Venous air embolism in swine: transport of gas bubbles through the pulmonary circulation

The assumption that the lung is an effective filter for gas bubbles is of importance for certain occupations (e.g., divers, astronauts) as well as in the accomplishment of several medical procedures. The filtering capacity was tested in pigs by use of continuous air infusion into the right ventricle and a transesophageal echocardiographic transducer for detection of air in the left atrium. Twenty pigs, anesthetized with pentobarbital sodium and mechanically ventilated, were divided into groups that received air at infusion rates of 0.05 (group 1a, n = 7), 0.10 (group 2, n = 6), and 0.20 (group 3, n = 5) ml.kg-1.min-1. Two pigs served as controls. The breakthrough incidence was 0, 67, and 100%, respectively. Group 1a received a second infusion of 0.10 ml.kg-1.min-1 (group 1b, n = 7), and spillover of bubbles occurred in only 14% of these pigs. Infusion of gas caused a maximum increase in mean pulmonary arterial pressure (PAP) of 129 +/- 9% to 39.2 +/- 1.3 (SE) mmHg, with no significant difference between the groups. Breakthrough was observed only in animals with a dramatic reduction in mean arterial pressure and a PAP that returned to almost-normal values at spillover time. Our results suggest that the threshold value for breakthrough of air bubbles in pigs is reduced compared with that in dogs. The hemodynamic consequences at a given infusion rate are, however, greatly enhanced.

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Effect of aminophylline on transpulmonary passage of venous air emboli in pigs

Journal of Applied Physiology ◽

10.1152/jappl.1991.71.5.1780 ◽

1991 ◽

Vol 71 (5) ◽

pp. 1780-1786 ◽

Cited By ~ 5

Author(s):

A. Vik ◽

B. M. Jenssen ◽

A. O. Brubakk

Keyword(s):

Arterial Pressure ◽

Bolus Injection ◽

Air Embolism ◽

Air Bubbles ◽

Mechanically Ventilated ◽

Venous Air Embolism ◽

Arterial Circulation ◽

Mean Pulmonary Arterial Pressure ◽

Pulmonary Arterial ◽

The Right

Aminophylline has been shown to dramatically reduce the filtering capacity of the lung in dogs during venous air embolism. Similarities have been pointed out between the cardiovascular and respiratory systems of the pig and of humans. We therefore wanted to find out whether aminophylline also modifies the transpulmonary spillover of microbubbles to the arterial circulation of the pig. Twenty-eight pigs were anesthetized with pentobarbital sodium and mechanically ventilated. Aminophylline was injected intravenously into 10 of the pigs before the introduction of air bubbles into the right ventricle, while the other 18 pigs served as controls. A transesophageal echocardiographic probe was used to detect eventual air bubbles in the left atrium or in the aorta. Pigs received either air infusion, at rates varying from 0.05 to 0.20 ml.kg-1.min-1, or calibrated microbubbles, 5–300 microns diam. We found that aminophylline-treated pigs did not show any change in spillover incidence compared with controls. Furthermore, in both groups the spillover during continuous air infusion seemed to be a preterminal event, because the pigs had very low arterial pressure when arterial bubbles were observed. Finally, there was an increase in mean pulmonary arterial pressure from 18 +/- 3.4 to 26 +/- 2.2 (SD) mmHg (n = 4, P less than 0.01) in aminophylline-treated pigs after a bolus injection of microbubbles (less than or equal to 50 microns, total volume less than 0.5 ml). Our results suggest that aminophylline does not modify the transpulmonary passage of microbubbles in this porcine model. In addition, it would seem that the pulmonary circulation of the pig is sensitive to very small volumes of air, when injected as microbubbles.

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Effect of the degree of head elevation on the incidence and severity of venous air embolism in cranial neurosurgical procedures with patients in the semisitting position

Journal of Neurosurgery ◽

10.3171/2017.1.jns162489 ◽

2018 ◽

Vol 128 (5) ◽

pp. 1560-1569 ◽

Cited By ~ 6

Author(s):

Hatice Türe ◽

M. Volkan Harput ◽

Nural Bekiroğlu ◽

Özgül Keskin ◽

Özge Köner ◽

...

