BACKGROUND

Expiratory flow limitation (EFL) is the primary pathophysiological hallmark of chronic obstructive pulmonary disease (COPD). However, the effect of lower-extremity endurance training alone on EFL in patients with COPD remains largely unknown.

OBJECTIVE

This study aims to determine the effects of endurance training on EFL and dynamic hyperinflation in patients with stable COPD.

METHODS

This was a prospective, single-blinded, non-randomised controlled 12-week study recruiting Chinese patients with stable COPD in an endurance training group (n = 15) or a control group (n = 13). Before and at the end of the study, we measured the EFL, pulmonary function, peak inspiratory flow (PIF) and maximum inspiratory pressure (MIP); moreover, the patients underwent a constant work rate exercise test in which Borg dyspnoea scale, tidal breathing flow volume curves and inspiratory capacity (IC) were determined every other minute.

RESULTS

Exercise training significantly improved the exercise endurance time (7.00 ± 3.05 vs 18.13 ± 6.44 min, P < 0.001), MIP (69.49 ± 16.03 vs 80.18 ± 15.97 cmH2 O, P < 0.001) and PIF (3.96 ± 1.01 vs 4.51 ± 1.13 L/s, P = 0.014), but not EFL (3.33 ± 0.49 vs 3.40 ± 0.51, P = 0.334). Subjects on training had decreased breathing frequency (26.26 ± 7.13 vs 23.15 ± 5.34 breaths/min, P = 0.002), minute ventilation (30.28 ± 7.52 vs 26.85 ± 4.17 L, P = 0.013), tidal peak expiratory flow (1.53 ± 0.22 vs 1.32 ± 0.20 L/s, P = 0.006), mean expiratory flow (0.87 ± 0.19 vs 0.68 ± 0.15 L/s, P = 0.011) and Borg dyspnoea score (7.20 ± 1.15 vs 3.93 ± 1.39, P < 0.001), as well as increased IC (1.50 ± 0.34 vs 1.67 ± 0.45 L, P = 0.002), expiratory time (1.47 ± 0.62 vs 1.72 ± 0.62 s, P = 0.004) and inspiratory flow reserve (2.05 ± 1.10 vs 2.95 ± 1.19 L/s, P = 0.002) at isotime. These changes were not observed in the control group.

CONCLUSIONS

Endurance training may benefit stable COPD patients in improving exercise endurance, inspiratory muscle strength, ventilatory requirements, exercise-induced hyperinflation and exertional dyspnoea.

Piroxicam H(2)PIR (H(2)PIR, 4-hydroxy-2-methyl-N-pyridin-2-yl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide), [Cu(HPIR)(2)(H(2)O)(2)] previously prepared and tested from this laboratory and at National Institute of Health, National Cancer Institute, Developmental Therapeutic Program, NIH-NCI-DTP, USA [R. Cini, G. Tamasi, S. Defazio, M.B. Hursthouse, J. Inorg. Biochem. 101 (2007) 1140-1152, and references cited therein], [Cu(HMEL)(2)(DMF)] (H(2)MEL, 4-hydroxy-2-methyl-N-(5-methyl-1,3-thiazol-2-yl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide; DMF, N,N-dimethylformamide), [Cu(HISO)(2)] (H(2)ISO, 4-hydroxy-2-methyl-N-(5-methylisoxazol-3-yl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide), and [Cu(HTEN)(2)(H(2)O)(2)] (H(2)TEN, 4-hydroxy-2-methyl-N-pyridin-2-yl-2H-thieno[2,3-e][1,2]thiazine-3-carboxamide 1,1-dioxide), were loaded on CMH2 hydrogel (co-1:10-poly(N-methacryloyl-L-histidine-co-N-isopropylacrylamide) cross-linked with N,N'-ethylene-bis-acrylamide (EBA) 2%) and the kinetics of release of Cu-HPIR species in several media were studied. The release of Cu(HPIR)(2) in DMSO from CMH2 hydrogel after swelling and loading from DMSO followed a diffusion controlled process. The release of Cu(HPIR)/Cu(HPIR)(2) from dried CMH2 hydrogel after swelling and loading from THF solution, then soaking into water/DMSO 95:5 v/v (pH 5.6) followed a relaxation controlled and diffusion controlled mechanism. The amount of Cu(HPIR)(2) released in the medium reached 0.03 microg Cu/mg gel/mL, i.e. ca 0.8 microM within 48 h that compares well with the IC(50) values reported for metal based drugs like carboplatin (diammino(1,1-cyclobutandicarboxylato)platinum(II)) against certain human tumor cell lines. The release studies performed by monitoring both the absorbance values at 362 nm (sensitive to metal-bound HPIR(-)) and the content of Cu via AAS, showed an excellent agreement with the Cu(HPIR)(2) or Cu(HPIR)(2) stoichiometry, depending on the delivery medium. Corresponding studies were performed for other Cu(oxicam-H)(2) species in different delivery media.

