The experience of Xiaowu school laryngeal mask (4)

Xiao Wuxue's experience of laryngeal mask (4) Recently, I was very fortunate to participate in the "Panorama Airway 2022CAA Cloud Classroom of Li Wenwen Team of the Airway Management Training Center of the Eye and ENT Hospital Affiliated to Fudan University" and learn from all the airway management experts.
I am very serious and responsible.
I have learned a lot.
The laryngeal mask is really not a tool that is tasteless and discarded.
If the laryngeal mask is used well, it can really solve many difficult clinical problems.
OK, let everyone follow my learning step by step.
Uncover the mystery of the laryngeal mask.
How to choose a model? Most SGAs are full-size (eg, 3, 4, 5, 6), but some SGAs also have half-size options (eg, 3.
5, 4.
5)
.

Although manufacturer's guidelines for use recommend size selection based on patient weight, these guidelines generally assume a standard body size
.

Predicting optimal size is complex because optimal seal depends on many factors, including device size, cuff inflation status, and patient anatomy
.

The SGA manufacturer provides guidance on maximum cuff inflation
.

The recommended cuff volumes for LMA size 4 and LMA size 5 are 30 mL and 40 mL, respectively
.

If a larger cuff volume is required to maintain a seal, we usually switch to a larger size LMA
.

With a larger LMA, a better seal may be achieved with less air charge
.

Using too small a device and overinflation of the cuff may result in poor fit within the oropharyngeal space and may also cause damage to the oropharyngeal mucosa
.

In general, a size 4 LMA is suitable for most adult women, and a size 5 LMA is suitable for adult men weighing up to 100kg
.

In conclusion, the choice of LMA model is both a science and an art
.

In many cases, if adequate ventilation cannot be achieved with the initially selected LMA size (eg, large leaks at any cuff volume), a different LMA size should be tried, or endotracheal intubation should be performed
.

Weight-based guide to choosing LMA sizeWeight, kgLMA sizeMax cuff volume, mL<5145-101.
5710-2021020-302.
51430-5032050-7043070-100540>100650Guide to choosing LMA size.
Note that these are guidelines only, and clinical judgment may be needed.
In general, the size-4 LMA will be suitable for most adult females, and the size-5 for adult males up to 100 kg.
The new size-6 is intended for adult patients over 100 kg.
The size-3 LMA is now considered to be a pediatric size.
Be careful not to exceed the maximum cuff inflation volume; if more than this volume is necessary to maintain a seal, consider the use of a larger size, as a better seal may be obtained by using a larger size with less air.
Using too small a mask and overinflating the cuff may result in a poor fit within the oropharyngeal space and may possibly injure the oropharyngeal mucosa.
Many clinicians measure the cuff pressure to ensure that it never exceeds 60 cmH2O (ie, 41 mmHg).
LMA: laryngeal mask airway; kg: kilogram; mL: milliliter; cmH2O: centimeter of water; mmHg: milliliter of mercury.
Reproduced with permission .
Copyright © 2015 Teleflex Incorporated.
All rights reserved.
Kilogram weight model newborn (<4 kg) size 1.
0 laryngeal mask infant (5～10 kg) 1.
5 laryngeal mask child (10～20 kg) 2.
0 laryngeal mask child (20 ~30 kg) No.
2.
5 Laryngeal Mask Adult (30-50 kg) No.
3.
0 Laryngeal Mask Adult (50-70 kg) No.
4.
0 Laryngeal Mask Adult (70-100 kg) No.
5.
0 Laryngeal Mask Adult (>100 kg) No.
6.
0 Laryngeal Mask hood children choose adults choose 16-20Kg, 2.
5 is more suitable for overweight children according to the actual weight of thin children according to the ideal weight (standard growth curve) can refer to: three finger method according to the instructions, according to the weight of women 4, men 5 overweight/obese ( BMI ≥ 25): Based on ideal body weight, anatomical structures can be referenced, such as nail-chin spacing indications and contraindications Laryngeal mask indications Contraindications 1.
For surgery without the risk of vomiting and refluxCopyright © 2015 Teleflex Incorporated.
All rights reserved.
Kilogram weight model newborn (<4 kg) size 1.
0 laryngeal mask infant (5～10 kg) 1.
5 laryngeal mask child (10～20 kg) 2.
0 laryngeal mask child (20～20 kg) 30 kg) No.
2.
5 Laryngeal Mask Adult (30-50 kg) No.
3.
0 Laryngeal Mask Adult (50-70 kg) No.
4.
0 Laryngeal Mask Adult (70-100 kg) No.
5.
0 Laryngeal Mask Adult (>100 kg) No.
6.
0 Laryngeal Mask Children choose 16-20Kg for adults, 2.
5 is more suitable for overweight children according to the actual weight.
Children according to the ideal weight (standard growth curve) can refer to: three finger method ≥25): Based on ideal body weight, you can refer to anatomical structures, such as nail-mind spacing indications and contraindications Laryngeal mask indications Contraindications 1.
For surgery without the risk of vomiting and refluxCopyright © 2015 Teleflex Incorporated.
All rights reserved.
Kilogram weight model newborn (<4 kg) size 1.
0 laryngeal mask infant (5～10 kg) 1.
5 laryngeal mask child (10～20 kg) 2.
0 laryngeal mask child (20～20 kg) 30 kg) No.
2.
5 Laryngeal Mask Adult (30-50 kg) No.
3.
0 Laryngeal Mask Adult (50-70 kg) No.
4.
0 Laryngeal Mask Adult (70-100 kg) No.
5.
0 Laryngeal Mask Adult (>100 kg) No.
6.
0 Laryngeal Mask Children choose 16-20Kg for adults, 2.
5 is more suitable for overweight children according to the actual weight.
Children according to the ideal weight (standard growth curve) can refer to: three finger method ≥25): Based on ideal body weight, you can refer to anatomical structures, such as nail-mind spacing indications and contraindications Laryngeal mask indications Contraindications 1.
For surgery without the risk of vomiting and reflux
.

