A nationwide structure for valid long-term oxygen therapy: 29-year prospective data in Sweden

Figures & data

Table 1 The national structure of LTOT in Sweden

Assessments (N responding units)	Units (%)
A physician is responsible for LTOT management (n=42)	31 (74)
A diagnosis is set by a physician before prescribing LTOT (n=41)	39 (95)
The health intervention code AG062 is registered to a physician’s appointment or inpatient occasion when starting LTOT (n=41):
Always	5 (12)
Sometimes	8 (20)
Never or don’t know what it’s about	28 (68)
Full-time employments (40 hours/week) allocated to oxygen personnel (registered nurses, assistant nurses, or physiotherapists)	15 (37)
Oxygen personnel (nurses or physiotherapists) working at the outpatient clinic with LTOT patients:
5 days/week	26 (60)
3–4 days/week	9 (21)
The oxygen service is provided within the following organization:
Respiratory clinic	28 (65)
Internal medicine clinic	6 (14)
Independent clinic	1 (2)
Other organization	8 (18)
Organization of personnel, ie, if nurses, physiotherapists, technicians work entirely with oxygen or with other services as well:
Entirely with oxygen therapy	8 (18)
Shared with CPAP or home ventilation	9 (20)
Shared with allergy clinic	10 (23)
Together with lung clinic	25 (57)
Other service	14 (32)
Oxygen courses attended by some of the personnel:
Oxygen course arranged by Swedevox	24 (55)
AGA	25 (57)
AIOLOS	20 (45)
Philips Respironics	19 (43)
Other course	9 (20)
Work experience with LTOT patients of the most experienced oxygen nurse:
Less than 1 year	0
Less than 5 years	11 (26)
More than 5 years	32 (74)
Home visits carried out in LTOT patients:
Routinely	30 (70)
In selected cases	6 (14)
No home visits	7 (16)
Reevaluation within 3 months of LTOT start:
Routine reevaluation	9 (20)
Routine reevaluation of LTOT started after exacerbation	10 (23)
Sometimes	7 (17)
No	17 (40)
The oxygen equipment and information about LTOT if provided to patients at home by:
Oxygen nurses	33 (77)
Technicians	8 (18)
Other personnel	2 (5)
Use of checklists as help at the initiation of LTOT	36 (83)
A separate list of the patients prescribed LTOT is kept, in addition to the Swedevox registration	42 (98)
Patients sign a non-smoking agreement before starting LTOT	23 (53)
Smoking is assessed after start of LTOT (COHb/urine):
Yes, routinely	4 (9)
Yes, but only when smoking is suspected	9 (20)
No	30 (70)
A cognitive assessment (eg, MMT) is performed before LTOT startup	5 (12)
Time dedicated for registration in Swedevox	14 (33)
Patients are registered in Swedevox within (n=42):
A week of LTOT start	18 (43)
A month of LTOT start	13 (31)
When prescribing LTOT, the evaluation is normally done at:
Inpatient on the ward	40 (92)
Outpatient clinic	29 (66)
The patient’s home	3 (7)
Other	1 (2)
In patients with CO2 retention (PaCO2>.6.5 kPa), LTOT is evaluated in hospital (n=38)	32 (84)
A routine walk test is carried out with the prescribed oxygen dose before LTOT is prescribed:
Yes always, patients walk for 6 minutes	5 (12)
Yes, patient walk 500 meters	8 (18)
Sometimes	15 (35)
No	15 (35)
Feedback received from data in Swedevox to the LTOT clinic, eg, annually (n=41)	21 (51)

Notes: The structure of LTOT services was assessed in 2014 through a web-based questionnaire to all units prescribing LTOT in Sweden. The coverage for the questionnaire was 90% (43 out of 48 clinics answered the questionnaire).

Abbreviations: CoHb, carboxyhemoglobin; LTOT, long-term oxygen therapy; MMT, Mini Mental Test; PaCO₂, partial pressure of arterial carbon dioxide.

Figure 1 Primary physician-diagnosed cause for starting LTOT.

Notes: Reasons for starting LTOT: airways disease, parenchymal disease, pulmonary vascular disease, and other. Airways disease was the main underlying cause for prescribing LTOT (69%).
Abbreviation: LTOT, long-term oxygen therapy.

