Panic disorder respiratory subtype: psychopathology and challenge tests - an update

Panic disorder (PD) pathophysiology is very heterogeneous, and the discrimination of distinct subtypes could be very useful. A subtype based on respiratory symptoms is known to constitute a specific subgroup. However, evidence to support the respiratory subtype (RS) as a distinct subgroup of PD with a well-defined phenotype remains controversial. Studies have focused on characterization of the RS based on symptoms and response to CO2. In this line, we described clinical and biological aspects focused on symptomatology and CO2 challenge tests in PD RS. The main symptoms that characterize RS are dyspnea (shortness of breath) and a choking sensation. Moreover, patients with the RS tended to be more responsive to CO2 challenge tests, which triggered more panic attacks in this subgroup. Future studies should focus on discriminating respiratory-related clusters and exploring psychophysiological and neuroimaging outcomes in order to provide robust evidence to confirm RS as a distinct subtype of PD.

Genetic analysis of a case with Pitt-Hopkins syndrome due to variant of TCF4 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a patient presenting with dysmorphism, intellectual disability, psychomotor delay and hypoplasia of corpus callosum by using next generation sequencing.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the patient and his family members and subjected to exome sequencing. Suspected variants were verified with Sanger sequencing.@*RESULTS@#The patient was found to carry a heterozygous c.1357delAinsGGA variant in exon 11 of the TCF4 gene, which was verified as de novo by Sanger sequencing. The variant may result in a truncated protein and affect its function.@*CONCLUSION@#The heterozygous c.1357delAinsGGA variant the TCF4 gene probably underlies the disease in the proband.

Genetic analysis of a rare case of Pitt-Hopkins syndrome due to partial deletion of TCF4 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child featuring delayed intellectual development.@*METHODS@#The child and his parents were subjected to conventional G-banding karyotyping and single nucleotide polymorphism array (SNP-array) analysis. Suspected copy number variations (CNVs) were verified in both parents.@*RESULTS@#No karyotypic abnormality was found with the child and his parents. SNP-array results for both parents were normal. The child was found to harbor a de novo 172 kb deletion at 18q21.2 with a physical position of 52 957 042-53 129 237. The deletion only involved one OMIM gene, namely TCF4, resulting in removal of its exons 6 to 8.@*CONCLUSION@#The SNP-array assay has facilitated with the diagnosis of this child. Deletion of 18q21.2 region probably accounts for the Pitt-Hopkins syndrome (PTHS) in this patient.

Cuidados de Enfermería en pacientes con ventilación mecánica invasiva en la Unidad de Cuidados Intensivos Pediátricos / Nursing Care in patients with invasive mechanical ventilation in the Pediatric Intensive Care Unit

La rehabilitación cardiometabólica es un programa multifactorial útil para el tratamiento de las principales patologías que tienen una relación directa con el sedentarismo, como patologías cardiovasculares, metabólicas y sus complicaciones. En mayo de 2004, durante la 57ª Asamblea Mundial de la Salud, se aprobó "La estrategia mundial de la Organización Mundial de la Salud (OMS) que aborda sobre el régimen alimentario, la actividad física y la salud" con la finalidad de disminuir la inactividad física, los malos hábitos de alimentación que de forma directa llevan al exceso de peso, y que están asociadas al riesgo cardiovascular (RCV), a las enfermedades cardiovasculares, a la diabetes mellitus (DM) del tipo 2 y a otras diferentes enfermedades degenerativas crónicas. En base a la cual se orienta a implementar una correcta prescripción del ejercicio tanto preventiva como terapéutica. Este protocolo de atención clínico-terapeútico va dirigido a profesionales de la salud para el control de enfermedades cardiometabólicas. Los profesionales sanitarios podrán ofertar una terapéutica integral a sus pacientes para dosificar el ejercicio de forma personalizada, a partir del estado de salud, conocimiento de patologías preexistentes, edad y condición física inicial del paciente, así como proporcionar un seguimiento mediante programas individualizados. Cuyo principal fin es mejorar la condición cardiovascular, evitar nuevas complicaciones y reducir la mortalidad.

