Pulmonary strain and end-expiratory lung volume during apnea test: a comparative analysis using electrical impedance tomography.

The apnea test, employed for brain death assessment, aims to demonstrate the absence of respiratory drive due to hypercapnia. The tracheal oxygen insufflation apnea test mode (I-AT) involves disconnecting the patient from invasive mechanical ventilation (iMV) for approximately 8 minutes while maintaining oxygenation. This test supports the diagnosis of brain death based on a specified increase in PaCO2. Common complications include hypoxemia and hemodynamic instability, and lung collapse-induced reduction in end-expiratory lung volume (EELV). In our case series utilizing electrical impedance tomography (EIT), we observed that continuous positive airway pressure during the apnea test (CPAP-AT) effectively mitigated lung collapse. This resulted in improved pulmonary strain compared to the disconnection of iMV. These findings suggest the potential benefits of routine CPAP-AT, particularly for potential lung donors, emphasizing the relevance of our study in providing quantitative insights into EELV loss and its association with pulmonary strain and potential lung injury.

La prueba de apnea es una técnica diagnóstica ampliamente utilizada para la evaluación de la muerte cerebral, con el objetivo de demostrar la ausencia de impulso respiratorio debido a la hipercapnia. La variante de la prueba de apnea con insuflación de oxígeno traqueal (I-AT) implica desconectar al paciente de la ventilación mecánica invasiva (iVM) durante aproximadamente 8 minutos, manteniendo la oxigenación mediante un catéter de insuflación. Esta prueba respalda el diagnóstico de muerte cerebral cuando se determina un aumento de la PaCO 2 superior a 20 mmHg en comparación con el valor inicial o un nivel de PaCO 2 superior a 60 mmHg al final de la prueba. En nuestra serie de casos, la implementación de la tomografía de impedancia eléctrica (EIT) reveló que la prueba de apnea con presión positiva continua (CPAPAT) mitiga eficazmente el colapso pulmonar. Este enfoque resulta en una mejora en la tensión pulmonar en comparación con la desconexión de iMV, demostrando su relevancia en el contexto de potenciales donantes de pulmones.

P2X3 receptor antagonism reduces the occurrence of apnoeas in newborn rats.

Hyperreflexia of the peripheral chemoreceptors is a potential contributor of apnoeas of prematurity (AoP). Recently, it was shown that elevated P2X3 receptor expression was associated with elevated carotid body afferent sensitivity. Therefore, we tested whether P2X3 receptor antagonism would reduce AoP known to occur in newborn rats. Unrestrained whole-body plethysmography was used to record breathing and from this the frequency of apnoeas at baseline and following administration of either a P2X3 receptor antagonist - AF-454 (5 mg/kg or 10 mg/kg s.c.) or vehicle was derived. In a separate group, we tested the effects of AF-454 (10 mg/kg) on the hypoxic ventilatory response (10 % FiO2). Ten but not 5 mg/kg AF-454 reduced the frequency of AoP and improved breathing regularity significantly compared to vehicle. Neither AF-454 (both 5 and 10 mg/kg) nor vehicle affected baseline respiration. However, P2X3 receptor antagonism (10 mg/kg) powerfully blunted hypoxic ventilatory response to 10 % FiO2. These data suggest that P2X3 receptors contribute to AoP and the hypoxic ventilatory response in newborn rats but play no role in the drive to breathe at rest.

Monitorización cardio respiratoria domiciliaria en lactantes / Home respiratory cardio monitoring in infants

Home cardio-respiratory monitoring began over 40 years ago with the aim of preventing sudden infant death. Although it has been shown that monitoring does not meet this objective, its prescription has been maintained in various clinical situations and with very different criteria. Consensus on the subject has not been able to define precisely the type of monitoring or the time required for different diseases. Among the diseases that still consider the indication of cardio-respiratory monitoring at home are: persistent apnea of prematurity, high-risk BRUE (Brief Resolved Unexplained Events), neurological or metabolic diseases with compromise of the respiratory center, convulsive cough, pathologic gastroesophageal reflux and technology-dependent patients (high flow nasal cannula (CNAF), noninvasive ventilation (NIV), invasive mechanical ventilation (IMV) to tracheostomy, and others). A review is presented on the development of cardio-respiratory monitoring at home, highlighting the true usefulness of this technology with a general proposal, which must be evaluated on a case-by-case basis and always taking into account the conditions that must be met to perform adequate monitoring and useful.

