 0.82 and a specificity of 0.39. Using the abdominal pain index to evaluate the patients in part 2 of the data base, 23 or 40 per cent of the 58 patients with a normal appendix would have avoided operation. However, 31 or 18 per cent of the 169 patients with appendicitis would have not been operated upon; three of those 31 had perforated appendixes. Computer aided diagnosis was no more effective than unaided clinical diagnosis in appendicitis.

Clinical evaluation of a low lint surgical sponge

To evaluate a new low lint, nonwoven surgical sponge material, a prospective, stratified, randomized, single blind study of 232 patients was carried out. Patients studied underwent thoracic, upper abdominal or lower abdominal operations. The new material, in the form of laparotomy pads and sponges, was compared with cotton gauze. Safety of the material was evaluated by a battery of biochemical and hematologic tests. No clinically significant differences were seen. Effectiveness was evaluated by measuring fluid absorption. The new material was significantly more effective than cotton gauze in both configurations studied. Since this article was completed, the sponge material has been refabricated into laparotomy pads which are appreciably softer and more comformable than the study pads. The newest revision has been cleared by the Food and Drug Administration for clinical use.

Thermokinetics of cold cardioplegic arrest

This study was designed to test the hypothesis that the rapidity with which the heart rewarms following cold cardioplegic arrest depends upon the technique of cannulation. In dogs, temperatures were monitored at multiple myocardial sites during rewarming, using four different cannulation techniques: caval cannulation with total bypass, caval cannulation with partial bypass, atrioventricular cannulation, and atrial cannulation. A mathematical model was constructed to facilitate analysis of the data, assuming that the rewarming process can be described by first order kinetics. Using this model, the half time of rewarming was defined as the time required for the myocardium to rewarm halfway from initial temperature to core temperature. Analyzing the several cannulation techniques in terms of the half time of rewarming, several conclusions were drawn: myocardial temperature distribution is non-homogeneous, rewarming is relatively rapid, partial bypass produces more rapid rewarming than total bypass, atrioventricular cannulation produces more rapid rewarming than either caval or atrial cannulation, and the principle routes of rewarming were from the posterior parieties and from blood entering the right side of the heart during partial bypass.

Vascular trauma in the groin: contrast between iliac and femoral injuries

Vascular injuries to the groin are common and often life-threatening. Injuries above the inguinal ligament, to the iliac system, are associated with a 37 percent mortality. Associated intraabdominal injuries are common. These patients must be identified promptly, given broad-spectrum antibiotics and taken immediately to the operating room for exploration through a midline incision. Injuries below the inguinal ligament are usually to the femoral vessels and are rarely fatal. These patients may be evaluated more extensively before leg exploration. Associated intraabdominal injuries are unusual, but disability from femoral fractures and nerve injuries are common.

Complications of tube thoracostomy for acute trauma

Closed tube thoracostomy is a common and very useful procedure in therapy of acute thoracic injury. However, it is not without risk. With aggressive use of this procedure in the emergency department, the incidence of technical complications was 1 percent. Our review suggests that complications can be further diminished by the routine use of large thoracostomy tubes that are placed well up on the chest after confirmation of an open pleural space, by avoiding the use of a trocar for tube placement, and by the use of a high volume, low pressure suction system. Empyema was the most common complication associated with tube thoracostomy after trauma. It occurred in 2.4 percent of the patients. Its exact causes is not known, and the role of prophylactic antibiotics needs to be established.

Temporary cardiac pacing in traumatic arrest victims

Temporary ventricular pacing was successfully employed in two patients suffering refractory bradycardia following traumatic cardiac arrest. The hemodynamic response to pacing was dramatic and both patients eventually recovered fully from an apparent moribund state. Cardiac pacing may be an effective adjuvant in the early resuscitation of the massively injured patient.

Nitrogen balance and electrolyte requirements in intralipid-based hyperalimentation

The present study was directed at determining whether or not a relatively low-calorie regimen in which 40 to 50% of the calories are provided as fat will produce positive nitrogen balance in most patients, and at establishing the electrolyte requirements for such a regimen. Clearly, the recommended regimen is successful in promoting nitrogen balance and provides adequate electrolytes. Further experience will be necessary to determine the place of intravenous fat emulsions in the clinical practice of total parenteral nutrition.

Hemorrhagic necrosis of pheochromocytoma associated with phentolamine administration

A case of ruptured pheochromocytoma is presented, the pathophysiology discussed, and the literature reviewed. Evidence is presented that the use of alpha-adrenergic blockade in general, and phentolamine in particular, may predispose to this complication. Twelve cases of massive hemorrhagic necrosis with or without rupture were found in the literature, including the present case. Six had no operation; one survived. Six had immediate operation; 4 survived. An additional case of hemorrhage into a small pheochromocytoma following phentolamine is presented. This tumor was neither ruptured nor massively necrotic, but the case supports the hypothesis that alpha-adrenergic blockade may cause hemorrhage within the pheochromocytoma.

Studies of plasma renin activity in coarctation of the aorta

Experimental and clinical studies were performed to assess the role of the renin-angiotensin system in producing hypertension in coarctation of the aorta. Basal and stimulated peripheral plasma renin activity were determined in the canine model and in four patients with coarctation. The animal studies showed no significant elevation of peripheral plasma renin activity (PPRA), and no increase in the response of PPRA to stimuli. The human studies showed a significant elevation in the response to PPRA to postural change and to exercise in three of four patients with coarctation, as compared to the same patients after correction of the coarctation. It is concluded that hyperactivity of the renin-angiotensin system is not the primary cause in coarctation hypertension in dog or man. It is nonetheless probable that the renin-angiotensin system has a role in coarctation hypertension, and further studies will be necessary to determine its place.

Nitrogen balance in postoperative patients receiving parenteral nutrition

Fifteen patients were given parenteral nutrition with hyperosmolar glucose during the postoperative period (days 1 to 5): nine received an average of 10.5 gm of nitrogen and 2,340 kilocalories/day, six were given an average of 5.9 gm of nitrogen and 1,600 kilocalories/day. Eight patients (controls) received no nitrogen and 520 kilocalories/day. The results of this study confirm our early findings that total parenteral nutrition is capable of reversing the negative nitrogen balance of the immediate postoperative period; this reversal depends on administration of adequate nitrogen and calories. In patients with moderate surgical procedures, at least 8 gm of nitrogen and 1,800 kilocalories/day are required to correct the negative nitrogen balance. When total parenteral nutrition is instituted, adequate nitrogen and calories should be given even if insulin is required to control hyperglycemia.

An assessment of the role of parenteral alimentation in the management of surgical patients

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