• Aneurysmal subarachnoid hemorrhage
• Carbon dioxide
• Neurological outcomes
• Restricted cubic spline

• carbon-based electrocatalyst
• in situ engineering
• in vivo electrochemistry
• microsensor
• neurochemical sensing

• Carbon Fiber/chemistry
• Carbon/chemistry
• Electrochemical Techniques/methods
• Polymers/chemistry
• Animals
• Indoles/chemistry
• Microelectrodes
• Ascorbic Acid/chemistry
• Oxygen/chemistry
• Oxygen/metabolism
• Zeolites/chemistry
• Imidazoles/chemistry
• Carbon Dioxide/chemistry

• 22174162 the National Natural Science Foundation of China

• resting PCO 2
• cerebrovascular reactivity
• intracranial atherosclerotic disease
• moyamoya vasculopathy
• steno-occlusive disease

• Child
• Humans
• Hypotension
• Hypoxia/etiology
• Hypoxia/therapy
• Infant
• Infant, Newborn
• Operating Rooms

Carbon dioxide is a common gas in the air which has been widely used in medical treatment. A carbon dioxide molecule consists of two oxygen atoms and one carbon atom through a covalent bond. In the body, carbon dioxide reacts with water to produce carbonic acid. In healthy people, carbon dioxide is maintained within a narrow range (35–45 mmHg) by physiological mechanisms. The role of hypocapnia (partial pressure of carbon dioxide < 35 mmHg) and hypercapnia (partial pressure of carbon dioxide > 45 mmHg) in the nervous system is intricate. Past researches mainly focus on the effect of hypocapnia to nerve protection. Nevertheless, Hypercapnia seems to play an important role in neuroprotection. The mechanisms of hypocapnia and hypercapnia in the nervous system deserve our attention. The purpose of this review is to summarize the effect of hypocapnia and hypercapnia in stroke and traumatic brain injury.

• carbon dioxide
• hypercapnia
• hypocapnia
• intracranial pressure
• nervous system
• neuroprotection
• stroke
• traumatic brain injury

Perioperative stroke is a rare but devastating complication. The risk factors for massive cerebral stroke in surgical patients include older age, male sex, prior cerebrovascular disease, hypertension, renal failure, smoking, diabetes mellitus, and atrial fibrillation.

We describe two cases of perioperative massive cerebral stroke following thoracic surgery and one case following bronchoscopy. Neurologic symptoms, including changes in mental status and hemiplegia, occurred within 10 h after surgery in the three patients. All three patients died after the surgery.

Perioperative massive cerebral stroke may be more likely to occur in thoracic surgical patients if there are pre-existing factors including previous stroke, hypotension, and hypoxemia. Sufficient pain control after surgery and timely neurology consultation and management are helpful for the diagnosis and control of stroke in high-risk patients.

• Perioperative
• Massive cerebral stroke
• Thoracic surgery
• Anesthesia
• Literature review
• Case report

• cerebrovascular reactivity
• high school
• neurovascular coupling
• transcranial Doppler

• Laryngologic surgery
• airway management
• apneic oxygenation
• high-flow nasal cannula
• high-flow nasal oxygen
• transnasal humidified rapid-insufflation ventilatory exchange

Hyperventilation is commonly used in neurological patients to decrease elevated intracranial pressure (ICP) or relax a tense brain. However, the potentially deleterious effects of hyperventilation may limit its clinical application. The aim of this review is to summarize the physiological and outcome evidence related to hyperventilation in neurological patients.

A CO₂ pneumoperitoneum during a laparoscopic procedure causes violent hemodynamic changes. However, the remifentanil required to inhibit the cardiovascular response to a CO₂ pneumoperitoneum combined with propofol remains unknown. Moreover, the sex of the patient may influence the response to opioids, which can affect this requirement. The main objective of this study was to compare the required median effective concentration (EC₅₀) of remifentanil for inhibiting the cardiovascular response to a CO₂ pneumoperitoneum between female and male patients during propofol anesthesia.

The current study is an up-and-down sequential allocation trial. Forty-six patients with American Society of Anesthesiologists physical status I or II, a body mass index 18 to 30 kg/m², aged 20 to 60 years, and scheduled for laparoscopic surgery were enrolled. Induction of anesthesia was performed by target-controlled infusion. The effective effect-site concentration (Ce) of propofol was 4 μg/ml. The Ce of remifentanil was initially 4 ng/ml and then adjusted to a predetermined level after I-gel laryngeal mask airway insertion. The Ce of remifentanil for each patient was determined by the response of the previous patient using the modified Dixon “up-and-down” method. The first patient received remifentanil at 5.0 ng/ml Ce, and the step size between patients was 0.5 ng/ml.

