Mask Ventilation Research Articles

Management of a Difficult Airway With Direct Ventilation Through Nasal Airway Without Facemask

Mask ventilation is a key component of airway management for oral surgeons and anesthesia care providers. Clinicians often encounter a difficult airway in which adequate mask ventilation may be difficult or impossible. Difficult mask ventilation has been described as the inability for an experienced anesthesiologist to provide adequate face mask ventilation because of one or more of the following problems: inadequate mask seal, excessive gas leak, or excessive resistance to the ingress or egress of gas. 1 Although the exact pathogenesis of the difficult airway is not clearly defined, the presence of upper airway obstruction has been demonstrated to be the key contributor. Risk factors for difficult mask ventilation and upper airway obstruction correlate well and include increased age, obesity, and history of snoring or sleep apnea. 2,3 Relaxation of the upper airway musculature during sleep or anesthesia also contributes to upper airway obstruction and difficult mask ventilation. 1,3,4 The loss of upper airway muscle tone combined with the gravitational pull on the tongue and soft palate have been shown to result in airway collapse. 3-6 It is therefore logical to assume that creation of a patent upper airway would improve mask ventilation. This principle has been demonstrated in a recent study comparing oro-nasal mask ventilation and nasal mask ventilation, 7 as well as in this report. Report of a Case

An Evaluation of the Rapid Airway Management Positioner in Obese Patients Undergoing Gastric Bypass or Laparoscopic Gastric Banding Surgery

A new positioning device, the Rapid Airway Management Positioner (RAMP, Airpal Inc., Center Valley, PA) was evaluated to determine if there was an improvement in either mask ventilation, direct laryngoscopy, or both with the use of the RAMP in this patient population. Fifty-one morbidly obese patients (BMI > 35kg/m(2)) undergoing elective bariatric surgery were enrolled. Ventilation and laryngoscopy was performed in the neutral and head-elevated laryngoscopy position (HELP). Direct laryngoscopy was performed noting the glottic view according to the Cormack-Lehane classification (Samsoon and Young, Anesthesiology 42:487, 1987). Mask ventilation was then recommenced. The HELP, or "ramped," position was achieved by inflating the RAMP, which was placed underneath the patient prior to entering the OR. Once proper HELP position was achieved, a second laryngoscopy was performed followed by endotracheal intubation. Two main outcomes were noted in the neutral and HELP positions: (1) laryngoscopic view and (2) ease of ventilation. The inflated ramped position provided greater ease of ventilation as compared to the neutral position (p = 0.0003). There was also a significant improvement in the glottic view in the ramped position (p = 0.04). Ease of intubation was perceived to be severely difficult among two, and overall use of the positioning device was found to be difficult among seven of the residents. The RAMP effectively positions morbidly obese patients in the HELP position. Ease of ventilation and laryngoscopic view were both improved with its use in this patient population.

Gender difference in mask ventilation training of anesthesia residents

Study Objective To investigate whether gender difference has an effect on an anesthesia resident's ability to perform successful mask ventilation. Design Cohort study. Setting Surgical operation theater of a university-affiliated hospital. Patients 839 ASA physical status I, II, and III patients undergoing general anesthesia performed by residents. Intervention Mask ventilation was performed by 21 different anesthesia residents. Measurements Difficult mask ventilation was defined as the inability of an unassisted resident to maintain oxygen saturation, significant gas flow leakage beneath the face mask, need to increase gas flow, no perceptible chest movement, assistance required using a two-handed mask ventilation technique, or use of the oxygen flush valve more than twice. Main Results Instances of difficult mask ventilation were observed in 210 patients (25.0%), though all were adequately ventilated with a face mask. Difficult mask ventilation was observed significantly more often with female (29.8%) than male (20.0%) residents. Residents' gender was shown to be an independent risk factor for difficult mask ventilation. Conclusions Gender difference has an effect on the mask ventilation learning process, as it was more difficult for female residents to provide a tight air seal in the early stage of training.