We thought that the rate of postoperative pulmonary complications might be higher after pressure-controlled ventilation than after volume-controlled ventilation. We analysed peri-operative data recorded for 109,360 adults, whose lungs were mechanically ventilated during surgery at three hospitals in Massachusetts, USA. We used multivariable regression and propensity score matching. Postoperative pulmonary complications were more common after pressure-controlled ventilation, odds ratio (95%CI) 1.29 (1.21-1.37), p < 0.001. Tidal volumes and driving pressures were more varied with pressure-controlled ventilation compared with volume-controlled ventilation: mean (SD) variance from the median 1.61 (1.36) ml.kg-1 vs. 1.23 (1.11) ml.kg-1 , p < 0.001; and 3.91 (3.47) cmH2 O vs. 3.40 (2.69) cmH2 O, p < 0.001. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at positive end-expiratory pressures < 5 cmH2 O was 1.40 (1.26-1.55) and 1.20 (1.11-1.31) when ≥ 5 cmH2 O, both p < 0.001, a relative risk ratio of 1.17 (1.03-1.33), p = 0.023. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at driving pressures of < 19 cmH2 O was 1.37 (1.27-1.48), p < 0.001, and 1.16 (1.04-1.30) when ≥ 19 cmH2 O, p = 0.011, a relative risk ratio of 1.18 (1.07-1.30), p = 0.016. Our data support volume-controlled ventilation during surgery, particularly for patients more likely to suffer postoperative pulmonary complications.

BACKGROUND

Stress and strain are parameters to describe respiratory mechanics during mechanical ventilation. Calculations of stress require invasive and difficult to perform esophageal pressure measurements. The hypothesis of the present study was: Can lung stress be reliably calculated based on non-invasive lung volume measurements, during a decremental Positive end-expiratory pressure (PEEP) trial in mechanically ventilated patients with different diseases?

METHODS

Data of 26 pressure-controlled ventilated patients admitted to the ICU with different lung conditions were retrospectively analyzed: 11 coronary artery bypass graft (CABG), 9 neurology, and 6 lung disorders. During a decremental PEEP trial (from 15 to 0 cmH2 O in three steps) end-expiratory lung volume (EELV) measurements were performed at each PEEP step, without interruption of mechanical ventilation. Strain, specific elastance, and stress were calculated for each PEEP level. Elastance was calculated as delta PEEP divided by delta PEEP volume, whereas specific elastance is elastance times the FRC. Stress was calculated as specific elastance times the strain. Global strain was divided into dynamic (tidal volume) and static (PEEP) strain.

RESULTS

Strain calculations based on FRC showed mainly changes in static component, whereas calculations based on EELV showed changes in both the static and dynamic component of strain. Stress calculated from EELV measurements was 24.0 ± 2.7 and 13.1 ± 3.8 cmH2 O in the lung disorder group at 15 and 5 cmH2 O PEEP. For the normal lungs, the stress values were 19.2 ± 3.2 and 10.9 ± 3.3 cmH2 O, respectively. These values are comparable to earlier publications. Specific elastance calculations were comparable in patients with neurologic and lung disorders, and lower in the CABG group due to recruitment in this latter group.

CONCLUSIONS

Stress and strain can reliably be calculated at the bedside based on non-invasive EELV measurements during a decremental PEEP trial in patients with different diseases.

Haemodynamic changes were studied in 51 patients undergoing orthopaedic surgery of the lower extremity, including exsanguination and thigh tourniquet for longer than 60 min. The patients were randomly divided into three anaesthesia groups: general anaesthesia (including enflurane), epidural anaesthesia (20 ml 0.5% bupivacaine) and spinal anaesthesia (3 ml 0.5% bupivacaine). During the study, five epidural and one spinal patient excluded from haemodynamic comparison required general anaesthesia because of pain from the surgery or ischaemia. In the general anaesthesia group, there was a rise in either systolic or diastolic arterial pressure of over 30% of the control value in 8/15 patients. In the spinal anaesthesia patients, there was a transient rise above 30% in only one patient out of 15 and no rise in the 15 epidural group patients. On the other hand, 11/15 of the epidural patients needed additional analgesics and/or sedation for pain or restlessness. The mean rise in the haemodynamic parameters including CVP was small on inflation of the tourniquet cuff; on deflation there was a mean decrease in CVP of 1-3 cmH2 (0.1-0.3 kPa), the maximum decrease being 8 cmH2O (0.8 kPa). The mean decrease in systolic arterial blood pressure ranged from 2 to 14 mmHg (0.27 to 1.87 kPa) when the cuff was deflated.

BACKGROUND

Coal mine dust exposure can cause both pneumoconiosis and chronic airflow limitation. The contributions of various pathophysiologic mechanisms to dust-related lung function decrements remain unclear.

METHODS

Clinical and physiological findings were assessed for 15 underground coal miners who had demonstrated accelerated FEV1 losses (decliners) over 6-18 years. Decliners' findings were evaluated in comparison to a group of 11 miners who had shown relatively stable lung function (referents) during the same period.

