Collette Menadue

Reliability of two goniometric methods of measuring active inversion and eversion range of motion at the ankle

BackgroundActive inversion and eversion ankle range of motion (ROM) is widely used to evaluate treatment effect, however the error associated with the available measurement protocols is unknown. This study aimed to establish the reliability of goniometry as used in clinical practice.Methods30 subjects (60 ankles) with a wide variety of ankle conditions participated in this study. Three observers, with different skill levels, measured active inversion and eversion ankle ROM three times on each of two days. Measurements were performed with subjects positioned (a) sitting and (b) prone. Intra-class correlation coefficients (ICC[2,1]) were calculated to determine intra- and inter-observer reliability.ResultsWithin session intra-observer reliability ranged from ICC[2,1] 0.82 to 0.96 and between session intra-observer reliability ranged from ICC[2,1] 0.42 to 0.80. Reliability was similar for the sitting and the prone positions, however, between sessions, inversion measurements were more reliable than eversion measurements. Within session inter-observer measurements in sitting were more reliable than in prone and inversion measurements were more reliable than eversion measurements.ConclusionOur findings show that ankle inversion and eversion ROM can be measured with high to very high reliability by the same observer within sessions and with low to moderate reliability by different observers within a session. The reliability of measures made by the same observer between sessions varies depending on the direction, being low to moderate for eversion measurements and moderate to high for inversion measurements in both positions.

Non‐invasive ventilation during arm exercise and ground walking in patients with chronic hypercapnic respiratory failure

Background and objective:  People with chronic hypercapnic respiratory failure (HRF) often have a ventilatory limitation to exercise with difficulty performing activities of daily living. Although non‐invasive ventilation (NIV) appears to reduce the ventilatory limitation and improve exercise performance in people with severe COPD, the effect of NIV during functional activities such as unsupported arm exercise (UAE) and ground walking in people with chronic HRF is unclear.

Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: a randomised crossover study

Introduction In people with obesity hypoventilation syndrome (OHS), breathing 100% oxygen increases carbon dioxide (PCO2), but its effect on pH is unknown. This study investigated the effects of moderate concentrations of supplemental oxygen on PCO2, pH, minute ventilation (VE) and physiological dead space to tidal volume ratio (VD/VT) among people with stable untreated OHS, with comparison to healthy controls. Methods In a double-blind randomised crossover study, participants breathed oxygen concentrations (FiO2) 0.28 and 0.50, each for 20 min, separated by a 45 min washout period. Arterialised-venous PCO2 (PavCO2) and pH, VE and VD/VT were measured at baseline, then every 5 min. Data were analysed using general linear model analysis. Results 28 participants were recruited (14 OHS, 14 controls). Among OHS participants (mean±SD arterial PCO2 6.7±0.5 kPa; arterial oxygen 8.9±1.4 kPa) FiO2 0.28 and 0.50 maintained oxygen saturation 98–100%. After 20 min of FiO2 0.28, PavCO2 change (ΔPavCO2) was 0.3±0.2 kPa (p=0.013), with minimal change in VE and rises in VD/VT of 1±5% (p=0.012). FiO2 0.50 increased PavCO2 by 0.5±0.4 kPa (p=0.012), induced acidaemia and increased VD/VT by 3±3% (p=0.012). VE fell by 1.2±2.1 L/min within 5 min then recovered individually to varying degrees. A negative correlation between ΔVE and ΔPavCO2 (r=−0.60, p=0.024) suggested that ventilatory responses were the key determinant of PavCO2 rises. Among controls, FiO2 0.28 and 0.50 did not change PavCO2 or pH, but FiO2 0.50 significantly increased VE and VD/VT. Conclusion Commonly used oxygen concentrations caused hypoventilation, PavCO2 rises and acidaemia among people with stable OHS. This highlights the potential dangers of this common intervention in this group.

Clinical Commentary: Obstetric and Respiratory Management of Pregnancy with Severe Spinal Muscular Atrophy

We present a combined obstetric and respiratory perspective on two pregnancies for a woman with severe Type 2 Spinal Muscular Atrophy (SMA). Our patient had the lowest prepregnancy weight (20 kg) and vital capacity of 0.34 L (VC 11% predicted) yet to be reported in the sparse literature on pregnancy with SMA. She delivered two live healthy infants via planned caesarean section without pregnancy or neonatal complication. We describe the respiratory and obstetric management techniques used for a pregnancy with this degree of respiratory compromise.

Bilevel ventilation during exercise in acute on chronic respiratory failure: A preliminary study

To determine the immediate effects of bilevel non-invasive ventilation plus oxygen (NIV+O(2)) during exercise compared to exercise with O(2) alone in people recovering from acute on chronic hypercapnic respiratory failure (HRF), a randomised crossover study with repeated measures was performed. Eighteen participants performed six minute walk tests (6MWT) and 16 participants performed unsupported arm exercise (UAE) tests with NIV+O(2) and with O(2) alone in random order. Distance walked increased by a mean of 43.4m (95% CI 14.1 to 72.8, p=0.006) with NIV+O(2) compared to exercise with O(2) alone. In addition, isotime oxygen saturation increased by a mean of 5% (95% CI 2-7, p=0.001) and isotime dyspnoea was reduced [median 2 (interquartile range (IQR) 1-4) versus 4 (3-5), p=0.028] with NIV+O(2). A statistically significant increase was also observed in UAE endurance time with NIV+O(2) [median 201s (IQR 93-414) versus 157 (90-342), p=0.033], and isotime perceived exertion (arm muscle fatigue) was reduced by a mean of 1.0 on the Borg scale (95% CI -1.9 to -0.1, p=0.037) compared with O(2) alone. Non-invasive ventilation plus O(2) during walking resulted in an immediate improvement in distance walked and oxygen saturation, and a reduction in dyspnoea compared to exercise with O(2) alone in people recovering from acute on chronic HRF. The reduction of dyspnoea during walking and arm muscle fatigue during UAE observed with NIV+O(2) may allow patients to better tolerate exercise early in the recovery period.