LMA is an alternative to face mask ventilation and endotracheal intubation ventilation, however, LMA cannot replace endotracheal intubation if indicated for endotracheal intubation
.

2.
During emergency resuscitation (CRP), the insertion of the laryngeal mask is relatively simple, easy to use, and has a reliable effect, which can win every minute of precious time
.

3.
LMA is used to manage known or unpredictable difficult airways
.

   1.
Surgery without the risk of vomiting and reflux, especially in patients with difficult endotracheal intubation
.

2.
When difficult intubation forces the use of a laryngeal mask (LMA), the laryngeal mask can be used as a guide for endotracheal intubation
.

3.
Fiberoptic bronchoscope laser cauterization of vocal cords, trachea or small tumors in the bronchus can be performed through the laryngeal mask
.

4.
Laryngeal mask can be used for patients with unstable cervical spine who need to move their head but have great concerns
.

5.
Laryngeal mask is suitable for use in ophthalmic surgery, because it is less likely to cause increased intraocular pressure, less cough and vomiting after surgery, less reaction to laryngeal mask extraction, and less fluctuation of intraocular pressure
.

6.
The laryngeal mask can be used during emergency resuscitation.
If the operation is skilled, effective ventilation can be quickly established, and the effect is exact
.

7.
It is suitable for general anesthesia surgery of body surface and limbs that does not require muscle relaxation
.

  ① Body surface surgery; ② Limb surgery: laryngeal mask anesthesia combined with upper and lower extremity nerve blocks can be used; ③ Laparoscopic abdominal surgery: laparoscopic cholecystectomy/appendix/colectomy, laparoscopic gynecological surgery, laparoscopic nephrectomy, elective dissection Maternity surgery, elective open appendix/colon surgery,
etc.

 1.
Outpatient and minor surgery patients under general anesthesia
.

 2.
Short body surface and limb surgery in adults and children under general anesthesia
.

 3.
Patients who need to establish an artificial airway urgently
.

 4.
Patients who need airway protection and cannot be intubated
.

 5.
CT examination and airway management of interventional therapy for sedation or general anesthesia
.

 6.
Patients with unstable cervical spine general anesthesia
.

 7.
MRI examination of critically ill patients
.

 8.
Laparoscopic surgery
.

 9.
Eye surgery
.

  1.
Unable to place: extremely limited mouth opening 2.
Affects the operation of the surgical field 3.
High risk of aspiration: full stomach, acute intestinal obstruction, symptomatic gastroesophageal reflux, etc.
4.
Patients with decreased respiratory system compliance 5.
It is expected to require long-term Patients undergoing mechanical ventilation support 6.
Patients with upper airway reflexes: for example, in emergency, non-deep coma, patients with intact gag reflex 1, satiation, high intra-abdominal pressure, and high risk of vomiting, reflux and aspiration
.

2.
Patients with a history of habitual vomiting and reflux
.

3.
Patients with throat infection or other pathological changes
.

4.
Surgery that must maintain continuous positive pressure ventilation
.

5.
Patients with respiratory bleeding
.

6.
Patients with chronic respiratory diseases whose ventilation pressure needs to be greater than 25 cmH2O
.

7.
Patients with small mouth, large tongue or abnormally enlarged tonsils
.

 1.
Stomach full, intra-abdominal pressure is too high, there is a high risk of reflux aspiration
.

2.
There is infection or other pathological changes in the throat
.

3.
Respiratory bleeding
.

4.
The position of the laryngeal mask is difficult to maintain in the correct fixed position (prone position surgery, neck surgery)
.

5.
Thoracotomy
.

  Positive pressure ventilation for patients with full stomach and obesity, positive pressure ventilation for patients with chronic obstructive pulmonary disease (COPD), single-lung ventilation for thoracotomy, long-term neurosurgery, patients with high airway secretion,
etc.

 (1) Absolute contraindications 1.
Patients without fasting and delayed gastric emptying
.

 2.
There is a risk of reflux and aspiration: such as hiatal hernia, pregnancy, intestinal obstruction, acute abdomen, thoracic injury, patients with severe trauma and a history of reflux of gastric contents
.

3.
Airway obstruction that may occur after anesthesia in patients with tracheal compression and tracheomalacia
.

 4.
Obesity, oropharyngeal disease and COPD, pregnancy more than 14 weeks
.

 5.
The mouth opening is small and the laryngeal mask cannot pass
.

 (2) Relative contraindications 1.
Patients with low pulmonary compliance or high pulmonary resistance: such patients are usually ventilated with positive pressure (25-30 cmH2O), and air leakage around the ventilation mask and anesthetic gas entering the stomach often occur
.

 2.
Throat lesions: patients with throat abscesses, hematomas, edema, tissue damage and tumors
.

When laryngeal lesions may cause upper airway obstruction
.

 3.
The respiratory tract is not easily accessible or some special positions: such as prone, side lying and when the anesthesiologist is required to stay away from the operating table
.

Physicians cannot immediately perform endotracheal intubation and other management due to LMA displacement or prolapse and vomiting and regurgitation
.

In the next issue, the actual laryngeal mask insertion technique will be analyzed in the next issue.
The conventional problem of air leakage of the laryngeal mask is analyzed in the previous link.
A variety of laryngeal masks~The experience of Xiaowu school laryngeal masks (3) The laryngeal masks in those textbooks~