Prediction and Outcomes of Impossible Mask Ventilation

There are no existing data regarding risk factors for impossible mask ventilation and limited data regarding its incidence. The authors sought to determine the incidence, predictors, and outcomes associated with impossible mask ventilation. The authors performed an observational study over a 4-yr period. For each adult patient undergoing a general anesthetic, preoperative patient characteristics, detailed airway physical exam, and airway outcome data were collected. The primary outcome was impossible mask ventilation defined as the inability to exchange air during bag-mask ventilation attempts, despite multiple providers, airway adjuvants, or neuromuscular blockade. Secondary outcomes included the final, definitive airway management technique and direct laryngoscopy view. The incidence of impossible mask ventilation was calculated. Independent (P < 0.05) predictors of impossible mask ventilation were identified by performing a logistic regression full model fit. Over a 4-yr period from 2004 to 2008, 53,041 attempts at mask ventilation were recorded. A total of 77 cases of impossible mask ventilation (0.15%) were observed. Neck radiation changes, male sex, sleep apnea, Mallampati III or IV, and presence of beard were identified as independent predictors. The receiver-operating-characteristic area under the curve for this model was 0.80 +/- 0.03. Nineteen impossible mask ventilation patients (25%) also demonstrated difficult intubation, with 15 being intubated successfully. Twelve patients required an alternative intubation technique, including two surgical airways and two patients who were awakened and underwent successful fiberoptic intubation. Impossible mask ventilation is an infrequent airway event that is associated with difficult intubation. Neck radiation changes represent the most significant clinical predictor of impossible mask ventilation in the patient dataset.

Airway Obstruction During Mask Ventilation of Very Low Birth Weight Infants During Neonatal Resuscitation

The delivery of adequate but not excessive ventilation remains one of the most common problems encountered during neonatal resuscitation, especially in the very low birth weight infant. Our observations suggest that airway obstruction is a common occurrence after delivery of such infants, and we use colorimetric carbon dioxide detectors during bag-and-mask resuscitation to assist in determining whether the airway was patent. We reviewed our experience to determine the frequency of the occurrence of recognizable airway obstruction during resuscitation of very low birth weight infants. The previous prospective trial randomly assigned preterm infants <32 weeks' gestation to resuscitation with either room air or 100% oxygen using pulse oximetry. Colorimetric carbon dioxide detectors were used to assist with bag-and-mask ventilation and to confirm intubation. From the video recordings, the number of positive pressure breaths without a color change in the detector until the breaths were associated with an unequivocal color change was counted as obstructed breaths. From the analog tracings, the number of breaths that had a peak pressure plateau of >/=0.2 second and were not associated with a color change was recorded as the number of obstructed breaths. None of the studied infants required cardiopulmonary resuscitation or received epinephrine, and all were judged to have an effective circulation during resuscitation. Six of the 24 infants enrolled in the trial received only continuous positive airway pressure. The remaining 18 infants received a median of 14 obstructed breaths (range: 4-37 breaths) delivered over a mean and median interval of 56.7 and 45.0 seconds, respectively (range: 10.0-220.0 seconds). A subgroup of 11 infants was analyzed using airway-pressure data. The target peak inspiratory pressure was 30 cm H(2)O. Ten of these 11 infants had obstructed breaths as defined by no change in the PediCap despite reaching the target pressure for >/=0.2 second. Airway obstruction occurs in the majority of the very low birth weight infants who receive ventilation with a face mask during resuscitation and the use of a colorimetric detector can facilitate its recognition and management.

Mask ventilation in the early management of congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS) is a rare disorder of breathing which is due to abnormal autonomic control; it is characterised by alveolar hypoventilation that is most marked during non...

Ultrasound Guidance for Axillary Plexus Block Does Not Prevent Intravascular Injection

