Adelaide C. Figueiredo

Cheyne-Stokes respiration in patients with congestive heart failure: causes and consequences

Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several factors have been implicated in the genesis of Cheyne-Stokes respiration, including low cardiac output and recurrent hypoxia. The key pathophysiological mechanism triggering Cheyne-Stokes respiration is hyperventilation and low arterial CO2 (PaCO2) that when below the apneic threshold triggers a central apnea. Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control. It is associated with recurrent dips in oxygen saturation and arousals from sleep, with oscillations in blood pressure and heart rate, sympathetic activation and increased risk of ventricular tachycardia. Cheyne-Stokes respiration is an independent marker of poor prognosis and may participate in a vicious cycle, further stressing the failing heart.A respiracao de Cheyne-Stokes e uma forma de respiracao periodica na qual apneias e hipopneias se alternam com periodos de hiperpneias que apresentam um padrao crescendo e decrescendo de volume corrente. Esta revisao enfoca as causa e consequencias da respiracao de Cheyne- Stokes em pacientes com insuficiencia cardiaca congestiva na qual a prevalencia e extremamente alta e varia entre 30 a 50%. Varios fatores foram implicados na genese da respiracao de Cheyne-Stokes, incluindo baixo debito cardiaco e hipoxia recorrente. Hiperventilacao e baixos niveis de CO2 arterial (PaCO2), que quando abaixo do limiar de apneia desencadeiam apneia central sao os mecanismos fisiopatologicos chave na genese da respiracao de Cheyne-Stokes. Hiperventilacao esta associada com congestao pulmonar, e a respiracao de Cheyne-Stokes tem uma tendencia maior de ocorrer durante o sono, quando o centro respiratorio e dependente principalmente do controle quimico. A respiracao de Cheyne-Stokes esta associada a quedas recorrentes da saturacao de oxigenio e ao despertar do sono, com oscilacoes recorrentes na frequencia cardiaca, pressao arterial, aumento da atividade simpatica e risco aumentado de taquicardia ventricular. A respiracao de Cheyne-Stokes e um marcador independente de mau prognostico e provavelmente participa de um ciclo vicioso que contribui para a deterioracao cardiaca.

Evaluation of airway obstruction by nasopharyngoscopy: comparison of the Müller maneuver versus induced sleep

UNLABELLED The use of nasopharyngoscopy during the application of intrathoracic pressure (Müller maneuver) is frequently employed to establish the site of upper airway obstruction. The Müller maneuver, however, is used when the patient is awake and therefore may not correlate with obstruction occurring during sleep. AIM To compare the degree of pharyngeal obstruction in the retropalatal and retroglossal regions during the Müller maneuver versus induced sleep using nasopharyngoscopy. STUDY DESIGN A prospective, case series study. MATERIAL AND METHODS Eight patients (three males, five females), with a mean age of 48.6 +/- 9.2 year, underwent nasopharyngoscopy to assess airway anatomy and function during the Müller maneuver while awake and during sleep induced by drip infusion of Midazolam. RESULTS Retropalatal obstruction was similar during the Müller maneuver and sleep (mean + standard deviation = 3.13 +/- 0.99 and 2.75 +/- 0.46, p= 0.234). Retroglossal obstruction was significantly lower during Müller maneuver compared to sleep (mean + standard deviation 0.63 +/- 1.06 and 2.63 +/- 1.30, respectively, p= 0.005). CONCLUSIONS The sleep inducing method was safe under the monitored conditions of this study, and detected more retroglossal obstruction than the Müller maneuver.

Avaliação da obstrução da via aérea superior através da videonasofaringoscopia: comparação da manobra de Müller com o sono induzido

The use of nasopharyngoscopy during the application of intrathoracic pressure (Muller maneuver) is frequently employed to establish the site of upper airway obstruction. The Muller maneuver, however, is used when the patient is awake and therefore may not correlate with obstruction occurring during sleep. AIM: to compare the degree of pharyngeal obstruction in the retropalatal and retroglossal regions during the Muller maneuver versus induced sleep using nasopharyngoscopy. STUDY DESIGN: A prospective, case series study. MATERIAL AND METHODS: Eight patients (three males, five females), with a mean age of 48.6 +/- 9,2 year, underwent nasopharyngoscopy to assess airway anatomy and funciton during the Muller maneuver while awake and during sleep induced by drip infusion of Midazolam. RESULTS: Retropalatal obstruction was similar during the Muller maneuver and sleep (mean + standard deviation = 3.13 +/- 0.99 and 2.75 +/- 0.46, p= 0.234). Retroglossal obstruction was significantly lower during Muller maneuver compared to sleep (mean + standard deviation 0.63 +/- 1.06 and 2.63 +/- 1.30, respectively, p= 0.005). CONCLUSIONS: The sleep inducing method was safe under the monitored conditions of this study, and detected more retroglossal obstruction than the Muller maneuver.

Comparison of full versus short induced‐sleep polysomnography for the diagnosis of sleep apnea

Polysomnography (PSG) is the gold‐standard method for diagnosing obstructive sleep apnea (OSA). However, the gap between demand and capacity in performing PSG is a major health‐care problem. We sought to validate a short day‐time induced sleep for the diagnosis of OSA.

Efeitos da pressão positiva contínua em vias aéreas sobre os sintomas nasofaríngeos em pacientes com a síndrome da apnéia obstrutiva do sono

BACKGROUND: Nasal and pharyngeal symptoms are common in patients with obstructive sleep apnoea (OSA) treated with nasal continuous positive airway pressure (CPAP). However, these symptoms are common in OSA patients even before the treatment. OBJECTIVE: Determine the impact of nasal CPAP on nasal and pharyngeal symptoms in OSA patients. METHOD: Thirty-five adult patients (28 males), age 54±10 years old, with OSA diagnosed by polissonography. All patients answered to a questionnaire about the presence and quantification of sneezing, rhinorrhea, nasal pruritus, obstruction and bleeding, nasal and pharyngeal dryness. The questionnaire was answered before and after at least three months of CPAP therapy. RESULTS: The apnea-hypopnea index was 50±25 events per hour. Twenty six patients (74%) presented at least one naso-pharingeal symptom before treatment. Nasal obstruction was the most common symptom, being referred by 18 patients (51%). Among the patients that were initially assymptomatic (n=9), 78% developed adverse nasal reactions to CPAP. In contrast, among the patients that presented nasal symptoms before treatment, there was a significant reduction in nasal obstruction, nasal and throat dryness scores as well as nasal bleeding after CPAP therapy. CONCLUSION: Nasal na pharyngeal symptoms are frequent in OSAS patients. CPAP therapy may originate nasal symptoms in patients previously assymptomatic, as well as reduce the intensity of these symptoms in patients that are previously symptomatic.