Cardiometabolic rehabilitation is a multifactorial program useful for the treatment of the main pathologies that have a direct relationship with sedentary lifestyle, such as cardiovascular, metabolic pathologies and their complications. In May 2004, during the 57th World Health Assembly, "The World Strategy of the World Health Organization (WHO) that addresses the diet, physical activity and health" was approved in order to reduce the physical inactivity, poor eating habits that directly lead to excess weight, and that are associated with cardiovascular risk (CVR), cardiovascular diseases, diabetes mellitus type 2 and other different chronic degenerative diseases . Based on which it is oriented to implement a correct prescription of both preventive and therapeutic exercise.This protocol of clinical-therapeutic care is aimed at health professionals for the control of cardiometabolic diseases. Health professionals may offer a comprehensive therapy to their patients to dose the exercise in a personalized way, based on the state of health, knowledge of preexisting pathologies, age and initial physical condition of the patient, as well as providing follow-up through individualized programs. Whose main purpose is to improve the cardiovascular condition, avoid new complications and reduce mortality.

Dysfunctional breathing: what do we know? / Disfunção respiratória: o que sabemos?

ABSTRACT Dysfunctional breathing (DB) is a respiratory condition characterized by irregular breathing patterns that occur either in the absence of concurrent diseases or secondary to cardiopulmonary diseases. Although the primary symptom is often dyspnea or "air hunger", DB is also associated with nonrespiratory symptoms such as dizziness and palpitations. DB has been identified across all ages. Its prevalence among adults in primary care in the United Kingdom is approximately 9.5%. In addition, among individuals with asthma, a positive diagnosis of DB is found in a third of women and a fifth of men. Although DB has been investigated for decades, it remains poorly understood because of a paucity of high-quality clinical trials and validated outcome measures specific to this population. Accordingly, DB is often underdiagnosed or misdiagnosed, given the similarity of its associated symptoms (dyspnea, tachycardia, and dizziness) to those of other common cardiopulmonary diseases such as COPD and asthma. The high rates of misdiagnosis of DB suggest that health care professionals do not fully understand this condition and may therefore fail to provide patients with an appropriate treatment. Given the multifarious, psychophysiological nature of DB, a holistic, multidimensional assessment would seem the most appropriate way to enhance understanding and diagnostic accuracy. The present narrative review was developed as a means of summarizing the available evidence about DB, as well as improving understanding of the condition by researchers and practitioners.

RESUMO A disfunção respiratória (DR) é um quadro respiratório caracterizado por padrões respiratórios irregulares que ocorrem na ausência de doenças concomitantes ou secundariamente a doenças cardiopulmonares. Embora o principal sintoma seja frequentemente dispneia ou "fome por ar", a DR também está associada a sintomas não respiratórios, como vertigem e palpitações. A DR pode ser identificada em todas as idades. Sua prevalência entre adultos na atenção primária no Reino Unido é de aproximadamente 9,5%. Além disso, entre indivíduos com asma, um diagnóstico positivo de DR é encontrado em um terço das mulheres e um quinto dos homens. Embora a DR tenha sido investigada por décadas, ela permanece pouco compreendida devido a uma escassez de ensaios clínicos de alta qualidade e de variáveis de desfecho validadas especificamente para essa população. Assim, a DR é frequentemente subdiagnosticada ou diagnosticada incorretamente, devido à similaridade de seus sintomas associados (dispneia, taquicardia e vertigem) aos de outras doenças cardiopulmonares comuns, como DPOC e asma. As altas taxas de diagnóstico incorreto de DR sugerem que os profissionais de saúde não entendam completamente esse quadro e possam, portanto, não fornecer aos pacientes um tratamento adequado. Dada à natureza multifatorial e psicofisiológica da DR, uma avaliação holística e multidimensional parece ser a maneira mais apropriada de melhorar a compreensão e a precisão do diagnóstico. A presente revisão foi desenvolvida como um meio de resumir as evidências disponíveis sobre DB, bem como de melhorar a compreensão do quadro por pesquisadores e profissionais.

