Tracheal Tube Group Research Articles

Chula Formula is recommended in Estimating the Length of Tracheal Tube Insertion in Patients Receiving Mechanical Ventilation in Intensive Care Units in the Absence of Chest X-Ray

Background: Chest X-Ray (CXR) is one of the most effective ways of confirming the length of the tracheal tube (TT) insertion. However, some intensive care unit in developing countries has no sufficient facilities. This study aims to evaluate the accuracy of TT length insertion using the Chula formula and Colombian formula in patients receiving mechanical ventilation in intensive care units. Methods: This study is a comparative observational study of 50 adults in the Intensive care unit, divided into two groups. Group A used the Chula formula for TT length insertion (n= 25) and Group B used the Colombian formula (n= 25). The TT length insertion accuracy was evaluated using radiological parameters. Statistical analysis used: Data were analyzed statistically using the T-test and Chi-square test. Result: The Chula formula is significantly more precise than the Colombian formula in estimating the length of TT insertion based on the radiographic parameters of the TT length insertion right midway between the medial tip of the clavicle and TT located in the T3 or T4 vertebrae (p <0.05), but not significantly different in the two other parameters. Conclusion: Both the Chula formula and the Colombian formula can estimate the length of TT insertion in adult patients. However, the Chula formula is more recommended in the length of TT insertion and benefit in the ICU with insufficient CXR.

Safety and efficacy of a novel double-lumen tracheal tube in neonates with RDS: A prospective cohort study.

The purpose of this study was to assess the safety and efficacy of a new double-lumen tracheal tube for neonates, with a conventional tracheal tube as a control. Newborns with respiratory distress syndrome (RDS) requiring endotracheal intubation admitted to the tertiary neonatal intensive care unit (NICU) of Qujing Maternal and Child Healthcare Hospital in Yunnan Province between March 2021 and May 2022 were enrolled in this prospective cohort study. Outcome indicators related to effectiveness included mainly the number of intubations, duration of ventilation, duration of oxygenation, and length of stay; safety indicators included any clinical adverse effects during and after intubation. Appropriate stratified and subgroup analyses were performed according to the purpose of intubation, gestational age, and whether the drug was administered via endotracheal tube. A total of 101 neonates were included and divided into two groups based on the choice of tracheal tube: the conventional (n = 50) and new (n = 51) tracheal tube groups. There was no statistical difference between the two groups in terms of adverse effects during and after intubation (p > 0.05). In neonates who were mechanically ventilated without endotracheal surfactant therapy or newborns receiving InSurE technique followed by non-invasive ventilation, no significant differences were found between the two groups regarding any of the efficacy indicators (p > 0.05). However, for neonates on invasive mechanical ventilation, the new tracheal tube allowed for a significant reduction in the duration of mechanical ventilation (96.50[74.00, 144.00] vs. 121.00[96.00, 196.50] hours, p = 0.037) and total ventilation (205.71 ± 80.24 vs. 277.56 ± 117.84 h, p = 0.027), when used as a route for endotracheal drug delivery. Further analysis was performed according to gestational age for newborns requiring intratracheal surfactant administration during mechanical ventilation, and the data showed that for preterm infants, the new tracheal tube not only shortened the duration of mechanical ventilation (101.75 ± 39.72 vs. 155.50 ± 51.49 h, p = 0.026) and total ventilation (216.00 ± 81.60 vs. 351.50 ± 113.79 h, p = 0.010), but also demonstrated significant advantages in reducing the duration of oxygen therapy (9.75 ± 6.02 vs. 17.33 ± 8.43 days, p = 0.042); however, there was no statistical difference in efficacy outcomes between the two groups in full-term infants (p > 0.05). The efficacy and safety of this new tracheal tube are promising in neonates with RDS, especially those requiring surfactant administration via a tracheal tube during mechanical ventilation. Given the limitations of this study, however, the clinical feasibility of this catheter needs to be further confirmed in prospective randomized trials with larger sample sizes. http://www.chictr.org.cn/showproj.aspx?proj=122073.

Comparison of a polyvinyl chloride tube with a wire-reinforced tube for tracheal intubation through the SaCoVLM video laryngeal mask airway: protocol for a randomised controlled study

IntroductionThe SaCoVLM is a new type of video intubating laryngeal mask airway (LMA), and it is the first LMA to realise continuous visual monitoring. There is a lack of studies...

The Impact of Different Ventilatory Strategies on Clinical Outcomes in Patients with COVID-19 Pneumonia.

