Bougie-guided insertion of the ProSeal™ laryngeal mask airway has higher first attempt success rate than the digital technique in children

BACKGROUND

We tested the hypothesis that bougie-guided insertion of the ProSeal laryngeal mask airway (ProSeal LMA) has higher success rate than the digital technique in children.

METHODS

One hundred and twenty children (ASA I-II, aged 1-16 yr) were randomly allocated for ProSeal LMA insertion using the digital or bougie-guided technique. The digital technique was performed according to the manufacturer's instructions. The bougie-guided technique involved priming the drain tube with a bougie, placing the bougie in the oesophagus under direct vision and railroading the ProSeal LMA into position. Unblinded data were collected about ease of insertion (number of attempts and time taken to provide an effective airway), efficacy of seal, ease of gastric tube placement, haemodynamic responses and blood staining. Blinded data were collected about postoperative airway morbidity.

RESULTS

The first attempt success rate was higher for the bougie-guided technique (59/60 vs 52/60, P=0.015), but effective airway time was longer (37 vs 32 s, P<0.001). There were no differences in efficacy of seal, ease of gastric tube placement, haemodynamic responses, blood staining or postoperative airway morbidity.

CONCLUSION

We conclude that bougie-guided insertion of the ProSeal LMA has a higher first attempt success rate than the digital technique in children.

Cadmium hyperaccumulation and reproductive traits in natural Thlaspi caerulescens populations

During the last decade, the metal hyperaccumulating plants have attracted considerable attention because of their potential use in decontamination of heavy metal contaminated soils. However, in most species, little is known regarding the function, the ecological and the evolutionary significances of hyperaccumulation. In our study, we investigated the parameters influencing the Cd concentration in plants as well as the biological implications of Cd hyperaccumulation in nine natural populations of Thlaspi caerulescens. First, we showed that Cd concentration in the plant was positively correlated with plant Zn, Fe, and Cu concentrations. This suggested that the physiological and/or molecular mechanisms for uptake, transport and/or accumulation of these four heavy metals interact with each other. Second, we specified a measure of Cd hyperaccumulation capacity by populations and showed that T. caerulescens plants originating from populations with high Cd hyperaccumulation capacity had better growth, by developing more and bigger leaves, taller stems, and produced more fruits and heavier seeds. These results suggest a tolerance/disposal role of Cd hyperaccumulation in this species.

Maskenbeatmung als Rückzugsstrategie zur endotrachealen Intubation

The goal of ventilation in an unprotected airway is to optimize oxygenation and carbon dioxide elimination of the patient. This can be achieved with techniques such as mouth-to-mouth ventilation, but preferably with bag-valve-mask ventilation. Securing the airway with an endotracheal tube is the gold standard, but excellent success in emergency airway management depends on initial training, retraining, and actual frequency of a given procedure in the routine. "Patients do not die from failure to intubate; they die from failure to stop trying to intubate or from undiagnosed oesophageal intubation" (Scott 1986). Therefore, adequate face mask ventilation has absolute priority in airway management by an unexperienced rescuer. During ventilation of an unprotected airway, stomach inflation and subsequent severe complications may result. Careful ventilation can be performed with low inspiratory pressure and flow, and subsequently with a low tidal volume at a high inspiratory fraction of oxygen. This could be a strategy to achieve more patient safety.

Primary Burkitt lymphoma of the uterine corpus

This study reports the first well-documented case of sporadic Burkitt lymphoma arising in and confined to the uterine corpus in a 40-year-old woman who presented with vaginal bleeding. Endometrial curettings showed a diffuse infiltrate of medium sized lymphocytes with the characteristic morphologic and immunophenotypic features of Burkitt lymphoma. Fluorescence in-situ hybridization demonstrated the t(8;14)(q24;q32) translocation. There was no evidence of extra-uterine disease and the patient is alive without disease 10 months after hysterectomy and chemotherapy. This report demonstrates that Burkitt lymphoma can present as isolated, organ confined disease at unusual sites and with protean symptoms.

Pressure support ventilation with the ProSeal laryngeal mask airway. A comparison of sevoflurane, isoflurane and propofol

BACKGROUND AND OBJECTIVE

There are no data about the influence of anaesthetics on cardiovascular variables during pressure support ventilation of the lungs through the laryngeal mask airway. We compared propofol, sevoflurane and isoflurane for maintenance of anaesthesia with the ProSeal laryngeal mask airway during pressure support ventilation.

