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1.
Phys Rev Lett ; 123(10): 100507, 2019 Sep 06.
Article in English | MEDLINE | ID: mdl-31573313

ABSTRACT

We consider the characterization of entanglement depth in a quantum many-body system from the device-independent perspective; that is, we aim at certifying how many particles are genuinely entangled without relying on assumptions on the system itself nor on the measurements performed. We obtain device-independent witnesses of entanglement depth (DIWEDs) using the Bell inequalities introduced in [J. Tura et al., Science 344, 1256 (2014)SCIEAS0036-807510.1126/science.1247715] and compute their k-producibility bounds. To this end, we exploit two complementary methods: first, a variational one, yielding a possibly optimal k-producible state; second, a certificate of optimality via a semidefinite program, based on a relaxation of the quantum marginal problem. Numerical results suggest a clear pattern on k-producible bounds for large system sizes, which we then tackle analytically in the thermodynamic limit. Contrary to existing DIWEDs, the ones we present here can be effectively measured by accessing only collective measurements and second moments thereof. These technical requirements are met in current experiments, which have already been performed in the context of detecting Bell correlations in quantum many-body systems of 5×10^{2}-5×10^{5} atoms.

2.
Neurología (Barc., Ed. impr.) ; 32(1): 22-28, ene.-feb. 2017. tab, graf
Article in Spanish | IBECS | ID: ibc-160469

ABSTRACT

Introducción: En la fase aguda del ictus el 30% de los pacientes presentan disfagia, y de ellos, el 50% experimentarán broncoaspiración. Nuestro objetivo fue evaluar los resultados de mortalidad y broncoaspiración del test del agua comparado con el test 2 volúmenes/3 texturas controlado con pulsioximetría (2v/3t-P) en una unidad de ictus. Pacientes y métodos: Durante 5 años se analizaron de forma prospectiva y consecutiva todos los pacientes con infarto cerebral en la Unidad de Ictus. Del año 2008 al 2010 se utilizó el test del agua (grupo 0 o G0), y del 2011 al 2012, el test 2v/3t-P (grupo 1 o G1). Se recogieron las siguientes variables: demográficas, factores de riesgo vascular, gravedad neurológica con la escala NIHSS, subtipo etiológico según criterios TOAST, subtipo clínico según la clasificación Oxfordshire, prevalencia de disfagia, broncoaspiración y exitus. Resultados: Se analizaron 418 pacientes con infarto cerebral agudo (G0 = 275, G1 = 143). Se detectaron diferencias significativas entre ambos grupos en el porcentaje de pacientes con TACI (17% en G0 vs. 29% en G1, p = 0,005) y en la mediana de NIHSS (4 puntos en G0 vs. 7 puntos en G1, p = 0,003). Con el test 2v/3t-P se detectó un aumento no significativo en el porcentaje de disfagia (22% en G0 vs. 25% en G1, p = 0,4), una menor tasa de mortalidad (1,7% en G0 vs. 0,7% en G1, p = 0,3) y una reducción significativa de broncoaspiración (6,2% en G0 vs. 2,1% en G1, p = 0,05). Conclusiones: El nuevo test 2v/3t-P, comparado con el test del agua, mejoró significativamente los resultados de broncoaspiración en los pacientes con infarto cerebral agudo


Introduction: During acute stroke, 30% of all patients present dysphagia and 50% of that subgroup will experience bronchoaspiration. Our aim was to compare mortality and bronchoaspiration rates associated with the water test compared to those associated with a 2 volume/3 texture test controlled with pulse oximetry (2v/3t-P test) in our stroke unit. Patients and methods. Over a 5-year period, we performed a prospective analysis of all consecutive acute ischaemic stroke patients hospitalised in the Stroke Unit. Dysphagia was evaluated using the water test between 2008 and 2010 (group 0 or G0), and the 2v/3t-P test (group 1 or G1) between 2011 and 2012. We analysed demographic data, vascular risk factors, neurological deficit on the NIHSS, aetiological subtype according to TOAST criteria, clinical subtype according to the Oxfordshire classification, prevalence of dysphagia, percentage of patients with bronchoaspiration, and mortality. Results: We examined 418 patients with acute stroke (G0 = 275, G1 = 143). There were significant differences between the 2 groups regarding the percentage of patients with TACI (17% in G0 vs. 29% in G1, P = .005) and median NIHSS score (4 points in G0 vs. 7 points in G1, P = .003). Since adopting the new swallowing test, we detected a non-significant increase in the percentage of dysphagia (22% in G0 vs. 25% in G1, P = .4), lower mortality (1.7% in G0 vs. 0.7% in G1, P = .3) and a significant decrease in the bronchoaspiration rate (6.2% in G0 vs. 2.1% in G1, P = .05). Conclusions: Compared to the water test used for dysphagia screening, the new 2v/3t-P test lowered bronchoaspiration rates in acute stroke patients


