Within-season influenza vaccine waning suggests potential net benefits to delayed vaccination in older adults in the United States.

BACKGROUND: There is growing evidence that there is within (intra-) season waning of influenza vaccine protection in older adults, suggesting there may be a benefit to giving influenza vaccine closer to the time of increased infection risk. We aimed to quantitatively evaluate the impact of modifying the timing of influenza vaccination in U.S. older adults. METHODS: Using historical data (2010/2011-2015/2016, inclusive) on influenza activity and vaccine uptake, we explore the optimal time to begin vaccinating older adults (≥65 years) in the U.S. to maximize prevention of influenza. We modelled the effect of changing the timing of vaccination by estimating the percentage change to the current disease burden and used this to calculate the estimated optimal week to begin vaccination in the U.S. RESULTS: When we assumed a relatively slower waning protection rate (over 52 weeks), the estimated optimal time to begin vaccinating those aged ≥65 years varied between mid-August (week 34, 2012-2013) and mid-late October (week 43, 2011-2012) depending on the season, resulting in 0.44% and 5.11% of the current disease burden prevented respectively. Under faster waning (over 26 weeks), the estimated optimal week varied between early September (week 37, 2012-2013) and mid-November (week 47, 2011-2012), resulting in 3.69% and 11.97% of the current disease burden prevented respectively. CONCLUSIONS: While it is difficult to determine the ideal time to start to vaccinate due to substantial variation in timing of individual seasons, we found that there are potentially substantial benefits to minimizing the time between vaccination and influenza activity in U.S. older adults. Modest delays in immunization were beneficial in the seasons we evaluated. If further evidence suggests fast waning, longer delays may be warrant as in these scenarios the timing of the current vaccination was often very suboptimal.

Evidence of a salt refuge: chytrid infection loads are suppressed in hosts exposed to salt.

With the incidence of emerging infectious diseases on the rise, it is becoming increasingly important to identify refuge areas that protect hosts from pathogens and therefore prevent population declines. For the chytrid fungus Batrachochytrium dendrobatidis, temperature and humidity refuge areas for amphibian hosts exist but are difficult to manipulate. Other environmental features that may affect the outcome of infection include water quality, drying regimes, abundance of alternate hosts and isolation from other hosts. We identified relationships between water bodies with these features and infection levels in the free-living hosts inhabiting them. Where significant relationships were identified, we used a series of controlled experiments to test for causation. Infection loads were negatively correlated with the salt concentration of the aquatic habitat and the degree of water level fluctuation and positively correlated with fish abundance. However, only the relationship with salt was confirmed experimentally. Free-living hosts inhabiting water bodies with mean salinities of up to 3.5 ppt had lower infection loads than those exposed to less salt. The experiment confirmed that exposure to sodium chloride concentrations >2 ppt significantly reduced host infection loads compared to no exposure (0 ppt). These results suggest that the exposure of amphibians to salt concentrations found naturally in lentic habitats may be responsible for the persistence of some susceptible species in the presence of B. dendrobatidis. By manipulating the salinity of water bodies, it may be possible to create refuges for declining amphibians, thus allowing them to be reintroduced to their former ranges.

Efficacy of SYBR 14/propidium iodide viability stain for the amphibian chytrid fungus Batrachochytrium dendrobatidis.

The amphibian chytrid fungus Batrachochytrium dendrobatidis is a recently described pathogen that has been implicated as a causal agent in the global decline in amphibians. Research into its biology and epidemiology has frequently involved in vitro experimentation. However, this research is currently limited by the inability to differentiate between viable and inviable zoospores. Stains are frequently used to determine cell viability, and this study tested a 2-colour fluorescence assay for the detection and quantification of viable B. dendrobatidis zoospores. The results show that the nucleic acid stains SYBR 14 and propidium iodide are effective in distinguishing live from dead zoospores, and a protocol has been optimized for their use. This viability assay provides an efficient and reliable tool that will have applications in B. dendrobatidis challenge and amphibian exposure experiments.

Is couple therapy indicated for borderline personality disorder?

