Perioperative thermal insulation: minimal clinically important differences?

BACKGROUND

Reduction of heat losses from the skin by thermal insulation is used to avoid perioperative hypothermia. However, there is little information about the physical properties of various insulating materials used in the operating room.

METHODS

The following insulation materials were tested using a validated manikin: cotton surgical drape tested in two and four layers; Allegiance drape; 3M Steri-Drape; metallized plastic sheet; Thermadrape Barkey thermcare 1 tested in one and two layers; hospital duvet tested in one and two layers. Heat loss from the surface of the manikin can be described as: Q(*);= h.DeltaT.A where Q(*); is heat flux, h is the heat exchange coefficient, DeltaT is the temperature gradient between the environment and surface and A is the area covered. The heat flux per unit area (Q(*); A(-1)) and surface temperature were measured with nine calibrated heat-flux transducers. The environmental temperature was measured using a thermoanemometer. DeltaT was varied and h was determined by linear regression analysis as the slope of DeltaT vs Qdot; A(-1). The reciprocal of h defines the insulation.

RESULTS

The insulation value of air was 0.61 Clo. The insulation values of the materials varied between 0.17 Clo (two layers of cotton surgical drapes) to 2.79 Clo (two layers of hospital duvet).

CONCLUSIONS

There are relevant differences between various insulating materials. The best commercially available material designed for use in the operating room (Barkey thermcare 1) can reduce heat loss from the covered area by 45% when used in two layers. Given the range of insulating materials available for outdoor activities, significant improvement in insulation of patients in the operating room is both possible and desirable.

Erwärmungseffektivität und Erythrozytentraumatisierung verschiedener Infusions- und Bluterwärmungssysteme

QUESTION

Inadequately warmed blood or infusions contribute to the development of perioperative hypothermia. Therefore we analysed the efficiency of several infusion warmers.

METHOD

Tested infusion warmers: Model Autoline (Barkey) 500OR/241(Arizant), BW 385L(Biotest), H250/D50 und D60 (Level-1), H500/D300 (Level-1), Warmflo FW537-I/HEC40 (Tyco). Different solutions (saline, colloid solution and packed red blood cells PRBC) were tested varying the infusion flow, temperature of the solution and infusion pressure. Effective warming was defined as an infusion temperature > or = 33 degrees C. Haemolysis was measured by the increase of free plasma haemoglobin.

RESULTS

The infusion warmers were effective within the following flow ranges: Low flow rate (< 250 ml/h): Autoline, 500OR/241 and H250/D60. Medium flow rate (250-2500 ml/h): Autoline, 500OR/241, BW385L (> 480 ml/h), H250/D 60 und D50 (> or = 1300 ml/h), FW537-I/HEC40 (> 950 ml/h. High flow rate (2500-10,000 ml/h): BW385L (up to 5000 ml/h), H250/D50, H250/D60, H500/D300 and FW537-I/HEC 40(R). Highest flow rates (> 10,000 ml/h): H250/D60, H500/D300 and FW537-I HEC40. Colloidal solutions were warmed nearly as good as saline, cooled PRBC had a smaller range of effective warming. There was no relevant haemolysis in any of the tested systems (plasma free haemoglobin raise < 24 mg/dl in all systems).

CONCLUSION

The warming capacity of the system and the length of the uninsulated infusion system determine the efficiency of an infusion warmer. The range of effective warming of an infusion warmer should be known for proper application.

Clinical, haematological, immunohistochemical and pathological findings in 10 cattle with cutaneous lymphoma

This paper describes the clinical, haematological, immunohistochemical and pathological findings in 10 female cattle with cutaneous lymphoma. The most striking clinical finding was multifocal intracutaneous nodules, which were firm, hairless and sometimes covered with haemorrhagic crusts. All the animals had multiple lymphadenopathy. Eight of the animals had leucocytosis and two also had lymphocytosis. In seven animals, a definitive diagnosis of lymphosarcoma was made on the basis of biopsies of intracutaneous nodules or fine needle aspirates of superficial lymph nodes. In some of the cattle the kidneys, heart, spleen and lungs were affected.

