A Simple Computational Theory of General Collective Intelligence.

Researchers have recently demonstrated that group performance across tasks tends to be correlated, motivating the use of a single metric for the general collective intelligence of groups akin to general intelligence metrics for individuals. High general collective intelligence is achieved when a group performs well across a wide variety of tasks. A number of factors have been shown to be predictive of general collective intelligence, but there is sparse formal theory explaining the presence of correlations across tasks, betraying a fundamental gap in our understanding of what general collective intelligence is measuring. Here, we formally argue that general collective intelligence arises from groups achieving commitment to group goals, accurate shared beliefs, and coordinated actions. We then argue for the existence of generic mechanisms that help groups achieve these cognitive alignment conditions. The presence or absence of such mechanisms can potentially explain observed correlations in group performance across tasks. Under our view, general collective intelligence can be conceived as measuring group performance on classes of tasks that have particular combinations of cognitive alignment requirements.

The EasyTube during general anesthesia for minor surgery: A randomized, controlled trial.

BACKGROUND: The EasyTube (EzT) is a supraglottic airway device that is used for emergency airway situations. Ventilation during general anesthesia should also be feasible, but literature on the EzT is scarce. We evaluated the EzT in comparison with the endotracheal tube (ETT) in its use during general anesthesia in a comparative study. METHODS: A total of 400 patients with American Society of Anesthesiologists (ASA) physical status I to II scheduled for minor surgery in 4 centers were randomized for ventilation via the ETT or EzT. RESULTS: In all patients, the EzT and the ETT could be inserted within 3 attempts. In all EzT patients, the inspiratory and expiratory minute volumes (6.64 ±â€Š0.71 and 6.34 ±â€Š0.69 L/min) were sufficient to reach target oxygenation values, similar to ETT patients (P  =  .59). Mean peak pressure, mean plateau pressure, and mean dynamic compliance did not differ between the groups. Sore throat and blood on the cuff after removal were the most frequent complications in both groups. CONCLUSION: Ventilation for up to 1 hour during general anesthesia in patients with ASA physical status I to II with the EzT is feasible and safe.

Repeated combined endovascular therapy with milrinone and nimodipine for the treatment of severe vasospasm: preliminary results.

BACKGROUND: Delayed vasospasm (VSP) following aneurysmal subarachnoid hemorrhage (aSAH) remains a major source of morbidity. Milrinone was recently suggested as an invasive VSP treatment option. It is a phosphodiesterase III inhibitor with vasodilating and additional positive inotrope and anti-inflammatory effects. METHODS: In this preliminary series, we included patients with severe VSP and unsuccessful maximum conservative therapy. Inclusion criteria were (1) transcranial Doppler (TCD) mean >180 cm/s; (2) increase of >50 % of TCD mean values within 6 h to values >150 cm/s; and/or (3) neurological deterioration (after exclusion of hemorrhage, hydrocephalus, and other systemic reasons). Patients received endovascular therapy with nimodipine 2 mg followed by milrinone 4-8 mg. Reinterventions were indicated aggressively in cases of persistent neurological deficits or persistent high mean TCD >180 cm/s. RESULTS: Of 121 consecutive aSAH patients, 16 (13.2 %) received endovascular VSP therapy. Of these, 11 patients (68.5 %) received ≥ 3 interventions (median 4; maximum 9); 14 (87.5 %) showed postinterventional angiographic improvement of vessel diameters; and 11 (68.5 %) showed improvement of their neurological deficits after a mean follow-up time of 4.5 months. No cardiovascular adverse events attributed to milrinone were observed. CONCLUSIONS: Milrinone may be a useful supplementary substance for endovascular VSP therapy. Aggressive reintervention indications did not cause additional adverse events.

Distance from the glottis to the grille: the LMA Unique, Air-Q and CobraPLA as intubation conduits: a randomised trial.

