Epidemiology of pneumonia in a burn care unit: the influence of inhalation trauma on pneumonia and of pneumonia on burn mortality.

The aim of this study is to determine the epidemiological characteristics of burn patients developing pneumonia, as well as the predisposing factors and the mortality of these patients. Infectious complications present serious problems in severely burned patients. Pneumonia, in particular, is a major cause of morbidity and mortality in burn patients. Patients with inhalation injuries are exposed to a greater risk due to the possible development of infectious complications in the lower respiratory tract. During their stay in our Burn Care Unit, 22.9% of our burn patients developed pneumonia and 10.9 % of these patients died. Risk factors for the development of pneumonia in burn patients were found to be inhalation trauma, high ABSI score, the Baux and modified Baux index, and high ASA score (p<0.01). Age and gender showed no significant correlation to the incidence of pneumonia. In this study we were able to determine the incidence of pneumonia in burn patients, their mortality and the strong correlation of the presence of inhalation injury with the development of pneumonia.

Le but de cette étude est de déterminer les caractéristiques épidémiologiques des patients brûlés qui développent une atteinte pulmonaire , ainsi que les facteurs prédisposants et le taux de mortalité . La pneumonie est une cause majeure de morbidité et de mortalité chez les patients gravement brûlés. Les patients atteints de lésions par inhalation sont exposés à un risque plus élevé en raison de l'évolution possible de complications infectieuses dans les voies respiratoires inférieures. Au cours de leur séjour dans notre unité de soins aux brûlures, 22,9% de nos patients brûlés ont développé la pneumonie et 10,9% de ces patients sont décédés. Les facteurs de risque pour le développement de la pneumonie chez les patients brûlés retrouvés sont le traumatisme de l'inhalation, le score élevé de ABSI, l'incice de Baux et l'indice Baux modifié, et le score ASA élevé (p <0,01). L'âge et le sexe des patients n'ont montré aucune corrélation significative à l'incidence de la pneumonie. Dans cette étude, nous avons pu déterminer l'incidence des complications pulmonaires du fait des lésions par inhalation .chez les patients brûlés, ainsi que sur le taux de mortalité.

Management of difficult intra-articular fractures or fracture dislocations of the proximal interphalangeal joint.

Intra-articular fractures or fracture dislocations of the proximal interphalangeal joint are difficult clinically because the bone and soft tissue structures are small and intricate. Suboptimal treatment of intra-articular fractures typically leads to functional impairment of the hand. This article reviews the current methods of treatment, together with the senior author's experience in treating difficult proximal interphalangeal joint fractures and dislocations. Besides conservative treatments, surgical treatments include open or closed reduction with traditional Osteosynthesis, such as K-wires, screws or plates. Among recent developments are the percutaneous application of thin cannulated compression screws and novel dynamic external fixators. After a preferred minimally invasive treatment with stable reconstruction of the articular surface, sufficient aftercare is necessary to improve surgical outcomes.

Bioartificial skin.

The loss of skin has been one of the oldest, yet most frequent and costly problems in our health care system. To restore functional and esthetic integrity in patients with unstable or hypertrophic scars, in burn patients and after skin loss for hereditary, traumatic or oncological reasons, an armamentarium of reconstructive surgical procedures including autogenous, allogenous and xenogenous tissue transfer as well as implantation of alloplastic materials has been favored. For several decades there has been increasing interest focused on 'tissue engineering' of dermal, epidermal and full thickness skin substitutes by both biological and synthetic matrices. At our institution (Hannover Medical School), a collagen/glycosaminoglycan dermal regeneration matrix has been used for immediate dermal coverage after escharectomy in burn injuries as well as for dermal replacement in chronically unstable scars. This article gives an overview on the current state of the art in bioartificial skin as well as our personal experience with the collagen/glycosaminoglycan matrix for dermal replacement in different clinical situations.

Persistence of pedicle blood flow up to 10 years after free musculocutaneous tissue transfer.

