Venturi Mask Adjuvant Oxygen Therapy in Severe Acute Ischemic Stroke

From May 2006 so you can see if your incompetent hospital did any followup or is doing testing on their own with this Venturi mask or nasal cannula. 

Venturi Mask Adjuvant Oxygen Therapy in Severe Acute Ischemic Stroke

Elley H. H. Chiu, MD; Chin-San Liu, MD, PhD; Teng-Yeow Tan, MD; et al Ku-Chou Chang, MD

Author Affiliations Article Information

Arch Neurol. 2006;63(5):741-744. doi:10.1001/archneur.63.5.741

Abstract

Background  The effect of oxygen therapy in acute ischemic stroke remains undetermined.
Objective  To investigate the feasibility of eubaric hyperoxia therapy by Venturi mask (VM) in a group of patients who experienced a severe acute ischemic stroke.
Design  Patients experiencing a first-ever large middle cerebral artery infarction were recruited within 48 hours after stroke. Patients were subdivided to undergo therapy with a VM with a fraction of inspired oxygen of 40% or with a nasal cannula. A large middle cerebral artery infarction was defined as a large low-attenuation area of more than one third of the middle cerebral artery territory on brain images. Stroke severity was evaluated by the National Institutes of Health Stroke Scale.
Results  Seventeen patients were enrolled in the VM group and 29 in the nasal cannula group. All the demographic and clinical characteristics were equally distributed initially. The mean initial National Institutes of Health Stroke Scale score was 20.5 and 18.9 in the VM and nasal cannula groups, respectively. Atrial fibrillation was found in 11 (65%) patients in the VM and 17 (59%) patients in the nasal cannula groups. The VM therapy was initiated within 13.7 (range, 3.0-41.5) hours after stroke and the duration was 132.9 (range, 48.0-168.5) hours. In-hospital mortality was 1 (6%) in the VM group and 7 (24%) in the nasal cannula group (P=.12). In the VM group, there were fewer incidences of fever (4 [24%] vs 15 [52%]; P=.06), pneumonia (1 [6%] vs 6 [21%]; P=.18), and respiratory failure (3 [18%] vs 8 [28%]; P=.45), but a higher incidence of bedsores (3 [18%] vs 2 [7%]; P=.29).
Conclusions  By using VM therapy with a fraction of inspired oxygen of 40%, there might be less mortality and comorbidities in treated patients who experienced a severe acute ischemic stroke. Further randomized confirmatory studies should explore the decreased mortality in patients who experience a severe acute ischemic stroke, especially in those with a large middle cerebral artery infarction who undergo VM therapy with a fraction of inspired oxygen of 40%.

After stroke, supplemental oxygen is advised if there is evidence of hypoxia. However, data are lacking to support general use of supplemental oxygen in patients who experience an acute ischemic stroke. Hyperbaric oxygen (HBO) therapy has been studied for decades in patients who experience an acute ischemic stroke. The potential benefit of HBO might include increased oxygen delivery, decreased cerebral edema, and decreased lipid peroxidation.¹ But the effectiveness of HBO therapy in humans is undetermined.²

Other than HBO therapy, eubaric (normobaric) hyperoxia treatment after acute stroke has been investigated recently. Eubaric hyperoxia treatment significantly increased penumbral PO₂ during ischemia and increased penumbral PO₂ during reperfusion.³ Experimental studies revealed that eubaric hyperoxia might protect the cerebral cortex⁴ and improve the neuropathological outcome.⁵ However, 1 atm of 100% oxygen for the first 24 hours was not recommended for nonhypoxic patients who experienced minor or moderate strokes.⁶

Compared with HBO therapy, eubaric hyperoxia can be applied with a Venturi mask (VM) (Figure 1), which is a simple and readily available device.⁷ The device delivered the most precise inspired oxygen fraction. Thus, we sought to investigate the feasibility and explore the therapeutic effects of eubaric hyperoxia by using a VM in a group of patients with a large middle cerebral artery (MCA) infarction, aiming to generate a hypothesis for future randomized trials.

