Correction to: Protective ventilation with high versus low positive end-expiratory pressure during one-lung ventilation for thoracic surgery (PROTHOR): study protocol for a randomized controlled trial.

After publication of the original article [1], the authors have notified us that two of the collaborator first and last names have been inverted in the "PROTHOR Investigators" table.

Protective ventilation with high versus low positive end-expiratory pressure during one-lung ventilation for thoracic surgery (PROTHOR): study protocol for a randomized controlled trial.

BACKGROUND: Postoperative pulmonary complications (PPC) may result in longer duration of in-hospital stay and even mortality. Both thoracic surgery and intraoperative mechanical ventilation settings add considerably to the risk of PPC. It is unclear if one-lung ventilation (OLV) for thoracic surgery with a strategy of intraoperative high positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM) reduces PPC, compared to low PEEP without RM. METHODS: PROTHOR is an international, multicenter, randomized, controlled, assessor-blinded, two-arm trial initiated by investigators of the PROtective VEntilation NETwork. In total, 2378 patients will be randomly assigned to one of two different intraoperative mechanical ventilation strategies. Investigators screen patients aged 18 years or older, scheduled for open thoracic or video-assisted thoracoscopic surgery under general anesthesia requiring OLV, with a maximal body mass index of 35 kg/m2, and a planned duration of surgery of more than 60 min. Further, the expected duration of OLV shall be longer than two-lung ventilation, and lung separation is planned with a double lumen tube. Patients will be randomly assigned to PEEP of 10 cmH2O with lung RM, or PEEP of 5 cmH2O without RM. During two-lung ventilation tidal volume is set at 7 mL/kg predicted body weight and, during OLV, it will be decreased to 5 mL/kg. The occurrence of PPC will be recorded as a collapsed composite of single adverse pulmonary events and represents the primary endpoint. DISCUSSION: PROTHOR is the first randomized controlled trial in patients undergoing thoracic surgery with OLV that is adequately powered to compare the effects of intraoperative high PEEP with RM versus low PEEP without RM on PPC. The results of the PROTHOR trial will support anesthesiologists in their decision to set intraoperative PEEP during protective ventilation for OLV in thoracic surgery. TRIAL REGISTRATION: The trial was registered in clinicaltrials.gov ( NCT02963025 ) on 15 November 2016.

Quality of life and pre-operative anxiety level in patients scheduled to undergo thoracic surgery.

PURPOSE: Increased preoperative anxiety levels may lead to adverse outcomes. We aimed at assessing the relationship between quality of life (QoL) and preoperative anxiety level during the 4-week preoperative period in patients scheduled to undergo thoracic surgery and we tried to identify patients who could benefit from preoperative supportive measures. METHODS: One hundred patients comprised the study population (52 men and 48 women) out of the initial 136, who were scheduled to undergo thoracic surgery. Mean age was 56±15 years (±SD). After obtaining informed consent, participants were asked to answer a questionnaire, through a personal interview, 12 to 15 h prior to their scheduled thoracic operation. The questionnaire included questions on demographics and incorporated the State Anxiety Inventory (STAI) and SF-36 scales. RESULTS: Female patients (p=0.023), unemployed patients (p=0.01) and patients that were scheduled for a mediastinoscopy (p=0.001) experienced increased anxiety level. Lower scores in several parameters related to the QoL were found to be associated with increased anxiety level. Limitations in patients' ability to work or to perform other everyday activities as a result of mental health problems (p=0.006), low vitality (p<0.001), bad general mood (p<0.001), deteriorated general health (p<0.001) and general mental health (p<0.001) were associated with preoperative anxiety. No differences were found in anxiety level among lung cancer and non-lung cancer patients. CONCLUSION: This study showed an inverse proportional correlation between preoperative QoL and anxiety during the 4-week period prior to thoracic surgery. Appropriate pharmaceutical and psychological support may improve patients' anxiety level.

The intubating laryngeal mask airway Fastrach for emergence after carotid endarterectomy.

