Protection against spinal cord ischemia with insulin-induced hypoglycemia

The effect of insulin-induced reduction in blood glucose to 65 +/- 20 mg/dl (mean +/- standard deviation) on recovery of electrophysiological function and extracellular lactate concentration was studied in a rabbit model of spinal cord ischemia. These results were compared to findings in animals with spinal cord ischemia that either were fasted overnight (fasted group: blood glucose 97 +/- 26 mg/dl) or had no pretreatment (control group: blood glucose 172 +/- 65 mg/dl). The aorta was occluded until the postsynaptic waves of the spinal somatosensory evoked potentials (SSEP's) had been absent for 20 minutes, a period of ischemia that produces paraplegia in 100% of untreated rabbits. The total aortic occlusion time was not significantly different in the three groups. Recovery of the SSEP's was significantly better in the insulin-treated animals than in the fasted or control animals. The N3 wave of the SSEP's, which has been found to correlate best with neurological recovery, returned to 65% +/- 48% of the preischemia amplitude in the insulin-treated animals, compared to 40% +/- 34% in the fasted group and 26% +/- 24% in the control animals. Extracellular lactate concentration in the spinal cord increased immediately after occlusion of the aorta, reached a plateau as the postsynaptic waves disappeared from the SSEP's, and then increased a second time during the first 15 minutes of reperfusion. The peak lactate concentration during ischemia and during reperfusion correlated with the preischemia glucose concentration (r = 0.60336 and r = 0.76930, respectively). Lactate concentration in the spinal cord was higher during ischemia and throughout the first 2 hours of reperfusion in the control and fasted animals than in the insulin-treated animals. During the 2nd hour of reperfusion, lactate concentration was significantly higher in the control animals than in the fasted animals. Reduction in blood glucose with insulin improves recovery of electrophysiological function after spinal cord ischemia, probably because of reduced lactic acid production, especially during the early reperfusion period.

The predictive value of cerebral anaerobic metabolism with cerebral infarction after head injury

Cerebral ischemia is a common mechanism of secondary brain injury following severe head injury. The cerebral metabolic rate of oxygen (CMRO2) and of lactate (CMRL), as well as cerebral blood flow (CBF) were measured daily for 5 days after head injury in 44 comatose head-injured patients to determine if metabolic changes could identify the patients who would develop cerebral infarction. Of 41 patients whose CBF remained at levels regarded as adequate to prevent infarction (CBF greater than or equal to 0.2 ml/gm/min), the six who showed a cerebral infarction on computerized tomography (CT) scans exhibited characteristic cerebral metabolic patterns: a CMRO2 of less than 0.6 mumol/gm/min on one or more of the days monitored, and markedly elevated cerebral lactate production (CMRL less than -0.06 mumol/gm/min) on Days 1 and/or 2 after injury. Patients who had no areas of infarction on serial CT scans typically had a CMRO2 and CMRL can be obtained at the bedside and can indicate the presence of an evolving ischemic infarct after head injury.

National survey of use of the Angelchik antireflux prosthesis

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Vagal function in achalasia of the cardia

Autonomic nervous function in achalasia of the cardia was assessed by measuring the response of the lower oesophageal sphincter to abdominal compression, the gastric secretory response to insulin-induced hypoglycaemia and the pulse rate variability with deep respiration. Twenty-eight patients with symptomatic achalasia and 24 age and sex-matched control subjects were studied. Rise in intra-abdominal pressure normally causes a rise in lower oesophageal pressure through a vagally-mediated mechanism. Before treatment this response was unimpaired in eight of 10 patients with achalasia. A sub-normal response was found in eight of 10 patients who had previously had pneumatic dilatation of the cardia and in three of four who had had a cardiomyotomy. These abnormalities reflected the effect of treatment in disrupting the sphincter rather than impairment of its innervation. The gastric acid secretory response to insulin-induced hypoglycaemia, expressed as a ratio of that to pentagastrin, was normal in each of the nine patients studied. Pulse rate variability with deep respiration, a test of cardiac vagal function, was normal in 22 of 25 patients studied. It is concluded that in achalasia the vagal trunks appear functionally intact and that the myenteric plexus lesion rarely affects the responsiveness of the lower oesophageal sphincter to increase in intra-abdominal pressure.

