A comparative evaluation of the sniffing, the simple head extension and the head hyperextension positions for laryngoscopic view and intubation difficulty in adults undergoing direct laryngoscopy.

OBJECTIVE: This work aimed to compare between the laryngoscopy positions; sniffing, simple head extension and head hyperextension positions to assess whether the laryngeal view, intubation time and intubation difficulty could improve with one of these positions than the others. DESIGN: Prospective randomized three arms clinical trial. SETTING: Operation room, the phoniatrics unit [removed for blind peer review]. PARTICIPANTS: The study included 75 cases with 25 cases in each group. Group "A" with head in the sniffing position, Group "B" with the head in simple extension position, Group "C" with head in hyperextension position. RESULTS: The three groups were compared regarding intubation time and laryngoscopic view time. Intubation time showed statistically significant difference between the three groups. Mean of sniffing group (No. = 25) was 13.19 s (± 3.35). Mean of simple extension group (No. = 25) was 11.29 s (± 3.14). Mean of Hyperextension group (No. = 25) was 14.39 s (± 4.14). Laryngoscopic view time showed statistically highly significant difference between the three groups. Mean of sniffing group (No. = 25) was 17.19 s (± 7.27). Mean of simple group (No. = 25) was 12.18 s (± 4.46). Mean of hyperextension group (No. = 25) was 17.08 s (± 6.51). CONCLUSION: Comparing the sniffing, the simple extension and the hyperextension positions, the simple extension position showed the best time regarding intubation time and laryngoscopic view time.

Success rates of endotracheal intubation using the standard method versus the modified-ramped position.

Background: The sniffing position used in intubation has disadvantages, including suboptimal glottic view, respiratory problems, increased risk of aspiration, and pain. In this regard, we have proposed new conditions to facilitate intubation and tube placement in patients with a Mallampati score higher than 2, by introducing a new position called the modified rapid airway management positioner (RAMP) position. The authors compared various parameters to improve intubation conditions between these two positions. Methods: This intervention is a randomized clinical trial study, with a random sampling method that divides the patients into two groups: a control group placed in the standard position (S) and an intervention group placed in the modified (M) RAMP position. An anesthesiologist performed intubation. In group (S), patients were placed in the supine position as usual, and a pillow with a height of 10 cm was placed under their heads. In group (M), the patients were placed in the supine position on a modified RAMP with a triangular shape, 15 cm in height, and 80 cm in length, at a 30° angle. The pillow had lengths of 20 and 80 cm. Results: In the present study, 112 patients were investigated, consisting of 58 women (51.8%) and 54 men (48.2%). The intubation time in the intervention group using the modified RAMP roll technique was significantly shorter (51.25 s) compared to the control group using the standard method (88.39 s) (P=0.019). Conclusion: The results of the study showed that the modified RAMP roll improved the general conditions of intubation and led to a better view of the glottis in direct laryngoscopy. This is a very important aspect of intubation, and with a better view of the pharynx and glottis, the intubation procedure can be performed with higher quality, reducing the number of intubation attempts and the duration of the procedure.

Left Head Rotation as an Alternative to Difficult Tracheal Intubation: Randomized Open Label Clinical Trial.

