ABSTRACT
Low frequency noises are predominant in neonatal intensive care units (NICUs). Some studies affirm that neonates can perceive noises from 113 Hz, and can therefore be affected by sound sources with high spectral content at low frequencies (e.g., incubator engine, air fan). Other studies suggest that reverberation amplifies noise within incubators. In this paper, the reverberation time (T, T 30) within an incubator with standard dimensions was measured in one-third octave bands. To get reliable results, the T was measured in 15 positions at the neonate's ear height, in a room with low T values (to reduce the influence of the room in the results), using an impulsive sound method. Results show a heterogeneous T distribution at the neonate's ear height, with maximum average T differences between positions of 1.07 s. The highest average T of all microphone positions is 2.27 s at 125 Hz, an extremely high mean value for such a small space. As the frequency of electrical devices in America is 60 Hz, some harmonics lay within the one-third octave band of 125 Hz, and therefore may create a very reverberant and inappropriate acoustic environment within the audible spectrum of neonates. As the acoustic environment of the incubator and the room are coupled, it is expected that the results are higher in the NICUs than in the room where the measurements were conducted, as NICUs are more reverberant. Therefore, it is recommended that the T will be limited in the international standards, and that incubator designers take it into account.
ABSTRACT
The neonatal intensive care unit (NICU) is a very noisy place as compared to the intrauterine environment. To protect the neonate's health, international guidelines suggest avoiding noise levels above 45 dB in NICUs, but this recommendation is not normally met. The incubator acoustic isolation and the acoustic features of the NICU play important roles in determining the noise measured inside the incubator. In this study, the influence of two types of rooms, one with sound-absorbent covering and the other with reverberant surfaces, on the acoustic isolation of a neonatal incubator was evaluated using three acoustic isolation indexes: the level difference, the apparent sound reduction index, and the standardized level difference. Results show that the acoustic isolation of the incubator is very poor, with a level difference below 11 dBA at all frequencies. At 62.5 Hz, the level difference measured in both rooms exhibits a negative value, indicating that the incubator amplifies the noise coming from the NICU. Isolation of the incubator is poor, and the reverberation time (RT) of the containing room influences RT of the incubator, which is consequently higher when the containing room is reverberant; for example, the incubator RT in the reverberant NICU is 0.72 s higher at 500 Hz than that in a room with sound-absorbent covering.
ABSTRACT
This study describes the clinical, parasitological and laboratory findings of four patients who lived in the district of Alto Nanay, Maynas, Loreto, Peru and were infected with Mansonella ozzardi microfilariae. Clinical examinations by ophthalmologists, cardiologists and nephrologists were performed. In case 1, the presence of 2 subcutaneous lumps was the most important finding, one at dorsal level and the other in the lower third of the left leg; in case 2, there was a sensation of tingling or coldness in the legs; in case 3, an associated chronic hepatitis B infection was found, and in case 4, a large lump was detected in the left lumbar region. All 4 patients were infected with Mansonella ozzardi and had eosinophilia, 3 of them in percentages of 20%. The lump found in case 4 was due to a herniation of bowel content. Further clinical studies and an evaluation of the actual pathogenic effect of microfilariae are to be performed. A study of the genetic diversity of filariae in the Peruvian Amazon would also be important.
Subject(s)
Mansonella , Mansonelliasis/diagnosis , Adult , Aged , Animals , Female , Humans , Male , Middle Aged , PeruABSTRACT
El presente estudio describe los hallazgos clínicos, parasitológicos y de laboratorio de cuatro pacientes residentes en el distrito de Alto Nanay, Maynas, Loreto, Perú; infectados con microfilarias de Mansonella ozzardi. La evaluación clínica incluyó las especialidades de oftalmología, cardiología y nefrología. En el caso 1, destaca la presencia de dos tumoraciones subcutáneas, una a nivel dorsal y la otra en el tercio inferior de la pierna izquierda; en el caso 2, la sensación de hormigueo o frío en las piernas; en el caso 3 se encontró asociada una infección crónica por hepatitis B y en el caso 4 una tumoración de gran tamaño en región lumbar izquierda. En los cuatro pacientes se encontró Mansonella ozzardi y eosinofilia, tres presentaron valores mayores a 20%. La tumoración en el caso 4 correspondió a una hernia de contenido intestinal. Es necesario ejecutar más estudios clínicos y evaluar su verdadero efecto patógeno, es también pertinente estudiar la diversidad genética de filarias de la Amazonia peruana.
This study describes the clinical, parasitological and laboratory findings of four patients who lived in the district of Alto Nanay, Maynas, Loreto, Peru and were infected with Mansonella ozzardi microfilariae. Clinical examinations by ophthalmologists, cardiologists and nephrologists were performed. In case 1, the presence of 2 subcutaneous lumps was the most important finding, one at dorsal level and the other in the lower third of the left leg; in case 2, there was a sensation of tingling or coldness in the legs; in case 3, an associated chronic hepatitis B infection was found, and in case 4, a large lump was detected in the left lumbar region. All 4 patients were infected with Mansonella ozzardi and had eosinophilia, 3 of them in percentages of 20%. The lump found in case 4 was due to a herniation of bowel content. Further clinical studies and an evaluation of the actual pathogenic effect of microfilariae are to be performed. A study of the genetic diversity of filariae in the Peruvian Amazon would also be important.
Subject(s)
Adult , Aged , Animals , Female , Humans , Male , Middle Aged , Mansonella , Mansonelliasis/diagnosis , PeruABSTRACT
No disponible
