Pulse pressure variability during hemorrhage and reinfusion in piglets: effects of age and tidal volume

Purpose

The dynamic change in arterial pulse pressure during mechanical ventilation (PPV) predicts fluid responsiveness in adults but may not be applicable to pediatric patients. We compared PPV during hemorrhage and reinfusion in immature vs mature piglets at two clinically relevant tidal volumes (V_T).

Methods

Following Institutional Animal Care Committee approval, we measured hemodynamics and PPV in two groups of piglets, 10-15 kg (immature, n = 9) and 25-30 kg (mature, n = 10), under stable intravenous anesthesia at V_T = 8 and 10 mL·kg^?1. Measurements were taken at baseline, with blood withdrawal in 5 mL·kg^?1 steps up to 30 mL·kg^?1, and during stepwise reinfusion. For each age group and V_T, we constructed receiver operating characteristic (ROC) curves to determine the threshold value that was predictive of fluid responsiveness.

Results

Pulse pressure variability was significantly lower in immature vs mature pigs and at V_T 8 vs V_T 10 at every measurement period. The difference in PPV induced by changing V_T was less in immature animals. Significant areas under the ROC curve were obtained in immature pigs at both V_Ts but in mature animals at V_T 10 alone. A PPV threshold was calculated to be 8.2% at V_T 8 and 10.9% at V_T 10 in immature animals vs 15.9% at V_T 10 in mature animals, but sensitivity and specificity were only 0.7.

Conclusion

Pulse pressure variability values are lower and less sensitive to V_T in immature vs mature pigs. Adult PPV thresholds do not apply to pediatric patients, and a single PPV value representing fluid responsiveness should not be assumed.     

Important drug–drug interactions for treatments that target overactive bladder syndrome

Introduction and hypothesis

Overactive bladder (OAB) is the term used to describe the symptom complex of urinary urgency, usually accompanied by frequency and nocturia, with or without urgency urinary incontinence, in the absence of urinary tract infection or other obvious pathology. It is a common distressing condition that significantly impairs quality of life (QoL). After lifestyle advice and bladder retraining, antimuscarinic drugs are most commonly used to treat OAB.

Methods

The antimuscarinics in common use are all metabolised through differing mechanisms. Therefore, the risk of an enhanced drug effect is increased when the potentially interacting substrates compete for the same metabolic pathways. The aim of this review is to provide an overview on potential drug–drug interactions with special emphasis on high-risk groups and clinically important consequences of these interactions

Results and Conclusion

Knowledge of current important drug interactions is vital whilst prescribing antimuscarinics, particularly in high-risk groups. Novel therapies, such as beta 3 agonists or alternative drug delivery systems, such as the oxybutynin vaginal ring, might provide alternative options where these interactions are unavoidable.     

Psychosexual outcome after labiaplasty: a prospective case-comparison study

Introduction and hypothesis

Our goal was to determine psychosexual outcome after labiaplasty in the long-term with specific measures of genital body image and sexual dysfunction.

Method

We conducted a prospective study with a matched-comparison group of women not wanting labiaplasty. Forty-nine women were compared against a group of 39 women matched for age, sexual orientation, ethnicity, and marital status. The labiaplasty group was assessed before, 3 months after and between 11 and 42 months after surgery. The comparison group was assessed at two time points 3 months apart to control for the passage of time. The primary outcome measure was the Genital Appearance Satisfaction (GAS) scale.

Results

Of the 49 women receiving labiaplasty, 19 (38.8 %) were lost to follow-up but were reassessed clinically. Twenty-four of 25 (96 %) women in the labiaplasty group showed a reliable and clinically significant improvement on the GAS scale 3 months after the procedure; 21/23 (91.3 %) showed an improvement at the long-term follow-up. A large effect size was found for improvements on the GAS scale in the labiaplasty group. Small-effect sizes were found for improvements in sexual functioning. Nine women obtaining labiaplasty met diagnostic criteria for body dysmorphic disorder before the operation; eight lost that diagnosis at the 3-month follow-up; 26 % reported minor side effects.

Conclusions

Labiaplasty is effective in improving genital appearance and sexual satisfaction, but larger studies are required to determine the prevalence of potential side effects.     