BACKGROUND: Tracheal intubation is a life-saving intervention, and optimizing the patient's head and neck position for the best glottic view is a crucial step that accelerates the procedure. The left head rotation maneuver has been recently described as an innovative alternative to the traditional sniffing position used for tracheal intubation with marked improvement in glottic visualization. OBJECTIVE: This study compared the glottic view and intubating conditions in the sniffing position versus left head rotation during direct laryngoscopy. METHODS: This randomized, open-label clinical trial enrolled 52 adult patients admitted to Baguio General Hospital and Medical Center from September 2020 to January 2021 for an elective surgical procedure requiring tracheal intubation under general anesthesia. Intubation was done using a 45° left head rotation in the experimental group (n=26), while the control group (n=26) was intubated using the conventional sniffing position. Glottic visualization and intubation difficulty with the two procedures were assessed using the Cormack-Lehane grade and Intubation Difficulty Scale, respectively. Successful intubation is measured by observing a capnographic waveform in the end-tidal CO2 monitor after placement of the endotracheal tube. RESULTS: There was no statistically significant difference in the Cormack-Lehane grade, with 85% (n=44) of patients classified under grades 1 (n=11 and n=15) and 2 (n=11 and n=7) in the left head rotation and sniffing position groups, respectively. In addition, there were no statistically significant differences in the Intubation Difficulty Scale scores of patients intubated with left head rotation or sniffing position; 30.7% (n=8) of patients in both groups were easily intubated, while 53.8% (n=14) in left head rotation and 57.6% (n=15) in sniffing position groups were intubated with slight difficulty. Similarly, there were no significant differences between the 2 techniques in any of the 7 parameters of the Intubation Difficulty Scale, although numerically fewer patients required the application of additional lifting force (n=7, 26.9% vs n=11, 42.3%) or laryngeal pressure (n=3, 11.5% vs n=7, 26.9%) when intubated with left head rotation. The intubation success rate with left head rotation was 92.3% versus 100% in the sniffing position, but this difference was not statistically significant. CONCLUSIONS: Left head rotation produces comparable laryngeal exposure and intubation ease to the conventional sniffing position. Therefore, left head rotation may be an alternative for patients who cannot be intubated in the sniffing position, especially in hospitals where advanced techniques such as video laryngoscopes and flexible bronchoscopes are unavailable, as is the case in this study. However, since our sample size was small, studies with a larger study population are warranted to establish the generalizability of our findings. In addition, we observed inadequate familiarity among anesthesiologists with the left head rotation technique, and the intubation success rate may improve as practitioners attain greater technical familiarization. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number (ISRCTN)ISRCTN23442026; https://www.isrctn.com/ISRCTN23442026.

An approach to define newborns´ sniffing position using an angle based on reproducible facial landmarks.

BACKGROUND: The neutral or sniffing position is advised for mask ventilation in neonates to avoid airway obstruction. As definitions are manifold and often unspecific, we wanted to investigate the reliability and reproducibility of angle measurements based on facial landmarks that may be used in future clinical trials to determine a hypothetical head position with minimal airway obstruction during mask ventilation. METHODS: In a prospective single-center observational study, 2D sagittal photographs of 24 near-term and term infants were taken, with five raters marking facial landmarks to assess interobserver agreement of those landmarks and angle δ, defined as the angle between the line parallel to the lying surface and the line crossing Subnasale (Sn) and Porion' (P'). Angle δ was assessed in sniffing (δsniff ) and physiologic (δphys ) head position, the former based on a published, yet poorly defined head position where the tip of the nose aligns to the ceiling with the head in a supine, relaxed mid-position. RESULTS: Infants had a mean (SD) gestational age of 37.3 (2.3) weeks. Angle δ could be determined in all 48 images taken in either the sniffing or the physiological head position. Interobserver correlation coefficient was 98.6 for all measurements independent of head position. Angle δsniff was 90.5° (5.7) in the sniffing position. CONCLUSIONS: This study provides a new measuring technique using an angle that is reproducible and reliable and may be used in future studies to correlate head position with airway obstruction.

[A comparison of ramping position and sniffing position during endotracheal intubation: a systematic review and meta-analysis]. / Comparação entre a posição de rampa e posição olfativa durante intubação traqueal: revisão sistemática e meta­análise.