BACKGROUND: Supraglottic airway devices are often used in airway management to facilitate tracheal intubation. Knowledge of the distance from the grille of the device to the patient's vocal cords is essential for the safe passage of the tracheal tube below the vocal cords. OBJECTIVES: To assess the distance from the glottis to the grille of three supraglottic airway devices [LMA (LMA Unique), Air-Q (Air-Q Intubating Laryngeal Airway Reusable) and CobraPLA (Cobra Perilaryngeal Airway)] and their safe usage as intubation conduits. DESIGN: Randomised controlled trial. SETTING: Tertiary, university hospital. PATIENTS: Thirty women undergoing elective gynaecological surgery with planned supraglottic airway management. INTERVENTIONS: In-vivo fibreoptic assessment and in-vitro measurement. MAIN OUTCOME MEASURES: The distance from the grille to the glottis was defined as primary outcome. The distance from the beginning of the cuff of a tracheal tube passed through the device to the grille was assessed as secondary outcome. RESULTS: The three devices exhibited significant differences in the mean ±â€ŠSD distance from the glottis to the grille (LMA 4.6 ±â€Š1.5  cm, Air-Q 5.7 ±â€Š1.4  cm, CobraPLA 3.4 ±â€Š1.4  cm; P = 0.009). The Air-Q was predicted to allow the safe passage of a tracheal tube into the trachea, whereas the cuff was predicted to rest on the vocal cords in 57% of the LMA patients and 14% of the CobraPLA patients. CONCLUSION: Using the LMA Unique as a conduit for tracheal intubation may pose a safety risk, whereas the use of the Air-Q would position the tracheal tube at a safe depth in the trachea.

Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial.

OBJECTIVE: To determine which bedside method of detecting inadvertent endobronchial intubation in adults has the highest sensitivity and specificity. DESIGN: Prospective randomised blinded study. SETTING: Department of anaesthesia in tertiary academic hospital. PARTICIPANTS: 160 consecutive patients (American Society of Anesthesiologists category I or II) aged 19-75 scheduled for elective gynaecological or urological surgery. INTERVENTIONS: Patients were randomly assigned to eight study groups. In four groups, an endotracheal tube was fibreoptically positioned 2.5-4.0 cm above the carina, whereas in the other four groups the tube was positioned in the right mainstem bronchus. The four groups differed in the bedside test used to verify the position of the endotracheal tube. To determine whether the tube was properly positioned in the trachea, in each patient first year residents and experienced anaesthetists were randomly assigned to independently perform bilateral auscultation of the chest (auscultation); observation and palpation of symmetrical chest movements (observation); estimation of the position of the tube by the insertion depth (tube depth); or a combination of all three (all three). MAIN OUTCOME MEASURES: Correct and incorrect judgments of endotracheal tube position. RESULTS: 160 patients underwent 320 observations by experienced and inexperienced anaesthetists. First year residents missed endobronchial intubation by auscultation in 55% of cases and performed significantly worse than experienced anaesthetists with this bedside test (odds ratio 10.0, 95% confidence interval 1.4 to 434). With a sensitivity of 88% (95% confidence interval 75% to 100%) and 100%, respectively, tube depth and the three tests combined were significantly more sensitive for detecting endobronchial intubation than auscultation (65%, 49% to 81%) or observation(43%, 25% to 60%) (P<0.001). The four tested methods had the same specificity for ruling out endobronchial intubation (that is, confirming correct tracheal intubation). The average correct tube insertion depth was 21 cm in women and 23 cm in men. By inserting the tube to these distances, however, the distal tip of the tube was less than 2.5 cm away from the carina (the recommended safety distance, to prevent inadvertent endobronchial intubation with changes in the position of the head in intubated patients) in 20% (24/118) of women and 18% (7/42) of men. Therefore optimal tube insertion depth was considered to be 20 cm in women and 22 cm in men. CONCLUSION: Less experienced clinicians should rely more on tube insertion depth than on auscultation to detect inadvertent endobronchial intubation. But even experienced physicians will benefit from inserting tubes to 20-21 cm in women and 22-23 cm in men, especially when high ambient noise precludes accurate auscultation (such as in emergency situations or helicopter transport). The highest sensitivity and specificity for ruling out endobronchial intubation, however, is achieved by combining tube depth, auscultation of the lungs, and observation of symmetrical chest movements. TRIAL REGISTRATION: NCT01232166.

Comparison of the EasyTube and endotracheal tube during general anesthesia in fasted adult patients.