La monitorización cardio-respiratoria en domicilio se inició hace más de 40 años con el objetivo de prevenir la muerte súbita del lactante. Aun cuando se ha demostrado que la monitorización no cumple este objetivo, se ha mantenido su prescripción en diversas situaciones clínicas y con criterios muy diversos. Consensos acerca del tema no han llegado a definir con precisión el tipo de monitorización ni el tiempo requerido para distintas enfermedades. Dentro de las enfermedades que todavía consideran la indicación de monitorización cardio-respiratoria en domicilio se encuentran: apnea persistente del prematuro, BRUE (episodio breve resuelto inexplicado) de alto riesgo, enfermedades neurológicas o metabólicas con compromiso del centro respiratorio, tos convulsiva, reflujo gastroesofágico patológico y pacientes dependientes de tecnología (cánula nasal de alto flujo (CNAF), ventilación no invasiva (VNI), ventilación mecánica invasiva (VMI) a traqueostomía, y otros). Se presenta una revisión sobre el desarrollo de la monitorización cardio-respiratoria en domicilio, resaltando la verdadera utilidad que tendría esta tecnología con una propuesta general, que debe evaluarse caso a caso y siempre teniendo en cuenta las condiciones que deben cumplirse para realizar una monitorización adecuada y útil.

Carotid Body-Mediated Chemoreflex Drive in The Setting of low and High Output Heart Failure.

Enhanced carotid body (CB) chemoreflex function is strongly related to cardiorespiratory disorders and disease progression in heart failure (HF). The mechanisms underlying CB sensitization during HF are not fully understood, however previous work indicates blood flow per se can affect CB function. Then, we hypothesized that the CB-mediated chemoreflex drive will be enhanced only in low output HF but not in high output HF. Myocardial infarcted rats and aorto-caval fistulated rats were used as a low output HF model (MI-CHF) and as a high output HF model (AV-CHF), respectively. Blood flow supply to the CB region was decreased only in MI-CHF rats compared to Sham and AV-CHF rats. MI-CHF rats exhibited a significantly enhanced hypoxic ventilatory response compared to AV-CHF rats. However, apnea/hypopnea incidence was similarly increased in both MI-CHF and AV-CHF rats compared to control. Kruppel-like factor 2 expression, a flow sensitive transcription factor, was reduced in the CBs of MI-CHF rats but not in AV-CHF rats. Our results indicate that in the setting of HF, potentiation of the CB chemoreflex is strongly associated with a reduction in cardiac output and may not be related to other pathophysiological consequences of HF.

Biphasic cardiovascular and respiratory effects induced by ß-citronellol.

ß-Citronellol is a monoterpene found in the essential oil of various plants with antihypertensive properties. In fact, ß-citronellol possesses hypotensive actions due to its vasodilator abilities. Here we aimed to show that ß-citronellol recruits airway sensory neural circuitry to evoke cardiorespiratory effects. In anesthetized rats, intravenous injection of ß-citronellol caused biphasic hypotension, bradycardia and apnea. Bilateral vagotomy, perivagal capsaicin treatment or injection into the left ventricle abolished first rapid phase (named P1) but not delayed phase P2 of the ß-citronellol effects. P1 persisted after pretreatment with capsazepine, ondansetron, HC-030031 or suramin. Suramin abolished P2 of apnea. In awake rats, ß-citronellol induced biphasic hypotension and bradycardia being P1 abolished by methylatropine. In vitro, ß-citronellol inhibited spontaneous or electrically-evoked contractions of rat isolated right or left atrium, respectively, and fully relaxed sustained contractions of phenylephrine in mesenteric artery rings. In conclusion, chemosensitive pulmonary vagal afferent fibers appear to mediate the cardiovascular and respiratory effects of ß-citronellol. The transduction mechanism in P1 seems not to involve the activation of transient receptor potential vanilloid subtype 1 (TRPV1), transient receptor potential ankyrin subtype 1 (TRPA1), purinergic (P2X) or 5-HT3 receptors located on airways sensory nerves. P2 of hypotension and bradycardia seems resulting from a cardioinhibitory and vasodilatory effect of ß-citronellol and the apnea from a purinergic signaling.

Brainstem areas activated by intermittent apnea in awake unrestrained rats.

We investigated the role of the autonomic nervous system to cardiovascular responses to obstructive apnea in awake, unrestrained rats, and measured expression of Fos induced by apnea in the brainstem. We implanted a tracheal balloon contained in a rigid tube to allow the induction of apnea without inducing pain in the trachea. During bouts of 15s of apnea, heart rate fell from 371±8 to 161±11bpm (mean±SEM, n=15, p<0.01) and arterial pressure increased from 115±2 to 131±4mmHg (p<0.01). Bradycardia was due to parasympathetic activity because it was blocked by the muscarinic antagonist, methylatropine. The pressor response was due to vasoconstriction caused by sympathetic activation because it was blocked by the α1 antagonist, prazosin. Apnea induced Fos expression in several brainstem areas involved in cardiorespiratory control such as the nucleus of the solitary tract (NTS), ventrolateral medulla (VLM), and pons. Ligation of the carotid body artery reduced apnea-induced bradycardia, blocked heart rate responses to i.v. injection of cyanide, reduced Fos expression in the caudal NTS, and increased Fos expression in the rostral VLM. In conclusion, apnea activates neurons in regions that process signals from baroreceptors, chemoreceptors, pulmonary receptors, and regions responsible for autonomic and respiratory activity both in the presence and absence of carotid chemoreceptors.

