Pharyngeal oxygen delivery device sustains manikin lung oxygenation longer than high-flow nasal cannula

Purpose

Hypoxemia during a failed airway scenario is life threatening. A dual-lumen pharyngeal oxygen delivery device (PODD) was developed to fit inside a traditional oropharyngeal airway for undisrupted supraglottic oxygenation and gas analysis during laryngoscopy and intubation. We hypothesized that the PODD would provide oxygen as effectively as high-flow nasal cannula (HFNC) while using lower oxygen flow rates.

Methods

We compared oxygen delivery of the PODD to HFNC in a preoxygenated, apneic manikin lung that approximated an adult functional residual capacity. Four arms were studied: HFNC at 20 and 60 liters per minute (LPM) oxygen, PODD at 10 LPM oxygen, and a control arm with no oxygen flow after initial preoxygenation. Five randomized 20-minute trials were performed for each arm (20 trials total). Descriptive statistics and analysis of variance were used with statistical significance of P < 0.05.

Results

Mean oxygen concentrations were statistically different and decreased from 97% as follows: 41 ± 0% for the control, 90 ± 1% for HFNC at 20 LPM, 88 ± 2% for HFNC at 60 LPM, and 97 ± 1% (no change) for the PODD at 10 LPM.

Conclusion

Oxygen delivery with the PODD maintained oxygen concentration longer than HFNC in this manikin model at lower flow rates than HFNC.

Pharyngeal airway dimensions in Iranian female young adults with different skeletal patterns using cone-beam computed tomography

OBJECTIVES

To assess the oropharyngeal airway in Iranian female young adults with different skeletal patterns using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This descriptive, cross-sectional study evaluated 105 CBCT scans of female patients between 18 and 35 years retrieved from the archives of a radiology clinic. The images were evaluated in axial, sagittal, and frontal sections. In the axial plane, the maximum and minimum cross-sectional area (CSA) of the airways at the oropharynx, minimum width (anteroposteriorly), and minimum depth (laterally) were measured using Mimics Medical software. The oropharyngeal volume was measured by NemoFAB software. The values were compared among the groups with different sagittal, vertical, and transverse patterns. The correlation of indices with airway measurements was analyzed using Monte Carlo Chi-square and Pearson's correlation coefficient.

RESULTS

No significant difference was noted in oropharyngeal airway dimensions and volume among cases with different skeletal sagittal, vertical, and transverse patterns (P > 0.05) except for class III patients with normal transverse pattern in whom maximum CSA in low-angle group was larger than that in normal-angle group (P < 0.05) and class I normal-angle patients in whom maximum CSA in transverse normal group was smaller than that in constriction group (P < 0.05).

CONCLUSIONS

Oropharyngeal dimensions were not significantly different in Iranian female young adults with different skeletal patterns.

An oropharyngeal device for airway management of conscious and semiconscious patients: A randomized clinical trial

OBJECTIVE

No oropharyngeal devices exist for use in conscious and semiconscious trauma patients during emergency evacuation, transport, or resuscitation. We aimed to test the hypotheses that the ManMaxAirway (MMA) is better tolerated than the standard Guedel-style device in awake volunteers and that it produces a jaw thrust and improves air flow.

METHODS

This was a randomized cross-over study of healthy volunteers with either the MMA or standard device. The primary outcome of tolerability was defined as maintaining the device in place for 60 seconds. Secondary outcomes included respiratory system function and jaw thrust. Resistance to airflow through the device lumen was measured in situ and when placed in subjects in the pulmonary laboratory alone. Jaw thrust was quantified as displacement between the mandibular condyle and condylar fossa apex relative to baseline visualized with magnetic resonance imaging (MRI).

