xử TRI TANG PACO2 , THỞ MÁY, ĐH Y DƯỢC TP HCM

bài giảng dành cho sinh viên y khoa, bác sĩ, sau đại học , ĐH Y DƯỢC TP HCM PaCO2 > 45 mmHg & pH < 7.35: Res acidosis (inadequate VA). Etiology: Central nervous system Neuromuscular disorders Chest wall abnormalities Airway diseases Parenchymal diseases

IMPROVE PaCO2

Bs Phùng Nguyễn Thế Nguyên

FACTORS AFFECT PaCO2

PaCO2

VCO2

(CO2 production)

VA = VE - VD

Equaton to change

- PaCO2 known x VE known= PaCO2 desired x VE desired

- PaCO2 known x VT known= PaCO2 desired x VT desired

- PaCO2 known x f known= PaCO2 desired x f desired

Res acidosis

- PaCO2 > 45 mmHg & pH < 7.35: Res acidosis

(inadequate VA).

- Etiology:

• Central nervous system

• Neuromuscular disorders

• Chest wall abnormalities

• Airway diseases

• Parenchymal diseases

Child with MV (PC)

- Set pressure to obtain targeted VT.

- Adjust rate

- Increase Ti if it is short

- 90 kg PC: ABG pH 7,31 PaCO2 59, IP 10 (vt 600 ml), PEEP 0, F 10;

PaCO2 desired 40 mHg.

- Vt desired = vt 59/ 40 = 600 x 59/40 = 885 ml.

- Cs = Vt/p (Pplateau – PEEP) = 600/10 = 60 ml/cmH20

- p desired = 885/60 = 14.75  15 cmH20

Resp alkalosis

- PaCO2 < 35 mmHg & pH > 7.35: Res acidosis

(inadequate VA).

- Etiology:

• Central nervous system: encepalitis, meningitis

• Parenchymal diseases

• Hypoxia with compensatory hyperventilation

• MV

• Anxiety

• Metabolic problem: sepsis, hepatic diseases

Child with MV (PC)

- Set pressure to obtain targeted VT.

- Adjust rate

- Increase Ti if it is short

- 90 kg PC: ABG pH 7,51 PaCO2 29, IP 20 (vt 900 ml), PEEP 0, F 12;

PaCO2 desired 40 mHg.

- Vt desired = vt 59/ 40 = 900 x 29/40 = 635 ml.

- Cs = Vt/p (Pplateau – PEEP) = 900/20 = 45 ml/cmH20

- p desired = 635/45 = 14  15 cmH20

Res alkalosis during spontaneuos efforts

- 25 year old, 80 kg, VC 12 breath/min, Vt 8 ml/kg

- RR real 16 breath/min, Ph 7,5 PaCO2 30 manage?

- Drcrease f? decrease Vt?

- SIMV

- PS

- Sedation: agitation, Work of breathing, dysynchrony

- Head trauma: may be can not corrected

Res acidosis & metabolic alkalosis

Protocol for implementation of

permissive hypercapnia

- Hypercapnia progressively in increments of 10 mmHg

to max 80 mmHg/day.

- If hypercapnia > 80 mmHg, progress more slowly.

Airway clearance during MV

- Suction catheter diameter:

• French = circumference of the tube = d x 3,1416.

• Diameter: ½ -2/3 ET diameter.

• Suction catheter (Fr) = 1,5 diameter of ET

- Suction pressure:

• Adult: (-) 100-120 (max 150 mmHg).

• Child: (-) 80 -100 (max 125 mmHg).

• Infant: (-) 60-100 (max 100 mmHg).

Instilling saline

- 3-5 ml normal or half saline.

- Risk: dislodging bacteria

- Does not thin secretions.

- Worse airway obstruction.

- Reduce oxygenation.

- Irritaion to the airways, so cough episodes and

bronchospam.

- Prudent: Selective and routine

Thank you!