Fish oil after abdominal aorta aneurysm surgery

OBJECTIVE

Fish oil (FO) may attenuate the inflammatory response after major surgery such as abdominal aortic aneurysm (AAA) surgery. We aimed at evaluating the clinical impact and safety aspects of a FO containing parenteral nutrition (PN) after AAA surgery.

METHODS

Intervention consisted in 4 days of either standard (STD: Lipofundin medium-chain triglyceride (MCT): long-chain triglyceride (LCT)50%-MCT50%) or FO containing PN (FO: Lipoplus: LCT40%-MCT50%-FO10%). Energy target were set at 1.3 times the preoperative resting energy expenditure by indirect calorimetry. Blood sampling on days 0, 2, 3 and 4. Glucose turnover by the (2)H(2)-glucose method. Muscle microdialysis.

CLINICAL DATA

maximal daily T degrees, intensive care unit (ICU) and hospital stay.

RESULTS

Both solutions were clinically well tolerated, without any differences in laboratory safety parameters, inflammatory, metabolic data, or in organ failures. Plasma tocopherol increased similarly; with FO, docosahexaenoic and eicosapentaenoic acid increased significantly by day 4 versus baseline or STD. To increased postoperatively, with a trend to lower values in FO group (P=0.09). After FO, a trend toward shorter ICU stay (1.6+/-0.4 versus 2.3+/-0.4), and hospital stay (9.9+/-2.4 versus 11.3+/-2.7 days: P=0.19) was observed.

CONCLUSIONS

Both lipid emulsions were well tolerated. FO-PN enhanced the plasma n-3 polyunsaturated fatty acid content, and was associated with trends to lower body temperature and shorter length of stay.

[Nutrition and stress]

Acute illness induces major physiological responses, which favor the adaptation of the organism to stress and injury. The metabolic response plays key roles in maintenance of vital functions and promotion of the healing mechanisms. All the components of energy expenditure are modified, particularly the resting metabolism. The regulation of carbohydrate metabolism is also markedly altered. Such patients are characterized by fasting and postprandial hyperglycemia, insulin resistance, and by a stimulation of the hepatic glucose production in fasted and fed states. Lipolysis and increased fat oxidation are typically observed. Ketogenesis processes are inhibited, concurring to alter the adaptation to starvation. Protein turnover is stimulated with a preponderance of the catabolic processes, even during full nutritional support. This induces a state of resistance to feeding, leading to a progressive depletion of the fat free mass. Such progressive tissue catabolism cannot be reversed by hypercaloric nutrition or growth factors. Specific nutrients (aminoacids, micronutrients, PUFA) may offer interesting perspectives in stimulating immunity, improving the antioxidant balance or modulating the inflammatory response.

Trace element supplementation modulates pulmonary infection rates after major burns: a double-blind, placebo-controlled trial

Infections remain the leading cause of death after major burns. Trace elements are involved in immunity and burn patients suffer acute trace element depletion after injury. In a previous nonrandomized study, trace element supplementation was associated with increased leukocyte counts and shortened hospital stays. This randomized, placebo-controlled trial studied clinical and immune effects of trace element supplements. Twenty patients, aged 40 +/- 16 y (mean +/- SD), burned on 48 +/- 17% of their body surfaces, were studied for 30 d after injury. They consumed either standard trace element intakes plus supplements (40.4 micromol Cu, 2.9 micromol Se, and 406 micromol Zn; group TE) or standard trace element intakes plus placebo (20 micromol Cu, 0.4 micromol Se, and 100 micromol Zn; group C) for 8 d. Demographic data were similar for both groups. Mean plasma copper and zinc concentrations were below normal until days 20 and 15, respectively (NS). Plasma selenium remained normal for group TE but decreased for group C (P < 0.05 on days 1 and 5). Total leukocyte counts tended to be higher in group TE because of higher neutrophil counts. Proliferation to mitogens was depressed compared with healthy control subjects (NS). The number of infections per patient was significantly (P < 0.05) lower in group TE (1.9 +/- 0.9) than in group C (3.1 +/- 1.1) because of fewer pulmonary infections. Early trace element supplementation appears beneficial after major burns; it was associated with a significant decrease in the number of bronchopneumonia infections and with a shorter hospital stay when data were normalized for burn size.

Exudative mineral losses after serious burns: a clue to the alterations of magnesium and phosphate metabolism

Hypomagnesemia and hypophosphatemia are frequent after severe burns; however, increased urinary excretion does not sufficiently explain the magnitude of the mineral depletion. We measured the mineral content of cutaneous exudates during the first week after injury. Sixteen patients aged 34 +/- 9 y (mean +/- SD) with thermal burns were studied prospectively and divided in 3 groups according to the extent of their burn injury and the presence or absence of mineral supplements: group 1 (n = 5), burns covering 26 +/- 5% of body surface; group 2 (n = 6), burns covering 41 +/- 10%; and group 3 (n = 5), burns covering 42 +/- 6% with prescription of magnesium and phosphate supplements. Cutaneous exudates were extracted from the textiles (surgical drapes, dressings, sheets, etc) surrounding the patients from day 1 to day 7 after injury. Mean magnesium serum concentrations decreased below reference ranges in 12 patients between days 1 and 4 and normalized thereafter. Phosphate, normal on day 0, was low during the first week. Albumin concentrations, normal on day 0, decreased and remained low. Urinary magnesium and phosphate excretion were within reference ranges and not larger in group 3. Mean daily cutaneous losses were 16 mmol Mg/d and 11 mmol P/d (largest in group 2). Exudative magnesium losses were correlated with burn severity (r = 0.709, P = 0.003). Cutaneous magnesium losses were nearly four times larger than urinary losses whereas cutaneous phosphate losses were smaller than urinary phosphate losses. Mean daily losses of both magnesium and phosphate were more than the recommended dietary allowances. Exudative losses combined with urinary losses largely explained the increased mineral requirements after burn injury.

