Noise levels within the ear and post-nasal space in neonates in intensive care.

BACKGROUND: Noise exposure in neonatal units has long been suspected of being a cause of hearing loss associated with such units. The noise intensity to which the neonate is exposed varies with the type of ventilatory support used. Also, the post-nasal space is an enclosed cavity that is close to the inner ear and an area of turbulent and hence potentially noisy airflow. AIM: To determine noise intensities within the ear and post-nasal space in neonates on different modes of ventilatory support using probe microphones, measures previously not undertaken. METHODS: A portable instrument with a probe microphone was used for the measurements. Three groups of infants were included: (a) those receiving no respiratory support (NS); (b) those receiving conventional ventilation (CV); (c) those receiving continuous positive airways pressure (CPAP) support. RESULTS: The mean in-the-ear noise intensities (at 1 kHz) were 41.7 dB SPL (NS), 39.5 dB SPL (CV), and 55.1 dB SPL (CPAP). The noise intensities in the post-nasal space in those receiving CPAP support were higher than in the other groups, reached mean levels of up to 102 dB SPL at some frequencies, and increased with increasing flow rates. CONCLUSIONS: The most important finding is the high noise intensities in the post-nasal space of those receiving CPAP support. Given the proximity of the post-nasal space to the inner ear, enough noise could be transmitted, especially in infants receiving the higher flow rates, to cause cochlear damage and hence hearing loss. It would therefore be wise, wherever possible, to avoid using the higher flow rates.

A trial of recombinant human granulocyte colony stimulating factor for the treatment of very low birthweight infants with presumed sepsis and neutropenia.

OBJECTIVES: The primary objective was to investigate the safety of recombinant human granulocyte colony stimulating factor (rhG-CSF) for the treatment of very low birthweight infants (VLBW) with sepsis and relative neutropenia, specifically with regard to worsening of respiratory distress and thrombocytopenia and all cause mortality. Secondary objectives were to evaluate duration of ventilation, intensive care, and antibiotic use as markers of efficacy. DESIGN: Neonates (< or = 28 days) in intensive care, with birth weights of 500-1500 g, absolute neutrophil count (ANC) of < or = 5 x 10(9)/l, and clinical evidence of sepsis, were randomly assigned to receive either rhG-CSF (10 microg/kg/day) administered intravenously (n = 13), or placebo (n = 15) for a maximum of 14 days, in addition to standard treatment and antibiotics. All adverse events, oxygenation index, incidence of thrombocytopenia, all cause mortality, duration of ventilation, intensive care and antibiotic treatment, and ANC recovery were compared between the two groups. RESULTS: Adverse events and oxygenation index were not increased by, and thrombocytopenia was not attributable to, treatment with rhG-CSF. At 6 and 12 months postmenstrual age, there were significantly fewer deaths in the group receiving rhG-CSF (1/13 v 7/15; p < or = 0.038). There was a non-significant trend towards a reduction in duration of ventilation, intensive care, and antibiotic use in the rhG-CSF group. There was a significantly more rapid increase in ANC in the rhG-CSF treated babies (p < 0.001). CONCLUSIONS: In a small randomised placebo controlled trial in a highly selected group of neonates, adjuvant treatment with rhG-CSF increased ANC rapidly, and no treatment related adverse events were identified. Mortality at 6 and 12 months postmenstrual age was significantly lower in the treatment group. A large trial investigating efficacy in a similar group of neonates is warranted.

A prospective study of cutaneous nerve injury following long saphenous vein surgery.

OBJECTIVES: The aim of this study was to identify the incidence and distribution of nerve damage in patients undergoing primary venous surgery. METHODS: Patients undergoing primary great saphenous vein surgery between February and November 2003 were enrolled. In all cases the great saphenous vein was 'flush' ligated at the sapheno-femoral junction and stripped to the knee by inversion without using a stripper head; multiple phlebectomies were performed using an Oesch hook. A vascular nurse followed up patients 6 weeks post-operatively. Those reporting altered sensation and/or pain were examined by a doctor to provide an objective assessment of any neurological damage. These patients were again followed up by telephone at 6 and 12 months. RESULTS: Sixty-three limbs from 54 patients were enrolled. Numbness or paraesthesia was identified in 17 (27%) limbs at 6 week follow-up. 11 (17%) limbs were affected below the knee and 7 (11%) limbs were affected at the thigh or groin. One of the limbs was affected above and below the knee. Of these 17 limbs there was resolution in six limbs at 6 months and nine limbs at 12 months. Two patients with persistent nerve lesions regretted undergoing surgery. Patients undergoing bilateral surgery were more likely to report abnormal sensation (chi(2) test, p=0.006). There was no significant difference between the incidence of nerve injury for consultant, SpR or SHO as first operator (chi(2) test, p=0.9). CONCLUSION: This study demonstrates the frequency of nerve injury during primary great saphenous vein surgery. It will be useful for clinicians providing informed consent and may provide a benchmark for comparison with newer techniques.