OBJECTIVES: Positioning during endotracheal intubation (ETI) is critical to ensure its success. We aimed to determine if the ramping position improved laryngeal exposure and first attempt success at intubation when compared to the sniffing position. METHODS: PubMed, EMBASE, and Cochrane CENTRAL databases were searched systematically from inception until January 2020. Our primary outcomes included laryngeal exposure as measured by Cormack-Lehane Grade 1 or 2 (CLG 1/2), CLG 3 or 4 (CLG 3/4), and first attempt success at intubation. Secondary outcomes were intubation time, use of airway adjuncts, ancillary maneuvers and complications during ETI. RESULTS: Seven studies met our inclusion criteria, of which 4 were RCTs and 3 were cohort studies. The meta-analysis was conducted by pooling the effect estimates for all 4 included RCTs (n=632). There were no differences found between ramping and sniffing positions for odds of CLG 1/2, CLG 3/4, first attempt success at intubation, intubation time, use of ancillary airway maneuvers and use of airway adjuncts, with evidence of high heterogeneity across studies. However, the ramping position in surgical patients is associated with increased likelihood of CLG 1/2 (OR=2.05, 95% CI 1.26 to 3.32, p=0.004) and lower likelihood of CLG 3/4 (OR=0.49, 95% CI 0.30 to 0.79, p=0.004), moderate quality of evidence. CONCLUSION: Our meta-analysis demonstrated that the ramping position may benefit surgical patients undergoing ETI by improving laryngeal exposure. Large-scale well-designed multicentre RCTs should be carried out to further elucidate the benefits of the ramping position in the surgical and intensive care unit patients.

A comparison of ramping position and sniffing position during endotracheal intubation: a systematic review and meta-analysis / Comparação entre a posição de rampa e posição olfativa durante intubação traqueal: revisão sistemática e meta-análise

Abstract Objectives Positioning during endotracheal intubation (ETI) is critical to ensure its success. We aimed to determine if the ramping position improved laryngeal exposure and first attempt success at intubation when compared to the sniffing position. Methods PubMed, EMBASE, and Cochrane CENTRAL databases were searched systematically from inception until January 2020. Our primary outcomes included laryngeal exposure as measured by Cormack-Lehane Grade 1 or 2 (CLG 1/2), CLG 3 or 4 (CLG 3/4), and first attempt success at intubation. Secondary outcomes were intubation time, use of airway adjuncts, ancillary maneuvers, and complications during ETI. Results Seven studies met our inclusion criteria, of which 4 were RCTs and 3 were cohort studies. The meta-analysis was conducted by pooling the effect estimates for all 4 included RCTs (n = 632). There were no differences found between ramping and sniffing positions for odds of CLG 1/2, CLG 3/4, first attempt success at intubation, intubation time, use of ancillary airway maneuvers, and use of airway adjuncts, with evidence of high heterogeneity across studies. However, the ramping position in surgical patients is associated with increased likelihood of CLG 1/2 (OR = 2.05, 95% CI 1.26 to 3.32, p = 0.004) and lower likelihood of CLG 3/4 (OR = 0.49, 95% CI 0.30 to 0.79, p = 0.004), moderate quality of evidence. Conclusion Our meta-analysis demonstrated that the ramping position may benefit surgical patients undergoing ETI by improving laryngeal exposure. Large scale well designed multicentre RCTs should be carried out to further elucidate the benefits of the ramping position in the surgical and intensive care unit patients.

Resumo Objetivos A posição do paciente durante a Intubação Traqueal (IT) é fundamental para o sucesso do procedimento. Nosso objetivo foi determinar se a posição de rampa melhorou a visualização laríngea e o êxito na primeira tentativa de intubação quando comparada à posição olfativa. Métodos Os bancos de dados PubMed, EMBASE e Cochrane CENTRAL foram pesquisados de forma sistemática a partir da data em que os bancos de dados foram estabelecidos até janeiro de 2020. Nossos desfechos primários incluíram a visualização laríngea avaliada como Cormack‐Lehane Grau 1 ou 2 (CLG 1/2), Cormack‐Lehane Grau 3 ou 4 (CLG 3/4) e o êxito na primeira tentativa de intubação. Os desfechos secundários foram o tempo de intubação, uso de dispositivos adjuvantes para manuseio de vias aéreas, manobras auxiliares e complicações durante a IT. Resultados Sete estudos preencheram nossos critérios de inclusão, dos quais 4 eram Estudos Clínicos Randomizados (ECR) e 3 eram estudos de coorte. A meta‐análise foi conduzida combinando as estimativas de efeito para todos os 4 ECR incluídos (n = 632). Não foram encontradas diferenças entre as posições de rampa e olfativa para razão de chances de CLG 1/2, CLG 3/4, sucesso na primeira tentativa de intubação, tempo de intubação, uso de manobras auxiliares das vias aéreas e uso de dispositivos adjuvantes de vias aéreas, havendo evidência de alta heterogeneidade nos estudos. No entanto, a posição de rampa em pacientes cirúrgicos está associada com maior probabilidade de CLG 1/2 (OR = 2,05; 95% IC 1,26 a 3,32; p = 0,004) e menor probabilidade de CLG 3/4 (OR = 0,49; 95% IC 0,30 a 0,79; p = 0,004), com qualidade moderada de evidência. Conclusão Nossa meta‐análise demonstrou que a posição de rampa pode beneficiar pacientes cirúrgicos submetidos a IT, melhorando a visualização laríngea. ECR multicêntricos bem projetados com amostras grandes devem ser realizados para esclarecer ainda mais os benefícios da posição de rampa nos pacientes cirúrgicos e na unidade de terapia intensiva.