Is Primary Hyperparathyroidism a Risk Factor for Papillary Thyroid Cancer? An Exemplar Study and Literature Review

Introduction Primary hyperparathyroidism (PHPT) is associated with several cancer types, including papillary thyroid carcinoma (PTC). Objective To explore further the relation between PHPT and PTC. Methods By considering patients with PHPT as extra-suspicious for PTC, we studied an exemplar group of patients with PHPT with a small (1 cm) thyroid nodule, which was negative in preoperative cytologic examination. During parathyroidectomy, a frozen section biopsy of the thyroid nodule confirmed PTC, as did the final surgical specimen, revealing that the preoperative cytology was false-negative. Additionally, relevant reports retrieved from the English literature addressing thyroid cancer and hyperparathyroidism were reviewed and processed. Results Four patients with PHPT were studied. Three had a multifocal thyroid disease, and three had neck lymph node metastasis. Processing previous report data supported an association between PHPT and PTC. Although thyroid nodularity among patients with PHPTwas similar to the general population, PTC incidence was higher. This was true also for patients with secondary hyperparathyroidism. Conclusions This study emphasized that PHPT should be considered as a noteworthy risk factor for PTC. Fine needle aspiration of a thyroid nodule is the most valuable diagnostic procedure for thyroid cancer. Yet, false-negative results were reported in up to 10% of cases, especially in small, subcentimeter nodules. In line with our data and the literature, patients with PHPT should have both a detailed ultrasound addressing the thyroid and cytology of any thyroid nodule, including small subcentimeter lesions. Moreover, surgical flexibility, allowing intraoperative thyroid nodule sampling, should be considered even for "innocent" nodules. .

Quality of Life in Swallowing Disorders after Nonsurgical Treatment for Head and Neck Cancer

Introduction Radiotherapy or chemoradiotherapy can result in severe swallowing disorders with potential risk for aspiration and can negatively impact the patient's quality of life (QOL). Objective To assess swallowing-related QOL in patients who underwent radiotherapy/ chemoradiotherapy for head and neck cancer. Methods We interviewed 110 patients (85 men and 25 women) who had undergone exclusive radiotherapy (25.5%) or concomitant chemoradiotherapy (74.5%) from 6 to 12 months before the study. The Quality of Life in Swallowing Disorders (SWAL-QOL) questionnaire was employed to evaluate dysphagia-related QOL. Results The QOL was reduced in all domains for all patients. The scores were worse among men. There was a relationship between oral cavity as the primary cancer site and the fatigue domain and also between advanced cancer stage and the impact of food selection, communication, and social function domains. Chemoradiotherapy association, the presence of nasogastric tube and tracheotomy, and the persistence of alcoholism and smoking had also a negative effect on the QOL. Conclusions According to the SWAL-QOL questionnaire, the dysphagia-related impact on QOL was observed 6 to 12 months after the treatment ended. .

Neonatal sensitization to ethanol-induced breathing disruptions as a function of late prenatal exposure to the drug in the rat: modulatory effects of ethanol's chemosensory cues.

Preclinical and clinical studies have systematically demonstrated abrupt changes in fetal respiratory patterns when the unborn organism is exposed to the effects of maternal ethanol intoxication. In subprimates, chronic exposure to this drug during gestation and infancy results in marked alterations of the plasticity of the respiratory network. These alterations are manifested in terms of an early incapability to overcome deleterious effects of hypoxic events as well as in terms of sensitization to ethanol's depressant effects upon breathing patterns. It has also been demonstrated that near term rat fetuses process ethanol's chemosensory cues when the drug contaminates the amniotic fluid and that associative learning processes occur due to the temporal contiguity existing between these cues and different ethanol-related physiological effects. In the present study during the course of late gestation (gestational days 17-20), pregnant rats were intragastrically administered with either 0.0 or 2.0 g/kg ethanol. Seven-day-old pups derived of these dams were evaluated in terms of respiration rates (breaths/min) and apneas when subjected to different experimental conditions. These conditions were defined by postnatal exposure to the drug (intragastric administrations of either 0.0, 0.5, 1.0 or 2.0 g/kg ethanol), postadministration time of evaluation (5-10 or 30-35 min) and olfactory context at test (no explicit ambient odor or ethanol ambient odor). The results, obtained via whole body plethysmography, indicated that brief prenatal experience with the drug sensitized the organisms to ethanol's depressant effects particularly when employing the higher ethanol doses. In turn, presence of ethanol odor at test potentiated the above mentioned respiratory alterations. Prenatal treatment with ethanol was not found to alter pharmacokinetic profiles resulting from postnatal exposure to the drug or to affect different morphometric parameters related with lung development. These results indicate that even brief exposure to the drug during late gestation is sufficient to sensitize the organism to later disruptive effects of the drug upon breathing responsiveness. These deficits are potentiated through the re-exposure to the olfactory context perceived in utero which is known to be associated with ethanol's unconditioned effects. As a function of these observations it is possible to suggest a critical role of fetal sensory and learning capabilities in terms of modulating later ethanol-related breathing disruptions.