METHODS

Sixty healthy adults undergoing peripheral musculo-skeletal surgery were randomized for maintenance with sevoflurane end-tidal 2%, isoflurane end-tidal 1.1% or propofol 6 mg kg(-1) h(-1) in oxygen 33% and air. Pressure support ventilation comprised positive end-expiratory pressure set at 5 cmH2O, and pressure support set 5 cmH2O above positive end-expiratory pressure. Pressure support was initiated when inspiration produced a 2 cmH2O reduction in airway pressure. A blinded observer recorded cardiorespiratory variables (heart rate, mean blood pressure, oxygen saturation, airway occlusion pressure, respiratory rate, expired tidal volume, expired minute volume and end-tidal CO2), adverse events and emergence times.

RESULTS

Respiratory rate and minute volume were 10-21% lower, and end-tidal CO2 6-11% higher with the propofol group compared with the sevoflurane or isoflurane groups, but otherwise cardiorespiratory variables were similar among groups. No adverse events occurred in any group. Emergence times were longer with the propofol group compared with the sevoflurane or isoflurane groups (10 vs. 7 vs. 7 min).

CONCLUSION

Lung ventilation is less effective and emergence times are longer with propofol than sevoflurane or isoflurane for maintenance of anaesthesia during pressure support ventilation with the ProSeal laryngeal mask airway. However, these differences are small and of doubtful clinical importance.

Right spatial neglect after left hemisphere stroke: qualitative and quantitative study

OBJECTIVES

Comparatively little research has been conducted on right neglect after left brain damage. The authors sought to assess contralateral neglect in subacute left hemisphere stroke patients using a comprehensive test battery validated in a large control group after right hemisphere stroke.

METHODS

Seventy-eight left hemisphere stroke patients were assessed. The test battery included a preliminary assessment of anosognosia and visual extinction, a clinical assessment of gaze orientation and personal neglect, and paper-and-pencil tests of spatial neglect in the peripersonal space. Only nonverbal tests were used.

RESULTS

Drawing and cancellation tasks revealed neglect in 10 to 13% of patients. The combined battery was more sensitive than any single test alone. A total of 43.5% of patients showed some degree of neglect on at least one measure. Anatomic analyses showed that neglect was more common and severe when the posterior association cortex was damaged.

CONCLUSIONS

The frequency of occurrence of right neglect was, as expected, much lower than that reported in a study using the same assessment battery in right brain damage stroke patients. Nevertheless, neglect was found in a substantial proportion of patients at a subacute stage, suggesting that it should be considered in the rehabilitation planning of left brain damage stroke patients.

Lingual nerve injury associated with the ProSeal laryngeal mask airway: a case report and review of the literature

We present a case of lingual nerve injury that was associated with use of the ProSeal laryngeal mask airway during shoulder replacement in a 61-yr-old male. We also review other cases of cranial nerve injury, most of which were associated with use of the classic laryngeal mask airway. In principle, the frequency of cranial nerve injuries can be reduced by avoiding insertion trauma, using appropriate sizes, minimizing cuff volume, and early identification and correction of malposition.

Repeat autoclaving does not remove protein deposits from the classic laryngeal mask airway

INTRODUCTION

We tested the hypothesis that repeated autoclaving removes protein deposits from the classic laryngeal mask airway (LMA).

METHODS

Twenty previously used LMAs were hand washed, machine washed, dried, autoclaved and randomly allocated into four equal-sized groups for repeat autoclaving on 0 (control), 1, 2 and 3 occasions. After the final autoclave cycle, the LMAs were immersed in a protein-staining solution, rinsed, dried and a high-resolution digital image taken of the dorsal and ventral surfaces. The severity of staining was scored by two blinded observers.

RESULTS

All LMAs were stained. There was no reduction in staining with repeat autoclaving.

CONCLUSIONS

Repeat autoclaving does not remove protein deposits from the LMA.

Incidence of lower thoracic ligamentum flavum midline gaps † †Presented in abstract form at the IARS 78th Clinical and Scientific Congress, Tampa Bay, Florida, USA, 2004

BACKGROUND

Lower thoracic epidural anaesthesia and analgesia (EDA) has gained increasing importance in perioperative pain therapy. The loss-of-resistance technique used to identify the epidural space is thought to rely on the penetration of the ligamentum flavum. Investigations at the cervical and lumbar regions have demonstrated that the ligamentum flavum frequently exhibits incomplete fusion at different vertebral levels. Therefore, the aim of this study was to directly investigate the incidence of lower thoracic ligamentum flavum midline gaps in embalmed cadavers.