RESULTS

At follow-up examination, the decliners showed significantly greater mean airway resistance (10.47 vs. 6.78 cmH2 O/L/s; P = 0.05) and more air trapping (RV/TLC = 37.5 vs. 29.1%; P < 0.01) compared to the referents. Decliners also demonstrated more evidence of small airways dysfunction and tended to have more bronchospasm than the referent group. Total lung capacity, lung compliance, diffusing capacity, and chest radiography did not differ significantly between the two groups. After cessation of mine dust exposures, the decliners' mean rate of FEV1 loss normalized.

CONCLUSIONS

In a series of working coal miners, accelerated lung function declines were associated with air trapping and evidence of small airways dysfunction. A preventive benefit from controlling dust exposures was suggested.

OBJECTIVE

This study aims to determine if there is a difference in the pharyngeal pressure, measured as a surrogate for continuous positive distending airway pressure, delivered to premature infants between two commonly used heated, humidified high-flow nasal cannulae (HHHFNC) devices: Fisher & Paykel Healthcare HHHFNC and Vapotherm 2000i.

METHODS

Pharyngeal pressure measurements were taken from stable premature infants receiving HHHFNC for respiratory support. Flow rates of 2-8 L/min were studied.

RESULTS

Nine infants had pharyngeal pressure measurements recorded with both HHHFNC devices at flow rates of 2-8 L/min. There was no difference in pharyngeal pressures recorded between devices at flow rates of 2-6 L/min; measured pressure was linearly associated with flow (R(2) = 0.9). At flow rates of 7 L/min, Vapotherm delivered a mean (standard deviation) pharyngeal pressure of 4.7 (2.2) cmH2 O compared with 4.23 (2.2) cmH2 O by the Fisher & Paykel device (P = 0.04). At a flow of 8 L/min, the mean pharyngeal pressure via Vapotherm was 4.9 (2.2) cmH2 O compared with 4.1 (2.3) cmH2 O with the Fisher & Paykel device (P = 0.05).

CONCLUSIONS

Both HHHFNC delivered similar pharyngeal pressures at flow rates of 2-6 L/min. The pressure limiter valve of the Fisher & Paykel device attenuated the pharyngeal pressures at flows of 7 and 8 L/min. Vapotherm trended towards higher delivered pharyngeal pressure at flow rates 7 and 8 L/min, but the clinical significance of the difference remains unclear.

We conducted a randomised trial comparing the self-pressurised air-Q™ intubating laryngeal airway (air-Q SP) with the LMA-Unique in 60 children undergoing surgery. Outcomes measured were airway leak pressure, ease and time for insertion, fibreoptic examination, incidence of gastric insufflation and complications. Median (IQR [range]) time to successful device placement was faster with the air-Q SP (12 (10-15 [5-18])) s than with the LMA-Unique (14 (12-17 [6-22]) s; p=0.05). There were no statistically significant differences between the air-Q SP and LMA-Unique in initial airway leak pressures (16 (14-18 [10-29]) compared with 18 (15-20 [10-30]) cmH2 O, p=0.12), an airway leak pressures at 10 min (19 (16-22 [12-30]) compared with 20 (16-22 [10-30]) cmH2 O, p=0.81); fibreoptic position, incidence of gastric insufflation, or complications. Both devices provided effective ventilation without the need for airway manipulation. The air-Q SP is an alternative to the LMA-Unique should the clinician prefer a device not requiring cuff monitoring during anaesthesia.

BACKGROUND

Spontaneous cerebrospinal fluid (CSF) leaks/encephaloceles are proven to be associated with intracranial hypertension by objective measurements of CSF pressure during or following endoscopic repair. A common area of involvement is a pneumatized lateral recess of the sphenoid (LRS) sinus, where prolonged intracranial pressures lead to arachnoid pits and subsequent development of skull-base defects. Even though the LRS is never present at birth, a "congenital" cause of these leaks due to a persistent Sternberg's (lateral craniopharyngeal) canal continues to be erroneously perpetuated in the literature. The objective of this study was to eliminate the myths defining these leaks as congenital in nature.

METHODS

Evaluation of LRS CSF leaks present within a multiinstitutional case series was performed. Data regarding demographics, body mass index (BMI), radiologic evaluation of intracranial hypertension, and direct intracranial pressure measurements (when available) were collected.

RESULTS

Data evaluation identified 77 LRS CSF leaks in 59 patients (mean age 52 years). Obesity was present in 83% of individuals (mean BMI 36) and 81% were females. Radiologic evidence of intracranial hypertension (eg, empty sella, dilated optic nerve sheaths, and scalloped/attenuated bone) was present on 96% of preoperative computed tomography (CT) and/or magnetic resonance imaging (MRI) scans. Opening or postsurgical lumbar drain or ventriculostomy pressure measurements were elevated in 95% of patients (mean 27.7; range, 9-50 cmH2 O).

CONCLUSIONS

This study provides objective evidence that LRS CSF leaks are secondary to erosions from intracranial hypertension and refutes the myth regarding a congenital origin from Sternberg's canal.

BACKGROUND

Shoulder tip and abdominal pain following laparoscopic procedures are well recognized causes of postoperative morbidity. In this double-blind randomized clinical trial attempts were made to reduce postoperative pain in patients undergoing laparoscopic surgery by implementing a simple intraoperative technique.

