A randomized trial of 72- versus 24-hour intravenous tubing set changes in newborns receiving lipid therapy.

OBJECTIVE: To compare the microbial contamination rate of infusate in the intravenous tubing of newborns receiving lipid therapy, replacing the intravenous delivery system at 72-hour versus 24-hour intervals. DESIGN: Infants requiring intravenous lipid therapy were randomly assigned to have intravenous sets changed on a 72- or a 24-hour schedule, in a 3:1 ratio, in order to compare the infusate contamination rates in an equivalent number of tubing sets. SETTING: A 35-bed, teaching, referral, neonatal intensive-care unit (NICU). PARTICIPANTS: All neonates admitted to the NICU for whom intravenous lipid was ordered. METHODS: Patients were randomized in pharmacy, on receipt of the order for intravenous lipid therapy, to either 72- or 24-hour administration set changes, and followed until 1 week after discontinuation of lipids or discharge from the NICU. Microbial contamination of the infusate was assessed in both groups at the time of administration set changes. Contamination rates were analyzed separately for the lipid and amino acid-glucose tubing sets. Patient charts were reviewed for clinical and epidemiological data, including birth weight, gestational age, gender, age at start of lipid therapy, duration of parenteral nutrition, and type of intravenous access. RESULTS: During the study period, 1,101 and 1,112 sets were sampled in the 72- and 24-hour groups, respectively. Microbial contamination rates were higher in the 72-hour group than the 24-hour group for lipid infusions (39/1,101 [3.54%] vs 15/1,112 [1.35%]; P=.001) and for amino acid infusions (12/1,093 [1.10%] vs 4/1,103 [0.36%]; P=.076). Logistic regression analysis controlling for birth weight, gestational age, and type of venous access showed that only the tubing change interval was significantly associated with lipid set contaminations (odds ratio, 2.69; P=.0013). The rate of blood cultures ordered was higher in the 72- versus the 24-hour group (6.11 vs 4.99 per 100 patient days of total parenteral nutrition; P=.017), and a higher proportion of infants randomized to the 72-hour group died (8% vs 4%; P=.05), although the excess deaths could not clearly be attributed to bacteremia. CONCLUSION: Microbial contamination of infusion sets is significantly more frequent with 72- than with 24-hour set changes in neonates receiving lipid solutions. This may be associated with an increased mortality rate.     

It's better by day

Day surgery has had a slow record f growth in the UK, despite the benefits it offers. Robert Chapman explains the advantages of planning a dedicated unit.     

Modulation of the cutaneous responsiveness of neurones in the primary somatosensory cortex during conditioned arm movements in the monkey

Summary The present experiments were designed to investigate the neuronal mechanisms, at the level of the primary somatosensory cortex, which underlie the observation that somatosensory cortical potentials evoked by air puff stimuli directed at the forearm are decreased, in a nonspecific and widespread manner, during voluntary movements about the elbow. Unitary discharge was recorded from 131 cells receiving cutaneous input from the hairy skin of the forearm or hand (areas 3b and 1) of two monkeys trained to perform rapid movements of the contralateral arm (elbow flexion or extension). Evoked unitary responses to air puff stimuli applied to the centre of the cell's receptive field, at various delays before and after the onset of movement, were recorded. Movement produced a significant decrease in the short latency excitatory response to the air puff in 89% of the cells (117/131); the remaining 11% were not modulated by movement. This movement-related gating of cutaneous inputs occurred regardless of the response pattern of the cells to movement alone, being observed in 91% of the cells with no movement-related discharge, and 89% of those with movement-related discharge. The air puff responses of cells with inputs from the forearm and the dorsum of the hand were all similarly modulated by movement and the modulation was clearly present prior to the onset of movement (mean onset, -66 ms). Variation in the depth of modulation as a function of the direction of the movement, flexion or extension, was observed in only a very small proportion of the modulated units (16/117); most showed no relationship to direction. It is suggested that, in this experimental situation, much of the modulation appears to occur at a pre-cortical level since there was no relationship between the pattern of discharge of cells in relation to movement alone and the pattern of movement-related gating of their responses to the air puff. Effects which might be consistent with a cortical origin for the modulation were only infrequently observed. The present results are strikingly similar to those obtained using the evoked potential method, and thus support the hypothesis that, in this task of rapid elbow movements, movement modulates the transmission of cutaneous signals from the hairy skin of the distal forelimb to primary somatosensory cortex in a nonspecific and widespread fashion.     

