Effects of regional anesthesia on phantom limb pain are mirrored in changes in cortical reorganization

The causes underlying phantom limb pain are still unknown. Recent studies on the consequences of nervous system damage in animals and humans reported substantial reorganization of primary somatosensory cortex subsequent to amputation, and one study showed that cortical reorganization is positively correlated with phantom limb pain. This paper examined the hypothesis of a functional relationship between cortical reorganization and phantom limb pain. Neuroelectric source imaging was used to determine changes in cortical reorganization in somatosensory cortex after anesthesia of an amputation stump produced by brachial plexus blockade in six phantom limb pain patients and four pain-free amputees. Three of six phantom limb subjects experienced a virtual elimination of current phantom pain attributable to anesthesia (mean change: 3.8 on an 11-point scale; Z = -1.83; p < 0.05) that was mirrored by a very rapid elimination of cortical reorganization in somatosensory cortex (change = 19.8 mm; t(2) = 5.60; p < 0.05). Cortical reorganization remained unchanged (mean change = 1.6 mm) in three phantom limb pain amputees whose pain was not reduced by brachial plexus blockade and in the phantom pain-free amputation controls. These findings suggest that cortical reorganization and phantom limb pain might have a causal relationship. Methods designed to alter cortical reorganization should be examined for their efficacy in the treatment of phantom limb pain.

[Prognostic scores in intensive care]

Since the development of prognostic score systems in intensive care medicine in the 1980s score models have improved substantially and are now based on much larger databases. They have been validated in many multicenter and international studies all over the world. Prognostic scoring systems may be used for assessment of severity of illness, stratifying patients prior to randomization in clinical trials, evaluation and comparing outcome and survival (hospital mortality), quality assessment, cost-benefit analysis, and in clinical decision making. Validated time points for predicting hospital mortality of ICU patients are at admission and at 24 hours. The relationship of the observed hospital mortality rate to the estimated mortality provides the basis for clinical performance measurement. Since each ICU serves a different patient population, each score system must be calibrated in the individual hospital to ensure that the model is applicable. General scores covering more than one disease are Acute Physiology And Chronic Health Evaluation (APACHE II, APACHE III), Simplified Acute Physiology Score (SAPS) and Mortality Predicting Model (MPM). The Therapeutic Intervention Scoring System (TISS) and in part the Hannover Intensive Score (HIS) evaluate exclusively the amount of medical therapy required. The TISS-Score might serve as a possible measure of resource use for the ICU portion of the hospital stay. Disease (e.g. Trauma Score, Injury of Severity Score) and patient (e.g. PRISM = Pediatric Risk of Mortality) specific scores take into account the influence of disease and patient population in relation to outcome. They are not always of more predictive value than general score models. Score models have been criticized for a number of reasons. Outcome of ICU therapy should incorporate not only survival but should also take into account quality of life, morbidity and disability. Severity scores have no role in clinical decision making for an individual patient (e.g. patient triage for ICU admission, discharge criteria, withdrawal of life support). This is due to the current low sensitivity. Subsequent validation of variables could improve the sensitivity and the value of severity scoring in the future. Nevertheless, illness severity scores will never be indicative of absolute irreversibility of disease or impossibility of survival. Advances in computer technology should assist in achieving many of the future goals of prognostic scoring systems. Most of the physiological data are available from ICU monitors and computerized laboratory systems. By electronically interfacing with the ICU monitor an automated patient data entry is possible and will provide that prognostic scores can be made available to the clinician daily.

The prevention of anastomotic leakage after total gastrectomy with local decontamination. A prospective, randomized, double-blind, placebo-controlled multicenter trial

OBJECTIVE

A prospective, randomized, double-blind, placebo controlled multicenter trial was undertaken in 205 patients treated with total gastrectomy for gastric malignancies to evaluate whether local antimicrobial measures reduce the incidence of esophagojejunal anastomotic leakage.