[Case report: tenesmus in a cow with a liver abscess and nephritis]

A two-year-old Swiss Braunvieh cow was referred to our clinic because of tenesmus and weight loss. Clinical examination revealed a moderately abnormal general behaviour and condition, thin body condition and a rectal temperature of 40.1 degrees C. Tenesmus was evident, and rumen and intestinal motility were markedly reduced. All tests for a reticular foreign body were positive. On rectal examination, a round, smooth, firm, non-painful mass with a diameter of approximately 15 cm was palpated far cranially on the right side. Abnormal haematological and biochemical findings included marked anaemia, neutrophilic leucocytosis, markedly elevated concentration of fibrinogen and mildly elevated gamma-glutamyl-transferase activity. The clotting time of the glutaraldehyde test was one minute. Ultrasonographic examination revealed abscesses involving the liver and extending caudally into the right flank region. The liver parenchyma had diffuse changes. Because of a grave prognosis, the cow was euthanized. Postmortem findings substantiated ultrasonographic results; there were abscesses, caused by Fasciola hepatica infestation, originating in the liver and extending into the right flank. As well, there was severe, bilateral, multifocal, suppurative nephritis due to thromboembolism. Based on all the findings, a diagnosis of liver abscess caused by fascioliasis and bilateral suppurative nephritis was made.

Hauben- und Labmagenfremdkörper bei einer Kuh – Diagnostik und Therapie

Gegenstand und Ziel: Darstellung der Diagnostik und chirurgischen Behandlung von Labmagenfremdkörpern bei einer Kuh. Material und Methode: Bei einer fünfjährigen Holstein- Friesian-Kuh, die klinisch an einer Reticuloperitonitis traumatica erkrankt war, wurden röntgenologisch Fremdkörper sowohl in der Haube als auch im Labmagen festgestellt. Ergebnisse: Alle Fremdkörper konnten bei der Laparorumenotomie manuell entfernt werden, diejenigen im Labmagen über die Hauben-Psalter-Labmagen-Rinne. Die Kuh erholte sich gut und war bei einer Nachfrage fünf Monate postoperativ gesund und produktiv. Schlussfolgerungen: Fremdkörper, die im Labmagen liegen, können röntgenologisch dargestellt und über eine Rumenotomie extrahiert werden. Klinische Relevanz: Der Labmagen lässt sich über die Hauben- Psalter-Öffnung explorieren.

[Cardiomyopathy, endocarditis valvularis thromboticans and pericarditis traumatica in cows--clinical and echocardiographical findings in three cases]

The clinical, echocardiographical and pathomorphological findings of cows with either cardiomyopathy, endocarditis valvularis thromboticans and pericarditis traumatica are described. Based on these examples the use of echocardiography for improved diagnosis is presented.

Erhebungen zur Fettsäurenzusammensetzung von Rückenfett bei Thüringer Schweinen sowie zum Fett von Thüringer Knackwürsten aus dem Einzelhandel

Abstract. Title of the paper: Examinations to the fatty acid composition of backfat at Thuringian pigs as well as to the fat of Thuringian cracking sausages from the retail trade The fat from the outer back bacon of Thuringian pigs (n = 751) was examined several years with regard to their fatty acid composition. The content of polyunsaturated fatty acids (PUFA) ranged at the backfat from 7.3 to 12.7% and the relationship of the n-6 and n-3 fatty acids varied from 4.4 to 11.3. PUFA contents in the backfat > 12 % were explained by high C18:2 or C18:3 contents of the food. Examination of the fatty acid composition of the fat of 21 fresh cracking sausages from the Thuringian retail trade on a random basis yielded, that the contents of PUFA and linolenic acid ranged from 6.2 to 15.8 % respectively from 0.8 to 2.0 % as well as the quotient of n-6 to n-3 fatty acids varied from 3.6 to 10.3.

Differences among forced-air warming systems with upper body blankets are small. A randomized trial for heat transfer in volunteers

BACKGROUND

Forced-air warming is known as an effective procedure in prevention and treatment of perioperative hypothermia. Significant differences have been described between forced-air warming systems in combination with full body blankets. We investigated four forced-air warming systems in combination with upper body blankets for existing differences in heat transfer.