Subject(s)
Humans , Male , Female , Cerebral Infarction/diagnosis , Cerebral Infarction/etiology , Deglutition Disorders/complications , Deglutition Disorders/diagnosis , Biopsy, Needle/statistics & numerical data , Risk Factors , Stroke/complications , Stroke/diagnosis , Prospective Studies , Deglutition , Indicators of Morbidity and Mortality , Multivariate Analysis
3.
Neurologia ; 32(1): 22-28, 2017.
Article in English, Spanish | MEDLINE | ID: mdl-25660184

ABSTRACT

INTRODUCTION: During acute stroke, 30% of all patients present dysphagia and 50% of that subgroup will experience bronchoaspiration. Our aim was to compare mortality and bronchoaspiration rates associated with the water test compared to those associated with a 2 volume/3 texture test controlled with pulse oximetry (2v/3t-P test) in our stroke unit. PATIENTS AND METHODS: Over a 5-year period, we performed a prospective analysis of all consecutive acute ischaemic stroke patients hospitalised in the Stroke Unit. Dysphagia was evaluated using the water test between 2008 and 2010 (group 0 or G0), and the 2v/3t-P test (group 1 or G1) between 2011 and 2012. We analysed demographic data, vascular risk factors, neurological deficit on the NIHSS, aetiological subtype according to TOAST criteria, clinical subtype according to the Oxfordshire classification, prevalence of dysphagia, percentage of patients with bronchoaspiration, and mortality. RESULTS: We examined 418 patients with acute stroke (G0=275, G1=143). There were significant differences between the 2 groups regarding the percentage of patients with TACI (17% in G0 vs. 29% in G1, P=.005) and median NIHSS score (4 points in G0 vs. 7 points in G1, P=.003). Since adopting the new swallowing test, we detected a non-significant increase in the percentage of dysphagia (22% in G0 vs. 25% in G1, P=.4), lower mortality (1.7% in G0 vs. 0.7% in G1, P=.3) and a significant decrease in the bronchoaspiration rate (6.2% in G0 vs. 2.1% in G1, P=.05). CONCLUSIONS: Compared to the water test used for dysphagia screening, the new 2v/3t-P test lowered bronchoaspiration rates in acute stroke patients.


Subject(s)
Deglutition Disorders/diagnosis , Mass Screening , Stroke/complications , Aged , Deglutition Disorders/etiology , Female , Hospitalization , Humans , Male , Prevalence , Prospective Studies , Risk Factors
5.
Br J Anaesth ; 96(5): 650-9, 2006 May.
Article in English | MEDLINE | ID: mdl-16574723

ABSTRACT

BACKGROUND: Superimposed high-frequency jet ventilation (SHFJV), which does not require any tracheal tubes or catheters, was developed specifically for use in laryngotracheal surgery. SHFJV uses two jet streams with different frequencies simultaneously and is applied in the supraglottic space using a jet laryngoscope and jet ventilator. METHODS: Between 1990 and 2004, SHFJV was studied in 1515 consecutive patients (including 158 children requiring laryngotracheal surgery) prospectively. Ventilation was performed with an air/oxygen mixture and anaesthesia was administered i.v. RESULTS: Adequate oxygenation and ventilation was achieved in 1512 patients. Arterial blood gas analyses (BGA) were performed between 1990 and 1994; thereafter BGA was only performed in patients with high-grade stenosis of the larynx/trachea or high-risk patients [n=623, mean Pa(O(2)) 133.8 (39.4) mm Hg and mean Pa(CO(2)) 42.3 (10.1) mm Hg]. There were no significant changes in Pa(O(2)) or Pa(CO(2)) during the entire period of SHFJV. No complications secondary to the ventilation technique were observed; in particular, no barotrauma occurred. Three patients required tracheal intubation. SHFJV was also successfully used for laser surgery (n=312). It proved to be a safe mode of ventilation without any complications such as airway fire, major haemorrhage, or aspiration of debris. CONCLUSION: SHFJV is an advanced ventilation mode playing a pivotal role in the (open) ventilatory support/ventilation of patients with laryngotracheal stenosis. It is particularly indicated in cases of severe stenosis and offers optimal conditions for laryngotracheal surgery, including laser surgery and stent implantation techniques.


