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PubMedDate not supplied

[The laryngeal mask--news in orthopedic anesthesia].

The laryngeal mask airway (LMA) was first used at the Department of Orthopedics, School of Medicine, University of Zagreb on May 8, 1991. Two hundred and three patients were undergoing elective orthopedic surgery during the first year of the LMA use. A size-3 mask was used for women and children weighing over 25 kg (55 lbs) and a size-4 mask for men. Research has been undertaken in 12 patients aged between 30-73 years scheduled for total hip replacement. Blood pressure, heart rate and hemoglobin oxygen saturation were continuously monitored with a noninvasive method. No signs of cardiovascular disorders were noticed 1-min before and 3-min after insertion. Only 2 (16.6%) patients, who suffered no complications, had ventilating pressure higher than 20 cm H2O. The LMA proved to be very useful in anesthesia where endotracheal intubation was difficult or almost impossible. Of 12 examinees, 3 with severe rheumatoid arthritis and 2 with ankylosing spondylitis were successfully anesthetized with the LMA. Awakening from anesthesia was very pleasant. There were no serious complications in terms of laryngo- or bronchospasm, aspiration or insufflation of the stomach. The LMA has been found to be very helpful in solving problems of anesthesia in orthopedic patients. A set of laryngeal mask airways should be an integral part of every anesthetic equipment.

Adolescent↗
PubMed1993

[Importance of surgical masks for peroperative asepsis].

For more than 70 years, the surgical mask has been used under operations as part of the maintenance of aseptic conditions in the operational field. Experiments with models and investigations of sources of infection carried out over the past 20 years have shown, however, that the bacterial flora of the upper respiratory tract do not contribute to airborne contamination of the surgical wound, but that persons who are situated directly beside the field may contaminate the wound directly by droplets released by speech, sneezing or coughing. Over the last ten years the usefulness of the surgical mask has been disputed several times, and a few controlled clinical trials have been able to confirm any benefits associated with use of surgical masks. There is therefore no reason from the point of view of preventing infection to maintain a general requirement for the use of surgical masks by others than those persons who may be situated within an arm's length of the operational field or instrument table.

Asepsis↗
PubMed1993

A new nasal mask for nocturnal home ventilation in chronic neuromuscular disorders.

A new nasal mask for nocturnal, intermittent positive pressure ventilation was used by patients with symptomatic sleep hypoventilation due to chronic neuromuscular disorders. The custom-fabricated mask is cast in visible light curing acrylic from a plaster model. Air is delivered through plastic tubes cast in the mask. The treatment was introduced through close cooperation between a physiotherapist and a technician. Evaluation was performed after 4-34 months' regular use. The mask was well tolerated. All patients reported comfortable sleep and symptom relief. The effectiveness was confirmed by whole-night measurements of oxygen saturation and end-tidal carbon dioxide.

Adult↗
PubMedDate not supplied

[Energy relationships in the human cutaneous system under conditions of single, residual and reverse masking].

Studies were carried out by electron-mechanic adequatometer permitting to obtain two shifted in time air stimuli. According to the curves of pressure duration thershold energies were determined theoretically for the stimuli of various durations; energy-duration curves were plotted. The adequatometric analysis of the curves made it possible to determine: 1. qualitative and quantitative similarity of energetic regularities of simultaneous residual and reverse masking; 2. the masking interval value during the residual masking; 3 critical time of discovering the threshold stimulus during the reverse masking.

Biomechanical Phenomena↗
PubMed1995

Relation between backward masking deficits and smooth pursuit dysfunction in schizophrenia?

Backward masking deficit and smooth pursuit dysfunction are cognitive, information processing markers associated with schizophrenia. In schizophrenia, backward masking is typically manifest as a longer interstimulus interval over which a mask is still effective in interfering with the processing of a preceding target. Smooth pursuit dysfunction is characterized by saccadic smooth pursuit, saccadic intrusions, and low-gain pursuit. Although the natures of the two markers relative to schizophrenia are somewhat different (e.g., smooth pursuit dysfunction is a genetic marker; backward masking is associated more strongly with negative symptoms, poor prognosis schizophrenia), information processing theory indicates a possible neurocognitive relation between the two.