METHODS

Vertebral column specimens were obtained from 47 human cadavers. Ligamentum flavum midline gaps were recorded between the vertebral levels T6 and L1.

RESULTS

The incidence of midline gaps/number of viable specimens at the following levels was: T6-7: 2/45 (4.4%), T7-8: 1/47 (2.1%), T8-9: 2/45 (4.4%), T9-10: 7/39 (17.9%), T10-11: 12/34 (35.2%), T11-12: 10/35 (28.5%), T12/L1: 6/38 (15.8%).

CONCLUSIONS

In the present study we have determined the frequency of lower thoracic ligamentum flavum midline gaps. Gaps are less frequent than at cervical levels, but more frequent than at lumbar levels. Peak incidence was found in the region between T10 and T12. Using a strict midline approach, one cannot therefore rely on the ligamentum flavum to impede entering the epidural space in all patients.

Bone marrow changes in chronic myelogenous leukaemia after long-term treatment with the tyrosine kinase inhibitor STI571: an immunohistochemical study on 75 patients

AIMS

To carry out an immunohistochemical study on bone marrow (BM) biopsy specimens in 75 patients with chronic myelogenous leukaemia (CML) on long-term STI571 therapy.

METHODS AND RESULTS

Sequential BM specimens taken at intervals of 21 +/- 6 months were investigated by enzyme- and immunohistochemistry including proliferating cell nuclear antigen and apoptosis. Evaluation was performed either by semiquantitative scoring or by morphometry (CD61+ megakaryopoiesis). In 41 patients with chronic phase CML, treatment resulted in a significant decrease in cellularity and neutrophil granulopoiesis contrasting with an accumulation of erythroid precursor cells. Morphometry showed a reduction of abnormal micromegakaryocytes consistent with normalization. Regression of myelofibrosis was identified in eight of 15 patients, whereas progression occurred in 17 patients; mostly in those with acceleration and blastic crisis. The increased post-treatment incidence of reactive lymphoid nodules was remarkable. Myeloblasts, CD34+ progenitors and immature myelomonocytic cells initially decreased, but recurred in 14 patients who later developed a relapse. STI571 exerted an inhibitory effect on cell proliferation associated with enhanced apoptosis in responding patients.

CONCLUSION

Long-term treatment with STI571 exerts pronounced changes on BM histopathology that not only involve haematopoiesis and stromal constituents, but also proliferation and apoptosis.

Verkürzte Inspirationszeit während der Beatmung eines ungeschützten Atemweges

BACKGROUND

In an unprotected airway during cardiopulmonary resuscitation, two ventilations with an inspiratory time of 2 s after 15 chest compressions are recommended. Therefore, approximately 30% of the resuscitation attempt is spent on ventilation. Since survival rates did not decrease sharply when minute ventilation levels were relatively low, and uninterrupted chest compressions with a constant rate of approximately 100/min have been shown to be lifesaving, it may be beneficial to decrease the time spent on ventilation and instead, increase the time for chest compressions.

METHODS

In an established bench model of a simulated, unprotected airway with increased airway resistance, we evaluated if inspiratory time can be decreased from 2 to 1 s at different lower oesophageal sphincter pressure (LOSP) levels during ventilation with a bag-valve-mask device.

RESULTS

An inspiratory time of 2 vs. 1 s resulted in significantly lower peak airway pressure, while lung tidal volume was significantly higher at an inspiratory time of 2 s and a LOSP of 5 cm H(2)O (480+/-20 vs. 380+/-30 ml) and 10 cm H(2)O (630+/-50 vs. 440+/-20 ml) and significantly lower at a LOSP of 15 cm H(2)O (470+/-70 vs. 540+/-20 ml). While neither ventilation strategy produced stomach inflation at 20 cm H(2)O LOSP, 1 vs. 2 s inspiratory time produced significantly higher stomach inflation at 15 cm H(2)O LOSP (8+/-11 vs. 0 ml) and significantly lower stomach inflation at a LOSP of 5 cm H(2)O (359+/-31 vs. 375+/-29 ml) and 10 cm H(2)O (28+/-13 vs. 36+/-12 ml) per breath.