Subject(s)
High-Frequency Jet Ventilation/methods , Laryngostenosis/surgery , Tracheal Stenosis/surgery , Adult , Aged , Carbon Dioxide/blood , Female , Humans , Laryngoscopes , Laryngoscopy , Laser Therapy , Male , Middle Aged , Oxygen/blood , Partial Pressure , Prospective Studies
6.
Anesth Analg ; 91(6): 1506-12, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11094009

ABSTRACT

UNLABELLED: We tested the respiratory efficacy of different jet ventilation techniques (subglottic low-frequency versus subglottic combined-frequency and subglottic combined-frequency versus supraglottic combined frequency) in patients undergoing microlaryngeal surgery. The PaCO(2) and the quotient of arterial oxygen tension (PaO(2)) over FIO(2) were measured. After anesthetic induction (propofol, remifentanil, vecuronium), an endotracheal Mon-Jet catheter (Xomed, Jacksonville, FL) for subglottic jet ventilation and a laryngoscope for supraglottic jet ventilation (Carl Reiner G.m.b.H., Vienna, Austria) were inserted. In Group 1 (n = 18), subglottic low-frequency (15 breaths/min), combined-frequency (600 and 15 breaths/min), and low-frequency jet ventilation was subsequently performed (15 min each). In Group 2 (n = 19), the sequence was supraglottic, subglottic, and supraglottic combined-frequency jet ventilation. The driving pressures were initially adjusted to achieve normocapnia and were not changed during the entire study period. The FIO(2) was measured endotracheally. The Wilcoxon's signed rank test was applied. In Group 1, PaCO(2) and PaO(2)/FIO(2) improved significantly after switching from subglottic low-frequency to subglottic combined-frequency jet ventilation (PaCO(2), from 46.6 +/-8.3 to 42.1+/-8.1 mm Hg; PaO(2)/FIO(2), from 311+/-144 to 361+/-141 mm Hg; P<0.05). In Group 2, PaCO(2) increased and PaO(2)/FIO(2) decreased significantly after switching from supraglottic to subglottic combined-frequency jet ventilation (PaCO(2), from 39.4+/-7.1 to 45.9+/-7.5 mm Hg; PaO(2)/FIO(2), from 415+/-114 to 351+/-129 mm Hg; P<0.05). We conclude that subglottic combined-frequency jet ventilation is less effective than supraglottic combined-frequency ventilation, but more effective than subglottic low-frequency jet ventilation. IMPLICATIONS: The combination of high and low respiratory frequencies (600 and 15 breaths/min) improves pulmonary gas exchange during subglottic jet ventilation via an endotracheal catheter. However, subglottic combined-frequency jet ventilation is less effective than supraglottic combined-frequency jet ventilation via a jet ventilation laryngoscope.


Subject(s)
Glottis/physiology , High-Frequency Jet Ventilation , Larynx/surgery , Respiration, Artificial , Adult , Airway Resistance/physiology , Blood Gas Analysis , Carbon Dioxide/blood , Female , Humans , Hypercapnia/blood , Hypercapnia/etiology , Laryngoscopy , Lung Compliance/physiology , Male , Microsurgery , Middle Aged
7.
Article in German | MEDLINE | ID: mdl-10992962