Comparison of ease of intubation in sniffing position and further neck flexion.

BACKGROUND AND AIMS: Optimization of patient's head and neck position for the best laryngeal view is the most important step before laryngoscopy and intubation. The objective of this prospective crossover study was to determine the differences, if any, between the gold standard sniffing position (SP) and the further head elevation (HE) (neck flexion) with regard to the incidence of difficult laryngoscopy, intubation difficulty, and variables of the I ntubation Difficulty Scale (IDS) in adult patients undergoing elective surgery under general anesthesia. MATERIAL AND METHODS: In the "SP" the neck must be flexed on the chest by elevating the head with a cushion under the occiput and extending the head at the atlanto-occipital joint. Our study was carried out to evaluate the glottic view in SP compared to further HE by 1.5 inches during direct laryngoscopy in elective surgeries. Patients were randomly assigned to either Group A ("SP" during first laryngoscopy and "HE" during second laryngoscopy) or vice versa in Group B. The effect of patient position on ease of intubation was assessed using a quantitative scale - The intubation difficulty scale (IDS). RESULTS: There were significant differences with regard to glottic visualization (P = 0.00), number of operators (P = 0.001), laryngeal pressure (P = 0.00), and lifting force (P = 0.00) required for intubation and IDS (P = 0.00), thus favoring further HE position. CONCLUSION: We conclude that the HE position is superior to standard SP with regard to ease of intubation as assessed by IDS.

A Randomized Study Comparing the Sniffing Position with Simple Head Extension for Glottis Visualization and Difficulty in Intubation during Direct Laryngoscopy.

BACKGROUND: Proper positioning of the head and neck is important for an optimal laryngeal visualization. Traditionally, sniffing position (SP) is recommended to provide a superior glottic visualization, during direct laryngoscopy, enhancing the ease of intubation. Various studies in the last decade of this belief have challenged the need for sniffing position during intubation. We conducted a prospective study comparing the sniffing head position with simple head extension to study the laryngoscopic view and intubation difficulty during direct laryngoscopy. MATERIALS AND METHODS: Five-hundred patients were included in this study and randomly distributed to SP or simple head extension. In the sniffing group, an incompressible head ring was placed under the head to raise its height by 7 cm from the neutral plane followed by maximal extension of the head. In the simple extension group, no headrest was placed under the head; however, maximal head extension was given at the time of laryngoscopy. Various factors as ability to mask ventilate, laryngoscopic visualization, intubation difficulty, and posture of the anesthesiologist during laryngoscopy and tracheal intubation were noted. In the incidence of difficult laryngoscopy (Cormack Grade III and IV), Intubation Difficulty Scale (IDS score) was compared between the two groups. RESULTS: There was no significant difference between two groups in Cormack grades. The IDS score differed significantly between sniffing group and simple extension group (P = 0.000) with an increased difficulty during intubation in the simple head extension. Patients with simple head extension needed more lifting force, increased use of external laryngeal manipulation, and an increased use of alternate techniques during intubation when compared to SP. CONCLUSION: We conclude that compared to the simple head extension position, the SP should be used as a standard head position for intubation attempts under general anesthesia.

