Arterial Blood Gases in Normal Subjects at 2240 Meters Above Sea Level: Impact of Age, Gender, and Body Mass Index

ABSTRACT Background The values of arterial blood gases (ABG) change with altitude above sea level; empirical verification is essential because ventilatory acclimatization varies with ethnicity and a population's adaptation. Objective The aim of the study was to describe ABG in a healthy population residing at 2,240 meters above sea level, to identify the mean level of alveolar ventilation (PaCO2), and to know whether a progressive increase in PaCO2 occurs with age and the impact of increasing body mass index (BMI). Methods We conducted a cross-sectional study in a referral center for respiratory diseases in Mexico City. Associations among variables with correlation coefficient and regression models of PaO2, SaO2, and P(A-a)O2 as dependent variables as a function of age, BMI, minute ventilation, or breathing frequency were explored. Results Two hundred and seventeen healthy subjects were evaluated with a mean age of 40 ± 15 years, mean of the PaO2 was 71 ± 6 mmHg, SaO2 94% ± 1.6%, PaCO2 30.2 ± 3.4 mmHg, HCO3 20 ± 2 mmol/L, BE-2.9 ± 1.9 mmol/L, and the value of pH was 7.43 ± 0.02. In a linear regression, the main results were PaO2 = 77.5-0.16*age (p < 0.0001) and with aging P(A-a)O2 tended to increase 0.12 mmHg/year. PaCO2 in women increased with age by 0.075 mmHg/year (p = 0.0012, PaCO2 =26.3 + 0.075*age). SaO2 and PaO2 decreased significantly in women with higher BMI 0.14% and 0.52 mmHg per kg/m2, (p = 0.004 and 0.002 respectively). Conclusion Mean PaCO2 was 30.7 mmHg, implying a mean alveolar ventilation of around 30% above that at sea level.

O Uso de um Ventilador Mecânico Portátil na Ressuscitação Cardiopulmonar é Viável, Melhora os Parâmetros Respiratórios e Previne a Redução da Complacência Pulmonar Dinâmica / Use of a Portable Mechanical Ventilator during Cardiopulmonary Resuscitation is Feasible, Improves Respiratory Parameters, and Prevents the Decrease of Dynamic Lung Compliance

Resumo Fundamentos Para ventilação prática e protetora durante a ressuscitação cardiopulmonar (RCP), desenvolveu-se um ventilador mecânico (VLP2000E) de 150 gramas que limita o pico de pressão inspiratória (PPI) durante ventilação e compressões torácicas simultâneas. Objetivos Avaliar a viabilidade da ventilação com VLP2000E durante RCP e comparar os parâmetros monitorados versus ventilação com bolsa-válvula. Métodos Estudo experimental randomizado com 10 porcos intubados por grupo. Após sete minutos de fibrilação ventricular, iniciaram-se ciclos de RCP de 2 minutos. Todos os animais foram ventilados com VLP2000E após o retorno da circulação espontânea (RCE). Resultados Os grupos bolsa-válvula e VLP2000E apresentaram taxa de RCE (60% vs. 50%, respectivamente) e saturação arterial de oxigênio similares na maioria dos ciclos de RCP, volume corrente basal diferente [0,764 (0,068) vs. 0,591 (0,123) L, p = 0,0309, respectivamente] e, em 14 ciclos, diferentes PPI [52 (9) vs. 39 (5) cm H2O, respectivamente], volume corrente [0,635 (0,172) vs. 0,306 (0,129) L], ETCO2 [14 (8) vs. 27 (9) mm Hg], e pico de fluxo inspiratório [0,878 (0,234) vs. 0,533 (0,105) L/s], todos p < 0,0001. A complacência pulmonar dinâmica (≥ 0,025 L/cm H2O) diminuiu após o RCE no grupo bolsa-válvula, mas se manteve no grupo VLP2000E [ 0,019 (0,006) vs. 0,024 (0,008) L/cm H2O, p = 0,0003]. Conclusões Ventilação com VLP2000E durante RCP é viável e equivalente a ventilação com bolsa-válvula quanto à taxa de RCE e saturação arterial de oxigênio. Esse ventilador produz melhores parâmetros respiratórios, com pressão das vias aéreas e volume corrente menores. Ventilação com VLP2000E também previne a redução significante da complacência pulmonar dinâmica observada após ventilação com bolsa-válvula. Seria interessante realizar mais estudos pré-clínicos para confirmar esses resultados.

