Impact of bedside percutaneous dilational and open surgical tracheostomy on intracranial pressure, pulmonary gas exchange, and hemodynamics in neurocritical care patients

Severe anemia is associated with remarkable stability of pulmonary gas exchange (S. Deem, M. K. Alberts, M. J. Bishop, A. Bidani, and E. R. Swenson. J. Appl. Physiol. 83: 240–246, 1997), although the factors that contribute to this stability have not been studied in detail. In the present study, 10 Flemish Giant rabbits were anesthetized, paralyzed, and mechanically ventilated at a fixed minute ventilation. Serial hemodilution was performed in five rabbits by simultaneous withdrawal of blood and infusion of an equal volume of 6% hetastarch; five rabbits were followed over a comparable time. Ventilation-perfusion (V˙a/Q˙) relationships were studied by using the multiple inert-gas-elimination technique, and pulmonary blood flow distribution was assessed by using fluorescent microspheres. Expired nitric oxide (NO) was measured by chemiluminescence. Hemodilution resulted in a linear fall in hematocrit over time, from 30 ± 1.6 to 11 ± 1%. Anemia was associated with an increase in arterial [Formula: see text] in comparison with controls ( P < 0.01 between groups). The improvement in O2 exchange was associated with reducedV˙a/Q˙heterogeneity, a reduction in the fractal dimension of pulmonary blood flow ( P = 0.04), and a relative increase in the spatial correlation of pulmonary blood flow ( P = 0.04). Expired NO increased with anemia, whereas it remained stable in control animals ( P < 0.0001 between groups). Anemia results in improved gas exchange in the normal lung as a result of an improvement in overallV˙a/Q˙matching. In turn, this may be a result of favorable changes in pulmonary blood flow distribution, as assessed by the fractal dimension and spatial correlation of blood flow and as a result of increased NO availability.

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Pulmonary Gas Exchange in Candidates for Surgical Treatment of Ischaemic Heart Disease

Respiration ◽

10.1159/000193870 ◽

1978 ◽

Vol 35 (3) ◽

pp. 136-147 ◽

Cited By ~ 1

Author(s):

P. Jebavý ◽

J. Fabián ◽

M. Henzlová ◽

A. Belán

Keyword(s):

Heart Disease ◽

Surgical Treatment ◽

Gas Exchange ◽

Ischaemic Heart Disease ◽

Pulmonary Gas Exchange

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Surgical tracheostomy in a cohort of COVID-19 patients

HNO ◽

10.1007/s00106-021-01021-4 ◽

2021 ◽

Author(s):

Patrick J. Schuler ◽

Jens Greve ◽

Thomas K. Hoffmann ◽

Janina Hahn ◽

Felix Boehm ◽

...

Keyword(s):

Mechanical Ventilation ◽

Respiratory Failure ◽

Prolonged Mechanical Ventilation ◽

Tertiary Care ◽

Lung Compliance ◽

Hypoxemic Respiratory Failure ◽

Surgical Tracheostomy ◽

Increased Risk ◽

Open Surgical Tracheostomy ◽

Sedative Drugs

Abstract Background One of the main symptoms of severe infection with the new coronavirus‑2 (SARS-CoV-2) is hypoxemic respiratory failure because of viral pneumonia with the need for mechanical ventilation. Prolonged mechanical ventilation may require a tracheostomy, but the increased risk for contamination is a matter of considerable debate. Objective Evaluation of safety and effects of surgical tracheostomy on ventilation parameters and outcome in patients with COVID-19. Study design Retrospective observational study between March 27 and May 18, 2020, in a single-center coronavirus disease-designated ICU at a tertiary care German hospital. Patients Patients with COVID-19 were treated with open surgical tracheostomy due to severe hypoxemic respiratory failure requiring mechanical ventilation. Measurements Clinical and ventilation data were obtained from medical records in a retrospective manner. Results A total of 18 patients with confirmed SARS-CoV‑2 infection and surgical tracheostomy were analyzed. The age range was 42–87 years. All patients received open tracheostomy between 2–16 days after admission. Ventilation after tracheostomy was less invasive (reduction in PEAK and positive end-expiratory pressure [PEEP]) and lung compliance increased over time after tracheostomy. Also, sedative drugs could be reduced, and patients had a reduced need of norepinephrine to maintain hemodynamic stability. Six of 18 patients died. All surgical staff were equipped with N99-masks and facial shields or with powered air-purifying respirators (PAPR). Conclusion Our data suggest that open surgical tracheostomy can be performed without severe complications in patients with COVID-19. Tracheostomy may reduce invasiveness of mechanical ventilation and the need for sedative drugs and norepinehprine. Recommendations for personal protective equipment (PPE) for surgical staff should be followed when PPE is available to avoid contamination of the personnel.

