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T Perl

Publications and source records attributed to T Perl.

At least 19 recordsLinked to original sources
PubMed2006

[Perioperative thermal management].

Perioperative hypothermia can influence clinical outcome negatively. It triples the incidence of adverse myocardial outcomes, significantly increases perioperative blood loss, significantly augments allogenic transfusion requirements, and increases the incidence of surgical wound infections. The major causes are redistribution of heat from the core of the body to the peripheral tissues and a negative heat balance. Adequate thermal management includes preoperative and intraoperative measures. Preoperative measures, e.g., prewarming, enhance heat content of the peripheral tissues, thereby reducing redistribution of heat from the core to the peripheral tissues after induction of anesthesia. Intraoperative measures are active skin surface warming of a large body surface area with conductive or convective warming systems. Intravenous fluids should be warmed when large volumes of more than 500-1000 ml/h are required. The body surfaces that cannot be actively warmed should be insulated. Airway humidification and conductive warming of the back are less efficient.

Anesthesia↗
PubMed2005

[The applicability of the ProSeal laryngeal mask airway for laparotomies].

OBJECTIVE: The ProSeal laryngeal mask airway (PLMA) has some design features, which in contrast to the classic LMA allow separation of the respiration from the gastrointestinal canal, a higher leak pressure and a better position assessment. It can be debated if these instrumental improvements justify the application of the PLMA for elective abdominal surgery in cases without aspiration risk. Insertion of airway instruments and gastric tube with regard to insertion time and difficulties and frequency of side effects were to be compared for the tracheal tube and the PLMA. The pharyngolaryngeal morbidity for both methods was also of interest. It was approached with direct and indirect postoperative interview techniques. METHODS: 65 patients were investigated both at the university hospital and at the hospital Neu-Bethlehem in Goettingen. The surgical intervention was a surgical or gynecological laparotomy. Anaesthesia was performed with a standardized application of propofol, alfentanil and rocuronium. Glycopyrroniumbromide was applied to minimize salivation. A total of 34 patients received the PLMA, 31 were intubated. All of them were provided with a gastric tube. RESULTS: The insertion of the PLMA took 70 seconds (21 - 234) on average, the intubation 57 seconds (35 - 145). Endotracheal intubation was accomplished in a shorter time period, but there was no significant difference in comparison with the PLMA-group (p = 0.1924). Insertion of the PLMA was significantly more difficult than oral intubation (p = 0.0006). The base of the tongue and the dorsal pharyngeal wall, but not the vocal cords or the epiglottis were visible in those cases, where the PLMA could not be positioned at all. Here the tip of the cuff was bended. The time period for positioning of the gastric tube was 38 seconds (15 - 75) in the PLMA- and 57 seconds (22 - 219) in the tracheal tube group. With these results the gastric tube positioning was accomplished in a significantly shorter time period in the PLMA-group (p = 0.0267), but not at a significantly higher level of difficulty for endotracheal intubation (p = 0,6247). In one case there was regurgitation through the drainage tube without aspiration before gastric tube placement. At the direct interview 16 patients in the PLMA-group and 23 of the tube group mentioned postoperative throat symptoms. The most frequent symptom was hoarseness (11 PLMA- and 18 intubated patients). There was no significant difference between PLMA- and tracheal tube application with regard to the total number of patients with pharyngolaryngeal morbidity and the frequency of single symptoms. The same is true for the degree of the symptoms. There was a tendency for a longer prevalence of throat symptoms after intubation, but no significant difference. CONCLUSION: In this investigation the PLMA could be successfully applied for elective laparotomies in cases without the risk of aspiration. Proper patient selection and a deep level of anaesthesia are important. The advantage for patients receiving the PLMA is a smooth recovery without cough, but not so much a reduced amount of pharyngolaryngeal morbidity. From this observation it might be concluded that the invasiveness of the surgical intervention might also influence the tolerance for the airway instrument. The disadvantage in this study was the more difficult insertion of the PLMA compared with the oral intubation. Further studies with a larger number of patients must show if these first results of the "Proseal"-LMA for lararotomies are to be confirmed.