Abstract Background For practical and protective ventilation during cardiopulmonary resuscitation (CPR), a 150-grams mechanical ventilator (VLP2000E) that limits peak inspiratory pressure (PIP) during simultaneous ventilation with chest compressions was developed. Objectives To evaluate the feasibility of VLP2000E ventilation during CPR and to compare monitored parameters versus bag-valve ventilation. Methods A randomized experimental study with 10 intubated pigs per group. After seven minutes of ventricular fibrillation, 2-minute CPR cycles were delivered. All animals were placed on VLP2000E after achieving return of spontaneous circulation (ROSC). Results Bag-valve and VLP2000E groups had similar ROSC rate (60% vs. 50%, respectively) and arterial oxygen saturation in most CPR cycles, different baseline tidal volume [0.764 (0.068) vs. 0.591 (0.123) L, p = 0.0309, respectively] and, in 14 cycles, different PIP [52 (9) vs. 39 (5) cm H2O, respectively], tidal volume [0.635 (0.172) vs. 0.306 (0.129) L], ETCO2[14 (8) vs. 27 (9) mm Hg], and peak inspiratory flow [0.878 (0.234) vs. 0.533 (0.105) L/s], all p < 0.0001. Dynamic lung compliance (≥ 0.025 L/cm H2O) decreased after ROSC in bag-valve group but was maintained in VLP2000E group [0.019 (0.006) vs. 0.024 (0.008) L/cm H2O, p = 0.0003]. Conclusions VLP2000E ventilation during CPR is feasible and equivalent to bag-valve ventilation in ROSC rate and arterial oxygen saturation. It produces better respiratory parameters, with lower airway pressure and tidal volume. VLP2000E ventilation also prevents the significant decrease of dynamic lung compliance observed after bag-valve ventilation. Further preclinical studies confirming these findings would be interesting.

Late Onset Subacute Profound Biotinidase Deficiency Caused by a Novel Homozygous Variant c.466-3T>G in the BTD Gene

Biotinidase defciency (BD) is an autosomal recessive disorder caused by bi-allelic mutation in the BTD gene. Clinical manifestations in BD mainly depends on residual biotinidase enzyme activity, although there are some exceptions. Broadly BD disorders are classifed as profound BD and partial BD. Further profound BD can be early onset, late onset, and sometimes may be asymptomatic. Clinically late-onset profound BD can present with spectrum of manifestations ranging from single organ to multiple organ involvement, typically afecting function of brain, eye, ear, and skin. Here, a frst-born child to consanguineous parents with late-onset profound BD presenting with hyperventilation secondary to lactic acidosis, hypotonia, evolving spasticity, and abnormal neuroimaging fndings caused by novel homozygous variant, c.466-3T>G in the BTD gene is reported.

Actualización en el tratamiento del síndrome de hipertensión intracraneana / Update on the management of intracranial hypertension syndrome

Elevated intracranial pressure (ICP) is a devastating complication, with great impact on neurological status and high morbidity and mortality. Intracranial hypertension (ICH) has multiple etiologies. The natural history of this condition can lead to brain death. The successful management of patients with elevated ICP (> 20-25 mmHg) requires fast and timely recognition, judicious use of invasive monitoring and therapies aimed to reversing its underlying cause. Therefore, it must be managed as a neurological emergency. The objective of this review is to present in a friendly way the diagnostic approach and the management of ICH, focused on general practitioners.

Progress of hyperventilation syndrome in children / 国际儿科学杂志

Hyperventilation syndrome(HVS)in children is a common functional respiratory disorder with a group of symptoms mainly characterized by hyperventilation, which is usually triggered by anxiety or stress events.A standardized questionnaire and the hyperventilation provocation test are helpful for diagnosis.Currently, the Nijmegen questionnaire is a common clinical tool to quantify and assess the severity of the symptoms.Emotional and psychological factors are major causes of HVS onset, meanwhile, abnormal breathing patterns are also implicated.Reassurance therapy and breathing retraining can improve the symptoms.

