Does preoperative locally applied estrogen treatment facilitate prolapse-associated symptoms in postmenopausal women with symptomatic pelvic organ prolapse? A randomised controlled double-masked, placebo-controlled, multicentre study.

OBJECTIVE: To evaluate whether locally applied vaginal estrogen affects prolapse-associated complaints compared with placebo treatment in postmenopausal women prior to surgical prolapse repair. DESIGN: Randomised, double-masked, placebo-controlled, multicentre study. SETTING: Urogynaecology unit at the Medical University of Vienna and University Hospital of Tulln. POPULATION: Postmenopausal women with symptomatic pelvic organ prolapse and planned surgical prolapse repair. METHODS: Women were randomly assigned local estrogen cream or placebo cream 6 weeks preoperatively. MAIN OUTCOME MEASURES: The primary outcome was differences in subjective prolapse-associated complaints after 6 weeks of treatment prior to surgery, assessed with the comprehensive German pelvic floor questionnaire. Secondary outcomes included differences in other pelvic floor-associated complaints (bladder, bowel or sexual function). RESULTS: Out of 120 women randomised, 103 (86%) remained for the final analysis. After 6 weeks of treatment the prolapse domain score did not differ between the estrogen and the placebo groups (4.4 ± 0.19 versus 4.6 ± 0.19; mean difference, -0.21; 95% CI -0.74 to 0.33; P = 0.445). Multivariate analysis, including only women receiving the intervention, showed that none of the confounding factors modified the response to estradiol. CONCLUSIONS: These results demonstrate that preoperative locally applied estrogen does not ameliorate prolapse-associated symptoms in postmenopausal women with symptomatic pelvic organ prolapse. TWEETABLE ABSTRACT: Preoperative local estrogen does not ameliorate prolapse-associated symptoms in postmenopausal women with pelvic organ prolapse.

Randomised controlled trial comparing preoperative carbohydrate loading with standard fasting in paediatric anaesthesia.

BACKGROUND: Preoperative fasting is a major cause of perioperative discomfort in paediatric anaesthesia and leads to postoperative insulin resistance, thus potentially enhancing the inflammatory response to surgery. Addressing these problems by preoperative carbohydrate intake has not been a well-defined approach in children. METHODS: We randomised 120 children scheduled for gastroscopy under general anaesthesia to either a control group of standard preoperative fasting or a study group receiving a carbohydrate beverage (PreOp™; Nutricia, Erlangen, Germany). Their stomach contents were aspirated endoscopically, and the volume and pH measured. Perioperative discomfort was evaluated using, among other parameters, an observational pain scale in ≤4-yr-olds and a VAS in >4-yr-olds. The investigators doing the endoscopies and outcome evaluations were blinded to the study group allocation. RESULTS: Compared with fasting, carbohydrate loading was associated with significantly less gastric content (P=0.01), fewer patients experiencing postoperative nausea (P=0.028), with no significant difference in postoperative vomiting. High preoperative VAS scores (>5) were recorded for only one child in the carbohydrate group vs five children in the fasting group. Bowel cleansing for simultaneous colonoscopies (n=61) made no difference to any of the intergroup findings. CONCLUSIONS: Preoperative carbohydrates can reduce nausea and gastric content, the latter being a surrogate parameter for the risk and severity of gastric aspiration into the lungs during anaesthesia. Our study adds knowledge for preoperative fasting guidelines in paediatric anaesthesia. CLINICAL TRIAL REGISTRATION: DRKS00005020.

An observational study of the macro- and micro-haemodynamic implications of epidural anaesthesia in children.

The haemodynamic implications of epidural anaesthesia in children are poorly documented. We report macro- and micro-haemodynamic data from an observational study of 25 children ranging from neonates to six-years old, who underwent surgery conducted with a specific combination of monitoring systems. We analysed 90 min of study-related monitoring after epidural catheterisation, with skin incision taking place after around 30 min. We recorded macrohaemodynamic parameters (monitored using LiDCOrapid) including heart rate, mean arterial pressure, cardiac output, stroke volume, systemic vascular resistance and stroke volume variation. Microhaemodynamic parameters (monitored using Invos™) included cerebral and peri-renal oxygenation. Based on the entire 90 min of study-related monitoring, we found significant increases in cardiac output (p = 0.009), stroke volume (p = 0.006) and stroke volume variation (p = 0.008), as well as decreases in systemic vascular resistance (p = 0.007) around 30 min after epidural blockade. There were no significant changes in heart rate, arterial pressure and cerebral or peri-renal oxygenation during these 90 min. Considering that the microhaemodynamic parameters were not affected by the macrohaemodynamic changes, we conclude that autoregulation of the brain and the kidneys was maintained in children under epidural anaesthesia.