Patients characteristics including age, body mass index, American Society of Anesthesiologists physical status, type of surgery and surgery duration, were comparable between male and female patients. The EC₅₀ of remifentanil required to inhibit the response to a CO₂ pneumoperitoneum based on the Dixon “up-and-down” method in women (4.17 ± 0.38 ng/ml) was significantly lower than that in men (5.00 ± 0.52 ng/ml) during propofol anesthesia (P = 0.01).

The EC₅₀ of remifentanil required to inhibit the response to a CO₂ pneumoperitoneum was lower in women than in men during propofol anesthesia.

The study was registered at http://www.chictr.org.cn (ChiCTR-IOR-17011906, 8th, July, 2017).

• Anesthesia
• Pharmacology
• Pneumoperitoneum
• Remifentanil

• Intracranial pressure
• Laparoscopy
• Optic nerve
• Pneumoperitoneum
• Trendelenburg
• Ultrasound

• Head-Down Tilt
• Humans
• Intracranial Hypertension
• Intracranial Pressure
• Laparoscopy
• Male
• Optic Nerve/diagnostic imaging

• Adult
• Anesthesia, General
• Anesthesiology
• Humans
• Insufflation
• Oxygen
• Oxygen Inhalation Therapy

Lung protective mechanical ventilation with limited peak inspiratory pressure has been shown to affect cardiac output in patients with ARDS. However, little is known about the impact of lung protective mechanical ventilation on regional perfusion, especially when associated with moderate permissive respiratory acidosis. We hypothesized that lung protective mechanical ventilation with limited peak inspiratory pressure and moderate respiratory acidosis results in an increased cardiac output but unequal distribution of blood flow to the different organs of pigs with oleic-acid induced ARDS.

Twelve pigs were enrolled, 3 died during instrumentation and induction of lung injury. Thus, 9 animals received pressure controlled mechanical ventilation with a PEEP of 5 cmH₂O and limited peak inspiratory pressure (17 ± 4 cmH₂O) versus increased peak inspiratory pressure (23 ± 6 cmH₂O) in a crossover-randomized design and were analyzed. The sequence of limited versus increased peak inspiratory pressure was randomized using sealed envelopes. Systemic and regional hemodynamics were determined by double indicator dilution technique and colored microspheres, respectively. The paired student t–test and the Wilcoxon test were used to compare normally and not normally distributed data, respectively.

Mechanical ventilation with limited inspiratory pressure resulted in moderate hypercapnia and respiratory acidosis (PaCO₂ 71 ± 12 vs. 46 ± 9 mmHg, and pH 7.27 ± 0.05 vs. 7.38 ± 0.04, p < 0.001, respectively), increased cardiac output (140 ± 32 vs. 110 ± 22 ml/min/kg, p<0.05) and regional blood flow in the myocardium, brain and spinal cord, adrenal and thyroid glands, the mucosal layers of the esophagus and jejunum, the muscularis layers of the esophagus and duodenum, and the gall and urinary bladders. Perfusion of kidneys, pancreas, spleen, hepatic arterial bed, and the mucosal and muscularis blood flow to the other evaluated intestinal regions remained unchanged.

In this porcine model of ARDS mechanical ventilation with limited peak inspiratory pressure resulting in moderate respiratory acidosis was associated with an increase in cardiac output. However, the better systemic blood flow was not uniformly directed to the different organs. This observation may be of clinical interest in patients, e.g. with cardiac, renal and cerebral pathologies.

The online version of this article (10.1186/s12871-017-0439-7) contains supplementary material, which is available to authorized users.

