scholarly journals Hypoxaemia following Sustained Low-Volume Venous Air Embolism in Sheep

1988 ◽  
Vol 16 (2) ◽  
pp. 164-170 ◽  
Author(s):  
J. Pfitzner ◽  
S. P. Petito ◽  
A. G. McLean
Keyword(s):  
Arterial Oxygen Saturation ◽  
Air Embolism ◽  
Arterial Oxygen ◽  
Venous Air Embolism ◽  
Minute Period ◽  
Volume Ventilation ◽  
Gas Measurements ◽  
Respiratory Disturbance ◽  
Upright Head ◽  
End Tidal

In six upright (head above thorax) anaesthetised sheep, serial blood gas measurements were made over a 100-minute period during which repeated small-volume air emboli were injected intravenously to lower and maintain the end-tidal CO 2 concentration approximately 0.5% below its initial baseline level. With constant volume ventilation and an inspired N 2 O:O 2 ratio of 2:1, the arterial PCO 2 progressively increased and the arterial PO 2 progressively decreased with significant arterial hypoxaemia ensuing in three out of the six animals. It is suggested that during neurosurgery performed in the sitting position and with an inspired oxygen concentration of 33%, the degree of cardio-respiratory disturbance caused by venous air embolism should be assessed by continuous monitoring not only of end-tidal CO 2 concentration but also of arterial oxygen saturation using pulse oximetry.

Obstructive Sleep Apnea in Children With Down Syndrome

PEDIATRICS ◽  
1991 ◽  
Vol 88 (1) ◽  
pp. 132-139
Author(s):  
Carole L. Marcus ◽  
Thomas G. Keens ◽  
Daisy B. Bautista ◽  
Walter S. von Pechmann ◽  
Sally L. Davidson Ward
Keyword(s):  
Obstructive Sleep Apnea ◽  
Down Syndrome ◽  
Sleep Apnea ◽  
Arterial Oxygen Saturation ◽  
Sleep Apnea Syndrome ◽  
Arterial Oxygen ◽  
Children With Down Syndrome ◽  
Obstructive Sleep ◽  
Apnea Syndrome ◽  
End Tidal

Children with Down syndrome have many predisposing factors for the obstructive sleep apnea syndrome (OSAS), yet the type and severity of OSAS in this population has not been characterized. Fifty-three subjects with Down syndrome (mean age 7.4 ± 1.2 [SE] years; range 2 weeks to 51 years) were studied. Chest wall movement, heart rate, electrooculogram, end-tidal Po2 and Pco2, transcutaneous Po2 and Pco2, and arterial oxygen saturation were measured during a daytime nap polysomnogram. Sixteen of these children also underwent overnight polysomnography. Nap polysomnograms were abnormal in 77% of children; 45% had obstructive sleep apnea (OSA), 4% had central apnea, and 6% had mixed apneas; 66% had hypoventilation (end-tidal Pco2, >45 mm Hg) and 32% desaturation (arterial oxygen saturation <90%). Overnight studies were abnormal in 100% of children, with OSA in 63%, hypoventilation in 81%, and desaturation in 56%. Nap studies significantly underestimated the presence of abnormalities when compared to overnight polysomnograms. Seventeen (32%) of the children were referred for testing because OSAS was clinically suspected, but there was no clinical suspicion of OSAS in 36 (68%) children. Neither age, obesity, nor the presence of congenital heart disease affected the incidence of OSA, desaturation, or hypoventilation. Polysomnograms improved in all 8 children who underwent tonsilletomy and adenoidectomy, but they normalized in only 3. It is concluded that children with Down syndrome frequently have OSAS, with OSA, hypoxemia, and hypoventilation. Obstructive sleep apnea syndrome is seen frequently in those children in whom it is not clinically suspected. It is speculated that OSAS may contribute to the unexplained pulmonary hypertension seen in children with Down syndrome.

Relationship of ovarian hormones to hypoxemia in women residents of 4,300 m

2001 ◽  
Vol 280 (2) ◽  
pp. R488-R493 ◽  
Author(s):  
F. León-Velarde ◽  
M. Rivera-Chira ◽  
R. Tapia ◽  
L. Huicho ◽  
C. Monge-C
Keyword(s):  
Luteal Phase ◽  
Arterial Oxygen Saturation ◽  
Premenopausal Women ◽  
Arterial Oxygen ◽  
Chronic Mountain Sickness ◽  
Physiological Variables ◽  
Cerro De Pasco ◽  
End Tidal ◽  
Hb Concentration ◽  
Relationship Of

Prevalence of excessive erythrocytosis, the main sign of chronic mountain sickness (CMS), is greater in postmenopausal Andean women than in premenopausal women. It is uncertain whether this greater prevalence is related to the decline in female hormones and ventilatory function after the occurrence of the menopause. To study this, we compared the physiological variables involved in the physiopathology of CMS [end-tidal CO2 (Pet CO2 , Torr) and end-tidal O2 (Pet O2 , Torr), arterial oxygen saturation (SaO2 , %), and Hb concentration (g/dl)] and progesterone and estradiol levels between postmenopausal and premenopausal women, both in the luteal and follicular phases. Women residing in Cerro de Pasco ( n= 33; 4,300 m) aged 26–62 yr were studied. Postmenopausal women compared with premenopausal women in the luteal phase had lower Pet O2 (48 ± 4 vs. 53 ± 2 Torr, P = 0.005) and SaO2 levels (82 ± 12 vs. 88 ± 12%, P < 0.005) and higher Pet CO2 (34 ± 2 vs. 29 ± 3 Torr, P = 0.005) and Hb concentration (19 ± 1 vs. 14 ± 2 g/dl, P < 0.005). In addition, plasma progesterone was negatively correlated with Pet CO2 and positively correlated with Pet O2 and SaO2 . No clear relationship was found among the cycle phases between estradiol and the variables studied. In conclusion, our results reveal that, before menopause, there is better oxygenation and lower Hb levels in women long residing at altitude, and this is associated with higher levels of progesterone in the luteal phase of the cycle.

