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At least 19 recordsLinked to original sources

Perspectives on physiological monitoring: junctional-type potentials in the food ventricle.

1. Many toads monitored throughout survival with no support other than protection against drying, pass terminally through a remarkable evolution which is described here in the full details of a single experiment lasting some 40 hours. 2. The essential features of this particular sequence is block of the Luciani-Wenckebach type affecting SA, AV, and intraventricular conduction. SA block was apparently the major cause of periods of arrest and of cycles of heart beats. Periodically PR delay based on progressive AV block was observed but it was not an outstanding feature. 3. Progressive, rate-determined intraventricular block during the cycles of ventricular beats was the first new feature of these observations. 4. As intraventricular block progressed, an initial ventricular deflection separated itself from the rest of QRS. 5. This initial deflection diminished in amplitude throughout each cycle of ventricular beats, its rate of rise diminished, and the interval separating it from the rest of the ventricular complex increased until the whole initial deflection was revealed. 6. Thereafter, with a small decrease in amplitude of the initial deflection, the remainder of the ventricular electrogram failed to follow and the complex stood alone. 7. Its polarity indicated its origin at the base of the ventricle, the interval separating it from the origin of P indicated that it was downstream from the AV conduction mechanism. 8. This deflection, now a local ventricular potential (LVP) then progressively declined in amplitude and disappeared. 9. The possibility has been discussed that the potential represents (a) a true action potential localized by block or (b) a local, nonpropagated potential akin to junctional potentials like: (1) end-plate potentials, (2) generator potentials, (3) excitatory postsynaptic potentials (EPSPs), or (c) a pacemaker potential. The experiments that have revealed the phenomenon have not provided other than suggestive but inconclusive information about its nature. 10. The observations are new or certainly not well known and further study should shed light on the problem of intracardial impulse formation and conduction.

Animals

Chamber-based system for physiological monitoring of submerged exercising subjects.

A system has been designed which allows for measurement of cardiorespiratory parameters in the fully submerged subject performing graded exercise. It consists of a horizontal wet chamber; a waterproofed, electrically braked bicycle ergometer; and a low-resistance "bag-in-a-box" breathing apparatus. Chamber and breathing apparatus design allow for a great deal of flexibility in both positioning of the subject and instrumentation. The 200-liter "bag-in-a-box" configuration provides the subject with humidified gas through 2.5 in. i.d. tubing. A rolling seal spirometer provides the lung counter volume. Provision is made for breath-by-breath gas analysis with a mass spectrometer. Hydrostatic pressure on the diver's thorax relative to chamber pressure can be easily and reproducibly varied over a wide range of positive and negative static lung loads. This system has been used on over 100 man-dives to depths equivalent to 6.5 ATA with oxygen consumptions up to 4.0 liters/min.

Humans

Physiologic monitoring goals for the critically ill patient.

Definition of the appropriate therapeutic goals for physiologic monitoring of patients postoperatively was approached by analyzing more than 50,000 values of the 20 most commonly monitored variables in a series of 113 critically ill patients throughout their immediate postoperative course. In general, normal values were poor criteria for monitoring, since normal values were restored in an average of 75 per cent of the survivors and 76 per cent of the nonsurvivors for the five most frequently measured variables; that is, arterial pressure, heart rate, central venous pressure, wedge pressure and cardiac output. Moreover, an average of 56 per cent of the 20 most commonly monitored variables of nonsurvivors was restored to the normal range. Furthermore, 34 per cent of all the nonsurvivors' values were within the normal range; this was only 2.4 per cent less than the percentage of normal values for the survivors. The empirically determined median value of the survivors taken in the late stage during periods remote from therapy was found to be a better criterion for therapeutic goals for most variables, including blood flow, oxygen transport and most intravascular pressures. However, normal values were satisfactory for arterial pressure, peripheral resistance, pH, mixed venous oxygen tension and arterial carbon dioxide tension, largely because of the biphasic patterns of these variables.

Blood Chemical Analysis

The use of Doppler shift radar to monitor physiological and drug induced activity patterns in the rat.