ABSTRACT

OBJECTIVE: Single-frequency high-frequency jet ventilation (HFJV) is an established ventilatory technique during laryngotracheal surgery. This study describes the clinical use of combined HFJV, characterised by the simultaneous application of a low-frequent (LF) and a high-frequent (HF) jet stream. METHODS: Two jet streams with different pulsatile frequency (HF approx. 10 Hz, LF 10-30 bpm) and adjustable driving pressures were applied supraglottically by means of a special jet laryngoscope in patients undergoing elective laryngotracheal surgery during total intravenous anaesthesia. HFJV was performed using a pneumatic or electronic jet respirator connected to the central gas supply. RESULTS: 134 patients were submitted to tubeless HFJV applying the double-jet technique using the jet-laryngoscope. Duration of HFJV was < or = 30 min in 60 patients (45%), between 30 and 60 min in 49 patients (36%), and > or = 60 min in 25 patients (19%). Classification into 3 groups according to weight ((I < 65 kg, II = 65-84 kg, III > or = 85 kg) using driving pressures of 1.52 +/- 0.47 bar, 1.64 +/- 0.78 bar, and 1.69 +/- 0.67 bar for the HF jet and 1.78 +/- 0.54 bar, 1.90 +/- 0.48 bar, and 2.00 +/- 0.49 bar for the NF jet demonstrated differences in paO2 (156 +/- 45 [I] vs 126 +/- 34 [II] vs 96 +/- 18 [III] mm Hg) and paCO2 (42 +/- 9 und 44 +/- 8 vs 48 +/- 8 mm Hg) using comparable FjetO2 (0.6 +/- 0.2). Supraglottic pressures were 11.6 +/- 6.8, 11.5 +/- 7.0, und 12.6 +/- 7.1 cm H2O (I-III). No ventilator-related adverse events were observed. CONCLUSION: Tubeless supraglottic HFJV utilizing two jet streams with low and high frequency was effective in patients during laryngotracheal surgery. The application of two jet streams results in phasic changes of airway pressures between an inspiratory and expiratory pressure level, and facilitates application of enlarged tidal volumes. As demonstrated, oxigenation and ventilation is compromised by increased body weight. Superimposed HFJV (double-jet technique) enables the supraglottic ventilation of heavy patients and/or in the presence of airway stenoses during laryngotracheal surgery without need to use maximum driving pressures.


Subject(s)
High-Frequency Jet Ventilation , Larynx/surgery , Trachea/surgery , Adult , Aged , Aged, 80 and over , Female , Humans , Intraoperative Period , Laryngoscopy , Male , Middle Aged
9.
Eur J Anaesthesiol ; 17(7): 418-30, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10964143

ABSTRACT

Respiratory support with high-frequency jet ventilation has been advocated during airway surgery or to improve pulmonary mechanics and gas exchange in patients with bronchopleural fistulae or pulmonary insufficiency. Despite a large body of published evidence describing its benefits as an alternative ventilatory approach in anaesthesia and intensive care medicine, its application has not gained widespread acceptance and is restricted to specialized centres. To review the literature on high-frequency jet ventilation in European and North American institutions, we performed a search in a computerized database (MEDLINE) covering the period from 1990 until the present time, describing the use of high-frequency jet ventilation in over 7000 patients. Various modes to apply high-frequency jet ventilation during airway surgery have been established, but its value in intensive care is controversial. We report our experience with combined high-frequency jet ventilation and provide guidelines for its safe application.


Subject(s)
High-Frequency Jet Ventilation , Anesthesia, General , Bronchial Fistula/therapy , Critical Care , Europe , High-Frequency Jet Ventilation/adverse effects , High-Frequency Jet Ventilation/instrumentation , High-Frequency Jet Ventilation/methods , High-Frequency Jet Ventilation/statistics & numerical data , Humans , Monitoring, Physiologic , North America , Pleural Diseases/therapy , Practice Guidelines as Topic , Pulmonary Gas Exchange/physiology , Respiratory Insufficiency/therapy , Respiratory Mechanics/physiology , Respiratory System/surgery , Respiratory Tract Fistula/therapy , Treatment Outcome , Ventilators, Mechanical
10.
Acta Anaesthesiol Scand ; 44(4): 475-9, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10757585

ABSTRACT

BACKGROUND: High-frequency jet ventilation (HFJV) is an alternative ventilatory approach in airway surgery and for facilitating gas exchange in patients with pulmonary insufficiency. We have developed a new technique of combined HFJV utilising two superimposed jet streams. In this study we describe the application of tubeless supralaryngeal HFJV during laryngotracheal laser surgery in infants and children. METHODS: Tubeless combined HFJV characterised by the simultaneous supralaryngeal application of a low-frequency (LF) and a high-frequency (HF) jet stream was evaluated in a clinical study in 10 children undergoing elective laryngotracheal CO2 laser surgery. Additionally, pressure and flow characteristics were determined with the use of a paediatric test lung. HFJV was applied by means of a modified Kleinsasser laryngoscope with integrated metal injectors. In addition to pulse oximetry, monitoring of ECG, heart rate and blood pressure, supraglottic airway pressure was measured and arterial blood gases were analysed. RESULTS: Tubeless combined HFJV was used in 10 infants and children (mean age 4.6 yr, range 2 months-10 years) undergoing 17 consecutive endoscopic procedures with CO2 laser microsurgery of the larynx or the trachea under general anaesthesia. The mean duration of supralaryngeal HFJV was 46 min (range 15-75 min). Mean driving pressures of the HF and the LF jet streams were 0.75 bar and 0.95 bar, respectively. Inspiratory oxygen ratios were in the range 0.4-1.0. HFJV resulted in mean PaO2 and PaCO2 values of 19.7 kPa and 6.1 kPa, respectively. No complications during HFJV were observed. In the test lung, combined HFJV applied with driving pressures of 0.7-1.0 bar and 0.9-1.2 bar for HF and LF jet ventilation, respectively, resulted in maximum peak and baseline distal airway pressures of 17.6 cm H2O and 5.4 cm H2O, respectively. CONCLUSION: The application of the combined double frequency HFJV was effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses. It provided good visibility of anatomical structures and offered space for surgical manipulation, avoiding the use of combustible material inside the larynx or trachea.