Effects of nasal breathing on partial pressure of carbon dioxide in arterial blood during prolonged exercise in a hot environment / 体力科学

Prolonged exercise in a hot environment increases the minute ventilation (VE) and respiratory rate (RR) with an increase in core temperature. This hyperthermia-induced hyperventilation decreases the partial pressure of arterial blood carbon dioxide (PaCO2). Conversely, nasal breathing during exercise has been reported to produce low VE and RR values and high PaCO2 values; however, no studies have investigated this in hot environments. Therefore, the purpose of this study was to clarify the effect of nasal breathing on estimated partial pressure of carbon dioxide in arterial blood (PaCO2,estimate) during prolonged exercise in a hot environment. Twelve university endurance athletes participated in the study and performed a 40-minutes steady-state cycling exercise at an intensity of 55% of peak oxygen uptake in a hot environment (room temperature 35℃, relative humidity 40%). Using randomized crossover design, two experiments were performed—nasal breathing condition (NB) and mouth breathing condition (MB). Moreover, physiological indices were measured during the exercise. Rectal temperature increased in both conditions, but there was no significant difference between these conditions. PaCO2,estimate values were significantly higher in NB between 10 minutes and 40 minutes of exercise (p < 0.05) compared to MB, and decreased with time in MB. Compared to MB, the VE was significantly lower in NB between 30 minutes and 40 minutes (p < 0.05), while the RR was significantly lower in NB between 25 minutes and 40 minutes of exercise (p < 0.05). Therefore, nasal breathing during a prolonged moderate-intensity exercise in a hot environment prevented the decrease in PaCO2,estimate due to hyperthermia-induced hyperventilation.

Design and application of a push-pull adjustable artificial dead space / 中华危重病急救医学

Using artificial dead space to correct hypocapnia or induce hypercapnia is of particular significance for diagnosing and treating specific neurocritical diseases. At present, the above purpose is mainly achieved by adding an extension tube between the Y-type connector of the ventilator and the artificial airway in clinical practice. However, its volume is often fixed and cannot adapt to the individualized diagnosis and treatment in different clinical scenarios. The research group led by Professor Zhou Jianxin from the department of critical care medicine of Beijing Tiantan Hospital, Capital Medical University, has designed an artificial dead cavity with adjustable volume based on years of research in the respiratory field and has been granted a national utility model patent (patent number: ZL 2020 2 0496413.4). The artificial dead chamber is simple in structure, composed of a barrel body, a piston head, and a push-pull rod. By freely adjusting the size of the artificial dead chamber volume, it can accurately regulate the target carbon dioxide, correct the spontaneous hyperventilation, terminate intractable hiccup, and shorten the operation time of asphyxia test in clinical diagnosis of brain death while correcting hypocapnia or inducing hypercapnia. It has the advantages of solid reliability, convenient operation, and low production cost, which significantly facilitates scientific research and clinical diagnosis and treatment.

Hyperventilation Syndrome

Introduction: Hyperventilation syndrome refers to acollection of physical and emotional symptoms, broughtabout by hyperventilation. Though it is a relatively commonpresentation to the emergency department, there are only a fewstudies on hyperventilation syndrome (HVS) especially fromIndia. This study aims at studying the factors associated withhyperventilation syndrome in the current study population.Material and methods: A cross sectional study wasconducted on 83 patients with HVS. Patient responses wererecorded on Nijmegen questionnaire and Perceived stressscale and analyzed with descriptive statistics.Results: Study population included 83 patients, 78.32% ofthe populations were females and 21.68% were males. Themean age of the population is 19.28 years. 66.26% wereadolescents, 81.92% are students and 68.67% were residingin hostel. 12.05% had previous episodes of hyperventilation.Carpo-pedal spasm was the presenting symptom in 40.96%population and exams were the cause of stress for 32.5%population. The mean score on perceived stress scale is 24.92.59.03% had moderate and 38.55% had severe stress as perscores on perceived stress scale.Conclusion: High student population presenting with HVSand exams being the precipitating stressor, high scores onperceived stress scale emphasizes the need to address the needfor stress free curriculum and greater insights in to the issue.

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.