The healing aspects of intimate relationships are being recognized by therapists and supported by empirical findings. Little has been written regarding the indications for couple therapy for individuals with borderline personality disorder. This paper proposes a three-level hierarchy for deciding on the suitability of couple therapy for patients with borderline personality disorder. The hierarchy is based on three separate borderline behavioral clusters--impulsive, identity, and affective--that should be utilized to direct the application of couple therapy to specific patients. The three levels are illustrated by case examples. Delineation of the indications for couple therapy for borderline patients will foster further theoretical and empirical work in the area.

Respiratory failure due to the combined effects of transdermal fentanyl and epidural bupivacaine/diamorphine following radical nephrectomy.

The transdermal therapeutic system (TTS) fentanyl has been designed for rate-controlled drug delivery. When the system is applied, a fentanyl depot concentrates in the upper skin layers. Plasma concentrations are not measurable until 2 hours after application, and it takes an 8-16 hr latency period until full clinical fentany effects are observed. Following removal, serum fentanyl concentrations decline gradually and fall to about 50% in approximately 16 hours. We report the case of a 77-year-old man with a history of severe arthritis, who was receiving transdermal fentanyl and developed respiratory failure after starting epidural diamorphine/bupivacaine for postoperative pain relief following radical nephrectomy.

Long-term follow-up of Griggs percutaneous tracheostomy with spiral CT and questionnaire.

OBJECTIVE: To assess late complications following percutaneous tracheostomy using the Griggs technique. DESIGN: Observational cohort study SETTING: General ICU of a 700-bed district general hospital in the United Kingdom. PATIENTS: Twenty-five patients who underwent Griggs tracheostomy in the ICU and survived for at least 6 months after decannulation. INTERVENTION: Patients were invited to attend for assessment by questionnaire and for spiral CT of the trachea. RESULTS: Eight patients had moderate tracheal dilatation, two patients were permanently hoarse, nine patients had minor voice changes, no patient had tracheal stenosis, and no patient had a disfiguring scar. CONCLUSION: Following Griggs percutaneous tracheostomy, 8 of 25 patients developed moderate tracheal dilatation, and none developed a tracheal stenosis. The cosmetic result after Griggs tracheostomy is good, but the number of patients with minor voice changes is high. A further investigation of long-term outcome following Griggs tracheostomy is necessary.

Ventilatory response to helium-oxygen breathing during exercise: effect of airway anesthesia.

The substitution of a normoxic helium mixture (HeO2) for room air (Air) during exercise results in a sustained hyperventilation, which is present even in the first breath. We hypothesized that this response is dependent on intact airway afferents; if so, airway anesthesia (Anesthesia) should affect this response. Anesthesia was administered to the upper airways by topical application and to lower central airways by aerosol inhalation and was confirmed to be effective for over 15 min. Subjects performed constant work-rate exercise (CWE) at 69 +/- 2 (SE) % maximal work rate on a cycle ergometer on three separate days: twice after saline inhalation (days 1 and 3) and once after Anesthesia (day 2). CWE commenced after a brief warm-up, with subjects breathing Air for the first 5 min (Air-1), HeO2 for the next 3 min, and Air again until the end of CWE (Air-2). The resistance of the breathing circuit was matched for Air and HeO2. Breathing HeO2 resulted in a small but significant increase in minute ventilation (VI) and decrease in alveolar PCO2 in both the Saline (average of 2 saline tests; not significant) and Anesthesia tests. Although Anesthesia had no effect on the sustained hyperventilatory response to HeO2 breathing, the VI transients within the first six breaths of HeO2 were significantly attenuated with Anesthesia. We conclude that the VI response to HeO2 is not simply due to a reduction in external tubing resistance and that, in humans, airway afferents mediate the transient but not the sustained hyperventilatory response to HeO2 breathing during exercise.

Airway anesthesia and respiratory adaptations to dead space loading and exercise.