DIRECT visualization of anatomy by ultrasound during regional anesthesia was considered to likely minimize the incidence of complications of regional anesthesia due to needle misplacement. Neural impalements have been reported under direct vision of the brachial plexus. We report a case of inadvertent vascular puncture leading to a seizure during an ultrasound-guided axillary block.A 27-yr-old man, American Society of Anesthesiologists physical status IE, was admitted for a penetrating trauma on the volar aspect of his right hand. Brachial plexus block was accepted by the patient and was performed under ultrasound guidance, associated with nerve stimulation as currently done at our institution. Standard monitoring was installed, and the patient received oxygen (3 l/min) via nasal prongs. A high-quality transverse sonogram of the axilla was obtained (Aloka Prosound 4000 S with a 12-MHz probe; Aloka Holding Europe AG, Zug, Switzerland), and all major structures, i.e. , the four nerves, the axillary artery, and two veins, were clearly identified. A resident performed the block under direct control of an experienced anesthesiologist (P.J.Z.). The needle was introduced using the in-plane approach. The median nerve was approached first, and a typical motor response was obtained by nerve stimulation. After two negative aspiration test results, two boluses of 4 ml mepivacaine, 2%, were slowly injected, and a “doughnut sign” was obtained after the needle was displaced from the anterior (4 ml) to the posterior (4 ml) aspect of the nerve. The radial nerve was then approached according to the same procedure (typical motor response during nerve stimulation, two boluses of 4 ml of the same solution slowly injected after negative aspiration test results). The needle was then redirected toward the ulnar nerve, which was located in the right upper quadrant.1The ulnar nerve was also easily located, and the injection was begun according to the same procedure. At that moment, approximately 4 min after the first injection, the patient became agitated and unresponsive, and perioral myoclonias were observed. The injection was immediately stopped, and the needle was withdrawn. No sign of abnormal bleeding was observed in the axilla. Mask ventilation was difficult because a generalized seizure occurred. Approximately 2 min after the seizure had started, tracheal intubation was performed after administration of 350 mg thiopental and 100 mg suxamethonium. Seizures stopped immediately, and oxygen saturation was 100% as soon as a signal could be obtained. On the electrocardioscope screen, sinus rhythm and rare premature ventricular beats were noted. After a 10-min observational period, because the patient was stable under general anesthesia maintained with sevoflurane in oxygen, it was decided to proceed with the surgical procedure. Opioids were not needed during the 1-h surgical procedure, suggesting that the block was efficient. This was confirmed in the recovery room because motor and sensory blocks were complete and totally resolved 3 h after injection. The patient fully recovered without any sequelae and was discharged uneventfully on the following day. No blood sampling was performed.Intravascular injection of local anesthetics remains a major risk of regional anesthesia and peripheral nerve blocks.2A repeated aspiration test is recommended but may not rule out an intravascular injection with certainty.3Administration of an epinephrine-containing test dose is not often performed during peripheral nerve blocks because of either simplicity or reluctance to use epinephrine. Ultrasound guidance, which allows the anesthesiologist to see the tip of the needle during the whole procedure, is thought to prevent intravascular injection. In this case, however, intravascular injection was likely. The time interval between injection and seizure was short and probably incompatible with local absorption of the drug. Importantly, intravascular injection was not detected by direct visualization, and we did not suspect vessel puncture at any time before the complication occurred. The two first injections had distorted the anatomy of the axilla, and the veins were probably displaced or compressed by the local anesthetic, making their visualization more difficult.In conclusion, ultrasound guidance for nerve block, even in experienced hands and with a clear sonogram of the needle and anatomical structures, does not eliminate the risk of intravascular injection. Standard safety rules should not be minimized because of ultrasound guidance.

Incidence and Predictors of Difficult and Impossible Mask Ventilation

Incidence and Predictors of Difficult and Impossible Mask Ventilation

Bag and Mask Ventilation

To the Editor: In his review of skin and softtissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA), Daum (July 26 issue)1 cites a study2 indicating that intravenous trimethoprim–sulfamethoxazole (TMP-SMX) is significantly less effective than vancomycin for the treatment of serious S. aureus infections. However, in this randomized, double-blind, comparative trial of TMP-SMX and vancomycin, therapeutic failures occurred only in patients with methicillin-susceptible S. aureus (MSSA) infections. TMP-SMX was successful in treating all MRSA infections, including tricuspid-valve endocarditis. Clinical failures commonly occurred with MSSA tricuspid-valve endocarditis; otherwise, the cure rates with TMPSMX and with vancomycin were similar. On the basis of the results of this study, vancomycin may be superior for MSSA infections; however, the same cannot be concluded for MRSA infections. Although the currently available clinical data for community-associated MRSA skin infections are sparse, in this era of an increasing incidence of MRSA infection and concern about the variable efficacy of vancomycin, TMP-SMX may be a useful alternative in selected cases.

