Large variations between NICU nurses in predicting nasogastric tube insertion length in a mannequin study.

Aim: To evaluate the inter- and intraindividual variation of predicted nasogastric tube insertion lengths by nurses working in two neonatal intensive care units in the Netherlands, using a mannequin model. Methods: A total of 110 nurses (55 nurses from Center A and 55 from Center B) were asked to predict the nasogastric tube insertion length on a neonatal mannequin. We evaluated the length and prediction method used by the nurses. We also estimated the number of tubes that would have correctly been placed in the stomach of a neonate according to the seize of the mannequin. Results: The mean predicted insertion length of the nasogastric tube was 30.0 cm with an interindividual variation of 12 cm (range 24-36 cm). The mean intraindividual variation was 0.75 cm. The two centers used two different prediction methods in their local guidelines, but overall at least 6 different methods were used by the nurses. We estimated that 77% (85/110) of the tubes would have ended in the body of the mannequins stomach, while 10% (11/110) would have ended in the esophagus and 13% (14/110) would have ended against the stomach lining or in the duodenum. Conclusion: Nurses in two neonatal intensive care units used many different methods which lead to a large interindividual variation in predicted insertion lengths of the nasogastric tubes. Regular evaluations using this mannequin model could lead to more uniformity and reduce the risk of tube misplacement in neonates.

Cardiac biomarkers as indicators of hemodynamic adaptation during postasphyxial hypothermia treatment.

BACKGROUND: Little is known about the effects of hypothermia on the cardiovascular system in term newborns with neonatal encephalopathy. OBJECTIVES: To evaluate whether mild hypothermia for neonatal encephalopathy is cardioprotective as indicated by the cardiac biomarkers cardiac troponin I (cTnI) and B-type natriuretic peptide (BNP). METHODS: This was an observational cohort study of infants treated for perinatal asphyxia. In infants, mild total body hypothermia treatment of 33.5°C during 72 h was initiated (n = 20). Samples of cTnI and BNP were collected before the start of hypothermia, at 24 and 48 h after birth, and after rewarming (84 h). BNP and cTnI values were then compared with BNP and cTnI values of asphyxiated infants not treated with hypothermia (n = 28). RESULTS: No differences were found between the groups in clinical patient characteristics or inotropic support. The hypothermia-treated patients seemed to be clinically more affected (5-min Apgar score, p < 0.05; umbilical artery pH, p = 0.08), but showed similar encephalopathy scores. Significantly lower values for BNP were found in hypothermia- compared to nonhypothermia-treated infants at 48 h and at normothermia after rewarming [144 pmol/l (95-286) vs. 75 pmol/l (45-143), 182 pmol/l (73-341) vs. 43 pmol/l (24-163)]. No differences were found for cTnI concentrations between both groups. CONCLUSIONS: The raised, but similar, cTnI values between hypothermia- and nonhypothermia-treated infants indicate similar myocardial damage in both groups. The lower BNP levels during hypothermia treatment suggest that hypothermia after perinatal asphyxia exerts a beneficial effect on cardiac function.

Left ventricular pressure-volume relationships during normal growth and development in the adult rat--studies in 8- and 50-week-old male Wistar rats.

AIMS: Left ventricular (LV) pressure-volume relations provide relatively load-independent indexes of systolic and diastolic LV function, but few data are available on pressure-volume relations during growth and development in the normal adult heart. Furthermore, to quantify intrinsic ventricular function the indexes should be normalized for heart weight. However, in many studies the indexes are reported in absolute terms, or body weight-correction is used as a surrogate for heart weight-correction. METHODS: We determined pressure-volume relations in young (8-week-old, n = 13) and middle-aged (50-week-old, n = 19) male Wistar rats in relation to their heart and body weights. The animals were anaesthetized and a 2F pressure-conductance catheter was introduced into the LV to measure pressure-volume relations. RESULTS: Heart and body weights were significantly higher in the 50-week-old rats, whereas the heart-to-body weight ratio was significantly lower (2.74 +/- 0.32 vs. 4.41 +/- 0.37 mg g(-1), P < 0.001). Intrinsic systolic function, quantified by the slopes of the end-systolic pressure-volume relation (E(ES)), the dP/dt(MAX) vs. end-diastolic volume relation (S-dP), and the preload recruitable stroke work relation (PRSW), normalized for heart weight, was slightly decreased in the 50-week-old rats (S-dP: -6%, P < 0.004; PRSW: -3%, P < 0.06). Heart weight-corrected diastolic indexes were not significant different. The absolute indexes qualitatively showed the same results, but body-weight corrected pressure-volume indexes showed improved systolic function and significantly depressed diastolic function. CONCLUSIONS: Intrinsic systolic function slightly decreases from the juvenile to the middle-aged period in normal male Wistar rats. Furthermore, correction of pressure-volume indexes for body weight is not an adequate surrogate for heart weight-correction in these animals.

Cisplatin-induced autonomic neuropathy: does it really exist?