A retrospective analysis of 509 consecutive interscalene catheter insertions for ambulatory surgery.

Effective pain therapy after shoulder surgery is the main prerequisite for safe management in an ambulatory setting. We evaluated adverse events and hospital re-admission using a database of 509 interscalene catheters inserted during ambulatory shoulder surgery. Adverse events were recorded for 34 (6.7%) patients (9 (1.8%) catheter dislocations diagnosed in the recovery room, 9 (1.8%) catheter dislocations at home with pain, 2 (0.4%) pain without catheter dislocation, 1 (0.2%) 'secondary' pneumothorax without intervention and 13 (2.6%) other). Twelve (2.4%) patients were re-admitted to hospital (8 (1.6%) for pain, 2 (0.4%) for dyspnoea and 2 (0.4%) for nausea and vomiting), 9 of whom had rotator cuff repair. A well-organised infrastructure, optimally trained medical professionals and appropriate patient selection are the main prerequisites for the safe, effective implementation of ambulatory interscalene catheters in routine clinical practice.

Bacterial contamination of water used as thermal transfer fluid in fluid-warming devices.

INTRODUCTION: Recent reports implicated heater-cooler units (HCUs), which are used for warming infusions, blood or in extracorporeal membrane oxygenation devices, as a possible origin of healthcare-associated infections (HAIs) with potentially pathogenic bacteria, such as non-tuberculous mycobacteria [1]. This represents a source of contamination in a usually sterile setting. AIM: To analyse water from infusion heating devices (IHDs) for bacterial contamination, and to determine if IHDs are a potential source in the transmission of HAIs. METHODS: Thermal transfer fluid (TTF; 300-500 mL) was collected from the reservoirs of 22 independent IHDs and processed on different selective and non-selective media for colony count and identification of bacteria. Strains of Mycobacterium spp. were analysed by whole-genome sequencing. RESULTS: Bacterial growth was observed in all 22 TTF samples after cultivation at 22 °C and 36 °C. Pseudomonas aeruginosa was the most frequent pathogen identified, present in 13.64% (3/22) of samples at >100 colony-forming units/100 mL. Colonization with Mycobacterium chimaera, Ralstonia pickettii and Ralstonia mannitolilytica was detectable in 9.09% (2/22) of samples. Primary sequencing of the detected M. chimaera suggests a close relationship with a M. chimaera strain detected in an outbreak in Switzerland which led to the death of two patients. DISCUSSION: Contamination of TTF represents a germ reservoir in a sensitive setting. Handling errors of IHDs may lead to the distribution of opportunistic or facultative bacterial pathogens, increasing the risk of transmission of nosocomial infections.

Ultrasound assessment of cranial spread during caudal blockade in children: effect of the speed of injection of local anaesthetics.

BACKGROUND: Despite caudal blockade being the most widely used regional anaesthetic procedure for infants and children undergoing subumbilical surgery, the question whether the injection velocity of the local anaesthetic itself affects its spread in the epidural space has not yet been investigated. Thus, the aim of the present study was to measure the cranial spread of caudally administered local anaesthetics in infants and children by means of real-time ultrasonography, with a special focus on comparing the effect of using two different speeds of injection. METHODS: Fifty ASA I-II infants and children, aged up to 6 yr, weighing up to 25 kg, undergoing subumbilical surgery, were enrolled in this prospective, randomized, observer-blinded study. Caudal blockade was performed under ultrasound observation using ropivacaine 1 ml kg(-1) 0.2% or 0.35% and an injection given at either 0.25 ml s(-1) or 0.5 ml s(-1), respectively. RESULTS: Ultrasound observation of the local anaesthetic flow and the extent of cranial spread was possible in all patients. All caudal blocks were considered successful, and all surgical procedures could be completed without any indications of insufficient analgesia. No statistically significant difference could be observed between the two injection speeds regarding the cranial spread of the local anaesthetic in the epidural space. CONCLUSIONS: The main finding of the present study is that the speed of injection of the local anaesthetic does not affect its cranial spread during caudal blockade in infants and children. Therefore, the prediction of the cranial spread of the local anaesthetic, depending on the injection speed, is not possible.