We determine the feasibility of using the intubating laryngeal mask airway Fastrach (ILM) as a ventilatory device during emergence from anesthesia after use as an airway intubator in patients undergoing carotid endarterectomy. Thirty-five patients (ASA 2-3, 53-84 yr) were studied. Induction was with midazolam/fentanyl/etomidate and maintenance was with sevoflurane 1-2% in O2 33-50% and N2O. Neuromuscular blockade was with cisatracurium. Tracheal intubation was with a flexible lightwand via the ILM. After successful intubation, the ILM remained in the pharynx, but with the cuff deflated. After surgery, but before anesthesia was discontinued, baseline cardiovascular variables were recorded. The ILM cuff was then reinflated, the tracheal tube removed, the anesthesia breathing system connected to the ILM and anesthesia discontinued. Any changes in the cardiovascular variables greater than +/- 20% baseline values were noted from cuff reinflation to 1 minute after ILM removal. Any adverse respiratory (laryngospasm, coughing, gagging, stridor, SpO2 <94%, end-tidal carbon dioxide >45 mmHg, regurgitation/aspiration) or electrocardiographic (ST segment or rhythm changes) events were also noted. Patients were questioned about postoperative sore throat at 2 and 24 hr. ILM insertion and intubation through the ILM were successful in all patients. Adequate ventilation was achieved in all patients before intubation and after extubation. The mean (range) time taken from cuff reinflation to ILM removal was 9 (5-21) min. The rate pressure product remained within +/- 20% baseline values in all patients. There were no adverse respiratory or electrocardiographic events. There were no adverse neurological events. The surgical field was satisfactory. Postoperative sore throat occurred in 14% at 2 hr and 0% at 24 hr. We conclude that the ILM can be used as a ventilatory device for emergence from anesthesia after use as an airway intubator for carotid endarterectomy.

Flexible lightwand-guided intubation using the intubating laryngeal mask airway in the supine, right, and left lateral positions in healthy patients by experienced users.

IMPLICATIONS: Flexible lightwand-guided intubation with the intubating laryngeal mask airway is equally effective in the supine, right, and left lateral positions in healthy patients by experienced users.

Use of the intubating laryngeal mask for airway management and light-guided tracheal intubation in the lateral position.

Sudden accidental loss of the airway during surgery is potentially hazardous especially when the patient is lying in any position which prevents easy intubation of the trachea. We describe two patients lying in the lateral position who required urgent airway management and endotracheal intubation. In both cases endotracheal intubation was achieved successfully using a light-guided technique--with a prototype illuminated flexible catheter--through an intubating laryngeal mask airway.

Use of an illuminated flexible catheter for light-guided tracheal intubation through the intubating laryngeal mask by nurses.

We evaluated the ability of inexperienced personnel in using a prototype illuminated flexible catheter to assist tracheal intubation through the intubating laryngeal mask in anaesthetised, paralysed patients. The device consists of a completely flexible thin plastic catheter, a bulb attached to its distal end and a 15-mm concentric adapter at its proximal end. The illuminated catheter is placed into a straight silicone tracheal tube in such a way that the bulb is placed at the distal end of the tracheal tube. Six nurses inexperienced in tracheal intubation followed a 2-hr training program by using the device through the intubating laryngeal mask in a mannequin and then intubated 10 patients each, with instruction from an anaesthetist. All patients (n=60) were ASA 1-2, scheduled to undergo general anaesthesia for elective surgery. After fentanyl/propofol induction the intubating laryngeal mask was inserted. When an adequate airway was established, patients received atracurium and the endotracheal tube preloaded with the device was inserted through the intubating laryngeal mask and by observing the glow in the neck was advanced into the trachea. The final outcome and the duration of the procedure were recorded. The intubating laryngeal mask was inserted successfully in all patients. The success rate of intubation was 57/60 (95%); 38 patients at first attempt and 19 after two or three attempts. The mean (+/-SD) duration of the procedure in the first five patients in the series of each nurse was 74+/-40 s while in the last five patients it was diminished to 52+/-23 s (P=0.01). We conclude that the described methodology has the potential for more widespread use of tracheal intubation through the intubating laryngeal mask even by inexperienced personnel.