Introduction: The aim was to investigate the impact of different ventilator strategies (non-invasive ventilation (NIV); invasive MV with tracheal tube (TT) and with tracheostomy (TS) on outcomes (mortality and intensive care unit (ICU) length of stay) in patients with COVID-19. We also assessed the impact of timing of percutaneous tracheostomy and other risk factors on mortality. Methods: The retrospective cohort included 868 patients with severe COVID-19. Demographics, MV parameters and duration, and ICU mortality were collected. Results: MV was provided in 530 (61.1%) patients, divided into three groups: NIV (n = 139), TT (n = 313), and TS (n = 78). Prevalence of tracheostomy was 14.7%, and ICU mortality was 90.4%, 60.2%, and 30.2% in TT, TS, and NIV groups, respectively (p < 0.001). Tracheostomy increased the chances of survival and being discharged from ICU (OR 6.3, p < 0.001) despite prolonging ICU stay compared to the TT group (22.2 days vs. 10.7 days, p < 0.001) without differences in survival rates between early and late tracheostomy. Patients who only received invasive MV had higher odds of survival compared to those receiving NIV in ICU prior to invasive MV (OR 2.7, p = 0.001). The odds of death increased with age (OR 1.032, p < 0.001), obesity (1.58, p = 0.041), chronic renal disease (1.57, p = 0.019), sepsis (2.8, p < 0.001), acute kidney injury (1.7, p = 0.049), multiple organ dysfunction (3.2, p < 0.001), and ARDS (3.3, p < 0.001). Conclusions: Percutaneous tracheostomy compared to MV via TT significantly increased survival and the rate of discharge from ICU, without differences between early or late tracheostomy.

Comparison of gastric insufflation using LMA-supreme and I-gel versus tracheal intubation in laparoscopic gynecological surgery by ultrasound: a randomized observational trial

BackgroundThe application of bedside ultrasound to evaluate gastric content and volume can assist in determining aspiration risk. Applying positive pressure ventilation via supraglottic airway devices (SAD) can result in a degree of gastric insufflation. This study assessed and compared the antral cross-sectional area (CSA) in patients undergoing laparoscopic gynecological surgery when managed with different SAD.MethodsOne hundred American Society of Anesthesiologists I or II female patients were assessed for inclusion in this study and divided into three groups of different ventilation devices. Patients were randomly allocated into three groups to receive LMA-Supreme (Group S), I-gel (Group I) or tracheal tube (Group T). The primary outcome was the antral cross-sectional area and secondary outcomes included haemodynamic parameters and postoperative morbidity such as sore throat, hoarseness, dry throat, nausea and vomiting.ResultsThe antral CSA was not significantly different among three groups before induction (P = 0.451), after induction (P = 0.456) and at the end of surgery (P = 0.195). The haemodynamic variables were significantly higher in the tracheal tube group than in the LMA-Supreme and I-gel groups after insertion (P < 0.0001) and after removal (P < 0.01). Sore throat was detected in none in the I-gel group compare to two patients (6.7%) in the LMA-Supreme group and fifteen patients (50%) in the tracheal tube group. Hoareness was detected in one (3.3%) in the I-gel group compare to two patients (6.7%) in the LMA-Supreme group and eleven patients (36.7%) in the tracheal tube group.ConclusionsThe SADs do not cause obvious gastric insufflation. Thus, LMA-Supreme and I-gel can be widely used as alternative to endotracheal intubation for the short laparoscopic gynecological surgery.Trial registrationThis trial was registered at the Chinese Clinical Trial Registry (ChiCTR1800018212, data of registration, September 2018).

