Airway Leak Research Articles

Application of placing the anterior end of endotracheal tube at the glottis in laryngeal mask airway positive ventilation during general anesthesia: A prospective, randomized, controlled trial.

Glottic contraction and closure causes ventilation obstruction and laryngeal mask airway (LMA) leakage during positive pressure ventilation using LMA. This study aimed to assess the effect of placing the anterior end of the endotracheal tube (ET) at the glottis through the LMA ventilation conduit on treating LMA leakage following glottic contraction and closure. In this prospective, randomized, controlled trial, patients with non-minor surgery using LMA ventilation were randomly allocated to the i-gel group (group L) and the i-gel combined with ET group (group LE). The tip of ET was placed 2 cm under glottis guided by fiberoptic bronchoscope through i-gel ventilation conduit in group LE. The perioperative incidence of i-gel leakage, the changes of systolic blood pressure (SBP) and heart rate (HR) following artificial airway insertion, and adverse events were recorded. Perioperative i-gel leakage was observed in 7 of 48 patients (14.6%) in group L and 1 of 49 patients (2.0%) in group LE. There was significant difference in the incidence of leakage between the 2 groups (P = .031). SBP and HR after ET insertion in group LE increased significantly compared to those in group L (P < .05/5). The values of both SBP and HR after ET insertion did not exceed the basic values in group LE (P > .05/4). There were no significant differences in the incidence and severity of postoperative sore pain and hoarseness, cough during i-gel and ET removal between the 2 groups (P > .05). Placing the anterior end of ET at the glottis reduced LMA air leakage related to glottic contraction and closure in non-minor surgery. The ET placing had low stress response and did not significantly increase postoperative complications.

A Precise Pulmonary Airway Tree Segmentation Method Using Quasi-Spherical Region Constraint and Tracheal Wall Gap Sealing.

Accurate segmentation of the pulmonary airway tree is crucial for diagnosing lung diseases. To tackle the issues of low segmentation accuracy and frequent leaks in existing methods, this paper proposes a precise segmentation method using quasi-spherical region-constrained wavefront propagation with tracheal wall gap sealing. Based on the characteristic that the surface formed by seed points approximates the airway cross-section, the width of the unsegmented airway is calculated, determining the initial quasi-spherical constraint region. Using the wavefront propagation method, seed points are continuously propagated and segmented along the tracheal wall within the quasi-spherical constraint region, thus overcoming the need to determine complex segmentation directions. To seal tracheal wall gaps, a morphological closing operation is utilized to extract the characteristics of small holes and locate low-brightness tracheal wall gaps. By filling the CT values at these gaps, the method seals the tracheal wall gaps. Extensive experiments on the EXACT09 dataset demonstrate that our algorithm ranks third in segmentation completeness. Moreover, its performance in preventing airway leaks is significantly better than the top-two algorithms, effectively preventing large-scale leak-induced spread.

Video laryngoscopy improves ProSeal™ laryngeal mask airway position by anesthesia residents: A randomized controlled, double-blind study

BackgroundThe insertion of ProSeal laryngeal mask airway (LMA) using a blind digital technique is difficult for inexperienced performers and malpositioning of the device can impair ventilation and may lead to complications. AimThis study aimed to compare the proper ProSeal LMA position inserted by anesthesia residents between video laryngoscopy-assisted and blind digital insertion techniques. MethodsA total of 138 patients aged 18–80 years, ASA I and II undergoing elective surgery, were randomly allocated to the digital or video laryngoscopy-assisted group. Anesthesia residents performed ProSeal LMA insertion. The primary outcome was the proportion of a proper LMA position evaluated by a blinded assessor using the fiber-optic scores. Secondary outcomes included first attempt success rate, duration of insertion, incidence of desaturation during insertion, peak airway and oropharyngeal leak pressure, gastric tube placement difficulty, hemodynamic disturbance, and airway complications at 1 and 24 h after surgery. ResultsPatients in the video laryngoscopy group demonstrated a significantly higher proportion of proper LMA position than those in the digital group (53/68 [78 %] vs. 24/67 [36 %]; RR 2.18 [95%CI 1.54–3.07]; P < 0.001). Using the video laryngoscopy-guided insertion improved the fiber-optic scores by 7.11 folds (95%CI 3.53–14.32; P < 0.001) compared with the digital technique. Patients in the video laryngoscopy group showed higher sealing pressure, easier gastric tube placement, but longer insertion time. There was no significant difference in the peak airway pressure, first-attempt success rate, hemodynamic changes, and airway complications between groups. No desaturation occurred during the study. ConclusionUsing a Macintosh-shaped blade video laryngoscope facilitates novice anesthesiologists in achieving improved ProSeal LMA positioning without compromising airway or hemodynamic complications. The optimal ProSeal LMA position also provides a higher oropharyngeal sealing pressure and easier gastric tube placement.