Perioperative treatment algorithm for bleeding burn patients reduces allogeneic blood product requirements.

BACKGROUND: Surgical excision of burn wounds is often associated with severe bleeding. Timely and targeted correction of coagulopathy reduces transfusion requirements and improves survival in trauma victims. We hypothesized that rapid correction of coagulopathy after a treatment algorithm based on point-of-care viscoelastic coagulation testing would decrease allogeneic blood product transfusions during surgical excision of burn wounds. METHODS: Thirty consecutive patients undergoing surgical excision of burn wounds were enrolled into this prospective, randomized, controlled, single-centre study. In the control group, coagulation management was performed according to the clinicians' discretion. For the algorithm group, we standardized treatment based on the Austrian recommendation for the management of trauma-induced coagulopathy using point-of-care rotational thromboelastometry (ROTEM(®)). The main outcome parameter was the cumulative number of allogeneic blood units transfused on the day of surgery. RESULTS: The difference between the groups regarding the cumulative use of allogeneic blood products was highly significant with 3.0 (1.3-5.5) blood products in the algorithm group compared with 9.0 (6.0-12.3) in the control group [median (inter-quartile range); P=0.002]. No plasma was administered in the algorithm group compared with 5.0 (1.5-7.5) units overall in the control group (P<0.001). Fibrinogen concentrate administration was not significantly different between the groups (P=0.89). Tranexamic acid was not administered. CONCLUSIONS: The significant reduction in allogeneic blood product requirements during surgical burn wound excision is a prospective proof of concept that a bleeding management algorithm based on thromboelastometry is efficacious. Hypofibrinogenaemia and hyperfibrinolysis are not significant pathomechanisms of bleeding in this setting and ROTEM(®) helps to avoid unnecessary interventions.

Effect of preoperative fever-range whole-body hyperthermia on immunological markers in patients undergoing colorectal cancer surgery.

BACKGROUND: Previous studies have demonstrated beneficial immunological effects of fever-range whole-body hyperthermia (FR-WBH) as an adjunct to non-surgical cancer therapy. We conducted a study of preoperative FR-WBH in patients undergoing colorectal cancer surgery to evaluate perioperative, hyperthermia-induced immunomodulation. METHODS: The trial was conducted as a subject-blinded, controlled, randomized study. Subjects in the FR-WBH group (n=9) were treated with FR-WBH before operation under propofol sedation; the target core temperature was 39 (0.5)°C with 1 h warming and 2 h plateau phase. Subjects in the control group (n=9) were treated with propofol sedation only. Blood samples were acquired before and after treatment, after operation, and 24, 48 h, and 5 days after the end of surgery. The following parameters were measured: lipopolysaccharide (LPS)-induced tumour necrosis factor (TNF)-α, procalcitonin (PCT), interleukin (IL)-6/10, heat shock proteins (HSPs) 60, 70, and 90, human leucocyte antigen-DR (HLA-DR), and LPS-binding protein (LBP). RESULTS: HSPs were increased in the FR-WBH group after treatment [HSP60, 48 h postop: 143 (41)% vs 89 (42)%, P=0.04; HSP90, postop: 111 (33)% vs 64 (31)%, P=0.04; HSP70: P=0.40; FR-WBH vs control, P-values for area under the level/time curve]. TNF-α levels were elevated after surgery in the control group and remained near baseline in the FR-WBH group [24 h postop: 73 (68)% vs 151 (72)%, P=0.04]. PCT increased in both groups 24 h after surgery; in the control group, this increase was significantly higher (P=0.02). There were no significant differences for IL, HLA-DR, or LBP. CONCLUSIONS: The immune system to react to surgical stress, as measured by a panel of laboratory indicators, might be improved by preoperative FR-WBH.

Patient satisfaction with care in the intensive care unit: can we rely on proxies?