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Pulmonary Gas Exchange and Oxygen Uptake During Exercise in Patients with Type 1 Diabetes Mellitus

Diabetic Medicine ◽

10.1111/j.1464-5491.1992.tb01771.x ◽

1992 ◽

Vol 9 (3) ◽

pp. 252-257 ◽

Cited By ~ 26

Author(s):

Th. Wanke ◽

D. Formanek ◽

M. Auinger ◽

H. Zwick ◽

K. Irsigler

Keyword(s):

Diabetes Mellitus ◽

Type 1 Diabetes ◽

Gas Exchange ◽

Oxygen Uptake ◽

Type 1 Diabetes Mellitus ◽

Pulmonary Gas Exchange

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Specifics of pulmonary gas exchange after replacing the inert components of inspired mixtures

Doklady Biological Sciences ◽

10.1134/s0012496615020027 ◽

2015 ◽

Vol 461 (1) ◽

pp. 69-72

Author(s):

V. P. Nikolaev

Keyword(s):

Gas Exchange ◽

Pulmonary Gas Exchange

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Ventilation-perfusion imbalance and chronic obstructive pulmonary disease staging severity

Journal of Applied Physiology ◽

10.1152/japplphysiol.00085.2009 ◽

2009 ◽

Vol 106 (6) ◽

pp. 1902-1908 ◽

Cited By ~ 102

Author(s):

Roberto Rodríguez-Roisin ◽

Mitra Drakulovic ◽

Diego A. Rodríguez ◽

Josep Roca ◽

Joan Albert Barberà ◽

...

Keyword(s):

Chronic Obstructive Pulmonary Disease ◽

Gas Exchange ◽

Pulmonary Disease ◽

Forced Expiratory Volume ◽

Pulmonary Gas Exchange ◽

Airflow Limitation ◽

Chronic Obstructive ◽

Obstructive Pulmonary Disease ◽

Gold Stage ◽

Stage 1

Chronic obstructive pulmonary disease (COPD) is characterized by a decline in forced expiratory volume in 1 s (FEV1) and, in many advanced patients, by arterial hypoxemia with or without hypercapnia. Spirometric and gas exchange abnormalities have not been found to relate closely, but this may reflect a narrow range of severity in patients studied. Therefore, we assessed the relationship between pulmonary gas exchange and airflow limitation in patients with COPD across the severity spectrum. Ventilation-perfusion (V̇A/Q̇) mismatch was measured using the multiple inert gas elimination technique in 150 patients from previous studies. The distribution of patients according to the GOLD stage of COPD was: 15 with stage 1; 40 with stage 2; 32 with stage 3; and 63 with stage 4. In GOLD stage 1, AaPo2 and V̇A/Q̇ mismatch were clearly abnormal; thereafter, hypoxemia, AaPo2, and V̇A/Q̇ imbalance increased, but the changes from GOLD stages 1–4 were modest. Postbronchodilator FEV1 was related to PaO2 ( r = 0.62) and PaCO2 ( r = −0.59) and to overall V̇A/Q̇ heterogeneity ( r = −0.48) ( P < 0.001 each). Pulmonary gas exchange abnormalities in COPD are related to FEV1 across the spectrum of severity. V̇A/Q̇ imbalance, predominantly perfusion heterogeneity, is disproportionately greater than airflow limitation in GOLD stage 1, suggesting that COPD initially involves the smallest airways, parenchyma, and pulmonary vessels with minimal spirometric disturbances. That progression of V̇A/Q̇ inequality with spirometric severity is modest may reflect pathogenic processes that reduce both local ventilation and blood flow in the same regions through airway and alveolar disease and capillary involvement.

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Severe Traumatic Brain Injury

10.2310/psych.2403 ◽

2018 ◽

Author(s):

Ryan Martin ◽

Lara Zimmermann ◽

Kee D. Kim ◽

Marike Zwienenberg ◽

Kiarash Shahlaie

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Intracranial Pressure ◽

Severe Traumatic Brain Injury ◽

Neurocritical Care ◽

Secondary Brain Injury ◽

Brain Oxygenation ◽

Barbiturate Coma ◽

Blast Traumatic Brain Injury ◽

Penetrating Traumatic Brain Injury

Traumatic brain injury remains a leading cause of death and disability worldwide. Patients with severe traumatic brain injury are best treated with a multidisciplinary, evidence-based, protocol-directed approach, which has been shown to decrease mortality and improve functional outcomes. Therapy is directed at the prevention of secondary brain injury through optimizing cerebral blood flow and the delivery of metabolic fuel (ie, oxygen and glucose). This is accomplished through the measurement and treatment of elevated intracranial pressure (ICP), the strict avoidance of hypotension and hypoxemia, and in some instances, surgical management. The treatment of elevated ICP is approached in a protocolized, tiered manner, with escalation of care occurring in the setting of refractory intracranial hypertension, culminating in either decompressive surgery or barbiturate coma. With such an approach, the rates of mortality secondary to traumatic brain injury are declining despite an increasing incidence of traumatic brain injury. This review contains 3 figures, 5 tables and 69 reference Key Words: blast traumatic brain injury, brain oxygenation, cerebral perfusion pressure, decompressive craniectomy, hyperosmolar therapy, intracranial pressure, neurocritical care, penetrating traumatic brain injury, severe traumatic brain injury

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