Sedatives and antagonists in the management of severely head-injured patients

Continuous intravenous sedation is often prescribed during the intensive treatment of severe head injury. It is known that intravenous hypnotics may prevent or treat the brief intracranial hypertension episodes associated with nociceptive stimuli, like tracheal intubation. However there is yet no clear evidence in the literature showing beneficial effects of sedation in severely head-injured patients on intracranial pressure control or outcome. Sedation should be primarily administered in neurotraumatology to allow good conditions for intensive treatment, while avoiding any depressive cardiovascular action. The abrupt reversal of sedation by means of specific antagonists may induce significant elevation of both cerebral blood flow and intracranial pressure and should be avoided.

[Energy metabolism and craniocerebral injury]

Severe head injury induces major hormonal, humoral and metabolic changes, characterized by increases in stress hormone secretion, lymphokines production, associated with high lipid and protein catabolism as well as changes in energy expenditure (EE). Numerous factors influence EE in head-injured patients, particularly anthropometric data, body temperature, nutritional support, level of consciousness, muscular tone and activity. Resting EE is usually increased following brain trauma; however, normal or decreased metabolic rates can be observed in curarized patients on mechanical ventilation or in patients receiving high doses of barbiturates.

[Principles of the use of indirect calorimetry in intensive care]

Energy expenditure measurements in critically ill patients using indirect calorimetry is complex and often very inaccurate. Analysis of the data should first question their validity. The components of energy expenditure should be carefully separated to assess the effects of illness, drugs and supportive treatments.

The effects of midazolam reversal by RO 15-1788 on cerebral perfusion pressure in patients with severe head injury

In patients with severe head injury, midazolam is a convenient agent for sedation during mechanical ventilation, although its sedative effect can be prolonged. We investigated the effects of acute midazolam reversal by RO 15-1788 (RO), a benzodiazepine antagonist, on intracranial pressure (ICP), cerebral perfusion pressure (CPP) and on recovery in 18 studies performed on 15 patients with severe head injury (Glasgow coma score less than 8). ICP increased significantly from 16.3 mmHg +/- 2 (mean +/- SEM) to 24.1 mmHg +/- 4.2 (p less than 0.02) and to 25.2 mmHg +/- 4 (p less than 0.01), 5 and 10 min respectively after RO administration. Analysis of the results showed 2 patterns of response in ICP. In patients with good control of ICP before RO administration, there was no change in ICP and CPP, whereas in patients with abnormal ICP, RO injection induced severe increase in ICP and concomitant decrease in CPP. Arousal after midazolam reversal was obvious in 5 patients who were quickly extubated. Midazolam reversal by RO should not be attempted in patients with severe head injury and unstable ICP.

[Use of flumazenil (RO 15-1788) after prolonged infusion of midazolam in anesthesia for intracranial surgery]

Midazolam, with a half-life of about 1.5-3.5 h, is inappropriate for the maintenance of anaesthesia during long procedures, especially when rapid recovery is necessary. The efficacy of flumazenil, a specific benzodiazepine antagonist, in the treatment of patients with benzodiazepine overdose suggests that rapid recovery from anaesthesia induced and maintained with midazolam might be obtained in patients needing immediate assessment. The rate of recovery, the side-effects and the feasibility of an early and accurate neurological assessment were studied in 18 ASA III patients after craniotomy in whom the prolonged effects of midazolam had been antagonized by flumazenil. Surgery lasted 5.5 +/- 1.3 h (means +/- SD). The induction dose of midazolam was 0.32 +/- 0.08 mg.kg-1 and the infusion rate was 0.2 +/- 0.08 mg.kg-1.h-1. Fentanyl was added at a dose and rate of 5.0 +/- 3.6 micrograms.kg-1 and 2.0 +/- 0.9 micrograms.kg-1.h-1 respectively. At the end of the dressing, 0.5 mg of flumazenil (t0) was injected, followed by 0.1 mg every minute up to a total of 1 mg. After 2 min, 14 patients (78%) opened their eyes (p less than 0.05) and 13 (72%) obeyed orders (p less than 0.05). After 10 min, 16 patients (89%) were extubated and speaking. During the first 10 min, the Glasgow score and the sedation score used for this study showed the same progression, with 13 patients (72%) having a Glasgow score of 14-15 (p less than 0.05). Thereafter, both scores decreased progressively till t60, then increased again, reaching their t10 level at t120. Three patients required another dose of antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)