Prognostic value of baseline carotid blood flow in critically ill children with septic shock

Background and aim Hemodynamic monitoring and cardiac output (CO) assessment in the ICU have been trending toward less invasive methods. Carotid blood flow (CBF) was suggested as a candidate for CO assessment. The present study aimed to test the value of carotid artery ultrasound analysis in prediction of mortality in pediatric patients with septic shock. Methodology/Principal finding Forty children with septic shock were included in the study. Upon admission, patients were subjected to careful history taking and thorough clinical examination. The consciousness level was assessed by the Glasgow Coma Scale (GCS). Laboratory assessment included complete blood count, C-reactive protein, arterial blood gases, serum electrolytes, and liver and kidney function tests. Electrical cardiometry was used to evaluate hemodynamic parameters. Patients were also subjected to transthoracic 2-D echocardiography. CBF was evaluated using GE Vivid S5 ultrasound device through dedicated software. At the end of study, 14 patients (35.0%) died. It was found that survivors had significantly higher CBF when compared non-survivors [median (IQR): 166.0 (150.0–187.3) versus 141.0 (112.8–174.3), p = 0.033]. In addition, it was noted that survivors had longer ICU stay when compared with non-survivors [16.5 (9.8–31.5) versus 6.5 (3.0–19.5) days, p = 0.005]. ROC curve analysis showed that CBF could significantly distinguish survivors from non-survivors [AUC (95% CI): 0.3 (0.11–0.48), p = 0.035] (Fig 2). Univariate logistic regression analysis identified type of shock [OR (95% CI): 28.1 (4.9–162.4), p<0.001], CI [OR (95% CI): 0.6 (0.43–0.84), p = 0.003] and CBF [OR (95% CI): 0.98 (0.96–0.99), p = 0.031]. However, in multivariate analysis, only type of shock significantly predicted mortality. Conclusions CBF assessment may be a useful prognostic marker in children with septic shock.

Download Full-text

Fetal cardiac bypass alters regional blood flows, arterial blood gases, and hemodynamics in sheep

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1992.263.3.h919 ◽

1992 ◽

Vol 263 (3) ◽

pp. H919-H928 ◽

Cited By ~ 8

Author(s):

S. M. Bradley ◽

F. L. Hanley ◽

B. W. Duncan ◽

R. W. Jennings ◽

J. A. Jester ◽

...

Keyword(s):

Blood Flow ◽

Blood Gases ◽

Arterial Blood Gases ◽

Blood Flows ◽

Arterial Blood ◽

Cardiac Bypass ◽

Regional Blood Flows ◽

Placental Blood ◽

Fetal Organs ◽

Placental Blood Flow

Successful fetal cardiac bypass might allow prenatal correction of some congenital heart defects. However, previous studies have shown that fetal cardiac bypass may result in impaired fetal gas exchange after bypass. To investigate the etiology of this impairment, we determined whether fetal cardiac bypass causes a redistribution of fetal regional blood flows and, if so, whether a vasodilator (sodium nitroprusside) can prevent this redistribution. We also determined the effects of fetal cardiac bypass with and without nitroprusside on fetal arterial blood gases and hemodynamics. Eighteen fetal sheep were studied in utero under general anesthesia. Seven fetuses underwent bypass without nitroprusside, six underwent bypass with nitroprusside, and five were no-bypass controls. Blood flows were determined using radionuclide-labeled microspheres. After bypass without nitroprusside, placental blood flow decreased by 25–60%, whereas cardiac output increased by 15–25%. Flow to all other fetal organs increased or remained unchanged. Decreased placental blood flow after bypass was accompanied by a fall in PO2 and a rise in PCO2. Nitroprusside improved placental blood flow, cardiac output, and arterial blood gases after bypass. Thus fetal cardiac bypass causes a redistribution of regional blood flow away from the placenta and toward the other fetal organs. Nitroprusside partially prevents this redistribution. Methods of improving placental blood flow in the postbypass period may prove critical to the success of fetal cardiac bypass.

