Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Clinical TrialAccuracy of capnography with a 30 foot nasal cannula for monitoring respiratory rate and end-tidal CO2 in children.
We tested the accuracy of a low flow (50 cc/min) sidestream capnography system equipped with an experimental 30-foot nasal cannula to monitor ventilatory status in children. End-tidal CO2 and respiratory rate, both at room air and in the presence of supplemental oxygen, were recorded simultaneously from the experimental 30-foot nasal cannula and the standard, FDA approved, 10-foot nasal cannula. The 30-foot nasal cannula was as accurate as the 10-foot nasal cannula in measuring respiratory rate and end-tidal CO2 in children. When supplemental oxygen was delivered by face-mask, there was no dilutional effect on the respiratory rate or end-tidal CO2 recorded with either the 10-foot or 30-foot nasal cannulas in place.
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J Clin Monit Comput · Jan 2000
Randomized Controlled Trial Comparative Study Clinical TrialComparison of non-invasive blood pressure measurements on the arm and calf during cesarean delivery.
Shivering may occur in 75% of women undergoing spinal anesthesia for cesarean delivery and may render an automated noninvasive blood pressure (ANIBP) device incapable of determining blood pressurc (BP). When patients shiver under spinal anesthesia, the lower extremities do not exhibit the same involuntary muscle movements as do the upper extremities. This study was undertaken to determine if a correlation exists between ANIBP measurements in the arm and calf of women undergoing cesarean delivery under spinal anesthesia. ⋯ We conclude that there is a poor correlation between the BP measured by an ANIBP on the calf and one on the arm. In the parturient undergoing cesarean section, lower extremity BP as measured by an ANIBP does not correlate with the arm ANIBP and should not be used to assure fetal well being.
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Noninvasive ventilation refers to any form of ventilatory support applied without the use of an endotracheal tube. It offers the potential to provide primary treatment for acute respiratory failure while avoiding complications associated with mechanical ventilation with endotracheal intubation. Noninvasive ventilation has been most commonly studied in hypercapnic respiratory failure. ⋯ Patient selection is clearly the most important issue in considering noninvasive ventilation for acute respiratory failure. Unfortunately, patients who benefit from noninvasive ventilation represent only a minority of the total group with any one disease, and thus it is difficult to make broad conclusions concerning applicability of this treatment modality. Future studies are needed to focus on determining the specific patient populations who will benefit the most, evaluating the optimal ventilatory mode and mask for providing noninvasive ventilation, and clarifying its impact on clinical outcomes.
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J Clin Monit Comput · Jan 2000
ReviewAtelectasis formation during anesthesia: causes and measures to prevent it.
Pulmonary gas exchange is regularly impaired during general anaesthesia with mechanical ventilation. This results in decreased oxygenation of blood. A major cause is collapse of lung tissue (atelectasis), which can be demonstrated by computed tomography but not by conventional chest x-ray. ⋯ In summary, atelectasis is present in most humans during anaesthesia and is a major cause of impaired oxygenation. Avoiding high fractions of oxygen in inspired gas during induction and maintenance of anaesthesia may prevent formation of atelectasis. Finally, intermittent "vital capacity"-manoeuvres together with PEEP reduces the amount of atelectasis and pulmonary shunt.
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J Clin Monit Comput · Jan 2000
ReviewAssessment and monitoring of flow limitation and other parameters from flow/volume loops.
Flow/volume (F/V) spirometry is routinely used for assessing the type and severity of lung disease. Forced vital capacity (FVC) and timed vital capacity (FEV1) provide the best estimates of airflow obstruction in patients with asthma, chronic obstructive pulmonary disease (COPD) and emphysema. Computerized spirometers are now available for early home recognition of asthma exacerbation in high risk patients with severe persistent disease, and for recognition of either infection or rejection in lung transplant patients. ⋯ Finally, the mechanism of ventilatory constraint can be identified with the use of exercise tidal volume F/V loops referenced to maximum F/V loops and static lung volumes. Patients with severe COPD show inspiratory F/V loops approaching 95% of total lung capacity, and flow limitation over the entire expiratory F/V curve during light levels of exercise. Surprisingly, patients with a history of congestive heart failure may lower lung volume towards residual volume during exercise, thereby reducing airway diameter and inducing expiratory flow limitation.