Tissue displacement assessment by ultrasound predicts peri-laryngeal leak after supraglottic device insertion (I-gel)

Background and aims Supraglottic airway devices (SADs) have revolutionized airway management during general anesthesia, and they fill the niche between the face mask and endotracheal tube in terms of both airway anatomy and degree of invasion. The aim of this study was assessment of peri-laryngeal leak after insertion of I- gel using ultrasound (US) pulse Doppler mode. Methods Hundred patients scheduled for elective surgery after I-gel placement were recruited. Airway leak pressure was detected by using closed circuit in anesthesia workstation and increasing the pressure to 20 mm Hg. Parameters were noted include, leak as observed in the monitor, leak as assessed using the US machine, fiberoptic visualization of the SAD and grading and end tidal CO2 (ETCO2). Results In ultrasound we have detected peri-laryngeal tissue displacement in 18 patients (18%) out of which 10 patients have grade 3 or 4 on fiberoptic examination (Fig. 2). Among these ten patients, eight patients have inadequate ventilation required reinsertion of I-gel. Conclusion Tissue displacement assessment by ultrasound can be used as a noninvasive alternative to predict leak following supraglottic device insertion (I-gel) placement with the added advantage of no interruption of ventilation.

Post-extubation use of high-flow nasal oxygenation induces upper airway leak and intrathoracic sepsis after successful Bentall procedure: A case report.

In recent few years, high-flow nasal oxygenation (HFNO) has been widely used for management of acute hypoxemic respiratory failure and during postextubation periods, including after endotracheal intubation general anesthesia (ETGA). However, HFNO generates positive pressure in the injured airway following removal of endotracheal tube may cause airway leaks. This is the first case report of severe airway leak syndrome following postextubation use of HFNO in surgical patients. This case report describes a 75-year-old female with critical aortic stenosis who underwent an emergency Bentall procedure. HFNO (flow rate of 45 L/min) was applied after weaning from mechanical ventilation and removal of the endotracheal tube. At 6 hours after HFNO application, subcutaneous emphysema in the neck bilaterally and face was noted, and the emphysema extended into the supraclavicular regions. The HFNO cannula was removed soon after and the patient was re-intubated with an endotracheal tube the following day due to progressive respiratory insufficiency. Unfortunately, the patient general condition deteriorated, as the subcutaneous air collections progressed into deep tissue infections of the neck, mediastinal abscesses, and left-sided empyema. Patient received surgical interventions repeatedly to drain the mediastinal abscess and empiric antimicrobial therapy was given. The patient passed away about 2 months later due to uncontrollable sepsis. Air leaks in the upper airway can occur during the use of post-extubation HFNO use, and the resulting subcutaneous emphysema can progress to severe intrathoracic infections in surgical patients who have a sternotomy wound. Therefore, HFNO-induced subcutaneous emphysema should be treated more aggressively in open thoracic or sternotomy surgeries to prevent the development of intrathoracic sepsis.

A rare cause of air-leak syndrome in a premature newborn: a case report

BackgroundPulmonary complications, such as airway leak syndrome, are common in preterm neonates; however, bronchial rupture is a rarely seen phenomenon.Case PresentationIn this case, we present a preterm newborn who developed pneumomediastinum and pneumothorax. The pneumothorax persisted, despite placement of a thorax tube, requiring a thoracotomy to detect and treat the bronchial rupture.ConclusionPhysicians should have a high suspicion of bronchial rupture in patients with persistent air leak syndrome, even after thorax tube placement and continuous negative pressure implementation.

Total dead space in children under general anesthesia.

Total dead space in children under general anesthesia.

Avaliação da pressão dos manguitos dos tubos endotraqueais em cães e gatos

Tracheal tube cuffs facilitate pulmonary ventilation and protect the lower airways from aspiration, but several complications can occur, especially when this pressure exceeds 30 cm H2O. The occurrence of hyperinflation of cuffs in dogs and cats was evaluated when inflation was performed without pressure measurement. After orotracheal intubation, the anesthetist inflated the cuff with a 5 ml syringe to obtain a pressure that he considered sufficient for tracheal sealing. A pressure test was performed to assess airway leakage. Cuff pressure was measured using a syringe designed to measure cuff pressure (AG Cuffill®). It should be noted that only 16.66% of the cuffs were within the established standard range. While 75% were below the minimum value and 8.33% were above the standard value.