METHODS

Patients undergoing elective laparoscopic cholecystectomy or laparoscopic transabdominal preperitoneal inguinal hernia repair were randomized to receive either the current standard treatment (control group) or an intervention to remove residual carbon dioxide. In the intervention group, the pneumoperitoneum was removed at the end of the operation by placing the patient in the Trendelenburg position and utilizing a pulmonary recruitment manoeuvre consisting of two manual inflations to a maximum pressure of 60 cmH2 O. In the control group, residual pneumoperitoneum was evacuated at the end of the procedure by passive decompression via the open operative ports.

RESULTS

Seventy-six randomly assigned patients, 37 in the intervention group and 39 in the control group, were recruited. Overall postoperative pain scores were significantly lower in the intervention group (P = 0·001). Median (interquartile range) pain scores were significantly lower in the intervention group compared with the control group at both 12 h (3·5 versus 5; P < 0·010) and 24 h (3 versus 4·5; P < 0·010).

CONCLUSIONS

Active evacuation of residual pneumoperitoneum following laparoscopic procedures, by means of two pulmonary recruitment manoeuvres in the Trendelenburg position, reduces postoperative pain significantly. This simple and safe technique can be implemented routinely after abdominal laparoscopy.

BACKGROUND

NCT01720433 (http://www.clinical trials.gov).

Atelectasis occurs in the majority of children undergoing general anaesthesia. Lung ultrasound has shown reliable sensitivity and specificity for diagnosing anaesthesia-induced atelectasis. We assessed the effects of a recruitment manoeuvre on atelectasis using lung ultrasound in infants undergoing general anaesthesia. Forty infants, randomly allocated to either a recruitment manoeuvre group or a control group, received volume-controlled ventilation with 5 cmH2 O positive end-expiratory pressure. Lung ultrasound examination was performed twice in each patient, the first a minute after starting mechanical ventilation of the lungs and the second at the end of surgery. Patients in the recruitment manoeuvre group received ultrasound-guided recruitment manoeuvres after each lung ultrasound examination. The incidence of significant anaesthesia-induced atelectasis at the second lung ultrasound examination was less in the recruitment manoeuvre group compared with the control group (25% vs. 80%; p = 0.001; odds ratio (OR) 0.083; 95% confidence interval (CI): 0.019-0.370). The median (IQR [range]) lung ultrasound scores for consolidation and B-lines on the second examination were lower in the recruitment manoeuvre group compared with the control group; 6.0 (3.0-9.3 [0.0-14.0]) vs. 13.5 (11.0-16.5 [8.0-23.0]); p < 0.001 and 6.5 (3.0-12.0 [0.0-28.0]) vs. 15.0 (10.8-20.5 [7.0-28.0]); p < 0.001, respectively. The lung ultrasound scores for consolidation on the first and second examinations showed a negative correlation with age (r = -0.340, p = 0.008; r = -0.380, p = 0.003). We conclude that ultrasound-guided recruitment manoeuvres with positive end-expiratory pressure proved useful in reducing the incidence of anaesthesia-induced atelectasis in infants, although 5 cmH2 O positive end-expiratory pressure alone was not sufficient to eliminate it. In addition, the younger the patient, the more susceptible they were to atelectasis.

OBJECTIVE

To investigate the efficacy and urodynamic effects of baclofen in women with functional bladder outlet obstruction.

METHODS

Between January 2011 and December 2012, women who underwent baclofen treatment for functional bladder outlet obstruction, defined as <15 mL/s maximum flow rate and >20 cmH2 O detrusor pressure at maximum flow rate, but without significant anatomic causes, were retrospectively reviewed. Urodynamic variables at baseline and after 12 weeks of treatment were compared.

RESULTS

Twenty women with functional bladder outlet obstruction underwent 12 weeks of baclofen treatment (oral baclofen 5 mg, three times daily). All patients reported improvement in voiding dysfunction symptoms after treatment, and no significant adverse effects were found on review of medical records. All patients underwent urodynamic studies after 12 weeks' treatment. Voided volume, voiding efficiency and maximum flow rate at voiding cystometry were significantly improved (mean, 273 vs. 368 mL, P = 0.002; 62.8% vs. 73.6%, P <0.001, and 10.3 vs. 11.6 mL/s, P = 0.046; respectively). Moreover, baclofen did not affect continence function, as indicated by non-significant changes in the parameters of urethral pressure profiles.

CONCLUSIONS

Oral baclofen can improve symptoms of voiding dysfunction, voided volume, voiding efficiency and maximum flow rate in women with functional bladder outlet obstruction. None of the patients experienced intolerable side-effects. Thus, oral baclofen may be used as an initial treatment for women with symptoms of voiding dysfunction.