Difficult Airway Management Following Supratentorial Craniotomy: A Useful Maneuver with a New Device

To the Editor: The McGrath® Video Laryngoscope (Aircraft Medical, Edinburgh, Scotland) is a video-based system for tracheal intubation that utilizes a video camera embedded into a “camera stick” (Fig. 1). The device can be disarticulated, which was critical in the urgent airway management of the following case:Figure 1.: The McGrath® Videolaryngoscope.A 31-year-old 62 kg ASA PS 2E female patient presented for urgent ventriculoperitoneal shunt because of hydroceplalus. She had undergone a left temporoparietal craniotomy 4 days prior for removal of an encephalocele. On examination, the patient was noted to have new limitation of her mouth opening (2.5 cm) because of incisional pain in the left temporal region. Review of the previous anesthetic record revealed no difficulty with intubation using the GlideScope® Model GVL 115 (Verathon Medical, Bothell, WA) electively for teaching purposes in this patient with a previously unremarkable airway examination. After induction and easy ventilation via a mask, succinylcholine 120 mg was administered IV. However, her mouth opening did not improve and one attempt at direct laryngoscopy with a MacIntosh 3 blade and one additional attempt using the GlideScope® were made. Neither device could be introduced into the mouth using standard technique with the patient’s head in “sniffing position.” Mask ventilation was easily maintained between attempts at laryngoscopy. The McGrath® laryngoscope blade and camera stick were disarticulated from its handle and easily inserted midline; similar to the insertion of a tongue depressor. The handle was re-attached revealing a Cormack/Lehane Grade 1 view of the glottis. The trachea was intubated without difficulty on the first attempt. Kawaguchi et al. described the phenomenon of pseudoankylosis of the mandible after supratentorial craniotomy as “persistent limitation of mouth opening due to extra-articular pathology including infection, irradiation, burns, or surgical incision of the masticatory muscles” (1). He noted a significantly decreased maximum mouth opening in adult patients after frontotemporal craniotomy compared with those after occipital or limited frontal craniotomy occurring in as little as 3 days after surgery. Our patient had undergone left temporal craniotomy 4 days before reoperation. The technique of disarticulating a standard laryngoscope is rarely practiced but is reportedly effective when large breasts impede conventional placement of the blade (2). The ease of reattachment of the McGrath® Video Laryngoscope handle is due to unique end to side connection. The side of the handle connects to the end of the McGrath® blade. This feature allows the laryngoscopist to reconnect the handle and blade and so eliminating the obstacle posed by the patient’s chest, large breasts, or limited mouth opening. The inability to use the GlideScope® for this patient’s reoperation was because of its design. The GlideScope® is designed as a rigid, fused unit of medical grade plastic (3). The Glidescope® blade has a pronounced 60° angulation, a maximum width of 26 mm and a maximum thickness of 14.5 mm. The fused design of the Glidescope® did not allow the tip of the blade to pivot into the hypopharynx in this patient with limited mouth opening. An additional virtue of video-laryngoscopy is that the position of the camera extends the laryngoscopist’s field of view from 10° with conventional laryngoscopy using line of sight to 60° utilizing video technology (4). The disarticulating design of the McGrath® Video laryngoscope allowed the trachea of a patient with limited mouth opening to be intubated easily. Irene P. Osborn, MD Division of Neuroanesthesia Mount Sinai School of Medicine New York, NY [email protected] Elizabeth Cordes Behringer, MD Department of Anesthesiology University of California, Irvine Orange, CA David C. Kramer, MD Division of Neuroanesthesia Mount Sinai School of Medicine New York, NY