Evaluation of Ambu-Aura-i laryngeal mask as a conduit for endotracheal intubation. A comparison with Air-Q intubating laryngeal airway in adult surgical patients

ABSTRACT Background Supraglottic airway devices (SGA) are used as primary devices or conduits for endotracheal intubation with normal or difficult airway. The purpose of this study was to assess how the Ambu-Aura-i laryngeal mask would act as a conduit for endotracheal intubation compared to the Air-Q Intubating Laryngeal airway in adult patients in operating room. Methods Fifty-four adult patients scheduled for elective procedures under general anaesthesia were divided into air-Q and Aura-i groups. The ease and time of insertion, the number of insertion attempts, the airway leak pressure, the duration of fiberoptic endotracheal intubation, the grade of the fibre-optic laryngoscopic view, and the time to remove the device were noted. Results Comparing the Aura-i group to the Air-Q group, the Aura-i group had a considerably shorter insertion time and a longer time to remove the device (28.1 ± 3.5 vs 32.7 ± 6.9 sec P-value = 00.4 and 40.7 ± 5.1 vs 32.0 ± 5.4 sec, P-value = 0.001; respectively). Both devices were comparable regarding the number of insertion attempts and the time to insert an endotracheal tube. Compared to the Air-Q group, the Aura-i group’s airway leak pressure was considerably greater (25.9 ± 3.9 vs 23.4 ± 4 CmH2O, respectively, P-value = 0.03). Both groups had comparable fibre-optic laryngoscopic view grades. Conclusion The Ambu-Aura-i laryngeal mask and the Air-Q intubating laryngeal airway are efficient conduits for fibre-optic endotracheal intubation in adults with Ambu-Aura-i Laryngeal mask exhibiting advantages in terms of device insertion time and use during mechanical ventilation.

Achieving Successful Extubation and Cost-Effective Recovery Following Anesthetic Airway Management in Supracarinal Tracheal Reconstruction Surgeries: A Retrospective Analysis.

Introduction From an anesthesiologist's perspective, perioperative concerns related to supracarinal tracheal reconstruction surgery include having uninterrupted smooth ventilation without any laryngeal edema, glottic dysfunction, and airway leak. Surgical concerns comprise various kinds of anastomotic dissections, fistulas to innominate arteries, and the esophagus. The most serious complication following tracheal surgery is anastomotic separation, which might manifest modestly as stridor, respiratory distress, and extremis. To avoid dire repercussions, prompt management and securing the airway are necessary.Against this background,we wanted tohighlight the importance of early extubation and discharge of supracarinal tracheal reconstruction patients from hospitals without any postoperative complications and with the least expenses possible, since mostof these patients have already undergone postintubation tracheal stenosis and prolonged intensive care unit stay, and have experienced significant financialburden incurring from preceding events. Methodology Medical records of allpatients admitted for tracheal reconstruction during the period from March 2019 toApril 2022(four years)were reviewed to collect patient demographic details, surgical descriptions, anesthesia data, records of pre-anesthetic evaluations, and postoperative details up until the hospital discharge. Results The most common reason for tracheal stenosis among our patients was post-intubation tracheal stenosis (PITS), which was seen in 8/13 patients (61.53%);4/13patients (30.76%)had stridorat rest and underwent emergency tracheostomy preoperatively immediately following admission to the hospital.The stenosis was situated at a median distance of 3 cm [interquartilerange (IQR): 0.5-7] from the true vocal cords or 7 cm (IQR: 3-9) from the carina. The median length of tracheal resection was 2 cm(IQR: 1-4).Weobserved that the mode ofinductionfor airway management was tracheostomytubein four patients (with 90% tracheal stenosis), placement of laryngeal mask airway (LMA) with spontaneous ventilationin four patients (with 75% tracheal stenosis), andsmall-size (#5-7.5sizes) endotracheal tube (ETT) placement in five patients (with less than 75% tracheal stenosis).The postoperative complicationnoted was bleeding from the operative site in 1/13 patients (7.6%); a 0% mortality rate was noted during the hospital stay and up until six months post-discharge. We noted that the median duration of postoperative hospitalizationwas five days (IQR: 2-15), and the total cost incurred by each patientwas less thanINR 85,000 (USD 1,000). Conclusion Our analysis revealed that all our patients were extubated in the operative room andshifted to the ward. In the "open airway phase",standard distal tracheal intubation and cross-field ventilation techniques, and tracheal suturing were facilitated by the apnoea-ventilation-apnoea technique. Both the techniques along with the emergency tracheostomies done in severe tracheal obstruction preoperatively and intraoperative anesthesia management with the insertion of LMA Supreme,maintained with spontaneous breathing techniques, offered potential advantages in the management ofsupracarinal tracheal reconstruction surgeries. The multidisciplinary teamwork along with close communication and good rapport with the surgical team was found to be the key factor in the fast-track extubation and recovery of these patients.