Recovery without Neurological Sequelae in Fulminant Cerebral Edema in Pediatric Encephalitis with Human Herpesvirus Type 6 / 대한소아신경학회지

Viral encephalitis can lead to serious neurological sequelae and death among younger children. It is also known that the mortality rate in encephalitis with cerebral edema or transtentorial brain herniation is higher. A 4-year-old boy visited our emergency department exhibiting mental change. The patient had a high fever for four and a whole-body rash for three days prior to his visit. He had displayed irritable symptoms and been vomiting for six hours before his visit, accompanied by seizure. After 13 hours of admission, the patient's right pupil became fixed and fully dilated, and the left pupil also became fixed and fully dilated within 30 minutes. Brain computed tomography (CT) was performed immediately, and severe brain swelling with transtentorial brain herniation was found. The mannitol dose was increased and dexamethasone was also added. Hyperventilation was performed through intubation to reach PaCO₂ levels of 25 to 30mmHg. Fifteen hours later, pupillary reflex was observed and the cerebral edema and transtentorial brain herniation was found to be improving in follow-up brain CT. He was transferred to a general ward after 11 days and discharged on the thirteenth hospital day without any neurological sequelae. Human herpesvirus type 6 (HHV-6) was detected in the serological polymerase chain reaction (PCR) examination.

Transient Abnormalities on Magnetic Resonance Imaging after Absence Seizures / 대한소아신경학회지

Magnetic resonance imaging (MRI) is recommended for patients with epileptic seizures to rule out an underlying focal lesion. However, abnormalities in idiopathic generalized epilepsy, including childhood absence epilepsy, cannot usually be identified using brain imaging modalities such as MRI. Peri-ictal MRI abnormalities have been most commonly reported secondary to status epilepticus and are rarely observed in patients with focal seizures and generalized tonic-clonic seizures. Transient peri-ictal MRI abnormalities in absence epilepsy are extremely rare. A five-year-old girl presented with a three-day history of absence seizures that persisted despite continued treatment with sodium valproate. Electroencephalography showed bursts of generalized 3-Hz spike-and-wave discharges, during and after hyperventilation. Abnormal cortex thickening in the left perisylvian region was detected on T2-weighted brain MRI, and cortical dysplasia or a tumor was suspected. The patient started treatment with lamotrigine and was seizure-free after one month. The abnormal MRI lesion was completely resolved at the two-month follow-up. We report on a patient with childhood absence epilepsy and reversible brain MRI abnormalities in the perisylvian region. To our knowledge, this is the first report of transient MRI abnormalities after absence seizures. Transient peri-ictal MRI abnormalities should be considered for differential diagnosis in patients with absence seizures and a focal abnormality on brain MRI.

A Case of Aggravation of Thyroid Goiter after Treatment with PD-1 Inhibitor for Breast Cancer in Patients with Underlying Hashimoto's Thyroiditis

Anti-programmed cell death-1 (PD-1) humanized monoclonal antibody inhibits PD-1 activity by binding to the PD-1 receptor on T-cells and blocking PD-1 ligands and induces immune tolerance of cancer cells. It has been widely used for various kinds of cancer treatment. However, many immune-related adverse events (irAEs) have been reported because it modulates our immune system. In this case study, we reported a case of 42-year-old woman with Hashimoto's thyroiditis who showed rapid aggravation of thyroid goiter and acute hyperventilation syndrome after treatment with PD-1 inhibitor as a neoadjuvant chemotherapy for breast cancer.

Prevalence of Operation Room-Related Syncope and Presyncope among Medical Students / 의학교육논단

Attending the operation room is an essential part of surgical clerkships. Syncope or presyncopal attacks in the operation room may negatively affect students' learning and career development. This study set out to identify the prevalence of syncope and presyncopal attacks in the operation room during medical students' surgical clerkships. Data from 420 medical students (303 men and 117 women) in their 3rd year of clerkship were collected between 2014 and 2017. An anonymous questionnaire was distributed to assess the prevalence and degree of syncope and presyncopal symptoms. A total of 27% of the respondents had experienced syncope or presyncopal symptoms, 49.6% of the female students and 18.8% of the male students (p < 0.001). Fifty students (43.5%) had been attending as observers at the time of the syncopal attack, while 65 students (56.5%) had been participating as assistants. Thirty-four students (29.6%) had recently eaten at the time of the syncopal attack, while 81 students (70.4%) had not recently eaten. Prodromal symptoms included the urge to sit down (21.2%), sweating (19.3%), nausea (16.9%), a feeling of warmth (13.3%), darkened vision (12.6%), yawning (11.7%), palpitation (11.0%), ear fullness (10.2%), black spots in one's vision (7.6%), and hyperventilation (7.1%). This study showed the prevalence of syncope and presyncopal symptoms in the operation room during surgical clerkships. For students' safety and effective clerkship learning, thorough proactive education on syncopal attacks is required.