METHODS

After approval of the local Ethics Committee and written informed consent, four forced-air warming systems combined with upper body blankets were investigated in a randomized cross-over trial on six healthy volunteers: (1) BairHugger trade mark 505 and Upper Body Blanket 520, Augustine Medical; (2) ThermaCare trade mark TC 3003, Gaymar trade mark and Optisan trade mark Upper Body Blanket, Brinkhaus; (3) WarmAir trade mark 134 and FilteredFlow trade mark Upper Body Blanket, CSZ; and (4) WarmTouch trade mark 5800 and CareDrape trade mark Upper Body Blanket, Mallinckrodt. Heat transfer from the blanket to the body surface was measured with 11 calibrated heat flux transducers (HFTs) with integrated thermistors on the upper body. Additionally, the blanket temperature was measured 1 cm above the HFT. After a preparation time of 60 min measurements were started for 20 min. Mean values were calculated over 20 min. The t-test for matched pairs with Bonferroni-Holm-correcture for multiple testing was used for statistical evaluation at a P-level of 0.05. The values are presented as mean+/-SD.

RESULTS

The WarmTouch trade mark blower with the CareDrape trade mark blanket obtained the best heat flux (17.0+/-3.5 W). The BairHugger trade mark system gave the lowest heat transfer (8.1+/-1.1 W). The heat transfer of the ThermaCare trade mark system and WarmAir trade mark systems were intermediate with 14.3+/-2.1 W and 11.3+/-1.0 W.

CONCLUSIONS

Based on an estimated heat loss from the covered area of 38 W the heat balance is changed by 46.1 W to 55 W by forced-air warming systems with upper body blankets. Although the differences in heat transfer are significant, the clinical relevance of this difference is small.

Ultrasonography in gastrointestinal disease in cattle

Ultrasonography is an ideal diagnostic tool for investigating gastrointestinal disorders in cattle. It is performed on standing non-sedated cattle using a 3.5 MHz linear transducer. In animals with traumatic reticuloperitonitis, inflammatory fibrinous changes, and abscesses can be imaged; however, magnets and foreign bodies are difficult to visualize because of the gas content of the reticulum. Ultrasonography can be used to assess the size, position and contents of the abomasum. Percutaneous ultrasound-guided abomasocentesis can be performed to evaluate the nature and chemical composition of its contents. In left displacement of the abomasum, the abomasum is seen between the left abdominal wall and the rumen. It contains fluid ingesta ventrally and a gas cap of varying size dorsally. Occasionally, the abomasal folds are seen in the ingesta. In cattle with right displacement of the abomasum, the liver is displaced medially from the right abdominal wall by the abomasum, which has an ultrasonographic appearance similar to that described for left displacement. Motility and diameter of the intestine are the most important criteria for ultrasonographic assessment of ileus. However, the cause of the ileus is rarely determined using ultrasonography. In cases with ileus of the small intestine, there is at least one region of dilatation of the intestine and motility is reduced or absent. In cattle with caecal dilatation, the caecum can always be imaged from the right lateral abdominal wall. The wall of the caecum closest to the transducer appears as a thick, echogenic, semi-circular line.

[Radiographic findings in 4 cows with traumatic reticuloperitonitis caused by a nonmagnetic copper wire]

The goal of this study was to describe the findings in four cows with non-magnetic reticular foreign bodies composed of copper. The cows were referred to our clinic because of reduced appetite and a marked decrease in milk production. Based on the clinical findings, a tentative diagnosis of traumatic reticuloperitonitis was made in all cows. The reticulum of all cows was then examined ultrasonographically and radiographically. In all cows, radiographs of the reticulum showed wire-shaped foreign bodies, ranging from 3 to 7 cm in length, which appeared to have penetrated the reticular wall. Two cows (No. 3, 4) had a magnet in the reticulum close to the foreign body but there was no direct contact between the two. A magnet was administered to cows No. 1 and 2, and radiography of the reticulum was performed for a second time the following day. The magnets were observed in the reticulum; however, they did not contact the foreign bodies. Because all the magnets were correctly placed in the reticulum yet, despite close proximity, did not contact the foreign bodies, the latter were thought to be non-magnetic. Cow No. 1 was slaughtered. Left flank laparoruminotomy was performed in the remaining three cows. In all cows, copper foreign bodies ranging in length from 3.0 to 7.0 cm, were found in the reticulum. They had penetrated the reticular wall and were not attached to magnets. The radiographic findings described in the present study are strongly indicative of a non-magnetic foreign body. Ruminotomy is the treatment of choice but slaughter may also be considered.