AutoFlow® (volume-guaranteed mode) versus volume-controlled ventilation for the laparoscopic surgery with BlockBuster supraglottic airway: A randomized controlled trial

Abstract Background and Aims: Supraglottic airway devices used in laparoscopic surgeries must be efficient to counter the increased peak airway pressure (PAWP) and airway leakage that can occur in laparoscopic surgeries. Hence, the implication of AutoFlow in ventilator strategy is propounded nowadays that facilitates low PAWP and high dynamic compliance to achieve targeted tidal volume and end-tidal carbon dioxide (ETCO2). BlockBuster™ Laryngeal mask furnishing minimum airway leak. The primary objective was to compare PAWP using the two modes of ventilation through the BlockBuster LMA after intubation, pneumoperitoneum, and Trendelenburg position. The secondary objective was to observe hemodynamic vitals. Methodology: In this single-center randomized controlled trial, we recruited 80 American Society of Anesthesiologists grade I and II adult patients undergoing elective laparoscopic surgeries. They were randomized by computer-generated method into two groups: volume-controlled AutoFlow® (VCAF) and volume-controlled (VC) group. Ventilation settings for both groups set to tidal volume 5–6 ml/kg of predicted body weight, positive end-expiratory pressure 5 cm H2O, I: E ratio 1:2, and respiratory rate 12–16/min to maintain targeted ETCO2 of 30–35 cm H2O. Intraabdominal pressure was set to 14 mmHg during pneumoperitoneum and 15° Trendelenburg position. Results: Mann–Whitney U-test for continuous variables and t-test for categorical variables. Data were presented as median (interquartile range). P &lt;0.05 was considered statistically significant. During laparoscopic surgeries with BlockBuster™ PAWP at pneumoperitoneum was (20 cm H2O vs. 27 cm H2O) and Trendelenburg position (19 cm H2O vs. 27 cm H2O) was significant lower with VCAF (AutoFlow® ventilation) than with VC (P &lt; 0.05). Conclusion: PAWP is significantly low in AutoFlow mode as compared to volume control mode with BlockBuster LMA. In addition, LMA BlockBuster provides good sealing pressure.

Comparison of Laryngeal tube suction II (LTS II) and Proseal laryngeal mask airway (PLMA) for controlled ventilation in anaesthetised and paralysed adult patients

Background: LTS II and PLMA are supraglottic devices that may be used for ventilation in patients with normal as well as difficult airways at risk of aspiration. Aim: Comparison of LTS II with PLMA during controlled ventilation in paralysed patients with respect to time to successful insertion, success rate of insertion, attempts at repositioning, airway leak pressure, ease of ventilation and Ryle’s tube insertion, fibreoptic laryngeal view and complications. Methods: Thirty patients were studied using a prospective, randomised cross-over design. Ethical committee clearance and informed consent were obtained from all patients. Anaesthesia was induced with propofol and fentanyl and neuromuscular blockade achieved with vecuronium. Patients were divided into two groups: Group LTS and Group PLMA. In each group, the first airway device was inserted, various parameters observed and then removed. The second airway device was then inserted and the same parameters noted. Anaesthesia was continued with the second device in position. Results: Success with insertion at first attempt and time to insertion were comparable with both devices [LTS II 27/30 (17.5 s) and PLMA 29/30 (15.5 s) respectively]. PLMA required repositioning in fewer patients and provided better fibreoptic view than LTS II. Ryle’s tube insertion failed in four patients with PLMA but in none with LTS II. No significant difference was found in the airway seal pressure [mean, PLMA (27 cm H2 O) and LTS II (26.4 cm H2 O)], ease of ventilation or overall complications. Conclusion: Insertion and ventilation are comparable with PLMA and LTS II. Ryle’s tube insertion is easier with LTS II but requires more repositioning attempts and does not provide a good view of the larynx

Effect of closed extension tube on preventing airway leakage during artificial airway clearance