Man behind the laryngoscopy is important.

Tracheal intubation is the most fundamental and effective resuscitation skill in many emergency situations. It is also performed to facilitate various surgical procedures and mechanical ventilation in critically ill patients. Tracheal intubation is also one of the most commonly taught clinical skills.

Comparison of the conventional Macintosh laryngoscope, the Pentax Airwayscope, and the McGrath MAC video laryngoscope under restricted cervical motion: a manikin study.

Aim: We compared the utility of the conventional Macintosh laryngoscope, the Pentax Airway Scope, and the McGrath MAC video laryngoscope under restricted cervical motion using a manikin. Methods: We recruited 36 participants into the simulation study. The manikin's cervical motion was restricted with a cervical collar and a head immobilizer, as occurs in trauma cases. We recorded the time to intubation and the success rate of the intubations. Results: Data are medians and ranges. The time to intubation under normal and restricted cervical motion were 22.5 (10-78) and 23 (9-119) s with the Macintosh laryngoscope, 13.5 (5-50) and 14 (7-119) s with the Airway Scope, and 13 (6-32) and 18 (7-80) s with the McGrath MAC video laryngoscope. The differences in the time to intubation between normal and restricted cervical motion were significant only with the McGrath MAC (P = 0.0008). With restricted cervical motion, the times to intubation in the Airway Scope attempts were significantly shorter than those in the Macintosh laryngoscope (P = 0.0005) and McGrath MAC (P = 0.0282) attempts. The success rates under normal and restricted cervical motion were 100% and 80.6% with the Macintosh laryngoscope (P = 0.0054), 100% and 100% with the Airway Scope, and 100% and 97.2% with the McGrath MAC, respectively. Conclusion: In the present study, the Airway Scope was the best among the three devices. However, the differences between the Airway Scope and the McGrath MAC video laryngoscope may not be serious in a clinical situation. Data were gathered using a manikin, and further studies will be necessary.

Head elevation improves laryngeal exposure with direct laryngoscopy.

STUDY OBJECTIVE: The aim of this study was to examine the effect of changing head position on the laryngeal view in the same subject. DESIGN: Prospective, randomized, crossover comparison of laryngeal views. SETTING: Operating suite at a university-affiliated, community hospital. PATIENTS: One hundred sixty-seven consenting adult patients scheduled to undergo elective surgery with general anesthesia. INTERVENTIONS: After anesthesia induction and muscle relaxation and the head in extended position, the laryngeal view was graded in 3 different head height positions. A special inflatable pillow was placed under the subject's head before induction and was deflated to produce no head elevation or inflated to produce either 6.0cm (sniffing position), or 10.0cm elevation (elevated sniffing position) in random order. MAIN RESULTS: The incidence of difficult laryngoscopy (grade ≥3) was 8.38% with no head elevation, 2.39% in the sniffing position, and 1.19% in the elevated sniffing position. Head elevation was not associated with a worse grade in any single patient. CONCLUSIONS: Sniffing position improves glottic exposure when the laryngoscopic grade is greater than 1 in the head-flat position. The elevated sniffing position improves the view to a better grade in some patients. Because head elevation was not associated with a worse grade in any subject, the elevated sniffing position should be considered as the initial head position before direct laryngoscopy when a difficult exposure is anticipated.

Age and gender are important considerations in choosing the sniffing position for laryngoscopic view.