Fisiopatología, diagnóstico diferencial y tratamiento de la apnea emotiva grave: A propósito de un caso clínico / Pathophysiology, differential diagnosis and treatment of severe emotional apnea: based on report case

Introduction: Emotional apneas (EA) are non-epileptic paroxysmal events affecting 5% of healthy children. The diagnosis is based on a stereotyped sequence of clinical events that start with tears caused by emotional stimulus, resulting in an autonomic nervous system alteration with transient color change, pale or cyanotic. 15% of the cases are associated with loss of consciousness, changes in tone or tonic-clonic movements secondary to hypoxia. Objective: To report a case of severe EA and to review the differential diagnosis and preventive treatments. Case report: A 15-month old infant with cyanotic emotional apnea since 8 months of age, triggered by pain, disgust or fear, increasing in frequency (3-4 per day) and intensity with altered consciousness and hypotonia. At 12 months, the patient also presented generalized tonic-clonic seizures of 3 minutes long, reason why the infant was admitted to the emergency service. Normal psychomotor development as well as normal physical, neurological and laboratory test results (without anemia) were found. Electroencephalography and brain MRI presented no abnormalities. Preventive therapy using Piracetam was performed in order to reduce crisis, which occurred in the first month of treatment. Conclusions: In most cases, a timely information delivery to parents is enough due to the benign nature and natural history of EA. However, when the frequency and severity of EA impact the child and family, to rule out heart disease or epilepsy and to seek preventive treatment options are required.

Introducción: Las apneas emotivas (AE) son eventos paroxísticos no epilépticos que afectan al 5% de niños sanos. El diagnóstico se basa en una secuencia estereotipada de eventos clínicos iniciado con llanto provocado por un estimulo emocional que desencadena una alteración refleja del sistema nervioso autonómico con cambio de color, pálido o cianótico. En el 15% se asocia a pérdida de conciencia, cambios del tono o movimientos tónico-clónicos secundarios a hipoxia. Objetivo: Presentar un caso clínico de AE grave, revisar el diagnóstico diferencial y tratamientos preventivos. Caso clínico: Lactante de 15 meses con cianóticas a partir de los 8 meses de edad, desencadenados por dolor, disgusto o miedo que aumentaron en frecuencia (3-4 por día) e intensidad con alteración de conciencia e hipotonía. A los 12 meses, se agregó además una crisis tónico clónica de 3 min de duración, por la cual ingresó a Servicio de Urgencia. Se constató un desarrollo psicomotor normal, examen físico, neurológico y parámetros de laboratorio normales (sin anemia), al igual que la electroencefalografía y resonancia magnética cerebral. Se inició terapia preventiva con piracetam con el propósito de disminuir las crisis, lo que se produjo desde el primer mes de tratamiento. Conclusiones: En la mayoría de los casos, la naturaleza benigna e historia natural de las AE permiten que una entrega de información oportuna a los padres sea suficiente. Sin embargo, cuando la frecuencia y severidad de las AE impactan al niño y su familia, se requiere descartar patología cardíaca o epilepsia y buscar opciones de tratamiento preventivo.

[Pathophysiology, differential diagnosis and treatment of severe emotional apnea: based on report case]. / Fisiopatología, diagnóstico diferencial y tratamiento de la apnea emotiva grave: A propósito de un caso clínico.

INTRODUCTION: Emotional apneas (EA) are non-epileptic paroxysmal events affecting 5% of healthy children. The diagnosis is based on a stereotyped sequence of clinical events that start with tears caused by emotional stimulus, resulting in an autonomic nervous system alteration with transient color change, pale or cyanotic. 15% of the cases are associated with loss of consciousness, changes in tone or tonic-clonic movements secondary to hypoxia. OBJECTIVE: To report a case of severe EA and to review the differential diagnosis and preventive treatments. CASE REPORT: A 15-month old infant with cyanotic emotional apnea since 8 months of age, triggered by pain, disgust or fear, increasing in frequency (3-4 per day) and intensity with altered consciousness and hypotonia. At 12 months, the patient also presented generalized tonic-clonic seizures of 3 minutes long, reason why the infant was admitted to the emergency service. Normal psychomotor development as well as normal physical, neurological and laboratory test results (without anemia) were found. Electroencephalography and brain MRI presented no abnormalities. Preventive therapy using Piracetam was performed in order to reduce crisis, which occurred in the first month of treatment. CONCLUSIONS: In most cases, a timely information delivery to parents is enough due to the benign nature and natural history of EA. However, when the frequency and severity of EA impact the child and family, to rule out heart disease or epilepsy and to seek preventive treatment options are required.

Reference values for respiratory events in overnight polygraphy from infants aged 1 and 3months.