Objective: To explore the role of closed extension tube in preventing airway leakage during artificial airway clearance. Methods: The test lung was connected with a ventilator for mechanical ventilation. The pressure parameters were set as 16/5, 20/6, 24/7, 28/8, 32/9 and 36/10 cmH2O(1 cmH2O=0.098 kPa), respectively. The circuit was connected with an open extension tube or a closed extension tube. The ventilator was set with different pressure parameters to observe the changes of airway pressure and tidal volume during airway clearance. Results: (1) The pressure parameters were set as 16/5, 20/6, 24/7, 28/8, 32/9 and 36/10 cmH2O, and the airway pressures (in cmH2O) of circuit connected with open extension tube were (15.94±0.27)/(4.81±0.04), (20.09±0.23)/(6.05±0.16), (23.89±0.41)/(6.94±0.06), (27.90±0.22)/(7.71±0.18), (31.92±0.13)/(8.74±0.12)and(35.65±0.31)/(9.72±0.07), respectively.Under the same ventilator pressure parameters, the airway pressures (in cmH2O) of circuit connected with close extension tube were (16.36±0.06)/(4.85±0.04), (20.54±0.26)/(6.44±0.12), (24.36±0.24)/(7.01±0.33), (28.69±0.25)/(8.07±0.08), (32.97±0.33)/(8.93±0.09), (37.34±0.29)/(9.75±0.08), respectively. The airway pressure of circuit connected with open extension tube was lower than that connected with closed extension tube(P<0.05);with the increase of the pressure setting of the ventilator, the difference of the airway pressure between the two extended tubes gradually increased. When the maximum inspiratory pressure of the ventilator was set 36 cmH2O, the difference reached 1.69 cmH2O. (2) The airway pressures (in cmH2O) dropped from (15.94±0.27)/(4.81±0.04), (20.09±0.23)/(6.05±0.16), (23.89±0.41)/(6.94±0.06), (27.90±0.22)/(7.71±0.18), (31.92±0.13)/(8.74±0.12), (35.65±0.31)/(9.72±0.07) to (13.42±0.4)/(3.15±0.14), (16.81±0.6)/(4.30±0.14), (20.22±0.5)/(5.48±0.45), (23.73±1.4)/(6.25±0.22), (24.78±0.7)/(7.13±0.21), (20.83±0.4)/(6.61±0.19)when the suction port of the open extension tube was opened (P<0.05);and the tidal volume (in L) also decreased from 0.328±0.004, 0.580±0.012, 0.621±0.003, 0.626±0.003, 0.615±0.003, 0.603±0.002 to 0.272±0.008, 0.416±0.051, 0.487±0.047, 0.396±0.116, 0.507±0.022, 0.508±0.079, respectively (P<0.05). The decrease of airway pressure and tidal volume gradually increased with the increase of ventilator setting pressure. When the ventilator setting parameter was 36/10 cmH2O, the decrease of airway inspiratory pressure was (14.82±0.51) cmH2O and the maximum reduction of tidal volume was (0.164±0.021)L. (3)The airway pressure (in cmH2O) was increased to(15.70±0.23)/(4.80±0.33), (19.01±0.81)/(5.71±0.34), (22.27±0.62)/(6.85±0.44), (25.35±2.09)/(7.94±0.16), (28.38±0.46)/(8.96±0.23), (33.34±0.71)/(9.71±0.25) when the suction tube was inserted from the suction port of the open extension tube in the open state, and the tidal volume (in L) was increased to 0.340±0.016, 0.563±0.020, 0.571±0.030, 0.556±0.026, 0.514±0.021, 0.512±0.031 as well.The airway pressure and tidal volume of the ventilation circuit were higher than those in the open state, but still lower than those in the closed state. Compared with the closed state of the suction port, the maximum pressure drop and tidal volume decrease were (3.53±0.46) cmH2O and (0.101±0.011) L, respectively. (4) The pressure of the ventilator was set between 16/5 cmH2O to 36/10 cmH2O. The airway pressure (in cmH2O) was decreased from (16.26±0.04)/(4.85±0.04), (20.74±0.15)/(6.42±0.11), (25.09±0.31)/(7.10±0.13), (29.38±0.24)/(8.17±0.09), (33.80±0.16)/(9.02±0.17), (37.89±0.19)/(9.83±0.07) to(16.36±0.06)/(4.85±0.04), (20.54±0.26)/(6.44±0.12), (24.36±0.24)/(7.01±0.33), (28.69±0.25)/(8.07±0.08), (32.97±0.33)/(8.93±0.09), (37.34±0.29)/(9.75±0.08), respectively during the insertion of the suction tube from the suction port of the closed extension tube, and the tidal volume (in L) was decreased from0.361±0.005, 0.592±0.003, 0.631±0.001, 0.642±0.007, 0.633±0.007, 0.626±0.08 to 0.335±0.005, 0.588±0.008, 0.631±0.002, 0.638±0.004, 0.628±0.004, 0.618±0.005.The maximum pressure change of the ventilation circuit was (0.83±0.27) cm H2O and the maximum tidal volume change was (0.008±0.006)L. The changes of airway pressure and tidal volume were significantly lower than those of ventilation circuit connected with open extension tube under the same pressure parameters. Conclusion: The connection of closed extension tube in mechanical ventilation circuit can reduce the airway leakage during artificial airway clearance, which is worthy of clinical recommendation.

