Compensatory strategies for acquired disorders of memory and planning: differential effects of a paging system for patients with brain injury of traumatic versus cerebrovascular aetiology

BACKGROUND

Previous studies have demonstrated the effectiveness of paging systems in compensating for everyday memory and planning problems after brain injury, including in individuals with traumatic brain injury (TBI).

METHODS

Here, in addition to further analyses of the TBI data from a previous randomised control crossover trial, results are reported from a sub-group of 36 participants with brain injury from cerebrovascular accident (CVA).

RESULTS

Results indicate that, as with the TBI group, the pager was effective. However, the pattern of results following cessation of treatment differed. At a group level, TBI participants demonstrated maintenance of pager-related benefits, whereas CVA participants' performance returned to baseline levels. Comparisons of demographic and neuropsychological characteristics of the groups showed that the CVA group was older, had a shorter interval post-injury, and had poorer executive function than the TBI group. Furthermore, within the TBI group, maintenance was associated with executive functioning, such that executive dysfunction impeded maintenance. This correlation remained after controlling for demographic differences between groups.

CONCLUSIONS

Together, these findings suggest that executive dysfunction may affect treatment-for example, whether or not temporary use of the pager is sufficient to establish a subsequently self-sustaining routine.

Rehabilitation of executive dysfunction following brain injury: “Content-free” cueing improves everyday prospective memory performance

Prospective memory (PM) is often claimed to rely upon executive as well as mnemonic resources. Here, we examined the contribution of executive functions towards PM by providing intermittent support for monitoring processes using "content-free" cues, which carried no direct information regarding the PM task itself. Twenty participants with non-progressive brain injury and PM difficulties received brief training in linking a cue phrase "STOP!" with pausing current activity and reviewing stored goals. The efficacy of this strategy was examined with a PM task requiring participants to make telephone calls to a voicemail service at four set times each day for 10 days. Task content was encoded using errorless learning to minimise retrospective memory-based failures. On five randomly selected days, eight text messages reading simply "STOP!" were sent to participants' mobile telephones, but crucially not within an hour of a target time. Striking improvements in performance were observed on cued days, thus demonstrating a within-subjects experimental modulation of PM performance using cues that carry no information other than by association with participants' stored memory of their intentions. In addition to the theoretical insights, the time course over which the effect was observed constitutes encouraging evidence that such strategies are useful in helping to remediate some negative consequences of executive dysfunction. It is proposed that this benefit results from enhanced efficiency of goal management via increased monitoring of current and future goals, and the steps necessary to achieve them, perhaps compensating for under-functioning fronto-parietal attention systems.

Understanding lesbians' healthcare behaviour: the case of breast self-examination

Lesbians' risk of breast cancer is a much-debated issue in health research because lesbians are believed to be at higher risk of the disease than are heterosexual women. This belief is based upon particular risk factors for breast cancer, which are said to be more prevalent in lesbians; and upon differences in preventive health behaviours: in particular, lesbians are said to be less likely to practise breast self-examination (BSE). This paper presents data collected as part of the UK Lesbians and Healthcare Survey (n = 1066) focusing on lesbians who report never practising BSE (n = 218, 20%) and the explanations they offer for their healthcare behaviours. It identifies six types of explanation for not practising BSE: (i) "I don't know what I'm looking for"; (ii) "I've never got into the habit"; (iii) "I'm frightened in case I find something"; (iv) "I don't think I'm at much risk"; (v) "I'm uncomfortable with my body"; and (vi) "My partner does it for me". These findings are important for increasing understanding of lesbians' healthcare behaviour and for developing health promotion materials relevant to their needs.