Download Full-text

Role of tracheal and bronchial circulation in respiratory heat exchange

Journal of Applied Physiology ◽

10.1152/jappl.1985.58.1.217 ◽

1985 ◽

Vol 58 (1) ◽

pp. 217-222 ◽

Cited By ~ 50

Author(s):

E. M. Baile ◽

R. W. Dahlby ◽

B. R. Wiggs ◽

P. D. Pare

Keyword(s):

Blood Flow ◽

Blood Gases ◽

Lung Parenchyma ◽

Arterial Blood ◽

Respiratory Heat Loss ◽

Reference Flow ◽

Pulmonary Arterial ◽

End Tidal ◽

Humidified Air

Due to their anatomic configuration, the vessels supplying the central airways may be ideally suited for regulation of respiratory heat loss. We have measured blood flow to the trachea, bronchi, and lung parenchyma in 10 anesthetized supine open-chest dogs. They were hyperventilated (frequency, 40; tidal volume 30–35 ml/kg) for 30 min or 1) warm humidified air, 2) cold (-20 degrees C dry air, and 3) warm humidified air. End-tidal CO2 was kept constant by adding CO2 to the inspired ventilator line. Five minutes before the end of each period of hyperventilation, measurements of vascular pressures (pulmonary arterial, left atrial, and systemic), cardiac output (CO), arterial blood gases, and inspired, expired, and tracheal gas temperatures were made. Then, using a modification of the reference flow technique, 113Sn-, 153Gd-, and 103Ru-labeled microspheres were injected into the left atrium to make separate measurements of airway blood flow at each intervention. After the last measurements had been made, the dogs were killed and the lungs, including the trachea, were excised. Blood flow to the trachea, bronchi, and lung parenchyma was calculated. Results showed that there was no change in parenchymal blood flow, but there was an increase in tracheal and bronchial blood flow in all dogs (P less than 0.01) from 4.48 +/- 0.69 ml/min (0.22 +/- 0.01% CO) during warm air hyperventilation to 7.06 +/- 0.97 ml/min (0.37 +/- 0.05% CO) during cold air hyperventilation.

Download Full-text

April 2021 Critical Care Case of the Month: Abnormal Acid-Base Balance in a Post-Partum Woman

Southwest Journal of Pulmonary and Critical Care ◽

10.13175/swjpcc007-21 ◽

2021 ◽

Vol 22 (4) ◽

pp. 81-85

Author(s):

Mohammad Mahmoud ◽

Keyword(s):

Emergency Department ◽

Complete Blood Count ◽

Post Partum ◽

Healthy Woman ◽

Blood Gases ◽

Ambient Air ◽

Physical Exam ◽

Acid Base Balance ◽

Arterial Blood ◽

Base Balance

No abstract available. Article truncated after first page. History of Present Illness: A 29-year-old healthy woman, who is 8 weeks postpartum, presented to the emergency department with severe shortness of breath, fast shallow breathing, nausea, several episodes of nonbloody nonbilious emesis, abdominal pain and malaise for 1 week. The patient delivered a healthy boy at full-term by spontaneous vaginal delivery. Her pregnancy was uneventful. She denied smoking or use of alcohol. Physical Exam: On presentation to the emergency department her blood pressure was found to be 121/71, temperature 36.8°C, pulse 110 beats per minute, respiratory rate 20 breaths per minute and SpO2 saturation of 99% while breathing ambient air. Physical exam was remarkable except for dry mucous membranes, sinus tachycardia, and tachypnea with mild epigastric tenderness with light palpation. Which of the following should be done? 1. Complete blood count (CBC) 2. Metabolic panel 3. Chest x-ray 4. Arterial blood gases (ABGs) 5. All of the above …

Download Full-text

Hyperlactacemia in critically ill children: comparison of traditional and Fencl-Stewart methods

Paediatrica Indonesiana ◽

10.14238/pi47.1.2007.35-41 ◽

2007 ◽

Vol 47 (1) ◽

pp. 35

Author(s):

Hari Kushartono ◽

Antonius H. Pudjiadi ◽

Susetyo Harry Purwanto ◽

Imral Chair ◽

Darlan Darwis ◽

...