Flexometallic versus RAE Endotracheal Tube in Cleft Lip and Palate Surgery

Aim and Objectives: The present study was carried out with an objective to evaluate ease of insertion of catheter and suctioning through Flexo-metallic tube versus Ring Adair Elwin (RAE) tube, to know the incidence of kinking of RAE tube and to note down the endo-bronchial placement of Flexo-metallic versus RAE tube and surgeon’s comfort zone. Methods: A prospective observational randomized study was conducted on 60 ASA grade I and II pediatric patients of age group 4 month to 16 years undergoing cleft lip and palate surgeries. Patients were randomly allocated in two groups of 30 each. Group R: intubated with RAE South pole tube and group F: intubated with flexo-metallic tube. The ease of insertion of suction catheter, ease of suctioning of secretions, refixation required, kinking of tracheal tube, incidence of displacement, airway complications and surgeons’ feedback- Comfort zone were noted. Results: The ease of suctioning through lumen of Tracheal tube was easier in group ‘F’ as compared to RAE tube. No kinking of tracheal tube was found in any group. The displacement of tracheal tube was observed in 2 patients in group ‘R’. Refixation of tracheal tube was required in 2 patients in group ‘R’. Bronchospasm and cough was noted in 1 patient in group ‘R’. No variations in vitals (e.g. blood pressure and heart rate) were observed in any group. Surgical team was comfortable in both groups but more so with Flexo-metallic tracheal tube group. On extubation we found retained secretions at distal portion of RAE tube in 2 patients. Conclusion : Flexometallic tracheal tube provides advantage of easy suctioning of tracheal secretions. Do not kink in mouth gag of surgical field, provides better airway security and stability, less intra-operative manipulation by anaesthetist, less airway complications, provides better surgical field.

Clinical Comparison of I-Gel Supraglottic Airway Device and Cuffed Endotracheal Tube for Pressure-Controlled Ventilation During Routine Surgical Procedures.

Recently, there has been a trend favouring the use of supraglottic airway devices over endotracheal tubes (ETT) during short surgical procedures. In this study, we are going to assess the suitability of one such supraglottic airway device, i-gel, for pressure-controlled ventilation (PCV) during routine surgical procedures. The airway management for 60 patients was done with either i-gel (Group I) or cuffed tracheal tube (Group E) for this prospective, randomised, double-blinded study. Insertion time, number of attempts, ease of insertion and haemodynamic monitoring were recorded before, during and after insertion of these devices. Airway leak tests, leak volume and leak fraction were measured at 15, 20 and 25 cm H2O PCV, and pharyngolaryngeal morbidity was evaluated postoperatively. I-gel is easier to insert than a tracheal tube (p=0.0056). The increase in heart rate and MAP was higher following insertion of tracheal tube in the first few minutes (p<0.001) and subsequently became comparable between the two groups. The leak volume and leak fraction between the two groups were comparable at 15 cm H2O PCV, but significant difference was seen at 20 and 25 H2O PCV between the two groups (p=0.232, p<0.001, p<0.001). Thirty minutes later, the leak volume and leak fraction between groups were comparable at 15 cm H2O PCV (p=0.495, p=0.104) but not at 20 and 25 H2O PCV (p<0.001, p<0.001). Pharyngolaryngeal morbidity was significantly lesser in the i-gel group. I-gel provides a reasonable alternative to cuffed ETT for pressure-controlled ventilation provided the pressures can be limited to 15 to 20 cm H2O.

Efficacy of a type of endotracheal tube of extended with terminal swelling and resistance bending pressure for airway management during mechanical ventilation in children in prone position

Objective To evaluate the efficacy of a type of endotracheal tube of extended with terminal swelling and resistance bending pressure for airway management during mechanical ventilation in children in prone position. Methods Sixty pediatric patients with cerebral palsy of both sexes, aged 3-7 yr, weighing 11-23 kg, of American Society of Anesthesiologists physical statusⅠor Ⅱ, scheduled for elective selective functional posterior rhizotomy, were randomly allocated into 2 groups (n=30 each) using a random number table: endotracheal tube of extended with terminal swelling and resistance bending pressure group (group E) and reinforced tracheal tube group (group C). After induction of anesthesia, the type of endotracheal tube of extended with terminal swelling and resistance bending pressure was inserted in group E, and the reinforced endotracheal tube was inserted in group C. The tidal volume, minute ventilation, dynamic lung compliance, arterial oxygen saturation and end-tidal pressure of carbon dioxide in pressure-controlled ventilation mode were recorded in the two groups.Tube shedding caused by using of the extended tube was recorded during operation.Blood samples were collected from the femoral artery for blood gas analysis. Results Compared with group C, the tidal volume and minute ventilation were significantly increased (P 0.05). Compared with the value before anesthesia, no significant change was found in pH value, arterial oxygen partial pressure and partial pressure of arterial carbon dioxide at the end of operation in the two groups (P>0.05). In group C, the extended tube was used in 3 patients, and among the 3 cases, one patient developed tube shedding which was treated immediately. Conclusion The type of endotracheal tube of extended with terminal swelling and resistance bending pressure provides better efficacy than the reinforced endotracheal tube when used for airway management during mechanical ventilation in children in prone position. Key words: Intubation, intratracheal; Respiration, artificial; Prone position; Child