Eye Movements↗
PubMedDate not supplied

[Mechanical ventilation with laryngeal mask in anesthesia. Personal experience].

AIM: The aim of the study was to evaluate the following: the difficulty of inserting a laryngeal mask without the use of muscle relaxants and laryngoscopy; the incidence of possible intraoperative cardiocirculatory and respiratory alterations during the association of laryngeal mask and mechanical ventilation; local intra and postoperative complications due to their combined use. EXPERIMENTAL PROTOCOL: Open, non-random study. SETTING: Provincial hospital. PATIENTS EXAMINED: 118 patients of both sexes, of various ages, and from a number of surgical fields. OPERATIONS: General anaesthesia performed using mechanical ventilation and laryngeal mask. RESULTS: There was no difficulty in positioning the laryngeal mask without muscle relaxants and laryngoscopy; no alterations were observed in the hemodynamic and respiratory parameters monitored; intra and postoperative local complications were frequently present in a high percentage of cases, consisting respectively in increased mucopharyngeal secretion and pharyngeal irritation and dysarthria. Whereas the former did not represent a serious clinical problem, the latter proved more troublesome for patients following surgery.

Adult↗
PubMed1997

Haemodynamic response to tracheal intubation or laryngeal mask insertion in hypertensive patients.

The haemodynamic response to laryngeal mask insertion and tracheal intubation was studied in 27 hypertensive patients who underwent elective ophthalmic surgery. Both groups received alfentanil 15 micrograms/kg, thiopentone 3-4 mg/kg and vecuronium 0.1 mg/kg and were ventilated with oxygen, nitrous oxide and isoflurane for 3 minutes prior to laryngeal mask insertion or tracheal intubation. Blood pressure and heart rate decreased equally in both groups after induction of anaesthesia. Haemodynamic variables increased after tracheal intubation but were unchanged after laryngeal mask insertion (P < 0.05 for intergroup differences). Heart rate, but not blood pressure, increased above baseline levels in the tracheal intubation group. The anaesthetic technique used blunted the haemodynamic response to tracheal intubation, but completely blocked the response to laryngeal mask insertion.

Adult↗
PubMedDate not supplied

[Noninvasive mask ventilation of the lungs in the treatment of acute respiratory insufficiency in heart surgery patients in the postoperative period].

Noninvasive ventilation of the lungs using a mask (NIVLM) was used in 54 patients with hypercapnic (n = 14) and hypoxemic (n = 40) respiratory failure. Respironics (USA) nasal and facial masks were applied. Ventilation regimens were selected individually. Trigger monitored ventilation, intermittent forced ventilation of the lungs, and assisted ventilation with positive expiratory pressure, biphasic positive pressure in the airways, and constant positive pressure in the respiratory contour were used. The efficacy of NIVLM in patients with hypercapnic respiratory failure was 100%. The pCO2 and ETCO2 normalized in all patients both during and after discontinuation of NIVLM. Despite a relatively long period of ventilation (229 +/- 72 min), the patients did not complain of discomfort during the procedure; no complications or individual intolerance of nasal or facial masks were observed. In patients with hypoxemic respiratory failure NIVLM resulted in a decrease of dyspnea, increase of respiratory volume, etc. The detected changes did not disappear after NIVLM was discontinued. Individual tolerance of nasal and facial masks was somewhat worse in this group: patients complained of stuffiness, lack of air, difficult respiration. Six patients (18.2%) developed episodes of psychomotor excitation which required sedative and analgesic therapy. In general, the efficacy of NIVLM was 91%, but resolution of respiratory failure without repeated intubation of the trachea was attained in only 33 patients (87%) with the hypoxemic condition. The mean duration of NIVLM in this group was 464 +/- 47 min. Hence, NIVLM is an effective method for respiratory support in patients with both hypoxemic and hypercapnic respiratory failure, which helps decrease the duration of forced ventilation of the lungs or do without repeated intubation of the trachea.

Acute Disease↗
PubMed1998

[Meningitis is a rare complication of spinal anesthesia. Good hygiene and face masks are simple preventive measures].

