Local infiltration for postsurgical analgesia following total hip arthroplasty: a comparison of liposomal bupivacaine to traditional bupivacaine

Objective: To assess postsurgical clinical and economic outcomes of patients who received local infiltration containing liposomal bupivacaine versus traditional bupivacaine for pain management following total hip arthroplasty (THA).

Methods: This retrospective study included two groups of consecutive patients undergoing THA. The experimental group received local infiltration with a combination of liposomal bupivacaine, bupivacaine HCl 0.25% with epinephrine 1:200,000, and ketorolac for postsurgical analgesia. The historical control group received the previous standard of care: local infiltration with a combination of bupivacaine HCl 0.25% with epinephrine 1:200,000 and ketorolac. Key outcomes included distance walked, length of stay (LOS), opioid medication use, numeric pain scores, hospital charges, hospital costs, all-cause 30?day readmission rate, and adverse events (AEs). Both unadjusted and adjusted (i.e. age, sex, insurance type, living situation, body mass index, procedure side, and comorbidity) outcomes were compared between the two groups.

Results: The experimental group (n?=?64) demonstrated statistically significant improvement versus the historical control group (n?=?66) in mean distance walked on discharge day (249.2 vs. 180.0 feet; unadjusted p?=?.025, adjusted p?=?.070), mean LOS (2.0 vs. 2.7 days; p?p?=?.002), proportion of patients who used opioid rescue medication on postoperative day (POD) 1 (29.7% vs. 56.1%; p?=?.002, p?=?.003) and POD 2 (7.8% vs. 30.3%; p?=?.001, p?=?.003), mean cumulative area under the curve for pain score on POD 0 (127.6 vs. 292.5; p?p?p?=?.006, both). Among a subgroup of patients with available financial information, mean hospital charges were lower in the experimental group ($43,794 [n?=?24] vs. $48,010 [n?=?66]; p?Conclusions: Infiltration at the surgical site with liposomal bupivacaine was associated with improved postsurgical outcomes when compared with traditional bupivacaine in patients undergoing THA.     

Pitot-tube flowmeter for quantification of airflow during sleep

The gold-standard pneumotachograph is not routinely used to quantify airflow during overnight polysomnography due to the size, weight, bulkiness and discomfort of the equipment that must be worn. To overcome these deficiencies that have precluded the use of a pneumotachograph in routine sleep studies, our group developed a lightweight, low dead space 'pitot flowmeter' (based on pitot-tube principle) for use during sleep. We aimed to examine the characteristics and validate the flowmeter for quantifying airflow and detecting hypopneas during polysomnography by performing a head-to-head comparison with a pneumotachograph. Four experimental paradigms were utilized to determine the technical performance characteristics and the clinical usefulness of the pitot flowmeter in a head-to-head comparison with a pneumotachograph. In each study (1-4), the pitot flowmeter was connected in series with a pneumotachograph under either static flow (flow generator inline or on a face model) or dynamic flow (subject breathing via a polyester face model or on a nasal mask) conditions. The technical characteristics of the pitot flowmeter showed that, (1) the airflow resistance ranged from 0.065 ± 0.002 to 0.279 ± 0.004 cm H(2)O L(-1) s(-1) over the airflow rates of 10 to 50 L min(-1). (2) On the polyester face model there was a linear relationship between airflow as measured by the pitot flowmeter output voltage and the calibrated pneumotachograph signal a (β(1) = 1.08 V L(-1) s(-1); β(0) = 2.45 V). The clinically relevant performance characteristics (hypopnea detection) showed that (3) when the pitot flowmeter was connected via a mask to the human face model, both the sensitivity and specificity for detecting a 50% decrease in peak-to-peak airflow amplitude was 99.2%. When tested in sleeping human subjects, (4) the pitot flowmeter signal displayed 94.5% sensitivity and 91.5% specificity for the detection of 50% peak-to-peak reductions in pneumotachograph-measured airflow. Our data validate the pitot flowmeter for quantification of airflow and detecting breathing reduction during polysomnographic sleep studies. We speculate that quantifying airflow during sleep can differentiate phenotypic traits related to sleep disordered breathing.     

Sex Differences in the Association of Regional Fat Distribution with the Severity of Obstructive Sleep Apnea

Study Objectives:

To describe sex differences in the associations between severity of obstructive sleep apnea (OSA) and measures of obesity in body regions defined using both dual-energy absorptiometry and traditional anthropometric measures in a sleep-clinic sample.

Design:

A prospective case-series observational study.

Setting:

The Western Australian Sleep Health Study operating out of the Sir Charles Gairdner Hospital Sleep Clinic, Perth, Western Australia.

Participants:

Newly referred clinic patients (60 men, 36 women) suspected of having OSA.

Interventions:

N/A

Measurements and Results:

Obstructive sleep apnea severity was defined by apnea-hypopnoea index from laboratory-based overnight polysomnography. Body mass index, neck, waist and hip circumference, neck-to-waist ratio, and waist-to-hip ratio were measured. Dual energy absorptiometry measurements included percentage fat and lean tissue. Multivariate regression models for each sex were developed. In women, percentage of fat in the neck region and body mass index together explained 33% of the variance in apnea-hypopnea index. In men, percentage of fat in the abdominal region and neck-to-waist ratio together accounted for 37% of the variance in apnea-hypopnea index.

Conclusions:

Regional obesity is associated with obstructive sleep apnea severity, although differently in men and women. In women, a direct influence of neck fat on the upper airway patency is implicated. In men, abdominal obesity appears to be the predominant influence. The apnea-hypopnea index was best predicted by a combination of Dual Energy Absorptiometry-measured mass and traditional anthropometric measurements.

Citation:

Simpson L; Mukherjee S; Cooper MN; Ward KL; Lee JD; Fedson AC; Potter J; Hillman Fanzca DR; Eastwood P; Palmer LJ; Kirkness J. Sex differences in the association of regional fat distribution with the severity of obstructive sleep apnea. SLEEP 2010;33(4):467-474     

Participants' perspectives of a multi-component, group-based weight loss programme supplement for cardiac rehabilitation: a qualitative study

Addressing overweight and obesity in people with cardiovascular risk factors is an important aspect of cardiac rehabilitation, but minimal implementation of targeted strategies has occurred. The aim of this study was to describe participants' perspectives of a multi-component, group-based weight loss supplement to cardiac rehabilitation programmes. Four focus groups of participants completing the intervention (n = 16) and maintenance phases (n = 19) of the Healthy Eating and Exercise Lifestyle Program (HEELP) were conducted. Interviews were transcribed and thematically analyzed using an inductive process. The overall theme of participants' responses was that HEELP helped them reprogramme their lifestyle behaviours to achieve weight loss. The programme was unique compared with other weight loss programmes because it was delivered and developed by familiar and expert health professionals who tailored the programme to participants' health status. Themes included the process of recognizing and deciding to make a commitment to managing their weight problem and feeling supported by the group and the staff to do this. Participants valued the group-based structure and the specific tools used in the programme. The programme content and structure provides a framework for the development of supplemental programmes for overweight and obese people at high cardiovascular risk.