STUDY OBJECTIVE: To evaluate the effectiveness, safety, ease of placement, and ventilatory parameters of a new alternate airway device, the EasyTube (EzT; Teleflex Ruesch, Research Triangle Park, NC), in comparison to the endotracheal tube (ETT). DESIGN: Prospective, randomized controlled trial. SETTING: University Hospital. SUBJECTS: 200 adult ASA physical status I and II patients scheduled for surgery. INTERVENTIONS: Patients were randomized to two groups, one to receive ventilation via the EzT (n = 100) or the ETT (n = 100). After preoxygenation and induction with fentanyl and propofol, patients received muscle relaxation. The respective airway device was then inserted and mechanical ventilation was instituted. MEASUREMENTS: Ease of insertion, number of insertion maneuvers, time until airtight seal of the airway was achieved, duration of surgery, leak pressure as well as arterial oxygen saturation (SpO(2)), and end-tidal carbon dioxide (ETCO(2)) data, were recorded. MAIN RESULTS: Mallampati airway class was higher in the EzT group (P < 0.029), while thyromental distance showed no difference between the two groups. Ease of insertion was noted in the EzT group (P < 0.043). Number of insertions was equal in both groups; insertion time was shorter with the EzT (15.5 +/- 3.6 sec vs. 19.3 +/- 4.6 sec; P < 0.0001). Leak pressure and SpO(2) were not significantly different, while ETCO(2) was lower with the ETT (P < 0.024). Adjustments had to be made for two EzT group patients. No difference in frequency of laryngo-pharyngeal discomfort was observed in either group. CONCLUSION: Insertion of an EzT appears to reduce time and facilitate placement of an airway device when compared with direct laryngoscopy and tracheal intubation.

Comparison of mucosal pressures induced by cuffs of different airway devices.

BACKGROUND: High pressures exerted by balloons and cuffs of conventional endotracheal tubes, the Combitube (Tyco Healthcare Nellcor Mallinckrodt, Pleasanton, CA), the EasyTube (Teleflex Ruesch, Kernen, Germany), the Laryngeal Mask Airway (LMA North America, San Diego, CA), the Intubating Laryngeal Mask Airway (Fastrach; LMA North America), the ProSeal (LMA North America), and the Laryngeal Tube (LT; VBM Medizintechnik, Sulz, Germany) may traumatize the pharyngeal mucosa. The aim of this study was to compare pressures exerted on the pharyngeal, tracheal, and esophageal mucosa by different devices designed for securing the patient's airways. METHODS: Nineteen fresh cadavers were included. To measure mucosal pressures, microchip sensors were fixed on the anterior, lateral, and posterior surfaces of the proximal balloon and the distal cuff of the investigated devices. Depending on the respective airway device, the cuff volume was increased in 10-ml increments at the proximal balloon starting from 0 to a maximum of 100 ml, and in 2-ml increments at the distal cuff starting from 0 up to 12 ml. RESULTS: Tracheal mucosal pressures were significantly higher using the Combitube compared with the endotracheal tube and the EasyTube. Maximal esophageal pressures were significantly higher using the EasyTube compared with the Combitube. Using cuff volumes according to the manufacturers' guidelines, we found the highest pharyngeal pressures with the Intubating Laryngeal Mask Airway versus all other devices. At maximal volumes, the Laryngeal Mask Airway, the Intubating Laryngeal Mask Airway, and the ProSeal induced significantly higher pharyngeal pressures compared with all other devices. Using a pharyngeal cuff volume of 40 ml, the Intubating Laryngeal Mask Airway followed by the Laryngeal Mask Airway exerted significantly higher pressures compared with the other devices. CONCLUSIONS: Although some devices exhibit a somewhat higher mucosal pressure when compared with others, the authors believe that the observed differences of the cuff pressures do not suggest a clinically relevant danger, because the investigated devices, except the endotracheal tubes, are not intended for prolonged use.

The critical airway, rescue ventilation, and the combitube: Part 1.

Emergency and unexpected difficult airway management can rapidly deteriorate into a critical airway event such as "cannot ventilate, cannot intubate" (CVCI). A critical airway event (i.e., inadequate mask ventilation, failed intubation, and CVCI) can be resolved by rescue ventilation, thus avoiding potential neurological disability or death. Recommended options include use of the larygeal mask airway, the esophageal-tracheal Combitube (ETC; Tyco-Healthcare-Nellcor, Pleasanton, Calif), transtracheal jet ventilation, or a surgical airway. This article reviews proper use of the ETC in combination with the self-inflating bulb (SIB) and/or portable carbon dioxide detector to resolve critical airway situations. The combined use of these 3 devices provides on ideal integrated system for airway control and ventilation. In addition, critical airway events and rescue ventilation options; ETC design, technical aspects, training, insertion, and ventilation; determining ETC location (i.e., esophagus vs trachea); and monitoring ETC lung ventilation are reviewed. The SIB primarily assesses ETC location within the esophagus or the trachea; the carbon dioxide detector also permits monitoring lung ventilation. Use of the ETC in prehospital, emergency medicine, and anesthesia settings, including ETC advantages, contraindications, and reported complications will be reviewed in Part 2. How to safely exchange the ETC for a definitive airway also will be reviewed.