Subject(s)
Anesthesia, Intravenous , High-Frequency Jet Ventilation/methods , Larynx/surgery , Laser Therapy , Trachea/surgery , Child , Child, Preschool , High-Frequency Jet Ventilation/instrumentation , Humans , Infant , Laryngoscopy
11.
Anesth Analg ; 90(2): 460-5, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10648340

ABSTRACT

UNLABELLED: We compared the efficacy of gas exchange during supraglottic combined-frequency jet ventilation via a jet ventilation laryngoscope and during monofrequent jet ventilation via the Mon-Jet catheter (Xomed, Jacksonville, FL). Twenty-three anesthetized (propofol, fentanyl, vecuronium) patients undergoing microlaryngeal surgery were prospectively studied and randomly assigned to one of two groups. The patients' lungs were ventilated with combined-frequency jet ventilation (10 min, 15 and 600 breaths/min, inspiration/expiration time ratio = 1, driving pressure 750-1500 mm Hg), monofrequent (low-frequency group: 15 breaths/min; high-frequency group: 600 breaths/min) jet ventilation (20 min), and again combined-frequency jet ventilation (15 min). PaO(2), PaCO(2), and the inspiratory oxygen fraction (FIO(2)) were measured. Wilcoxon's signed rank test was applied. During monofrequent jet ventilation, PaCO(2) increased and the PaO(2)/FIO(2) decreased significantly (P < 0.05) as compared with combined-frequency jet ventilation (low-frequency group: PaCO(2) from 39.4 +/- 3.3 to 50. 8 +/- 8.0 mm Hg, PaO(2)/FIO(2) from 306 +/- 100 to 225 +/- 94 mm Hg; high-frequency group: PaCO(2) from 36.7 +/- 7.2 to 60.3 +/- 6.1 mm Hg, PaO(2)/FIO(2) from 429 +/- 87 to 190 +/- 51 mm Hg; mean +/- SD). After switching back to combined-frequency jet ventilation, PaCO(2) decreased and PaO(2)/FIO(2) increased to baseline levels. We conclude that gas exchange during microlaryngeal surgery can be more easily maintained with supraglottic combined-frequency jet ventilation than with subglottic monofrequent jet ventilation via the Mon-Jet catheter. IMPLICATIONS: This study demonstrates that the combination of high- and low-frequency supraglottic jet ventilation via a jet ventilation laryngoscope provides a better pulmonary gas exchange and allows more accurate airway pressure monitoring during microlaryngeal surgery than subglottic monofrequent jet ventilation via an endotracheal catheter.


Subject(s)
Glottis/anatomy & histology , Larynx/surgery , Microsurgery , Respiration, Artificial , Adult , Air Pressure , Anesthesia, Inhalation , Blood Gas Analysis , Computer Simulation , High-Frequency Jet Ventilation , Humans , Lung/physiology , Manometry , Models, Anatomic , Prospective Studies
12.
Arch Otolaryngol Head Neck Surg ; 126(1): 40-4, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10628709