The aim of this study was to investigate the feasibility of using external urethral sphincter electromyogram (EMG) (EUSEMG) to detect the onset of detrusor contractions in patients with both neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia (DSD). Detrusor pressure (Pdet) and EUSEMG was recorded in 23 neurogenic patients during slow artificial bladder filling. The time delay between the onset of a detrusor contraction and the onset of EUSEMG activity was calculated together with the detrusor pressure increase related to this delay. Of 23 patients enrolled, 12 patients showed both NDO and DSD. Of these 12 patients, 10 had a strong correlation between detrusor pressure and EUSEMG. One patient in this group was excluded due to a storage pressure above 30 cm H2O. Two detection methods were applied on the remaining 9 patients. Method 1 was a root mean square (RMS)-integrator with simple thresholding. This approach had a good sensitivity but also a poor specificity (many false-positive detections). Detection method 2 included a kurtosis-based scaling function, which was multiplied to a similar RMS-integrator as used in method 1. Onset detection occurred before Pdet exceeded 18 cm H2O with both methods. However, method 1 resulted in 14.1 +/- 12.8 false-positive detections during one bladder filling. Pdet at onset detection was on average 1.0 +/- 1.1 cmH2 0 higher with detection method 2 but the number of false-positives was reduced by 95.8%. This paper demonstrates the feasibility of using EUSEMG to estimate the onset of a detrusor contraction in selected patients.

It is not well known what is the main mechanism causing lung heterogeneity in healthy lungs under mechanical ventilation. We aimed to investigate the mechanisms causing heterogeneity of regional ventilation and parenchymal densities in healthy lungs under anesthesia and mechanical ventilation.

In a small animal model, synchrotron imaging was used to measure lung aeration and regional-specific ventilation (sV̇). Heterogeneity of ventilation was calculated as the coefficient of variation in sV̇ (CVsV̇ ). The coefficient of variation in lung densities (CVD ) was calculated for all lung tissue, and within hyperinflated, normally and poorly aerated areas. Three conditions were studied: zero end-expiratory pressure (ZEEP) and FI O2 0.21; ZEEP and FI O2 1.0; PEEP 12 cmH2 O and FI O2 1.0 (Open Lung-PEEP = OLP).

The mean tissue density at OLP was lower than ZEEP-1.0 and ZEEP-0.21. There were larger subregions with low sV̇ and poor aeration at ZEEP-0.21 than at OLP: 12.9 ± 9.0 vs. 0.6 ± 0.4% in the non-dependent level, and 17.5 ± 8.2 vs. 0.4 ± 0.1% in the dependent one (P = 0.041). The CVsV̇ of the total imaged lung at PEEP 12 cmH2 O was significantly lower than on ZEEP, regardless of FI O2 , indicating more heterogeneity of ventilation during ZEEP (0.23 ± 0.03 vs. 0.54 ± 0.37, P = 0.049). CVD changed over the different mechanical ventilation settings (P = 0.011); predominantly, CVD increased during ZEEP. The spatial distribution of the CVD calculated for the poorly aerated density category changed with the mechanical ventilation settings, increasing in the dependent level during ZEEP.

ZEEP together with low FI O2 promoted heterogeneity of ventilation and lung tissue densities, fostering a greater amount of airway closure and ventilation inhomogeneities in poorly aerated regions.

OBJECTIVE

To investigate the outcome and complications of sacral deafferentation (SDAF) and sacral anterior root stimulation (SARS) in patients with neurogenic lower urinary tract dysfunction (NLUTD) resulting from complete spinal cord injury (SCI).

METHODS

Retrospective chart analysis of 137 patients who underwent SDAF/SARS at a single institution. Patients were categorized as being at risk of renal damage when the maximum detrusor pressure was >40 cmH2 O or detrusor compliance was <20 ml/cmH2 O.

RESULTS

After a mean follow-up time of 14.8 ± 5.3 years, SDAF/SARS treatment significantly (P < 0.001) reduced the number of patients suffering from elevated detrusor pressure from 65 to 2, and from low detrusor compliance from 62 to 13, respectively. Mean bladder capacity significantly (P < 0.001) improved from 272.4 ± 143.0 to 475.0 ± 82.7 ml. The mean number of symptomatic UTI also decreased significantly (P < 0.001) from 6.2 ± 4.5 to 2.5 ± 2.6 per year. The number of patients suffering from incontinence had significantly (P < 0.001) decreased from 70 to 44. At the last follow-up visit, 107 (78.1%) patients were still using the stimulator. A total of 84 complications requiring surgical revision were observed. Defects of the stimulator cables or the receiver plate were the most common events (n = 38). The retrospective design pertains to the limitations of the study.

CONCLUSIONS

Sacral deafferentation and SARS are an effective treatment option for refractory NLUTD in patients with complete SCI, despite a substantial long-term complication rate.

OBJECTIVE

Non-invasive techniques for measuring lung mechanics in infants are needed for a better understanding of lung growth and function, and to study the effects of prenatal factors on subsequent lung growth in healthy infants. The forced oscillation technique requires minimal cooperation from the individual but has rarely been used in infants. The study aims to assess the use of the forced oscillation technique to measure the influence of antenatal exposures on respiratory mechanics in unsedated infants enrolled in a birth cohort study in Cape Town, South Africa.