CONCLUSION

In this model of a simulated, unprotected airway, a reduction of inspiratory time from 2 to 1 s resulted in a significant increase of peak airway pressure, while lung tidal volumes and stomach inflation volumes were statistically different but clinically comparable.

Pressure Support Ventilation Versus Continuous Positive Airway Pressure Ventilation with the ProSeal??? Laryngeal Mask Airway: A Randomized Crossover Study of Anesthetized Pediatric Patients

Continuous positive airway pressure (CPAP) and pressure support ventilation (PSV) improve gas exchange in adults, but there are little published data regarding children. We compared the efficacy of PSV with CPAP in anesthetized children managed with the ProSeal laryngeal mask airway. Patients were randomized into two equal-sized crossover groups and data were collected before surgery. In Group 1, patients underwent CPAP, PSV, and CPAP in sequence. In Group 2, patients underwent PSV, CPAP, and PSV in sequence. PSV comprised positive end-expiratory pressure set at 3 cm H(2)O and inspiratory pressure support set at 10 cm H(2)O above positive end-expiratory pressure. CPAP was set at 3 cm H(2)O. Each ventilatory mode was maintained for 5 min. The following data were recorded at each ventilatory mode: ETco(2), Spo(2), expired tidal volume, peak airway pressure, work of breathing patient (WOB), delta esophageal pressure, pressure time product, respiratory drive, inspiratory time fraction, respiratory rate, noninvasive mean arterial blood pressure, and heart rate. In Group 1, measurements for CPAP were similar before and after PSV. In Group 2, measurements for PSV were similar before and after CPAP. When compared with CPAP, PSV had lower ETco(2) (46 +/- 6 versus 52 +/- 7 mm Hg; P < 0.001), slower respiratory rate (24 +/- 6 versus 30 +/- 6 min(-1); P < 0.001), lower WOB (0.54 +/- 0.54 versus 0.95 +/- 0.72 JL(-1); P < 0.05), lower pressure time product (94 +/- 88 versus 150 +/- 90 cm H(2)O s(-1)min(-1); P < 0.001), lower delta esophageal pressure (10.6 +/- 7.4 versus 14.1 +/- 8.9 cm H(2)O; P < 0.05), lower inspiratory time fraction (29% +/- 3% versus 34% +/- 5%; P < 0.001), and higher expired tidal volume (179 +/- 50 versus 129 +/- 44 mL; P < 0.001). There were no differences in Spo(2), respiratory drive, mean arterial blood pressure, and heart rate. We conclude that PSV improves gas exchange and reduces WOB during ProSeal laryngeal mask airway anesthesia compared with CPAP in ASA physical status I children aged 1-7 yr.

Lipoprotein processing is required for virulence of Mycobacterium tuberculosis

Lipoproteins are a subgroup of secreted bacterial proteins characterized by a lipidated N-terminus, processing of which is mediated by the consecutive activity of prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein signal peptidase (LspA). The study of LspA function has been limited mainly to non-pathogenic microorganisms. To study a potential role for LspA in the pathogenesis of bacterial infections, we have disrupted lspA by allelic replacement in Mycobacterium tuberculosis, one of the world's most devastating pathogens. Despite the presence of an impermeable lipid outer layer, it was found that LspA was dispensable for growth under in vitro culture conditions. In contrast, the mutant was markedly attenuated in virulence models of tuberculosis. Our findings establish lipoprotein metabolism as a major virulence determinant of tuberculosis and define a role for lipoprotein processing in bacterial pathogenesis. In addition, these results hint at a promising new target for therapeutic intervention, as a highly specific inhibitor of bacterial lipoprotein signal peptidases is available.

X-ray emission spectroscopy of (23×23)R30°CO/Ru(0001): Comparison to c(2×2)CO/Ni(100) and c(2×2)CO/Cu(100)

The atom specific electronic structure of (2 square root of 3 x 2 square root of 3)R30 degrees CO on hcp Ru(0001) has been determined with resonantly excited x-ray emission spectroscopy. We find that the general features of the local adsorbate electronic structure are similar to the situation of CO adsorbed on the fcc metals Ni(100) and Cu(100). The interpretation of the surface chemical bond of (2 square root of 3 x 2 square root of 3)R30 degrees CO/Ru(0001) based on the direct application of the local, allylic model from on-top adsorption on the fcc(100) surfaces Ni(100) and Cu(100) explains many aspects of the surface chemical bond. However, also nonlocal contributions like adsorbate-adsorbate interaction and the deviation from upright on-top adsorption on the Ru(0001) surface influence observables like the heat of adsorption and the Me-CO bond strength.