Electrical heterogeneity within the ventricular wall

Recent studies have established the presence of three distinct cell types in the ventricular myocardium: epicardial, M and endocardial cells. Epicardial and M cell action potentials differ from endocardial cells with respect to the morphology of phase 1. These cells possess a prominent transient outward current (I(to))-mediated notch responsible for the 'spike and dome' morphology of the epicardial and M cell response. M cells are distinguished from the other cell types in that they display a smaller slowly activating delayed rectifier current (I(Ks)), but a larger late sodium current (late I(Na)) and sodium-calcium exchange current (I(Na-Ca)). These ionic distinctions underlie the longer action potential duration (APD) and steeper APD-rate relationship of the M cell, which is more pronounced in the presence of antiarrhythmic agents with class III actions. The preferential prolongation of the M cell action potential results in the development of a transmural dispersion of repolarization (TDR), which can be estimated from the electrocardiogram (ECG) as the interval between the peak and the end of the T wave (QTpeak-QTend interval). Using the canine arterially perfused ventricular wedge model, transmembrane action potentials of the various cardiac cell types can be correlated to the waveforms of the ECG, providing insight into the cellular etiology of ECG abnormalities. Two congenital syndromes of sudden cardiac death that have been modeled using this technique are the long QT and Brugada syndromes. The long QT syndrome has been linked to 5 gene mutations on chromosomes 3, 7, 11, and 21. Mutations in the cardiac sodium channel SCN5A have been linked to families with a history of the Brugada syndrome. Although the etiologies of these two syndromes are different, lethal arrhythmias in both are thought to arise due to amplification of intrinsic electrical heterogeneities. Similar mechanisms are likely responsible for life-threatening arrhythmias in a variety of other cardiomyopathies ranging from heart failure and hypertrophy, which involve mechanisms similar to those operative in LQTS, to ischemia and infarction, which may involve mechanisms more closely resembling those responsible for the Brugada syndrome.

Estrogen receptors in the normal adult and developing human inner ear and in Turner's syndrome

The influence of estrogens, the female sex hormone, on the ear and hearing is yet not fully investigated, though some studies have suggested that estrogens may influence hearing functions. The presence of estrogen receptors alpha and beta has earlier been shown in the inner ear of mice and rats. The aim of this study was to map possible estrogen receptors in the human inner ear. Inner ear tissue from human adults, aborted human normal fetuses and fetuses with Turner's syndrome were collected. Paraffin embedded sections of adult and fetal inner ears were immunostained with antibodies against estrogen receptors alpha and beta. Estrogen receptor alpha containing cells were found in the adult human inner ear only in the spiral ganglion, and estrogen receptor beta in the stria vascularis solely. The human fetal inner ear tissue from both normal and Turner fetuses showed a very weak staining of estrogen receptor alpha in the spiral ganglion cells, but no specific labeling of the Kölliker's organ of Corti at 13, 14 and 18 weeks of age. No staining of estrogen receptor beta was seen in the fetal inner ear.

Minimizing blood loss in burn surgery

BACKGROUND

Significant blood loss continues to plague early tangential excision of the burn wound. Although various techniques to reduce intraoperative blood loss have been described, there is an absence of uniformity and consistency in their application. Furthermore, it is unclear whether these techniques compromise intraoperative tissue assessment and wound outcome. The purpose of this study was to evaluate the effects of a comprehensive intraoperative blood conservation strategy on blood loss, transfusion requirements, and wound outcome in burn surgery.

METHODS

An intraoperative blood conservation strategy (CONSV) that included donor site and burn wound adrenaline tumescence, donor site and excised wound topical adrenaline, and limb tourniquets was prospectively evaluated and compared with a historical control group (HIST) where only topical adrenaline and thrombin were applied to donor sites and excised wounds.

RESULTS

Estimated blood loss was reduced from 211 +/- 166 mL per percentage body surface area excised and grafted in the HIST group to 123 +/- 106 mL in the CONSV group (p = 0.02). Similarly, the intraoperative transfusion requirement in the HIST group was reduced from 3.3 +/- 3.1 units per case to 0.1 +/- 0.3 units per case in the CONSV group (p < 0.001). There was no compromise in wound outcome in the CONSV group, which had a mean skin graft take rate of 96 +/- 4.2%.

CONCLUSION

The application of a strict and comprehensive intraoperative blood conservation strategy during burn excision and grafting resulted in a profound reduction in blood loss and transfusion requirements, without compromising wound outcome.

The 2000 Moyer Award. The relevance of base deficits after burn injuries

The relevance of an elevated base deficit (BD) during the fluid resuscitation of a thermally injured patient is not completely understood. After nonthermal trauma, early elevation of the BD represents insufficient cellular perfusion and is ultimately associated with a higher incidence of organ dysfunction and death. However, this relationship has not been completely examined after burn injuries. The purpose of this study was to determine if elevation of the BD during burn resuscitation was associated with potential consequences of malperfusion, such as systemic inflammatory response syndrome, acute respiratory distress syndrome, and multiple organ dysfunction. The records of 72 patients with burn injuries (mean age, 46 +/- 17 years; mean total body surface area burned, 44% +/- 18%) who required fluid resuscitation on admission to an adult regional burn center were analyzed. Patients with a mean BD of less than -6 mmol/L during the first 24 hours were compared with patients with a mean BD of more than -6 mmol/L. Despite adequate resuscitation with good maintenance of urinary output, the patients in the group with a mean BD of less than -6 mmol/L had more florid systemic inflammatory response syndrome (P = .004), had more prevalent acute respiratory distress syndrome (P = .012), and experienced more severe multiple organ dysfunction (P < .001) compared with patients in the group with a mean BD of more than -6 mmol/L. The results suggest that abnormal elevation of the BD after burn injuries represents a malperfusion state, which may not be recognized if only "traditional" parameters, such as UO, are followed. Furthermore, this state appears to be related to the onset of more severe systemic inflammation and organ dysfunction.