OBJECTIVE: We aimed to determine reference values for respiratory indices in polygraphies (PGs) performed in infants aged 1 and 3months. METHODS: Healthy full-term neonates were recruited on the maternity ward. They were followed up by overnight PG at the age of 1month and again at the age of 3months. Indices of respiratory events, such as apneas, hypopneas, and percentage of periodic breathing were determined in each PG. Interpretation of PGs was performed blinded to the subject's data and the time of measurement. PG indices at 1 and 3months of age were compared. RESULTS: PG recordings were obtained for 37 healthy infants (22 boys). At the age of 1month, the median (minimum-maximum) central, obstructive, and mixed apnea index was 5.5 (0.9-44.3), 0.8 (0.1-6.7), and 0.3 (0-1.2), respectively. The same figures at the age of 3months were 4.1 (1.2-27.3), 0.8 (0-2.3), and 0.1 (0-0.8), respectively. Mixed obstructive apnea-hypopnea index (MOAHI) was 1.5 (0.2-7.0) and 0.9 (0.2-4.4) at the first and second measurements, respectively (P=.017). Only 1.2% of central apneas lasted longer than 20s. Periodic breathing was present in more than 90% of subjects studied. CONCLUSIONS: The infants in our study aged ⩽3months had respiratory event indices that were different from older children or adults. MOAHI showed a significant decrease during the first 3months after birth. We recommend that scoring of PG in infants of 3months or younger should consider age-specific reference values.

Anemia, apnea of prematurity, and blood transfusions.

OBJECTIVE: To compare the frequency and severity of apneic events in very low birth weight (VLBW) infants before and after blood transfusions using continuous electronic waveform analysis. STUDY DESIGN: We continuously collected waveform, heart rate, and oxygen saturation data from patients in all 45 neonatal intensive care unit beds at the University of Virginia for 120 weeks. Central apneas were detected using continuous computer processing of chest impedance, electrocardiographic, and oximetry signals. Apnea was defined as respiratory pauses of >10, >20, and >30 seconds when accompanied by bradycardia (<100 beats per minute) and hypoxemia (<80% oxyhemoglobin saturation as detected by pulse oximetry). Times of packed red blood cell transfusions were determined from bedside charts. Two cohorts were analyzed. In the transfusion cohort, waveforms were analyzed for 3 days before and after the transfusion for all VLBW infants who received a blood transfusion while also breathing spontaneously. Mean apnea rates for the previous 12 hours were quantified and differences for 12 hours before and after transfusion were compared. In the hematocrit cohort, 1453 hematocrit values from all VLBW infants admitted and breathing spontaneously during the time period were retrieved, and the association of hematocrit and apnea in the next 12 hours was tested using logistic regression. RESULTS: Sixty-seven infants had 110 blood transfusions during times when complete monitoring data were available. Transfusion was associated with fewer computer-detected apneic events (P < .01). Probability of future apnea occurring within 12 hours increased with decreasing hematocrit values (P < .001). CONCLUSIONS: Blood transfusions are associated with decreased apnea in VLBW infants, and apneas are less frequent at higher hematocrits.

Variation of the anal resting pressure induced by postexpiratory apnea effort in patients with constipation.

CONTEXT: Intestinal constipation--a common symptom among the general population--is more frequent in women. It may be secondary to an improper diet or organic or functional disturbances, such as dyskinesia of the pelvic floor. This is basically characterized by the absence of relaxation or paradoxical contraction of the pelvic floor and anal sphincter during evacuation. OBJECTIVE: To analyze, by manometric data, the anal pressure variation at rest, during evacuation effort by using the Valsalva maneuver and forced post-expiratory apnea in subjects with secondary constipation. METHODS: Twenty-one patients (19 females--90.4%) with a mean age of 47.5 years old (23-72) were studied. The diagnosis was performed using anorectal manometry, with a catheter containing eight channels disposed at the axial axis, measuring the proximal (1) and distal (2) portions of the anal orifice. The elevation of the pressure values in relation to the resting with the evacuation effort was present in all patients. The Agachan score was used for clinical evaluation of constipation. The variables studied were: mean anal pressure of the anal orifice for 20 seconds at rest, the effort of evacuation using Valsalva maneuver and the effort of evacuation during apnea after forced expiration, as well as the area under the curve of the manometric tracing at moments Valsalva and apnea. RESULTS: The analysis of the mean values of the anal pressure variation at rest evidenced difference between proximal and distal channels (P = 0.007), independent of the moment and tendency to differ during moments Valsalva and apnea (P = 0.06). The mean of values of the area under the manometric tracing curve showed differences between moments Valsalva and apnea (P = 0.0008), either at the proximal portion or at the distal portion of the anal orifice. CONCLUSION: The effort of evacuation associated with postexpiratory apnea, when compared with the effort associated with the Valsalva maneuver, provides lower elevation of anal pressure at rest by the parameter area under the curve.