Aspiration and the laryngeal mask airway: three cases and a review of the literature

The primary limitation of the laryngeal mask airway (LMA) is that it does not reliably protect the lungs from regurgitated stomach content. We describe three cases of aspiration associated with the LMA, including the first brain injury, the first death, and the first associated with the intubating LMA, and review the 20 specific case reports of aspiration associated with the LMA that we were able to find described in the literature.

Unintentional arterial puncture during cephalic vein cannulation: case report and anatomical study †

BACKGROUND

The cephalic antebrachial vein is often used for venous access. However, superficial radial arteries of the forearm are known and unintentional arterial puncture can result from attempts to cannulate the lateral veins of the arm.

METHODS

Accidental puncture of a superficial radial artery during peripheral venous cannulation prompted us to study the anatomy of 26 specimens and to assess the relationship between the radial artery and the cephalic vein in the forearm.

RESULTS

In two cases, we found accessory branches of the radial artery close to the cephalic forearm vein. Venous cannulation at the lateral wrist carries a small risk of arterial puncture if arterial anomalies are present.

CONCLUSIONS

If venous cannulation is attempted at the radial side of the wrist, palpation for pulsation should reduce the danger of arterial puncture.

Accuracy in estimating the correct intervertebral space level during lumbar, thoracic and cervical epidural anaesthesia

BACKGROUND

Even in the absence of factors concealing anatomical landmarks, high failure rates in correctly determining a given lumbar interspace have been reported.

METHODS

Therefore, it was the aim of the present study to compare the assessed and factual level (determined by computed tomography) of epidural puncture in attending a regional anaesthesia cadaver workshop. Eighty-two anaesthetists performed 117 punctures.

RESULTS

Vertebral interspaces between T8-L4 were correctly identified more often than those between C3-T5 (P < 0.05). Identification of an arbitrarily chosen vertebral interspace was excellent in both the cervical/high thoracic and thoracic/lumbar regions.

CONCLUSION

As previously conjectured only for the lumbar region, we could confirm the tendency of anaesthetists to perform neuraxial puncture more cranially than expected also for the thoracic and cervical regions. The large majority of punctures (93.7%) was performed within one interspace of the predicted level.

Cytokines in the seronegative spondyloarthropathies and their modification by TNF blockade: a brief report and literature review

Rheumatoid arthritis (RA) is a disease well characterised by proinflammatory cytokine secretion (particularly tumour necrosis factor, interferon gamma, interleukin (IL) 1, and IL6). Less has been reported about the cytokine profiling in the spondyloarthropathies (SpA). Several trials suggest that, similar to RA, proinflammatory cytokines are globally expressed in the SpA. However, other studies report a down regulation of these cytokines in the SpA, with a relative anti-inflammatory polarisation (featuring increases in IL4, IL5, and IL10). This review summarises current published reports and the variation in cytokine data in the SpA. Additionally, results of cytokine profiles in patients with ankylosing spondylitis before and after treatment with etanercept are reported.

An In vitro Study on Spontaneous Cervical Contractility in the Cow During Oestrus and Diestrus

Cervical smooth muscle specimens were collected from slaughtered cows in oestrus and diestrus. Longitudinal and circular specimens were mounted in organ baths and after equilibration time and 2 g pre-load, their physiologic isometric contractility was recorded for 2.5 h. Area under the curve (AUC), maximal amplitude (Amax), mean amplitude (Amen) and minimal amplitude (Amin) were studied. Differences between cycle phases, between muscle layers and over the recorded time periods were statistically evaluated using linear mixed-effect models. In the cow, physiologic contractility of the cervix decreased significantly over time for all variables evaluated (time as covariate on a continuous scale). Furthermore, for Amax, there was a tendency for an influence of muscle layer (longitudinal > circular). Contractility was not influenced by cycle phases.

