Journal of clinical monitoring
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Comparative Study
Evaluation of a continuous noninvasive blood pressure monitor in obstetric patients undergoing spinal anesthesia.
A noninvasive blood pressure monitor (Finapres) that continuously displays the arterial waveform using the Penaz methodology has recently been introduced into clinical practice. We compared this device with an automated oscillometric blood pressure monitor (Dinamap 1846SX) in 20 patients during spinal anesthesia for nonemergency cesarean section according to a procedure suggested by the Association for the Advancement of Medical Instrumentation. After administration of the spinal anesthetic, the Finapres monitor produced systolic, mean, and diastolic pressure measurements greater than those of the Dinamap monitor (6.6 +/- 12.5, 3.3 +/- 10.4, and 7.2 +/- 9.8 mm Hg, respectively). ⋯ The Finapres monitor occasionally stopped working and had to be restarted. In 1 patient (not included in this analysis), the Dinamap monitor was unable to determine the blood pressure due to patient shivering; this did not appear to interfere with the Finapres. We conclude that the Finapres monitor does not consistently provide blood pressure information equivalent to that of the Dinamap in obstetric patients undergoing spinal anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)
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Patients receiving intraspinal opiates should be monitored in the intensive care unit for at least 24 hours to prevent potentially lethal outcomes. These include respiratory depression caused by sequestration of the morphine in the cerebrospinal fluid and migration of epidural catheters in the subarachnoid or intravascular space. At this time, most hospitals are not equipped or staffed adequately to guarantee the safety of these patients outside the intensive care unit.
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Most patients receiving spinal narcotics can be monitored adequately by well-trained nurses on postoperative or postdelivery wards. Patients at high risk (e.g., those with preexisting lung disease or many elderly patients) do need monitoring in the intensive care unit. Also requiring special monitoring are patients for whom epidural narcotics alone will not cover their pain, such as young patients with multiple trauma. Patients without these restrictions, however, can be monitored successfully outside the intensive care unit, although the dose of epidural narcotic should be kept as low as possible.
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The administration of anesthesia may be viewed as a closed-loop control system consisting of three major components: the anesthesia system, the patient, and the system operator. A monitoring and alarm system during anesthesia should not be limited to only one of the three major components but must include monitoring of the patient, the performance of the anesthesia system, and the action of the system operator. ⋯ The authors describe the characteristics of a structured alarm system that maximizes the time available to correct a potential problem before injury begins, that clearly identifies the cause of the problem, and that prioritizes alarms according to the urgency of the required response. Alarms should be easy to temporarily silence, have built-in alarm default settings to prevent the inadvertant use of settings meant for a previous patient, and have a graphic display that enables the operator to detect problems or trends before an alarm sounds.
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Respiratory oxygen, carbon dioxide, and nitrous oxide concentrations were recorded in 20 patients breath-by-breath during general anesthesia and early recovery, using the Cardiocap multiparameter monitor. Several approved maneuvers were performed to demonstrate the usefulness of endtidal oxygen measurement. "Oxygrams" provided by the fast paramagnetic oxygen sensor confirmed the capnometric information in the diagnosis of hypoventilation, apnea, and disconnections. In one patient, the alarm for inspiratory oxygen concentration, set at 18%, appeared to prevent alveolar hypoxia and low arterial saturation from occurring when oxygen instead of nitrous oxide was turned off. ⋯ Changes in nitrous oxide concentration often complemented oxygen-related information obtained in our observations. In the recovery room, a decrease in end-tidal oxygen concentration preceded low pulse oximetry readings. Therefore, it is suggested that all three gases should be monitored continuously to prevent mishaps related to insufficient ventilation and inappropriate gas concentrations during anesthesia and immediate recovery.