RESULTS

We enrolled 19 subjects. Of these, a convenience sample of 5 individuals was selected for MRI; the remaining individuals (n = 14) were randomized for the cross-over study. All 14 subjects were able to maintain the MMA for 60 seconds compared with 2/14 (14%) with the standard device (odds ratio, 145; 95% confidence interval, 6.3-3314). Subjects reported that the experimental device was more comfortable and its placement did not trigger the gag reflex. Airway resistance produced by the MMA in an oscillatory flow model was nearly an order of magnitude lower than that of the standard device (experimental vs standard, 8 Hz-0.092 vs 0.786 cmH20·s/L; 15 Hz-0.193 vs 1.321 cmH20·s/L). Rapid induction of the gag reflex precluded further measurements with the standard device. Forced oscillation pulmonary testing in conscious volunteers with and without the MMA demonstrated that the device decreased respiratory system resistance to airflow and reduced respiratory elastance (31% ± 8% and 44% ± 13.4%, respectively; P < 0.05). MRIs of the subjects (n = 5) with the MMA in place showed a significant jaw thrust compared with baseline (7 ± 1 mm).

CONCLUSIONS

The MMA proved well tolerated in conscious subjects, resulting in an opening of the anatomic airway and a decreased resistance to airflow.

The evaluation of the relationship between cervical vertebral anomalies with skeletal malocclusion types and upper airway dimensions

Objectives: To compare the prevalence of cervical vertebral anomalies (CVAs) in different skeletal malocclusions and to evaluate the relationship between upper airway dimension and vertebral anomalies. Methods: A retrospective study was performed on lateral cephalometric radiographs of 2062 patients aged 7-49 years. Skeletal malocclusion type, presence of CVAs, and upper airway area of 1856 patients who met the inclusion criteria of the study were recorded. The obtained data were transferred to the SPSS program for statistical analysis. Results: The mean age of the patients was 13.8 ± 3.7 years. The prevalence of CVAs was 45.7%. There was no significant difference in prevalence between skeletal malocclusions (p = 0.89). According to airway measurements, no significant difference was found between patients with and without CVAs (p = 0.718). Conclusion: The present results suggest that there is no direct effect of skeletal malocclusion type and upper airway dimension in the etiology of CVAs.

Evaluations of the tongue and hyoid bone positions and pharyngeal airway dimensions after maxillary protraction treatment

OBJECTIVE

To assess changes in the tongue and hyoid bone positions and airway dimensions after maxillary protraction using lateral cephalograms.

METHODS

Lateral cephalograms were obtained before (C0) and after (C1) an observation period for untreated children with skeletal Class I malocclusion and before (T0), immediately after (T1), and one year after (T2) maxillary protraction in children with skeletal Class III malocclusion. Cephalometric measurements were compared between the time points in both patient groups.

RESULTS

Immediately after maxillary protraction, the tongue moved superiorly and the nasopharyngeal and superior oropharyngeal airway dimensions increased. No significant changes in the middle or inferior oropharyngeal airway dimensions or in the hyoid bone position were noted after treatment.

CONCLUSIONS

Maxillary protraction improved tongue posture and modified the nasopharyngeal and superior oropharyngeal airway dimensions in patients with skeletal Class III malocclusion. Consequently, maxillary protraction may restore the intra- and extraoral balance and improve respiratory function.

Efficiency and Efficacy of Two Techniques of Preoxygenation during Modified Rapid Sequence Intubation

Background:

Apneic mass movement of oxygen by applying continuous positive airway pressure (CPAP) is possible only when the airway is kept patent which helps to reduce the rate of desaturation.

Aims:

The aim of this study was to check the efficiency of preoxygenation and apneic oxygenation by assessing the drop in partial pressure of arterial oxygen (PaO₂) during apnea with and without keeping an oropharyngeal airway to maintain the patency of airway.

Settings and Design:

This prospective observational study was conducted at a tertiary care center.

Materials and Methods:

Sixty patients undergoing robotic and laparoscopic-assisted surgeries requiring modified rapid sequence intubation were recruited for the study. In Group A, CPAP was not applied during preoxygenation and oropharyngeal airway was not used, but oxygen was administered at 5 L/min during the apnea. In Group B, CPAP of 5 cmH₂O was maintained during preoxygenation and after induction an oropharyngeal airway was inserted. Patients in both the groups were induced and paralyzed following standardized anesthesia protocol.

