A perinatal stress calculator for the neonatal intensive care unit: an unobtrusive approach.

OBJECTIVE: Early experience of pain and stress in the neonatal intensive care unit is known to have an effect on the neurodevelopment of the infant. However, an automated method to quantify the procedural pain or perinatal stress in premature patients does not exist. APPROACH: In the current study, EEG and ECG data were collected for more than 3 hours from 136 patients in order to quantify stress exposure. Specifically, features extracted from the EEG and heart-rate variability in both quiet and non-quiet sleep segments were used to develop a subspace linear-discriminant analysis stress classifier. MAIN RESULTS: The main novelty of the study lies in the absence of intrusive methods or pain elicitation protocols to develop the stress classifier. Three main findings can be reported. First, we developed different stress classifiers for the different age groups and stress intensities, obtaining an area under the curve in the range [0.78-0.93] for non-quiet sleep and [0.77-0.96] for quiet sleep. Second, a dysmature EEG was found in patients under stress. Third, an enhanced cortical connectivity and increased brain-heart communication was correlated with a higher stress load, while the autonomic activity did not seem to be associated to stress exposure. SIGNIFICANCE: The results shed a light on the pain and stress processing in preterm neonates, suggesting that software tools to investigate dysmature EEG might be helpful to assess stress load in premature patients. These results could be the foundation to assess the impact of stress on infants' development and to tune preventive care.

The implementation of an apnea-based perinatal stress calculator.

Early life stress in the neonatal intensive care unit (NICU) predisposes premature infants to adverse health outcomes. Although those patients experience frequent apneas and sleep-wake disturbances during their hospital stay, clinicians still rely on clinical scales to assess pain and stress burden. This study addresses the relationship between stress and apneic spells in NICU patients to implement an automatic stress detector. EEG, ECG and SpO2 were recorded from 40 patients for at least 3 hours and the stress burden was assessed using the Leuven Pain Scale. Different logistic regression models were designed to detect the presence or the absence of stress based on the signals reactivity to each apneic spell. The classification shows that stress can be detected with an area under the curve of 0.94 and a misclassification error of 19.23%. These results were obtained via SpO2 dips and EEG regularity. These findings suggest that stress deepens the physiological reaction to apneas, which could ultimately impact the neurological and behavioral development.

Delayed delivery of second twin after chorioamnionitis and abortion of first twin at 21 weeks gestation.

Delayed delivery is a relatively new term used to describe the delivery of one fetus after premature delivery of the first fetus. We describe a case where we used tocolysis and antibiotics to prolong a twin pregnancy for 35 days with excellent fetal outcome, after chorioamnionitis had caused the abortion of the first twin at 21 weeks gestation.

QT interval changes following neck dissection. A stratified prospective study.

Studies from Europe have suggested that neck dissection, especially right radical neck dissection, causes a dangerous prolongation of the QT interval. Sudden cardiac arrest due to QT prolongation has been reported following right radical neck dissection. We investigated the prevalence of QT interval prolongation following neck dissection. Electrocardiogram tracings from 45 patients who underwent different combinations of neck dissection were studied. Preoperative and postoperative tracings were interpreted by a cardiologist blinded to the patient identification of each tracing. There were 28 unilateral neck dissection patients and 17 bilateral neck dissection patients eligible for analysis. There were 7 patients in the classic right radical neck dissection group, and only 3 of these had no neck dissection on the left. Comparisons of preoperative versus postoperative corrected QT interval for all subjects did not indicate a significant change. Stratification by neck dissection type (radical, modified or selective, and carotid artery resection) or by side dissected (left, right, or both) also showed no significant differences. No malignant arrhythmias were encountered. Thus, in contrast to the European experience, our findings show no significant predictable change in the QT interval after any of the combinations of neck dissection. Head and neck surgeons should be aware of the possibility of postoperative QT interval prolongation following neck dissection, although in the absence of other risk factors it appears to be a rare occurrence.

The QT interval following carotid artery resection.

BACKGROUND: Right radical neck dissection has been shown to prolong the QT interval, reportedly caused by surgical trauma to the cervical autonomic system, which may result in malignant ventricular arrhythmias. Carotid artery resection would be expected to be more likely to cause dangerous arrhythmias. METHODS: We prospectively studied eight patients with electrocardiograms before and after carotid resection. Four patients had left-sided procedures and four patients had right-sided procedures. In addition, 11 patients were studied retrospectively. QT intervals were normal in all patients preoperatively. RESULTS: Preoperative corrected QT intervals (QTc) were in the normal range used by our institution for all eight patients in the prospective group. There were no significant QTc changes after either left-sided or right-sided carotid resection. However, the retrospective group did show significant changes in QTc following right carotid resection (n = 5), but not left resection (n = 6). CONCLUSIONS: EKG changes associated with carotid resection may not be uniform and may depend on surgical technique or specific anatomic factors. Controlled prospective studies are needed to confirm the prevalence of QT interval changes in radical neck surgery.

