Vasomotor reactivity in premature neonates at term.

In order to assess the specific sympathetic reactivity in premature infants at term, we designed a study to evaluate the peripheral vasomotor response of such infants when exposed to auditory challenges. Testing was performed in 29 premature neonates at term in both quiet and active sleep during a morning session. Two types of noises were used (click and continuous tones) at three frequencies (250, 1,000 and 6,000 Hz) and at three intensities (60, 85 and 110 dBA). Vasomotor response was studied by analyzing with Mathlab software the variability of the plethysmographic wave of the oxymetric pulse. No behavioral awakening was observed in response to any stimulation. When a tachycardia or a bradycardia reaction to the stimuli was observed, all neonates responded with a vasoconstriction. The global mean of the vasoconstrictive response was 18.45%. The overall ANOVA on the vasomotor response revealed significant effects for sleep stages (t: 1.98; p < 0.05), for frequency (t: 3.3; p < 0.001) and for intensity of noise (t: 3.01; p < 0.03) but no significant response with heart rate variability. From these results, we could conclude that the assessment of the vasomotor response is a very sensitive procedure to determine the reactivity of the autonomic nervous system in neonates, and could be used to study such vegetative responses in other stressful situations with good accuracy.

Influence of incubator humidity on sleep and behaviour of neonates kept at stable body temperature.

UNLABELLED: The influence of incubator air humidity (via passive humidification through use of a water reservoir or via active humidification to 2 and 4 kPa) on sleep and behavioural changes was investigated in 13 neonates. The thermal environment of the incubator was servocontrolled via an interactive device tracking the skin temperature changes of the neonates. Using this servocontrolled skin temperature derivative heating programme, it is believed that an increase in air moisture content (reducing evaporative skin cooling) can be counterbalanced by a fall in neutral air temperature, so as to keep the body thermally constant. This procedure permits the experimental evaluation of the specific effect of air humidity on the thermal equilibrium air temperature and the thermal comfort of neonates without eliciting thermoregulatory mechanisms. Under the experimental conditions, in order to keep body temperature stable an increase in water vapour partial pressure from 1.72 (water reservoir) to 3.99 kPa (produced by a nebulizer) is counterbalanced by a decrease in air temperature of 1.49 degrees C. Within this humidity range, the air temperature must be lowered by 0.05 degrees C when the vapour pressure is increased by 0.08 kPa. The magnitude of this deviation depends on the humidity range and is probably a result of changes in the wetted skin area. CONCLUSION: When body temperature is kept constant, changes in air humidity do not modify sleep, body motility and respiratory and heart rates in neonates.

Humidity control tool for neonatal incubator.

In the first days of life, the daily evaporative loss from premature neonates can reach up to 20% of body mass. Such loss can be reduced by increasing the air humidity inside the incubator. Neither passive humidification nor open loop systems allow high humidity rates to be maintained or easily controlled: at 34 degrees C, the maximum levels vary with the system from 40% to 77% of relative humidity. The skin evaporative exchanges between the neonate and the environment are directly proportional to the water vapour partial pressure difference between the neonate's skin and the air. An active closed loop system has been designed, which permits reliable and accurate control of humidity according to the water vapour partial pressure set, between 1 and 6 kPa, in an air temperature range of 28-39 degrees C. It is characterised by variations of about 0.05 kPa around the set value and a maximum humidification speed of 0.25 kPa min-1. The algorithm is based on optimal control and the dynamic programming principles. Test results place this active system above usual systems for its power, precision and adaptability. It is an exploitable tool in fundamental and clinical research, to precisely study the humidity effects on neonatal comfort and thermo-regulation evolution.

[Hodgkin disease, clinical stages IA-IIB: evaluation of the value of cisplatin. Preliminary results]. / Maladie de Hodgkin, stades cliniques IA-IIB: évaluation de l'intérêt du cisplatine. Résultats préliminaires.

Cisplatinum is highly effective in numerous solid tumors and was evaluated in Hodgkin's disease clinical stages (CS) I/II. Sixty-five patients (43 male, 22 female; median age 25, with 12 patients under 16: CS IA-IIA 41, IB 5, IIB 19) were randomly assigned to one of the following arms (PAF87 protocol): 3 ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine with methylprednisolone) cycles (ABVD arm) or 3 ABVD plus cisplatinum cycles (ABVD-Plt arm) followed by radiotherapy (RT); extended field (40 Gy) RT with a short paraaortic field including the spleen (30 Gy) was then administered in the ABVD arm; extended field (30 Gy) without lombosplenic port prophylaxis. RT was administered in ABVD-Plt arm when patients were in complete remission (CR) after chemotherapy (CT). Median follow-up was 35 months (6-62 months). During CT, 1 patient (ABVD-Plt) died from viral meningo-encephalitis; five patients (1 ABVD, 4 ABVD-Plt) stopped treatment because of emesis, of whom three receiving only 1.5-2.5 (ABVD-Plt) cycles, are still in CR after 13-60 months. Fifty-five patients (27 ABVD-Plt) were in CR after CT. Among the 27 ABVD-Plt patients, all in CR after RT, two died (one from myocardial infarction and one from immunoblastic lymphoma); one patient from the ABVD arm died from gastro-intestinal hemorrhage in 1st CR. No ABVD-Plt patient relapsed; 1 ABVD patient relapsed in non-irradiated area. At five years, actuarial survival/relapse-free survival was 96.1/90% and 88.2/100% for ABVD and ABVD-Plt patients, respectively.