Prospective, randomized comparison of laryngeal tube and laryngeal mask airway in pediatric patients.

BACKGROUND: While reports of the use of laryngeal mask airway (LMA)-Classic in great patient numbers are available, data on the use of the laryngeal tube (LT) in this age group is limited. The two devices are compared in a prospective randomized trial to evaluate success rates and quality of airway seal. METHODS: Sixty children, aged 2-8 years, scheduled for elective surgical interventions were randomized to be ventilated with LMA or LT. Standardized anesthesia was induced with fentanyl and propofol. Number of insertion attempts, time until first tidal volume and intraoperative tidal volumes, and peak pressures were recorded. Airway leak pressure was measured with cuff pressure adjusted to 60 cmH(2)O. RESULTS: Demographic data were comparable, average age in the LMA/LT group was 5.2 +/- 1.9/5.3 +/- 1.9 years. Insertion was successful in 29 of 30 patients in the LMA group (second attempt 8) and in all patients in the LT group (second attempt 3). Time until first tidal volume for LMA/LT was 23.1 +/- 7.3/19.2 +/- 8.6 s (P < 0.05). Peak airway pressures for LMA and LT were 15.3 +/- 3.4 and 17.1 +/- 4.0 cmH(2)O (P < 0.05) with tidal volumes of 10.2 +/- 2.2 and 10.2 +/- 1.9 ml.kg(-1), airway leak pressure was 19.2 +/- 8.6 cmH(2)O for LMA and 26.3 +/- 7.3 cmH(2)O for LT (P < 0.001). CONCLUSION: Insertion success rate is high with both LMA and LT in the age group studied. The airway leak pressure, serving as an estimate to judge quality of airway seal, is higher with the LT.

The ProSeal laryngeal mask airway and the laryngeal tube Suction for ventilation in gynaecological patients undergoing laparoscopic surgery.

BACKGROUND AND OBJECTIVE: ProSeal Laryngeal Mask Airway (PLMA) and Laryngeal Tube Suction (LTS), supraglottic airway devices allowing gastric drainage, were compared in this prospective, randomized study for airway management under conditions with elevated intra-abdominal pressure induced by capnoperitoneum. METHODS: Fifty patients undergoing elective gynaecological laparoscopic surgery were randomized to two groups of 25 each. After induction of general anaesthesia, devices were inserted, correct placement was verified, airway leak pressure was measured, and a gastric tube was inserted. Ease of insertion, quality of airway seal, risk of gastric insufflation and patient comfort were investigated. RESULTS: There were no differences in patient characteristics data for both groups. First-time insertion success rates were comparable for both groups: 92%--first attempt, 8%--second attempt for PLMA and LTS. Time until delivery of the first tidal volume for PLMA and LTS was 23.2 +/- 6.1 and 23.5 +/- 6.6s, airway leak pressure was 45.4 +/- 4.9 cmH2O and 45.6 +/- 6.7 cmH2O with cuff pressures adjusted to 60 cmH2O. No gastric insufflation, gas loss or signs of regurgitation were detected. Placement of a gastric tube was successful in all patients. Patients were questioned for sore throat and dysphagia after removal of devices. Sore throat was stated in 1%/0% (PLMA) and 8%/4% (LTS) after 6/24 h, dysphagia in 4%/4% (PLMA) and 12%/4% (LTS). CONCLUSIONS: Both devices provide a secure airway even under conditions of elevated intra-abdominal pressure. In this pilot study, no differences concerning handling or quality of airway seal were detected between PLMA and LTS.

[First clinical experiences with the new LTS. A laryngeal tube with an oesophageal drain]. / Erste klinische Erfahrungen mit dem neuen LTS. Ein Larynx-Tubus mit ösophagealer Drainagemöglichkeit.

OBJECTIVE: The feasibility of prototypes of the LTS, a laryngeal tube with an additional oesophageal drain tube for pressure relief, was tested for ventilation during surgery. METHODS: After approval of the ethics committee, a LTS was placed in 30 orthopaedic patients, ASA I and II, induction of general anaesthesia with fentanyl and propofol. Position of the LTS was verified by auscultation and end tidal CO(2)-measurement. Oxygen saturation, number of placement attempts, cuff pressure, time until first tidal volume, tidal volume and airway pressures were registered intraoperatively. Patients were questioned about hoarseness and soar throat 1 h, 6 h and 24 hours after surgery, graded on a visual analogue scale (VAS). RESULTS: 16 women and 14 men were investigated. In 29 patients (96.7%), the LTS was placed successfully (second attempt in three patients). In one patient, sufficient ventilation was not possible. In this case and in another patient with sufficient ventilation but estimated duration of surgery >3 h, endotracheal intubation was performed. Average time until first tidal volume was 17.3 seconds, ventilation was performed for 74 minutes. Pulse oximetric oxygen saturation was > or =97% at all times. Auscultation over the stomach was negative in all patients with an average cuff pressure of 73.7 cm H(2)O. During controlled ventilation aiming at an end tidal CO(2) of 35 mmHg (average 36.3 mmHg), an average tidal volume of 579 ml was reached, resulting in an inspiratory peak pressure of 20.2 cm H(2)O. Minimal traces of blood on the LTS were found in 5 patients, hoarseness was present in one patient after 6 hours, soar throat was stated after 1 hour by one patient (VAS 3), after 6 hours by 6 (average VAS 2.7) and after 24 hours by 3 patients (VAS 1.3). CONCLUSIONS: The LTS can be used for ventilation during elective surgery and can be placed with a high success rate. Postoperative complaints are infrequent and mild.

