Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study

Liaskou, Chara; Vouzounerakis, Eleftherios; Trikoupi, Anastasia; Staikou, Chryssoula

doi:10.1016/j.bjane.2020.04.021

Acessibilidade / Reportar erro

Brasil

Revista Brasileira de Anestesiologia

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Clinical Research • Rev. Bras. Anestesiol. 70 (2) • Mar-Apr 2020 • https://doi.org/10.1016/j.bjane.2020.04.021 copy

Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study^☆ ☆ The study was carried out in two hospitals, General Hospital of Rethymno and George Papanikolaou General Hospital in Thessaloniki.

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Background and objectives:

The prediction of difficult laryngoscopy is based on tests that assess anatomic characteristics of face and neck. We aimed to identify the most accurate tests and propose a multivariate predictive model.

Methods:

This prospective observational study included 1134 patients. Thyromental Distance (TMD), Sternomental Distance (STMD), Ratio of Height-to-Thyromental Distance (R-H/TMD), Neck Circumference (NC), Ratio of Neck Circumference-to-Thyromental Distance (R-NC/TMD), Hyomental Distance with head in Neutral Position (HMD-NP) and at Maximal Extension (HMD-HE), Ratio of Hyomental Distance at Maximal head extension-to-hyomental distance in neutral position (R-HMD), Mallampati Class (MLC), Upper Lip Bite Test (ULBT), Mouth Opening (MO) and Head Extension (HE) were assessed preoperatively. A Cormack-Lehane Grade ≥ 3 was defined as Difficult Laryngoscopy. Sensitivity, specificity, positive and negative predictive values were assessed for all tests. Multivariate analysis with logistic regression was used to create the predictive models.

Results:

A model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed high prognostic accuracy; x²(5) = 109.12, p < 0.001, AUC = 0.86, p < 0.001). Its sensitivity, specificity and negative predictive value were 82.3%, 74.8% and 97.4%, respectively. A second model including two measurements not requiring patient's cooperation (R-NC/TMD and HMD-HE) exhibited good prognostic performance; x²(2) = 63.5, p < 0.001, AUC = 0.77, p < 0.001. Among single tests, HE had the highest sensitivity (78.5%) and negative predictive value (96%).

Conclusions:

A five-variable model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed satisfyingly high predictive value for difficult laryngoscopy. A model including R-NC/TMD and HMD-HE could be useful in incapable patients. The most accurate single predictor was HE.

KEYWORDS
Airway assessment; Difficult laryngoscopy; Predictive tests; Predictive multivariate model; Sensitivity and specificity

Measured anatomic features	Definition/Measurement	Conditions
TMD (cm)	Defined as the straight-line distance (cm) from the lower border of the thyroid notch to the bony point of the mentum	Head extended
TMD (cm)		Closed mouth
STMD (cm)	Defined as the straight-line distance (cm) from the bony point of the mentum to the upper border of the manubrium sterni	Head extended
STMD (cm)		Closed mouth
NC (cm)	Measured at the level of the thyroid cartilage	Head in neutral position
R-H/TMD	Each patient's height (cm) was recorded in order to calculate the R-H/TMD
R-NC/TMD	Each patient's NC (cm) was recorded in order to calculate the R-NC/TMD
HMD-NP (cm)	Distance (cm) from the tip of the hyoid bone to the anterior part of the mentum	Head in neutral position
		Mouth closed
		Without swallowing
HMD-HE (cm)	Distance (cm) from the tip of the hyoid bone to the anterior part of the mentum	Head maximally extended
HMD-HE (cm)		Without lifting the shoulders
R-HMD	Defined as the ratio of the HMD at extreme head extension to the HMD measured with the head in the neutral position
MLC	Class 1: soft palate, fauces, entire uvula, anterior and posterior tonsillar pillars visible	Sitting position
	Class 2: soft palate, fauces, uvula visible	Head in neutral position
	Class 3: soft palate and base of uvula visible	Mouth wide open with tongue fully protruding
	Class 4: only hard palate visible.	Without phonation
ULBT	Class 1: lower incisors can bite the upper lip above the vermilion line
	Class 2: lower incisors can bite the upper lip below the vermilion line
	Class 3: lower incisors cannot bite the upper lip
MO (cm)	Measured with the mouth fully open (cm)
HE (º)	Reference points: angle of the jaw and upper incisor teeth. Measuring side of the goniometer moved parallel to the upper incisors, and maximum extension recorded	Sitting position
HE (º)		Head maximally extended

Patients' characteristics	Values
Men	560 (49.4%)
Women	574 (50.4%)
Age (years)	49.4 ± 18.4
Weight (kg)	75.8 ± 14.2
Height (cm)	169.4 ± 9
Body Mass Index (BMI, kg. m^-2)	26.4 ± 4
Cormack-Lehane grade 1	849 (74.9%)
Cormack-Lehane grade 2	166 (14.6%)
Cormack-Lehane grade 3	86 (7.6%)
Cormack-Lehane grade 4	33 (2.9%)