BACKGROUND: To investigate whether next of kin can be addressed as proxy to assess patients' satisfaction with care in the intensive care unit (ICU). METHODS: Prospective observational multicentre study. Two hundred and thirty-five patients with an ICU length of stay of ≥2 days and 266 of their adult next of kin participated. Patient satisfaction was assessed by a questionnaire, distributed upon discharge from an ICU and compared with next of kin's answers. The possible range of answers was 0-100, with higher numbers indicating higher satisfaction. The main outcome measure was the extent of agreement between patients' satisfaction with care and the ratings of their next of kin. RESULTS: Patients were most satisfied concerning physicians' competence (86.7±16.3), while least satisfaction was observed for the management of agitation and restlessness (78.2±23.5). There was no significant difference between next of kin's and patients' ratings. Agreement between patients and proxies was the highest concerning overall satisfaction (Cohen's κ 0.40) and the lowest for coordination of care (0.24). Spouses/partners had a higher agreement with the patients' ratings than other proxies. CONCLUSIONS: If the patient is unable to rate his satisfaction with care in the ICU, next of kin may be taken as an appropriate surrogate. TRIAL REGISTRATION: The study has been registered at ClinicalTrials.gov, Reg No: NTC 00890513.

Comparison of the i-gel and the LMA-Unique laryngeal mask airway in patients with mild to moderate obesity during elective short-term surgery.

The aim of our study was to compare leakage pressure, ease and time of insertion of the i-gel and the LMA-Unique laryngeal mask airway in patients with mild to moderate obesity during elective short-term surgery. In this prospective, randomised crossover trial, we included patients with a body mass index (BMI) >25 and <35 kg.m(-2) , and , age >18 years, undergoing elective surgery in the supine position with an expected duration of surgery <2 h. Leakage pressures, insertion difficulty, time and number of insertion attempts were evaluated. We included 50 patients consisting of 29 mildly (BMI>25 and < 30 kg.mg(-2) ) and 21 moderately (BMI>30 and < 35 kg.mg(-2) ) obese patients. Mean (SD) leakage pressures were 23.7 (9.2) cmH2O (i-gel) and 17.4 (7.0) cmH2O (LMA-Unique) (p<0.01). Subgroup analyses showed leakage pressures of 22.2 (9.4) cmH2O (i-gel) and 17.5 (7.5) cmH2O (LMA-Unique) (p=0.013) in the mild subgroup, and 25.7 (8.6) cmH2O (i-gel) and 17.0 (6.2) cmH2O (LMA-Unique) (p<0.01), in the moderate subgroup. Insertion of the i-gel was associated with significantly higher leakage pressures compared with the LMA-Unique in mildly and moderately obese patients.

Development and internal validation of an algorithm to predict intraoperative risk of inadvertent hypothermia based on preoperative data.

Intraoperative hypothermia increases perioperative morbidity and identifying patients at risk preoperatively is challenging. The aim of this study was to develop and internally validate prediction models for intraoperative hypothermia occurring despite active warming and to implement the algorithm in an online risk estimation tool. The final dataset included 36,371 surgery cases between September 2013 and May 2019 at the Vienna General Hospital. The primary outcome was minimum temperature measured during surgery. Preoperative data, initial vital signs measured before induction of anesthesia, and known comorbidities recorded in the preanesthetic clinic (PAC) were available, and the final predictors were selected by forward selection and backward elimination. Three models with different levels of information were developed and their predictive performance for minimum temperature below 36 °C and 35.5 °C was assessed using discrimination and calibration. Moderate hypothermia (below 35.5 °C) was observed in 18.2% of cases. The algorithm to predict inadvertent intraoperative hypothermia performed well with concordance statistics of 0.71 (36 °C) and 0.70 (35.5 °C) for the model including data from the preanesthetic clinic. All models were well-calibrated for 36 °C and 35.5 °C. Finally, a web-based implementation of the algorithm was programmed to facilitate the calculation of the probabilistic prediction of a patient's core temperature to fall below 35.5 °C during surgery. The results indicate that inadvertent intraoperative hypothermia still occurs frequently despite active warming. Additional thermoregulatory measures may be needed to increase the rate of perioperative normothermia. The developed prediction models can support clinical decision-makers in identifying the patients at risk for intraoperative hypothermia and help optimize allocation of additional thermoregulatory interventions.

Caudal anaesthesia under sedation: a prospective analysis of 512 infants and children.

