Effects of normobaric hyperoxia on haemodynamic parameters of healthy full‐term parturients

Litchfield, K.; Harten, J.; Anderson, Keith; Kinsella, John; McGrady, Elizabeth

doi:10.1111/j.1365-2044.2007.05150.x

Cited by 7 publications

(8 citation statements)

References 43 publications

(54 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The use of short-term hyperoxia poses no health risks to the mother or fetus. There is no significant change in maternal heart rate or mean arterial pressure (15,16) in the otherwise healthy mother owing to existing highly saturated hemoglobin. In the fetus, hyperoxia increases fetal movements (17) but does not change brain oxygenation, which is suggestive of a reversed brain-sparing mechanism (12).…”

Section: Methodsmentioning

confidence: 94%

MR Imaging Measurements of Altered Placental Oxygenation in Pregnancies Complicated by Fetal Growth Restriction

et al. 2017

View full text Add to dashboard Cite

Purpose To evaluate oxygen-enhanced and blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging parameters in normal pregnancies and those complicated by fetal growth restriction (FGR). Materials and Methods This case-control study was approved by the local research ethics committee. Informed consent was obtained from all subjects. From October 2010 to October 2015, 28 women with uncomplicated pregnancies (individualized birthweight ratio [IBR] >20th percentile and delivery >37 weeks) and 23 with pregnancies complicated by FGR (IBR <5th percentile and abnormal Doppler ultrasonography [US] studies) underwent MR imaging. Differences in placental longitudinal R1 (1/T1) and transverse R2* (1/T2*) were quantified, with subjects breathing either air or oxygen. The difference in R1 (ΔR1) after hyperoxia was converted to change in partial pressure of oxygen (ΔPo). Data were acquired prospectively, with retrospective interpretation of group differences (unpaired t tests). Diagnostic models were developed by using logistic regression analysis with gestational age as a covariate. Results The mean baseline R1 and R2* for normal pregnancies (R1: 0.59 sec, 95% confidence interval [CI]: 0.58 sec, 0.60 sec; R2*: 17 sec, 95% CI: 14 sec, 20 sec) were significantly different from those of pregnancies complicated by FGR (R1: 0.63 sec, 95% CI: 0.62 sec, 0.65 sec; R2*: 26 sec, 95% CI: 22 sec, 32 sec) (P < .0001). The ΔR1 showed a significant negative association with gestational age (P < .0001) in the combined cohort, with the FGR group having a ΔR1 that was generally 61.5% lower than that in the normal pregnancy group (P = .003). The area under the receiver operating characteristic curve for the differentiation between pregnancy complicated by FGR and normal pregnancy by using ΔPo, baseline R1, and baseline R2* was 0.91 (95% CI: 0.82, 0.99). Conclusion R1, R2*, and ΔPo were significantly different between normal pregnancies and those complicated by severe FGR. MR imaging parameters have the potential to help identify placental dysfunction associated with FGR and may have clinical utility in correctly identifying FGR among fetuses that are small for gestational age. A larger prospective study is needed to assess the incremental benefit beyond that offered by US. RSNA, 2017.

show abstract

Section: Methodsmentioning

confidence: 94%

MR Imaging Measurements of Altered Placental Oxygenation in Pregnancies Complicated by Fetal Growth Restriction

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In the present study, the values obtained while breathing medical air through the mask were used as a control for breathing 100% oxygen. Such a design has been used in other studies [ 12 , 20 , 44 ].…”

Section: Discussionmentioning

confidence: 99%

The effect of hyperoxia on central blood pressure in healthy subjects

Siński

Lewandowski

Dobosiewicz

et al. 2016

aoms

View full text Add to dashboard Cite

IntroductionHyperoxia increases total peripheral resistance by acting locally but also inhibits the activity of carotid body chemoreceptors. We studied the effect of hyperoxia on central pressure in normotensive subjects.Material and methodsMedical air followed by 100% oxygen was provided to 19 subjects (12/7 female/male, age 28.2 ±1.1 years) for 15 min through a non-rebreather mask. Central blood pressure was then measured using applanation tonometry.ResultsAfter the first 2 min of hyperoxia, heart rate decreased significantly (65 ±2.6 beats/min vs. 61 ±2.1 beats/min, p = 0.0002). Peripheral and central blood pressure remained unchanged, while hemoglobin oxygen saturation and subendocardial viability ratio index increased (97 ±0.4% vs. 99 ±0.2%, p = 0.03; 168 ±8.4% vs. 180 ±8.2%, p = 0.009). After 15 min of 100% oxygen ventilation, heart rate and peripheral and central blood pressures remained unchanged from the first 2 min. The augmentation index, augmentation pressure and ejection duration increased as compared to baseline values and those obtained at 2 min (–5.1 ±2.9% vs. –1.2 ±2.6%, p = 0.005 and –4.6 ±2.7% vs. –1.2 ±2.6%, p = 0.0015; –1.3 ±0.7 mm Hg vs. –0.2 ±1.2 mm Hg, p = 0.003 and –1.1 ±0.7 mm Hg vs. –0.2 ±1.2 mm Hg, p = 0.012; 323 ±3.6 ms vs. 330 ±3.5 ms, p = 0.0002 and 326 ±3.5 ms vs. 330 ±3.5 ms, p = 0.021, respectively).ConclusionsThe present study shows that hyperoxia does not affect central blood pressure in young healthy subjects and may improve myocardial blood supply estimated indirectly from applanation tonometry.

show abstract

“…From previous data we had calculated that our study was adequately powered to detect a difference in CI of 0.4 l min À1 m À2 [26][27][28]. One source of error, however, is that ephedrine has both direct and indirect beta agonist properties, which could therefore affect both CI and SVRI.…”

Section: Discussionmentioning

confidence: 99%

Randomised controlled trial of combined spinal epidural vs. spinal anaesthesia for elective caesarean section: vasopressor requirements and cardiovascular changes

Macfarlane

Pryn

Litchfield

et al. 2009

European Journal of Anaesthesiology

View full text Add to dashboard Cite

show abstract

Effects of normobaric hyperoxia on haemodynamic parameters of healthy full‐term parturients

Cited by 7 publications

References 43 publications

MR Imaging Measurements of Altered Placental Oxygenation in Pregnancies Complicated by Fetal Growth Restriction

MR Imaging Measurements of Altered Placental Oxygenation in Pregnancies Complicated by Fetal Growth Restriction

The effect of hyperoxia on central blood pressure in healthy subjects

Randomised controlled trial of combined spinal epidural vs. spinal anaesthesia for elective caesarean section: vasopressor requirements and cardiovascular changes

Contact Info

Product

Resources

About