The neurotoxic side-effects of cisplatin affect predominantly the large, myelinated fibres of peripheral nerves, leading to a sensory neuropathy. Several reports of cisplatin-associated autonomic neuropathy have been published. Autonomic dysfunction however, is caused by a neuropathy of small unmyelinated nerve fibres. By using the absolute pupil diameter as a parameter of autonomic nervous system function, we studied autonomic neuropathy in the eye of cisplatin-intoxicated rats. In addition, we examined autonomic cardiovascular function by measuring the change in heart rate (HR) and mean arterial blood pressure (MAP) in response to intravenous phenylephrine (PHE) and tyramine (TYR). No significant differences in mean pupil diameter developed in cisplatin-intoxicated rats (n = 12) in the course of 9 weeks (total cumulative dose cisplatin 18 mg/kg) compared with normal controls (n = 9) MANOVA, F1,19 = 0.88, P < 0.36). The PHE- and TYR-induced changes in MAP and HR were virtually the same in cisplatin-intoxicated rats when compared with normal controls. We conclude that cisplatin probably does not cause autonomic dysfunction, at least not in rats, in doses commonly used and which are known to cause a peripheral sensory neuropathy.

Neural influences on the iris of diabetic rats and effect of oculomotor nerve crush.

Using an animal model where the pupil diameter of the eye in anaesthetized and dark-adapted rats serves as a parameter of autonomic function, we studied the functional recovery of the parasympathetic nerve fibres in the oculomotor nerve after a crush lesion in rats with streptozotocin-induced diabetes compared with normal controls. Prior to the crush lesion, diabetic rats develop significantly (P < 0.001) smaller pupils compared with controls, and this occurs early in the course of the diabetes mellitus. As the difference in pupil diameter between control and diabetic rats persists immediately after the crush lesion, when the nervous control of the pupil is entirely due to sympathetic nerves, we suggest that the reduction in pupil diameter is due to a sympathetic neuropathy. Furthermore, we show that the functional recovery of the parasympathetic input to the iris after a crush lesion of the oculomotor nerve is not as good in diabetic rats as it is in normal control rats.

Beneficial effect of an ACTH4-9 analogue on experimentally induced diabetic autonomic neuropathy in the eye of the rat under general anaesthesia.

While peripheral polyneuropathy is a well-known complication in diabetes mellitus, and the subject of a great deal of study, the clinical importance of autonomic diabetic neuropathy is increasingly recognised. Using an animal model, where the pupil diameter of the eye serves as a parameter of autonomic function, we produced an age and weight curve of pupil diameter and studied the development of autonomic neuropathy in rats with streptozotocin-induced diabetes. We show that diabetic rats develop significantly (P < 0.009) smaller pupils compared with controls, most probably due to a defective sympathetic input, caused by sympathetic neuropathy. Treatment with the neurotrophic peptide Org 2766, a synthetic ACTH4-9 analogue, prevents the occurrence of this sympathetic neuropathy, as the pupil diameters in the ACTH4-9 analogue-treated group are significantly (P < 0.05) larger than the pupils of placebo-treated rats, and are comparable to the pupil diameters of the rats in the control group.

Experimentally-induced autonomic neuropathy: beneficial effect of a topical ACTH4-9 analogue on oculomotor nerve regeneration.

Melanocortins, peptides related to corticotropin (ACTH) and melanocyte-stimulating hormone, are known to exert beneficial neurotrophic effects in peripheral sensorimotor neuropathies. This has been demonstrated after both systemic and local administration of the peptides. By photographing the rat's pupil under standardized conditions, the authors have previously shown that systemic administration of a synthetic ACTH4-9 analogue can also be beneficial in autonomic neuropathies. The present study demonstrates that topical application of a synthetic ACTH4-9 analogue incorporated in a two-component fibrin glue enhances the speed of recovery of the parasympathetic nerve fibers in the oculomotor nerve after a crush lesion. This may have implications for future use in neurosurgery.

Experimentally induced autonomic neuropathy: beneficial effect of a systemic ACTH4-9 analogue on oculomotor nerve regeneration.

While the regenerating capacity of peripheral nerves has been the subject of intensive study, little is known about the regenerative capacity of the autonomic nervous system. Using an animal model, where the pupil diameter of the eye in the rat serves as a parameter of autonomic function, we studied whether systemic treatment with the neuropeptide Org 2766, a synthetic ACTH4-9, analogue, facilitates the functional recovery of parasympathetic nerve fibres after transection, and after a crush lesion of the oculomotor nerve. By simply photographing the rat's pupil under standardised conditions, we show that sectioning the oculomotor nerve leads to an immediate mydriasis, followed by spontaneous regeneration in 30 days. Systemic treatment with an ACTH4-9 analogue had no effect on the rate or quality of recovery. However, systemic treatment with an ACTH4-9 analogue after a crush lesion of the oculomotor nerve (spontaneous regeneration time 16 days) did enhance the speed of recovery of the parasympathetic nerve fibres in the oculomotor nerve, especially in the initial stages of regeneration. We conclude that the animal model used in this study is valuable for studying the regenerative capacity of the autonomic nervous system and the influence of neurotrophic peptides on autonomic neuropathies. Evidence is presented that synthetic ACTH4-9 analogue exerts beneficial neurotrophic effects, not only in peripheral sensorimotor neuropathies but also in autonomic neuropathies.

Recurrent brain abscess due to an unexpected foreign body.

We report an exceptional case of a patient with chronic frontal sinusitis complicated by chronic osteomyelitis and a cutaneous fistula. A recurrent brain abscess developed and was only cured after a very unusual wooden retained foreign body was removed at surgery. The hazards of wood as a foreign body are discussed and it is stressed that the possibility of a retained foreign body, even unsuspected, must always be borne in mind.