BACKGROUND: Caudal anaesthesia is a common procedure for infants and children undergoing subumbilical surgery, mostly performed in conjunction with general anaesthesia. Even if complications are rare, the risk of postoperative apnoea is significant, especially in infants born preterm or operated upon before 46 weeks of post-conceptual age. Caudal block in sedated, spontaneously breathing patients might be a safe alternative. METHODS: We investigated 512 infants and children. Premedication consisted of midazolam, sedation was induced with i.v. nalbuphine 0.1 mg kg(-1) and propofol 1 mg kg(-1), and maintained with propofol 5 mg kg(-1) h(-1) in children, if necessary. Caudal block was performed with ropivacaine 1 ml kg(-1) (0.2% or 0.35%). RESULTS: Data were obtained from 228 infants and 284 children. Median (IQR) age was 1.3 (0.2, 3.4) yr; median body weight was 10.0 (4.8, 15.3) kg. Two hundred and thirty-three (45.51%) were born preterm and 47 (9.18%) were operated upon before 46 weeks of post-conceptual age. Caudal block was successful in 98.05% and adverse events occurred in 7.03% patients. The incidence of adverse events was not higher in born preterm or operated upon before 46 weeks of post-conceptual age than in term born infants (P=0.35 and 0.35, respectively), or in infants vs children (P=0.61). There was no correlation between the incidence of adverse events and continuous sedation (P=0.07), coexisting diseases (P=0.11), or ASA classification (P=0.33). CONCLUSIONS: Caudal anaesthesia under sedation is associated with high success rates and a low incidence of adverse events, but requires careful and anticipatory perioperative management.

On the ropivacaine-reducing effect of low-dose sufentanil in intrathecal labor analgesia.

BACKGROUND: Combining ropivacaine with sufentanil for intrathecal (i.t.) analgesia in labor is well recognized, but information on dosing is limited. This study aimed to determine the ED 50 of i.t. ropivacaine and to assess the effect of adding defined low doses of sufentanil. METHODS: This was a two-phase, double-blind, randomized and prospective study. One hundred and fifteen parturients receiving combined spinal epidural analgesia were allocated to one of four groups to receive ropivacaine or sufentanil alone or in combination. In phase one, sufentanil dose-response was calculated using logistic regression. In phase two, ED 50 of ropivacaine and of the combination with a fixed dosage of sufentanil at ED 20 and ED 40 was evaluated using the technique of up-down sequential allocation. Analgesic effectiveness was assessed 15 min after injection using a 100 mm visual analog scale, with <10 mm lasting for 45 min defined as effective. Furthermore, side effects and duration were recorded. RESULTS: The ED 50 of i.t. ropivacaine was 4.6 mg [95% confidence intervals (95% CI) 4.28, 5.31]. Adding sufentanil at ED 20 significantly decreased the ED 50 of i.t. ropivacaine to 2.1 mg (95%CI 1.75, 2.5) (P<0.005); at ED 40, the reduction was similar (P<0.005). Combining sufentanil with ropivacaine resulted in a dose-independent prolongation of analgesia. Besides pruritus, which was well tolerated, there were no differences in side effects. CONCLUSION: Adding sufentanil at ED 20 results in a more than 50% dose-sparing effect of ropivacaine and considerably prolongs analgesia. Increasing dosage implicates no clinical benefit.

Exposure to anaesthetic trace gases during general anaesthesia: CobraPLA vs. LMA classic.

BACKGROUND: To prospectively investigate the performance, sealing capacity and operating room (OR) staff exposure to waste anaesthetic gases during the use of the Cobra perilaryngeal airway (CobraPLA) compared with the laryngeal mask airway classic (LMA). METHODS: Sixty patients were randomly assigned to the CobraPLA or the LMA group. Insertion time, number of insertion attempts and airway leak pressures were assessed after induction of anaesthesia. Occupational exposure to nitrous oxide (N(2)O) and Sevoflurane (SEV) was measured at the anaesthetists' breathing zone and the patients' mouth using a photoacoustic infrared spectrometer. RESULTS: N(2)O waste gas concentrations differed significantly in the anaesthetist's breathing zone (11.7+/-7.2 p.p.m. in CobraPLA vs. 4.1+/-4.3 p.p.m. in LMA, P=0.03), whereas no difference could be shown in SEV concentrations. Correct CobraPLA positioning was possible in 28 out of 30 patients (more than one attempt necessary in five patients). Correct positioning of the LMA classic was possible in all 30 patients (more than one attempt in three patients). Peak airway pressure was higher in the CobraPLA group (16+/-3 vs. 14+/-2 cmH(2)O, P=0.01). The average leak pressure of the CobraPLA was 24+/-4 cmH(2)O, compared with 20+/-4 cmH(2)O of the LMA classic (P<0.001; all values means+/-SD). CONCLUSION: Despite higher airway seal pressures, the CobraPLA caused higher intraoperative N(2)O trace concentrations in the anaesthetists' breathing zone.