SUMMARY BACKGROUND DATA

Anastomotic leakage of the esophagojejunostomy is always a septic complication of total gastrectomy for gastric malignancies, but it never has been attempted to prevent this complication with the administration of topical antimicrobial agents during the critical phase of anastomotic wound healing.

METHODS

To evaluate the efficacy and safety of topical decontamination, the study was carried out as a prospective, randomized, double-blind and placebo-controlled clinical multicenter trial in patients with total gastrectomy for gastric cancer. Patients received either placebo or decontamination with polymyxin B (100 mg), tobramycin (80 mg), vancomycin (125 mg), and amphotericin B (500 mg) four times per day orally from the day before the operation until the seventh postoperative day. All patients received a perioperative intravenous prophylaxis with cefotaxime 2 x 2 g. Other interventions including the administration of antibiotics and fluids, were not affected by the study protocol.

RESULTS

Of 260 patients who were randomized, total gastrectomy was not carried out in 55 patients. They dropped out of the study. Patients receiving an esophagojejunostomy were observed until day 42, when they were discharged from the clinic or died. An intention-to-treat analysis of the data was carried out. Among the 103 recipients of placebo, there were 11 (10.6%) with an anastomotic leakage of the esophagojejunostomy, and among the 102 recipients of decontamination, there were 3 (2.9%) with an anastomotic leakage of the esophagojejunostomy (p = 0.0492). Pulmonary infections were observed in 23 patients (22.3%) receiving placebo and in 9 patients (8.8%) who were decontaminated (p = 0.02). There were 11 deaths (10.6%) among the recipients of placebo and 5 deaths (4.9%) among the recipients of decontamination (p = 0.1).

CONCLUSIONS

Decontamination with polymyxin, tobramycin, vancomycin, and amphotericin B during anastomotic wound healing is safe and effective in the prevention of esophagojejunal anastomotic leakage after total gastrectomy.

[Potentialities and limitations of the score system in intensive medicine]

In intensive-care medicine, score systems serve to quantify the severity of diseases and to characterise patient groups on the basis of objective criteria. The principle is to describe the severity by adding up points. Objectives are to assess the prognosis, to establish the amount of treatment required and assist in clinical decision making. The most important examples of general scores covering more than one disease are Acute Physiology And Chronic Health Evaluation (APACHE-II, APACHE-III), Simplified Acute Physiology Score (SAPS) and Mortality Prediction Model (MPM). General scores assess the deviation of physiological parameters from the normal assuming that the degree of deviation reflects the severity of the disease. The Therapeutic Intervention Scoring System (TISS) constitutes a particular form which evaluates exclusively the amount of therapy required. Disease-specific scores (trauma scores, sepsis scores) take into account the fact that the nature and stage of specific disease determine the outcome in a typical way. Scores are adequately validated and suitable for evaluation of clinical studies or cost-benefit analyses by characterisation of patient populations. The use of score systems for individual prognosis is at present controversial. Their clinical significance might increase in that scores help to make medical decisions by contributing to early identification of endangered patients by systematic establishment and evaluation of investigation results. Scores are likely to be used increasingly in intensive-care medicine.

Lung tissue concentrations of ciprofloxacin following intravenous administration in patients

Serum and corresponding lung tissue concentrations of ciprofloxacin (Ciprobay) were investigated in 25 patients undergoing open lung surgery for pulmonary malignancies. Drug levels were measured at various times (50-240 min) after completion of a single i.v. dose of 200 mg by bioassay and HPLC. Lung tissue concentrations peaked within one hour after dosing (bioassay: 3.2 micrograms/g, HPLC: 4.5 micrograms/g). Tissue levels exceeded corresponding serum level 3- to 4fold throughout the observation period. The results demonstrate excellent penetration properties of this new antimicrobial compound into lung tissue. Ciprofloxacin was concentrated in the lung and thus by far exceeded known minimum inhibitory concentrations for most nosocomial respiratory pathogens.