The use of inhaled nitric oxide as adjuvant therapy in patients with burn injuries and respiratory failure

Inhaled nitric oxide (NO) is a relatively new modality in the management of acute respiratory distress syndrome. The purpose of this study was to examine our experience with inhaled NO in 10 adult patients with burn injuries and acute respiratory distress syndrome-related oxygenation failure. The patients had a mean age of 50 +/- 19 years and a mean burn size of 41% +/- 20% of the total body surface area. Seven patients died and 3 survived. The survivors and nonsurvivors did not differ with respect to age, burn size, pre-NO ventilator settings, or indices of oxygenation including PaO2, oxygen saturation in arterial blood, PaO2/fraction of inspired oxygen (FIO2) ratio, and alveolar-arterial oxygen tension difference. The concentration of NO administered ranged between 5 ppm and 30 ppm. PaO2, oxygen saturation in arterial blood, and the PaO2/FIO2 ratio increased in all patients. Although it was not statistically significant, survivors tended to have a more vigorous and sustained response than non-survivors; this was best exemplified by the change in PFR. During the first hour of therapy, the PaO2/FIO2 ratio increased from 64.3 +/- 12.7 to 231.8 +/- 154.5 in survivors and from 93.9 +/- 44.0 to 161.5 +/- 81.8 in the nonsurvivors. After 12 hours of therapy, the PaO2/FIO2 ratio was 306.2 +/- 333.7 in the survivors and 178.9 +/- 69.9 in the nonsurvivors. There were no complications associated with the use of inhaled NO. Although a stronger early response to NO seems to occur in survivors, we cannot definitely conclude that the early response pattern is predictive of recovery. Nonetheless, we believe that inhaled NO has a useful role in the treatment of patients with burn injuries and severe acute respiratory distress syndrome-related oxygenation failure.

Recent developments in home total parenteral nutrition

Home parenteral nutrition (HPN) support has been an advancing therapy in the past 30 years. Patients who previously had no options to sustain their lives are now able to live at home, maintain employment, and continue with most daily activities. Although this therapy has been innovative and successful, it requires great financial and professional resources. The expense of HPN makes most patients dependent on third-party payment, and the complications can result in frequent hospitalizations and may be life-threatening. For these reasons, extensive training of the patient and caregivers is necessary. Thorough and time-consuming monitoring by a multidisciplinary team of professionals is also essential. Home care and supply companies offer services that make the process of home TPN easier for the patient and the healthcare team. Advances in the area of home nutrition support are expected to continue as the demand for this therapy rises.

The role of autopsy on patients with burns

Burn center verification requires the use of autopsy as one method of quality assurance in a burn center. Because of the decreasing rates of autopsies worldwide and improved diagnostic accuracy in our critical care units, we tested the hypothesis that autopsy diagnosis would not alter our clinical diagnosis. A chart review of all deaths (N = 94) that occurred during a 6-year period (1989-1994) was performed. The clinical diagnoses from the hospital charts and autopsy reports for the patients were reviewed, and diagnostic discrepancies were classified as class I or class II errors. Class I diagnostic errors might have altered the clinical outcome. Class II errors were attributable to the burn injuries but were believed to have had little impact on the clinical outcome. The overall autopsy rate was 93.6% (n = 88). Clinical diagnostic errors were found in 16 (18%) of 88 patients. Five class I errors were found in 4 patients (4.5%), and 15 class II errors were found in 13 patients (14.7%). Although the rate of potentially serious errors was low (only 4.5% of the patients in this study) postmortem examinations revealed clinical diagnostic errors. The results of this study support the continued use of autopsies as a means of quality assurance, despite our ability to closely monitor our critically ill patients with burns.

ARDS in patients with thermal injury

OBJECTIVE

To determine the time to onset of the adult respiratory distress syndrome (ARDS) in patients with thermal injury requiring mechanical ventilation. Secondarily, to consider the burn-related risk factors, demographics, incidence, and mortality for ARDS in this population.

DESIGN

Retrospective chart review; ARDS defined according to the American-European Consensus Conference and the Lung Injury Severity Score definitions.