Doppler shift radar was used to monitor circadian activity patterns in the rat and to study the behavioural effects of p-chloroamphetamine and d-amphetamine. Activity was classified in two ways:-(a) slow (non-locomotory) and high (locomotory) speed movements. (b) the number of starts of activity, within either the slow or high speed zones of activity during a pre-set time. p-Choloramphetamine (5 mg/kg) produced a biphasic activity response; an initial increase in continuous non-locomotory activity followed by a longer lasting increase in exploratory locomotion containing regular starts of activity. d-Amphetamine (2.5 mg/kg) produced an increase in both non-locomotory and locomotory movements but a marked reduction in starts of activity (i.e. continuous non-exploratory activity). The combination of information on the amount and pattern (starts) of activity allows a more detailed analysis of the effects of drugs on activity to be made than with existing automated methods.

Animals

Intraoperative physiologic monitoring and management during hepatic lobectomy using the liver isolation-perfusion technic.

The high operative mortality of major hepatic resection for tumor can be improved by a technic of resection using complete vascular isolation and hypothermic perfusion of the liver. Complete clamping of the portal vein, vena cava, and hepatic artery was necessary and well tolerated. Major physiologic, biochemical, and coagulation changes, however, can occur with this technic that requires close monitoring by the anesthesiologist. With astute observation and prompt corrective measures when indicated, these changes can be minimized to enable a safe and smooth resection to be carried out.

Acid-Base Equilibrium

Perspectives in physiological monitoring.

Clinical monitoring systems that have been developed in response to the need to acquire patient physiological data have only recently been accepted as standard equipment in the operating room, and burgeoned into the variety of sophisticated patient-monitoring equipment available today. This article traces the history of the recognition of the importance of physiological data in diagnosing and treating disease, the inclusion of the four vital signs on patient charts, and the first instrumental recording of these signs, all of which occurred before 1900. The earliest operating room monitoring system, which was not developed until the mid 1940s, is described.

Animals

Noninvasive ambulatory monitoring of physiologic data: recording systolic time intervals.

Adding physiologic data to ambulatory electrocardiographic monitoring data yields information with great potential for diagnostic and therapeutic use. The ear densitogram's stability, demonstrated during exercise and under laboratory conditions, indicates its applicability to ambulatory monitoring as a source of systolic time intervals. Circuitry has been developed to feed the output of an ear densitogram pickup into one channel of a two-channel Holter monitor. Baseline studies in different postures are used to establish pulse transmission time, which permits the ear densitogram pulse to be used as a delayed aortic pulse in measuring systolic time interval. Feasibility and field studies have shown that systolic time intervals can be precisely determined by this method.

Activities of Daily Living

Cardiac and respiratory monitoring of acute stroke patients.

This study evaluates physiologic monitoring as a tool for improved nursing observation of acute stroke patients. Forty-four patients admitted within 48 hours of onset of stroke were monitored using an automated arrhythmia detection system and impedance pneumography. Cardiac arrhythmias were observed in 25 of 44 patients. Three patients with episodes of atrial fibrillation were digitalized and converted to normal sinus rhythm. Respiratory patterns were intermittently abnormal in 39 of 44 patients. The presence of intermittent Cheyne-Strokes respirations or tachypnea was associated with an increased mortality rate. Cardiac monitoring appears to be a useful tool for prompt detection of potentially serious arrhythmias in stroke patients. Respiratory monitoring is useful for detection of abnormalities of respiratory rate and pattern; these abnormalities may serve as an early indicator of change in neurologic status.

Arrhythmias, Cardiac

Pulmonary artery pressure monitoring in persistent fetal circulation (PFC).

The use of the Swan-Ganz catheter to monitor pulmonary artery pressure in adults with cardiopulmonary failure has become commonplace. Our meager experience was with four neonates diagnosed as having persistent fetal circulation monitored by the use of this PA catheter. Tolazoline was infused directly into the pulmonary circulation via the catheter. Pulmonary artery pressure was temporarily reduced by tolazoline administration, with a marked increase in PaO2. More experience is required to define the role of the Swan-Ganz catheter in neonatal physiologic monitoring.

Blood Pressure