A prospective, randomized comparative study for use of proseal laryngeal mask airway as an alternative to endotracheal intubation for airway management in children under general anesthesia

Introduction: Proseal laryngeal mask airway (PLMA) which is an upgraded modification of classic LMA, incorporating a gastric drainage tube lateral to the main airway tube which permits the regurgitated liquid gastric contents to bypass the glottis and prevents pulmonary aspiration. A prospective randomized interventional comparative study was performed to compare the efficiency of PLMA with a tracheal tube (TT) in pediatric patients with respect to number of attempts to placement of devices, hemodynamic responses and perioperative complications. Material and Methods: Sixty children, ASA physical status I and II weighing 10-20 kg between 2 and 8 years of age group of either sex undergoing elective infraumblical surgeries of 30-60 minutes duration, randomly divided into two group of 30 patients each. All patients were premedicated with IV midazolam and glycopyrrolate. General anesthesia with caudal epidural analgesia was given in all cases. IV propofal and sevoflurane was used for inducing general anesthesia. PLMA was inserted in group I and tracheal tube (TT) in patients of group II. In all cases after PLMA / TT insertion; caudal epidural analgesia was given and general anesthesia (GA) was maintained with O2, N2O and sevoflurane. Results: Ease of insertion was comparable in both the groups. There were no significant differences in mean oxygen saturation SpO2 (%) and end tidal carbon dioxide (ETCO2)) levels recorded at different time intervals between the two groups. However, highly significant changes in hemodynamic parameters were observed in the TT group. Complications such as nausea and vomiting (3.33%), sore throat (2%) and coughing (26.66%) were observed in the TT group. Conclusion: We concluded that PLMA could be used as an effective and safe airway device in children alternative to TT undergoing general anesthesia. Keywords: General anesthesia, Hemodynamic response, Paediatric, Proseal laryngeal mask airway, Tracheal tube

Comparison of a Supraglottic Gel Device and an Endotracheal Tube in Keratoplasty Performed Under General Anesthesia: A Randomized Clinical Trial.

To assess the safety of a laryngeal mask (i-gel) in keratoplasty performed under general anesthesia. Patients with indications for keratoplasty (n = 110) were enrolled in a prospective study and randomly assigned to the i-gel (n = 55; 30 lamellar keratoplasty and 25 penetrating keratoplasty) or tracheal tube group (n = 55; 29 lamellar keratoplasty and 26 penetrating keratoplasty). Perioperative complications and the recovery time were compared between the 2 groups using the t test or χ(2) test. Contraindications to elective use of the laryngeal mask airway (esophageal reflux, extreme obesity, oropharyngeal pathology, or expected difficult intubation) and expected difficult intubation were excluded. No surgical perioperative complications were reported in either group. There was a significantly greater incidence of coughing at extubation and/or after extubation in the tracheal group (40/55; 73%) than in the laryngeal mask group (3/55; 5%) (P < 0.001). The recovery time was shorter in the i-gel group (80 minutes; 95% confidence interval, 75-86) compared with that in the tracheal tube group (88 minutes; 95% confidence interval, 82-95) (P = 0.03). There were no significant differences in the incidence of sore throat and hoarseness between both devices. The use of i-gel for keratoplasty under general anesthesia appears to be safe, reduces the risk of potential ocular hypertension during recovery, and saves recovery time.

Comparison between i‐gel and endotracheal tube in corneal grafts: a randomized clinical trial

PurposeTo assess the safety of the laryngeal mask I‐Gel® in keratoplasty (KP) performed under general anaesthesia.MethodsPatients with indications for KP (n = 110) were enrolled in a prospective study and randomly assigned to I‐Gel® (n = 55; 30 lamellar KP and 25 penetrating KP) or tracheal tube (n = 55; 29 lamellar KP and 26 penetrating KP). Peri‐operative complications and recovery time were compared between two groups using t‐test or χ2 test. Contraindications to elective use of the laryngeal mask airway were exclusion criteria (oesophageal reflux, extreme obesity, oropharyngeal pathology, expected difficult intubation).ResultsNo surgical peri‐operative complications were reported in either group. There was a significantly greater incidence of coughing at extubation and after extubation in the tracheal group (25/55; 45%) than in the laryngeal mask group (3/55; 5%) (p &lt; 0.001). Recovery time was shorter in the I‐Gel® group (80 min; 95%CI [75–86]) compared with the tracheal tube group (88 min; 95%CI [82–95]) (p = 0.03). There were no significant differences in the incidence of sore throat and hoarseness between the two devices.ConclusionsThe use of I‐Gel® for keratoplasty under general anaesthesia is safe, reduces the risk of potential ocular hypertension during recovery and saves recovery time.