In exercising humans, added external dead space (VD) increases minute ventilation (VI) and causes a slower and deeper breathing pattern (J. Appl. Physiol. 1991; 70:55-62). Recent studies suggest that airway receptors sensitive to topical anesthesia influence VI and breathing pattern responses to exercise and to added VD. We tested these hypotheses with a technique of airway anesthesia (Anesthesia) that has been shown to reliably attenuate airway reflexes. Anesthesia was administered by local laryngopharyngeal application and aerosolized lidocaine inhalation, and was confirmed by citric acid aerosol inhalation challenges. Twelve normal males performed maximal incremental cycle ergometer exercise on 4 d (randomized) after Anesthesia with (Anesthesia VD) and without added VD (Anesthesia Control) and after normal saline inhalation (Saline) with (Saline VD) and without added VD (Saline Control). There were no differences in the VI and breathing pattern responses during exercise between the Saline Control and the Anesthesia Control tests. After both Saline and Anesthesia inhalation, added VD resulted in an increase in VI both at rest and during exercise. At matched VI (98 L/min), the differences in tidal volume (VT) between the Saline Control and Saline VD tests (delta = 0.23 +/- 0.24 L, mean +/- SD) and the Anesthesia Control and Anesthesia VD tests (delta = 0.20 +/- 0.28 L) were not significantly different. Our study had a power of greater than 95% to detect significant differences in VI or breathing pattern due to Anesthesia. We conclude that in normal humans, airway receptors do not play a major role in ventilation and breathing pattern control during exercise, and that the respiratory adaptations to added VD during exercise are not mediated by airway afferent reflexes.

Superior laryngeal nerve blockade and inspiratory resistive load detection in normal subjects.

The site for detection of added inspiratory resistive loads is unknown, but recent evidence suggests that the airways may play an important role. The aim of this study was to discern whether the larynx has an important independent role in conscious detection of added inspiratory resistive loads. A randomized double-blind placebo-controlled study of the effect of superior laryngeal nerve blockade on inspiratory resistive load-detection threshold was carried out in 12 normal subjects (7 women; mean age 27.5 yr; range 18-45 yr). Baseline (preinjection) detection thresholds were similar on the lidocaine [0.58 +/- 0.16 (SE) cmH2O.l-1.s] and saline (0.53 +/- 0.12 cmH2O.l-1.s; P = 0.28) days. There was no significant difference in load-detection thresholds after injection between lidocaine (0.60 +/- 0.15 cmH2O.l-1.s) and saline (0.55 +/- 0.10 cmH2O.l-1.s; P = 0.68). Thus, the larynx does not appear to be an important independent airway site for conscious inspiratory resistive load detection.

Superior laryngeal nerve block: an anatomical study.

Superior laryngeal nerve anaesthesia is frequently used to facilitate endotracheal intubation in the awake patient. We have modified the transcutaneous approach to this nerve block to employ a short bevel needle. This improves tactile perception in performing the procedure thus simplifying identification of the correct depth of injection. This study was designed to determine the anatomical basis of superior laryngeal nerve anaesthesia and to estimate the success rate using our modified technique. At autopsy, 20 cadavers had nerve block performed substituting 0.02% methylene blue for local anaesthetic. Dissection was then performed to identify the anatomical structures stained by the simulated local anaesthetic. Additional dissections were performed in formalin-fixed cadavers. We found that the dye was injected into the paraglottic space bounded laterally by the thyrohyoid membrane and thyroid cartilage, medially by the laryngeal submucosa, caudad by the conus elasticus, cephalad by the hyoid bone, and anteriorly and posteriorly by the anterior and posterior thyrohyoid ligaments, respectively. The internal laryngeal nerve, the sensory branch of the superior laryngeal nerve, passed through this compartment and was heavily stained with simulated local anaesthetic. Resistance to the passage of the short bevel needle was provided by the lateral glossoepiglottic fold, not the thyrohyoid membrane as we had expected. Of 40 injections, 39 were deemed successful for a success rate of 97.5%. We conclude that this is a simple and highly successful technique for performing superior laryngeal nerve anaesthesia.

An innovative model of system-linked community care: home-based traction as an alternative to institutional treatment.