Predicting Difficult and Impossible Mask Ventilation

The cannot intubate–cannot ventilate scenario is among the most feared situations confronting airway managers. Kheterpal et al.1 deserve congratulations for attempting to elucidate some of its intricacies.To accomplish that, 61,252 adult patients undergoing anesthesia at their institution were enrolled in the study. Of this number, 22,660 cases underwent attempts at mask ventilation. Data were derived from all cases in which mask ventilation had been attempted. The Discussion explains and table 6 enumerates that 586 patients underwent elective awake intubation. Patients undergoing elective awake intubation do not receive attempts at mask ventilation and therefore were excluded from the most important aspects of data collection and calculations.Awake intubation is performed for patients who are anticipated to have difficult or impossible mask ventilation and/or difficult or impossible laryngoscopy. These 586 patients were the most likely to have been difficult or impossible mask ventilations and/or difficult or impossible laryngoscopies. This is born out by the data. Comparing the awake fiberoptic intubation group with the standard induction group demonstrated a higher incidence of one or more risk factors in the awake group. There is no way of knowing the frequency of grade 3 or grade 4 mask ventilation, or the frequency of difficult or impossible intubation in these 586 patients. I expect the frequency to have been relatively high.Having excluded the high-risk population from the data, only low-risk patients were analyzed. Consequently, their results and conclusions are not applicable to high-risk patients or even the general population of patients. Their conclusions are applicable to low-risk groups.Furthermore, it is curious that beards, Mallampati-Samsoon class III and IV, and age older than 57 yr are identified as predictors of grade 3 mask ventilation (difficult mask ventilation) but are not named as predictors of grade 4 mask ventilation (impossible mask ventilation). Snoring is the only shared risk factor between grade 3 and 4 mask ventilation. Thyromental distance less than 6 cm was identified as a risk factor for grade 4 mask ventilation, but not grade 3. I would have anticipated more overlap between the two grades. It is noteworthy that Mallampati-Samsoon class III and IV is identified as a predictor of grade 3 mask ventilation but not as a predictor of grade 3 mask ventilation and difficult intubation.

Be Aware of the Patient with an Eye Patch

To the Editor: A 78-yr-old woman was scheduled for right upper lobectomy under general anesthesia. She weighed 54 kg and was 5 feet 10 in. tall. Her medical history was significant for hypertension, a 50-yr history of cigarette smoking, and an enucleation of the right eye for an unknown tumor 10 years previously. She had a glass eye but preferred to wear a large black (pirate) eye patch that covered the entire orbit including the eyebrows. Her physical examination was unremarkable with a class 2 airway. After induction of anesthesia with fentanyl and thiopental, vecuronium was given for muscle relaxation. Mask ventilation with sevoflurane in 100% oxygen proved difficult as a large leak was detected around her face. A new larger and well-inflated face mask was placed on her face but a large leak was still detected. A second anesthesiologist assisted by holding the mask with both hands, but the leak was still present. Only by increasing the fresh gas flow to 12 L were the lungs ventilated adequately despite the leak. A repeat pressure leak test of the anesthetic machine was done but no abnormality was seen. The cause of the problem was discovered when the eye patch was removed. The orbital cavity had no glass eye and an anatomical passage from the mouth cavity to the orbit of the eye was clearly seen. The problem was easily solved by packing the orbit with a 4 in. moist vaginal pack. Be aware of the patient with an eye patch. Should it be difficult to ventilate via mask due to a large orbital leak a moist vaginal pack can be used.

Respiratory Depression and Difficult Ventilation After Inadvertent Epidural Administration of Remifentanil