Table 2 Quality of LTOT in Sweden in 2015

Quality criteria	Aim, % of patients	Percentage of patients fulfilling criteria in 2015
PaO2 (air) <7.4 kPa	>85	88
PaO2 (oxygen) ≥8.0 kPa	<90	75
Current smokers	<5	2
Patients with thoracic deformity on	0	0
LTOT but without concomitant home mechanical ventilation
Mobile oxygen to ambulatory patients*	>50	76
LTOT prescribed ≥16 hours/day	>95	98
Reevaluation of hypoxemia if	>70	60
LTOT was started in relation to an exacerbation in 2014
Maintenance treatment with oral glucocorticoids in people with COPD	<20	15

Note:

* Assessed at follow-up after 1 year among patients starting LTOT in 2014.

Abbreviations: LTOT, long-term oxygen therapy; PaO₂ (air), arterial blood gas tension of oxygen on air; SD, standard deviation; PaO₂ (oxygen), arterial blood gas tension of oxygen on oxygen.

Figure 2 Mean PaO₂ on room air (±2 SD) (A) and mean PaO₂ on oxygen (±2 SD) (B).

Notes: The mean PaO₂ breathing ambient air before LTOT start was stable during the study period at 6.5 (SD, 0.9) kPa. The mean PaO₂ on oxygen was stable during the study period at 8.6 (SD, 1.2) kPa.
Abbreviations: PaO₂ (air), arterial blood gas tension of oxygen on air; SD, standard deviation; PaO₂ (oxygen), arterial blood gas tension of oxygen on oxygen; LTOT, long-term oxygen therapy.

Figure 3 Percentage fulfilling criteria for LTOT prescription, oxygen delivery mode, and reevaluation of treatment (A) and percentage fulfilling quality criteria for LTOT (B).

Notes: The criteria in (A) pertain to the percentage of LTOT patients with prescribed daily LTOT duration above 16 hours/day; portable oxygen at 1-year follow-up, and reevaluation of hypoxemia when LTOT was started in relation to an exacerbation. Oxygen was prescribed for 15 hours/day or more in 98% of patients; prescription of mobile oxygen to ambulatory patients varied during the study period but the aim of >50% was fulfilled; and an increase in reevaluation of oxygen treatment if started in relation to an exacerbation was seen during the study period. The criteria in (B) pertain to the percentage of LTOT patients being non-smokers and the absence of maintenance treatment with oral corticosteroids. The rate of non-smokers was stable at 98% during the study period, in accordance with the quality criteria. Maintenance treatment with oral glucocorticoids was low during the study period.
Abbreviation: LTOT, long-term oxygen therapy.

Figure S1 English translation of the web-based questionnaire from 2014.

Note: Intervention code AG062: this is a health code that refers to start of oxygen treatment.

Abbreviations: LTOT, long-term oxygen therapy; PaCO₂, partial pressure of arterial carbon dioxide.

Table S1 Variables in Swedevox registry

Variable	Definition
Birth date	Birth date from the Swedish Population Register
Sex	Sex from the Swedish Population Register
Primary and secondary causes of LTOT	Main and contributing physician-diagnosed cause(s) of starting LTOT
Follow-up, years	Follow-up after starting LTOT
Stop date and stop cause	Date and reason for discontinuing LTOT
PaO2 air, kPa	Arterial blood gas tension of oxygen on air
PaCO2 air, kPa	Arterial blood gas tension of carbon dioxide on air
PaO2 oxygen, kPa	Arterial blood gas tension of oxygen on oxygen
PaCO2 oxygen, kPa	Arterial blood gas tension of carbon dioxide on oxygen
FEV1, L	Forced expiratory volume in 1 second
FEV1, % of predicted	Forced expiratory volume in 1 second as percentage of predicted value
VC, L	Vital capacity (the highest value of the slow and forced vital capacity)
WHO status, n (%)	World Health Organization Performance Status
Height (cm) and weight (kg)	Height and weight
Never smoker, %	Smoking status
Past smoker, %	Smoking status
Current smoker, %	Smoking status
Maintenance treatment with oral corticosteroids, %	Long-term treatment with corticosteroids
Oxygen dose, L/minute	Prescribed oxygen dose
Oxygen duration, hour/24 hours	Prescribed oxygen duration

Abbreviations: FEV₁, forced expiratory volume in 1 second; LTOT, long-term oxygen therapy; PaO₂ (air), arterial blood gas tension of oxygen on air; SD, standard deviation; PaO₂ (oxygen), arterial blood gas tension of oxygen on oxygen; PaCO₂, partial pressure of arterial carbon dioxide; VC, vital capacity; WHO, World Health Organization.