AIMS: The sniffing position is considered to be the standard position for direct laryngoscopic viewing. This crossover study evaluated age and gender as variables in comparing the benefits of the sniffing position over simple head extension for laryngeal view during direct laryngoscopy. METHODS: Laryngoscopy with a curved blade was performed on 200 anesthetized adults (100 males, 100 females) presenting for routine elective surgery. Glottic visualization was assessed by using the percentage of glottic opening (POGO) score in both simple extension and sniffing positions without the aid of the assistant or external laryngeal manipulation. Each gender group was divided into a younger group (< 50 years) and an older group (≥ 50 years). POGO scores were compared between both positions within each group. RESULTS: Mean (SD) POGO scores increased significantly only in younger male patients from 43% (39%) in the head extension position to 76% (30%) in the sniffing position. CONCLUSION: The sniffing position seems to be advantageous for getting a better laryngeal view during laryngoscopy for tracheal intubation in adult male patients less than 50 years old.

A Remote-Controlled Airbag Device Can Improve Upper Airway Collapsibility by Producing Head Elevation With Jaw Closure in Normal Subjects Under Propofol Anesthesia.

Continuous maintenance of an appropriate position of the mandible and head purely by manual manipulation is difficult, although the maneuver can restore airway patency during sleep and anesthesia. The aim of this paper was to examine the effect of head elevation with jaw closure using a remote-controlled airbag device, such as the airbag system, on passive upper airway collapsibility during propofol anesthesia. Seven male subjects were studied. Propofol infusion was used for anesthesia induction and maintenance, with a target blood propofol concentration of 1.5-2 [Formula: see text]g/ml. Nasal mask pressure ([Formula: see text]) was intermittently reduced to evaluate upper airway collapsibility (passive [Formula: see text]) and upstream resistance ([Formula: see text]) at three different head and jaw positions, jaw opening position in the supine position, jaw opening position in the sniffing position with 6-cm head elevation, and jaw closure at a 6-cm height sniffing position. The 6-cm height sniffing position with jaw closure was achieved by an airbag device that was attached to the subject's head-like headgear. Patient demographics, [Formula: see text] and [Formula: see text] in each condition were compared using one-way ANOVA with a post hoc Tukey test. [Formula: see text] was considered significant. We also confirmed the effects of our airbag device on improvement of upper airway collapsibility in three obstructive sleep apnea patients in a clinical study. The combination of 6-cm head elevation with jaw closure using the air-inflatable robotic airbag system decreased upper airway collapsibility ([Formula: see text]-cm H[Formula: see text]O) compared with the baseline position ([Formula: see text]-cm H[Formula: see text]O, [Formula: see text]). In the clinical study, there was improvement of upper airway obstruction in sleep apnea patients, including decreased apnea and hypopnea duration and increased the lowest level of oxygen saturation. We demonstrated that establishment of head elevation with jaw closure achieved by a remote-controlled airbag device using an inflatable airbag system can produce substantial decreases in upper airway collapsibility and maintain upper airway patency during propofol anesthesia and sleep.

Comparison of the ease of laryngeal mask airway ProSeal insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway.

BACKGROUND: The sniffing position is recommended for conventional laryngeal mask airway (LMA) insertion. However, there has been a high success rate of LMA insertion with the head in the neutral position. The effect of a difficult airway on the ease of LMA insertion is not clear. In this study, we compared the ease of LMA ProSeal™ (PLMA) insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway. METHODS: After obtaining informed consent from the subjects, we enrolled 144 adult patients (age range: 18-65) with an ASA physical status 1 or 2. After evaluation of the airway, all the patients were grouped into the EA (easy airway) group (n = 68) and the DA (difficult airway) group (n = 76). According to the head position, each group was divided into the EA-SE (extension) group (n = 35), the EA-SN (sniffing) group (n = 33), the DA-SE group (n = 39) and the DA-SN group (n = 37). The success rate and insertion time at the first attempt were evaluated. The position of the PLMA was fiberoptically scored from the mask aperture of the airway tube in the original head position. After the head position was changed to the sniffing and neutral positions in the SE and SN group, respectively, the position of PLMA was re-evaluated fiberoptically. RESULTS: The success rate and insertion time at the first attempt and the fiberoptic score showed no significant difference among the groups. After head position was changed, there were no significant changes in the fiberopitc scores. CONCLUSIONS: A difficult airway and the head position had no influence on the ease of PLMA insertion and the fiberopic score. Therefore, the head position can be selected according to the individual patient's situation.