Adolescent↗
PubMed2004

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.

Air↗
PubMed2004

[Heat transfer by conductive warming with circulating-water mattresses].

AIM OF THE STUDY: To determine the heat transfer by circulating-water mattresses placed under the back and over both legs of human volunteers. METHODS: With approval by the local ethics committee and informed consent eight minimally clothed volunteers were included in the study. Six calibrated heat flux transducers were placed on the back and additionally eight sensors were placed on both legs of each volunteer. The volunteers reclined on a circulating-water mattress (ComfortPad Plus(R), Cincinnati Sub-Zero Products Inc., Cincinnati, OH, USA) coated with gel (Granulab International, Armersfoort, Niederlande). Another circulating-water mattress (Plastipad trade mark, Cincinnati Sub-Zero Products Inc.) was placed over both legs. Both devices were heated to 41 degrees C by a hypo-hyperthermia system (Hico-Variotherm 530, Hirtz and Co. Hospitalwerk, Cologne, Germany). Heat flux data were sampled during steady-state conditions. After determination of the contact area between the mattresses and the skin, heat transfer was calculated by multiplication of the heat flux per area by the contact area. RESULTS: Heat flux per area to the back was 45.6 +/- 4.5 W m (- 2), the contact area was 0.39 +/- 0.03 m (2). This resulted in a heat transfer of 18.0 +/- 2.4 W. Heat flux per area to the legs was 24.7 +/- 4.3 W m (- 2), the contact area was 0.12 +/- 0.01 m (2). This resulted in a heat transfer of 2.9 +/- 0.6 W. CONCLUSION: The heat transfer of the circulating-water mattress to the back was much higher than the heat transfer to the legs. Nevertheless, model calculations show that conductive warming of the legs is more important for the prevention of perioperative hypothermia than conductive warming of the back, because it has a higher impact on the heat balance.

Adult↗
PubMed2003

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.

Adult↗
PubMed2003

Comparison of forced-air warming systems with lower body blankets using a copper manikin of the human body.

BACKGROUND: Forced-air warming has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with lower body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of six complete lower body warming systems. METHODS: Heat transfer of forced-air warmers can be described as follows:[1]Qdot;=h.DeltaT.A where Qdot; = heat transfer [W], h = heat exchange coefficient [W m-2 degrees C-1], DeltaT = temperature gradient between blanket and surface [ degrees C], A = covered area [m2]. We tested the following forced-air warmers in a previously validated copper manikin of the human body: (1) Bair Hugger and lower body blanket (Augustine Medical Inc., Eden Prairie, MN); (2) Thermacare and lower body blanket (Gaymar Industries, Orchard Park, NY); (3) WarmAir and lower body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (4) Warm-Gard(R) and lower body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (5) Warm-Gard and reusable lower body blanket (Luis Gibeck AB); and (6) WarmTouch and lower body blanket (Mallinckrodt Medical Inc., St. Luis, MO). Heat flux and surface temperature were measured with 16 calibrated heat flux transducers. Blanket temperature was measured using 16 thermocouples. DeltaT was varied between -10 and +10 degrees C and h was determined by a linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, because similar mean skin temperatures have been found in volunteers. The area covered by the blankets was estimated to be 0.54 m2. RESULTS: Heat transfer from the blanket to the manikin was different for surface temperatures between 36 degrees C and 38 degrees C. At a surface temperature of 36 degrees C the heat transfer was higher (between 13.4 W to 18.3 W) than at surface temperatures of 38 degrees C (8-11.5 W). The highest heat transfer was delivered by the Thermacare system (8.3-18.3 W), the lowest heat transfer was delivered by the Warm-Gard system with the single use blanket (8-13.4 W). The heat exchange coefficient varied between 12.5 W m-2 degrees C-1 and 30.8 W m-2 degrees C-1, mean DeltaT varied between 1.04 degrees C and 2.48 degrees C for surface temperatures of 36 degrees C and between 0.50 degrees C and 1.63 degrees C for surface temperatures of 38 degrees C. CONCLUSION: No relevant differences in heat transfer of lower body blankets were found between the different forced-air warming systems tested. Heat transfer was lower than heat transfer by upper body blankets tested in a previous study. However, forced-air warming systems with lower body blankets are still more effective than forced-air warming systems with upper body blankets in the prevention of perioperative hypothermia, because they cover a larger area of the body surface.