Baska Mask in Patients undergoing Elective Breast Surgeries under General Anaesthesia: An Observational Study

Introduction: Supraglottic airway devices are newer safer alternative devices to endotracheal intubation during General Anaesthesia. The Baska mask is a novel third generation Supraglottic Airway Devices (SADs) with an added advantage of silicon self-recoiling, non inflatable cuff. Postgraduate trainees will need hands on training in all available airway securing devices and have experience in using the Baska mask and also complications associated with it. Aim: To assess the successful insertion of Baska mask by postgraduate trainees, and its placement in 50 low-risk female patients posted for breast surgeries, and also to determine the correct placement using fibreoptic bronchoscope. Materials and Methods: The present study was an observational study conducted at Kidwai Cancer Institute, Bangalore, Karnataka, India from January 2019 to January 2020 in which a total of 50 study participants were selected, and Baska mask was inserted by postgraduate trainees in all patients. The placement of the mask was assessed by fibreoptic bronchoscope using Brimacombe scoring. Ease of insertion, time required for insertion and attempts required for the insertion of the mask was assessed along with postoperative complications. Student’s t-test and Chisquare test were used to study the parameters on continuous scale and categorical scale, respectively. Results: The mean age of the study population was 46.9±7.8 years. The overall success rate for device insertion was 96%, while the success rate for the first insertion attempt was 60%. The device was ‘easy’ to insert among 48% of patients, and mean time required for insertion was 20.54±10.7 sec. The mean airway leak pressure was 39.17 cmH2 O. Postoperative complications were notably less with sore throat seen in 20.8%, and the incidence of other side-effects like laryngospasm was nil. Conclusion: Baska mask can be successfully and safely used by postgraduate trainees as a tool for securing the airway. As learning curve for Baska mask is short, it can be used safely for training postgraduate trainees and to improve their expertise in using the Baska mask.

Noninvasive ventilation in children: A review for the pediatric anesthesiologist.

Preserving adequate respiratory function is essential in the perioperative period. Mechanical ventilation with endotracheal intubation is widely used for this purpose. In select patients, noninvasive ventilation (NIV) may be an alternative to invasive ventilation or may complement respiratory management. NIV is used to provide ventilatory support and increase gas exchange at the alveolar level without the use of an invasive artificial airway such as an endotracheal tube or tracheostomy. NIV includes both continuous positive airway pressure (CPAP) and noninvasive positive pressure ventilation. Indications for NIV range from acute hypoxic respiratory failure in the intensive care unit or the emergency department, to chronic respiratory failure in patients with neuromuscular disease with nocturnal hypoventilation. In the perioperative setting, NIV is commonly applied as CPAP, and bilevel positive airway pressure (BPAP). There are limited data on the role of NIV in children in the perioperative setting, and there are no clear guidelines regarding optimal timing of use and pressure settings of perioperative NIV. Contraindications to the use of NIV include reduced level of consciousness, apnea, severe respiratory distress, and inability to maintain upper airway patency or airway protective reflexes. Common problems encountered during NIV involve airway leaks and asynchrony with auto-triggering. High-flow nasal oxygen (HFNO) has emerged as an alternative to NIV when trying to decrease the work of breathing and improve oxygenation in children. HFNO delivers humidified and heated oxygen at rates between 2 and 70L/min using specific nasal cannulas, and flows are determined by the patient's weight and clinical needs. HFNO can be useful as a method for preoxygenation in infants and children by prolonging apnea time before desaturation, yet in children with decreased minute ventilation or apnea HFNO does not improve alveolar gas exchange. Clinicians experienced with these devices, such as pediatric intensivists and pulmonary medicine specialists, can be useful resources for the pediatric anesthesiologist caring for complex patients on NIV.

A comparative study on the perfomance between I-gel® and Classic laryngeal mask airway in anaesthetized spontaneously breathing patients

The classic Laryngeal Mask Airway (c-LMA) is a first generation supraglottic airway device with an inflatable cuff forming a low pressure seal around the laryngeal inlet and permitting ventilation. I-gel is a supraglottic airway device made of thermoplastic elastomer which is soft gel-like and transparent. Unlike the classic LMA(c-LMA), I-gel does not have an inflatable cuff. In view of this, the present study was undertaken to compare the performance of the two supraglottic airway devices in spontaneously breathing adult patients posted for elective surgeries under general anesthesia.To compare the ease of insertion, number of insertion attempts, time for insertion, airway leak pressure, hemodynamic changes as well as perioperative complications such as cough sore throat between patients using the two devices.Sixty patients admitted in SRM medical college and research center scheduled for various elective surgical procedures under general anesthesia belonging to ASA class I and II were included in the study. They were randomly divided into two groups of 30 each using a random number generator. In group I, I-gel supraglottic airway device was used and in Group 2 classic laryngeal mask airway was used. Data was collected using a questionair containing socio-demographic details, details regarding performance of the device as well as hemodynamic changes and perioperative complications.The insertion was easy in 25 patients (83.3%) in group I, while in group II 15 patients (50%) had easy insertion. P=0.0 1781. The mean time of insertion for I-gel was (20. 17± 3 .91 seconds) which was significantly shorter compared to c-LMA (26.80 ±7.24 seconds) (P&amp;#60;0.001).There was no statistically significant difference between the devices with respect to number of attempts of insertion. Even though the airway leak pressure is not statically significant, the mean oropharyngeal leak pressure for I-gel was 20.40±5.68 (mm Hg), which was higher than c-LMA 18.73±5.06 (mm Hg), which is well within the normal limits to prevent aspiration. There were no statistically significant differences in hemodynamic changes. No Blood staining was seen after removal of device in I-gel group where it was observed in 2 (7%) patients in c- LMA group. Post removal cough was more in c -LMA (13 .3%) than l-gel (P= 0.04 SS*). Pharyngo-Laryngeal morbidity was more with classic LMA. Sore throat was more with the classic LMA (13 .3%) when compared to I-gel group (3%).We conclude that I-gel is a better airway when compared to c-LMA with respect to ease of insertion, shorter duration for insertion, adequate oropharyngeal seal with lesser pharyngo-laryngeal morbidity and less incidence of airway trauma.