Keyword(s):

Transesophageal Echocardiography ◽

Air Embolism ◽

Neurosurgical Procedures ◽

Hemodynamic Changes ◽

Venous Air Embolism ◽

Head Elevation ◽

Significant Difference ◽

Group 2 ◽

Anesthetic Complications ◽

Group 1

OBJECTIVEThe semisitting position of a patient confers numerous advantages in various neurosurgical procedures, but venous air embolism is one of the associated complications of this position. To date, no prospective studies of the relationship between the degree of head elevation and the rate and severity of venous air embolism for patients undergoing a procedure in this position have been performed. In this study, the authors compared changes in the severity of venous air embolism according to the degree of head elevation (30° or 45°) in patients undergoing an elective cranial neurosurgical procedure in the semisitting position.METHODSOne hundred patients undergoing an elective infratentorial craniotomy in the semisitting position were included, and each patient was assigned to 1 of 2 groups. In Group 1, each patient’s head was elevated 30° during surgery, and in Group 2, each patient’s head elevation was 45°. Patients were assigned to their group according to the location of their lesion. During surgery, the standard anesthetic protocol was used with total intravenous anesthesia, and transesophageal echocardiography was used to detect air in the blood circulation. Any air embolism seen on the echocardiography screen was classified as Grade 0 to 4. If multiple events occurred, the worst graded attack was used for statistical analysis. During hemodynamic changes caused by emboli, fluid and vasopressor requirements were recorded. Surgical and anesthetic complications were recorded also. All results were compared statistically, and a p value of < 0.05 was considered statistically significant.RESULTSThere was a statistically significant difference between groups for the total rates of venous air emboli detected on transesophageal echocardiography (22.0% [n = 11] in Group 1 and 62.5% [n = 30] in Group 2; p < 0.0001). The rate and severity of air embolism were significantly lower in Group 1 than in Group 2 (p < 0.001). The rates of clinically important venous air embolism (Grade 2, 3, or 4, venous air embolism with decreased end-tidal carbon dioxide levels and/or hemodynamic changes) were 8.0% (n = 4) in Group 1 and 50.0% (n = 24) in Group 2 (p < 0.0001). There was no association between the rate and severity of venous air embolism with patient demographics (p > 0.05). An association was found, however, between the rate of venous air embolism and the type of surgical pathology (p < 0.001); venous embolism occurred more frequently in patients with a meningioma. There were no major surgical or anesthetic complications related to patient position during the postoperative period.CONCLUSIONSFor patients in the semisitting position, an increase in the degree of head elevation is related directly to a higher rate of venous air embolism. With a 30° head elevation and our standardized technique of positioning, the semisitting position can be used safely in neurosurgical practice.

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EPICARDIAL PACING

The Professional Medical Journal ◽

10.29309/tpmj/2010.17.01.1980 ◽

2010 ◽

Vol 17 (01) ◽

pp. 55-58

Author(s):

ZAHID PARVEZ ◽

FARID AHMAD CHAUDHARY ◽

AJMAL HASAN NAZQVI ◽

Muniza Saeed

Keyword(s):

Cardiac Surgery ◽

Artery Bypass ◽

Left Ventricular ◽

Right Atrial ◽

Routine Practice ◽

Optimum Time ◽

Pacing Threshold ◽

Significant Difference ◽

Group 2 ◽

The Right

Placement of epicardial wires on the right atrial and right ventricle surfaces is a routine practice in cardiac surgery. These pacingelectrodes are used for invasive pacing of the myocardium for a variety of emergent and elective conditions postoperatively. There is uncertaintyin actual practice about the optimum time for their removal, and practice varies widely between different institutions. Objectives: To determine thetime related efficacy of these pacing electrodes after cardiac surgery, to find out the optimum time of their removal. Period: July 2008 toOctober 2008. Patients & Methods: 47 patients those underwent coronary artery bypass surgery were prospectively enrolled and evaluatedwith standard 12 lead ECG and ventricle pacing threshold immediately after surgery and on the 5t h postoperative day. The patients were dividedinto two subgroups according to their left ventricle ejection fraction ( > 40% verses < 40%). Results: There was significant difference in theeffective pacing threshold in groupl and 2 on immediate post operative period and on day 5. (P = 0.002 and P = 0.02 respectively) The sensingthreshold immediately after operation and on 5t h post operative day also differed significantly (P = 0.009 in group 1 and 0.02 in group 2) Theeffective VVI* pacing was lost in 17 patients (40.5%) on the 5t h post operative day and comparison of effective pacing threshold in the twogroups showed no significant difference during the same period of time (P = NS). "Ventrculo-ventrical inhibition. Conclusions: The epicardialpacing wires have little usefulness after the fifth postoperative day and should be removed by this time. In addition postoperative pacingthreshold was not affected by the decreased left ventricular function.