Air Movements↗
PubMed2002

Comparison of forced-air warming systems with upper body blankets using a copper manikin of the human body.

BACKGROUND: Forced-air warming with upper body blankets has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with upper body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of eight complete upper body warming systems and to gain more insight into the principles of forced-air warming. METHODS: Heat transfer of forced-air warmers can be described as follows: Qdot;=h. DeltaT. A, where Qdot;= heat flux [W], h=heat exchange coefficient [W m-2 degrees C-1], DeltaT=temperature gradient between the blanket and surface [ degrees C], and A=covered area [m2]. We tested eight different forced-air warming systems: (1) Bair Hugger and upper body blanket (Augustine Medical Inc. Eden Prairie, MN); (2) Thermacare and upper body blanket (Gaymar Industries, Orchard Park, NY); (3) Thermacare (Gaymar Industries) with reusable Optisan upper body blanket (Willy Rüsch AG, Kernen, Germany); (4) WarmAir and upper body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (5) Warm-Gard and single use upper body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (6) Warm-Gard and reusable upper body blanket (Luis Gibeck AB); (7) WarmTouch and CareDrape upper body blanket (Mallinckrodt Medical Inc., St. Luis, MO); and (8) WarmTouch and reusable MultiCover trade mark upper body blanket (Mallinckrodt Medical Inc.) on a previously validated copper manikin of the human body. Heat flux and surface temperature were measured with 11 calibrated heat flux transducers. Blanket temperature was measured using 11 thermocouples. The temperature gradient between the blanket and surface (DeltaT) was varied between -8 and +8 degrees C, and h was determined by linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, as similar mean skin surface temperatures have been found in volunteers. The covered area was estimated to be 0.35 m2. RESULTS: Total heat flow from the blanket to the manikin was different for surface temperatures between 36 and 38 degrees C. At a surface temperature of 36 degrees C the heat flows were higher (4-26.6 W) than at surface temperatures of 38 degrees C (2.6-18.1 W). The highest total heat flow was delivered by the WarmTouch trade mark system with the CareDrape trade mark upper body blanket (18.1-26.6 W). The lowest total heat flow was delivered by the Warm-Gard system with the single use upper body blanket (2.6-4 W). The heat exchange coefficient varied between 15.1 and 36.2 W m-2 degrees C-1, and mean DeltaT varied between 0.5 and 3.3 degrees C. CONCLUSION: We found total heat flows of 2.6-26.6 W by forced-air warming systems with upper body blankets. However, the changes in heat balance by forced-air warming systems with upper body blankets are larger, as these systems are not only transferring heat to the body but are also reducing heat losses from the covered area to zero. Converting heat losses of approximately 37.8 W to heat gain, results in a 40.4-64.4 W change in heat balance. The differences between the systems result from different heat exchange coefficients and different mean temperature gradients. However, the combination of a high heat exchange coefficient with a high mean temperature gradient is rare. This fact offers some possibility to improve these systems.

Bedding and Linens↗
PubMed2000

[Value of reflecting disposable insulation (Thermodrape) in preventing perioperative hypothermia].