Statistical Analysis Used:

Chi-square test, independent t-test, and ANCOVA were used as applicable.

Results:

Group B showed significantly higher mean PaO₂ levels after preoxygenation (525.3 ± 42.5 vs. 500.8 ± 51) and at 90 s of apnea (494.8 ± 42.6 vs. 368.6 ± 98.4) as compared to Group A. The fall in PaO₂ was significantly lower in Group B. The rise in partial pressure of arterial carbon dioxide was comparable in both groups.

Conclusion:

Preoxygenation with CPAP of 5 cmH₂O followed by apneic oxygenation with CPAP keeping the airway patent with an oropharyngeal airway results in significantly higher PaO₂ after preoxygenation and slower reduction in PaO₂ during apnea.

Cone Beam Computed Tomography Analysis of Oropharyngeal Airway in Preadolescent Nonsyndromic Bilateral and Unilateral Cleft Lip and Palate Patients

OBJECTIVE

The objective of this study was to assess the volume, area, and dimensions of the oropharyngeal airway (OPA) in a previously repaired nonsyndromic unilateral cleft lip and palate (UCLP) versus bilateral cleft lip and palate (BCLP) patients when compared with noncleft controls using cone beam computed tomography (CBCT).

DESIGN

This was a retrospective case-control study.

SETTING

The Cleft Care Center and outpatient clinic that are affiliated to our faculty were the settings for the study.

PARTICIPANTS

A total of 58 CBCT scans were selected of preadolescent individuals: 14 BCLP, 20 UCLP, and 24 age- and gender-matched noncleft controls.

VARIABLES

Variables were volume, cross-sectional area (CSA), midsagittal area (MSA), and dimensions of OPA.

STATISTICAL ANALYSIS

One-way analysis of variance and post hoc tests were used to compare variables. Statistical significance was set at P ≤ .05.

RESULTS

UCLP showed significantly smaller superior oropharyngeal airway volume than both controls and BCLP ( P ≤ .05). BCLP showed significantly larger CSA at soft palate plane and significantly larger MSA than both UCLP and controls ( P < .05).

CONCLUSIONS

UCLP patients at the studied age and stage of previously repaired clefts have significantly less superior oropharyngeal airway volume than both controls and BCLP patients. This confirms that preadolescents with UCLP are at greater risk for superior oropharyngeal airway obstruction when compared with those BCLP and controls. Furthermore, BCLP patients showed significantly larger CSA at soft palate plane and MSA than both controls and UCLP patients. These variations in OPA characteristics of cleft patients can influence function in terms of respiration and vocalization.

Comparison of supraglottic airway laryngopharyngeal tube, oropharyngeal and nasopharyngeal airway use by Polish soldiers on the manikin with difficult airway

Airway obstruction represents 6% of avoidable deaths in a combat zone. Statistical analysis of deaths in the battlefield during combat missions in Iraq and Afghanistan shows that 1% of the soldiers are killed because of airway obstruction. The aim of the study was to objectively evaluate the use of S.A.L.T. (Supraglottic Airway Laryngopharyngeal Tube), oropharyngeal airway (OPA) and nasopharyngeal airway (NPA) on the manikin with difficult airway to assess the risk of air introduction into the stomach during ventilation trauma patient and time of insertion of each device.

MATERIAL AND METHODS

A prospective study was conducted with the participation of 34 soldiers of the Polish Armed Forces (PAF). They ventilated a manikin using testing devices, to assess the volume of air entering the lungs and the stomach we used specially constructed flowmeters. The mean and median values of all measurements were calculated and compared by means of the Student's t test.

RESULTS

102 device placements and 204 ventilations were performed and evaluated during the study. The median time required for placement of S.A.L.T. was 12.44 sec vs 13.32 sec for NPA vs 9,34 sec for OPA (p<0.05). Mean volumes of air entering the lungs and stomach during ventilation with S.A.L.T. were (ml) 194.23 and 166 respectively, for NPA 218.13 vs 200.93 and for OPA 197.47 vs 169.22.