Moyamoya disease in a 3-year-old boy presenting with a focal motor seizure provoked by hyperventilation

A previously healthy, 3-year-old boy presented to the emergency department with an afebrile focal motor seizure. He was found crying and having a seizure 30 minutes earlier. During this seizure, he was jerking his head and right extremities. Subsequent magnetic resonance imaging showed acute infarction in the bilateral frontal lobes, chiefly in the left. After hospitalization, conventional angiography demonstrated bilateral stenosis of the distal internal carotid arteries with development of lenticulostriate collaterals, which confirmed the diagnosis of moyamoya disease. It is vital to recognize focal motor seizures and situations related to hyperventilation in children with a seizure, which imply a structural lesion and a provoked cerebral ischemia in preexisting moyamoya disease, respectively.

Electroencephalographic Abnormalities in the Screening for Pilot Applicants in Korea

BACKGROUND AND PURPOSE: Electroencephalography (EEG) is often used as a screening tool for selecting pilots despite controversy regarding its contribution to aviation safety. We investigated EEG abnormalities in Korean commercial pilot applicants in order to identify the usefulness of EEG screening in this population. METHODS: We retrospectively analyzed the EEG results of 740 unselected pilot applicants who underwent waking EEG at Inha University Hospital from January 2013 to May 2017. EEG recording was performed for 30 minutes, which included 3 minutes of hyperventilation and intermittent photic stimulation. RESULTS: The pilot applicants were predominantly male (95.3%) and had a mean age of 27.8 years (range: 16–40 years). Nine of them (1.2%) exhibited EEG abnormalities; the most common abnormality (six applicants) was a small amount of generalized irregular slow activities, while the other three applicants (0.4%) exhibited epileptiform discharges, with two showing generalized spike-and-wave complexes and one showing a few spike-and-wave complexes in the left frontotemporal area. The two applicants with generalized spike-and-wave complexes were found to have experienced clinical seizures by a neurologist during detailed history-taking. CONCLUSIONS: This study found that 2 of 740 pilot applicants (0.3%) were diagnosed with epilepsy by routine EEG screening in an unselected population. Considering the low predictive value of EEG without the relevant clinical history in an unselected healthy young population, our findings raise questions regarding the cost-effectiveness of the current EEG screening protocol applied to pilot applicants. We suggest that a more-targeted and standardized EEG screening approach be applied to pilot applicants with epilepsy risk factors or a seizure history as determined by thorough medical history-taking.

Improvement of Peak Cough Flow After the Application of a Mechanical In-exsufflator in Patients With Neuromuscular Disease and Pneumonia: A Pilot Study

OBJECTIVE: To investigate and demonstrate persistent increase of peak cough flow after mechanical in-exsufflator application, in patients with neuromuscular diseases and pneumonia. METHODS: A mechanical in-exsufflator was applied with patients in an upright or semi-upright sitting position (pressure setting, +40 and −40 cmH2O; in-exsufflation times, 2–3 and 1–2 seconds, respectively). Patients underwent five cycles, with 20–30 second intervals to prevent hyperventilation. Peak cough flow without and with assistive maneuvers, was evaluated before, and 15 and 45 minutes after mechanical in-exsufflator application. RESULTS: Peak cough flow was 92.6 L/min at baseline, and 100.4 and 100.7 L/min at 15 and 45 minutes after mechanical in-exsufflator application, respectively. Assisted peak cough flow at baseline, 15 minutes, and 45 minutes after mechanical in-exsufflator application was 170.7, 179.3, and 184.1 L/min, respectively. While peak cough flow and assisted peak cough flow increased significantly at 15 minutes after mechanical in-exsufflator application compared with baseline (p=0.030 and p=0.016), no statistical difference was observed between 15 and 45 minutes. CONCLUSION: Increased peak cough flow after mechanical in-exsufflator application persists for at least 45 minutes.

Paroxysmal Kinesigenic Dyskinesia as the Presenting and Only Manifestation of Multiple Sclerosis after Eighteen Months of Follow-Up

Other than tremor, movement disorders are uncommon in multiple sclerosis. Among these uncommon clinical manifestations, paroxysmal kinesigenic dyskinesia is the most frequently reported. It is characterized by episodic attacks of involuntary movements that are induced by repetitive or sudden movements, startling noise or hyperventilation. The diagnosis is essentially clinical and based on a good observation of the attacks. It is very easy to misdiagnose it. We describe the case of a young female patient who presented paroxysmal kinesigenic dyskinesia as the first and only clinical manifestation of multiple sclerosis, with no recurrence of attacks nor any other neurologic symptom after eighteen months of follow-up.