Effects of repeated sprint training on isocapnic buffering phase in volleyball players / Efeitos de treinos de sprint repetidos na faİxa de tamponamento İsocápnİco em jogadores de voleibol / Efectos del entrenamiento de sprint repetido en la fase de tamponamiento isocápnico en jugadores de voleibol

ABSTRACT Introduction: The region between the ventilatory threshold (VT) and respiratory compensation point (RCP) is defined as the isocapnic buffering (ICB) phase and represents a phase of compensation for exercise-induced metabolic acidosis. There is sparse literature examining the effects of physical training on ICB phase in athletes. Objectives: The purpose of this study was to examine the effects of a repeated sprint training program on the ICB phase of college volleyball players. Methods: Eighteen male volleyball players were randomly assigned to either an experimental group (n=9) or a control group (n=9) and followed a traditional volleyball training program three times per week for six weeks. The experimental group additionally performed a repeated sprint training protocol immediately before each volleyball training session. Before and after the 6-week training period, all participants performed an incremental treadmill test to determine VT, RCP, and maximal oxygen uptake (VO2max). The ICB phases were calculated as VO2 (ml/kg/min) and sprint speed (km/h). Results: The experimental group showed significant improvements in ICB phase, RCP, VO2max and maximal sprint speed after training (p<0.01). There were no significant changes in VT after training in the experimental group (p>0.05). None of these variables changed significantly in the control group (p>0.05). Conclusions: These findings indicate that repeated sprint training can enhance the ICB phase of volleyball players, which may be attributable to an improvement in buffering capacity leading to a shift in RCP towards higher intensities without any change in VT. The increase in the ICB phase may an important factor in terms of improvement in the high-intensity exercise tolerance of athletes. Level of Evidence II; Therapeutic studies - Investigating the results of treatment.

RESUMO Introdução: a região entre o limiar ventilatório (VT) e o ponto de compensação respiratório (RCP) é definido como faixa de temporamento isocápnico (ICB) e representa a fase de compensação para a acidose metabólica induzida por exercício. Há escassa literatura examinando os efeitos do treinamento físico na fase ICB em atletas. Objetivos: o objetivo desse estudo foi examinar os efeitos do programa de treinamento de Srint repetido na fase ICB em jogadores universitários de voleibol. Métodos: dezoito jogadores homens de voleibol foram aleatoriamente designados para um grupo experimental (n=9) ou um grupo controle (n=9) e completaram um programa tradicional de treinamento de voleibol três vezes por semana, durante seis semanas. O grupo experimental, adicionalmente, realizou um protocolo de treinamento de sprint repetido imediatamente antes de cada sessão de treinamento de voleibol. Antes e após o período de treinamento de 6 semanas, todos os participantes realizaram um teste de esteira experimental para determinar VT, RCP e consumo máximo de oxigênio (VO2max). As fases ICB foram calculadas como VO2 (ml/kg/min) e velocidade de corrida (km/h). Resultados: o grupo experimental mostrou melhorias significativas na fase ICB, RCP, VO2max e velocidade de corrida máxima depois do treino (p < 0.01). Não houve mudanças significativas no VT após o treino no grupo experimental (p > 0.05). Nenhuma das variáveis mudou significativamente no grupo controle (p > 0.05). Conclusões: a partir desses resultados, concluímos que o treinamento de Sprint repetido pode realçar a fase ICB em jogadores de voleibol, que podem ser atribuídos à melhora do efeito tampão, levando ao deslocamento da RCP para intensidades mais altas, sem nenhuma mudança no VT. O aumento na fase ICB pode ser um fator importante em relação à melhora na tolerância ao exercício de alta intensidade em atletas. Nível de evidência II, Estudos terapêuticos - Investigação dos resultados do tratamento.