Home-based traction is an alternative treatment to conventional hospital-based traction for children with orthopedic conditions such as congenital dislocated hip and Legg-Perthes disease. The application of a proposed theoretical model is used to describe the process of the home-based traction innovation. Creativity and innovation occasions a reconceptualization of stresses. The reconceptualization of stress, plus the operational support of coordinated in-home services, can help families and nurses in the community and in the hospital develop, implement, and evaluate this kind of innovative care. In applying the home-based traction professionals empower and legitimize parents as resourceful co-providers of care. The legitimizing of the alternative in-home service affords parents a more optimistic appraisal of their situation as manageable. Parents are free to develop a coordinated response to their overall circumstance, including the treatment of their one child's illness. The evaluation of this home-based traction example found the alternative to be acceptable, safe, effective in accomplishing treatment goals, and less expensive than conventional hospital-based traction.

Lack of importance of the superior laryngeal nerves in citric acid cough in humans.

The relative importance of laryngeal afferents in the cough reflex in humans is unknown. This study was designed to investigate the importance of superior laryngeal nerve afferents in the cough reflex induced by inhaled nebulized citric acid in awake humans. Nine healthy volunteers had their cough thresholds to inhaled nebulized citric acid measured after superior laryngeal nerve conduction blockade and after a sham nerve block. Of the nine subjects, four showed no change in cough threshold after superior laryngeal nerve anesthesia, three showed increased cough threshold after nerve block compared with no block, and two showed decreased cough threshold after nerve block. The geometric means of the cough thresholds for the nerve block vs. sham block tests were 16 +/- 13 (SD) and 15 +/- 8% citric acid, respectively. There was no statistically significant difference (Wilcoxon signed-rank test) between the cough thresholds with and without superior laryngeal nerve block (P > 0.05). We conclude that, in the awake human, superior laryngeal nerve afferents do not play a necessary role in initiation of citric acid-induced cough.

Respiratory dysfunction following cardiopulmonary bypass: verification of a non-invasive technique to measure shunt fraction.

Respiratory dysfunction is a well recognized complication of cardiopulmonary bypass. The size of the pulmonary shunt fraction is the best indicator of respiratory dysfunction but its measurement conventionally requires use of a pulmonary artery catheter to measure mixed venous oxygen content. We compared pulmonary shunt fraction, based on a non-invasive technique using a previously described mathematical model, with shunt fraction measured invasively using a pulmonary artery catheter in 22 patients undergoing elective coronary artery surgery. The mean shunt fraction measured by the invasive technique was 19.6 +/- 2.0 (18.8-20.4)% of cardiac output at 24 h (+/- 1 SD and 90% confidence intervals) and 20.9 +/- 2.9 (19.8-22.0)% of cardiac output at 44 h post-surgery. There was good agreement between the two methods of measurement. The mean difference was 0.21 percentage points with 95% confidence interval -0.01 to 0.43. The limits of agreement (-1.17 to 1.59) are small enough to be confident that the non-invasive method can be used to give the same result as that obtained using a pulmonary artery catheter. The values for shunt fractions obtained by the non-invasive technique were 19.7 +/- 2.3 (18.8-20.6)% of cardiac output at 24 h and 20.7 +/- 2.5 (19.7-21.6)% of cardiac output at 44 h. The non-invasive measurement of the shunt fraction provided us with a simple, practical method for following a further ten patients over an extended period of time where prolonged catheterization is impractical.

Colloid solutions in the critically ill. A randomised comparison of albumin and polygeline. 1. Outcome and duration of stay in the intensive care unit.

All patients admitted to an Intensive Care Unit were randomised to receive all volume replacement fluid as either human albumin solution or a synthetic colloid. A total of 475 patients were admitted during the study period. Patients' age, sex, APACHE score and calculated risk of death were assessed on admission. Outcome was assessed as length of Intensive Care stay and mortality. There was no difference between the groups. Subgroups of patients with APACHE score greater than 10, calculated risk of death greater than 50% and length of stay greater than 5 days were also evaluated but not significant differences were found between treatment groups. The use of albumin rather than 3.5% polygeline for volume replacement in the Intensive Care Unit has no influence on outcome.