[Comparison of different laryngeal mask airways in a resuscitation model]. / Vergleich verschiedener Larynxmasken am Reanimationsmodell.

OBJECTIVE: The standard laryngeal mask airway LMA-Classic is recommended in the ILCOR guidelines as alternative to facemask and tracheal tube during cardiopulmonary resuscitation. LMA-Unique, LMA-Fastrach and LMA-ProSeal are additional variants that are compared with the standard LMA in a resuscitation model. METHODS: Tidal volumes, chest compressions and signs of gastric inflation are measured in a standardized resuscitation model (Ambu Cardiac Care Trainer with notebook and thumper). Ten 3-minute resuscitation cycles were performed with facemask and all LMAs (Classic, Unique, Fastrach, ProSeal, all size 4) with a ventilation : compression ratio of 2:15. To allow comparison with tracheal tube and to judge safety margins, another ten resuscitation cycles were performed with tracheal tube and all laryngeal masks with continuous chest compressions after two initial ventilations. The bag-valve device used for ventilation was replaced by an automatic transport ventilator in a third series with continuous chest compressions. Cuff pressures were set at 80 cm H2O. RESULTS: During interrupted chest compressions, adequate ventilation was possible with all devices. Tidal volumes for facemask, LMA-Fastrach and LMA-ProSeal were significantly (p < 0.001) higher than with LMA- Classic and LMA-Unique. During continuous chest compressions, significant differences (p < 0.001) occurred when comparing tracheal tube, Fastrach and ProSeal with the other two laryngeal mask airways, which did not reach recommended tidal volumes. During ventilation with the automatic transport ventilator, values for all devices except LMA-ProSeal dropped significantly, adequate ventilation was possible with tracheal tube, Fastrach and ProSeal. Signs of gastric inflation were found during ventilation with facemask and - to a lesser extent - with LMA-Classic. CONCLUSION: In the resuscitation model chosen, all laryngeal mask airways are possible alternatives for ventilation during cardiopulmonary resuscitation. The new LMA-ProSeal and also the LMA-Fastrach allow higher tidal volumes even during elevated intrathoracic pressures caused by continuous chest compressions, performing superior to the standard laryngeal mask airway. For inclusion of these devices in the ILCOR guidelines, further research in patients is warranted.

[Equipment of physician-staffed ambulance systems in the state of Baden-Wuerttemberg]. / Ausstattung von Notarztbesetzten Rettungsmitteln in Baden-Württemberg.

BACKGROUND: Laws regulating emergency medical systems in the federal state of Baden-Wuerttemberg call for equipment of physician-staffed ambulances that is based on current knowledge in emergency medicine. The grade of implementation is determined using single issue complexes. METHODS: A total of 127 emergency physician bases were located and each received a questionnaire regarding the equipment of the physician-staffed ambulances and helicopters and planned supplementation of the equipment, deadline was 30 June 2001. RESULTS: Of the 127 stations 116 (91.3%) participated. A 12-lead ECG is available in 52.6%, out-of-hospital fibrinolysis is possible in 15 bases (12.9%). Alternatives to endotracheal intubation are carried in 53.3% (cricothyroidotomy: 83.3%) and 31 bases provide capnometry or other devices for verifying correct tube placement. A mobile phone is available in 88 bases (75.9%). CONCLUSIONS: When comparing equipment of physician-staffed ambulances statewide, striking differences can be found.

Assessment of the use of the laryngeal tube for cardiopulmonary resuscitation in a manikin.

During 60 3-min CPR sequences, the face mask, laryngeal tube and tracheal tube were compared using an Ambu Megacode Trainer. Ten 3-min sequences each were performed for both a combination of the face mask and laryngeal tube with a bag-valve device (compression-ventilation ratio 5:1). With continuous chest compressions, ten 3-min CPR sequences each were performed for a combination of the laryngeal tube and tracheal tube with a bag-valve device and ten 3-min CPR sequences each for a combination of the laryngeal tube and tracheal tube with an automatic transport ventilator. Signs of gastric inflation occurred only with the face mask. Ventilation with the laryngeal tube was significantly better than with the face mask and comparable to the tracheal tube during ventilation with the bag-valve device and with the automatic transport ventilator. Chest compressions caused a significant decrease in tidal volumes during ventilation with the automatic transport ventilator. The findings of this study support the idea of the laryngeal tube as a new adjunct for emergency airway management, but will have to be verified during clinical practice.