RESUMEN Introducción: la región comprendida entre el umbral de ventilación (UV) y el punto de compensación respiratoria (PCR) se define como la fase de amortiguación isocapnica (ICB) y representa una fase de compensación de la acidosis metabólica inducida por el ejercicio. Hay poca literatura que examine los efectos del entrenamiento físico en la fase ICB de los atletas. Objetivos: El propósito de este estudio fue examinar los efectos del programa de entrenamiento de sprints repetidos en la fase ICB de los jugadores de voleibol de la universidad. Métodos: Dieciocho jugadores de voleibol masculino fueron asignados aleatoriamente a un grupo experimental (n=9) o un grupo de control (n=9) y completaron un programa tradicional de entrenamiento de voleibol, tres veces por semana durante 6 semanas. El grupo experimental también realizó un protocolo de entrenamiento de sprint repetido inmediatamente antes de cada sesión de entrenamiento de voleibol. Antes y después del período de entrenamiento de 6 semanas, todos los participantes realizaron una prueba incremental en cinta rodante para determinar UV, RCP y consumo máximo de oxígeno (VO2max). Las fases ICB se calcularon como VO2 (ml/kg/min) y velocidad (km/h). Resultados: El grupo experimental mostró mejoras significativas en la fase ICB, RCP, VO2max y velocidad de carrera máxima post entrenamiento (p < 0.01). No hubo cambios significativos en UV después del entrenamiento en el grupo experimental (p > 0.05). Ninguna de estas variables cambió significativamente en el grupo control (p > 0.05). Conclusiones: A partir de estos resultados, concluimos que el entrenamiento de sprints repetidos puede mejorar la fase ICB de los jugadores de voleibol, lo que puede atribuirse a la mejora de la capacidad de amortiguación que lleva al cambio de RCP a intensidades más altas sin ningún cambio en el UV. El aumento en la fase ICB puede ser un factor importante en relación con la mejora en la tolerancia al ejercicio de alta intensidad en atletas. Nivel de Evidencia II; Estudios terapéuticos - Investigando resultados del tratamiento.

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.

<b>Five Cases of Acute Ventilation Attack Successfully Treated with Shigyakusan in the Emergency Department</b> / 日本東洋医学雑誌

We report five cases of acute hyperventilation attack, with bilateral fullness of the chest and hypochondrium, and bilateral rectus abdominis muscle strain, that were successfully treated with shigyakusan. Case 1 was a 47-year-old female ; case 2 was an 18-year-old female ; case 3 was a 23-year-old female ; case 4 was a 39-year-old male ; and case 5 was a 40-year-old male. All five patients visited the emergency department with complaints of severe dyspnea and tetany. Their abdominal signs were characteristic, with remarkable bilateral fullness of the chest and hypochondrium and bilateral rectus abdominis muscle strain. In cases 1 to 4, the patients were given 2.5 g of shigyakusan extract, and their symptoms promptly improved. In case 5, as the patient could not swallow the prescribed medication at presentation, intramuscular diazepam was given. Thereafter, he complained of continuous severe numbness ; we subsequently gave him shigyakusan, and his numbness promptly improved. In conclusion, shigyakusan seems to be a useful Kampo drug for the treatment of acute hyperventilation attack.

To analyze the risk factors of tetany in patients with hyperventilation syndrome / 天津医药

Objective To explore the risk factors causing tetany in patients with hyperventilation syndrome. Meth?ods A total of 103 patients with hyperventilation syndrome treated in our hospital were included in this study. According to whether there was tetany, patients were divided into tetany group and non-tetany group. Values of gender, age, electrolyte, pH and p(CO2) were analysed between two groups. The factors of P0.05). It was revealed that the younger age, the lower level of the serum K+, serum phosphorus and p(CO2) were the risk factors of tetany through binary Logistic regression analysis. Conclusion The risk factors of tetany in patients with hyperventilation syndrome include younger age, lower level of serum K+and serum phosphorus and reduced p(CO2).

Ventilação mecânica em neurocirurgia / Mechanical ventilation in neurosurgery

A ventilação artificial em pacientes neurocirúrgicos apresenta aspectos técnicos específicos como a hiperventilação e aplicação de pressão expiratória final positiva (PEEP). As medidas geralmente utilizadas para proteção pulmonar, tais como altos níveis de PEEP, baixos volumes correntes, elevadas frequências respiratórias e hipercapnia permissiva podem ser danosas em pacientes com doença neurológica. A influência da ventilação mecânica sobre os parâmetros hemodinâmicos, notadamente sobre a pressão intracraniana (PIC) e a pressão de perfusão cerebral (PPC), tem sido foco de diversos estudos, embora os resultados permaneçam controversos. No centro da discussão, destaca-se o papel da PEEP e suas implicações nessa população. A partir dos dados disponíveis na literatura, ainda que controversos, existe a tendência a se inferir que o uso da PEEP em níveis baixos a moderados pouco provavelmente causará aumento significativo da PIC na grande maioria dos casos. Enquanto a vasoconstrição cerebral induzida pela hipocapnia por hiperventilação reduz efetivamentea a PIC, o risco de diminuir o fluxo sanguíneo cerebral (FSC) abaixo do seu limite crítico sempre foi foco de preocupação clínica e investigação científica. Faltam dados na literatura acerca do uso de manobras de recrutamento alveolar em pacientes neurocirúrgicos. Estratégias de proteção pulmonar devem ser sempre respeitadas, mas simultaneamente devem-se otimizar a PPC e PIC. A monitorização da ventilação é de suma importância, visto que há forte influência dos parâmetros respiratórios na fisiologia cerebral.