Variation of the anal resting pressure induced by postexpiratory apnea effort in patients with constipation / Variação da pressão anal de repouso induzida pela apneia pós-esforço expiratório em pacientes com constipação intestinal

CONTEXT: Intestinal constipation - a common symptom among the general population - is more frequent in women. It may be secondary to an improper diet or organic or functional disturbances, such as dyskinesia of the pelvic floor. This is basically characterized by the absence of relaxation or paradoxical contraction of the pelvic floor and anal sphincter during evacuation. OBJECTIVE: To analyze, by manometric data, the anal pressure variation at rest, during evacuation effort by using the Valsalva maneuver and forced post-expiratory apnea in subjects with secondary constipation. METHODS: Twenty-one patients (19 females - 90.4 percent) with a mean age of 47.5 years old (23-72) were studied. The diagnosis was performed using anorectal manometry, with a catheter containing eight channels disposed at the axial axis, measuring the proximal (1) and distal (2) portions of the anal orifice. The elevation of the pressure values in relation to the resting with the evacuation effort was present in all patients. The Agachan score was used for clinical evaluation of constipation. The variables studied were: mean anal pressure of the anal orifice for 20 seconds at rest, the effort of evacuation using Valsalva maneuver and the effort of evacuation during apnea after forced expiration, as well as the area under the curve of the manometric tracing at moments Valsalva and apnea. RESULTS: The analysis of the mean values of the anal pressure variation at rest evidenced difference between proximal and distal channels (P = 0.007), independent of the moment and tendency to differ during moments Valsalva and apnea (P = 0.06). The mean of values of the area under the manometric tracing curve showed differences between moments Valsalva and apnea (P = 0.0008), either at the proximal portion or at the distal portion of the anal orifice. CONCLUSION: The effort of evacuation associated with postexpiratory apnea, when compared with the effort associated with the Valsalva maneuver, provides lower elevation of anal pressure at rest by the parameter area under the curve.

CONTEXTO: A constipação intestinal é um sintoma comum na população, sendo mais frequente em mulheres, podendo ser secundária a erro alimentar, distúrbios orgânicos ou funcionais. Dentre estes, destaca-se a discinesia do assoalho pélvico, caracterizada basicamente por ausência de relaxamento ou contração paradoxal da musculatura pélvica e do canal anal no momento da evacuação. O melhor conhecimento dos mecanismos envolvidos na constipação de etiologia funcional pode contribuir em terapêuticas mais eficazes. OBJETIVO: Analisar através de dados manométricos, a variação da pressão anal de repouso durante o esforço de evacuação com a manobra de Valsalva e apneia pós-expiração forçada em pacientes com constipação. MÉTODOS: Foram estudados 21 pacientes, com idade média de 47,5 (23-72) anos, sendo 19 (90,4 por cento) do sexo feminino. Empregou-se manometria anorretal com cateter de oito canais dispostos no eixo axial, realizando-se as medidas na porção proximal (1) e distal (2) do canal anal. Todos os pacientes apresentavam elevação dos valores pressóricos em relação ao repouso com esforço de evacuação e para a avaliação do grau de constipação, empregou-se o escore de Agachan. As variáveis estudadas foram: pressão anal média do canal anal por 20 segundos em repouso, ao esforço de evacuação com manobra de Valsalva (V) e ao esforço de evacuação em apneia após expiração forçada (A), assim como a área sob a curva do traçado manométrico nos momentos V e A. RESULTADOS: A análise dos valores médios da variação da pressão anal de repouso evidenciou diferença entre os canais proximais e distais (P = 0,007), independente do momento, e tendência à diferença nos momentos V e A (P = 0,06). A média dos valores da área sob a curva do traçado manométrico demonstrou diferença entre os momentos V e A (P = 0,0008), tanto na porção proximal como na porção distal do canal anal. CONCLUSÃO: O esforço de evacuação associado à apneia pós-expiração quando comparada ao esforço de evacuação associado à manobra de Valsalva, proporciona menor contração do canal anal pela análise do parâmetro área sob a curva.

Complicaciones de la anestesia general con ventilación espontánea (AGCVE) en pacientes quemados / Complications of general anesthesia with spontaneous ventilation (GAWSV) in burn patients