ABSTRACT

OBJECTIVE: To describe our experience with superimposed high-frequency jet ventilation (SHFJV), which does not require any endotracheal tubes or catheters, for performing laryngeal and tracheal surgery. DESIGN: A case series of 500 patients. SETTING: A university medical center. PATIENTS: Four hundred sixty adult patients and 40 children in a consecutive sample who required laryngeal or tracheal surgery under SHFJV. INTERVENTIONS: The SHFJV uses 2 jet streams with different frequencies simultaneously and is applied using a jet laryngoscope. Ventilation was performed with an air-oxygen mixture, and intravenous agents were used for anesthesia. Arterial blood gas values were analyzed. MAIN OUTCOME MEASURES: Reported values of oxygenation and ventilation during the application of SHFJV and laryngotracheal surgery. RESULTS: In 497 patients, adequate oxygenation with a mean +/- SD PaO2 of 91.8 +/- 22.9 mm Hg and ventilation with a PaCO2 of 29.7 +/- 5.5 mm Hg were achieved using SHFJV. The average duration of the application of ventilation was 27 minutes, and the longest duration was 118 minutes. No complications due to the ventilation technique were observed. Laser surgery was performed in 150 patients. CONCLUSIONS: The use of SHFJV in combination with the jet laryngoscope provides patients with sufficient ventilation during laryngotracheal surgery. Even in patients at high risk because of pulmonary or cardiac disease, this technique can be applied safely. In patients with stenosis, the ventilation is applied from above the stenosis, reducing the risk of barotrauma. The SHFJV can be used for tracheobronchial stent insertion, and laser can be used without any additional protective measures.


Subject(s)
High-Frequency Jet Ventilation , Laryngeal Diseases/surgery , Larynx/surgery , Trachea/surgery , Tracheal Diseases/surgery , Adolescent , Adult , Child , Child, Preschool , Female , High-Frequency Jet Ventilation/methods , Humans , Infant , Infant, Newborn , Laser Therapy , Male , Middle Aged , Tracheal Stenosis/surgery
15.
J Clin Anesth ; 11(1): 32-8, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10396716

ABSTRACT

STUDY OBJECTIVE: To evaluate right ventricular dimensions and function by echocardiography in anesthetized patients during superimposed high-frequency jet ventilation (HFJV). DESIGN: Prospective clinical study. SETTING: University hospital operating room. PATIENTS: 20 ASA physical status I patients undergoing elective minor otorhinolaryngological surgery, and undergoing conventional mechanical ventilation with subsequent superimposed HFJV. INTERVENTIONS: Two-dimensional transesophageal echocardiography with a 5-MHz multiplane transducer to determine right ventricular dimensions and function from a mid-esophageal view. Insertion of a radial artery catheter for monitoring blood pressure and blood gases. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean arterial blood pressure, and right ventricular end-diastolic and end-systolic volumes determined by echocardiography, stroke volume, and ejection fraction. Measurements were performed after 10 minutes of conventional positive pressure ventilation (control) and after 10 minutes of subsequent superimposed HFJV at similar peak and positive end-expiratory airway pressures. Right ventricular systolic and diastolic volumes, stroke volume, and ejection fraction did not reveal statistical significant differences after transition to HFJV. Interventricular septum did not show any abnormalities in motion. In contrast, interatrial septum demonstrated momentary mid-systolic bows toward the left atrium in 9 of 17 patients (53%) during conventional ventilation, but in 15 of 17 patients (88%) during jet ventilation. Heart rate and mean arterial blood pressure remained unchanged, but arterial oxygen tension values were higher and arterial carbon dioxide tension values lower during HFJV. CONCLUSION: Transesophageal echocardiographic evaluation of right heart hemodynamics did not show any significant difference after transition of ventilation to superimposed HFJV applying similar airway pressures. Furthermore, superimposed HFJV was safe and effective, it improved oxygenation, and it facilitated carbon dioxide elimination.


Subject(s)
Echocardiography/methods , Hemodynamics/physiology , High-Frequency Jet Ventilation , Ventricular Function, Right/physiology , Adult , Esophagus , Evaluation Studies as Topic , Female , Humans , Male
16.
Crit Care ; 3(4): 101-110, 1999.
Article in English | MEDLINE | ID: mdl-11056732