CONCLUSIONS

Total volume of air entering into the stomach using S.A.L.T. was the lowest among all three devices. The use of NPA did not show any clinically important advantage, the fastest insertion time for OPA may be of value in the battlefield.

Assessment of the Risk Factors for Oro-Dental Injuries to Occur during General Anesthesia and Measures taken by Anesthesiologist to Prevent them

BACKGROUND AND AIM

Anesthesiologist gain access to the airway passage orally with the help of laryngoscope. Dental trauma can occur during different steps in anesthesia. The aim of the study is to evaluate the risk factor for dental trauma perioperatively and to look for the preventive measures mostly employed by the anesthesiologist to prevent dental insult.

MATERIALS AND METHODS

The present study involved 40 anesthetists working in private hospitals using simple random sampling. They were asked to answer a questionnaire designed to look for the risk factors that makes tooth most prone for injury and find out the measures that anesthesiologists follow to prevent such injuries to occur. Codes were placed for the obtained data and Medcalc statistical package was used for analysis.

RESULTS

Injuries mostly occur during intubation with a laryngoscope in patients where there is limited visibility to the hypopharynx. Maxillary left central incisor was mostly affected. Some anesthetists used plastic blades or curved blades to prevent such injury.

CONCLUSION

Patient with poor dentition and history of difficult intubation should be sent for pre-operative dental evaluation to prevent dental injuries.

Approaches to manual ventilation

Manual ventilation is a basic skill that involves airway assessment, maneuvers to open the airway, and application of simple and complex airway support devices and effective positive-pressure ventilation using a bag and mask. An important part of manual ventilation is recognizing its success and when it is difficult or impossible and a higher level of support is necessary to sustain life. Careful airway assessment will help clinicians identify what and when the next step needs to be taken. Often simple airway maneuvers such as the head tilt/chin lift and jaw thrust can achieve a patent airway. Appropriate use of airway adjuncts can further aid the clinician in situations in which airway maneuvers may not be sufficient. Bag-mask ventilation (BMV) plays a vital role in effective manual ventilation, improving both oxygenation and ventilation as well as buying time while preparations are made for endotracheal intubation. There are, however, situations in which BMV may be difficult or impossible. Anticipation and early recognition of these situations allows clinicians to quickly make adjustments to the method of BMV or to employ a more advanced intervention to avoid delays in establishing adequate oxygenation and ventilation.

Long-term evaluation of swallowing function before and after sagittal split ramus osteotomy

The aim of this study was to determine whether mandibular setback by sagittal split ramus osteotomy (SSRO) influences swallowing function. The subjects were 14 patients with skeletal class III malocclusions who underwent setback surgery by SSRO. Morphological changes were studied on cephalograms, and swallowing function was evaluated by videofluorography before the operation (T0) and at 7-10 days (T1), 3 months (T2), and 6 months (T3) after surgery. The angle between nasion, sella, and hyoid bone (HSN) and the sella-hyoid distance had increased significantly at T1. The hyoid bone returned to the preoperative position at T2. There were no significant changes in the oropharyngeal space at any time. On videofluorographic assessment, lingual movement, soft palate movement, and epiglottic movement had decreased at T1, but all patients recovered at T2. The oral transit time was significantly longer at T1 than at T0. Our results confirm that SSRO influences swallowing function. Swallowing function appears to stabilize by 3 months after surgery.

Successful long-term airway stabilization with a modified pacifier in a syndromic infant

Airway management is one of the key aspects of neonatal anesthesia, and an oropharyngeal airway is used in daily intensive care practice to relieve upper-airway obstruction. Cleft palate is among the various congenital malformations that can cause difficult airway management. We describe a syndromic infant with alobar holoprosencephaly, whose long-term airway patency was maintained with a modified infant pacifier. We would like to share our experience and contribute to the literature with the introduction of a readily available and easily-inserted apparatus.