Venous Air Embolism, Hypotension, and End-Tidal Nitrogen

Neurosurgery ◽  
1987 ◽  
Vol 21 (3) ◽  
pp. 378-382 ◽  
Author(s):  
Jane M. Matjasko ◽  
Jeffrey Hellman ◽  
Colin F. Mackenzie
Keyword(s):  
Air Embolism ◽  
Venous Air Embolism ◽  
End Tidal

Venous Air Embolism during Endoscopic Strip Craniectomy for Repair of Craniosynostosis in Infants

2001 ◽  
Vol 95 (2) ◽  
pp. 340-342 ◽  
Author(s):  
Joseph D. Tobias ◽  
Joel O. Johnson ◽  
David F. Jimenez ◽  
Constance M. Barone ◽  
D. Scott McBride
Keyword(s):  
Surgical Procedures ◽  
Operating Time ◽  
Air Embolism ◽  
Postoperative Recovery ◽  
Surgical Time ◽  
Venous Air Embolism ◽  
Low Incidence ◽  
End Tidal ◽  
Neonates And Infants ◽  
Strip Craniectomy

Background Various studies have reported an incidence of venous air embolism (VAE) as high as 82.6% during surgical procedures for craniosynostosis. There has been an increase in the use of minimally invasive, endoseopie surgical procedures, including applications for endoscopic strip craniectomy. The current study prospectively evaluated the incidence of VAF during endoscopic strip craniectomy. Methods Continuous, intraoperative monitoring for VAE was performed using precordial Doppler monitoring. A recording was made of the Doppler tones and later reviewed to verify its accuracy. Results The cohort for the study included 50 consecutive neonates and infants ranging in age from 3.5 to 36 weeks and ranging in weight from 3 to 9 kg. Surgical time varied from 31 to 95 min for a total of 2,701 mm of operating time, during which precordial Doppler tones were auscultated. In 46 patients, there was no evidence of VAE. In four patients, there was a single episode of VAE. Two of the episodes of VAE were grade I (change in Doppler tones), and two were grade H (change in Doppler tones and decrease in end-tidal carbon dioxide). No grade III (decrease in systolic blood pressure by 20% from baseline) VAF was noted. Conclusion In addition to previously reported benefits of decreased blood loss, decreased surgical time, and improved postoperative recovery time, the authors noted a low incidence of VAF during endoscopic strip craniectomy in neonates and infants.

Sensitivity of End-tidal Nitrogen in Venous Air Embolism Detection in Dogs

1985 ◽  
Vol 63 (4) ◽  
pp. 418-423 ◽  
Author(s):  
J. Matjasko ◽  
P. Petrozza ◽  
C. F. Mackenzie
Keyword(s):  
Air Embolism ◽  
Venous Air Embolism ◽  
End Tidal

END-TIDAL NITROGEN AND VENOUS AIR EMBOLISM IN DOGS BREATHING N2O

1985 ◽  
Vol 63 (Supplement) ◽  
pp. A390
Author(s):  
Jane Matjasko ◽  
Gene Daffern ◽  
Bernard Marquis ◽  
Colin Mackenzie
Keyword(s):  
Air Embolism ◽  
Venous Air Embolism ◽  
End Tidal

The efficacy of Doppler monitoring for the detection of venous air embolism

1981 ◽  
Vol 54 (1) ◽  
pp. 75-78 ◽  
Author(s):  
Philip L. Gildenberg ◽  
R. Patrick O'Brien ◽  
William J. Britt ◽  
Elizabeth A. M. Frost
Keyword(s):  
Doppler Ultrasound ◽  
Infusion Rate ◽  
Venous Pressure ◽  
Air Embolism ◽  
Physiological Changes ◽  
Central Venous ◽  
Content Type ◽  
Venous Air Embolism ◽  
Electrocardiographic Changes ◽  
End Tidal

✓ Venous air embolism can usually be detected by the use of a precordial Doppler ultrasound monitor at an air infusion rate as low as 0.015 ml/kg/min, and consistently at a rate of 0.021 ml/kg/min. This is in contrast to previously reported thresholds wherein the first physiological change, a gasp, occurs at 0.36 ml/kg/min, electrocardiographic changes first take place at 0.60 ml/kg/min, drop in blood pressure at 0.69 ml/kg/min, increased central venous pressure at 0.40 ml/kg/min, and end-tidal CO2 decreases at 0.42 ml/kg/min. The first change in heart sounds monitored through an esophageal stethoscope is not detectable until an air infusion rate of 1.70 ml/kg/min, and the classical mill-wheel murmur does not occur until 1.96 ml/kg/min. This demonstrates that Doppler ultrasound can detect venous air embolism before the earliest physiological changes, in contrast to most other methods which do not detect venous air embolism until after cardiopulmonary changes have become well established.

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