Delayed but successful response to noninvasive ventilation in COPD patients with acute hypercapnic respiratory failure

Figures & data

Table 1 Patients’ characteristics according to the response to NIV

Characteristics	Overall population (n=155)	NIV failure (n=10; 6.5%)	NIV success (n=145; 93.5%)	P-value
Age (years)	68±12	69±10	68±12	0.70
Male, n (%)	114 (73.6%)	8 (80%)	106 (73%)	0.63
BMI (kg/m^2)	29.5 (23.8–38.7)	24.0 (18.0–29.1)	31.0 (24.0–39.1)	0.03
SOFA score	4.0 (3.0–5.0)	5.5 (3.0–6.0)	4.0 (3.0–5.0)	0.27
Charlson comorbidity score	3 (2–5)	4 (3–5)	3 (2–5)	0.37
SAPS 2	36±11	43±20	35±10	0.23
MRC dyspnea score	5 (4–5)	5 (4–5)	5 (4–5)	0.72
DNI order, n (%)	96 (62%)	5 (40%)	91 (63%)	0.18
Knaus index C, n (%)	51 (33%)	2 (20%)	49 (34%)	0.50
Knaus index D, n (%)	74 (48%)	6 (60%)	68 (47%)	0.52
Clinical frailty score	6 (5–7)	6 (5–7)	6 (5–7)	0.58
Heart rate (bpm)	104±21	107±20	103±21	0.62
Respiratory rate (bpm)	28±7	26±8	28±7	0.55
Encephalopathy score	3 (2–4)	4 (1–5)	3 (2–4)	0.24
Systolic blood pressure (mmHg)	137±26	119±24	139±26	0.03
Albumin (g/L)	29.7±5.6	26.3±5.6	30.0±5.5	0.08
Prealbumin (g/L)	0.15±0.07	0.12±0.04	0.15±0.07	0.07
Respiratory depressant drugs, n (%)	31 (20)	1 (10)	30 (21)	0.68
Pneumonia, n (%)	57 (37)	5 (50)	52 (36)	0.50
Congestive heart failure, n (%)	22 (14)	1 (10)	21 (14.5)	1.00
Idiopathic, n (%)	68 (44)	3 (30)	65 (45)	0.51
Sepsis, n (%)	3 (2)	1 (10)	2 (1.4)	0.18
Pulmonary embolism, n (%)	3 (2)	0 (0)	3 (2.1)	1.00
Others, n (%)	2 (1)	0 (0)	2 (1.4)	1.00
pH	7.25 (7.19–7.32)	7.20 (7.14–7.33)	7.26 (7.20–7.32)	0.42
PaCO2 (mmHg)	76 (62–90)	76 (62–86)	76 (62–90)	0.83
PaO2/FiO2	227±74	255±83	226±74	0.30
FiO2 (%)	30 (25–45)	30 (25–45)	30 (25–40)	0.87
${\text{HCO}}_3^{-}\left(\text{mmol/L}\right)$	33.2±6.8	31.7±5.4	33.3±7.0	0.40
EPAP (cmH2O)	8 (6–8)	8 (6–8)	8 (6–8)	0.92
IPAP (cmH2O)	18 (16–18)	18 (17–20)	18 (16–18)	0.32
Inhospital mortality, n (%)	25 (16%)	5 (50%)	20 (14%)	0.01
LOS in hospital	13 (8–17)	11.5 (1–19)	13 (9–17)	0.42

Note: Data presented as mean ± SD or median (interquartile range, 25–75).

Abbreviations: BMI, body mass index; bpm, beat/breath per minute; DNI, do-not-intubate; EPAP, expiratory positive airway pressure; IPAP, inspiratory positive airway pressure; LOS, length of stay; MRC, Medical Research Council; NIV, noninvasive ventilation; SAPS 2, simplified acute physiologic score 2; SOFA, sequential organ failure assessment score.