SETTING

Regional, tertiary referral, adult burn unit in a university teaching hospital.

PATIENTS AND PARTICIPANTS

Patients with thermal injury requiring mechanical ventilation, admitted between 1 January 1991 and 28 February 1995.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Of 469 consecutive admissions, 126 (26.9%) received intubation and mechanical ventilation. ARDS was defined according to the American-European Consensus and Lung Injury Severity Score (score > 2.5) definitions. The mean time to onset of ARDS from admission to the burn unit was 6.9 +/- 5.2 and 8.2 +/- 10.7 days when defined by the American-European Consensus and Lung Injury Severity Score definitions respectively (p = 0.41). Of the intubated patients, 53.6 and 45.2% developed ARDS according to the American-European Consensus and Lung Injury Severity Score definitions, respectively (p = 0.19). Using multivariate logistic analysis, only age proved to be an independent risk factor for the development of ARDS (p = 0.03), although there was a trend toward an increased incidence of inhalation injury in patients with ARDS. Mortality was not significantly greater (41.8 vs 32.2%) in those with ARDS compared to those without (p = 0.27).

CONCLUSIONS

According to the American-European Consensus Conference and the Lung Injury Severity Score definitions, ARDS is common in the adult burn population and has a delayed onset compared to most critical care populations. We found age to be a major predisposing factor for ARDS.

Nutrition risk screening characteristics of rural older persons: relation to functional limitations and health care charges

This study was intended to characterize a rural population of older persons through nutrition screening and relate screening items to functional limitations and health care charges. There were 5373 participants (2522 males and 2851 females, mean age 71 y) screened over a 22-mo period by using a self-administered questionnaire adapted from the Nutrition Screening Initiative. Height and weight and cholesterol and albumin concentrations were measured, and health care claims data were obtained. The most frequent screening items reported were use of > or = 3 medications (41%) and food group intakes below recommended frequencies (> 50%). There were significant (P < 0.05) sex differences in affirmative responses to screening items and in likelihood of exceeding proposed threshold values for risk status assigned for body mass index (BMI; in kg/m2), albumin, or cholesterol. Overweight status was notable, with one-half of all subjects having BMIs > 27. Stepwise modeling procedures were used to identify screening items with the ability to predict self-reported functional limitation (logistic regression) and monthly average recorded health care charges (linear regression on logged charges). Age > or = 75 y, use of > or = 3 medications, and an albumin concentration < 35.0 g/L were significant predictors of both functional limitation and health care charges. Poor appetite, eating problems, income < $6000/y, eating alone, and depression were significant predictors of functional limitation but not health care charges. Being male, loss of 10 lb (4.5 kg), BMI > 27, cholesterol concentration < 4.14 or > 6.21 mmol/L, and functional limitation were significant predictors of health care charges only. These findings suggest that selected screening items may have be useful in the identification of subjects at potential risk for these outcomes.

Nutrition and health for older persons in rural America: a managed care model

Health care services and resources for older persons living in rural areas may be highly variable, and integrated service-delivery models are often lacking. This article presents a managed-care model of nutrition risk screening and intervention for older persons in rural areas. Nutrition risk screening was implemented by the Geisinger Health Care System, Danville, Pa, to target all eligible enrollees in a regional Medicare risk program. A single remote clinic site participating in the managed health care system was chosen for further study of a linked screening and case-management effort for undernourished persons. Screening and intervention at the clinic site selected for this study were guided by centralized expertise and resources. Individualized evaluation and intervention plans were developed with the aid of a dietitian and implemented by the clinic case manager. Of the 417 subjects who completed screening at the remote site, 68 met the risk criteria for undernutrition and were selected for case management. Many of the targeted persons received interventions that included evaluations by a physician or physician extender (eg, physician assistant, nurse practitioner) at the clinic and consultations with nutrition, mental health, or social services professionals. Twenty-six of the subjects who took part in the intervention completed a follow-up screening 6 months later. Ten of those persons no longer exhibited risk criteria. This demonstrates the feasibility of a linked screening and case management program for nutrition risk in the managed-care setting.