OBJECTIVE: The aim of the study was to evaluate the value of reflecting disposable insulation for the prevention of perioperative hypothermia. METHODS: After approval by the local ethics committee 36 patients undergoing long lasting urological intraabdominal surgery were studied. Anaesthesia was performed using etomidate, fentanyl, midazolam, pancuronium and succinylcholine. Patients were randomly assigned to 4 groups. These groups were treated as follows: Gr. 1: Infusion warmer (Hotline HL-90 with System L-70, Level 1 Technologies Inc., Marshfield, USA) and standard O.R. draping with two layers of cotton drapes. Gr. 2: Infusion warmer and reflecting disposable insulation (Thermadrape, O.R. Concepts Inc., Roanoke, USA) covering the legs, upper body, arms and head. Gr. 3: Infusion warmer and convective air warming with upper body blanket (WarmTouch, Mallinckrodt Medical, Hennef/Sieg, Germany). Gr. 4: Infusion warmer, convective air warming and reflecting disposable insulation. RESULTS: After 2 hours of surgery patients of groups 1 and 2 became hypothermic with core temperatures of 35.1 and 35.6 degrees C respectively. No relevant difference could be found between the two groups. The combination of an infusion warmer and convective air warming was an effective method to prevent hypothermia in groups 3 and 4. After 2 hours of surgery these patients had core temperatures of 36.6 and 36.4 degrees C respectively. Reflecting disposable insulation did not improve the effect of convective air warming. CONCLUSION: Reflecting disposable insulation was insufficient in the investigated operative setting.

Adult↗
PubMed1999

Smallpox as a biological weapon: medical and public health management. Working Group on Civilian Biodefense.

OBJECTIVE: To develop consensus-based recommendations for measures to be taken by medical and public health professionals following the use of smallpox as a biological weapon against a civilian population. PARTICIPANTS: The working group included 21 representatives from staff of major medical centers and research, government, military, public health, and emergency management institutions and agencies. Evidence The first author (D.A.H.) conducted a literature search in conjunction with the preparation of another publication on smallpox as well as this article. The literature identified was reviewed and opinions were sought from experts in the diagnosis and management of smallpox, including members of the working group. CONSENSUS PROCESS: The first draft of the consensus statement was a synthesis of information obtained in the evidence-gathering process. Members of the working group provided formal written comments that were incorporated into the second draft of the statement. The working group reviewed the second draft on October 30, 1998. No significant disagreements existed and comments were incorporated into a third draft. The fourth and final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members. CONCLUSIONS: Specific recommendations are made regarding smallpox vaccination, therapy, postexposure isolation and infection control, hospital epidemiology and infection control, home care, decontamination of the environment, and additional research needs. In the event of an actual release of smallpox and subsequent epidemic, early detection, isolation of infected individuals, surveillance of contacts, and a focused selective vaccination program will be the essential items of an effective control program.

Biological Warfare↗
PubMed1998

Risk factors and clinical impact of central line infections in the surgical intensive care unit.

OBJECTIVE: To determine the risk factors and clinical impact of central line infections in critically ill surgical patients. DESIGN: Retrospective study. SETTING: The surgical intensive care unit of a large tertiary care university hospital. PATIENTS: A total of 232 consecutive central line catheters sent for culture from patients in a surgical intensive care unit during 1996 and 1997. Catheters were sent for microbiologic analysis when the patient was clinically infected and the central line was a possible source. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Risk factors associated and clinical impact of a positive catheter culture. RESULTS: Of 232 consecutive catheters from 93 patients sent for microbiologic analysis, 114 catheters (49%) had no growth, 40 (17%) were colonized (<15 colonies), and 78 (34%) were considered infected (> or =15 colonies). Univariate analysis showed that site (internal jugular vs subclavian, P<.001), catheter use (monitoring > dialysis > fluid > nutrition, P=.006), placement in the operating room vs the intensive care unit (P=.02), and placement of a new catheter (> guide wire, > new site, P=.003) were all significant factors. Surprisingly, neither the number of lunmens nor the duration of the catheter in situ were predictors when a catheter was suspected and not proved infected compared with a suspected and proved catheter infection. In the multiple regression model, the placement of the catheter in the internal jugular position was the single most important predictor of a catheter infection (P<.001; odds ratio, 1.83; 95% confidence interval [CI], 1.41-2.37). The presence or absence of a specific clinical sign of infection was not predictive of a proved catheter infection. Eighty-six percent of patients had gram-positive bacteria identified on the culture, while the remaining patients had gram-negative bacteria or Candida identified. Of the catheter infections, 68% were monomicrobial, whereas 32% were polymicrobial. Of the catheters sent for microbiologic analysis, 209 (90%) had concurrent peripheral blood cultures for analysis. Nineteen (32%) with no growth from the catheter, and 14 (23%) of colonized catheters had concurrent bacteremia; all had another identifiable cause of infection. Twenty-seven (45%) of infected catheters had a concurrent bacteremia, and 9 of 27 had a second site positive for the same organism. Death related to the infection occurred in 15 patients, 2 in the first 72 hours and 13 in the following 14 days. CONCLUSIONS: Central line infections remain an important cause of morbidity and mortality. Comprehensive review of hospital practices may show a directed focus for performance improvement practices. At our institution, internal jugular catheters have the highest rate of infection. This may suggest breaks in technique during catheter insertion or during catheter maintenance and care.