The mechanical ventilation in neurological patients indicates some aspects related to the techniques used, such as hyperventilation and the application of positive end-expiratory pressure (PEEP). The measures generally adopted for lung protective ventilation, such as high levels of PEEP, low tidal volume, elevated respiratory frequency, and permissive hypercapnia can be damaging for patients with neurological disesases. The influence of mechanical ventilation on hemodynamic parameters, such as intracranial pressure (ICP) and cerebral perfusion pressure (CPP) has been the focus of many studies, even though the results are still controversial. The role of PEEP and its implications in neurological patients is in evidence. Based on data available in the literature, albeit controversial, there is a tendency toinfer that the use of PEEP at low to moderate levels is unlikely to cause a significantincrease in ICP. While cerebral vasoconstriction induced by hypocapnia reduces effectively ICP, the risk of reducing cerebral blood flow (CBF) to a critical condition level was always a clinical concern and a subject of scientific investigation. There are few data about lung recruitment maneuver in this patient population.Lung protection strategiesshould alwaysbe respected, butsimultaneouslyoptimizeCPPandICP. Monitoring ofventilationisof paramountimportance, since there is a stronginfluenceof respiratory parametersin brainphysiology.

Hyperventilation Induced Syncope: Differential Feature of Head-up Tilt Table Test with Transcranial Doppler in Patient with Hyperventilation Syndrome from True Syncope

The causes of a transient loss of consciousness (TLOC) are divided into syncope, epileptic seizures, cerebrovascular diseases and functional disorders such as hyperventilation (HV) syndrome, psychogenic pseudosyncope. The differential diagnosis of TLOC is may be difficult due to lack of history, misleading features, or confusion over the definition of syncope. We have experienced a rare case of HV syncope that TLOC developed after HV from mental stress, and differentiated by head-up tilt table test with transcranial doppler.

Dynamic optic nerve sheath diameter responses to short-term hyperventilation measured with sonography in patients under general anesthesia / 대한마취과학회지

BACKGROUND: Rapid evaluation and management of intracranial pressure (ICP) can help to early detection of increased ICP and improve postoperative outcomes in neurocritically-ill patients. Sonographic measurement of optic nerve sheath diameter (ONSD) is a non-invasive method of evaluating increased intracranial pressure at the bedside. In the present study, we hypothesized that sonographic ONSD, as a surrogate of ICP change, can be dynamically changed in response to carbon dioxide change using short-term hyperventilation. METHODS: Fourteen patients were enrolled. During general anesthesia, end-tidal carbon dioxide concentration (ETCO2) was decreased from 40 mmHg to 30 mmHg within 10 minutes. ONSD, which was monitored continuously in the single sonographic plane, was repeatedly measured at 1 and 5 minutes with ETCO2 40 mmHg (time-point 1 and 2) and measured again at 1 and 5 minutes with ETCO2 30 mmHg (time-point 3 and 4). RESULTS: The mean +/- standard deviation of ONSD sequentially measured at four time-points were 5.0 +/- 0.5, 5.0 +/- 0.4, 3.8 +/- 0.6, and 4.0 +/- 0.4 mm, respectively. ONSD was significantly decreased at time-point 3 and 4, compared with 1 and 2 (P < 0.001). CONCLUSIONS: The ONSD was rapidly changed in response to ETCO2. This finding may support that ONSD may be beneficial to close ICP monitoring in response to CO2 change.