Comparison of the ease of laryngeal mask airway ProSeal insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway / 대한마취과학회지

BACKGROUND: The sniffing position is recommended for conventional laryngeal mask airway (LMA) insertion. However, there has been a high success rate of LMA insertion with the head in the neutral position. The effect of a difficult airway on the ease of LMA insertion is not clear. In this study, we compared the ease of LMA ProSeal(TM) (PLMA) insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway. METHODS: After obtaining informed consent from the subjects, we enrolled 144 adult patients (age range: 18-65) with an ASA physical status 1 or 2. After evaluation of the airway, all the patients were grouped into the EA (easy airway) group (n = 68) and the DA (difficult airway) group (n = 76). According to the head position, each group was divided into the EA-SE (extension) group (n = 35), the EA-SN (sniffing) group (n = 33), the DA-SE group (n = 39) and the DA-SN group (n = 37). The success rate and insertion time at the first attempt were evaluated. The position of the PLMA was fiberoptically scored from the mask aperture of the airway tube in the original head position. After the head position was changed to the sniffing and neutral positions in the SE and SN group, respectively, the position of PLMA was re-evaluated fiberoptically. RESULTS: The success rate and insertion time at the first attempt and the fiberoptic score showed no significant difference among the groups. After head position was changed, there were no significant changes in the fiberopitc scores. CONCLUSIONS: A difficult airway and the head position had no influence on the ease of PLMA insertion and the fiberopic score. Therefore, the head position can be selected according to the individual patient's situation.

The changes of the sternomental distance under general anesthesia and with increasing age

BACKGROUND: Because the sternomental distance (SMD) is evaluated in conscience patients and in the sitting position, this could change under general anesthesia, which is a state that the patient is unconscious and fully relaxed in the supine position. Increasing age also affects the SMD. We investigated the change in the SMD with the patients under general anesthesia and we also investigated the effect of age on the SMD. METHODS: A total of 108 patients were allocated to Group Y (20-30 yr), Group M (31-50 yr) and Group O (51-70 yr). The SMD, as measured when the patients were awake and sitting, was defined as baseline. The SMD was measured in the supine position, the shoulder-suppressed supine position, at the time of loss of consciousness (LOC), 4 min after vecuronium administration and in the sniffing position. The percent change of the SMD (%) was defined as (the baseline SMD - the measured SMD)/the baseline SMD x 100. RESULTS: Compared with the baseline, the SMD decreased significantly in the supine position, the shoulder-suppressed supine position, at the time of LOC, during neuromuscular blockade and in the sniffing position in all the groups. Group O showed a shorter SMD than did Groups Y and M for all the measurements. There was no significant difference in the percent change of the SMD between the groups. CONCLUSIONS: This study demonstrated that the SMD was significantly reduced by the supine position, the sniffing position, at the time of loss of consciousness and during neuromuscular blockade with the patient under general anesthesia and also with the increasing age of the patient.

Randomized Study Comparing the Sniffing Position with the Neutral Position for Lightwand Intubation / 대한마취과학회지

BACKGROUND: The sniffing position is recommended for optimal glottic visualization under direct laryngoscopy. However, there is no study assessing whether sniffing position is superior to a neutral position during lightwand-guided intubation. This prospective, randomized study was performed to compare facilitation of lightwand-guided intubation between the sniffing and neutral positions. METHODS: The study included 180 patients with normal cervical spines requiring tracheal intubation for elective surgery. Patients were randomly allocated into two groups: neutral or sniffing position. Mallampati class, mouth opening distance, thyromental distance, and laryngeal view grade were measured. A lightwand railroaded with an endotracheal tube was bent 90degrees at 5 cm from the distal end for both groups. Time to intubation, success rate and intubation time for the first attempt, hydrodynamic changes, and BIS values were recorded. RESULTS: There were no significant differences in time to intubation, success rate and intubation time of the first trial, hydrodynamic changes, or BIS values between the two positions. CONCLUSIONS: Routine use of the sniffing position does not provide any advantage over the neutral position during lightwand-guided intubation.