Reliability of gas sampling from distal end of tracheal tube for PETCO2 monitoring in neonates

Objective To evaluate the reliability of gas sampling from the distal end of the tracheal tube for partial pressure of end-tidal CO2(PETCO2)monitoring in neonates. Methods A total of 50 full-term neonates, scheduled for elective abdominal surgery under general anesthesia, aged 1-28 days, weighing 2.55-4.00 kg, of ASA physical status Ⅰ or Ⅱ, were randomly divided into 2 groups(n=25 each)using a random number table: gas samples collected from proximal end of tracheal tube group(group P)and gas samples collected from distal end of tracheal tube group(group D). Epidural catheters of 1 mm in external diameter were used.One end of the catheter was connected to a tube for carbon dioxide sampling, and the other end was inserted into the endotracheal tube and advanced toward the distal hole of the tube.At 15 min of mechanical ventilation, blood samples were collected from the radial artery for record of PETCO2 and for blood gas analysis.Consistency test was performed between PETCO2 and partial pressure of arterial CO2(PaCO2). Results PETCO2 was significantly lower than PaCO2 in the two groups.There was no significant difference in PaCO2between the two groups.PETCO2 was significantly higher in group D than in group P. Kappa was significantly higher in group D than in group P. Conclusion Gas sampling from the distal end of the tracheal tube is more reliable than gas sampling from the proximal end in monitoring PETCO2 in the neonates. Key words: Intubation, intratracheal; Carbon dioxide; Arteries; Monitoring, intraoperative; Infant, newborn

The haemodynamic and ventilatory responses with I-gel, laryngeal mask airway and tracheal intubation during laparoscopic cholecystectomy

Background: Despite use of adequate medications and techniques, tracheal intubation induces haemodynamic stress response, which can be minimized by using supraglottic airway devices instead of tracheal tube in elective surgical cases with adequate oxygenation and ventilation. Objectives: To compare haemodynamic variables and ventilation parameters of I-gel and laryngeal mask airway with tracheal intubation during laparoscopic surgery. Methods: This is a prospective randomized comparative study among 90 cases of American Society of Anesthesiologists physical status class I and II, undergoing laparoscopic cholecystectomy, who were equally divided into three groups of 30 patients each: I-gel group, Laryngeal mask airway group and Tracheal tube group. Randomization was done with pick up of cards from sealed envelope. Basal readings of heart rate, systolic, diastolic and mean arterial pressure were recorded and these parameters were measured again before airway device placement, one, three and five minutes after airway manipulation, during carboperitoneum creation and before and after extubation. Oxygen saturation, end tidal CO2, airway pressure and inhaled and exhaled tidal volume and minute volume were monitored before, during and after carboperitoneum creation. Leak volume was calculated by deducing exhaled tidal volume from inhaled tidal volume. Statistical analysis (Analysis of variance test) was done to see the differences among the groups. Results: Haemodynamic perturbations were maximum with tracheal intubation and moderate with laryngeal mask airway while stable haemodynamics was observed with I-gel. Intra and inter-group comparison revealed significant differences after use of airway devices and after removal as well. Regarding ventilatory response, oxygenation and ventilation was well maintained with maximum airway pressure of mean ± SD: 20.11 ±3.46, 20.24 ±4.42, 19.05±4.82 cmH2O during carboperitoneum creation in I-gel, laryngeal mask airway and tracheal tube group respectively and oxygen saturation of 98 to 100% and end tidal CO2 level of 31-35 mmHg. In all groups, minute volume was well maintained and leak volume of 18.88±12.40, 17.13±13.32 and 20.89±12.20 ml were recorded in I-gel, laryngeal mask airway and tracheal tube group respectively during carboperitoneum creation. There was no statistically significant difference among the groups at any time regarding the monitored parameters. Conclusion: Among the three airway management devices used during general anaesthesia with positive pressure ventilation, I-gel produced least haemodynamic stress response, both supraglottic devices can be used with proper size and placement with acceptable haemodynamics and ventilation during laparoscopic surgery. DOI: http://dx.doi.org/10.3126/jkmc.v1i2.8143 Journal of Kathmandu Medical College, Vol. 1, No. 2, Oct.-Dec., 2012: 84-90