High- and low-level pressure support during walking in people with severe kyphoscoliosis

To determine whether the level of pressure support (PS) provided during exercise influences endurance time in people with severe kyphoscoliosis, a double-blind randomised crossover study was performed. We hypothesised that high-level PS would be required to enhance endurance time in this population with high impedance to inflation. 13 participants with severe kyphoscoliosis performed four endurance treadmill tests in random order: unassisted; with sham PS; low-level PS of 10 cmH2O (PS 10); and high-level PS of 20 cmH2O (PS 20). Participants and assessors were blinded to the level of PS delivered during exercise. Endurance time was greater with PS 20 (median (interquartile range) 217 (168–424) s) compared with unassisted exercise (139 (111–189) s), sham PS (103 (88–155) s) and PS 10 (159 (131–206) s). In addition, isotime respiratory rate was decreased by 8 breaths·min−1 (95% CI -11– -5 breaths·min−1) and isotime oxygen saturation increased by 4% (95% CI 1–7%) with PS 20 compared with unassisted exercise. People with severe kyphoscoliosis require high-level PS during walking to improve exercise performance. Investigation of high-level PS as an adjunct to exercise training or to assist in the performance of daily activities is warranted.

Validation of respiratory inductive plethysmography (LifeShirt) in obesity hypoventilation syndrome.

Validation of respiratory inductive plethysmography (LifeShirt system) (RIPLS) for tidal volume (VT), minute ventilation (V˙E), and respiratory frequency (fB) was performed among people with untreated obesity hypoventilation syndrome (OHS) and controls. Measures were obtained simultaneously from RIPLS and a spirometer during two tests, and compared using Bland Altman analysis. Among 13 OHS participants (162 paired measures), RIPLS-spirometer agreement was unacceptable for VT: mean difference (MD) 3 mL (1%); limits of agreement (LOA) -216 to 220 mL (±36%); V˙E MD 0.1 L min(-1) (2%); LOA -4.1 to 4.3 L min(-1) (±36%); and fB: MD 0.2 br min(-1) (2%); LOA -4.6 to 5.0 br min(-1) (±27%). Among 13 controls (197 paired measures), RIPLS-spirometer agreement was acceptable for fB: MD -0.1 br min(-1) (-1%); LOA -1.2 to 1.1 br min(-1) (±12%), but unacceptable for VT: MD 5 mL (1%); LOA -160 to 169 mL (±20%) and V˙E: MD 0.1 L min(-1) (1%); LOA -1.4 to 1.5 L min(-1) (±20%). RIPLS produces valid measures of fB among controls but not OHS patients, and is not valid for quantifying respiratory volumes among either group.

Validity of arterialised-venous PCO2, pH and bicarbonate in obesity hypoventilation syndrome

This prospective study investigated the validity of arterialised-venous blood gases (AVBG) for estimating arterial carbon dioxide P CO2, pH and bicarbonate (HCO3(-)) in people with obesity hypoventilation syndrome (OHS). AVBGs were obtained from an upper limb vein, after heating the skin at 42-46°C. Arterial blood gas (ABG) and AVBG samples were taken simultaneously and compared using Bland Altman analysis. Between-group differences were assessed with independent t-tests or Mann-Whitney U tests. Forty-two viable paired samples were analysed, including 27 paired samples from 15 OHS participants, and 15 paired samples from 16 controls. AVBG-ABG agreement was not different between groups, or between dorsal hand, forearm and antecubital AVBG sampling sites, and was clinically acceptable for P Co2: mean difference (MD) 0.4 mmHg (0.9%), limits of agreement (LOA) -2.7-3.6 mmHg (± 6.6%); pH: MD -0.008 (-0.1%), LOA -0.023-0.008 (± 0.2%); and HCO3(-): MD -0.3 mmol L(-1) (-1.0%), LOA -1.8-1.2 mmol L(-1) (± 5.3%). AVBG provides valid measures of [Formula: see text] , pH, and HCO3(-) in OHS.

Effect of non-invasive ventilation on the measurement of ventilatory and metabolic variables.

The effect of non-invasive ventilation (NIV) on the accuracy of measurements of ventilation, oxygen consumption (V˙O2) and carbon dioxide production (V˙CO2) was examined using a simulator. Known gas volumes of oxygen and carbon dioxide were delivered to a metabolic system that measured tidal volume, respiratory rate, V˙O2 and V˙CO2, both with and without NIV. Bland-Altman analyses were used to compare between conditions. NIV at pressure support (PS) 20cm H2O compared to without NIV showed: VT, mean difference (MD) 0mL (limits of agreement (LOA) -21 to 21) mL; V˙O2 MD -413 (LOA -810 to 16) mL/min; and V˙CO2 MD 32 (LOA -32 to 97) mL/min. For V˙O2 measurements during NIV, a correction was applied to account for increased air density due to PS. After correction, V˙O2 measurement accuracy improved; MD -46 (LOA -108 to 17) mL/min. Tidal volume and metabolic variables can be measured with acceptable accuracy during NIV, providing V˙O2 is corrected for altered gas density.