METHODS

Healthy term infants were studied at 6-10 weeks of age using the forced oscillation technique. Respiratory impedance was measured in the frequency range 8-48 Hz via a face mask during natural sleep. Respiratory system resistance, compliance and inertance were calculated from the impedance spectra.

RESULTS

Of 177 infants tested, successful measurements were obtained in 164 (93%). Median (25-75%) values for resistance, compliance and inertance were 50.2 (39.5-60.6) cmH2 O.s.L(-1), 0.78 (0.61-0.99) mL.cmH2 O(-1) and 0.062 (0.050-0.086) cmH2 O.s(2) .L(-1), respectively. As a group, male infants had 16% higher resistance (P = 0.006) and 18% lower compliance (P = 0.02) than females. Infants whose mothers smoked during pregnancy had a 19% lower compliance than infants not exposed to tobacco smoke during pregnancy (P = 0.005). Neither maternal HIV infection nor ethnicity had a significant effect on respiratory mechanics.

CONCLUSIONS

The forced oscillation technique is sensitive enough to demonstrate the effects of tobacco smoke exposure and sex in respiratory mechanics in healthy infants. This technique will facilitate assessing perinatal influences of lung function in infancy.

OBJECTIVE

Nasal high-frequency oscillatory ventilation (nHFOV) is a novel mode of non-invasive ventilation used in neonates. However, upper airway obstructions due to viscous secretions have been described as specific adverse effects. We hypothesized that high-frequency oscillations reduce air humidity in the oropharynx, resulting in upper airway desiccation. Therefore, we aimed to investigate the effects of nHFOV ventilatory settings on oropharyngeal gas conditions.

METHODS

NHFOV or nasal continuous positive airway pressure (nCPAP) was applied, along with heated humidification, to a previously established neonatal bench model that simulates oropharyngeal gas conditions during spontaneous breathing through an open mouth. A digital thermo-hygro sensor measured oropharyngeal temperature (T) and humidity at various nHFOV frequencies (7, 10, 13 Hz), amplitudes (10, 20, 30 cmH2 O), and inspiratory-to-expiratory (I:E) ratios (25:75, 33:66, 50:50), and also during nCPAP.

RESULTS

Relative humidity was always >99%, but nHFOV resulted in lower mean T and absolute humidity (AH) in comparison to nCPAP (P < 0.001). Specifically, decreasing the nHFOV frequency and increasing nHFOV amplitude caused a decline in T and AH (P < 0.001). Mean T and AH were highest during nCPAP (T 34.8 ± 0.6°C, AH 39.3 ± 1.3 g · m-3 ) and lowest during nHFOV at a frequency of 7 Hz and an amplitude of 30 cmH2 O (T 32.4 ± 0.3°C, AH 34.7 ± 0.5 g · m-3 ). Increasing the I:E ratio also reduced T and AH (P = 0.03).

CONCLUSIONS

Intensified nHFOV settings with low frequencies, high amplitudes, and high I:E ratios may place infants at an increased risk of upper airway desiccation. Future studies should investigate strategies to optimize heated humidification during nHFOV.

OBJECTIVE

To report our early results of augmentation enterocystoplasty (AE) for severe bladder pain associated with chronic ketamine cystitis (KC).

METHODS

We performed AE for 14 patients with refractory KC-related bladder pain, which is based on the criteria including severe bladder pain, urgency and frequency and/or upper urinary tract damage such as bilateral hydronephrosis, and contracted bladder. Every patient had been treated conservatively with medication or cystoscopic hydrodistention for at least 1 year before they had received surgical intervention. Video-urodynamic studies were obtained before AE and 3-6 months after surgery. Outcome measurements included visual analogue score (VAS) for pain, cystometric bladder capacity (CBC), maximum urinary flow rate (Qmax), post-void residual, and maximal detrusor pressure (Pdet). The patients' general satisfaction with regard to treatment outcome was also assessed by the Patient Perception of Bladder Condition (PPBC).

RESULTS

A total of 4 men and 10 women underwent this procedure as indicated. The mean age was 26.7 (ranged 20-38) years old and the duration of ketamine abuse was 3.82 years (ranged 2-7). Contracted bladder was noted in all patients, hydronephrosis in nine and vesicoureteral reflux (VUR) in eight. At 3-6 months after AE, VAS was remarkably improved from baseline to the end-point (8.29 ± 1.54 vs. 2.14 ± 1.51, P < 0.0001), CBC increased from 50.9 ± 15.7 to 309.2 ± 58.0 ml (P < 0.0001), Qmax increased from 6.94 ± 3.60 to 15.2 ± 5.51 ml/sec (P < 0.0001) and Pdet reduced from 29.7 ± 16.0 to 17.9 ± 8.2 cmH2 O (P = 0.008). All patients reported marked improvement in PPBC from 6.0 to 1.4 ± 0.89 (P < 0.0001). All hydronephrosis disappeared and VUR was resolved in five patients after AE with ureteral reimplantation.

CONCLUSIONS

This pilot study demonstrated that AE is effective in relieving refractory ketamine-related bladder pain and lower urinary tract symptoms.