Light-guided tracheal intubation using a prototype illuminated flexible catheter through the intubating laryngeal mask.

We evaluated the efficacy of a newly developed prototype illuminated flexible catheter to facilitate tracheal intubation through the intubating laryngeal mask and compared this light-guided technique with the conventional blind tracheal intubation through the intubating laryngeal mask. The illuminated flexible catheter consists of a completely flexible thin plastic catheter, a bulb attached to its distal end, a 15-mm concentric adapter at its proximal end connected with a battery and a power switch. The device is placed into a silicone tracheal tube in such a way that the bulb protrudes from the distal end of the tracheal tube. One hundred adult patients, ASA I-III, scheduled to undergo propofol/fentanyl/atracurium anaesthesia for elective surgery were studied. All participants underwent a randomized double comparative cross over trial with respect to the tracheal intubation technique through the intubating laryngeal mask. The light guided tracheal intubation was performed as follows; the tracheal tube preloaded with the illuminated flexible catheter was inserted through the intubating laryngeal mask and by observing the glow in the neck was advanced into the trachea. Whenever resistance was felt during insertion, appropriate adjusting manoeuvres were performed. The intubating laryngeal mask was inserted successfully in all patients. The success rate for the blind and light-guided technique was 91% and 100%, respectively (P = 0.003). The mean (+/- SD) duration including appropriate intubating laryngeal mask placement and tracheal intubation, was significantly lower in the light-guided tracheal intubation technique, than with the blind tracheal intubation (31 +/- 8 s vs. 43 +/- 18 s; P < 0.0001). We conclude that the use of an illuminated flexible catheter carries advantages either in optimizing the intubating laryngeal mask position in the laryngopharynx or in achieving a quick and safe light-guided advancement from laryngopharynx into the trachea.

Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients.

The prediction of difficult intubation in obese patients was investigated by co-estimating the degree of visibility of oropharyngeal structures in conjunction with the respective body mass index. Data were collected prospectively in a series of 1833 consecutive adult patients. Body mass index (BMI) in kg m-2 was used as a measure of obesity (morbid: > 40, moderate: 30-40, no obesity: < 30). The oropharyngeal class findings were assessed using the original methodology as well as by a modification requiring the tongue to be pulled forward by the examiner. Difficult intubation was defined as inadequate exposure of the glottis by direct laryngoscopy. Both oropharyngeal class methodologies were of equal sensitivity, whereas the modified technique presented a significantly higher positive predictive value (50.0% vs. 37.2%, P < 0.01). Statistical analysis revealed an increased risk of difficult laryngoscopy among obese patients compared with subjects with normal body mass index (20.2% vs. 7.6%, P < 0.001). When obesity is estimated with respect to oropharyngeal class the positive predictive value is greatly improved (66.7% vs. 20.2%, P < 0.001). We conclude that obesity which is associated with a disproportionately large base of the tongue, is a predisposing factor for difficult laryngoscopy.

Use of the laryngeal mask for management of the compromised airway--a case report.

A 54-year old woman was scheduled for thoracotomy for excision of a tumor of the left upper lobe. Reduced thyromental distance and thyroid enlargement were identified by the preoperative physical examination and inability to visualize the larynx was encountered during direct laryngoscopy. A 37-Fr left sided double lumen tube was inserted in trachea with great difficulty after three failed attempts. One lung anesthesia underwent uneventfully and postoperatively it was decided to exchange the double lumen tube to a single lumen tracheal tube. After the extubation, five failed attempts of reintubation were performed. A laryngeal mask airway (LMA) size 3 was passed easily achieving an airtight airway. The patient underwent an uneventful prolonged (105 min) weaning via the LMA which was left in place until the patient regained full consciousness. Peripheral oxygen saturation remained greater than 95% throughout the airway manipulation. LMA insertion is an easy non-invasive technique and should be considered whenever airway management proves difficult.