Although bacterial meningitis is a rare sequela of spinal anaesthesia, occasional case reports continue to appear in anaesthesiological literature. The article presents nine cases of iatrogenic meningitis reported to the treatment injury claims authority. Eight of these patients had undergone spinal anaesthesia, and one myelography. Alpha-haemolytic streptococci were isolated in cerebrospinal fluid culture in seven cases, the remaining two cases being culture-negative. Although alpha-haemolytic streptococci are normal commensals of the upper respiratory tract and mouth and rarely cause spontaneous meningitis, they have been implicated in several reported cases of iatrogenic meningitis. The risk of such infection raises the issue of the widespread habit of omitting face masks when performing dural puncture. As these bacteria are not known to cause infection in general surgery, the necessity of using face masks in the operating theatre has been questioned. However, the use of face masks has been shown to reduce the risk of bacterial contamination from the upper airway; and as available documentation on iatrogenic meningitis suggests oral commensals to be responsible, the use of face masks should be mandatory whenever any kind of lumbar puncture is performed.

Aged↗
PubMed1998

Laryngeal mask airway: indications and management for critical care.

The laryngeal mask airway is the newest tool for airway management during the perianesthesia period. This device has joined other resuscitation equipment on emergency carts. Critical care nurses must be prepared to care for patients for whom laryngeal mask airways are indicated and used. A solid understanding of the purpose and placement of the laryngeal mask airway is necessary for safe removal of the device. Policies and procedures should be developed to define standards of care and responsibilities for care of patients with a laryngeal mask airway.

Adult↗
PubMed1997

Excimer laser correction of astigmatism using erodible masks.

PURPOSE: The latest development in the erodible mask technology is an excimer laser containing the mask in the laser optical pathway. This paper reports the results of the first human series of consecutive treatments performed for the correction of compound myopic astigmatism. METHODS: We have treated 83 eyes. Spherical equivalent attempted correction ranged between -1.75 and -11.75 D (mean -7.07 +/- 2.45 D), astigmatic attempted correction ranged between -1.00 and -5.00 D (mean -2.42 +/- 1.02 D). The sphere correction was made by diaphragm using a multi-zone software with three ablation zones: 100% of the total attempted correction for the central 5.0 mm zone, 70% for the second 6.0 mm zone, 30% for the outer 6.5 mm zone. Cylinder correction was made sequentially after myopic correction using the appropriate mask. RESULTS: One month after treatment, mean refractive error was +1.07 +/- 1.24 D (range +4.50/-1.75 D) for spherical equivalent, and -0.49 +/- 0.57 D (range +0.75/-2.00 D) for astigmatism. Forty-eight eyes (57.8%) had uncorrected visual acuity of 20/40 or better. At six months, mean refractive error was +0.42 +/- 0.97 D (range +3.75/-1.00 D) for spherical equivalent, and -0.44 +/- 0.51 D (range +0.25/-3.00 D) for astigmatism. Vector analysis showed that 57 eyes (68.7%) had 5 or less degrees rotation. Seventy-two (86.7%) and 54 eyes (65.1%) had uncorrected visual acuity equal or better than 20.40 and 20/25 respectively. One eye (1.2%) showed a best corrected visual acuity loss of more than one line, but 8 eyes (9.6%) had a gain of more than one line. One-year results on a smaller series (33 eyes) overlap the six-month results. CONCLUSIONS: The mask in-the-rail excimer laser delivery system appears to be effective and predictable in the correction of compound myopic astigmatism. We observed no significant regression of the astigmatic correction over time. Longer follow-up on larger series is necessary to draw final conclusions.

Adolescent↗
PubMed1998

[Intubating laryngeal mask].

To improve the success of blind intubation through a laryngeal mask, Dr. A.I.J. Brain constructed the intubating laryngeal mask airway (ILMA), marketed under the name Fastrach. The new construction allows blind intubation with highly flexible endotracheal tubes up to 8 mm ID with cuff (straight Woodbridge type), securing the airway around the intubation process and maintaining most of the characteristics of a standard laryngeal mask airway (SLMA), including contraindications. An additional contraindication is the existence of a Zenker diverticle. Up to now, eight working groups reported a success rate of blind intubation through the ILMA of more than 90% in about 1,200 patients, with a success rate of blind intubation of more than 50% for the first intubation attempt. Ten percent of the patients were difficult to intubate with the same success rate for blind intubation as in normal patients. Reduced mouth opening does not seem to hinder the use of the ILMA in spite of its increased outer diameter of 2 cm, as long as it is possible to enlarge the mouth opening to > 2 cm during anaesthesia. The new ILMA more than doubles the success of blind intubation compared to an SLMA, irrespective of a large variety of intubation difficulties. Correct judgement of endotracheal tube position is mandatory. The ILMA has the potential to be used in patients who are difficult to intubate and to substitute the SLMA in "cannot ventilate--cannot intubate" situations. The future will show if the ILMA also will improve emergency airway management by inexperienced personnel, including intubation, as has been shown for the standard laryngeal mask airway in cardiopulmonary resuscitation for ventilation only.