Efficacy and safety of DALI LDL-apheresis at high blood flow rates: A prospective multicenter study

Direct adsorption of lipids (DALI) is the first LDL-apheresis method compatible with whole blood. Usually, the blood flow rate is adjusted at 60-80 ml/min, which results in session times of about 2 hr. The present study was performed to test the safety and efficacy of low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) [Lp(a)] removal by DALI at high blood flow rates in order to reduce treatment time. Thirteen chronic DALI patients in seven centers suffering from hypercholesterolemia (LDL-C 162 +/- 42 mg/dl at baseline) and coronary artery disease were treated on a weekly or biweekly basis by DALI apheresis. The blood flow rate QB was held constant for at least two sessions, respectively, and was increased from 60 to 80, 120, 160, 200, and 240 ml/min. All patients had pre-existing av-fistulas. The anticoagulation was performed by a heparin bolus plus ACD-A at a ratio of citrate:blood ranging from 1:20 to 1:90. Clinically, the sessions were well tolerated and only 26/201 sessions (12%) of the treatments were fraught with minor adverse events. Acute LDL-C reductions (derived from LDL-C levels determined by lipoprotein electrophoresis) averaged 72/66/60/53/50/48% for QB=60/80/120/160/200/240 ml/min. Lp(a) reductions were 68/67/62/60/58/56%, whereas HDL-C losses were < or =10%. Routine blood chemistries and blood cell counts remained in the normal range. Treatment times averaged 142/83/45 min at Qb=60/120/240 ml/min. On average, DALI LDL-apheresis could be performed safely and effectively at high blood flow rates up to at least 120 ml/min in patients with good blood access, which significantly reduced treatment time from 142 to 83 min (-42%).

Searching for the exercise factor: is IL-6 a candidate?

For years the search for the stimulus that initiates and maintains the change of excitability or sensibility of the regulating centers in exercise has been progressing. For lack of more precise knowledge, it has been called the 'work stimulus', 'the work factor' or 'the exercise factor'. In other terms, one big challenge for muscle and exercise physiologists has been to determine how muscles signal to central and peripheral organs. Here we discuss the possibility that interleukin-6 (IL-6) could mediate some of the health beneficial effects of exercise. In resting muscle, the IL-6 gene is silent, but it is rapidly activated by contractions. The transcription rate is very fast and the fold changes of IL-6 mRNA is marked. IL-6 is released from working muscles into the circulation in high amounts. The IL-6 production is modulated by the glycogen content in muscles, and IL-6 thus works as an energy sensor. IL-6 exerts its effect on adipose tissue, inducing lipolysis and gene transcription in abdominal subcutaneous fat and increases whole body lipid oxidation. Furthermore, IL-6 inhibits low-grade TNF-alpha-production and may thereby inhibit TNF-alpha-induced insulin resistance and atherosclerosis development. We propose that IL-6 and other cytokines, which are produced and released by skeletal muscles, exerting their effects in other organs of the body, should be named 'myokines'.

A comparison of the ProSeal and classic laryngeal mask airways for airway management by inexperienced personnel after manikin-only training

We compared the ProSeal (PLMA) and Classic (LMA) laryngeal mask airway for airway management by inexperienced personnel. Nine nurses from the post-anaesthesia care unit, with no prior experience of LMA or PLMA insertion, were observed inserting the LMA and PLMA in 60 ASA 1 to 2 anaesthetized, paralyzed adults following manikin-only training. The time to achieve an effective airway (2 consecutive expired tidal volumes (6 ml/kg; maximum 2 minutes allowed), the number of insertion attempts and the reasons for failure (inability to insert into pharynx or inadequate ventilation) were determined by analysis of digital video recordings. The first attempt success rate (LMA, 85%; PLMA, 83%), overall success rate (LMA, 88%; PLMA, 90%) and effective airway time (LMA, 39 +/- 13 s; PLMA, 43 +/- 19 s) were similar. Failure was from an inability to insert into the pharynx in five with the LMA and three with the PLMA, and inadequate ventilation with two from the LMA and three from the PLMA. Effective airway time and the number of failures were similar for the first and second device. Failure of both devices occurred in four patients. We conclude that airway management in anaesthetized, paralyzed adults is equally successful for the LMA and PLMA by inexperienced personnel following manikin-only training. The PLMA is worthy of consideration as a tool for emergency airway management by inexperienced personnel.