Keyword(s):

Base Excess ◽

Pediatric Intensive Care ◽

Blood Gases ◽

Critically Ill Children ◽

Strongly Correlated ◽

Acid Base ◽

Arterial Blood ◽

Acid Base Status ◽

Lactate Levels ◽

Elevated Lactate

Background Base excess is a single variable used to quantifymetabolic component of acid base status. Several researches havecombined the traditional base excess method with the Stewartmethod for acid base physiology called as Fencl-Stewart method.Objective The purpose of the study was to compare two differentmethods in identifying hyperlactacemia in pediatric patients withcritical illness.Methods The study was performed on 43 patients admitted tothe pediatric intensive care unit of Cipto MangunkusumoHospital, Jakarta. Sodium, potassium, chloride, albumin, lactateand arterial blood gases were measured. All samples were takenfrom artery of all patients. Lactate level of >2 mEq/L was definedas abnormal. Standard base excess (SBE) was calculated fromthe standard bicarbonate derived from Henderson-Hasselbalchequation and reported on the blood gas analyzer. Base excessunmeasured anions (BE UA ) was calculated using the Fencl-Stewartmethod simplified by Story (2003). Correlation between lactatelevels in traditional and Fencl-Stewart methods were measuredby Pearson’s correlation coefficient .Results Elevated lactate levels were found in 24 (55.8%) patients.Lactate levels was more strongly correlated with BE UA (r = - 0.742,P<0.01) than with SBE (r = - 0.516, P<0.01).Conclusion Fencl-Stewart method is better than traditionalmethod in identifying patients with elevated lactate levels, so theFencl-Stewart method is suggested to use in clinical practice.

Download Full-text

Measuring the human ventilatory and cerebral blood flow response to CO2: a technical consideration for the end-tidal-to-arterial gas gradient

Journal of Applied Physiology ◽

10.1152/japplphysiol.00787.2015 ◽

2016 ◽

Vol 120 (2) ◽

pp. 282-296 ◽

Cited By ~ 31

Author(s):

Michael M. Tymko ◽

Ryan L. Hoiland ◽

Tomas Kuca ◽

Lindsey M. Boulet ◽

Joshua C. Tremblay ◽

...

Keyword(s):

Blood Flow ◽

Minute Ventilation ◽

Linear Regression Analysis ◽

Blood Gases ◽

Prediction Equation ◽

Flow Response ◽

Arterial Blood ◽

Reactivity Test ◽

End Tidal ◽

Gas Gradients

Our aim was to quantify the end-tidal-to-arterial gas gradients for O2 (PET-PaO2) and CO2 (Pa-PETCO2) during a CO2 reactivity test to determine their influence on the cerebrovascular (CVR) and ventilatory (HCVR) response in subjects with (PFO+, n = 8) and without (PFO−, n = 7) a patent foramen ovale (PFO). We hypothesized that 1) the Pa-PETCO2 would be greater in hypoxia compared with normoxia, 2) the Pa-PETCO2 would be similar, whereas the PET-PaO2 gradient would be greater in those with a PFO, 3) the HCVR and CVR would be underestimated when plotted against PETCO2 compared with PaCO2, and 4) previously derived prediction algorithms will accurately target PaCO2. PETCO2 was controlled by dynamic end-tidal forcing in steady-state steps of −8, −4, 0, +4, and +8 mmHg from baseline in normoxia and hypoxia. Minute ventilation (V̇E), internal carotid artery blood flow (Q̇ICA), middle cerebral artery blood velocity (MCAv), and temperature corrected end-tidal and arterial blood gases were measured throughout experimentation. HCVR and CVR were calculated using linear regression analysis by indexing V̇E and relative changes in Q̇ICA, and MCAv against PETCO2, predicted PaCO2, and measured PaCO2. The Pa-PETCO2 was similar between hypoxia and normoxia and PFO+ and PFO−. The PET-PaO2 was greater in PFO+ by 2.1 mmHg during normoxia ( P = 0.003). HCVR and CVR plotted against PETCO2 underestimated HCVR and CVR indexed against PaCO2 in normoxia and hypoxia. Our PaCO2 prediction equation modestly improved estimates of HCVR and CVR. In summary, care must be taken when indexing reactivity measures to PETCO2 compared with PaCO2.