Evaluation of two commercially available carbon dioxide sampling nasal cannulae

Our study compared two commercially available carbon dioxide sampling nasal cannulae for efficacy of oxygenation and relationship of end-tidal carbon dioxide (Petco ₂) to arterial carbon dioxide (Paco₂). The two-prong nasal cannula (2PNC) has one prong dedicated to delivering O₂ via one naris and the second prong dedicated to sampling exhaled gases via the other naris. The four-prong nasal cannula (4PNC) delivers O₂ via a prong in each naris, and samples exhaled gases via another set of prongs in each naris. Forty six patients were divided into three groups, which received either 2 (n = 15), 3 (n = 16), or 4(n = 15) L/min O₂, respectively, and were studied sequentially with standard nasal cannula (SNC), the 2PNC, and then the 4PNC. At each O₂ flow rate, Pao₂ was equivalent regardless of whether the SNC, 2PNC, or 4PNC was used. Seventy-four percent (34/46) of the 2PNC and 0% (0/46) of the 4PNCPetco2 values were within ±4 torr of the Paco₂ value. The authors conclude that the 2PNC and 4PNC are equally effective compared with an SNC in oxygenating patients, but thePetco2 measured by the 2PNC provides a superior quantitative estimate of the Paco₂ than that obtained by the 4PNC.     

Offering patients a choice of urinary catheter drainage system

The aim of this article is to promote understanding of the benefits, assessment process and suitability of catheter valves, as a form of urinary drainage for patients. A literature review on the benefits of catheter valves provides the opportunity for an in-depth discussion that compares and contrasts different urinary drainage systems. On the evidence of the literature review, all patients require a holistic assessment which considers a number of factors, and provides the nurse with the essential objective data to ascertain the suitability of the catheter valve. These data can be transferred into an easy step-by-step algorithm to help guide the nurse in making the decision, with the patient, on the most appropriate urinary catheter drainage system.     

Epidemiology of treatment-associated mucosal injury after treatment with newer regimens for lymphoma, breast, lung, or colorectal cancer

Goals of work: Oral and gastrointestinal (GI) mucositis are frequent complications of chemotherapy and radiotherapy for cancer, contributing to not only the morbidity of treatment but its cost as well. The risk associated with specific chemotherapeutic agents, alone and in combination, has been characterized previously. In the current study, we sought to estimate the risk associated with newer regimens for the treatment of non-Hodgkin’s lymphoma (NHL) and common solid tumors. Methods: We reviewed published studies reporting phase II and III clinical trials of dose-dense regimens for breast cancer and NHL, TAC (docetaxel, adriamycin, cyclophosphamide) chemotherapy for breast cancer, and infusional 5-fluorouracil-based regimens for colorectal cancer. Platinum-, gemcitabine-, and taxane-based regimens for lung cancer, either alone or in combination with radiotherapy, were also considered. Using modified meta-analysis methods, we calculated quality-adjusted estimates of the risk for oral and GI mucositis by tumor type and regimen. Case reports are used to emphasize the relevance of the findings for patient care. Main results: Our findings demonstrate that mucosal toxicity remains an important complication of cancer treatment. Moreover, innovations in drug combinations, scheduling, or mode of administration significantly modulate the risk for both oral and GI mucositis. Conclusions: Ongoing review of the clinical trial experience will remain important as newer, targeted agents enter standard clinical practice.     

Nocturnal care interactions with patients in critical care units.

BACKGROUND: Sleep deprivation is common in critically ill patients and may have long-term effects on health outcomes and patients' morbidity. Clustering nocturnal care has been recommended to improve patients' sleep. OBJECTIVES: To (1) examine the frequency, pattern, and types of nocturnal care interactions with patients in 4 critical care units; (2) analyze the relationships among these interactions and patients' variables (age, sex, acuity) and site of admission to the intensive care unit; and (3) analyze the differences in patterns of nocturnal care activities among the 4 units. METHODS: A randomized retrospective review of the medical records of 50 patients was used to record care activities from 7 PM to 7 AM in 4 critical care units. RESULTS: Data consisted of interactions during 147 nights. The mean number of care interactions per night was 42.6 (SD 11.3). Interactions were most frequent at midnight and least frequent at 3 AM. Only 9 uninterrupted periods of 2 to 3 hours were available for sleep (6% of 147 nights studied). Frequency of interactions correlated significantly with patients' acuity scores (r = 0.32, all Ps < .05). A sleep-promoting intervention was documented for only 1 of the 147 nights, and 62% of routine daily baths were provided between 9 PM and 6 AM. CONCLUSIONS: The high frequency of nocturnal care interactions left patients few uninterrupted periods for sleep. Interventions to expand the period around 3 AM when interactions are least common could increase opportunities for sleep.