I gel versus endotracheal intubation for percutaneous tracheostomies: a randomised study to ascertain amicable approach

Background: Percutaneous tracheostomy or percutaneous dilation tracheostomy (PDT) is an airway management procedure routinely performed in critically ill patients, requiring prolonged ventilation. It is safely performed bedside by anaesthesiologist/intensivist in ICUs. Complications as endotracheal tube (ET) damage, loss of airway due to accidental extubation and piercing of guide wire through ET tube during procedure has led to exploration of safer/effective and viable airway alternatives while performing the procedures.Methods: In this study we randomised 60 patients to group E (ET) and group I (I gel) 30 each and studied ease of carrying out procedure and associated complication rates in both groups.Results: In ET group (group E), 9% of patients suffered with potentially catastrophic complications, e.g. loss of airway, inadequate ventilation of lungs, haemorrhage, airway leak due to ET tube cuff rupture and accidental extubation. In ETT group there was incidence of 18% cuff puncture by guide wire (p=0.025) and 3% accidental tracheal extubation. Group I witnessed lower incidence of haemorrhage (3%) and the incidence of guide wire piercing airway device was nil. Group I also demonstrated better hemodynamic stability attributed to lesser tissue trauma and airway manipulation.Conclusions: This study demonstrates enhanced safety with usage of I gel for PCDT, with less complication, better hemodynamic stability and shorter procedure duration.

Randomized crossover trial to compare driving pressures in a closed-loop and a conventional mechanical ventilation mode in pediatric patients.

In mechanically ventilated patients, driving pressure (ΔP) represents the dynamic stress applied to the respiratory system and is related to ICU mortality. An evolution of the Adaptive Support Ventilation algorithm (ASV® 1.1) minimizes inspiratory pressure in addition to minimizing the work of breathing. We hypothesized that ASV 1.1 would result in lower ΔP than the ΔP measured in APV-CMV (controlled mandatory ventilation with adaptive pressure ventilation) mode with physician-tailored settings. The aim of this randomized crossover trial was therefore to compare ΔP in ASV 1.1 with ΔP in physician-tailored APV-CMV mode. Pediatric patients admitted to the PICU with heterogeneous-lung disease were enrolled if they were ventilated invasively with no detectable respiratory effort, hemodynamic instability, or significant airway leak around the endotracheal tube. We compared two 60-minperiods of ventilation in APV-CMV and ASV 1.1, which were determined by randomization and separated by 30-minwashout periods. Settings were adjusted to reach the same minute ventilation in both modes. ΔP was calculated as the difference between plateau pressure and total PEEP measured using end-inspiratory and end-expiratory occlusions, respectively. There were 26 patients enrolled with a median age of 16 (9-25 [IQR]) months. The median ΔP for these patients was 10.4 (8.5-12.1 [IQR]) and 12.4 (10.5-15.3 [IQR]) cmH2O in the ASV 1.1 and APV-CMV periods, respectively (p < .001). The median tidal volume (VT) selected by the ASV 1.1 algorithm was 6.4 (5.1-7.3 [IQR]) ml/kg and RR was 41 (33 50 [IQR]) b/min, whereas the median of the same values for the APV-CMV period was 7.9 (6.8-8.3 [IQR]) ml/kg and 31 (26-41[IQR]) b/min, respectively. In both ASV 1.1 and APV-CMV modes, the highest ΔP was used to ventilate those patients with restrictive lung conditions at baseline. In this randomized crossover trial, ΔP in ASV 1.1 was lower compared to ΔP in physician-tailored APV-CMV mode in pediatric patients with different lung conditions. The use of ASV 1.1 may therefore result in continued, safe ventilation in a heterogeneous pediatric patient group.