Table 2 Comparison of the early responders with the delayed responders to NIV

Parameters	Early responders (n=62) (%)	Delayed responders (n=83) (%)	P-value
Age (years)	70±11	66±13	0.03
Male, n (%)	47 (76)	59 (71)	0.40
BMI (kg/m^2)	32.7 (23–38)	29.5 (24–40)	0.68
SOFA score	4 (3–4)	4 (3–5)	0.21
SAPS 2	34±9.6	36±9.8	0.30
Charlson comorbidity score	4 (3–5)	3 (2–4)	0.09
MRC dyspnea score	5 (4–5)	5 (4–5)	0.53
DNI order, n (%)	43 (69)	49 (59)	0.20
Knaus index C, n (%)	19 (30)	30 (36)	0.48
Knaus index D, n (%)	34 (55)	34 (41)	0.10
Clinical frailty score	7 (5–7)	6 (4–7)	0.12
Heart rate (bpm)	105±20	102±22	0.30
Respiratory rate (bpm)	29±6	27±7	0.15
Encephalopathy score	3 (2–4)	3 (2–4)	0.015
Systolic blood pressure (mmHg)	140±25	137±27	0.49
Albumin (g/L)	29.7±6	30.1±5	0.70
Prealbumin (g/L)	0.16±0.06	0.14±0.07	0.31
Respiratory depressant drugs, n (%)	9 (14.5)	21 (25.3)	0.11
Causes of AHRF, n (%)
Pneumonia	22 (35.5)	30 (36)	0.93
Congestive heart failure	11 (17.7)	10 (12)	0.33
Idiopathic	25 (40)	40 (48)	0.35
Sepsis	1 (1.6)	1 (1.2)	0.83
Pulmonary embolism	2 (3.2)	1 (1.2)	0.58
Other	1 (1.6)	1 (1.2)	1.00
pH	7.27 (7.23–7.33)	7.25 (7.19–7.33)	0.17
PaCO2 (mmHg)	73 (61–82)	80 (62–91)	0.06
PaO2/FiO2	222±70	229±76	0.57
FiO2 (%)	30 (25–45)	30 (25–40)	0.51
${\text{HCO}}_3^{-}\left(\text{mmol/L}\right)$	33±7	33.5±6	0.73
EPAP (cmH2O)	7.5 (6–8)	8 (6–8)	0.04
IPAP (cmH2O)	17 (16–18)	18 (16–19)	0.24
Outcome, n (%)
Late NIV failure	9 (14.5)	11 (13.2)	0.83
Inhospital death	10 (16%)	10 (12%)	0.49

Note: Data presented as mean ± SD or median (interquartile range, 25–75).

Abbreviations: AHRF, acute hypercapnic respiratory failure; BMI, body mass index; bpm, beat/breath per minute; DNI, do-not-intubate; EPAP, expiratory positive airway pressure; IPAP, inspiratory positive airway pressure; MRC, medical research council; NIV, noninvasive ventilation; SAPS 2, simplified acute physiologic score 2; SOFA, sequential organ failure assessment score.

Figure 1 Flowchart of the distribution of patients according to the response to NIV.

Note: H0, at NIV initiation; H2, after 2 h of NIV trial; and H48, after 48 h of NIV.
Abbreviations: AHRF, acute hypercapnic respiratory failure; DNI, do-not-intubate; NIV, noninvasive ventilation.

Table S1 Clinical frailty score

Score	Frailty grade	Description
1	Very fit	People who are robust, active, energetic, and motivated. These people commonly exercise regularly. They are among the fittest for their age
2	Well	People who have no active disease symptoms but are less fit than those of category 1. Often, they exercise or are very active occasionally (that is, seasonally)
3	Managing well	People whose medical problems are well controlled, but are not regularly active beyond routine walking
4	Vulnerable	While not dependent on other for daily help, symptoms often limit activities. A common complaint is being slowed up, and/or being tired during the day
5	Mildly frail	These people often have more evident slowing, and need help in high-order independent activities of daily living (finances, transportation, heavy housework, medications). Typically, mild frailty progressively impairs shopping and walking outside alone, meal preparation, and housework
6	Moderately frail	People need help with all outside activities and with keeping house. Inside, they often have problems with stairs and need help with bathing and might need minimal assistance (cuing, standby) with dressing
7	Severely frail	Completely dependent for personal care, from whatever cause (physical or cognitive). Even so, they seem stable and not at high risk of dying (within ~6 months)
8	Very severely frail	Completely dependent, approaching the end of life. Typically, they could not recover even from a minor illness.
9	Terminally ill	Approaching the end of life. This category applied to people with a life expectancy <6 months, who are not otherwise evidently frail

Note: Adapted from McDermid RC, Stelfox HT, Bagshaw SM. Frailty in the critically ill: a novel concept. Crit Care. 2011;15(1):301.⁴

McDermidRCStelfoxHTBagshawSMFrailty in the critically ill: a novel conceptCrit Care201115130121345259

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