I-gel for Positive Pressure Ventilation

I-gel is a relatively new supra-glotitc airway device which is claimed to be superior to laryngeal mask airway. It can be used ingeneral anesthesia with spontaneous ventilation as well as with positive pressure ventilation.This study was designed to assess whether I-gel creates adequate laryngeal seal during positive pressure ventilation in patients undergoing laparoscopic surgery. A prospective randomized study was made among the 60 patients who underwent laparoscopic cholecystectomy under general anesthesia. Airway was managed with either I-gel insertion or endotracheal intubation and positive pressure ventilation in 30 patients each. Airway pressure, end-tidal CO2and oxygen saturation were monitored and compared between two groups. Inhaled and exhaled tidal volume, minute volume were recorded and leak volume and leak fraction was calculated and compared between two groups. Oxygenation and ventilation (oxygen saturation and end-tidal carbon dioxide pressure) was within normal limit in both groups and comparable. Leak volume in tracheal tube group was 25.33±12.41 ml and in I-gel group it was 26.43±13.19 ml. Leak fraction was 0.0487±0.023 and 0.0417±0.022 in tracheal group and I-gel group respectively. The airway pressure during C02 pneumoperitoneumwas 20.55±3.25 cm H20 in tracheal tube group and 20.21± 3.97 cm H20 in I-gel group and there was no significant leak in either group. Statistically, there was no significant difference in leak volume, leak fraction and airway pressure between the two groups. I- gel may be an alternate to tracheal tube during general anesthesia with positive pressure ventilation in patients with normal airway pressure with acceptable leak, adequate oxygenation and ventilation.

Efficacy of "jet endotracheal tube" designed by Wei for tracheal intubation

Objective To investigate the efficacy of jet endotracheal (JET) designed by Wei (WEI JET) for tracheal intubation.Methods One hundred and two ASA Ⅰ-Ⅲ and Cormack & Lehane grade Ⅰ-Ⅳ patients of both sexes,aged 15-50 yr,weighing 40-99 kg,requiring tracheal intubation under general anesthesia,were randomly allocated into 2 groups (n =51 each):conventional tracheal tube group (group C) and WEI JET group (group WJ).Groups C and WJ were further divided into 2 subgroups according to Cormack & Lehane grade:difficult airway subgroup (n =16) and non-difficult airway subgroup (n =35).The patients were tracheal intubated with the common Kendall endotracheal tube in group C.Jet ventilation (driving pressure 100 kPa,frequency of ventilation 15 bpm,I∶ E =1∶2) was performed and the patients were simultaneously tracheal intubated with WEI JET of the same internal diameter in group WJ.PETCO2 was recorded immediately after mechanical ventilation.The success rate of tracheal intubation at first attempt and time spent were recorded.The complications were also recorded within 24 h after extubation.Results Compared with group C,the intubation time was significantly prolonged,and the success rate of tracheal intubation at first attempt was increased in patients with a difficult airway than that in the patients without difficult airways in group WJ (P ＜ 0.01).There was no significant difference in PETCO2 recorded immediately after mechanical ventilation,intubation time and the success rate of tracheal intubation at first attempt between the patients with a difficult airway and the ones without difficult airways in group WJ (P ＞ 0.05).PET CO2 recorded immediately after mechanical ventilation was significantly higher and the success rate of tracheal intubation at first attempt was lower in the patients with a difficult airway than in the patients without difficult airways in group C (P ＜ 0.01).No severe barotrauma such as pneumothorax,mediastinal emphysema and subcutaneous emphysema occurred in group WJ.There was no significant difference in the incidences of laryngospasm,sore throat,and flatulence between the two groups (P ＞ 0.05).Conclusion WEI JET can not only provide adequate ventilation safely and effectively in patients requiring tracheal intubation under general anesthesia,but also increase the probability of successful tracheal intubation in patients with a difficult airway. Key words: Intubation, intratracheal; Respiration, artificial