To the Editor: An otherwise healthy 60-year-old man weighing 61 kg was scheduled for elective cholecystectomy under epidural anesthesia. A T8–T9 epidural catheter was placed and 5 mL of a local anesthetic mixture was given via the catheter. The local anesthetic mixture (30 mL) was intended to contain 50 mg tetracaine (lyophilized powder), 1% lidocaine, and epinephrine 1:200,000. However, 1 mg remifentanil was mistakenly substituted for 50 mg tetracaine in the mixture. Two additional 6-mL doses of the mixture were given epidurally at 5-min interval. The patient reported slight light-headedness after the first dose. His hemoglobin oxygen saturation (SPo2) decreased to 36% and the patient became unconscious while developing rigidity of the chest and abdominal muscles after the third dose. Mask ventilation was initiated, but was difficult, and the SPo2 increased to 76%. The patient received IV propofol 100 mg and vecuronium 8 mg and the SPo2 increased to 100% with mask ventilation. The trachea was intubated and surgery was performed under general anesthesia. There were no neurological sequelae after the surgery. Our patient received 567 μg remifentanil epidurally via three injections over 10 min. The recommended IV bolus dose of remifentanil during general anesthesia is 1 μg/kg. (1) Although 167 μg remifentanil given in the first dose to this patient was much larger than the recommended IV dose of 61 μg, muscle rigidity, respiratory depression, and change of consciousness did not occur. The absence of these signs may have been due to a delay caused by diffusion of remifentanil from the epidural space into the systemic circulation, and its rapid metabolism by nonspecific esterases (1,2). The remifentanil formulation contains 15 mg glycine per 1 mg remifentanil powder and our patient received 8.5 mg glycine epidurally. Intrathecal administration of glycine in dogs caused hindlimb twitching, pain, and convulsions (1). Intrathecal infusion of glycine alone or as part of the remifentanil formulation resulted in dose-dependent, but reversible, motor impairment in rats (3). The ED50 for this effect was 6.5 μg glycine/min over 90 min (3). The lack of neurological deficits in our patient may have been due to the different routes (epidural versus intrathecal) of injection. Xuebing Xu, MD Shouzhang She, MD Departments of Anesthesiology the First People's Hospital of Guangzhou Guangzhou, China Shanglong Yao, MD Departments of Anesthesiology Union Hospital of Tongji Medical College Wuhan, China Martin Mok, MD Departments of Anesthesiology Taipei Medical University Taipei, Taiwan Zhiyi Zuo, MD, PhD Departments of Anesthesiology University of Virginia Charlottesville, VA [email protected]

Incidence and Predictors of Difficult and Impossible Mask Ventilation

Incidence and Predictors of Difficult and Impossible Mask Ventilation

Incidence and Predictors of Difficult and Impossible Mask Ventilation

Mask ventilation is an essential element of airway management that has rarely been studied as the primary outcome. The authors sought to determine the incidence and predictors of difficult and impossible mask ventilation. A four-point scale to grade difficulty in performing mask ventilation (MV) is used at the authors' institution. They used a prospective, observational study to identify cases of grade 3 MV (inadequate, unstable, or requiring two providers), grade 4 MV (impossible to ventilate), and difficult intubation. Univariate and multivariate analyses of a variety of patient history and physical examination characteristics were used to establish risk factors for grade 3 and 4 MV. During a 24-month period, 22,660 attempts at MV were recorded. 313 cases (1.4%) of grade 3 MV, 37 cases (0.16%) of grade 4 MV, and 84 cases (0.37%) of grade 3 or 4 MV and difficult intubation were observed. Body mass index of 30 kg/m or greater, a beard, Mallampati classification III or IV, age of 57 yr or older, severely limited jaw protrusion, and snoring were identified as independent predictors for grade 3 MV. Snoring and thyromental distance of less than 6 cm were independent predictors for grade 4 MV. Limited or severely limited mandibular protrusion, abnormal neck anatomy, sleep apnea, snoring, and body mass index of 30 kg/m or greater were independent predictors of grade 3 or 4 MV and difficult intubation. The authors observed the incidence of grade 3 MV to be 1.4%, similar to studies with the same definition of difficult MV. Presence of a beard is the only easily modifiable independent risk factor for difficult MV. The mandibular protrusion test may be an essential element of the airway examination.

Disposable Colorimetric Carbon Dioxide Detector Use as an Indicator of a Patent Airway During Noninvasive Mask Ventilation

Colorimetric carbon dioxide detectors are useful indicators of proper endotracheal tube placement. We have found that they also are helpful during bag and mask ventilation as an indicator of a patent airway. In this report, we describe our experience with these devices for use during preintubation airway stabilization as observed during videotaped performances from a prospective, randomized trial of intubation premedication.