The hypothesis of whether or not flap perfusion remains persistent through its vascular pedicle up to 10 years after free tissue transfer was tested. Since 1982, more than 1,000 free tissue transfers have been performed at this institution. Of these, 40 patients were selected with comparable posttraumatic soft-tissue defects of the lower leg and surgical repair by a latissimus dorsi myocutaneous free flap. All patients had a postoperative course free of complications. Measurements of flap perfusion were started in groups 1 through 4 (each 10 patients) 3 to 5 weeks, 5 to 7 months, 4 to 6 years, and 8 to 10 years after free tissue transfer, respectively. Quantitative measurements of local flap perfusion were performed by means of the hydrogen clearance technique (Ameda, Switzerland) at definite sites intracutaneously and subcutaneously within the flap's skin paddle as well as in the adjacent intracutaneous and subcutaneous skin of the surrounding soft tissue. Simultaneously, the vascular pedicle of the flap was visualized by a duplex scanner (Toshiba, Japan). In each group nine measurements were performed before (phase A), during (phase B), and after closing the pedicle (phase C) by manual compression. Each measurement took about 10 minutes. Statistical evaluation of the obtained values was achieved by the Mann-Whitney U test and the Wilcoxon signed rank test. Local flap perfusion showed no statistical differences for phase A and C in all four groups of patients. In phase B, however, a statistically highly significant (p < 0.01) absence of local flap perfusion was registered in all four groups at the site of the flap's skin paddle. No statistically significant alterations of intracutaneous and subcutaneous blood flow was found in the surrounding soft tissue. In our clinical-experimental setting, flap perfusion persisted by means of its vascular pedicle even 10 years after free tissue transfer. Our findings support the importance of an intact vascular pedicle for permanent flap survival after free tissue transfer.

Postoperative blood flow monitoring after free-tissue transfer by means of the hydrogen clearance technique.

The hydrogen clearance technique was introduced for monitoring postoperative blood flow after free-tissue transfer in this prospective clinical study. This technique allows unlimited repeatable quantitative measurements of tissue blood flow in milliliters per minute per 100 gm of tissue at any site including buried flaps. In this study a real-time blood flow measuring system (Ameflow, Ameda, Switzerland) was employed. Two thousand eight hundred and twenty-three blood flow measurements were carried out on 72 free-tissue transfers, which were performed on 71 patients. Nine of these 72 flaps showed vascular complications (12.5 percent), including arterial thrombosis in 6.9 percent (n = 5), hematoma in 4.2 percent (n = 3), and venous thrombosis in 1.4 percent (n = 1). Complications as well as uneventful postoperative cases were monitored correctly by the hydrogen clearance technique in all cases, reaching sensitivity and specificity values of 1.0 for this technique in our study. Furthermore, all complications could be detected earlier by the hydrogen clearance technique than by clinical monitoring alone, which allowed flap salvation in 7 of 9 cases and a resulting permanent failure rate of free-tissue transfer of 2.8 percent (n = 2). From our data we conclude that the hydrogen clearance technique is a promising tool for postoperative blood flow monitoring after free-tissue transfer. For experimental pathophysiologic and pharmacologic studies of tissue blood flow in flaps, further evaluation of our measuring device including comparative studies with other established techniques is highly recommended.

Technetium-99m human immunoglobulin (HIG): a new substance for scintigraphic detection of bone and joint infections.

Technetium (99m-Tc)-labelled, polyclonal human immunoglobulin (HIG) has been described as a new agent to detect local infection and inflammation. In this study, we tested 99m-Tc HIG in 55 patients with suspected chronic (n = 42) and acute (n = 13) skeletal infection. Diagnosis was proven operatively (n = 44) and clinically (n = 11), including microbiological culture tests (n = 46). A gamma camera scan was performed 4 and 24 hours after I.v. injection of 500 MBq 99m-Tc-HIG. 99m-Tc-HIG scanning achieved a sensitivity of 91% and a specificity of 93%. We found one false negative and five false positive scintigraphic results in 55 patients. No clinical or biochemical side effects were encountered after 99m-Tc-HIG injection. We recommend this technique especially for localisation of low-grade, chronic osteomyelitis. The mechanisms and kinetics of 99m-Tc-HIG, however, are worth investigating more extensively.

