Physical management of spasticity.

Physical management of people with spasticity is a complex task requiring the collaborative work of a multidisciplinary team. This article reviews some of the most commonly used treatment techniques and theories that lay the framework for the physical management of spasticity. Most crucial to the management of the person with spasticity is the skillful application of the techniques and theories discussed. Given the complexity in the standardized evaluation of children with spasticity, it is recommended that existing outcome measures or standardized scales be applied wherever possible as an adjunct tool to the clinician's assessment and interventions. One must recognize the benefits of such scales and their limitations. Therefore, it is recommended that further development of standardized assessments be supported by funding agencies to develop both quantitative and qualitative measurement tools that will address the particular needs of the person with spasticity. Review of the literature supports the many interventions that are listed; however, further research is recommended by the consensus group.

Reducing the risks of laryngoscopy in anaesthetised infants.

We have evaluated the use of oxygen insufflation during laryngoscopy with an Oxyscope laryngoscope blade compared to conventional laryngoscopy for maintenance of transcutaneous PO2 during intubation of anaesthetised, spontaneously breathing infants. Twenty healthy children aged between 1 and 24 months were anaesthetised with halothane in oxygen. Laryngoscopy and intubation were performed in a double-blind fashion using a Miller No. 1 Oxyscope blade either with or without oxygen insufflation. Transcutaneous oxygen tension, arterial pressure and heart rate were measured before and after laryngoscopy, and duration of laryngoscopy was recorded. Transcutaneous oxygen tension decreased by 7.1% (SD 6.1%) when oxygen insufflation was used, compared to 33.0% (SD 15.1%) without oxygen insufflation (p less than 0.0001). There were no significant differences in mean duration of laryngoscopy or patient age. We conclude that oxygen insufflation during laryngoscopy and intubation of spontaneously breathing, anaesthetised infants effectively minimises the decrease in transcutaneous oxygen tension from pre-laryngoscopy levels, and makes instrumentation of the airway safer.

Gas exchange in low-compression HFPPV is maintained at low distending pressures in the pig.

The fact that collateral ventilation normally occurs in the human lung has led to the suggestion that it might contribute to the successful clinical effects of low-compression high-frequency positive-pressure ventilation (HFPPV). As the pig has poor collateral ventilation, pulmonary vasoconstriction has to be part of the regulatory mechanisms matching ventilation-perfusion. A study was made on nine pigs anesthetized with ketamine hydrochloride intravenously to elucidate the maintenance of ventilation-perfusion balance during mechanical ventilation. Comparisons were made between the ventilatory patterns provided by a conventional ventilator (Servo-Ventilator 900C) and an improved prototype of a low-compression system for volume-controlled ventilation (system H). A ventilatory frequency of 20 breaths per min (bpm) with SV-900C (SV-20) and system H (H-20) and of 60 bpm with system H (H-60) was used. The experimental conditions were otherwise identical. Positive end-expiratory pressures (PEEP) were applied to maintain the same mean airway pressure with the three systems. The tidal volume required for normoventilation differed significantly between the three ventilatory patterns, but there were no differences in circulatory and oxygen-transport variables. By measurements of airway pressure and intrapleural liquid surface pressure, it was demonstrated that the distending pressure (at end-inspiration) was significantly lower with a low-compression system (H-20 versus SV-20), especially at a high ventilatory frequency (H-60 versus H-20). Consequently, although the mean airway pressure was set at the same level for the three different ventilatory modalities, the distending pressures required for the same alveolar ventilation and arterial oxygenation differed significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional organ blood flow during high-frequency positive-pressure ventilation (HFPPV) and intermittent positive-pressure ventilation (IPPV).

The effect of high-frequency ventilation (HFV) on cerebral blood flow (CBF) at normal and elevated intracranial pressure (ICP) was compared with flows measured under the same conditions during intermittent positive pressure ventilation (IPPV). Renal, lung (bronchial artery supply), and cardiac blood flows also were measured during HFV and compared with flows observed during IPPV. Measurements were made in canines with stable hemodynamic variables and arterial CO2 and O2 tensions in the normal range, CBF during HFV was comparable to the CBF during IPPV. Following an increase in ICP to a mean of 44 +/- 18 mmHg (SD), mean CBF decreased to 22.5 +/- 11 ml . 100 g-1 . min-1 (SD) during IPPV and 21.7 +/- 13.2 ml . 100 g-1 . min-1 (SD) during HFV. No statistical differences could be noted in regional or global flow as a function of ventilatory mode. Renal, lung (bronchial artery supply), and cardiac blood flows also showed no statistical variation between HFV and IPPV. Ventilator-synchronous fluctuations in ICP observed during IPPV were reduced during HFV at normal ICP and eliminated by HFV at elevated ICP.

Positioning the right atrial catheter: a model for reappraisal.

A flexible Silastic casting of the human right atrium was developed to correspond to some in vivo human right atrium hemodynamic characteristics including chamber pressures, pulsatility, fluid output, and flow velocity. Using an infusion pump, air was introduced (10 ml in 30 s) into the superior vena cava of the model and aspirated via a catheter from different positions within the model atrial chamber. The tests were carried out at atrial inclinations of 60 degrees, 80 degrees, and 90 degrees from the horizontal and compared the aspiration efficiency of a single-orificed 16-gauge catheter to a 16-gauge multiorified (5 aperatures) catheter. Optimal air aspiration occurred with the multiorificed catheter tip positioned within the area 2.0 cm below the junction of the superior vena cava (SVC) and the atrial chamber at an inclination of 80 degrees. As much as 80 per cent of the incoming air could be aspirated under these conditions. At its optimal position the single-orificed catheter gave a maximal yield of 45 to 50 per cent aspiration when the tip was positioned 3.0 cm above the SVC and atrial chamber junction. Aspiration of air from mid right atrium (4.5 cm below the SVC-atrial junction) was poor regardless of the type of catheter used or atrial inclination. These data suggest a need for reappraisal of catheter design and placement.