Sniffing Position Improves the Laryngeal View Regardless of Body Mass Index / 대한마취과학회지

BACKGROUND: Most anesthesiologists universally recommend the sniffing position and consider it to be essential for improving the performance of orotracheal intubation. However, a recent investigation reported that the sniffing position does not aid the laryngoscope except under specific circumstances (i.e., obesity). Therefore, this study examined the impact of the BMI (body mass index) on the effectiveness of the sniffing position in improving the laryngeal view. METHODS: A video laryngoscopy imaging system and POGO (the percentage of glottic opening) scoring system were used to assess the laryngeal view in 79 adult patients undergoing a laryngoscopy. In each patient, the laryngeal view was videotaped continuously from simple head extension to the sniffing position by inflating a pressure bag as a pillow to obtain approximately 15o of flexion of the lower cervical spine on the chest. The variables assessed included the BMI, the POGO score in each position and the change in the POGO score. RESULTS: The POGO scores improved with the sniffing position (18.1 +/- 14.3%). However, the sniffing position did not improve the POGO score in 16/79 (20.3%) patients. The sniffing position did not worsen the POGO score in any patient. No significant correlation was found between the BMI and the change in the POGO score in the sniffing position (Pearson's correlation coefficient r = 0.075). CONCLUSIONS: The sniffing position has the potential to improve the laryngeal view in all intubations without needing to consider the BMI. Therefore, the sniffing position appears to be advantageous for orotracheal intubation compared with a simple head extension.

The Comparison of Suceess Rates of Lightwand Facilitated Tracheal Intubation in Different Head Positions (Neutral Position versus Sniffing Position) / 대한마취과학회지

BACKGROUND: It has been known that a patient head in sniffing position for lightwand facilitated tracheal intubation is not an anatomically appropriate method. However, there is no evidence nor study whether it is true or not. In this study, we compared success rates of lightwand facilitated tracheal intubation in neutral position versus sniffing position. METHODS: With informed consent, sixty adult patients of ASA physical status I or II were randomly allocated into two groups: neutral position (N) or sniffing position (S) group. A lightwand and tube were bent at approximately a 90degrees degree angle for N group and a 60 degree angle for S group on the basis of mouth axis and pharyngeal axis. The time to intubation, success rates of 1st trial of intubation, overall intubation success rates, hemodynamic changes and complications during the procedure were recorded. RESULTS: There was no significant difference in the time to intubation, success rates of 1st trial of intubation, overall intubation success rates, hemodynamic changes and complications between neutral position and sniffing position groups. CONCLUSIONS: Success rates of lightwand facilitated tracheal intubation in neutral position versus sniffing position showed no significant difference. Therefore, both positions are suitable for lightwand assisted intubation.

The Comparison of Suceess Rates of Lightwand Facilitated Tracheal Intubation in Different Head Positions (Neutral Position versus Sniffing Position) / 대한마취과학회지

BACKGROUND: It has been known that a patient head in sniffing position for lightwand facilitated tracheal intubation is not an anatomically appropriate method. However, there is no evidence nor study whether it is true or not. In this study, we compared success rates of lightwand facilitated tracheal intubation in neutral position versus sniffing position. METHODS: With informed consent, sixty adult patients of ASA physical status I or II were randomly allocated into two groups: neutral position (N) or sniffing position (S) group. A lightwand and tube were bent at approximately a 90degrees degree angle for N group and a 60 degree angle for S group on the basis of mouth axis and pharyngeal axis. The time to intubation, success rates of 1st trial of intubation, overall intubation success rates, hemodynamic changes and complications during the procedure were recorded. RESULTS: There was no significant difference in the time to intubation, success rates of 1st trial of intubation, overall intubation success rates, hemodynamic changes and complications between neutral position and sniffing position groups. CONCLUSIONS: Success rates of lightwand facilitated tracheal intubation in neutral position versus sniffing position showed no significant difference. Therefore, both positions are suitable for lightwand assisted intubation.