Biliary pharmacokinetics of sulbactam plus ampicillin in humans

The biliary pharmacokinetics of sulbactam and ampicillin was investigated in 19 patients with normal liver function who were undergoing surgery of the biliary tract. The combination of sulbactam (0.5 g) plus ampicillin (1 g) was given intravenously to five patients with T-tube drainage of the common bile duct. Mean peak concentrations of sulbactam (19.4 micrograms/ml) and ampicillin (471 micrograms/ml) in the bile occurred 0.5-1 hr after administration. Biliary excretion was estimated to account for approximately 0.24% of the sulbactam dose and 2.8% of the ampicillin dose. Fourteen other patients received the same dose of sulbactam/ampicillin immediately before elective cholecystectomy. Respective mean concentrations of sulbactam and ampicillin at the time of gallbladder removal were 4.3 micrograms/ml and 15.9 micrograms/ml in gallbladder bile and 6.3 micrograms/g and 7.7 micrograms/g in gallbladder wall tissue. These results, together with the antibacterial spectrum and potency of the combination, suggest that sulbactam/ampicillin is suitable for prophylactic use in biliary tract surgery.

Assessment of nutritional requirements of head-injured patients

A nomogram is presented for estimation of energy expenditure at the bedside in comatose patients during the first 2 weeks after brain injury. In analysis of 312 days of energy expenditure in 57 patients, a combination of Glasgow Coma Scale (GCS) score, heart rate (HR), and days since injury (DSI) was found with multiple regression analysis to provide good prediction of resting metabolic expenditure (RME) according to the following relationship: %RME = 152 - 14(GCS score) + 0.4(HR) + 7(DSI) (n = 111, r = 0.7, p less than 0.001). In non-comatose patients, predictive ability was less strong due to inability to measure truly rested values, but HR and GCS score could be used to predict energy expenditure by this relationship: %RME = 90 - 3 (GCS score) + 0.9 (HR) (n = 135, r = 0.47, p less than 0.001). In six patients, paralysis was found to decrease energy expenditure to between 100% and 125% of expected. Movement or stimulation had little effect on energy expenditure in patients who could localize stimuli but increased rested values by 20% in posturing patients. Analysis of fasted balance periods of nitrogen excretion in 22 patients based on 273 days of measurement showed a significant relationship between creatinine-height index (an index of muscle mass) and nitrogen excretion, but no relationship between nitrogen excretion and weight, temperature, and RME. Levels of retention of nitrogen with feeding could not be predicted by any of these variables. Feeding of the individual comatose patient is best guided at present by estimation of energy expenditure using a nomogram and periodic measurement of urinary nitrogen excretion.

Protection against experimental ischemic spinal cord injury

The authors have studied the protection against ischemic damage to rabbit spinal cord by pretreatment with agents that block neuronal activity and directly or indirectly reduce tissue metabolism. Hypothermia, thiopental, magnesium, lidocaine, and naloxone were used to pretreat the spinal cord prior to ischemia. Hypothermia and thiopental provided comparable protection: they each increased the duration of ischemia required to produce neurological deficits in 50% of the animals from 26 to 41 minutes. They also increased from 10 to 30 minutes the time that the postsynaptic waves of the spinal somatosensory evoked potential (SSEP) could be absent and the animal still have neurological recovery. Hypothermia and thiopental, when used together, increased the duration of ischemia required to produce neurological deficits to 57 minutes in 50% of the animals. Naloxone increased the duration of ischemia required to produce neurological deficits to 36 minutes in 50% of the animals, and increased to 20 minutes the time that the postsynaptic waves of the SSEP could be absent and the animal still have neurological recovery. Magnesium pretreatment improved neurological outcome, possibly by improving collateral circulation as the SSEP did not fail completely during aortic occlusion in all animals. Lidocaine was not beneficial, perhaps because of the prolonged hypotension that resulted.

Steroid administration and nitrogen excretion in the head-injured patient

The effect of steroid administration on metabolic rate and nitrogen excretion was examined in 20 head-injured patients alternately assigned to receive either methylprednisolone for 14 days or no steroid treatment. Although metabolic rate, caloric intake, and nitrogen intake were not different between the two groups, the patients who received steroids had a 30% higher excretion of nitrogen during the first 6 days after injury than did the patients not receiving steroids. All patients had an increase in nitrogen excretion through the 2nd week, peaking on Day 11. By Day 21 after injury, the patients had an average cumulative nitrogen loss of 162 gm and had lost an average of 5 kg body weight regardless of whether they had received steroids. Serum albumin levels decreased in the steroid-treated patients but returned to nearly normal by Day 21 in the untreated group. Immunosuppression, evidenced by a lower initial total lymphocyte count and a higher incidence of infections, was present in the steroid group; hyperglycemia requiring insulin treatment was more common in those patients.