Contraindications↗
PubMed1998

[Ventilation using the laryngeal mask and intubation tube during general anesthesia for ophthalmic surgery].

PURPOSE: The aim of the investigation was to compare efficacy of using for airway maintainance and controlled ventilation the laryngeal mask versus orotracheal intubation. MATERIALS AND METHODS: We carried outs this examination in the group of 50 patient of both sex scheduled for elective operations in ophthalmic surgery. All participants were of I or II class of perioperative risk according to ASA scale. We tried to estimate efficacy of using laryngeal mask versus orotracheal intubation during anaesthesia with controlled ventilation. We examined capillary blood hemoglobin saturation, carbon dioxide pressure in end-tidal expired gas and peak inspiratory pressure while laryngeal mask or orotracheal tube was applied. RESULTS: We found no differences of clinical importance in both group of patients in the range of measured parameters. CONCLUSION: We conclude that ventilation with the laryngeal mask inserted is safe and effective providing that patients are carefully selected.

Adult↗
PubMed1998

FISH identifies inv(16)(p13q22) masked by translocations in three cases of acute myeloid leukemia.

The inv(16)(p13q22) masked by different translocations was detected by fluorescence in situ hybridization (FISH) and confirmed by molecular analysis in three adult patients presenting with acute myeloid leukemia (AML)-M2 (cases 1 and 3) and M4Eo (case 2). Cytogenetic analysis revealed 47,XX,t(9;16)(p23;p13),+22 (case 1); 46,XX,t(1;16)(p32;p13) (case 2); and 46,XY,?del(16)(q22) (case 3). Using a panel of probes for chromosomes 1, 9, 16, and 20 as well as probes to detect inv(16), i.e., two cosmid contigs hybridizing proximally and distally to the 16p13 breakpoint, FISH demonstrated inv(16) involving the derivative 16 as well as reciprocal translocations between 16q22-qter and 9p24 (case 1), 1p32 (case 2), and 20q13 (case 3). In addition, a small interstitial del(16)(p13p13) proximal to the MYH11 breakpoint was detected in case 1. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot analysis showed a CBFB-MYH11 fusion transcript and MYH11 rearrangement, respectively, in all three cases. We conclude that: 1) inv(16) can be masked by other structural abnormalities involving chromosome 16; 2) some of the so-called variant translocations not explored at the molecular level may in fact represent a masked inv(16); and 3) FISH, RT-PCR, and Southern blot analyses are reliable tools to detect masked inv(16) and should be applied in all AML cases with structural changes of chromosome 16.

Adult↗
PubMed1990

Chemical residues of ganglioside molecules involved in interactions with lymphocyte surface targets leading to CD4 masking and inhibition of mitogenic proliferation.

Human lymphocyte CD4 becomes undetectable in the presence of exogenous gangliosides (CD4 masking), as originally described by Offner et al. (J. Immunol. 1987. 139: 3295). CD4 masking is apparently due to in situ rearrangement of the glycoprotein; since no direct binding of ganglioside to CD4 could be demonstrated, it was suggested that the effect could be mediated by interactions with other, as yet unidentified, surface structures. To gain insight into the structural requirements of the interaction(s) that leads to CD4 masking, we assayed the effects of a battery of gangliosides and of ganglioside derivatives on (a) CD4 masking; (b) cholera toxin binding (as a well known ganglioside-protein interaction) and (c) inhibition of lymphocyte mitogenic proliferation (as a second ganglioside interaction with a lymphocyte surface target). Our results indicate that the three interactions are distinctly different, since ganglioside chemical groups which are essential for one of the interactions are irrelevant for the others, and lead to the conclusion that gangliosides can interact with lymphocyte surface targets in a number of ways, causing a number of independent biological effects.

