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עמוד בית
Tue, 05.12.23

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September 2023
Ivan Gur MD MPH MHA, Ronen Zalts MD, Monia Azzam MD, Khetam Hussein MD, Ami Neuberger MD, Eyal Fuchs MD

Background: At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, many patients presented with acute hypoxemic respiratory failure, requiring ventilatory support. One treatment method was the addition of a reservoir mask to a high flow nasal cannula (HFNC) (dual oxygenation).

Objectives: To evaluate the clinical outcomes of combining reservoir mask on top of a high-flow nasal cannula.

Methods: A retrospective cohort of adult patients who were admitted due to COVID-19 during the first year of the pandemic to Rambam Health Care Campus. The primary endpoint was 30-day mortality. Secondary endpoints were incidence of invasive positive pressure ventilation initiation and admission to the intensive care unit (ICU). Patients who received positive pressure ventilation for reasons other than hypoxemic respiratory failure or who were transferred to another facility while still on HFNC were excluded.

Results: The final analysis included 333 patients; 166 were treated with dual oxygenation and 167 with HFNC only (controls). No significant differences in baseline characteristics were noted between the groups. The dual oxygenation group was slightly older (69.2 ± 14.8 years vs. 65.6 ± 15.5 years, P = 0.034). The 30-day mortality (24.1% vs. 36.5%, P = 0.013), rates of invasive positive pressure ventilation (47% vs. 59.3%, P = 0.024), and ICU admissions (41.6% vs. 52.7%, P = 0.042) were all significantly lower in the dual oxygenation group.

Conclusions: The addition of reservoir masks to HFNC may improve the oxygenation and overall prognosis in patients with severe hypoxemia due to COVID-19.

December 2020
Nader Abdel-Rahman MD and Gabriel Izbicki MD

For most passengers, even those with respiratory disease, air travel is safe and comfortable. Some travelers may experience hypoxia at sea level but may not need supplemental oxygen during air travel in a hypobaric hypoxic environment. For some individuals compensatory pulmonary mechanisms may be inadequate, causing profound hypoxia. In addition, venous thromboembolism/pulmonary emboli may occur, especially during long haul flights. With adequate screening, patients at risk can be identified, therapeutic solutions can be proposed for the flight, and most can travel can continue safely with supplemental oxygen and other preventive measures.

March 2018
Narin N. Carmel-Neiderman MD, Idan Goren MD, Yishay Wasserstrum MD, Tal Frenkel Rutenberg MD, Irina Barbarova MD, Avigal Rapoport MD, Dor Lotan MD, Erez Ramaty MD, Naama Peltz-Sinvani MD, Adi Brom MD, Michael Kogan MD, Yulia Panina MD, Maya Rosman MD, Carmel Friedrich MD, Irina Gringauz MD, Amir Dagan MD, Iris Kliers MD, Tomer Ziv-Baran PhD and Gad Segal MD

Background: Accurate pulse oximetry reading at hospital admission is of utmost importance, mainly for patients presenting with hypoxemia. Nevertheless, there is no accepted or evidence-based protocol for such structured measuring.

Objectives: To devise and assess a structured protocol intended to increase the accuracy of pulse oximetry measurement at hospital admission.

Methods: The authors performed a prospective comparison of protocol-based pulse-oximetry measurement with non-protocol based readings in consecutive patients at hospital admission. They also calculated the relative percentage of improvement for each patient (before and after protocol implementation) as a fraction of the change in peripheral capillary oxygen saturation (SpO2) from 100%.

Results: A total of 460 patients were recruited during a 6 month period. Implementation of a structured measurement protocol significantly changed saturation values. The SpO2 values of 24.7% of all study participants increased after protocol implementation (ranging from 1% to 21% increase in SpO2 values). Among hypoxemic patients (initial SpO2 < 90%), protocol implementation had a greater impact on final SpO2 measurements, increasing their median SpO2 readings by 4% (3–8% interquartile range; P < 0.05). Among this study population, 50% of the cohort improved by 17% of their overall potential and 25% improved by 50% of their overall improvement potential. As for patients presenting with hypoxemia, the median improvement was 31% of their overall SpO2 potential.