Methods

This study involved 46 consecutive patients who experienced a first-ever severe ischemic stroke and were admitted within 48 hours after stroke onset at Changhua Christian Hospital between January 1, 2000, and July 31, 2001. Patients were subdivided into 2 groups: 17 received supplemental oxygen therapy by a VM with a fraction of inspired oxygen of 40% and 29 declined to participate in the program but agreed to participate as control subjects by using a nasal cannula, 2 L/min. The inclusion criteria were as follows: (1) first-ever ischemic stroke, (2) infarction in the MCA territory presenting less than 48 hours after onset, (3) National Institutes of Health Stroke Scale score of 12, (4) modified Rankin Scale score no less than 4, and (5) brain computed tomographic images suggesting that the infarction area was more than one third of the MCA territory. The exclusion criteria were as follows: (1) any known respiratory distress before registry period noted, such as obstructive pulmonary disease and obstructive sleep apnea; (2) rapidly improving neurological deficits; (3) brain images that did not reveal the infarction area was more than one third of the MCA territory; (4) medically unstable, due to previously known endocrinological dysfunctions, hematological abnormalities, autoimmune diseases, or malignancies; (5) pregnancy; (6) seizure at onset of stroke; (7) received thrombolytic therapy within 3 months; and (8) inability to obtain informed consent.

The oxygen devices would be changed or their use discontinued when the patients began ventilation; also, there was no need for supplemental oxygen, which was left at the discretion of the investigators. Stroke severity was assessed by the National Institutes of Health Stroke Scale.

There were no restrictions to concomitant treatments, such as an intravenous infusion of isotonic sodium chloride solution, hyperosmotic agents, and oral antiplatelet drugs. Patients who underwent craniectomy would not be included in this study. All fever episodes had been treated with empirical antibiotics.

Stroke subtypes were classified according to the Oxfordshire Community Stroke Project criteria.⁸ The specific factors at baseline were defined as in the Copenhagen Stroke Study.⁹ We compared the baseline characteristics and the outcomes, including survival and hospital length of stay (LOS) by Pearson χ² or Fisher exact test if applicable. All values were reported as median (range) or mean (standard deviation), and tests were 2-tailed and differences considered to be statistically significant at P<.05. Data were analyzed using a commercially available software program (SPSS version 10.0 for Windows; SPSS Inc, Chicago, Ill).

Results

Among 1013 consecutive patients who experienced a stroke and were admitted over a period of 18 months, 103 had a large MCA infarction. Only 46 of these patients with a large MCA infarction who had a first-ever ischemic stroke and were admitted within 48 hours after stroke onset were recruited into the analysis. The mean age of the patients was 79 years (median, 81 years; range, 49-93 years). Demographic characteristics are shown in Table 1. Atrial fibrillation (AF) was found in 28 (61%) of the 46 patients. There were no baseline differences between the 2 groups, except a slightly higher diastolic blood pressure in the nasal cannula group. The mean initial National Institutes of Health Stroke Scale score was 21 in the VM group and 18 in the nasal cannula group.

The VM therapy was initiated within 13.7 hours after stroke onset (median, 13 hours; range, 3.0-41.5 hours). The duration of VM use was 132.9 hours (median, 96 hours; range, 48.0-168.5 hours). All complications and vital status are shown in Table 2.

The mortality of the VM and nasal cannula groups was 1 (6%) and 7 (24%) (this percentage is different from the percentages totaled in the figure because of rounding) (P=.12) (Figure 2). One patient in the VM group died 4 days after stroke onset. Seven patients in the nasal cannula group died within 1 week after stroke.

The incidence of pneumonia was 1 (6%) in the VM group vs 6 (21%) in the nasal cannula group. There were fever episodes in 4 (24%) patients in the VM group and 15 (52%) patients in the nasal cannula group (P=.06). Asymptomatic petechial hemorrhages were seen in 2 patients in the VM group.

The overall LOS was 17 days (median, 13 days; range, 3-65 days): 17.2 days (median, 13 days; range, 4-58 days) in the VM group and 21.1 days (median, 13 days; range, 3-65 days) in the nasal cannula group. In patients with the total anterior circulation infarction subtype, the LOS was 17.9 days in the VM group vs 28.1 days in the nasal cannula group. Among the 11 patients with AF in the VM group, there was 1 death among those with the total anterior circulation infarction subtype and 0 deaths among those with the partial anterior circulation infarction subtype. Among the 17 patients with AF in the nasal cannula group, there were 5 deaths among those with the total anterior circulation infarction subtype and 1 death among those with the partial anterior circulation infarction subtype.

More at link. 

Expert Panel: Cap Oxygen Saturation at 96% for Acutely Ill Patients

This whole problem could have been prevented if a protocol had been written up rather that just guidelines. If you get this therapy post-stroke, ask what the protocol for it is. 