Psychological aspects of postoperative pain control.

This article examines the biological basis of emotional distress during postoperative pain, discussing the causal links between tissue injury and the mechanisms of centrally mediated emotional arousal. Neurologic signals from injured tissues induce spinoreticular transmission and extensive processing in limbic brain. Pain, as an emotion, shares central noradrenergic mechanisms with vigilance, a biologically important process. The emotional dimension of postoperative pain corresponds to perceived threat. Injury-induced activation of central noradrenergic mechanisms equips the patient for "fight or flight" just as in nature it equips a wounded animal for self-preservation actions. Although the brain chemistry of emotion prepares the postoperative patient to undertake some sort of survival-directed activity, most hospital settings do not permit patients to cope for themselves. This biologically mandated need to cope with injury has no avenue for expression. Several basic concepts from clinical psychology apply to the management of patients after surgery: Control, coping and self-efficacy. In light of the psychobiological nature of emotion in postoperative pain, they explain the benefits of therapies that encourage self-control such as patient controlled analgesia (PCA). PCA changes the role of the postoperative patient from passive to active, permitting patients in pain to cope actively for themselves. Moreover, it demonstrates that an integration of technological advances with psychological principles can improve patient satisfaction with care delivery.     

Cutaneous versus Muscular Perception of Electrically Evoked Tetanic Pain

This work was supported in part by Laval University (sabbatical leave of Dr. A.Y. Bélanger), the School of Kinesiology at Simon Fraser University, and Medtronic of Canada Inc. There is much speculation in athletic, physical therapy, and sports medicine circles about the relative cutaneous (superficial) vs. muscular (deep) perception of pain felt during maximum electrically evoked tetanic muscle contraction. To date, very few studies have addressed the basic question of whether pain perception during electrical stimulation is more superficial (cutaneous) or deep in muscular tissue. The purpose of this study was to determine, in a group of 10 healthy male subjects, the effect of a complete sensory nerve block at the thigh on the qualities (intensity, sensory, affective) of pain (elicited by electrically induced tetanic muscle contraction) as measured by the Short-Form McGill Pain Questionnaire felt during high amplitude, 50-Hz electrical stimulation (ES) of the vastus lateralis muscle. The findings from this study provide clear evidence that a healthy individual's tolerance level to pain induced during electrically evoked maximum tetanic muscle contraction depends as much on deep muscle stimulation as it does on cutaneous or superficial stimulation. Indeed, the results show a statistically significant decrease of approximately 50% in all three qualities of pain (intensity, sensory, and affective) following the elimination of cutaneous pain pathways via the nerve blocking procedure (p < 0.05). Until it is demonstrated that the same results hold for patients who often experience pain prior to ES treatments, any clinical implications would seem to be premature. For now, clinicians must be aware that muscle, as much as skin, may limit one's ability to tolerate high amplitude ES treatments. Further research is needed on the cutaneous vs. muscular perception of electrically evoked pain in healthy and diseased populations as well as on the issue of subject and patient experience vs. nonexperience with ES. J Orthop Sports Phys Ther 1992;16(4):162-168.     

Papuloerythroderma. Another case of a new disease

We describe a case of papuloerythroderma. This is a distinctive clinical entity characterized by pruritus, red-brown flat-topped papules exhibiting the "deck-chair" sign, eosinophilia, and lymphopenia. We propose that the Langerhans cell may have a central role in the pathogenesis of papuloerthroderma and we describe an excellent response to photochemotherapy.     

Phase II trial of VP16-213 in non-small cell lung cancer (NSCLC)

Summary Fifty-one patients with non-small cell lung cancer (NSCLC) were treated, during a phase II trial, with 4 demethylepipodophyllotoxin--d-ethylidene glucoside (VP16-213). Forty-nine were evaluable for response, and of these two (4%) had partial responses lasting 5 and 6 months. Prior treatment with chemotherapy may have adversely affected response rate; none of the 24 previously treated patients had a major response. Myelosuppression was the dose limiting toxicity. Anorexia, nausea and vomiting, partial alopecia, and chills plus hypotension during drug infusion were the other toxic effects. We conclude that VP16-213 has only minimal activity as a single agent in NSCLC.Supported in part by NIH Grant No. CA-05826 and CA-09027, and by NCI Contract NO-1-CM 972744Demethylepipodophyllotoxin--d-Ethylidene Glucoside (NSC141540) was supplied by the Drug Evaluation Branch of the National Cancer Institute