Variables included in the equation due to statistical significance
	B	S.E.	Odds Ratio	95% C.I.	p-value
MLC	0.56	0.14	1.75	1.32-2.32	< 0.001
ULBT	0.8	0.21	2.22	1.48-3.34	< 0.001
R-NC/TMD	0.7	0.22	2	1.31-3.1	0.01
HE	-0.06	0.02	0.94	0.9-0.98	0.002
HMD-HE	-0.6	0.16	0.55	0.4-0.75	< 0.001
Constant	-2.45	1.8	0.09		0.17
x²(5) = 109.12, p< 0.001
AUC
Area	0.86
95% CI	0.82-0.9
p-value	< 0.001
Variables not included in the equation due to lack of statistical significance
	Score			p-value
MO	3.43			0.06
TMD	1.15			0.28
STMD	0.002			0.96
R-H/TMD	0.3			0.58
NC	1.25			0.26
HMD-NP	0.72			0.4
R-HMD	0.4			0.84

Variables included in the equation due to statistical significance
	B	S.E.	Odds Ratio	95% C.I.	p-value
R-NC/TMD	0.81	0.19	2.25	1.56-3.25	< 0.001
HMD-HE	-0.7	0.15	0.5	0.37-0.67	< 0.001
Constant	-2.37	1.37	0.09		0.08
x² (2) = 63.5, p< 0.001
AUC
Area	0.77
95% CI	0.74-0.8
p-value	< 0.001
Variables not included in the equation due to lack of statistical significance
	Score			p- value
TMD	2.69			0.1
STMD	1.56			0.21
R-H/TMD	0.05			0.82
NC	3.08			0.08
HMD-NP	0.87			0.35
R-HMD	0.08			0.78

Predictive test	Cut-off value	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	AUC mean (95% CI)	p
TMD (cm)	≤ 7.5	38.7	85	23.2	92.2	0.64 (0.61-0.687)	< 0.001
TMD male	≤ 8	45.7	83.6	24	92.9
TMD female	< 7	48.9	86.86	30.4	93.6
STMD (cm)	≤ 17	68.9	54.7	15.1	93.7	0.67 (0.64-0.7)	< 0.001
STMD male	≤ 18.5	81.43	48.98	15.8	95.7
STMD female	≤ 15	48.98	80.19	22.5	93.1
R-H/TMD	> 21.25	47.1	81.6	23.1	92.9	0.66 (0.63-0.69)	< 0.001
R-H/TMD male	> 21.25	38.57	85.71	24.1	92.2
R-H/TMD female	> 21.6	55.1	81.9	26.3	94
NC (cm)	> 38	70.6	49.6	14.1	93.5	0.61 (0.59-0.64)	< 0.001
NC male	> 40.5	72.86	39.59	12.4	92.6
NC female	> 38.5	44.9	82.67	23.3	92.7
R-NC/TMD	> 4.94	52.9	78.7	22.6	93.4	0.69 (0.66-0.72)	< 0.001
R-NC/TMD male	> 4.94	51.43	75.7	19.5	92.9
R-NC/TMD female	> 4.81	61.2	78.29	24.9	94.5
HMD-HE (cm)	≤ 5.5	73.8	60.3	17.9	95.2	0.71 (0.68-0.74)	< 0.001
HMD-HE male	≤ 5.5	66.67	67.8	19.5	94.5
HMD-HE female	≤ 5	84.62	58.56	19.3	97
HMD-NP (cm)	≤ 4.5	73.8	58	17.1	95	0.7 (0.66-0.73)	< 0.001
HMD-NP male	≤ 4.5	64.1	64.7	17.6	93.9
HMD-NP female	≤ 4	84.6	57.46	18.9	97
R-HMD	> 1.2	73.8	54	15.9	94.6	0.66 (0.63-0.7)	< 0.001
R-HMD male	> 1.2	64.1	59.4	15.6	93.4
R-HMD female	> 1.22	88.46	53.87	18.4	97.5
MO (cm)	≤ 3.8	53.4	74.7	19.9	93.2	0.69 (0.66-0.72)	< 0.001
MO male	≤ 4.4	77.1	52	15.9	95.1
MO female	≤ 3.7	51	78.1	21.5	93.1
HE (º)^a a The cut-off point for HE was same for males and females.	≤ 35	78.5	60.4	18.9	96	0.72 (0.69-0.75)	< 0.001

Sociedade Brasileira de Anestesiologia R. Professor Alfredo Gomes, 36, 22251-080 Botafogo RJ Brasil, Tel: +55 21 2537-8100, Fax: +55 21 2537-8188 - Campinas - SP - Brazil
E-mail: bjan@sbahq.org

Acompanhe os números deste periódico no seu leitor de RSS

[1] * Corresponding author. E-mail: charaliaskou@gmail.com (C. Liaskou).

Brasil

Brasil

Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study☆ ☆ The study was carried out in two hospitals, General Hospital of Rethymno and George Papanikolaou General Hospital in Thessaloniki.

Abstract

Background and objectives:

Methods:

Results:

Conclusions:

Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study^☆ ☆ The study was carried out in two hospitals, General Hospital of Rethymno and George Papanikolaou General Hospital in Thessaloniki.