Expert Panel: Cap Oxygen Saturation at 96% for Acutely Ill Patients

Recommends special caution for stroke, MI patients

• by Ashley Lyles, Staff Writer, MedPage Today October 25, 2018

For acutely ill patients, oxygen saturation should not exceed 96%, an international panel recommended.
A multidisciplinary team of clinicians was brought together by The BMJ as part of the Rapid Recommendation initiative to focus on the most effective approach to oxygen therapy for patients with acute medical illness. The team used findings from an April 2018 systematic review in the Lancet. The review indicated that additional oxygen in inpatients with normal oxygen saturation led to increases in mortality. The group came to the following conclusions:
1. Strong recommendation for patients receiving oxygen therapy to have peripheral capillary oxygen saturation (SpO2) of ≤96%
2. Weak recommendation for not beginning oxygen therapy at 90%-92% saturation for patients with acute stroke or myocardial infarction (MI)
3. Strong recommendation for not beginning oxygen therapy ≥93% saturation for patients with acute stroke or MI
Oxygen therapy should be implemented carefully like other clinical interventions, noted Daniel Horner, BA, MBBS, MD, of Royal College of Emergency Medicine in London, and Ronan O'Driscoll, MD, of Salford Royal NHS Foundation Trust in Salford, England, in an accompanying editorial. Previous recommendations pointed to the 2008 British Thoracic Society guidelines of 94%-98% and the 2015 Thoracic Society of Australia and New Zealand guideline of 92%-96%, the editorialists noted.
Change is needed in when and how clinicians use oxygen, the review's corresponding author, Reed Siemieniuk, MD, PhD, of McMaster University in Hamilton, Ontario, told MedPage Today. "Right now, way too many patients receive oxygen when they shouldn't and often those who do need oxygen, receive too much," said Siemieniuk.
"Because of this, some patients die that wouldn't have otherwise. With very few exceptions, oxygen should only be given to patients with low oxygen saturations. Healthcare teams need to be careful not to give too much oxygen when it is prescribed," Siemieniuk continued.
The paper included a corresponding infographic, which serves as a decision-making resource that highlights the recommendations, the quality of the evidence on which they're based, and the benefits and harms of oxygen therapy.
The researchers highlighted that patients randomized to considerable quantities of supplemental oxygen therapy were more like to die (RR 1.21; 95% CI 1.03-1.43). "The increase in mortality was highest in the trials with the greatest increase in SpO₂; this suggests a dose-response relation and strengthens the inference that excessive oxygen is a cause of death," the study authors wrote.
The data for lower limits were based on patients who had enrolled in clinical trials with baseline SpO₂ >90%. The findings are more certain for patients with initially higher SpO₂ (>92%) because the majority of patients in the trials had a SpO₂ ≥ 92% at baseline.
For instance, the largest trial evaluated found that 240 stroke patients had an initial SpO₂ of 90%-93.9%. Another trial looked at 1062 MI patients with an initial SpO₂ ≤94%. Because these trials focused on MI and stroke patients, it is not clear whether or not these outcomes are applicable to other conditions.
For stroke and MI, the confidence intervals data concerning absolute effects showed that giving these patients additional oxygen did not contribute to an important mortality decrease. Moreover, for stroke patients, additional oxygen is unlikely to decrease disability, the investigators emphasized.
Supplemental oxygen therapy in patients with acute MI is unlikely to reduce chest pain, recurrent MI, or coronary revascularization intervention necessity, Siemieniuk's group reported.
Siemieniuk acknowledged the limitations of their work as it "does not tell us exactly when oxygen is helpful," Siemieniuk said. "The panel did not discuss patients receiving elective surgery or neonates -- our recommendations may or may not apply to these patients," Siemieniuk emphasized.
Future studies are needed to determine whether or not supplemental oxygen benefits patients that have a SpO2 <92% and presenting with a stroke or MI and to also decide whether or not supplemental oxygen is harmful for patients with other conditions marked by SpO₂ 85%-94%.
The need for further research "should not delay change that is already supported by a compelling body of evidence," the editorialists concluded.

Siemieniuk did not report any disclosures.

• Primary Source

  The BMJ

  Source Reference: Siemieniuk R, et al "Oxygen therapy for acutely ill medical patients: a clinical practice guideline" BMJ 2018; 363: k4169.

• Secondary Source

  The BMJ

  Source Reference: Horner D, O'Driscoll R "Oxygen therapy for medical patients" BMJ 2018; 363: k4436.

• Additional Source

  The Lancet

  Source Reference: Chu DK et al "Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy (IOTA): A systematic review and meta-analysis" Lancet 2018; 391(10131): 1693-1705.