Conclusions: Structured, protocol based pulse-oximetry may improve measurement accuracy and reliability. The authors suggest that implementation of such protocols may improve the management of hypoxemic patients.

December 2014
Ronit Marcus MD, Eli Shiloah MD, Avi Mizrahi MD, Osnat Gerah-Yehoshua and Micha J. Rapoport MD
September 2013
A. Elizur, A. Maliar, I. Shpirer, A. E. Buchs, E. Shiloah and M. J. Rapoport
 Background: Obstructive sleep apnea has been shown to be associated with impaired glucose metabolism and overt diabetes mellitus. However, the effect of hypoxic episodes on nocturnal glucose regulation in non-diabetic patients is unknown.

Objectives: To investigate the effect of hypoxemia and nocturnal glucose homeosatsis in non-diabetic patients with sleep apnea.

Methods: Seven non-diabetic patients with moderate to severe sleep apnea were connected to a continuous glucose-monitoring sensor while undergoing overnight polysomnography. Mean SpO2 and percentage of time spent at SpO2 < 90% were recorded. The correlation between mean glucose levels, the difference between consecutive mean glucose measurements (glucose variability) and the corresponding oxygen saturation variables were determined in each patient during REM[1] and non-REM sleep.

Results: No consistent correlation was found for the individual patient between oxygen saturation variables and glucose levels during sleep. However, a lower mean SpO2 correlated with decreased glucose variability during sleep (r = 0.79, P = 0.034). This effect was primarily evident during REM sleep in patients with significant, compared to those with mild, oxygen desaturations during sleep (> 30% vs. < 10% of sleeping time spent with SpO2 < 90%) (P = 0.03).

Conclusions: Severe nocturnal hypoxemia in non-diabetic patients with moderate to severe sleep apnea might affect glucose regulation primarily during REM sleep.


[1] REM = rapid eye movement

November 1999
Mordechai R Kramer MD, Victor Krivoruk MD PhD, Joseph Lebzelter PhD, Mili Liani BSc and Gershon Fink MD
Background: Hypoxemia is a common complication of chronic obstructive pulmonary disease and a major factor in patients’ prognosis and quality of life. The response to exercise has been evaluated by various means but no standardization has been accepted.

Objectives: To suggest a simple outpatient technique for evaluating the response of arterial oxygen saturation to exercise for use as a marker of disease severity.

Patients and methods: Ninety-six patients with various degrees of COPD1 were divided into three groups: mild (forced expiratory volume in 1 sec >65%), moderate (FEV12 between 50 and 65%), and severe (FEV1 <50%). Using continuous oximeter recording we measured oxygen saturation during 15 steps of climbing, and quantified  oxygen desaturation by measuring the “desaturation area”, defined as the area under the curve of oxygen saturation from the beginning of exercise through the lowest desaturarion point and until after recovery to the baseline level of oxygen percent saturation. Desaturation was correlated to spirometry, lung gas volumes, blood gas analysis, and 6 min walking distance.

Results A good correlation was found between severity of COPD and baseline SaO23, lowest SaO2, recovery time, and desaturation area.  A negative correlation was found between desaturation area and FEV1 (r=-0.65), FEV1/forced vital capacity (r=-0.58), residual volume to total lung capacity (r=0.52), and diffusing lung capacity for carbon monoxide (r=-0.52). In stepwise multiple regression analysis only FEV1 correlated significantly to desaturation area.  A good correlation was noted between 6 min walking distance and desaturation area with the 15 steps technique (r=0.56).

Conclusions: In patients with severe COPD, arterial hypoxemia during exercise can be assessed by simple 15 steps oximetry. This method can serve both as a marker for disease severity and to determine the need for oxygen supplementation.


COPD = chronic obstructive pulmonary disease

FEV1 = forced expiratory volume in 1 sec

SaO2 = arterial oxygen saturation

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