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Study of the Entropy as a Way to Detect Venous Air Embolism Using a Pre-cordial Doppler

U Porto Journal of Engineering ◽

10.24840/10.24840/2183-6493_001.002_0005 ◽

2015 ◽

Vol 1 (2) ◽

pp. 39-44

Author(s):

Ana Tedim ◽

Pedro Amorim ◽

Ana Castro

Keyword(s):

Heart Sound ◽

Air Embolism ◽

Robust Methods ◽

Clinical Protocol ◽

Venous Air Embolism ◽

Air Bubble ◽

Cardiac Sound ◽

Flow Turbulence ◽

The Right ◽

Increased Blood Flow

Venous air embolism (VAE) is the air bubble accumulation in the right side of the heart, or in the pulmonary region. Pre-cordial Doppler allows a real-time monitoring of heart sound and is used to detect VAE episodes through changes in cardiac sound. Sometimes these changes are not detected by the operator, which reveals the importance of finding other robust methods for VAE detection. This work aims to study entropy as a feature of the heart sound that may provide useful information on VAE episodes.A clinical protocol was designed: Doppler Heart Sound (DHS) was collected at baseline, and following infusions of saline with 4 distinct volumes and 2 infusion rates, and given through 2 infusion vias, to 4 patients enrolled in the clinical study. Entropy of these segments was obtained, and relation between the extracted feature and saline infusions was studied.Entropy presents a good performance showing an increase in response to saline injections (increased blood flow turbulence).

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Hyperuricemia in patients with pulmonary hypertension: A study in a tertiary care center

IP Indian Journal of Immunology and Respiratory Medicine ◽

10.18231/j.ijirm.2021.038 ◽

2021 ◽

Vol 6 (3) ◽

pp. 173-177

Author(s):

C H Raju ◽

M Ravindranath

Keyword(s):

Pulmonary Hypertension ◽

Uric Acid ◽

Arterial Pressure ◽

Serum Uric Acid ◽

Pulmonary Arterial Pressure ◽

Nyha Class ◽

High Serum ◽

Mean Pulmonary Arterial Pressure ◽

Pulmonary Arterial ◽

The Right

Pulmonary Hypertension is one of a life-threatening disease with high rate of patient mortality. Decreased cardiac output and tissue hypoxia is measured using Uric acid as a marker for assessment of pulmonary hypertension. 75 patients who were diagnosed with a mean pulmonary arterial pressure of >22mmHg were categorized as group A and 75 healthy patients were considered to be Group B. Blood was collected for Uric acid, creatinine and total Bilirubin estimation. Pulmonary arterial systolic pressure as well as the ventricular function of the patients was evaluated using Colour Doppler ECG and a value of ≥50 mmHg, or a mean pulmonary arterial pressure (at rest) of ≥25 mmHg was taken and the right arterial pressure was calculated. Using the Simpson’s formula, the right and left ventricular ejaculation factors (RVEF, LVEF) were calculated. The serum uric acid levels among the patients were 8.3±1.4mg/dL, creatinine levels were 2.1 ± 0.5 mg/dL, and the total bilirubin levels were 1.9 ± 0.8 mg/dL all of which was significantly higher than the controls. The uric acid levels were also positively correlated to the NHYA class. The blood pressure and the pulmonary arterial pressure were also higher than that of the controls. The correlation was done between the elevated uric acid and ejection fractions and the correlation coefficients of MPAP, LVEF, RVEF and the NYHA class were all significantly associated and the values were 0.394, -0.513, -0.467 and 0.38 respectively. High serum uric acid levels is significantly associated with higher blood pressure, pulmonary arterial pressure and NYHA class. High serum uric acid levels can be a reliable prognostic marker for the detection of pulmonary hypertension. Early therapy may help in the reduction of mortality rate.

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Cerebral Venous Air Embolism due to a Hidden Skull Fracture Secondary to Head Trauma

Case Reports in Neurological Medicine ◽

10.1155/2015/730808 ◽

2015 ◽

Vol 2015 ◽

pp. 1-3

Author(s):

Ai Hosaka ◽

Tetsuto Yamaguchi ◽

Fumiko Yamamoto ◽

Yasuro Shibagaki

Keyword(s):

Head Trauma ◽

Superior Sagittal Sinus ◽

Skull Fracture ◽

Air Embolism ◽

Skull Fractures ◽

Venous Air Embolism ◽

Sagittal Sinus ◽

The Right ◽

Head Computed Tomography

Cerebral venous air embolism is sometimes caused by head trauma. One of the paths of air entry is considered a skull fracture. We report a case of cerebral venous air embolism following head trauma. The patient was a 55-year-old man who fell and hit his head. A head computed tomography (CT) scan showed the air in the superior sagittal sinus; however, no skull fractures were detected. Follow-up CT revealed a fracture line in the right temporal bone. Cerebral venous air embolism following head trauma might have occult skull fractures even if CT could not show the skull fractures.