[The equilibrium of nitrogen, potassium and phosphate and renal excretion of creatinine and creatinine over the course of 3 weeks following severe trauma]

In 19 patients after accidental trauma and with intact renal function during an observation time of 21 days we found a cumulated negative balance of nitrogen (N), phosphate (P) and potassium (K) amounting to a mean of 214g, 357 and 447 mmol, respectively. Median daily potassium balance was positive on day 2 to 5 and this was interpreted as an increased extrarenal potassium deposition due to increased levels of circulating catecholamines. Median renal creatinine excretion was about 120% of predicted normal till day 10 and continuously decreased thereafter to values lower than predicted normal. Three patients did not show creatinuria (greater than 200 mg/day) during the whole observation time. In 15 patients after a "free interval" with a mean duration of 7 days creatinuria frequently developed rather quickly and maximal excretion of creatine was as high as 4 g/day. In 7 patients creatinuria persisted to the end of the 21 days observation time. During the phase of creatinuria the median cumulated excretion of creatine amounted to 14.4 g. The "free interval" of creatinuria after severe trauma is remarkable. Most of the N, K and P, which is lost from the body during this time obviously stems from tissues other than sceletal muscle. During the phase of creatinuria, however, the negative balance of N, K and P seems to be mainly due to muscle wasting. Hypophosphatemia was prominent during the first 5 days after trauma and obviously was caused by a decrease in renal phosphate threshold (TmPO4/GFR). The underlying mechanism of this primary change in renal function after severe trauma could not yet be identified.

Prevention of colonization and respiratory infections in long-term ventilated patients by local antimicrobial prophylaxis

In a randomized clinical trial the prophylactic effects of locally administered antimicrobials on quantitative colonization and respiratory infections were studied in intubated patients with an expected period of mechanical ventilation of greater than 6 days. Nineteen patients received 50 mg of polymyxin B and 80 mg of gentamicin distributed among nose, oropharynx and stomach at 6-h intervals, as well as 300 mg of amphotericin B in the oropharynx. Twenty untreated patients served as controls. In the control group colonization by respiratory pathogens was more common (oropharynx 19 vs 6 patients (p less than 0.001); trachea 19 vs 11 (p less than 0.01)), and the number as well as the count of the colonizing species was usually higher. Fourteen patients of the control group developed respiratory infections, including nine cases of pneumonia, as compared to four patients with prophylaxis, including one case of pneumonia (p less than 0.01). Pneumonia-associated deaths were prevented with prophylaxis; however, the overall mortality remained unchanged. Respiratory infections in the prophylaxis group were associated with organisms resistant to the agents used, but the overall occurrence of resistance was not increased, as compared to the control group. We conclude that unrestrained upper airway colonization by respiratory pathogens and respiratory tract infection were causally related. Local antimicrobial prophylaxis proved to be a highly effective strategy for the prevention of potentially life-threatening pneumonias in critically ill patients, but in the present study the host setting appeared to be the major determinant of outcome.

[Treatment of bronchopulmonary infections in patients during artificial respiration with imipenem/cilastatin]

In an open prospective study the efficacy and tolerance of imipenem/cilastatin was investigated in 24 critically ill patients on mechanical ventilation with nosocomial respiratory tract infection. Nine patients had previously received antibiotic therapy which had failed. Imipenem was given in a dose of 1-3g/24 h over 5-37 (mean 11) days. Seven patients were additionally treated with aminoglycosides, one patient with erythromycin. Pseudomonas aeruginosa, Staphylococcus aureus, Hemophilus influenzae and Escherichia coli were the most frequently isolated pathogens from tracheobronchial secretions. 91% of the infections without and 77% with involvement of Pseudomonas aeruginosa were successfully treated. All of the gram-positive and 85% of the gram-negative pathogens (Pseudomonas not included) were eliminated in the course of therapy. By contrast, 64% of the isolates of Pseudomonas aeruginosa persisted; half of these became imipenem-resistant. Nine patients showed adverse reactions including one case of pseudomembranous colitis which were reversible. Imipenem/cilastatin proved highly effective and was relatively well tolerated; limitations in the efficacy were seen in cases of infection due to Pseudomonas aeruginosa.