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Introduction: The PneuX Pneumonia Prevention system comprises a flexible silicone tracheal tube (TT) with a non-stick inner lumen parylene coating, a sealing cuff and a continuous cuff pressure control device. Secretions collected inside the TT may cause blockage and serve as a medium for microbial growth that may stay protected from the patient’s immune system and antibiotic penetration. The purpose of this study was to collect initial data in order to examine and compare the amount of secretions on the inner lumen of the PneuX TT and conventional polyvinyl chloride (PVC) TT in the critically ill. Hypothesis: The PneuX TT will have a lower mass of secretion in the lumen of the TT than the PVC tubes. Methods: The study took part in two critical care units (39 tubes). Tracheal tube evaluation was both qualitative (pictures/visual impression) and quantitative (weight difference). Following extubation, tracheal tubes were immediately photographed and weighed (dirty weight). The tracheal tubes were then cleaned and reweighed (clean weight), and the weight of the secretions inside the TT lumen was then calculated (dirty weight - clean weight). Results: The mean mass of TT secretions for the PneuX TT group was 0.21g (SD=0.39; range 0-1.2) and for the PVC TT group 1.02g (SD=0.48; range 0.2-2.2); P<0.001. Photographed TTs were visually more contaminated in the PVC group. Conclusions: There was a significant increase in the accumulation of material in the inner lumen of the PVC TT group compared with the PneuX TT group. There was also a qualitative difference in the contamination of tubes with PVC TT group being visually more contaminated than the PneuX TT group. This could have negative impact in patient care such as increasing the risk of tube obstruction and the perpetuation of infection. Subsequent studies to confirm these findings, to quantify the microbiological load within the TTs and to determine the effect on outcome in terms of ventilator-associated complications are warranted.

Clinical analysis of laryngeal mask airway anesthesia and endotracheal intubation anesthesia

Objective To study the safety and efficacy of laryngeal mask airway(LMA) used in breast cancer general anesthesia. Methods Forty ASA Ⅰ or Ⅱ patients with breast cancer scheduled for selective radical mastectomy under general anesthesia were allocated randomly to either laryngeal mask airway group(group A,n =20) or tracheal tube group(group B, n = 20). SBP, DBP, HR, SpO2 of patients before anesthesia(To)/after intubation immediately (T1) and 5 minutes(T2) after intubation tracheal tube or laryngeal mask intubation/after extubation immediately (T3) and 5 minutes(T4) of after extubation tracheal tube or laryngeal mask were recorded. The different incidence of anesthetic complications and side effect were observed in both groups because intubation and extubation. Results In group B, SBP, DBP and HR were significantly higher than those in group A at T1 and T3 (P ＜ 0.05). Agitation, bucking and pharyngodynia incidence rate in group B were significantly higher than group A(P ＜ 0.05). Conclusion Ventilation with LMA in patients underwent breast cancer radical correction was better than endotracheal intubation general anesthesia in keeping stable hemodynamics and producing less anesthetic complications. Key words: Laryngeal mask airway; General anesthesia; Breast cancer radical correction

Risk of pulmonary aspiration with laryngeal mask airway and tracheal tube during positive pressure ventilation

It was with great interest that I read Bernardini and Natalini’s [1] study comparing the risk of aspiration during positive pressure ventilation via laryngeal mask airways (LMAs) and tracheal tubes. The authors rightly pointed out that fortunately this is an infrequent event and as such would require an enormous number of patients to be entered into a randomised controlled trial for meaningful conclusions to be drawn. They reported their institute’s observational data over a 10.5-year period, and concluded that their study increased the level of current evidence and that the risk of pulmonary aspiration in selected patients did not increase when a LMA was used instead of a tracheal tube. Observational studies are, however, liable to selection bias. Although rightly declared by the authors, I feel that this may not have been adequately accounted for. They chose to use propensity scores to adjust for the likelihood of patients to have received a tracheal tube over a LMA and then adding this score as a covariate to calculate an adjusted odds ratio. They highlighted this selection bias by stating that the odds ratio for aspiration in patients in whom the LMA was used was increased when the propensity score was considered in the multivariate analysis. This would imply large differences between the patients in the groups that had been assigned to have a tracheal tube or LMA. In such circumstances D’Agostino [2] recommends using the propensity score for case matching or stratification of the groups. A review of the methodology reveals particularly stringent contra-indications for LMA use at their institute, in particular, a fasting period of > 12 h required in unplanned surgery. At all of the institutes that I have worked in to date, a period of 6 h was deemed adequate for LMA use in planned and unplanned surgery as long as there were no other contra-indications. Adherence to this length of fasting may have placed more patients in the tracheal tube group undergoing unplanned surgery. As unplanned surgery was shown be associated with increased risk of pulmonary aspiration, the reason why there were so few incidences of pulmonary aspiration in the LMA group may have been because there were proportionately fewer patients in this group who underwent unplanned surgery. There was mention of the use of a default ventilator setting of 8–10 ml.kg−1actual body weight in the subjects requiring ventilation with respiratory rate adjustment based on PEco2 (or Paco2 if available). Was there any information regarding airway pressure levels or the use of neuromuscular blocking drugs in the LMA group? Both adequate neuromuscular blockade and the limiting of peak airway pressure to 20 cmH2O are recommended in the instructions for LMA use in patients undergoing positive pressure ventilation [3]. I would also be interested to know whether any information was available as to when aspiration events occurred, i.e. were they at induction, intra-operatively or postoperatively? The finding of pulmonary aspiration in seven cases of positive pressure ventilation with use of a tracheal tube as the airway device is somewhat concerning, particularly as it is widely regarded as the gold standard for airway protection, although it is reassuring that the authors of the study found no cases of mortality attributable to aspiration alone. Careful patient assessment and case selection are the mainstays of safe anaesthesia and have been previously advocated in conjunction with the use of LMA in the patient undergoing positive pressure ventilation [4]. This has been further reinforced by the findings of Bernardini and Natalini.