Comparison of laryngeal mask airway with endotracheal tube for airway control.

The study was designed to compare the effectiveness and ease of the insertion of the laryngeal mask airway (LMA) and the endotracheal tube (ETT) according to the presence of signs of difficult airway. Eight hundred seventy nine patients undergoing elective surgery were randomly allocated in the ETT group (n = 453) and the LMA group (n = 426). Airway assessment was performed using the original Mallampati classification and measuring the maximum range of the head and neck mobility. Anesthesia was induced with midazolam, fentanyl, propofol and succinylcholine. The severity of difficulty in ETT or LMA insertion was estimated on a three-point scale according to the final outcome of the airway management (0 = easy, 1 = difficult, 2 = impossible). Patients with suspected or observed difficulty in tracheal intubation proved to have easy insertion of LMA. Additionally, the ease of intubation was unrelated to potential failure of proper insertion of LMA. Although "difficult" patients in both studied groups have similar frequencies, the underlying anatomical characteristics were not similar.

The laryngeal mask airway: a survey of its usage in 1,096 patients.

The frequency and pattern of laryngeal mask airway (LMA) usage in a regional general hospital has been studied. Data were collected prospectively by means of a standardized record sheet which was completed at the time of anesthetic administration. During a 19-month period 10,150 patients underwent surgical procedures requiring general or regional anesthesia, of which 1,096 (men/ women: 791/305, ASA 3 or 4: 350, mean age: 64 years) were managed with the LMA. A clinically pattern airway was provided in 99.75% of occasions of whom 44.4% breathed spontaneously and 55.3% underwent positive pressure ventilation. The monthly frequencies of LMA usage increased significantly during the second year of the survey (25.1% vs 12.8%). Problems were recorded in 16.3% of cases: air leak 8.0%, laryngospasm 1.8%, desaturation (SpO2 < or = 90%) 1.8%, severe hypercarbia (PETCO2 > or = 50 mmHg) 1.0%, regurgitation 0.09%, sore throat 3.4%. No patient required intensive care management postoperatively. There were five cases of failed intubation managed with the LMA. This survey has shown that LMA has a well established role in anesthetic practice. Use of this device is equally safe and effective for both controlled and spontaneous ventilation in a wide range of starve patients undergoing most types of surgery.

Evaluating the difficult airway. An epidemiological study.

The epidemiological characteristics of 359 difficult intubations resulted from retrospectively collected data in a series of 4.742 individual anaesthetic case records of consecutive adult patients (2392 men, 2350 women) undergoing general anaesthesia for routine surgery. The preoperative assessment of each patient's airway was performed using standardized guidelines. Mandibular length, body weight and mobility of jaw, head and neck were evaluated with simple measurements. The presence of protruding maxilla or upper teeth, tongue tumor or cyst, long narrow mouth, short muscular neck and deviation of larynx or trachea was based on clinical and/or radiological examination. Severity of difficulty in intubation was estimated on a five-point scale grades (0-4) according to the view obtained at laryngoscopy and the final outcome of airway management. Difficult intubation (grades 1-4) was confirmed in 359 cases (7.6%) of which 208 were anticipated (57.2%). The effectiveness of preoperative evaluation had a positive correlation with the level of difficulty since, the greater the grade of difficulty the greater the sensitivity. The prevalence of failed intubation (grade 4) was 0.5%. Risk factors which had been correlated with the relative size of the tongue proved to have low probability and level of difficulty of intubation. The most important risk factor was limited jaw movement (median grade of difficulty: 4, positive predictive value: 75.0%). Large endemic goitre and thalassaemia constitute RFs contributing occasionally to difficult airway. The positive predictive value was 61.5% and 40.9% respectively. The combination of risk-factors had a cumulative impact contributing to the high level of difficulty.