Enteral hyperalimentation in head injury

The objectives of this study were to determine the ability of enteral hyperalimentation to meet the caloric and protein requirements in acute severe head injury, and to study the effect of increasing protein intake on nitrogen balance. This consecutive series of 20 patients suffered acute severe head injury and remained comatose for at least 24 hours. They were all without other major injuries, and were treated with steroids. These patients were randomly placed in two comparable treatment groups: one group was fed with an enteral formula containing 14% of its calories as protein and the other group received a formula containing 22% protein calories. Feedings were advanced to replace 140% of caloric expenditure measured by indirect calorimetry, averaging 3500 kcal/24 hr. Balance periods of the targeted intake were 7 days in duration, and were begun during the 1st week after injury for 65% of patients and in the 2nd week after injury for 35% of patients. The lower protein group received an average of 26.8 gm/24 hr of nitrogen, equivalent to 188 gm of protein, and the higher protein group 34.3 gm/24 hr, equivalent to 231 gm of protein. Nitrogen balance was -9.2 +/- 6.7 gm/24 hr in the lower protein group and -5.3 +/- 5.0 gm/24 hr in the higher protein group, but the difference did not reach statistical significance because of sample size and variability in extent of catabolism among patients. Despite the hyperalimentation, there was a mean negative cumulative nitrogen balance of 200 gm by the 2nd week after injury, and only three patients achieved net nitrogen equilibrium for the 7-day balance period. Despite enteral hyperalimentation, the patients' weight fell by 15% in the 2nd week, serum albumin was often decreased, and creatinine-height index decreased over time but remained in a normal range. Monitoring urinary urea nitrogen, which has been advocated as a generally available technique for measuring urinary nitrogen concentration, was found to be a poor measure of urinary nitrogen excretion. This work has demonstrated: 1) that high caloric and protein feedings may be delivered for prolonged periods enterally for most patients in the acute phase of head injury with few metabolic complications, and 2) that increasing the nitrogen content of feedings from 14% to 22% may somewhat improve nitrogen retention, although nitrogen equilibrium is seldom achieved.

Oxygen utilization and cardiovascular function in head-injured patients

Factors that influenced resting metabolic expenditure (RME) and the cardiovascular response associated with an elevated RME were examined in 55 patients with penetrating and closed head injuries who were kept normovolemic and hyperalimented during the acute phase of injury. The severity of the neurological injury had a strong effect on the RME; those with a GCS of 4-5 had the highest RME, 168 +/- 53% of that expected, whereas those with a GCS of 6-7 had a lower RME, 129 +/- 31% of that expected. Increased body temperature was associated with increased RME by 45%/degrees C in patients with a GCS of 4-5 and by 15%/degrees C in those with a GCS 6-7. The increase in oxygen utilization was associated with an increase in plasma catecholamines. Sedatives, paralyzing agents, and propranolol all decreased RME. The cardiovascular response associated with increased oxygen utilization was an elevated cardiac output and, when RME was very high, a widened mean arterial-venous oxygen content difference, indicating that the tissues were more fully extracting oxygen. The increased cardiac output was dependent upon the presence of an adequate intravascular volume. During the 2-year period of study, a total of 99 patients with closed head injuries (including 44 patients who underwent studies) were admitted. The mortality rate of this consecutive series of comatose patients was 25%. The incidence of intracranial hypertension (30%) and of death from uncontrolled intracranial hypertension (12%) was not different from that reported in other recent series.(ABSTRACT TRUNCATED AT 250 WORDS)

The metabolic response to severe head injury

Caloric expenditure and nitrogen balance were measured in 14 steroid-treated comatose head-injured patients acutely and up to 28 days after injury. During this period patients were fed with a continuous enteral infusion of a formula containing 2 Kcal/cc and 10 gm nitrogen/liter. Indirect calorimetry was carried out for 102 patient-days. The mean resting metabolic expenditure (RME) for nonsedated nonparalyzed patients was 138% +/- 37% of that expected for an uninjured resting person of equivalent age, sex, and body surface area. Nitrogen excretion was measured for 135 patient-days. The mean excretion was 20.2 +/- 6.4 gm/day. The mean protein caloric contribution was 23.9% +/- 6.7% and was greater than 25% for six patients, compared to normal values of 10% to 15%. Despite hyperalimentation, positive nitrogen balance for any 3-day period was achieved in only seven patients, and required replacement of 161% to 240% of RME with enterally administered formula. Head-injured patients had a metabolic response similar to that reported for patients with burns of 20% to 40% of the body surface.

Aneurysmal bone cyst of the rib

Aneurysmal bone cysts are uncommon lesions, especially in the ribs. Four patients with aneurysmal bone cysts of the rib are presented and previously reported cases reviewed. A brief discussion of the clinical manifestations, pathology, aetiology, and current treatment of aneurysmal bone cyst is also included.

