Risk Factors of Thomas et al for Prolonged Intubation in a Patient with Myasthenic Crisis

 

Myasthenic crisis is neuromuscular respiratory failure requiring mechanical ventilation.

 

Independent predictors of prolonged intubation:

(1) pre-intubation serum bicarbonate concentration

(2) peak vital capacity (VC) on day 1 to day 6 after intubation

(3) age in years

Parameter	Finding	Points
age of the patient in years	<= 50 years	0
	> 50 years	1
peak vital capacity on day 1 to day 6 after intubation	>= 25 mL per kg	0
	< 25 mL per kg	1
pre-intubation serum bicarbonate	< 30 mmol/L	0
	>= 30 mmol/L	1

 

where:

• The paper references serum bicarbonate as 30 mg/dL but the units should be mmol/L or mEq/L.

 

number of predictors =

= SUM(points for all 3 predictors)

 

Interpretation:

• minimum number of predictors: 0

• maximum number of predictors: 3

• The greater the number of predictors the longer the intubation required.

 

Number of Predictors	Intubation > 2 Weeks
0	0%
1	21%
2	46%
3	88%

 

Complications during the hospitalization which may prolong the period of intubation:

(1) atelectasis (also associated with weaning failure, see previous section)

(2) anemia requiring transfusion

(3) Clostridium difficile disease

(4) congestive heart failure (CHF)