The critical airway, rescue ventilation, and the combitube: Part 2.

Emergency and unexpected difficult airway management can rapidly deteriorate into a critical airway event (e.g., inadequate mask ventilation, failed tracheal intubation, or cannot ventilate-cannot intubate). Recommended options to resolve a critical airway event include the laryngeal mask airway, the esophageal tracheal Combitube (ETC; Tyco-Healthcare-Nellcor, Pleasanton, Calif), transtracheal jet ventilation, or a surgical airway to avoid potential neurological disability or death. Part 1, which was published in the February 2004 AANA Journal, reviewed use of the ETC in combination with the self-inflating bulb and/or portable carbon dioxide detector as an effective rescue airway system. Important aspects of rescue ventilation, ETC training methods, how to use the ETC, and determining ETC location also were reviewed. Part 2 reviews ETC advantages, contraindications, and reported complications in prehospital, emergency medicine, and anesthesia settings. Safe methods to exchange the ETC for a definitive airway also are described. Major ETC advantages include the following: (1) easy to learn, (2) can be inserted rapidly, (3) effectively secures the airway, (4) provides adequate lung ventilation, (5) minimizes aspiration risks, (6) facilitates application of high ventilatory pressures, and (7) can be exchanged safely for a definitive airway without compromising airway control or protection.

Evaluation of the oesophageal-tracheal double-lumen tube (Combitube) during general anaesthesia.

OBJECTIVES: Evaluation of safety and effectiveness of the Combitube during general anaesthesia. PATIENTS AND METHODS: 250 patients undergoing general anaesthesia were enrolled in the study. The respective types and duration of surgery, ease of insertion of the Combitube, and potential complications were recorded. Maximum ventilatory pressures and leak fraction were also evaluated in this study. RESULTS: Duration of surgery varied between 20 and 410 min. More than 96% of the blind Combitube insertions were successful at the first attempt, with a mean time of less than 18 +/- 5 seconds (range 12-24 seconds). In 99% of patients the Combitube worked well, and adequate oxygenation and ventilation was possible. All patients were haemodynamically stable during the entire duration of surgery. In all patients, pulse oximetry showed an oxygen saturation of 97 +/- 2% and an end-tidal carbon dioxide of 38 +/- 6 mmHg. Leak fraction, calculated as a fraction of the inspired volume, did not increase to more than 5% up to a ventilation pressure of 40 cm H2O. Superficial laceration occurred in 18 patients (7.2%) without further sequelae. No severe injuries were observed during the study period. CONCLUSION: Ventilation via the Combitube appears to be safe and effective during general anaesthesia. Practice in elective cases is a requirement for successful use in an emergency situation.

Alternative management techniques for the difficult airway: esophageal-tracheal Combitube.

PURPOSE OF REVIEW: To summarize knowledge about the esophageal-tracheal Combitube in emergency medicine and anesthesia, with special emphasis on uncommon indications. Papers published between August 2003 and July 2004 are reviewed. RECENT FINDINGS: Tracheal intubation in the field is difficult and success rates are dependent upon training level (90-98%). Therefore, the esophageal-tracheal Combitube has been recommended for emergency ventilation after failed tracheal intubation with success rates of about 90%, even when performed by emergency medical technicians. Combitube insertion is easy to learn, but practice is necessary to retain skills. Use of this device has also been recommended for ventilatory support during routine anesthesia. Combitube ventilation is successful in over 96% of patients, with minimal trauma. Since only a small percentage of American anesthesiologists are familiar with the Combitube (<50%), using the device in anesthesia care may improve the skills required during emergency airway management. Blood gases are in the range of those obtained during endotracheal tube ventilation and aspiration prophylaxis is at least as good as that of the laryngeal mask airway. Successful uncommon uses of the device have also been recommended, for example, Combitube ventilation in craniomaxillomandibular surgery via the submental route and insertion of the device in a burns patient with minimal mouth opening and significant tracheal stenosis after long-term ventilation. SUMMARY: The esophageal-tracheal Combitube is a useful and efficient alternative airway characterized by high success rates in emergency situations. We recommend the use of a laryngoscope for insertion and strict adherence to the manufacturer's guidelines in order to maximize success and minimize potential injury.