Non-invasive Respiratory Support in Blunt Chest Injury

Objective. To optimize the results of treatment in patients with acute respiratory failure (ARF) due to lung contusion, by using the methods of non-invasive mask respiratory support. Materials and methods. The study covered 31 patients with severe blunt chest injury, multiple costal fractures, and hypoxemic ARF. The patients underwent assisted ventilation (AV) in the CPAP+PSV mode through a facial or nasal mask. Physiological parameters were recorded during non-invasive mask ventilation (NIMV) in the stepwise fashion. A control group comprised 25 patients with the similar severity of injury and ARF who were given conventional AV. Results. In 67.7% of the study group patients, NIMV was effective in improving oxygenation and external respiration, without exerting negative hemodynamic effects. Endotracheal intubation and AV could be avoided in these patients. Comparison of the study and control groups revealed a significant reduction in the incidence of secondary pneumonias in the NIMV group and in the duration of treatment. Mask ventilation could decrease mortality from 44% in the control group to 9.7% in the NIMV group. Conclusion. NIMV applied to patients with hypoxemic ARF in the presence of lung contusion improves pulmonary function and, in the bulk of patients, allows endotracheal intubation and AV and consequently their associated complications. When mask ventilation is employed, management of patients becomes shorter and simpler and mortality rates substantially decrease.

An Audible Indication of Exhalation Increases Delivered Tidal Volume During Bag Valve Mask Ventilation of a Patient Simulator

Self-inflating manual resuscitators (SIMRs) can mislead caregivers because the bag, unlike a Mapleson-type device, reinflates even without patient exhalation. We added a whistle as an audible indicator to the exhalation port of a SIMR. In randomized order, each participant provided two sets of breaths via mask ventilation with a SIMR, one with and one without audible feedback, to a Human Patient Simulator modified to log lung volume changes. The last three breaths in each set were used to compare average tidal volume (Vt) under both conditions. Eighty-seven advanced cardiac life support trainees (54 males, 33 females) with clinical experience averaging 6.4 +/- 9.4 yr were recruited. Average Vt delivered with the standard SIMR was 486 +/- 166 mL and 624 +/- 96 mL with the modified SIMR. Average Vt delivered by a modified SIMR was significantly larger by 40% when it followed standard SIMR use and 19% when using the modified SIMR first. Use of a SIMR with an audible indicator of exhalation significantly (P < 0.001) increased mask ventilation of a patient simulator, suggesting that mask ventilation of a patient with a SIMR may also be increased by objective, real-time feedback of exhaled Vt.

Airway management of patient with Smith–Lemli–Opitz syndrome for gastric surgery: case report

A case of term, 5-day-old boy, with low birth weight of 2.4 kg, with Smith-Lemli-Opitz syndrome (SLOS) who was first scheduled for gastrostomy tube placement and later for pylorotomy, is discussed. General appearance of face and small chin showed possible difficulties during intubation, which are well known from the literature. Anesthetic plan included possibility of fiberoptic intubation. Mask induction and ventilation had been successful but attempts to intubate patient using fiberoptic bronchoscope had not been feasible and both procedures had been performed using laryngeal mask airway (LMA#1) with spontaneous ventilation without complications. In this case, we are showing the ability to secure the airway in a small infant with SLOS using LMA and the possibility to perform successfully surgery on the gastrointestinal tract.

A Comparison of the Laryngeal Tube and Bag-Valve Mask Ventilation by Emergency Medical Technicians: A Feasibility Study in Anesthetized Patients

Airway management is of major importance in emergency care. The basic technique for all health care providers is bag-valve mask (BVM) ventilation, which requires skill and may be difficult to perform. Endotracheal intubation, which is the advanced method for securing the airway, is a demanding technique that has been shown to be associated with infrequent success, even when used by experienced paramedical personnel. Therefore, alternative airway devices have been sought. The use of the laryngeal tube (LT) by experienced anesthesia personnel had been studied in anesthetized patients and manikins in emergency medical training. We decided to evaluate the ability of inexperienced firefighter-emergency medical technician students (fire-EMT) to insert the LT or perform BVM in anesthetized patients. Thirty fire-EMTs randomly inserted the LT (n = 15) and performed 1 min of ventilation or used the BVM (n = 15). We found that all students successfully (100%) inserted the LT. Those who inserted the LT on the first attempt (73%) required 48.2 +/- 14.7 s for the insertion. Both the LT and BVM provided adequate oxygenation and ventilation. In this study, we found that inexperienced fire-EMT students inserted LT and performed 1-min ventilation with a reasonable success rate and insertion time in anesthetized patients.