Accuracy and precision of a novel non-invasive core thermometer.

BACKGROUND: Accurate measurement of core temperature is a standard component of perioperative and intensive care patient management. However, core temperature measurements are difficult to obtain in awake patients. A new non-invasive thermometer has been developed, combining two sensors separated by a known thermal resistance ('double-sensor' thermometer). We thus evaluated the accuracy of the double-sensor thermometer compared with a distal oesophageal thermometer to determine if the double-sensor thermometer is a suitable substitute. METHODS: In perioperative and intensive care patient populations (n=68 total), double-sensor measurements were compared with measurements from a distal oesophageal thermometer using Bland-Altman analysis and Lin's concordance correlation coefficient (CCC). RESULTS: Overall, 1287 measurement pairs were obtained at 5 min intervals. Ninety-eight per cent of all double-sensor values were within +/-0.5 degrees C of oesophageal temperature. The mean bias between the methods was -0.08 degrees C; the limits of agreement were -0.66 degrees C to 0.50 degrees C. Sensitivity and specificity for detection of fever were 0.86 and 0.97, respectively. Sensitivity and specificity for detection of hypothermia were 0.77 and 0.93, respectively. Lin's CCC was 0.93. CONCLUSIONS: The new double-sensor thermometer is sufficiently accurate to be considered an alternative to distal oesophageal core temperature measurement, and may be particularly useful in patients undergoing regional anaesthesia.

Preemptive analgesia by lornoxicam--an NSAID--significantly inhibits perioperative platelet aggregation.

BACKGROUND AND OBJECTIVE: To investigate whether preemptive administered lornoxicam changes perioperative platelet function during thoracic surgery. METHODS: A total of 20 patients scheduled for elective thoracic surgery were randomly assigned to receive either lornoxicam (16 mg, i.v.; n = 10) or placebo (n = 10) preoperatively. All patients underwent treatment of solitary lung metastasis and denied any antiplatelet medication within the past 2 weeks. Blood samples were drawn via an arterial catheter directly into silicone-coated Vacutainer tubes containing 0.5 mL of 0.129 M buffered sodium citrate 3.8% before, 15 min, 4 h and 8 h after the study medication was administered. Platelet aggregation curves were obtained by whole blood electrical impedance aggregometry (Chrono Log). RESULTS: Platelet aggregation was significantly reduced 15 min, 4 h and 8 h after lornoxicam administration compared to placebo (P < 0.05) for collagen, adenosine diphosphate and arachidonic acid as trigger substances. Adenosine diphosphate-induced platelet aggregation decreased by 85% 15 min after lornoxicam administration, and remained impaired for 8 h. CONCLUSION: Platelet aggregation assays are impaired for at least 8 h after lornoxicam application. Therefore perioperative analgesia by use of lornoxicam should be carefully administered under consideration of subsequent platelet dysfunction.

Validity and fidelity of the upper airway in two high-fidelity patient simulators.

BACKGROUND: Human patient simulators are frequently used for airway management training and research. However, little is known about their fidelity and validity. The use of these simulators as a benchmark model remains highly questionable. The objective of this study was to evaluate the validity and fidelity of two patient simulators (compared to actual patients) for anaesthesia residents performing three airway management techniques. METHODS: Endotracheal intubation, laryngeal mask airway insertion and mask ventilation were performed by anaesthesia residents on 80 patients undergoing elective surgery. The anaesthesia residents also used these three techniques to secure the airways of two human patient simulators in a randomised crossover study. The durations, difficulties, realism and success rates of the procedures were assessed. RESULTS: Although the performance of endotracheal intubation was comparable in patients and both manikins, no chest rise was visible in 35% (HAL) and 32.5% (SimMan) of the manikins after inserting a laryngeal mask airway. This result was not observed in patients (P<0.001). Furthermore, effective mask ventilation was not possible in 60% of the cases using HAL, compared with 0% of cases using SimMan and 2.5% of patients (P<0.001). CONCLUSION: Patient simulators are not a valid alternative to human patients for conducting scientific evaluations of supraglottic airway management techniques. HAL and SimMan do have adequate validity for endotracheal intubation, but the fidelity and validity are low when a laryngeal mask is used or if mask ventilation is performed. Therefore, previous simulation-based airway device evaluation studies must be interpreted with great caution.