Download Full-text

Continuous Airway Pressure Breathing With the Head-Box in the Newborn Lamb: Effects on Regional Blood Flows

PEDIATRICS ◽

10.1542/peds.59.6.858 ◽

1977 ◽

Vol 59 (6) ◽

pp. 858-864

Author(s):

G. Gabriele ◽

C. R. Rosenfeld ◽

D. E. Fixler ◽

J. M. Wheeler

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Airway Pressure ◽

Left Ventricular Pressure ◽

Blood Gases ◽

Ocular Blood Flow ◽

Left Ventricular ◽

Positive Pressure ◽

Blood Flows ◽

Arterial Blood

Continuous airway pressure delivered by a head-box is an accepted means of treating clinical hyaline membrane disease. To investigate hemodynamic alterations resulting from its use, eight newborn lambs, 1 to 6 days of age, were studied at 6 and 11 mm Hg of positive pressure, while spontaneously breathing room air. Organ blood flows and cardiac output were measured with 25 µ-diameter radioactive microspheres. Heart rate, left ventricular pressure, and arterial blood gases did not change during the study. Jugular venous pressures increased from 6.4 mm Hg to 18.6 and 24.2 mm Hg at 6 and 11 mm Hg, respectively (P < .005). Cardiac output decreased approximately 20% at either intrachamber pressure setting. Renal blood flow fell 21% at 11 mm Hg. No significant changes in blood flow were found in the brain, gastrointestinal tract, spleen, heart, or liver when compared to control flows. Of particular interest was the finding of a 28% reduction in ocular blood flow at 6 mm Hg and 52% at 11 mm Hg. From these results, we conclude that substantial cardiovascular alterations may occur during the application of head-box continuous airway pressure breathing, including a significant reduction in ocular blood flow.

Download Full-text

The Contribution of Arterial Blood Gases in Cerebral Blood Flow Regulation and Fuel Utilization in Man at High Altitude

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2015.4 ◽

2015 ◽

Vol 35 (5) ◽

pp. 873-881 ◽

Cited By ~ 25

Author(s):

Christopher K Willie ◽

David B MacLeod ◽

Kurt J Smith ◽

Nia C Lewis ◽

Glen E Foster ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

High Altitude ◽

Cerebral Metabolism ◽

Venous Blood ◽

Blood Gases ◽

Cerebrovascular Reactivity ◽

Arterial Blood Gases ◽

Arterial Blood ◽

Cerebrovascular Function

The effects of partial acclimatization to high altitude (HA; 5,050 m) on cerebral metabolism and cerebrovascular function have not been characterized. We hypothesized (1) increased cerebrovascular reactivity (CVR) at HA; and (2) that CO2 would affect cerebral metabolism more than hypoxia. PaO2 and PaCO2 were manipulated at sea level (SL) to simulate HA exposure, and at HA, SL blood gases were simulated; CVR was assessed at both altitudes. Arterial–jugular venous differences were measured to calculate cerebral metabolic rates and cerebral blood flow (CBF). We observed that (1) partial acclimatization yields a steeper CO2-H+ relation in both arterial and jugular venous blood; yet (2) CVR did not change, despite (3) mean arterial pressure (MAP)-CO2 reactivity being doubled at HA, thus indicating effective cerebral autoregulation. (4) At SL hypoxia increased CBF, and restoration of oxygen at HA reduced CBF, but neither had any effect on cerebral metabolism. Acclimatization resets the cerebrovasculature to chronic hypocapnia.