CD4 Antigens↗
PubMed1996

Unmasking mRNA in clam oocytes: role of phosphorylation of a 3' UTR masking element-binding protein at fertilization.

During meiotic maturation or after fertilization of invertebrate and vertebrate oocytes, many of the quiescent stored mRNAs are recruited into polysomes. In the clam, Spisula solidissima, such masked messages include the abundant mRNAs encoding cyclin A and the small subunit of ribonucleotide reductase. We have previously shown that mRNA-specific unmasking of these two messages can be achieved in vitro, in oocyte cell-free extracts, by the addition of antisense RNAs corresponding to a fairly short (130-140 nucleotides) segment in their cognate 3' untranslated regions. We postulated that the antisense RNAs prevented the binding of a masking repressor protein (Standart et al., 1990). Here we report UV-crosslinking and gel retardation studies which show that the masking portions of the translationally regulated mRNAs bind an oocyte protein of 82 kDa (p82), which is phosphorylated after fertilization. This modification was accompanied by altered RNP complex formation in gel retardation assays. These changes presumably reflect the activation of translation of the masked mRNAs. The role of p82 phosphorylation in maternal mRNA unmasking was assessed in a novel in vitro activation system developed from clam oocytes, based upon the natural rise in pH which accompanies fertilization. Concomitant with mRNA unmasking, several kinases, including cdc2 and MAP kinases were activated in this system, as was p82 phosphorylation. Inhibitors of serine/threonine kinases, including 6-DMAP, staurosporine, and H7 inhibited p82 phosphorylation, whereas inhibitors of tyrosine kinases, protein kinase C, cAMP-dependent protein kinase, and p70s6k did not prevent this modification. A specific inhibitor of cdc2 kinase, p27Kip1, prevented p82 phosphorylation and translational activation, strongly suggesting that p82 modification is required for unmasking.

Amino Acid Sequence↗
PubMed2001

Spatial normalization of brain images with focal lesions using cost function masking.

In studies of patients with focal brain lesions, it is often useful to coregister an image of the patient's brain to that of another subject or a standard template. We refer to this process as spatial normalization. Spatial normalization can improve the presentation and analysis of lesion location in neuropsychological studies; it can also allow other data, for example from functional imaging, to be compared to data from other patients or normal controls. In functional imaging, the standard procedure for spatial normalization is to use an automated algorithm, which minimizes a measure of difference between image and template, based on image intensity values. These algorithms usually optimize both linear (translations, rotations, zooms, and shears) and nonlinear transforms. In the presence of a focal lesion, automated algorithms attempt to reduce image mismatch between template and image at the site of the lesion. This can lead to significant inappropriate image distortion, especially when nonlinear transforms are used. One solution is to use cost-function masking-masking the areas used in the calculation of image difference-to exclude the area of the lesion, so that the lesion does not bias the transformations. We introduce and evaluate this technique using normalizations of a selection of brains with focal lesions and normal brains with simulated lesions. Our results suggest that cost-function masking is superior to the standard approach to this problem, which is affine-only normalization; we propose that cost-function masking should be used routinely for normalizations of brains with focal lesions.

Adult↗
PubMed1988

Transposition of c-abl oncogene in a case of masked Ph chromosome duplicated in blastic phase.

A female with chronic myelocytic leukemia (CML) in blastic phase (BP) showed a masked Ph chromosome that had originated by a translocation between chromosomes 8 and 22, with no obvious involvement of chromosome 9. A duplication of the masked Ph and trisomy 13 were present as additional anomalies. The karyotype on peripheral blood unstimulated cultures was 48,XX,t(8;22)(p12;q11),+13,+der(22) t(8;22)/47,XX,t(8;22)(p12;q11),+der(22)t(8;22). While the duplication of the Ph is a frequent finding in BP of CML, we did not find any other case in the literature with duplication of a masked Ph. In situ hybridization with c-abl and bcr probes showed that a 3' bcr sequence was translocated to the der(8) chromosome, while the c-abl oncogene was transposed to the masked Ph.

Blast Crisis↗