Influence of hypotensive and normotensive anesthesia on platelet aggregability and hemostatic markers in orthognathic surgery.

This prospective randomized study investigated the influence of normotensive and hypotensive general anesthesia on platelet aggregability, intraoperative blood loss and parameters of plasmatic coagulation during extensive orthognathic surgery. A total of 30 patients were randomly allocated for either normotensive anesthesia maintained by continuous infusion of propofol and remifentanil (NORMO, n=10) or hypotensive anesthesia, whereby hypotension was induced by increasing the infusion rate of remifentanil (HYPO-R, n=10) or by administration of nitroglycerin (HYPO-N, n=10). Whole blood platelet aggregability was significantly reduced during hypotension compared to normotensive anesthesia (P<.01, HYPO-N and HYPO-R vs. NORMO). Mean arterial blood pressure during hypotension correlated well with adenosinediphosphate- (R=.712, P<.001) and collagen-induced platelet aggregability (R=.685, P<.001). Within hypotensive study groups, postoperative fibrinogen levels were significantly different, whereas intraoperative platelet aggregability, postoperative platelet count, prothrombin time, activated partial thromboplastin time and antithrombin levels were not different. Normotensive anesthesia, however, caused significant decreases in platelet count (-29%), prothrombin time (-24%), fibrinogen (-41%) and antithrombin (-28%) and a significant prolongation in activated partial thromboplastin time (+21%) and thrombin time (+18%). There was a trend to reduced intraoperative blood loss in hypotensive study groups; however, differences were not significant. In conclusion, induced hypotension--independent of substances used for induction of hypotension--reduces intraoperative platelet aggregability, subsequently protecting the coagulation system against subclinical consumption coagulopathy. Induced hypotension-caused platelet dysfunction does not lead to an increased intraoperative blood loss, but quite on the contrary shows a trend to reduced intraoperative blood loss, possibly by preventing platelet-induced subclinical consumption coagulopathy.

Expression of matrix metalloproteinases in patients with uterine smooth muscle tumors: an immunohistochemical analysis of MMP-1 and MMP-2 protein expression in leiomyoma, uterine smooth muscle tumor of uncertain malignant potential, and leiomyosarcoma.

OBJECTIVE: Matrix metalloproteinases (MMPs) have been suggested to play an important role in tumor invasion and metastasis. We compared the expression of MMP-1 and MMP-2 protein in patients with leiomyoma, uterine smooth muscle tumor of uncertain malignant potential (STUMP), and leiomyosarcoma (LMS). METHODS: MMP-1 and MMP-2 expression was investigated by immunohistochemistry from paraffin-embedded tissue in 26 patients with leiomyoma, in 24 patients with STUMP, and in 21 patients with LMS. RESULTS: MMP-1 was expressed in 92% of leiomyomas, in 83% of STUMP, and in 86% of LMS, whereas MMP-2 was expressed in 12% of leiomyomas, in 17% of STUMP, and in 48% of LMS. A statistically significant difference regarding the frequency of MMP-2 expression was observed between LMS and STUMP (P =.025) as well as between LMS and leiomyoma (P =.006), but not between STUMP and leiomyoma (P >.05). Likewise, the staining intensity did significantly differ between LMS and leiomyoma (P =.025), but no statistical significant difference was observed between LMS and STUMP (P >.05) and between STUMP and leiomyoma (P >.05). CONCLUSION: The stronger MMP-2 expression in patients with LMS compared with STUMP and leiomyoma indicates that this protein might be a marker for tumor invasion or metastasis in patients with uterine LMS. Furthermore, MMP-2 seems to be a useful immunohistochemical parameter to distinguish cases of smooth muscle tumors in which histologic features are ambiguous or borderline. Further studies including larger numbers of patients are necessary to establish MMP-2 as a routine marker for tumor invasion and progression.