Preoperative orthostatic dysfunction is associated with an increased incidence of postoperative nausea and vomiting.

BACKGROUND: Postoperative nausea and vomiting (PONV) occurs frequently after gynecologic surgery. Because hemodynamic condition seems to be influential, women presenting with preoperative orthostatic dysregulation may have an increased risk for PONV. The aim of the present study was to assess the relationship between preoperative orthostatic dysregulation and the incidence of PONV. METHODS: In a prospective observer-blinded clinical trial, 200 women who were scheduled for elective gynecologic surgery underwent an orthostatic test on the day before surgery. Based on the orthostatic test results, women were stratified into orthostatic dysregulation (OR; systolic blood pressure decrease > 20 mmHg on standing up) and nonorthostatic dysregulation (NOR; systolic blood pressure decrease < 20 mmHg) groups. RESULTS: Forty-nine women were stratified to the OR group and 151 to the NOR group. Frequencies of PONV and vomiting during the study period were higher in the OR group compared with the NOR group (77.6% vs. 31.1% and 55.1 vs. 18.5%, respectively; all P < 0.001). Women with hypotension in their history showed a significantly higher frequency of PONV within 24 h (P < 0.05). CONCLUSION: Women presenting with orthostatic dysregulation and arterial hypotension in their history exhibit an increased risk of PONV.

Current status of the Combitube: a review of the literature.

The Combitube (Tyco-Healthcare-Kendall-Sheridan, Mansfield, MA) is an easily inserted and highly efficacious device to be used as an alternative airway whenever conventional ventilation fails. The Combitube allows ventilation and oxygenation whether the device locates in the esophagus (very common) or the trachea (rare). In this report, we review studies that suggest the Combitube is a valuable and effective airway in the emergency and prehospital settings, in cardiopulmonary resuscitation, in elective surgery, and in critically ill patients in the intensive care unit. Also reviewed are studies that demonstrate the superiority of the Combitube over other supraglottic ventilatory devices in resuscitation with respect to success rates with insertion and ventilation. Contrary to the Laryngeal Mask Airway, the Combitube may help in patients with limited mouth opening. The Combitube may be of special benefit in patients with massive bleeding or regurgitation, and it minimizes the risk of aspiration.

The effects of systolic arterial blood pressure variations on postoperative nausea and vomiting.

UNLABELLED: In this clinical study, we tested the hypothesis that a marked systolic blood pressure decrease >35% (DeltaSBP >35%) from preanesthetic baseline during the induction and maintenance of anesthesia is associated with more postoperative nausea and vomiting (PONV). In 300 ASA physical status I and II women undergoing elective gynecological surgery with general anesthesia, the maximum DeltaSBP during the induction as well as maintenance of general anesthesia were calculated. Observers blinded to hemodynamic variables assessed the incidence of PONV. The overall incidence of nausea (visual analog scale >4) and vomiting within the immediate observation period (0-2 h) was 39% and 25%, respectively. Frequency of nausea and vomiting in the late observation period was 21% and 9%, respectively. Women with a DeltaSBP >35% during the induction of anesthesia suffered from a more frequent incidence of PONV within the immediate (57% versus 35% and 41% versus 22%, respectively; P < 0.01) and within the late observation period (33% versus 18% and 19% versus 7%, respectively; P < or = 0.01). In women with a DeltaSBP >35% during maintenance of anesthesia, a more frequent incidence of nausea within the immediate observation period (53% versus 36%; P < 0.05) was found. We conclude that a maximum DeltaSBP >35% during the anesthetic induction is associated with an increased incidence of PONV after gynecological surgery during general anesthesia. IMPLICATIONS: A prospective clinical investigation revealed that a marked systolic blood pressure decrease >35% (DeltaSBP >35%) during the induction of general anesthesia is associated with an increased incidence of postoperative nausea and vomiting (PONV). The association between a DeltaSBP >35% during maintenance of general anesthesia and PONV is less pronounced.