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The Effect of Biopolymer Coatings on Hernia Meshes in a Rat Model

Annals of Surgery and Perioperative Care ◽

10.26420/annsurgperiopercare.2021.1045 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Scheuerlein H ◽

◽

Eisold C ◽

Keyword(s):

Mechanical Strength ◽

Rectus Sheath ◽

Giant Cells ◽

Scar Tissue ◽

Tissue Reaction ◽

Wilcoxon Test ◽

Surrounding Tissue ◽

Significant Difference ◽

Group 2 ◽

The Right

Purpose: To improve biocompatibility and texture of hernia meshes has played a key role in tissue engineering for decades. Biopolymer (Polyethylenimine (PEI) and 3-Glycidoxypropyltrimethoxysilane (GOPS)) coating on Polypropylene (PP) and expanded Polytetrafluoroethylene (ePTFE) mesh showed promising results in fibroblast adhesion and cell growth in an invitro analysis. The objective of this animal study was to evaluate whether this may influence the incorporation into host tissue. Methods: 30 male Lewis rats were divided into 3 groups (n=10): Group 1: ePTFE/PEI, Group 2: ePTFE/GOPS, Group 3: PP/PEI. In each animal, a 3x0.5 cm coated mesh was implanted in the right rectus sheath in sublay position, the uncoated mesh was implanted on the left equally. After 90 days, the rats were sacrificed and each side of the rectus sheath was analyzed separately for adhesions and mechanical strength. Histopathological assessment included Gieson’s stain and haematoxylin-eosin staining. The Wilcoxon test was used for statistical analyses. Results: The GOPS-coated ePTFE tends to cause more adhesions. There was no significant difference in the mechanical strength within and between the groups, but the PEI-coated polypropylene was significantly less extendible (p<0.05) compared to the uncoated PP. In group 2, Gieson’s stain showed a significantly lower surrounding tissue reaction of foreign-body giant cells and scar tissue around the PEI-coated mesh compared to the uncoated ePTFE (p<0.05). Conclusions: It is possible to coat surgical mesh devices with biopolymers. They do not lead to a lack of mechanical strength. The GOPS-coating did not show any general positive effect on the biocompatibility of meshes. The PEIcoating resulted in a lower surrounding tissue reaction and in a less extendible abdominal wall and should therefore be investigated further.

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Effect of ventilation with soluble and diffusible gases on the size of air emboli

Journal of Applied Physiology ◽

10.1152/jappl.1991.70.3.1068 ◽

1991 ◽

Vol 70 (3) ◽

pp. 1068-1074 ◽

Cited By ~ 8

Author(s):

R. G. Presson ◽

K. R. Kirk ◽

K. A. Haselby ◽

W. W. Wagner

Keyword(s):

Pulmonary Hypertension ◽

Nitrous Oxide ◽

Pulmonary Artery ◽

Direct Proof ◽

Air Embolism ◽

Air Bubbles ◽

Venous Air Embolism ◽

Vascular Obstruction ◽

The Right

Pulmonary hypertension resulting from venous air embolism is known to increase after ventilation with highly soluble and diffusible gases. Exacerbation of the hypertension could be due to further blockage of the circulation if the bubbles enlarge as a result of ingress of gas by diffusion. This mechanism has been frequently cited but lacks direct proof. To determine directly whether intravascular air bubbles actually enlarge when highly soluble and diffusible gases are inspired, we used microscopy to measure the size of gas emboli in vivo. When air bubbles were injected into the right atrium, the bubbles that appeared in pulmonary arterioles were larger during ventilation with helium or nitrous oxide than with air. Air bubbles injected into the pulmonary artery enlarged when the inspired gas was changed to helium or nitrous oxide. The direction, magnitude, and timing of changes in bubble size were consistent with a net diffusion of gas into the bubbles. These data support the idea that venous air emboli enlarge during ventilation with soluble and diffusible gases and thereby cause further vascular obstruction.

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Right atrium and renal sodium excretion

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.228.1.184 ◽

1975 ◽

Vol 228 (1) ◽

pp. 184-190 ◽

Cited By ~ 5

Author(s):

SO Stitzer ◽

RL Malvin

Keyword(s):

Mean Arterial Pressure ◽

Arterial Pressure ◽

Right Atrium ◽

Venous Pressure ◽

Right Atrial ◽

Binary Response ◽

Balloon Inflation ◽

Water Excretion ◽

Significant Difference ◽

The Right

Inflation of a balloon in the right atrium of 13 dogs resulted in salt and water retention not attributable to changes in GFR, RPF, filtration fraction, mean arterial pressure, left atrial pressure, or renal venous pressure. The response to right atrial balloon inflation was compared with the renal effects of constriction of the abdominal aorta above the renal arteries and constriction of the ascending aorta. Neither procedure evoked the same response as balloon inflation. Results suggest that the decrease in mean arterial pressure which accompanies balloon inflation accounts for only part of the decreased salt and water excretion. There was no significant difference between the responses of denervated and intact kidneys to right atrial balloon inflation. A binary response to stretching of the right atrium is suggested, both components apparently involving hormonal mediation.

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