OBJECTIVE

To explore the effects of different types of hysterectomy on lower extremity venous pressure.

METHODS

Ninety-nine patients with benign uterine diseases who were indicated for hysterectomy were included in the present prospective study. Patients were divided into three groups according to their preferences: (i) total laparoscopic hysterectomy (TLH) group (n = 36); (ii) transvaginal hysterectomy (TVH) group (n = 32); and (iii) transabdominal hysterectomy (TAH) group (n = 31). Lower extremity venous pressure was monitored using a pressure sensor during the surgery.

RESULTS

Compared with the supine position (TAH group, lower extremity venous pressure of intraoperative 16.50 cmH2 O), lower extremity venous pressure of the improved lithotomy position (TLH group, lower extremity venous pressure of intraoperative 53.27 cmH2 O) and conventional lithotomy position (TVH group, lower extremity venous pressure of intraoperative 42.09 cmH2 O) were significantly increased (P < 0.01).Venous pressure was reduced when patients lowered their heads by 15° or 5° in modified or conventional lithotomy positions, respectively (P < 0.01). Venous pressure was increased significantly after the establishment of pneumoperitoneum in the TLH group (P < 0.01).

CONCLUSIONS

Modified lithotomy position (TLH group) and conventional lithotomy position (TVH group) and CO2 pneumoperitoneum may result in increased lower extremity venous pressure during hysterectomy. Furthermore, elevated venous pressure can be altered by changing the intraoperative position. Specifically, intraoperative positioning of the lower extremities represents a modifiable risk factor for deep venous thrombosis.

BACKGROUND

Transpulmonary pressure is a key factor for protective ventilation. This requires measurements of oesophageal pressure that is rarely used clinically. A simple method may be found, if it could be shown that tidal and positive end-expiratory pressure (PEEP) inflation of the lungs with the same volume increases transpulmonary pressure equally. The aim of the present study was to compare tidal and PEEP inflation of the respiratory system.

METHODS

A total of 12 patients with acute respiratory failure were subjected to PEEP trials of 0-4-8-12-16 cmH2O. Changes in end-expiratory lung volume (ΔEELV) following a PEEP step were determined from cumulative differences in inspiratory-expiratory tidal volumes. Oesophageal pressure was measured with a balloon catheter.

RESULTS

Following a PEEP increase from 0 to 16 cmH2O end-expiratory oesophageal pressure did not increase (0.5 ± 4.0 cmH2O). Average increase in EELV following a PEEP step of 4 cmH2O was 230 ± 132 ml. The increase in EELV was related to the change in PEEP divided by lung elastance (El) derived from oesophageal pressure as ΔPEEP/El. There was a good correlation between transpulmonary pressure by oesophageal pressure and transpulmonary pressure based on El determined as ΔPEEP/ΔEELV, r(2) = 0.80, y = 0.96x, mean bias -0.4 ± 3.0 cmH2 O with limits of agreement from 5.4 to -6.2 cmH2O (2 standard deviations).

CONCLUSIONS

PEEP inflation of the respiratory system is extremely slow, and allows the chest wall complex, especially the abdomen, to yield and adapt to intrusion of the diaphragm. As a consequence a change in transpulmonary pressure is equal to the change in PEEP and transpulmonary pressure can be determined without oesophageal pressure measurements.

BACKGROUND

Venous admixture from atelectasis and airway closure impedes oxygenation during general anaesthesia. We tested the hypothesis that continuous positive airway pressure (CPAP) during pre-oxygenation and reduced fraction of inspiratory oxygen (FIO2 ) during emergence from anaesthesia can improve oxygenation in patients with obesity undergoing laparoscopic surgery.

METHODS

In the intervention group (n = 20, median BMI 41.9), a CPAP of 10 cmH2 O was used during pre-oxygenation and induction of anaesthesia, but no CPAP was used in the control group (n = 20, median BMI 38.1). During anaesthesia, all patients were ventilated in volume-controlled mode with an FIO2 of 0.4 and a positive end-expiratory pressure (PEEP) of 10 cmH2 O. During emergence, before extubation, the control group was given an FIO2 of 1.0 and the intervention group was divided into two subgroups, which were given an FIO2 of 1.0 or 0.31. Oxygenation was assessed perioperatively by the estimated venous admixture (EVA).

RESULTS

The median EVA before pre-oxygenation was about 8% in both groups. During anaesthesia after intubation, the median EVA was 8.2% in the intervention vs. 13.2% in the control group (P = 0.048). After CO2 pneumoperitoneum, the median EVA was 8.4% in the intervention vs. 9.9% in the control group (P>> 0.05). One hour post-operatively, oxygenation had deteriorated in patients given an FIO2 of 1.0 during emergence but not in patients given an FIO2 of 0.31.

CONCLUSIONS

A CPAP of 10 cmH2 O during pre-oxygenation and induction, followed by PEEP after intubation, seemed to preserve oxygenation during anaesthesia. Post-operative oxygenation depended on the FIO2 used during emergence.

OBJECTIVE

To determine the effectiveness of mirabegron in patients with neurogenic lower urinary tract dysfunction.