Dynamic optic nerve sheath diameter responses to short-term hyperventilation measured with sonography in patients under general anesthesia / 대한마취과학회지

BACKGROUND: Rapid evaluation and management of intracranial pressure (ICP) can help to early detection of increased ICP and improve postoperative outcomes in neurocritically-ill patients. Sonographic measurement of optic nerve sheath diameter (ONSD) is a non-invasive method of evaluating increased intracranial pressure at the bedside. In the present study, we hypothesized that sonographic ONSD, as a surrogate of ICP change, can be dynamically changed in response to carbon dioxide change using short-term hyperventilation. METHODS: Fourteen patients were enrolled. During general anesthesia, end-tidal carbon dioxide concentration (ETCO2) was decreased from 40 mmHg to 30 mmHg within 10 minutes. ONSD, which was monitored continuously in the single sonographic plane, was repeatedly measured at 1 and 5 minutes with ETCO2 40 mmHg (time-point 1 and 2) and measured again at 1 and 5 minutes with ETCO2 30 mmHg (time-point 3 and 4). RESULTS: The mean +/- standard deviation of ONSD sequentially measured at four time-points were 5.0 +/- 0.5, 5.0 +/- 0.4, 3.8 +/- 0.6, and 4.0 +/- 0.4 mm, respectively. ONSD was significantly decreased at time-point 3 and 4, compared with 1 and 2 (P < 0.001). CONCLUSIONS: The ONSD was rapidly changed in response to ETCO2. This finding may support that ONSD may be beneficial to close ICP monitoring in response to CO2 change.

Application of early tracheotomy combined with hyperventilation in the treatment of hypertensive cerebral hemorrhage / 中国基层医药

Objective To explore the effect of early tracheotomy combined with hyperventilation in the treatment of hypertensive cerebral hemorrhage.Methods Clinical data of 76 patients with hypertensive cerebral hemorrhage after operation were retrospectively analyzed,and they were divided into treatment group and control group depending on whether received early tracheal incision joint hyperventilation.3 months after the treatment,the prognosis of the two groups was evaluated and compared according to the Glasgow Coma Score (GCS).Results In the treatment group,there were good in 10 cases,mild disability in 10 cases,severe disability in 9 cases,vegetative state in 3 cases,deaths in 4 cases.In the control group,there were good in 7 cases,mild disability in 7 cases,severe disability in 11 cases,vegetative state patients in 5 cases,deaths in 10 cases,and the efficacy of the treatment group was significantly better than that of the control group (x2 =6.290,P =0.043).In the treatment group,there were 5 cases of electrolyte imbalance,6 cases of kidney dysfunction,8 cases of stress ulcer,8 cases of lung infection.In the control group,there were 11 cases of electrolyte disturbances,10 cases of renal dysfunction,11 cases of stress ulcer,15 cases of lung infection.The incidence rate of complications of the treatment group was significantly lower than the control group (x2 =831.6,P =0.020).Conclusion For hypertensive cerebral hemorrhage,early tracheotomy combined with hyperventilation treatment can improve the patients' survival rate and life quality.

Hipocapnia en neuroanestesia: estado actual / Hypocapnia in Neuroanesthesia: Current Situation

Introducción: La hiperventilación ha sido una maniobra común en el manejo anestésico de procedimientos neuroquirúrgicos. Hace unos años había escepticismo entre los médicos sobre si esto resultaba en isquemia cerebral. Hoy sabemos que es perjudicial y deteriora el estado y el pronóstico del paciente. Objetivo: Hacer una revisión de los efectos adversos de la hipocapnia en diferentes órganos, principalmente el cerebro, e identificar las recomendaciones actuales de su utilidad. Métodos: Realizamos una búsqueda de la literatura en la base de datos de PubMed utilizando términos MeSH incluidos en las palabras clave; se amplió con la revisión de algunos textos y la bibliografía de los artículos más relevantes. Resultados: Con la revisión de la literatura, se ha demostrado que la hipocapnia es perjudicial tanto para el cerebro como para otros tejidos, y la recomendación actual es utilizarla sólo en dos situaciones (en caso de herniación inminente y para mejorar el campo quirúrgico) y por 20 min. Conclusiones: La hiperventilación no debe ser una intervención anestésica rutinaria en el manejo del paciente neuroquirúrgico; debe tener una indicación precisa y, una vez la indicación haya cesado, la intervención debe ser retirada lo más pronto posible.