[Prevalence of Fasciola hepatica and Dicrocoelium dendriticum in the cow: inspection in an east Switzerland abattoir]

On the basis of meat inspection in an abattoir in the eastern part of Switzerland, the incidence of liverflukes in cattle was recorded weekly during one year. The prevalence was compared with surveys from the seventies and nineties. The average incidence of Dicrocoelium dendriticum infection did not change. Although the prevalence of Fasciola hepatica apparently slightly decreased, an actual decrease of liverflukes could not be demonstrated.

[Clinical findings in four cattle with abscesses in the cervical vertebrae]

The purpose of this paper was to describe the clinical findings in four cattle with abscesses in the cervical vertebrae. In all of the animals there was generalized ataxia and normal behaviour, mentation and cranial nerve function. All animals had marked difficulty rising and had generalized ataxia. The most important haematological and biochemical findings were a mildly increased concentration of plasma protein in all animals and a markedly increased fibrinogen concentration in two animals. A sample of cerebrospinal fluid (CSF) was collected from three animals. The protein content was mildly increased in the CSF samples of two animals. Based on the clinical findings, a tentative diagnosis of central nervous system disease with localisation in the neck region was made in all of the animals. Due to a poor prognosis, all of the animals were slaughtered. Postmortem examination revealed abscesses in the region of C3 to C6, which had resulted in extramedullary compression of the spinal cord. The abscesses varied in diameter from 2 to 8 cm.

Effects of atropine, scopolamine and xylazine on the placement of an orally administered magnet in cows

This study was carried out to determine whether the administration of atropine, scopolamine or xylazine to cows before the administration of a magnet orally would help to position it in the reticulum. The transit time of the magnet through the oesophagus was also measured. Sixty Swiss Braunvieh cows were examined by radiography and ultrasonography to locate the reticulum. They were then divided into six groups of 10. Before the administration of the magnet, a control group received 4 ml saline solution subcutaneously, one group received 0.10 mg/kg of atropine subcutaneously, a second received 0.05 mg/kg of atropine intravenously, a third received 0.15 mg/kg of scopolamine intravenously, a fourth group received 0.02 mg/kg of xylazine intravenously, and the cows in the fifth group were positioned so that their forelimbs were 30 cm lower than their hindlimbs during the administration of the magnet. The passage of the magnet through the oesophagus was timed with a stopwatch and monitored with a compass. In the control group the magnet passed through in less than 60 seconds, but in four of the cows receiving either atropine or xylazine intravenously, or having their forelimbs positioned lower than their hindlimbs, it took longer than 60 seconds. In the cows receiving atropine subcutaneously or scopolamine intravenously, it took the same time as in the control group. All the cows were radiographed one-and-a-half hours after the administration of the magnet to determine its location. In seven of the 10 cows in the control group, the magnet was located in the reticulum, but in the other three it was in the cranial dorsal blind sac of the rumen. In the other five groups the magnet was located in the reticulum of between four and seven of the 10 cows, but in the cranial dorsal sac of the rumen, the rumen or in other sites in the other cows.

Ultrasound-guided catheterization of the portal vein in 11 cows using the Seldinger technique

Catheterization of the portal vein using the Seldinger technique [Acta Radiol. (1958) 38, 368] was performed in 11 cows. Ultrasound-guided percutaneous portocentesis, using a 25-cm, 14-gauge steel cannula, was performed from the 10th, 11th or 12th intercostal space on the right side. A stylet was placed through the cannula, which was then removed, and a polyurethane balloon-tipped catheter was advanced over the stylet into the portal vein and sutured to the skin (Seldinger, 1952). Blood samples were collected from the catheter at least once daily. The catheter was removed 9-15 days later when blood could no longer be aspirated. The cows were then slaughtered and a post-mortem examination was performed. During the study, appetite remained normal in nine of 11 cows. In three cows, the general behaviour and demeanour were mildly, but transiently, abnormal. Four cows had leucopoenia. The most frequently encountered problem was occlusion of the catheter, which usually was resolved by flushing with heparinized saline. The most common post-mortem lesion observed was an increase in fibrous connective tissue at the site of cannulation. In nine of 11cows, there was a thrombus in the portal vein at the site of catheterization. Generally, the severity of the lesions was mild. The results of this study demonstrated that ultrasound-guided percutaneous catheterization of the portal vein, using the Seldinger technique, is possible in cows. The catheter may be left in place for collection of blood samples for up to 15 days.