Decrease in spectral entropy by low tidal volume ventilation-associated severe hypercapnia: a case report / 대한마취과학회지

Severe hypercapnia can be predicted by a decrease in cerebral electrical activity. The authors describe a sudden decrease in spectral entropy due to severe hypercapnia-induced respiratory acidosis in a patient with chronic pulmonary obstructive disease during lung resection. After two and a half hours of low tidal volume ventilation in the lateral position, the state entropy suddenly dropped from 45 to 7, without any changes in the effect-site concentration of propofol, end-tidal carbon dioxide (CO₂) tension, oxygen saturation, or arterial pressure. However, arterial blood gas analysis showed severe respiratory acidosis (pH 7.01, PaCO₂ 115 mmHg and PaO₂ 246 mmHg with FIO₂ of 0.5). Immediate hyperventilation improved the state entropy and acid-base balance. Electroencephalography-based spectral entropy can detect severe hypercapnia in chronic pulmonary obstructive disease patients with a large arterial to end-tidal CO2 difference due to prolonged hypoventilation during thoracic surgery.

Decrease in spectral entropy by low tidal volume ventilation-associated severe hypercapnia: a case report / 대한마취과학회지

Severe hypercapnia can be predicted by a decrease in cerebral electrical activity. The authors describe a sudden decrease in spectral entropy due to severe hypercapnia-induced respiratory acidosis in a patient with chronic pulmonary obstructive disease during lung resection. After two and a half hours of low tidal volume ventilation in the lateral position, the state entropy suddenly dropped from 45 to 7, without any changes in the effect-site concentration of propofol, end-tidal carbon dioxide (CO₂) tension, oxygen saturation, or arterial pressure. However, arterial blood gas analysis showed severe respiratory acidosis (pH 7.01, PaCO₂ 115 mmHg and PaO₂ 246 mmHg with FIO₂ of 0.5). Immediate hyperventilation improved the state entropy and acid-base balance. Electroencephalography-based spectral entropy can detect severe hypercapnia in chronic pulmonary obstructive disease patients with a large arterial to end-tidal CO2 difference due to prolonged hypoventilation during thoracic surgery.

A Case of Lactate Containing Peritoneal Dialysis Solution Induced Lactic Acidosis Corrected by Changing to Hemodialysis / 고신대학교의과대학학술지

Elevated lactate levels are associated with acute illnesses, and the mortality is high. Here, we report a case of lactate-containing peritoneal dialysis (PD) solution inducing lactic acidosis corrected by changing to hemodialysis (HD). This 70-year-old female patient was treated with PD 8 months previously for end-stage renal disease caused by diabetes mellitus. She was admitted complaining of general weakness. Initial lactate level was 22.1 mg/dL and increased to 62.4 mg/dL showing high anion gap metabolic acidosis and compensatory hyperventilation. There are no definite causes of lactic acidosis besides the use of PD solutions containing a lactate component. The patient's lactate level was decreased after temporarily changing the dialysis modality to HD. Her lactate level was increased again after restarting PD, and decreased to normal after restarting HD. We report this case because physicians should consider lactate-containing PD solution as a possible cause of lactic acidosis.

Nonspecific Bronchoprovocation Test / 결핵및호흡기질환

Bronchial asthma is a disease characterized by the condition of airway hyper-responsiveness, which serves to produce narrowing of the airway secondary to airway inflammation and/or various spasm-inducing stimulus. Nonspecific bronchoprovocation testing is an important method implemented for the purpose of diagnosing asthma; this test measures the actual degree of airway hyper-responsiveness and utilizes direct and indirect bronchoprovocation testing. Direct bronchoprovocation testing using methacholine or histamine may have superior sensitivity as these substances directly stimulate the airway smooth muscle cells. On the other hand, this method also engenders the specific disadvantage of relatively low specificity. Indirect bronchoprovocation testing using mannitol, exercise, hypertonic saline, adenosine and hyperventilation serves to produce reactions in the airway smooth muscle cells by liberating mediators with stimulation of airway inflammatory cells. Therefore, this method has the advantage of high specificity and also demonstrates relatively low sensitivity. Direct and indirect testing both call for very precise descriptions of very specific measurement conditions. In addition, it has become evident that challenge testing utilizing each of the various bronchoconstrictor stimuli requires distinct and specific protocols. It is therefore important that the clinician understand the mechanism by which the most commonly used bronchoprovocation testing works. It is important that the clinician understand the mechanism of action in the testing, whether direct stimuli (methacholine) or indirect stimuli (mannitol, exercise) is implemented, when the testing is performed and the results interpreted.