Download Full-text

Effect of autonomic blockade on tracheobronchial blood flow

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.2.520 ◽

1987 ◽

Vol 62 (2) ◽

pp. 520-525 ◽

Cited By ~ 9

Author(s):

E. M. Baile ◽

S. Osborne ◽

P. D. Pare

Keyword(s):

Blood Flow ◽

Blood Gases ◽

Lung Parenchyma ◽

Beta Blockade ◽

Humid Air ◽

Dry Air ◽

Arterial Blood ◽

Autonomic Blockade ◽

Alpha Blockade ◽

Group 2

Tracheobronchial blood flow increases two to five times in response to cold and warm dry air hyperventilation in anesthetized tracheostomized dogs. In this series of experiments we have attempted to attenuate this increase by blockade of the autonomic nervous system. Four groups of anesthetized, tracheostomized, open-chest dogs were studied. Group 1 (n = 5) were hyperventilated for 30 min with 1) warm humid [approximately 26 degrees C, 100% relative humidity, (rh)] air followed by bilateral vagotomy, 2) warm humid air, 3) cold (-22 degrees C, 0% rh) dry air, and 4) warm humid air. Groups 2, 3, and 4 (n = 3/group) were hyperventilated for 30 min with 1) warm humid (approximately 41 degrees C, 100% rh) air, 2) warm dry (approximately 41 degrees C) air, 3) warm humid air, and 4) warm dry air. Group 2 were controls. Group 3 were given phentolamine, 0.6 mg/kg intravenously, as an alpha-blockade, and group 4 were given propranolol, 1 mg/kg, as a beta-blockade after warm dry air hyperventilation (period 2). Five minutes before the end of each 30-min period of hyperventilation, measurements of vascular pressures, cardiac output, arterial blood gases, and inspired, body, and tracheal temperatures were measured, and differently labeled radioactive microspheres were injected into the left atrium to make separate measurements of airway blood flow. After the last measurements had been made animals were killed and their lungs were excised. Blood flow to the airways and lung parenchyma was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

Cardiovascular effects of acute hemorrhage in fetal lambs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1981.240.1.h45 ◽

1981 ◽

Vol 240 (1) ◽

pp. H45-H48 ◽

Cited By ~ 3

Author(s):

P. L. Toubas ◽

N. H. Silverman ◽

M. A. Heymann ◽

A. M. Rudolph

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Blood Volume ◽

Age Groups ◽

Blood Gases ◽

Cardiovascular Effects ◽

Carbon Dioxide Tension ◽

Acute Hemorrhage ◽

Arterial Blood ◽

Placental Blood

The effects of acute hemorrhage were studied in two groups each with six fetal lambs (100-116 amd 128-147 days gestation) 3-4 days after we implanted catheters. Fetal blood pressures, heart rate, arterial blood gases and pH, and combined ventricular output and its distribution (radionuclide-labeled microsphere technique) were measured before and 5 min after removal of 15% of fetal-placental blood volume measured by 125I-albumin dilution. Because there were no differences in responses in the two age groups, the data were pooled. Fetal arterial mean pressure fell significantly (50.7 +/- 2.5 to 45.5 +/- 2.6 mmHg) as did heart rate (186 +/- 6 to 151 +/- 13 beats/min) and arterial blood pH (7.39 +/- 0.02 to 7.30 +/- 0.02); arterial blood carbon dioxide tension rose (39.7 +/- 29 to 44.1 +/- 4.4). Combined ventricular output fell from 610 +/- 58 to 448 +/- 45 ml . kg-1 . min-1 (P < 0.05). Blood flow to the umbilical-placental circulation, as well as to the fetal body, fell significantly. Blood flow to the kidneys, gastrointestinal tracts, and lungs also fell, but flow to other organs was maintained. Blood volume reduction in the fetus markedly influences blood gas exchange, because it results in a reduction of umbilical-placental blood flow associated with the fall in arterial pressure.

Download Full-text