• Cardiac output
• Hemodynamics
• Lung protective ventilation
• Permissive hypercapnia
• Regional blood flow
• Respiratory distress syndrome

• Capnography
• Classification
• Detection
• Feature extraction
• Prediction
• Screening

• Aged
• Aged, 80 and over
• Aging/physiology
• Anesthesia
• Cardiovascular System
• Chronic Disease
• Cognition Disorders/epidemiology
• Cognition Disorders/etiology
• Cognition Disorders/psychology
• Delirium/epidemiology
• Delirium/etiology
• Delirium/psychology
• Female
• Geriatric Assessment
• Geriatrics
• Humans
• Length of Stay
• Male
• Middle Aged
• Nervous System
• Postoperative Complications/epidemiology
• Postoperative Complications/psychology
• Respiratory System
• Rewarming
• Risk
• Risk Factors

• Aged
• Anesthetics, Intravenous/pharmacology
• Brain/metabolism
• Cerebrovascular Circulation
• Female
• Humans
• Hypercapnia/metabolism
• Hypertension/metabolism
• Lung/surgery
• Male
• Middle Aged
• Oxygen/metabolism
• Propofol/pharmacology
• Prospective Studies
• Respiration, Artificial

• Adult
• Aged
• Anesthesia
• Blood Substitutes/therapeutic use
• Blood Volume/physiology
• Child
• Child, Preschool
• Emergency Medical Services
• Humans
• Infant
• Middle Aged
• Pain Management
• Respiration, Artificial
• Respiratory Mechanics/physiology
• Thoracic Injuries/etiology
• Thoracic Injuries/mortality
• Thoracic Injuries/surgery
• Thoracic Injuries/therapy
• Wounds, Nonpenetrating/etiology
• Wounds, Nonpenetrating/therapy

The objective was to study the effects of a lung recruitment procedure by stepwise increases of mean airway pressure upon organ blood flow and hemodynamics during high-frequency oscillatory ventilation (HFOV) versus pressure-controlled ventilation (PCV) in experimental lung injury.

Lung damage was induced by repeated lung lavages in seven anesthetized pigs (23–26 kg). In randomized order, HFOV and PCV were performed with a fixed sequence of mean airway pressure increases (20, 25, and 30 mbar every 30 minutes). The transpulmonary pressure, systemic hemodynamics, intracranial pressure, cerebral perfusion pressure, organ blood flow (fluorescent microspheres), arterial and mixed venous blood gases, and calculated pulmonary shunt were determined at each mean airway pressure setting.

The transpulmonary pressure increased during lung recruitment (HFOV, from 15 ± 3 mbar to 22 ± 2 mbar, P < 0.05; PCV, from 15 ± 3 mbar to 23 ± 2 mbar, P < 0.05), and high airway pressures resulted in elevated left ventricular end-diastolic pressure (HFOV, from 3 ± 1 mmHg to 6 ± 3 mmHg, P < 0.05; PCV, from 2 ± 1 mmHg to 7 ± 3 mmHg, P < 0.05), pulmonary artery occlusion pressure (HFOV, from 12 ± 2 mmHg to 16 ± 2 mmHg, P < 0.05; PCV, from 13 ± 2 mmHg to 15 ± 2 mmHg, P < 0.05), and intracranial pressure (HFOV, from 14 ± 2 mmHg to 16 ± 2 mmHg, P < 0.05; PCV, from 15 ± 3 mmHg to 17 ± 2 mmHg, P < 0.05). Simultaneously, the mean arterial pressure (HFOV, from 89 ± 7 mmHg to 79 ± 9 mmHg, P < 0.05; PCV, from 91 ± 8 mmHg to 81 ± 8 mmHg, P < 0.05), cardiac output (HFOV, from 3.9 ± 0.4 l/minute to 3.5 ± 0.3 l/minute, P < 0.05; PCV, from 3.8 ± 0.6 l/minute to 3.4 ± 0.3 l/minute, P < 0.05), and stroke volume (HFOV, from 32 ± 7 ml to 28 ± 5 ml, P < 0.05; PCV, from 31 ± 2 ml to 26 ± 4 ml, P < 0.05) decreased. Blood flows to the heart, brain, kidneys and jejunum were maintained. Oxygenation improved and the pulmonary shunt fraction decreased below 10% (HFOV, P < 0.05; PCV, P < 0.05). We detected no differences between HFOV and PCV at comparable transpulmonary pressures.

A typical recruitment procedure at the initiation of HFOV improved oxygenation but also decreased systemic hemodynamics at high transpulmonary pressures when no changes of vasoactive drugs and fluid management were performed. Blood flow to the organs was not affected during lung recruitment. These effects were independent of the ventilator mode applied.

• Acute Disease
• Animals
• Blood Gas Analysis
• High-Frequency Ventilation/methods
• Lung/blood supply
• Lung/physiology
• Lung Diseases/physiopathology
• Lung Injury
• Swine