METHODS

Randomized, double-blind, placebo-controlled study. Canadian patients with spinal cord injury (SCI) or multiple sclerosis (MS) with urinary symptoms and incontinence were recruited. Patients were randomized to mirabegron 25 mg (or an identical placebo) for 2 weeks at which point a dose escalation to mirabegron 50 mg (or an identical placebo) was maintained for 8 weeks. Urodynamics were performed before and after treatment. The primary outcome measure was maximum cystometric capacity (MCC). Intention to treat analysis and ANCOVA models (with adjustment for baseline values) were used and marginal means (MM) are reported; P-value <0.05 was considered significant.

RESULTS

Sixteen (9 SCI and 7 MS) patients were randomized to mirabegron and 16 (10 SCI and 6 MS) to placebo. At study completion, there was no significant difference in MCC between mirabegron and placebo (MM 305 vs 369 mL, P = 0.20). There was no significant difference in volume at first neurogenic detrusor overactivity (NDO, MM 167 vs 137 mL, P = 0.14) and peak pressure of NDO (MM 69 vs 82 cmH2 O, P = 0.25). There was no significant difference in pad weights or voiding diary parameters. There was a significantly lower symptom burden among those treated with mirabegron (total neurogenic bladder symptom score MM 29 vs 34, P = 0.047).

CONCLUSIONS

Among patients with SCI or MS, we demonstrated non-significant trends towards improvement in some urodynamic parameters with mirabegron 50 mg compared to placebo, and a significantly lower neurogenic bladder symptom burden.

BACKGROUND

Breathing exercises with positive expiratory pressure are often recommended to patients with advanced neurological deficits, but the potential benefit in multiple sclerosis (MS) patients with mild and moderate symptoms has not yet been investigated in randomized controlled trials.

OBJECTIVE

To study the effects of 2 months of home-based breathing exercises for patients with mild to moderate MS on respiratory muscle strength, lung function, and subjective breathing and health status outcomes.

METHODS

Forty-eight patients with MS according to the revised McDonald criteria were enrolled in a randomized controlled trial. Patients performing breathing exercises (n = 23) were compared with a control group (n = 25) performing no breathing exercises. The breathing exercises were performed with a positive expiratory pressure device (10-15 cmH2 O) and consisted of 30 slow deep breaths performed twice a day for 2 months. Respiratory muscle strength (maximal inspiratory and expiratory pressure at the mouth), spirometry, oxygenation, thoracic excursion, subjective perceptions of breathing and self-reported health status were evaluated before and after the intervention period.

RESULTS

Following the intervention, there was a significant difference between the breathing group and the control group regarding the relative change in lung function, favoring the breathing group (vital capacity: P < 0.043; forced vital capacity: P < 0.025). There were no other significant differences between the groups.

CONCLUSIONS

Breathing exercises may be beneficial in patients with mild to moderate stages of MS. However, the clinical significance needs to be clarified, and it remains to be seen whether a sustainable effect in delaying the development of respiratory dysfunction in MS can be obtained.

OBJECTIVE

To investigate urodynamic efficacy and safety of mirabegron add-on treatment with tamsulosin for Japanese male patients with overactive bladder (OAB).

METHODS

A prospective study was conducted in 26 consecutive male patients with OAB who had been taking tamsulosin. OAB was diagnosed by overactive bladder symptom score (OABSS). Before and 8 weeks after mirabegron add-on treatment with preceding tamsulosin, we assessed OABSS, International Prostate Symptom Score (IPSS), free uroflowmetry (UFM), filling cystometry and pressure-flow study (PFS).

RESULTS

Mean age and prostate volume of the study patients were 75 ± 7 years and 32 ± 19 mL, respectively. Mirabegron significantly improved OABSS (from 8.5 ± 2.3 to 4.7 ± 2.5, P < 0.001). On free UFM, mirabegron significantly increased voided volume (from 135 ± 47 to 182 ± 102 mL, P = 0.01), maximum (from 10.7 ± 3.7 to 13.5 ± 6.4 mL/sec, P < 0.01) and average flow rate (from 5.5 ± 1.9 to 7.1 ± 3.3 mL/sec, P < 0.01), while postvoid residual urine volume did not change significantly (from 47 ± 38 to 63 ± 61 mL, P = 0.23). Before mirabegron, 24 patients (92%) had detrusor overactivity (DO). After mirabegron add-on, maximum cystometric capacity significantly increased from 170 ± 98 to 212 ± 95 mL (P = 0.01) and DO disappeared in six patients (25%). In the other 18 patients with persistent DO, amplitude of involuntary contraction decreased and bladder volume at first involuntary contraction increased with statistical significance. On PFS, detrusor pressure at maximum flow rate (from 79 ± 31 to 68 ± 19 cmH2 O, P = 0.10) or bladder contractility index (from 126 ± 39 to 120 ± 27, P = 0.45) did not change significantly.

CONCLUSIONS

Mirabegron add-on treatment with tamsulosin has efficacy and safety because it improves storage symptom without impairment of bladder contractility during voiding in male patients with OAB.