Introducción: La variedad de cambios del medio interno y las abundantes alteraciones que ocurren en los órganos y sistemas de los pacientes quemados hacen que el mantenimiento de la anestesia sea un trabajo complejo. El tratamiento quirúrgico (curación, escarectomía o injerto de piel) se realiza generalmente día por medio y puede extenderse durante muchos meses en casos de necesidad; o sea, se efectúa una gran cantidad de actos anestésicos en poco tiempo. Hace ya mucho tiempo que en el Instituto del Quemado de Córdoba se opta por la anestesia general con ventilación espontánea para evitar realizar tantas intubaciones seguidas y porque las máscaras laríngeas no suelen ser adecuadas para estos pacientes. Objetivo: Evaluar la actual conducta anestésica de los pacientes quemados midiendo la frecuencia de episodios de dolor, de desaturación y de despertar prolongado. Material y métodos: Estudio observacional prospectivo de corte transversal. Se analizaron 40 actos anestésicos en pacientes quemados ASA 2-3 sometidos a cirugía programada, y se registraron los datos de manera observacional directa en una ficha, agrupándolos posteriormente por frecuencia para análisis estadístico. Resultados: Se observaron 29 varones y 11 mujeres entre 19 y 80 años de edad, con un promedio de 38,7 años. El tiempo anestésico total fue de 2075 minutos, promedio aproximado de 51,9 minutos. Se registró un promedio de 3 ± 3,3 episodios de dolor por cirugía, aunque el 45 por ciento presentó solamente entre 1 y 2 episodios de dolor, y el 95 por ciento entre 0 y 6 episodios. El promedio de desaturación por acto anestésico fue de 1 ± 1,074 episodio. El 42,5 por ciento de los actos anestésicos no presentaron apnea - desaturación. Se presentaron 5 episodios de despertar prolongado. Conclusión: Luego del estudio realizado, en el Instituto del Quemado no se registraron importantes complicaciones durante los actos anestésicos... (TRUNCADO)

Introduction: The numerous changes in the internal environment and the many alterations of the organs and systems of burn patients make anesthesia a complex job. Surgical treatment (cures, sloughing, or skin grafts) is generally carried out every second day and can extend for many months in case of need, which means a large number of anesthetic acts in a short time. For a long time now, the Instituto del Quemado de Córdoba (Cordoba Burn Institute) has opted in favor of general anesthesia with spontaneous ventilation in order to avoid so many intubations in a short time span and also because laryngeal masks are usually inadequate for these patients. Objective: To evaluate the current anesthetic conduct in burn patients, measuring the frequency of episodes of pain, desaturation and prolonged awakening. Material and methods: Prospective cross-section observational study. Forty anesthesias in ASA 2-3 burn patients subjected to programmed surgery; data from direct observation was recorded and later grouped by frequency for statistical analysis. Results: Twenty-nine male and 11 female patients were studied, aged between 19 and 80 years, averaging 38.7 years. Total anesthesia time was 2075 minutes, with an approximate average of 51.9 minutes. An average of 3 ± 3.3 pain episodes due to surgery was recorded, although 45 percent only suffered between 1 and 2 episodes of pain and 95 percent had between 0 and 6 episodes. The average of desaturation due to anesthesia was 1 ± 1.074 episodes. 42.5 percent of the anesthesias did not show apnea – desaturation. Five episodes of prolonged awakening were recorded. Conclusion: No important complications during anesthesia were recorded at the Instituto del Quemado. 45 percent of the patients had between 1 and 2 pain episodes due to anesthesia and 42.5 percent did not suffer any apnea - desaturation episodes. GAWSV appears to be an adequate anesthesia option for this type of patients.

Introdução: A variedade de mudanças do meio interno e o grande número de alterações que ocorrem nos órgãos e sistemas dos pacientes queimados tornam a manutenção da anestesia um trabalho complexo. O tratamento cirúrgico (cura, escarectomia ou enxerto de pele) é geralmente feito a cada dois dias, e em caso de necessidade pode se prolongar durante vários meses; ou seja, é preciso realizar muitos atos anestésicos em pouco tempo. Para não realizar tantas intubações seguidas e porque as máscaras laríngeas são habitualmente pouco adequadas neste tipo de pacientes, já há muito tempo que no Instituto del Quemado de Córdoba vem sendo utilizada a anestesia geral com ventilação espontânea. Objetivo: Avaliar a atual conduta anestésica dos pacientes queimados medindo a frequência de episódios de dor, de dessaturação e de acordar prolongado. Material e métodos: Estudo observacional prospectivo de corte transversal. Foram analisados 40 atos anestésicos em pacientes queimados ASA 2-3 submetidos a cirurgia programada. Utilizando uma metodologia observacional direta, registraram-se os dados em una ficha, que posteriormente se agruparam por frequência para análise estatística. Resultados: Foram observados 29 homens e 11 mulheres de entre 19 e 80 anos de idade, média de 38,7 anos. O tempo anestésico total foi de 2075 minutos, média aproximada de 51,9 minutos. Os episódios de dor por cirurgia foram, em média, de 3 ± 3,3, mas em 45 por cento dos casos foram apenas de 1 a 2, e em 95 por cento de 0 a 6. A média de dessaturação por ato anestésico foi de 1 ± 1,074 episódio. Em 42,5 por cento dos atos anestésicos não se registraram eventos de apneia-dessaturação. Os casos de acordar prolongado foram 5. Conclusão: Depois do estudo realizado, não foram registradas no Instituto del Quemado complicações importantes durante os atos anestésicos... (TRUNCADO)

Cardiovascular effects of a novel synthetic analogue of naturally occurring piperamides.