Adverse reactions in allogeneic blood donors: a tertiary care experience from a developing country

Objectives: Fragmented blood transfusion services along with an unmotivated blood donation culture often leads to blood shortage. Donor retention is crucial to meet the increasing blood demand, and adverse donor reactions have a negative impact on donor return. The aim of this study was to estimate adverse donor reactions and identify any demographic association

Methods: We conducted a prospective study between January 2011 and December 2013. A total of 41,759 healthy donors were enrolled. Professionally trained donor attendants drew blood and all donors were observed during and following donation for possible adverse events for 20 minutes. Blood donors were asked to report if they suffered from any delayed adverse consequences

Results: Out of 41,759 blood donors, 537 [1.3%] experienced adverse reactions. The incidence was one in every 78 donations. The mean age of donors who experienced adverse events was 26.0 +/- 6.8 years, and all were male. Out of 537 donors, 429 [80%] developed vasovagal reaction [VVR], 133 [25%] had nausea, 63 [12%] fainted, 35 [6%] developed hyperventilation, 9 [2%] had delayed syncope, and 9 [2%] developed hematoma. Arterial prick, nerve injury, cardiac arrest, and seizures were not observed. Donors aged less than < 30 years and weighing <70 kg were significantly associated with VVR, hyperventilation, and nausea [p < 0.005]. Undergraduates and Urdu speaking donors also had a significant association with fainting and nausea, respectively [p < 0.05]

Conclusion: The prevalence of adverse events was low at our tertiary center. A VVR was the predominant adverse reaction and was associated with age and weight. Our study highlights the importance of these parameters in the donation process. A well-trained and experienced phlebotomist and pre-evaluation counseling of blood donors could further minimize the adverse reactions

Central hyperventilation syndrome due to massive pneumocephalus after endoscopic third ventriculostomy: a case report / 대한마취과학회지

Pneumocephalus is common after brain surgeries, but usually is not substantial enough to cause serious complications. We recently encountered a case of post-operative tachypnea after an endoscopic 3rd ventriculostomy. At first, we thought that the hyperventilation was the result of residual paralysis after emergence from anesthesia, but during further evaluation we found a massive pneumocephalus. In such unusual post-operative situations, physicians should consider surgery-related complications as the possible cause as well, along with the anesthetic factors.

Acute but not chronic metabolic acidosis potentiates the acetylcholine-induced reduction in blood pressure: an endothelium-dependent effect

Metabolic acidosis has profound effects on vascular tone. This study investigated the in vivo effects of acute metabolic acidosis (AMA) and chronic metabolic acidosis (CMA) on hemodynamic parameters and endothelial function. CMA was induced by ad libitum intake of 1% NH4Cl for 7 days, and AMA was induced by a 3-h infusion of 6 M NH4Cl (1 mL/kg, diluted 1:10). Phenylephrine (Phe) and acetylcholine (Ach) dose-response curves were performed by venous infusion with simultaneous venous and arterial blood pressure monitoring. Plasma nitrite/nitrate (NOx) was measured by chemiluminescence. The CMA group had a blood pH of 7.15±0.03, which was associated with reduced bicarbonate (13.8±0.98 mmol/L) and no change in the partial pressure of arterial carbon dioxide (PaCO2). The AMA group had a pH of 7.20±0.01, which was associated with decreases in bicarbonate (10.8±0.54 mmol/L) and PaCO2 (47.8±2.54 to 23.2±0.74 mmHg) and accompanied by hyperventilation. Phe or ACh infusion did not affect arterial or venous blood pressure in the CMA group. However, the ACh infusion decreased the arterial blood pressure (ΔBP: -28.0±2.35 mm Hg [AMA] to -4.5±2.89 mmHg [control]) in the AMA group. Plasma NOx was normal after CMA but increased after AMA (25.3±0.88 to 31.3±0.54 μM). These results indicate that AMA, but not CMA, potentiated the Ach-induced decrease in blood pressure and led to an increase in plasma NOx, reinforcing the effect of pH imbalance on vascular tone and blood pressure control.