ABSTRACT

BACKGROUND: Adequate humidification in long-term jet ventilation is a critical aspect in terms of clinical safety. AIM: To assess a prototype of an electronic jet-ventilator and its humidification system. METHODS: Forty patients with respiratory insufficiency were randomly allocated to one of four groups. The criterion for inclusion in this study was respiratory insufficiency exhibiting a Murray score above 2. The four groups of patients were ventilated with three different respirators and four different humidification systems. Patients in groups A and B received superimposed high-frequency jet ventilation (SHFJV) by an electronic jet-ventilator either with (group A) or without (group B) an additional humidification system. Patients in group C received high-frequency percussive ventilation (HFPV) by a pneumatic high-frequency respirator, using a hot water humidifier for warming and moistening the inspiration gas. Patients in group D received conventional mechanical ventilation using a standard intensive care unit respirator with a standard humidification system. SHFJV and HFPV were used for a period of 100 h (4days). RESULTS: A significantly low inspiration gas temperature was noted in patients in group B, initially (27.2 +/- 2.5 degrees C) and after 2 days (28.0 +/- 1.6 degrees C) (P < 0.05). The percentage of relative humidity of the inspiration gas in patients in group B was also initially significantly low (69.8 +/- 4.1%; P < 0.05) but rose to an average of 98 +/- 2.8% after 2 h. The average percentage across all four groups amounted to 98 +/- 0.4% after 2 h. Inflammation of the tracheal mucosa was found in patients in group B and the mucosal injury score (MIS) was significantly higher than in all the other groups. Patients in groups A, C and D showed no severe evidence of airway damage, exhibiting adequate values of relative humidity and temperature of the inspired gas. CONCLUSION: The problems of humidification associated with jet ventilation can be fully prevented by using this new jet-ventilator. These data were sustained by nondeteriorating MIS values at the end of the 4-day study period in groups A, C and D.

17.
Br J Anaesth ; 83(6): 940-2, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10700796

ABSTRACT

We have developed a new technique of combined high-frequency jet ventilation (HFJV), characterized by simultaneous application of a low-frequency (LF) and a high-frequency (HF) jet stream. Tubeless supralaryngeal jet ventilation was delivered via a modified Kleinsasser laryngoscope. We studied 44 adults undergoing 45 elective surgical procedures of the larynx and trachea using a carbon dioxide laser during HFJV. Applied inspiratory oxygen ratios ranged from 0.4 to 1.0. Mean driving pressures of the HF and LF jet streams were 1.5 bar and 1.8 bar in adults, respectively. Mean duration of HFJV was 41 (range 10-180) min. HFJV resulted in mean PaO2 and PaCO2 values of 16.6 (range 9.8-26.9) kPa and 5.7 (3.0-7.6) kPa, respectively. Tubeless supralaryngeal HFJV was safe and effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses, providing optimal visibility of anatomical structures, offering maximum space for surgical manipulation, and avoiding the use of combustible material inside the larynx or trachea.


Subject(s)
High-Frequency Jet Ventilation/methods , Larynx/surgery , Laser Therapy/instrumentation , Trachea/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Humans , Laryngoscopes , Middle Aged
20.
Anaesthesist ; 47(3): 209-19, 1998 Mar.
Article in German | MEDLINE | ID: mdl-9567154

ABSTRACT

UNLABELLED: Despite advances and technical developments in the area of intensive care medicine it has not been possible to lower the mortality of patients with pulmonary insufficiency. Therefore, alternative ventilation strategies have been developed and applied. One of these ventilation techniques is superimposed high-frequency jet ventilation (SHFJV). For optimal application of SHFJV we designed a special jet-adapter. METHODS: This jet-adapter made of plastic consists of a T-piece and four central, small-bore cannulas and can be connected to any commercially available endotracheal tube. Therefore, it does not require reintubation with an endotracheal jet tube when beginning SHFJV. The simultaneous high-frequency and low-frequency jet ventilation is performed over two jet-nozzles that have been designed according to optimal flow dynamic measurements. Two further cannulas are used for continuous airway pressure monitoring and humidification of the applied gases. A pre-warmed and humidified bias flow with exactly defined oxygen concentration is led through the cross-part of the T-piece for gas entrainment. Additionally, the cross-part contains a port that can be opened for endotracheal suctioning or bronchoscopy and makes disconnection of the jet adapter from the endotracheal tube for either purpose unnecessary. CONCLUSION: The jet adapter can be used: (1) to apply SHFJV; (2) to measure airway pressures continuously; (3) to humidify and warm inspired gases; (4) to administer medications or add nitrous oxide by the inspiratory route, enabling combination with new therapeutic possibilities in the management of patients with severe ARDS.


Subject(s)
Critical Care , High-Frequency Jet Ventilation/instrumentation , Anesthesia, Inhalation , Bronchoscopy , Evaluation Studies as Topic , High-Frequency Jet Ventilation/methods , Humans , Humidity , Intubation, Intratracheal , Respiratory Distress Syndrome/therapy
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