Oxygen Therapy in Right Heart Failure

The Diagnosis and Treatment of Postoperative Right Heart Failure by Dr. med. Juliane Ende, PD Dr. med. habil. Manuel Wilbring, Dr. med. Georg Ende, and Prof. Dr. med. Thea Koch in issue 29–30/2022

We read the article by Juliane Ende et al. with great interest (1). The evidence-based clinical practice guideline on oxygen therapy in acute care (2), published in June 2021, was obviously not considered in the literature search for the CME article.

In Figure 2, the recommended pulse oximetry saturation (SpO₂) is ≥90% for oxygen administration and ventilation in acute right heart failure. This threshold is not supported by references. Reference 6 in the article is a retrospective analysis of 46 patients; no details about oxygen therapy are given there. Reference 8 is the clinical practice guideline for infarct related cardiogenic shock, which still recommends an arterial target saturation (SaO₂) of 94–98%.

Readers won’t be able to understand the abbreviation “GoR” (which is likely to mean the recommendation level), and the methods section does not explain what levels I and IIa mean.

We agree that oxygen saturation in critically ill patients should be measured arterially, since pulse oximetry yields unreliable results in shock.

In the largest randomized controlled trial of patients with acute coronary syndrome, 1% of study participants were in cardiogenic shock, and those with an SpO₂ measurement below 90% were excluded. In a subgroup analysis of patients with an SpO₂ reading of 90–94% administration of oxygen did not improve survival (3).

We think it is important to name an upper target range of oxygen saturation under oxygen administration in acute right heart failure too. The lacking utility of hyperoxemia (an SpO₂ reading above 96%) as a therapeutic objective under oxygen administration has been well confirmed.

In spontaneously breathing patients with a risk for hypercapnia the upper limit for target saturation under oxygen administration should be 92% (2). A risk for hypercapnia exists in more than 25% of inpatients. Older patients are affected more commonly.

The median patient age for cardiac surgery in Germany is 70 years (4).

DOI: 10.3238/arztebl.m2022.0374

Prof. Dr. med. Jens Gottlieb
Medizinische Hochschule Hannover
Klinik für Pneumologie OE 6870
Hannover

Prof. Dr. med. Thomas Fühner
Klinik für Pneumologie, Intensiv- und Schlafmedizin
Klinikum Siloah/KRH Klinikum Region Hannover
Hannover

Conflict of interest statement

Prof. Gottlieb has received institutional funding from the German Respiratory Society as the coordinator of the clinical practice guideline oxygen therapy in acute medical settings.

Prof. Fühner declares that no conflict of interest exists.

References

1. Ende J, Wilbring M, Ende G, Koch T: The diagnosis and treatment of postoperative right heart failure. Dtsch Arztebl Int 2022; 119: 514–24

2. Gottlieb J, Capetian P, Hamsen U, et al.: [German S3 Guideline—Oxygen therapy in the acute care of adult patients]. Pneumologie 2022; 76: 159–216

3. James SK, Erlinge D, Herlitz J, et al.: Effect of oxygen therapy on cardiovascular outcomes in relation to baseline oxygen saturation. JACC Cardiovasc Interv 2020; 13: 502–13

4. Beckmann A, Meyer R, Lewandowski J, Markewitz A, Gummert J: German Heart Surgery Report 2020: The annual updated registry of the German society for thoracic and cardiovascular surgery. Thorac Cardiovasc Surg 2021; 69: 294–307