Analysis of Variance↗
PubMed1984

Post-cataract astigmatism with and without the use of the Terry keratometer.

Measured and induced post-cataract astigmatism was compared in 15 eyes prior to the purchase of a Terry keratometer , in 62 eyes with the keratometer , and subsequently in 36 eyes without the keratometer . All groups received the same preoperative and postoperative care. The surgical techniques were the same and were performed by a single surgeon. We found no significant difference between cases performed with and cases performed without the Terry keratometer at various postoperative gates. Seventy-five percent of the cases performed without the keratometer had less than 2 diopters of induced astigmatism, whereas 62% of the cases performed with the Terry keratometer achieved the same level of astigmatism 6 to 8 weeks postoperatively. The lack of difference between these two groups is due to biological variables which affect intraoperative readings and postoperative wound healing.

Astigmatism↗
PubMed1982

Controlled reduction of postkeratoplasty astigmatism.

Corneal transplants were performed in 50 eyes using eight deeply placed interrupted 24 micron (10--0) monofilament nylon sutures followed by a more superficial continuous 16 micron (11--0) monofilament nylon suture placed around the wound in 16 equal bites. After surgery the 24 micron sutures in the steepest corneal meridian based on central and peripheral keratometry were cut. This suture technique permitted the donor cornea to assume its normal shape more rapidly while reducing the induced postkeratoplasty astigmatism. With this technique corneal astigmatism was reduced an average of 3.4 diopters (range 0--10 diopters), which allowed patient to achieve a mean visual acuity at three months of 20/50 and at 11 to 13 months of 20/35. Although this suture technique does not eliminate postkeratoplasty astigmatism, it permits the surgeon to reduce actively high degrees of astigmatism present after corneal transplantation.

Adult↗
PubMed1982

The natural and modified course of post-cataract astigmatism.

We performed sequential central keratometry on 52 cataract patients for six months. We found no statistically significant difference in the induced postoperative astigmatism between wound closure with interrupted and double shoelace running closure with 10-0 monofilament nylon. In 31 patients, the postoperative astigmatism was always with-the-rule. In 21 patients who underwent wound closure with 8-0 polyglactin suture, we documented a postoperative shift in induced astigmatism from with- to against-the-rule which took place between the fourth and fifth postoperative week. Based on our present study of the natural and modified course of post-cataract astigmatism and based upon previous research, we feel the cataract surgeon now has the appropriate means to reduce and/or control post-cataract astigmatism.

Astigmatism↗
PubMed1981

Disparate diameter grafting. Astigmatism, intraocular pressure, and visual acuity.

We studied 180 consecutive corneal transplants performed by one surgeon to determine the benefit obtained by using a 0.5 mm oversize (OS) graft. We compared 61 same size (SS) grafts to 119 oversize (OS) grafts, with a mean follow-up time of 24 and 13 months respectively. While the refractive error, recovery of visual acuity, and intraocular pressure were similar in both groups, the astigmatism was found to be significantly elevated in the (OS) group. Using a 0.5 mm oversize graft did not afford any protection against postkeratoplasty glaucoma, did not increase the speed of recovery of the patients' visual acuity, but produced significantly more astigmatism than a same size graft.

Adult↗