Halothane relaxes previously constricted human epicardial coronary artery segments more than isoflurane.

To compare the vasodilatory effects of isoflurane versus halothane on coronary arteries in vitro, we studied the capacity of isoflurane and halothane to relax resting and previously constricted human coronary artery segments with use of in vitro tension recording. Human epicardial coronary artery segments (1.5-2.0 mm outside diameter) were obtained from hearts excised from recipient patients at time of heart transplantation. The effects of 0.5%, 1.0%, 2.0%, and 3.0% isoflurane or halothane on resting coronary artery segments stretched to their optimal resting tension were determined. Next, after removal of anesthetic from the bathing solution, the segments were constricted with K+ (60 mM), and this contraction was allowed to plateau. The arteries were then again exposed to isoflurane or halothane at 0.5%, 1.0%, 2.0%, and 3.0% concentrations. Isoflurane and halothane had no effect on noncontracted coronary artery segments stretched to their optimal resting tension. Halothane caused significant relaxation of K(+)-induced (60 mM) contractions at 2.0% and 3.0% but not at lower concentrations. Isoflurane did not cause significant relaxation of K(+)-induced (60 mM) contractions at any concentration studied. Our studies indicate that under the conditions studied, isoflurane at clinically relevant concentrations is not a significant coronary dilator.

Halothane relaxes preconstricted small and medium isolated porcine coronary artery segments more than isoflurane.

To compare the putative vasodilatory effects of isoflurane versus halothane on porcine coronary arteries, we studied the capacity of isoflurane and halothane to relax K(+)-constricted (30 mM) small (0.5-1.0 mm outside diameter [OD]) and medium (1.0-1.5 mm OD) porcine coronary arteries with use of in vitro tension recording. We also examined the effect of the dihydropyridine calcium channel agonist BAY K8644 on previously constricted epicardial porcine coronary artery segments in the presence of halothane or isoflurane. Our purpose was to determine (a) whether anesthetic effect on coronary arteries varied with arterial diameter, and (b) whether halothane and isoflurane inhibited BAY K8644-induced contraction of coronary vessels. Small and medium porcine coronary artery segments were constricted with K+ (30 mM) and the resulting contraction was allowed to stabilize. This was followed by exposure to 0.5%, 1.0%, 2.0%, and 3.0% isoflurane or halothane and the resultant tension was again measured. Potassium-induced contractions were significantly relaxed by halothane in small coronary artery segments at 0.5%, 1.0%, 2.0%, and 3.0% and in medium coronary artery segments at 1.0%, 2.0%, and 3.0%. Potassium-induced contractions were significantly reduced by isoflurane only at 3.0% in both small and medium coronary artery segments. Halothane caused significantly more relaxation of both small and medium porcine coronary arteries previously constricted with K+ (30 mM) than did isoflurane. There were no significant differences in coronary artery response to isoflurane or halothane with respect to coronary artery diameter. These experiments indicate that in porcine coronary arteries greater than 0.5 mm OD, studied in vitro after K(+)-induced contraction, isoflurane was not a potent coronary vasodilator.(ABSTRACT TRUNCATED AT 250 WORDS)

Halothane relaxes previously constricted isolated porcine coronary artery segments more than isoflurane.

Coronary vasodilation by halothane and isoflurane were compared using in vitro tension recording. Porcine left anterior descending coronary arterial segments (1.5-2.0 mm o.d.) were constricted with either K+ (30 mM) or prostanoid U44069 (6 X 10(-7) M) in the absence of other drugs or anesthetics. Following stabilization of constriction, arteries were exposed to halothane or isoflurane at 0.5, 1.0, 1.5, 2.0, and 3.0% concentrations. K+ (30 mM) induced constriction was reduced by halothane at 1.5, 2.0, and 3.0% and U44069 (6 X 10(-7) M) induced constriction was reduced at 0.5, 1.0, 1.5, 2.0, and 3.0%. K+ (30 mM) induced constriction was reduced by isoflurane only at 3.0% and U44069 (6 X 10(-7) M) induced constriction was reduced by isoflurane only at 2.0 and 3.0%. U44069 induced constriction was more susceptible than K+ induced constriction to relaxation by halothane or isoflurane. Halothane was more potent than isoflurane as a direct relaxant of porcine epicardial left anterior descending arterial segments previously constricted with K+ (30 mM) or U44069 (6 X 10(-7) M).