Effects of patient's tolerance to laryngeal mask airway and tracheal tube on the appropriate level of sevoflurane anesthesia

Objective To compare the effects of patient's tolerance to laryngeal mask airway (LMA) and tracheal tube (TT) on the appropriate level of sevoflurane anesthesia.Methods Eighty ASA Ⅰ or Ⅱ patients aged 30-60 yr weighing 50-70 kg undergoing elective thyroid or breast surgery were randomly divided into 2 groups (n=40 each):LMA group and TT group.Anesthesia wag induced with propofol 1.6mg/kg,fentanyl 3μg/kg and recuronium 0.6mg/kg.LMA or tracheal tube was inserted,and the patients were mechanically ventilated.Anesthesia was maintained with inhalation of 1.5%-3.0% sevoflurane and 50% N2O in O2 in group LMA,and with 2.5%-5.0% sevoflurane and 50% N2O in O2 in group TT.The flow of O2 and N2O was 0.7-1.0L/min,and the concentration of sevofluranee was adjusted to maintain AAI at 15-25.ECG,HR,MAP,SpO2,PETCO2,AEP and end-tidal sevoflurane concentration were continuonsly monitored.The end-tidal sevoflurane concentration was recorded at 1,5 and 10 min after LMA/TT was placed (T1-3),at 1h after skin incision (T4) and at the end of operation before removal of LMA or extubation (T5).The recovery time of consciousness,adverse cardiovascular events and adverse reactions were recorded.Results The end-tidal sevoflurane concentration was significantly lower,the recovery time of consciousness and removal of LMA or extubation time were shorter,and the incidence of adverse cardiovascular events and adverse reactions was lower in LMA group than in TT group.Conclusion At the same depth of anesthesia (AAI 15-25),sevoflurane concentration is significantly lower in LMA group than in TT group,with fewer complications and smaller cardiovascular reaction. Key words: Laryngeal masks; Intubation,intratracheal; Sevoflurane

Epinephrine administration via a laryngeal mask airway: what is the optimal dose?

Background. The aim of this animal study was to clarify the effects of laryngeal mask airway (LMA)-administrated epinephrine and to assess the optimal dose. Methods. Thirty pigs were anesthetized and intubated with a cuffed tracheal tube (TT) and an LMA. Then they were assigned to one of five groups. The control group received distilled water 10 mL via the TT; the TT group received epinephrine 50 �g/ kg via the TT; and the other three groups received two, four or six times the TT dose of epinephrine via the LMA. Heart rate (HR) and arterial pressure were monitored before and after drug administration for 15 minutes. Results. After epinephrine administration, the LMA-6 and TT groups had elevated systolic, diastolic and mean arterial pressures at 1 min and there was no significant difference between the two groups. In the TT group, these parameters peaked at 2 min then declined rapidly. In the LMA-6 group, they increased more slowly, and then maintained a plateau. The control, LMA-2 and LMA-4 groups failed to display significant persistent (>2 min) hemodynamic changes. Conclusions. We could not identify an optimal LMA-administrated epinephrine dose. The TT route is suitable when a high peak drug effect is required and the LMA route may be preferable if a persistent plateau effect is desired. Effective LMA administration of drugs may require larger doses than those given via TT.