Approaches to postoperative blood flow monitoring after free tissue transfer. Which is the best?

Success rates for free tissue transfer (FTT) have greatly improved over the last 20 years, partly due to improved technical performance of microvascular anastomoses with better optical and instrumental aids. However, flap failure is still a clinical problem and occurs in 5-10%, mainly due to blood vessel thrombosis within the first 24 postoperative hours. Salvation rates of failing FTT can be optimized by the prompt diagnosis of irreversibly compromised tissue blood flow and immediate operative reexploration. Therefore, there is a special demand for adequate and reliable postoperative monitoring techniques. This article gives an overview of all monitoring techniques, which have been performed both in the experimental and clinical setting after FTT thus far.

Measurements of tissue blood flow by the hydrogen clearance technique (HCT): a comparative study including laser Doppler flowmetry (LDF) and the Erlangen micro-lightguide spectrophotometer (EMPHO).

The purpose of this study was to compare the hydrogen clearance technique (HCT) with two different, well-established techniques, i.e., the laser Doppler flowmetry (LDF) and the Erlangen micro-lightguide spectrophotometer (EMPHO), for tissue blood flow measurements in an experimental setting. For the animal experiments, we chose a rat model for arterial and venous flap thrombosis, using the epigastric groin flap. Forty male dark Aguty rats were included in the study. The animals were divided into eight groups, each with a different vascular thrombotic model. HCT was used to collect 1,467 measurements, and 2,934 graphs were recorded; 27 measurements (54 graphs) had to be discarded due to faulty electrode placements and electronic noise. In 19 of the 27 discarded measurements the cause of failure was moving of the awaking animal with disruption of the decay signal. The LDF and EMPHO measurements were performed continuously during each measuring phase. Simple and multiple linear regression and paired t-tests were used to compare the three techniques. The reproducibility of registered blood flow values in phases 1, 3, 6 and 7 varied between 7.8% and 13.6% which is in about the same range as LDF and EMPHO. We could not find a significant difference between the three techniques in this regard. The correlation coefficient for HCT and LDF was r = 0.89. For HCT and EMPHO we found r = 0.67. Sensitivity and specificity values for HCT were both 1.0 in detecting arterial and venous flap thrombosis; for LDF we found values of 0.89 and 0.92, respectively. Sensitivity and specificity values for EMPHO were 0.92 and 0.95, respectively. After careful evaluation of three different techniques (HCT, LDF, and EMPHO) for measurements of local tissue blood flow we came to the conclusion that HCT must be favoured as a reliable tool for quantitative measurement of local tissue blood flow and early diagnosis of arterial and venous flap thrombosis.

Techniques of postoperative blood flow monitoring after free tissue transfer: an overview.

Ever since free tissue transfer has been established in microsurgery, success rates have greatly improved over the years, partly due to improved technical performance of microvascular anastomoses with better optical and instrumental aids. However, flap failure still occurs in 5-10%, mainly due to blood vessel thrombosis within the first 24 postoperative hours. Salvation rates of failing free tissue transfers can be optimized by in-time diagnosis of irreversibly compromised tissue blood flow and immediate operative reexploration. Therefore, there is a special demand for adequate and reliable postoperative monitoring techniques. This article gives an overview of all monitoring techniques, which have been performed both in the experimental and clinical setting thus far.

Routine monitoring in patients with free tissue transfer by laser-Doppler flowmetry.

The use of laser Doppler flowmetry (LDF) was tested in 108 consecutive patients, who underwent free tissue transfer at our institution between December, 1988, and June, 1990. Sixteen patients (14.8%) suffered vascular complications, which could be detected in all cases earlier by LDF than by clinical examination alone. LDF therefore prompted faster surgical intervention in these cases, allowing flap salvation in 9.3% (n = 10). Difficulties had to be noted in diagnosing venous thrombosis by means of the LDF due to sometimes unspecific alterations in LDF signals. Technical improvement of LDF might lead to a higher diagnostic accuracy if venous thrombosis occurs.