The influence of a fermentation-resistant glucose diet on the glucose concentration and other metabolites in portal and jugular blood in cows

The goal of this study was to determine the effect of fermentation-resistant glucose on the glucose concentration and other metabolites in portal and jugular blood in 15 non-lactating cows. In all cows, an indwelling catheter was placed in the left jugular vein and the portal vein for collection of blood samples. Five control cows were fed hay as a normal diet, five control cows were fed straw to induce an energy deficit and five cows were fed hay and they received additionally 2000 g of a fermentation-resistant D-glucose product. The glucose concentration in jugular and portal blood was not influenced by feeding. The concentration of urea and bile acids were significantly higher in portal blood than jugular blood. There was no difference between portal and jugular blood of glucose and total solids. Diet had a significant effect on the concentrations of ammonia, urea, free fatty acids and triglycerides. The concentrations of ammonia and urea were higher in blood of cows fed straw than in blood of cows fed either hay or a fermentation-resistant glucose product. The concentration of urea remained constant in cows fed hay, but increased in cows fed straw and decreased in cows fed a fermentation-resistant glucose product. The concentration of free fatty acids and triglycerides were significantly higher in cows fed a fermentation-resistant glucose product than in cows fed hay. In the present study, a single administration of 300 g of fermentation-resistant glucose did not affect the concentration of blood glucose. Therefore, despite ongoing promotion of such products, there is no indication at this time that administration of fermentation-resistant glucose to cows at the start of lactation results in an increase in blood glucose concentration.

Innovative technologies for decentralised water-, wastewater and biowaste management in urban and peri-urban areas

Avoiding the comingling of water flows coming from different sources and thus obtaining flows with a very low dilution factor is the first and major step key to technical solutions for adequate treatment of household wastewaters. Through their decentral structure and effective recovery of water, energy and fertiliser these systems can be highly cost efficient. Fresh water consumption can be reduced by up to 80% while nutrients can be recovered to a large extent. Source control is also advantageous for hygienic reasons: low volumes are far easier to sanitise. Source separation technology in municipal waste water treatment does often lead decentralised or semicentral systems. The first essential step is the separate collection and treatment of toilet waste in households, which contains almost all pathogens and nutrients. New toilet systems with very low dilution factors, ranging from vacuum- through urine sorting to dry toilets, have been introduced in several projects and proven feasible. New ideas such as the black- and greywater cycle systems are presently under research at the Technical University Hamburg Harburg. Such modular, integrated and small scale systems are only possible through recent advances in membrane technology and, due to their small scale, do have the potential to be installed in densely populated regions. These technologies are options for following the principles of ecological sanitation, to contain, to sanitise and to reuse also in urban areas (EcoSanRes, 2003).

Klinische Befunde bei vier Rindern mit offener Gehirnverletzung

In der vorliegenden Arbeit werden die Befunde bei vier Rindern mit Stirnverletzungen, die auch das Gehirn betrafen, beschrieben. Die Tiere waren eineinhalb bis fünf Jahre alt. Zwei Tiere waren wegen fieberhafter Indigestion in die Klinik eingeliefert worden, bei zwei Tieren hatte der Besitzer bereits vor der Einlieferung eine Stirnverletzung bemerkt. Die klinische Untersuchung ergab bei allen Rindern ein mittelbis hochgradig gestörtes Allgemeinbefinden. Bei drei Kühen war das Sehvermögen einseitig und bei einer Kuh beidseitig aufgehoben, bei jeweils zwei Kühen bestand Linksdrang, Schiefhaltung des Kopfes bzw. eine ein- oder beidseitige Ptosis. Alle Tiere hatten im rechten Os frontale eine perforierende, das Gehirn mit betreffende Stirnverletzung. Zwei von drei untersuchten Liquorproben zeigten sich entzündlich verändert. Alle Kühe wurden notgeschlachtet, zwei davon nach erfolgloser Behandlung. Pathologischanatomisch ließen sich ausgedehnte, zum Teil abszedierende, von der Perforationsstelle ausgehende Veränderungen im Bereich des Großhirns feststellen. Zwei Tiere wiesen zusätzlich eine rechtsseitige eitrige Sinusitis frontalis auf. Als Ursache wurde bei drei Kühen ein Hornstoß und bei einem Rind die Verletzung durch einen spitzen Gegenstand vermutet. Um Stirnverletzungen zuverlässig zu erkennen, muss bei jedem Tier mit zentralnervösen Symptomen auch eine Palpation der Stirnoberfläche durchgeführt werden.