Pharyngeal mucosal pressures with the laryngeal tube airway versus ProSeal laryngeal mask airway

We tested the hypothesis that mucosal pressures are higher for the laryngeal tube airway trade mark than the ProSeal laryngeal mask airway. Fifteen fresh cadavers were studied. Microchip pressure sensors were attached to the laryngeal tube airway and ProSeal laryngeal mask airway at four similar anatomical locations (base of tongue, lateral pharynx, posterior pharynx and posterior hypopharynx) and three dissimilar locations (laryngeal tube airway trade mark, anterior and lateral hypopharynx; ProSeal laryngeal mask airway, pyriform fossa). The cuff volume (laryngeal tube airway, < or = 140 ml; ProSeal laryngeal mask airway, < or = 30 ml) was adjusted until the oropharyngeal leak pressure was 15 cm H2O and the mucosal pressures recorded. This was repeated at an oropharyngeal leak pressure of 20, 25 and 30 cm H2O. Mucosal pressures in the lateral pharynx were always similar. Mucosal pressures at the base of tongue and posterior pharynx were similar for the laryngeal tube airway and ProSeal laryngeal mask airway at 15 and 20 cm H2O, but were higher for the laryngeal tube airway at 25 cm H2O at 30 cm H2O. Mucosal pressures in the posterior hypopharynx were always higher for the laryngeal tube airway (all: p < 0.03). Mean mucosal pressures for the laryngeal tube airway ranged from 8-31, 2-13 and 15-41 cm H2O for the base of tongue, lateral pharynx and posterior pharynx (proximal cuff) respectively and 3-7, 3-7 and 7-18 cm H2O for the anterior, lateral and posterior hypopharynx (distal cuff) respectively. Mean mucosal pressures for the ProSeal laryngeal mask airway ranged from 6-23, 3-10, 8-25, 6-17 and 2-8 cm H2O for the base of tongue, lateral pharynx, posterior pharynx, pyriform fossa and posterior hypopharynx respectively. We conclude that mucosal pressures are higher for the laryngeal tube airway, particularly when oropharyngeal leak pressure greater than 25 cm H2O. This suggests that mucosal ischemic injury will be more common with the LTA than the PLMA.

Feasibility, accuracy and optimal location for oesophageal core temperature measurements using the ProSeal laryngeal mask airway drain tube

We determined the feasibility, accuracy and optimal location of oesophageal core temperature measurements using the ProSeal laryngeal mask airway drain tube. Thirty normothermic anaesthetized ventilated adults (ASA 1 to 2, aged 18 to 80 years) were studied. Temperatures were recorded using a thermistor at six different locations (middle of drain tube and at 0 to 20 cm distal to the drain tube in 5 cm increments) and compared to nasopharyngeal (thermistor) and aural (infrared tympanic thermometer) reference core temperatures. The temperature probe was successfully inserted into the oesophagus in all patients at the first attempt. Oesophageal temperature increased with depth from 0 to 5 cm (35.2 v 35.9, P < 0.0001) and 5 to 10 cm (35.9 v 36.3, P < 0.01), but was unchanged from 10 to 15 cm (36.3 v 36.6) and 15 to 20 cm (36.6 v 36.7). Aural temperature was higher than nasopharyngeal temperature (36.8 v 36.0, P < 0.0001). Aural temperature was 0.89 to 1.59 degrees C higher than the oesophagus at 0 to 5 cm and 0.21 to 0.30 degree C higher than the oesophagus at 15 to 20 cm. Nasopharyngeal temperature was 0.06 to 0.76 degree C higher than the oesophagus at 0 to 5 cm and 0.62 to 0.84 degree C lower than the oesophagus at 15 to 20 cm. The lowest temperature was in the mid-point of the drain tube (34.7). We conclude that oesophageal core temperature measurement is feasible and accurate using the ProSeal laryngeal mask airway. The optimal location for the temperature probe is at 15 to 20 cm.

[Comparison of algorithms for management of the difficult airway]

Management of the difficult airway and maintenance of the oxygenation are the most important tasks of the anaesthetist. Respiratory problems are still the most important single cause for anaesthesia-related accidents with poor outcome. Algorithms are step-wise procedures developed from a great number of recommendations and are well suited to automation and training procedures. There is strong agreement among consultants that specific strategies lead to improved outcome, although, strictly speaking the degree of benefit on airway management cannot be clearly determined. Several anaesthesia societies, including the American Society of Anesthesiology,have developed their own algorithms for management of the difficult airway. The comparison of published algorithms shows that the management of the anticipated difficult airway has to be performed in the awake patient and fiberoptic intubation is a crucial part of that procedure. There are different techniques (different blades, guide wire, laryngeal mask, fiber optics) for the management of the unanticipated difficult airway. The laryngeal mask, transtracheal access and the Combitube are recommended for the management of the cannot intubate, cannot ventilate situation. More important than the questions which algorithm, which technique and which instruments should be used,is that each department has and practices its own algorithm. This strongly depends on local circumstances and personal preferences. Daily practice is the condition for the successful use in an emergency situation. The management is easier if one uses a simple algorithm and as few instruments as possible.