Fibroblast growth factor-2 potentiates vascular smooth muscle cell migration to platelet-derived growth factor: upregulation of alpha2beta1 integrin and disassembly of actin filaments

Fibroblast growth factor-2 (FGF-2) has been implicated in vascular smooth muscle cell (SMC) migration, a key process in vascular disease. We demonstrate here that FGF-2 promotes SMC motility by altering beta1 integrin-mediated interactions with the extracellular matrix (ECM). FGF-2 significantly increased surface expression of alpha2beta1, alpha3beta1, and alpha5beta1 integrins on human SMCs, as assessed by flow cytometry. The greatest increase was for the collagen-binding alpha2beta1 integrin. Despite this, FGF-2 did not increase SMC adhesion to type I collagen but instead promoted SMC elongation and SMC motility. The latter was evaluated by using a microchemotaxis chamber and by digital time-lapse video microscopy. Although FGF-2 was not chemotactic for human SMCs, cells preincubated with FGF-2 displayed a 3.1-fold increase in migration to the undersurface of porous type I collagen-coated membranes and a 2.1-fold increase in migration speed on collagen. Furthermore, chemotaxis to platelet-derived growth factor-BB on collagen was significantly greater in SMCs exposed to FGF-2. FGF-2-induced elongation and migration on collagen were inhibited by a blocking anti-alpha2beta1 antibody; however, SMC adhesion to collagen was unaffected. SMC migration on fibronectin was also enhanced by FGF-2, although less prominently: migration through porous membranes increased 1.8-fold, and migration speed increased 1.3-fold. Also, FGF-2 completely disassembled the smooth muscle alpha-actin-containing stress fiber network contemporaneously with the change in integrin expression and cell shape. We conclude that (1) exogenous FGF-2 promotes SMC migration and potentiates chemotaxis to PDGF-BB; (2) the promigratory effect of FGF-2 is especially prominent on type I collagen and is mediated by upregulation of alpha2beta1 integrin; and (3) FGF-2 disassembles actin stress fibers, which may promote differential utilization of alpha2beta1 integrin for motility but not adhesion. This dynamic SMC-ECM interplay may be an important mechanism by which FGF-2 facilitates SMC motility in vivo.

A prospective randomized study of glutamine-enriched parenteral compared with enteral feeding in postoperative patients

Plasma amino acids were measured in 17 postoperative subjects randomly assigned to receive for > or = 5 d tube feeding or total parenteral nutrition (TPN) that had identical energy, nitrogen, and glutamine contents. Subjects required gastric or pancreatic surgery for malignancy and were well-matched for age and body mass index. Tube feeding or TPN began on postoperative day 1 and advanced in daily 25% increments to meet goals of 105 kJ . kg body wt-1 . d-1, 1.5 g protein . kg body wt-1 . d-1, and 0.3 g glutamine . kg body wt-1 . d-1. Delivered energy, nitrogen, and glutamine were closely matched on day 4. Nitrogen balance and plasma proteins did not differ significantly between feeding groups. Total indispensable amino acids, branched-chain amino acids, and glutamine declined 25% on postoperative day 1 compared with preoperative day 0. Indispensable and branched-chain amino acid concentrations were restored with 5 d of either tube feeding or TPN. Glutamine concentrations did not differ significantly by feeding group, though a trend suggested that glutamine recovered more slowly in the tube-fed than in the TPN-fed subjects. Plasma amino acids otherwise reflected formula composition with ratios of valine to leucine of 1.24 and 3.69 mumol/L in subjects receiving 5 d of tube feeding or TPN, respectively. These findings suggest that glutamine-enriched tube feeding and TPN can result in similar profiles for most plasma amino acids at carefully matched doses.

A double-blind, prospective, randomized study of glutamine-enriched compared with standard peptide-based feeding in critically ill patients

Arterial and venous plasma amino acids were determined in 28 intensive care patients randomly assigned to receive 10 d of isoenergetic, isonitrogenous feedings that differed sixfold in glutamine content. Subjects were generally well-matched for age, injury severity, and disease diagnoses. Nasojejunal feedings were started within 48 h of admission. Data were analyzed from those 19 subjects still receiving > or = 50 mL feeding/h on day 5. Both groups had comparable gastric residuals, stool frequency, and delivered nitrogen and energy. At study initiation, all subjects had relative hypoaminoacidemia, with day 1 venous glutamine concentrations down 26% compared with reference values. Plasma glutamine rose to comparable concentrations with feeding of either diet. There were, however, significant (P < 0.05) increases in arterial or venous plasma total, indispensable, and branched-chain amino acids of 125-144% by day 5 only in patients fed the standard control diet. The phenylalanine-tyrosine ratio was elevated on day 1 in both groups (1.3-1.4) but decreased significantly only in the glutamine-supplemented group (1.1 compared with 1.4) by day 5. Glutamine supplementation blunted the hyperaminoacidemia and elevated aromatic amino acid response to injury.