Introduction: Hyperventilation has been a usual maneuver in the management of anesthesia in neurosurgical procedures. A few years back there used to be some medical skepticism about the potential of cerebral ischemia and today we know that it is detrimental and worsens the patient’s condition and prognosis. Objective: To review the adverse effects of hypocapnia on various organs -mainly the brain- and to identify the current recommendations about its use. Methodology: We conducted a PubMed literature search using MeSH terminology including the key words. The search was expanded to include a review of several texts and the bibliography of the most relevant articles. Results: The literature review showed that hypocapnia is harmful for the brain and for other tissues and the current recommendation is to use it for two situations only: in case of imminent herniation and to improve the surgical field, limited to 20 minutes. Conclusions: Hyperventilation should not be a routine anesthetic intervention for the management of the neurosurgical patient; there must be a precise indication and once the situation is corrected, the intervention must be immediately withdrawn.

Descripción, interpretación, análisis e importancia del nistagmus inducido por la hiperventilación en el estudio de patologías vestibulares periféricas y centrales / Description, interpretation, analysis and importance of hyperventilation -induced nystagmus in the study of the peripheral and central vestibular disorders

Recientes estudios clínicos han revelado la utilidad del test del nistagmus inducido por la hiperventilación aguda, en la investigación de patologías vestibulares retrolaberínticas, neurales y de origen central, con la aparición de nistagmus paréticos o bien excitatorios. El propósito de este estudio ha sido: primero, conocer la sensibilidad de este examen según el análisis de los estudios de diferentes autores; segundo, entender la fisiopatología de este nistagmus inducido por la hiperventilación y tercero, efectuar una interpretación y análisis de este examen que permita obtener conclusiones sólidas del mejor nivel de medicina basada en evidencias. Para efectuar este estudio y análisis se procedió a una investigación exhaustiva de las publicaciones sobre el tema en los últimos 25 años, recurriendo para ello como fuentes de información a las principales bases de datos biomédicos y a la revisión en texto completo de estas publicaciones. Llamó la atención la escasez de trabajos clínicos publicados sobre el tema que no superan los 40, y también la escasez de trabajos sobre la fisiopatología del nistagmus inducido por la hiperventilación aguda. La metódica del test es muy simple por lo que su utilización resulta muy atractiva, con un escaso número de falsos positivos. La mayor parte de los estudios publicados, se focaliza en su utilización en el schwanoma vestibularyen la neuronitis vestibular. Respecto al schwanoma vestibular de un total de 107 pacientes estudiados el test fue positivo en el 80 por ciento de los casos, con aparición de nistagmus ipsilesional o contralesional. En la neuronitis vestibular la positividad del test alcanzó a 60 por ciento de un total de 272 pacientes estudiados y que estaba en relación directa con el tiempo de evolución de la enfermedad. En la esclerosis múltiple, en pacientes con síntomas vestibulares, la positividad del test fue de 75 por ciento, en cambio en aquellos pacientes sin síntomas vestibulares...

Recent clinical studies have revealed the usefulness of the hyperventilation-induced nystagmus in retrolabyrinthine and central vestibular diseases with the appearance either excitatory (ipsilateral) or paretic (contralateral) nystagmus. The objectives of this study have been: 1) to get to know the sensitivity of the exam, according to the best literature available; 2) to get to know the physiopathology of this hyperventilation-induced nystagmus, and 3) to carry out an analysis and interpretation of this exam in order to reach solid conclusions of the highest level in evidence based medicine. An exhaustive research of literature published on this topic in the last 25 years was carried out. The main source of information being the most important medical data-based publications and also a thorough revision of these texts. The scarce number of publications on this topic (not more than 40) is what strikes the attention most, as well as the very few studies of the physiopathology of the hyperventilation-induced nystagmus. The method of the test is a simple one; this fact makes its application an attractive one, with a low number of false positive. Most of the studies published are focused on its application in the vestibular schwannoma and in the vestibular neuritis. As to what the Vestibular schwannoma is concerned, ofa group of 107 patients studied, the test was positive in 80 percent of the cases, with the appearance of ipsilesional or contralesional nystagmus. In vestibular neuritis the test was positive in 68 percent of a number of 272 patients; this amount was in direct correlation with the time of evolution of the disease. In multiple sclerosis, in patients with vestibular symptoms, the test gave positive in 75 percent, whereas in those patients without vestibular symptoms it was positive only in 7 percent. In patients with cerebellar diseases, particularly degenerative ones this test was positive in 78 percent of the cases...