Cardiovascular responses to intravenous administration of a piperamide analogue, LASSBio 365, were investigated in anesthetized rats. LASSBio 365 [62.5-1000 microg/kg, intravenously (IV)] has potent cardiovascular effects that include hypotension and bradycardia, accompanied by a brief pressor effect and apnea. Bilateral vagotomy or atropine injection (2 mg/kg, IV) completely abolished the bradycardia. A drop in blood pressure was abolished in bivagotomized rats. However, it was only inhibited in atropine-treated rats. The apnea was inhibited by both treatments. The Bezold-Jarisch reflex (ie, hypotension, bradycardia, and apnea) induced by LASSBio 365 is altered neither by 5-HT3 antagonist (tropisetron, 0.1 mg/kg, intraarterially) nor by the P2x antagonist (PPADS, 8.6 mg/kg, IV). The pressor component was affected neither by any of these interventions nor by the 5-HT2 antagonist (ritanserin, 0.5 mg/kg, i.a.). In capsaicin-pretreated rats (50 mg/kg, subcutaneously), all responses evoked by LASSBio 365 were abolished, including the pressor effect, which was inhibited. The data show that LASSBio 365 evokes the Bezold-Jarish reflex, neither via serotonergic receptors nor purinergic receptors but perhaps via the vanilloid pathway.

Development of an apnea detector for neonates using diaphragmatic surface electromyography.

Respiratory diseases are among the most important and serious conditions that can affect the newborn baby. A cessation of breathing, longer than 15 seconds, or accompanied by hypoxia or bradycardia, is called apnea of prematurity (AOP) and has been found in more than 50% of premature infants. An apnea detector used in infant monitoring has been designed and constructed and is intended to be applied in a clinical environment. Diaphragmatic surface EMG has been used as the technique for detecting apnea episodes due to a direct relation with the respiratory drive. Both obstructive and central apnea can be determined as well as heart rate. Good performance and feasibility have been shown by the prototype.

Apnea-associated reduction in lower esophageal sphincter tone in premature infants.

OBJECTIVE: To characterize esophageal motility during episodes of prolonged apnea in premature infants. STUDY DESIGN: We retrospectively reviewed combined manometric and physiological monitoring studies performed in tube-fed premature infants from 1994 to 2002. Apnea was defined as a respiratory pause of >20 seconds. For each apneic event, pharyngeal swallowing, esophageal motility, and lower esophageal sphincter (LES) pressure were assessed before, during, and after apneic episodes. RESULTS: Twelve episodes of apnea (duration, 20 to 120 seconds) were identified in 7 infants (34 to 37 weeks postmenstrual age (PMA); study weight, 1950 to 2380 g). During the apneic episodes, swallowing increased (median[interquartile range], 0[0,0], 5[4,7], and 1[0,2] swallows/minute before, during, and after apnea, respectively; P < .05), esophageal pressure wave sequences (PWS) increased (1[0,2], 5[3,6], and 2[1,3] PWS/minute before, during, and after apnea, respectively; P < .05) and LES pressure decreased (16[12,21], 6[5,8], and 27[12,32] mmHg before, during, and after apnea, respectively; P < .05). CONCLUSION: In premature infants, apnea is associated with reduced LES tone, potentially increasing the likelihood of reflux occurring after the onset of apnea.

Primary immunization of premature infants with gestational age <35 weeks: cardiorespiratory complications and C-reactive protein responses associated with administration of single and multiple separate vaccines simultaneously.

OBJECTIVE: To determine the incidence of cardiorespiratory events and abnormal C-reactive protein (CRP) level associated with administration of a single vaccine or multiple separate vaccines simultaneously. STUDY DESIGN: Prospective observational study on 239 preterm infants at > or =2 months of age in the neonatal intensive care unit (NICU). Each infant received either a single vaccine or multiple vaccines on one day. CRP levels and cardiorespiratory manifestations were monitored for 3 days following immunization. RESULTS: Abnormal elevation of CRP level occurred in 85% of infants administered multiple vaccines and up to 70% of those given a single vaccine. Overall, 16% of infants had vaccine-associated cardiorespiratory events within 48 hours postimmunization. In logistic regression analysis, abnormal CRP values were associated with multiple vaccines (OR, 15.77; 95% CI 5.10-48.77) and severe intraventricular hemorrhage (IVH) (OR, 2.28; 95% CI 1.02-5.13). Cardiorespiratory events were associated marginally with receipt of multiple injections (OR, 3.62; 95% CI 0.99-13.25) and significantly with gastroesophageal reflux (GER) (OR, 4.76; 95% CI 1.22-18.52). CONCLUSION: CRP level is expected to be elevated in the 48 hours following immunization. In a minority of infants immunized, cardiorespiratory events were associated with presumed need for intervention. Underlying medical conditions and possibly multiple injections are associated with cardiorespiratory events. Precautionary monitoring following immunizations is warranted.