Cardiovascular response to severe head injury

The cardiovascular, pulmonary, and metabolic responses to severe head injury were studied clinically in the acute phase after severe head injury with the object of determining if a common response was present and, if so, its significance in the management of the patients' intracranial and systemic physiological states. Cardiac output, pulmonary capillary wedge pressure, arterial blood pressure, arterial and mixed venous blood gases, and arterial and mixed venous epinephrine (E) and norepinephrine (NE) levels were measured serially in 15 patients during the first 3 days after injury. A hyperdynamic state was found, characterized by increased cardiac output, cardiac work, moderate hypertension, tachycardia, decreased or normal systemic and pulmonary vascular resistance, increased pulmonary shunting, and increased oxygen delivery and utilization. Arterial E and NE levels correlated well with the cardiac output, cardiac work, blood pressure, heart rate, oxygen delivery, and oxygen utilization but not with vascular resistance or pulmonary shunt. The magnitude of the hyperdynamic state did not correlate with intracranial pressure, Glasgow Coma Scale score, or computerized tomography findings. It is concluded that a hyperdynamic cardiovascular state occurs after severe head injury, and that it is mediated in part by sympathetic nervous activity. The significance of this state for systemic management of patients with head injury is discussed.

Treatment of hypertension associated with head injury

Arterial hypertension that occurs after severe head injury is characterized by elevation of systolic blood pressure, tachycardia, increased cardiac output, normal or decreased peripheral vascular resistance, and increased circulating catecholamines. The effects of two drugs used in the management of hypertension, propranolol and hydralazine, on these indices of cardiovascular function were examined in six head-injured patients. Both drugs effectively normalized blood pressure. However, hydralazine increased heart rate by 30%, cardiac index by 49%, left cardiac work by 21%, and pulmonary venous admixture by 53%, and was responsible for an increase in intracranial pressure or decreased compliance in two patients. Hydralazine produced no consistent change in arterial catecholamines. In contrast, propranolol decreased heart rate by 21%, cardiac index by 26%, left cardiac work by 35%, pulmonary venous admixture by 15%, and oxygen consumption by 18%. Propranolol decreased arterial epinephrine levels by 48% and norepinephrine levels by 28%. Propranolol appears to be a useful antihypertensive drug in the hyperdynamic head-injured patient because it normalizes blood pressure and the underlying hemodynamic abnormalities both by its beta-adrenergic blocking action and by decreasing circulating levels of catecholamines.

Failure of histidine supplementation to improve anemia in chronic dialysis patients

Failure of histidien supplementation to improve anemia in chronic dialysis patients was seen in six patients after a study period of 8 weeks. Serum amino acid levels were elevated to normal by supplementation with 1 g of oral histidine/day in all patients. There was no significant change in serum iron or transferrin levels, hematocrit, or red cell mass in five of the six patients. Histidine supplementation may raise serum amino acid levels, but does not cause any increase in red cell mass or improve the anemia in patients on chronic dialysis who are ingesting adequate dietary protein.

A radiological study of morphology and growth in the human fetal colon

A radiological study has been made of the colon in 64 human fetuses between 11 and 20 weeks gestation (64-160 mm crown rump (CR) length). A dynamic picture of colon development was obtained from analysis of the radiographs. The findings challenge textbook descriptions, but can be interpreted in terms of the ultimate morphology of the colon. According to the morphology of the proximal (pre-splenic) part of the colon, there are three types of colon. In Type 1 it lies transversely, in Type 2 it is oblique in direction, and Type 3 has a postnatal form with ascending and transverse elements. Although the Type 1 predominates in smaller fetuses and the type 3 is most common in larger fetuses, there is some overlap in their distribution. The ileocaecal junction does not descend, but actually slightly ascends as the fetus grows. The splenic flexure grows in a distinctly cranial direction, and at almost three times the rate of the ileocaecal junction. Thus, as the fetus develops, the ileocaecal junction and splenic flexure grow further apart, and this determines the change from a Type 1 to a Type 2 colon. The divergence of the ileocaecal junction and splenic flexure appears to be related to different rates of growth in the colon, the distal (post-splenic) part growing almost half as fast again as the proximal (pre-splenic) part. The more mature (Type 3) form of colon appears to result from conversion of the Type 2 following early adhesion between the proximal colon and the second part of the duodenum.

Magnetic Bays at Macquarie Island

Polar magnetic bays are the most striking feature of magnetic records obtained by the Australian National Antarctic Research Expeditions at Macquarie Island. Negative bays are more numerous than positive bays and have greater amplitudes and durations. As a rule, negative bays commence about magnetic midnight whereas positive bays commence about 5 hr earlier. A daily reversal in direction of the bayproducing currents is indicated and the time at which this reversal takes place appears to vary with the seasons. During magnetically disturbed periods the ratio H bay amplitude to Z bay amplitude increases, indicating a northward movement of the bay-producing currents. At the same time auroras seen from Macquarie Island lie further north in the sky than usual.