AutoFlow\xae versus volume-controlled ventilation for laparoscopic gynecological surgery using LMA\xae ProSeal\u2122: a randomized controlled trial

BackgroundDuring laparoscopic gynecological surgery, increased peak airway pressure (PAWP) can cause airway leak upon ventilation with the LMA® ProSeal™. We hypothesized that compared with the use of volume-controlled ventilation (VCV), the use of the AutoFlow® mode would decrease PAWP and airway leak during laparoscopic gynecological surgery with LMA ProSeal.MethodsThis single-center, randomized, controlled trial allocated 80 adult women undergoing elective laparoscopic gynecological surgery to one of two groups, namely, the AutoFlow group or the VCV group. Ventilation settings for both groups were 8 ml/kg of tidal volume and 5 cmH2O of positive end-expiratory pressure, and respiratory rate was adjusted to maintain end-tidal carbon dioxide at 35–40 mmHg. Airway leak, PAWP, and other ventilatory parameters and vital signs were recorded at four timepoints (1, 1 min after insertion of the gastric tube; 2, 2 min after intravenous administration of rocuronium 0.6–0.8 mg/kg; 3, 1 min after initiation of pneumoperitoneum; and 4, 1 min after changing to the Trendelenburg position). The primary outcome was PAWP during pneumoperitoneum and in the Trendelenburg position, whereas the secondary outcomes included PAWP at other timepoints and airway leak development. We used the Mann–Whitney U test for PAWP and Fisher’s exact test for comparing airway leak among the groups.ResultsData from 40 patients in the AutoFlow group and 39 in the VCV group were used for analysis. PAWP at pneumoperitoneum pressure and in the Trendelenburg position was significantly lower in the AutoFlow group than in the VCV group [median (interquartile range), 16 (15–18) cmH2O vs. 18 (17–19) cmH2O; P < 0.001]. Similarly, patients in the AutoFlow group showed lower PAWP at the other three timepoints measured. Airway leak occurred in four patients in the AutoFlow group and in two patients in the VCV group; however, this incidence was not significantly different (P = 0.68).ConclusionsEven though AutoFlow ventilation decreased PAWP, it did not reduce the incidence of airway leak compared with VCV during laparoscopic gynecological surgery with the LMA ProSeal.Trial registrationUMIN Clinical Trials Registry, identifier UMIN000023173.

Aspergillus fumigatus Strain-Specific Conidia Lung Persistence Causes an Allergic Broncho-Pulmonary Aspergillosis-Like Disease Phenotype.

ABSTRACTAspergillus fumigatus is a filamentous fungus which can cause multiple diseases in humans. Allergic broncho-pulmonary aspergillosis (ABPA) is a disease diagnosed primarily in cystic fibrosis patients caused by a severe allergic response often to long-term A. fumigatus colonization in the lungs. Mice develop an allergic response to repeated inhalation of A. fumigatus spores; however, no strains have been identified that can survive long-term in the mouse lung and cause ABPA-like disease. We characterized A. fumigatus strain W72310, which was isolated from the expectorated sputum of an ABPA patient, by whole-genome sequencing and in vitro and in vivo viability assays in comparison to a common reference strain, CEA10. W72310 was resistant to leukocyte-mediated killing and persisted in the mouse lung longer than CEA10, a phenotype that correlated with greater resistance to oxidative stressors, hydrogen peroxide, and menadione, in vitro. In animals both sensitized and challenged with W72310, conidia, but not hyphae, were viable in the lungs for up to 21 days in association with eosinophilic airway inflammation, airway leakage, serum IgE, and mucus production. W72310-sensitized mice that were recall challenged with conidia had increased inflammation, Th1 and Th2 cytokines, and airway leakage compared to controls. Collectively, our studies demonstrate that a unique strain of A. fumigatus resistant to leukocyte killing can persist in the mouse lung in conidial form and elicit features of ABPA-like disease.IMPORTANCE Allergic broncho-pulmonary aspergillosis (ABPA) patients often present with long-term colonization of Aspergillus fumigatus. Current understanding of ABPA pathogenesis has been complicated by a lack of long-term in vivo fungal persistence models. We have identified a clinical isolate of A. fumigatus, W72310, which persists in the murine lung and causes an ABPA-like disease phenotype. Surprisingly, while viable, W72310 showed little to no growth beyond the conidial stage in the lung. This indicates that it is possible that A. fumigatus can cause allergic disease in the lung without any significant hyphal growth. The identification of this strain of A. fumigatus can be used not only to better understand disease pathogenesis of ABPA and potential antifungal treatments but also to identify features of fungal strains that drive long-term fungal persistence in the lung. Consequently, these observations are a step toward helping resolve the long-standing question of when to utilize antifungal therapies in patients with ABPA and fungal allergic-type diseases.