[Work of breathing in spontaneous respiration with continuous positive airway pressure]

In postoperative respiratory failure continuous positive airway pressure (CPAP), besides improving pulmonary gas exchange, influences respiratory mechanics. Elastic and flowresistive components of respiratory work were measured in intensive care patients being weaned from the respirator. Measured values during breathing with a continuous-flow CPAP system with elastic reservoir were compared with those for O2 breathing via T-tube. Under CPAP total breathing work and resistance were reduced. Compliance, tidal volume and respiratory frequency did not change significantly. The reduction in respiratory work was primarily due to decreased nonelastic work associated with a decrease in resistance. Thus, on weaning from mechanical ventilation using a reservoir-CPAP system, the respiratory work was reduced in comparison to O2 breathing via T-tube.

[Treatment of respiratory tract infections with imipenem/cilastatin in critical patients with respiratory insufficiency]

In an open prospective study the efficacy and tolerance of imipenem/cilastatin was investigated in 24 critically ill patients on mechanical ventilation with nosocomial respiratory tract infection. Nine patients had previously received antibiotic therapy, eight of them with various other beta-lactam antibiotics which had failed. Imipenem was given in a dose of 1-3 g/24 h over 5-37 (mean 11) days. Seven patients were additionally treated with aminoglycosides, one patient with erythromycin. Pseudomonas aeruginosa (n = 14), Staphylococcus aureus (n = 4), Haemophilus influenzae (n = 4) and Escherichia coli (n = 3) were the potential pathogens most frequently isolated from tracheo-bronchial secretions. All of the isolates were susceptible to imipenem. 91% of the infections without and 77% with involvement of P. aeruginosa were successfully treated. Two patients who had not responded to previous treatment succumbed to the consequences of progressive respiratory distress syndrome. All of the gram-positive and 85% of the gram-negative pathogens (Pseudomonas not included) were eliminated in the course of therapy. By contrast, 64% of the isolates of P. aeruginosa persisted; half of these became imipenem-resistant. Nine patients showed adverse reactions including one case of pseudomembranous colitis or laboratory abnormalities which were all reversible. Imipenem/cilastatin proved highly effective and was relatively well tolerated; it is suitable as a single agent for the initial treatment of nosocomial respiratory tract infections in ventilated patients, although only with limitations in cases of infection due to P. aeruginosa.

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH)--treatment with lithium

Two patients with SIADH after brain trauma are described. Features of SIADH are "inappropriate" antidiuresis and excessive natriuresis with negative sodium balance resulting in hyponatremia and plasma hypoosmolality which may lead to cerebral dysfunction. Oral lithium carbonate was beneficial in both patients. With plasma levels of lithium around 1 mmol/l a temporary impairment of renal concentrating ability and antinatriuresis with normalization of plasma sodium and plasma osmolality was observed. The SIADH subsided about 4 months after the original trauma, long after gross neurological symptoms had resolved.

[Pancreas grafts. Nuclear medical perfusion to exclude vascular complications and rejection crises (author's transl)]

Perfusion studies with 99m Tc-DTPA, which has hitherto been used routinely to investigate renal grafts, have also proved useful for monitoring the perfusion of pancreas grafts. A total perfusion failure is equally reliably demonstrable as in renal grafts. Quantitatively smaller perfusion alterations can be demonstrated by monitoring the course. It seems possible to differentiate the salivary edema of a rejection reaction, well known from animal experiments, with the help of other parameters (e. g. creatinine). Further clinical studies are however necessary to confirm these results.