Stability of the LMA-ProSeal and standard laryngeal mask airway in different head and neck positions: a randomized crossover study

BACKGROUND AND OBJECTIVE

The LMA-ProSeal laryngeal mask airway is a new laryngeal mask airway with a modified cuff and drainage tube. We compared oropharyngeal leak pressure, intracuff pressure and anatomical position (assessed fibreoptically) for the Size 5 LMA-ProSeal laryngeal mask airway and the classic laryngeal mask airway in different head-neck positions and using different intracuff inflation volumes.

METHODS

Thirty paralysed anaesthetized adult male patients were studied. The LMA-ProSeal laryngeal mask airway and the classic laryngeal mask airway were inserted into each patient in random order. The oropharyngeal leak pressure, intracuff pressure, and anatomical position of the airway tube and drainage tube (LMA-ProSeal laryngeal mask airway only) were documented in four head and neck positions (neutral first, then flexion, extension and rotation in random order), and at 0-40 mL cuff volumes in the neutral position in 10 mL increments.

RESULTS

Compared with the neutral position, the oropharyngeal leak pressure for both the LMA-ProSeal laryngeal mask airway and the classic laryngeal mask airway was higher in flexion and rotation (all P < or = 0.02), but lower in extension (all P < or = 0.01). Changes in head-neck position did not alter the anatomical position of the airway tube or the drainage tube. The oropharyngeal leak pressure was always higher for the LMA-ProSeal laryngeal mask airway (all P < or = 0.005) and anatomical position better for the classic laryngeal mask airway (all P < or = 0.04).

CONCLUSIONS

The anatomical position of the LMA-ProSeal and the classic laryngeal mask airway is stable in different head-neck positions, but head-neck flexion and rotation are associated with an increase, and head-neck extension a decrease, in oropharyngeal leak pressure and intracuff pressure. The Size 5 LMA-ProSeal laryngeal mask airway is capable of forming a more effective seal than the Size 5 classic laryngeal mask airway in males.

Gum-elastic bougie-guided insertion of the ProSeal laryngeal mask airway: a new technique

We determined the success rates, cardiovascular responses and airway morbidity for gum-elastic bougie-guided insertion of the ProSeal laryngeal mask airway. One hundred anaesthetized, non-paralyzed adults (ASA 1-2 aged 18 to 80 years) were studied. The ProSeal LMA drainage tube was primed with a well-lubricated 16 French gauge gum-elastic bougie with the curved end proximal and the straight end protruding 30 cm beyond the drainage tube tip. The straight end of the gum-elastic bougie was inserted into the oesophagus under laryngoscopic guidance, the laryngoscope removed and the ProSeal LMA inserted using the standard insertion technique and the gum-elastic bougie as a guide. The following variables were recorded: ease of insertion, oropharyngeal leak pressure, ventilatory capability, ease of gastric tube insertion, blood staining on the bougie or LMA at removal, and postoperative airway morbidity. Haemodynamic data were recorded immediately pre-insertion and every minute for five minutes after insertion. Gum-elastic bougie and ProSeal LMA insertion was successful at the first attempt in all patients within 50 seconds. There were no significant increases in heart rate or blood pressure. Oropharyngeal leak pressure was 33 (17-40) cmH2O and ventilation was possible without leak in all patients at 9.5 ml x kg(-1) tidal volume. There were no drainage tube or gastric air leaks. Gastric tube insertion was successful at the first attempt in all patients. Blood staining at removal was not detected on the gum-elastic bougie, but was detected in 3% of ProSeal LMAs. The incidence of sore throat, dysphagia and dysarthria was 21%, 9% and 1% respectively. We conclude that gum-elastic bougie-guided insertion of the ProSeal LMA has a high success rate and is associated with minimal haemodynamic change and a low incidence of trauma.