摘要:

The construction of a Frank-Starling myocardial function curve relating heart work to left ventricular preload is clinically utilized to assess therapeutic protocols in critically ill patients. The pulmonary capillary wedge pressure (PWP) is the index of left ventricular filling pressure most frequently utilized as representative of left ventricular preload.The authors assessed the relationship between left ventricular preload measured as the left ventricular end-diastolic volume (LVEDV), and the PWP, in acutely ill patients with sepsis and cardiac disease. Within each group, no relationship was found between the LVEDV and the PWP; however, when omitting the effect of PEEP, a modest correlation was noted (r= 0.302;p< 0.01). Of the left ventricular ejection fraction. LVEDV and PWP, the PWP accounted for less than 5% of the explained variance in the stroke volume index.The PWP is a poor predictor of left ventricular preload, probably because of abnormalities of left ventricular compliance in critically ill patients.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The influence of CPR on the blood-brain barrier (BBB) in dogs was studied by fluorescence microscopy using Evans blue as a BBB tracer.Three of 9 control dogs. whose blood pressure (BP) was increased by more than 130 mm Hg, showed dye extravasation (BBB impairment) into brain tissue, but no extravasation was seen in the other 6 controls whose BP increase was less than 110 mm Hg.In 11 experimental animals, extravasation of Evans blue occurred in 8 of 9 resuscitated dogs after several minutes of cardiac arrest and in 1 of 2 nonresuscitated dogs. In the resuscitated dogs, the maximum systolic BP (peak BP) after restoration of ventricular function ranged from −40 to +210 mm Hg compared to control values. They showed all grades of dye extravasation without significant correlation between the magnitude of BP increase and the severity of dye extravasation.The authors conclude that BBB disruption usually occurs during CPR and causes plasma protein extravasation into brain tissue.Arterial hypertension is a causative factor for BBB disruption, as was seen in the control dogs. In resuscitation, restoration of BP sufficient to overcome intracranial pressure and maintain cerebral blood flow may be high enough to induce BBB disruption because cerebral vessels are fully dilated and functionally impaired due to longstanding anoxia. The rapidity of BP increases after restoration of ventricular function could be another factor which might contribute to BBB impairment.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Intracranial pressure (ICP) studies were carried out in 14 infants with severe birth asphyxia and brain damage. A markedly low cerebral perfusion pressure (CPP) was noted in infants who died and in 1 infant who survived with cerebral palsy. The long-term ICP tracings revealed negative waves and plateau waves in 2 infants. Cushing response was noted in 2 infants who had elevated ICP. The value and significance of evaluated CPP and of abnormal waveforms are discussed.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Despite important physiological functions, the fluctuations in plasma ionized calcium concentrations [Ca++] after major thermal injury have not been defined. Measurements of [Ca++] were undertaken in 25 patients of age ranging from 6–75 years, with body surface area burns of 25–85%. Plasma total calcium [Ca], inorganic phosphorus [Pi] and magnesium [Mg++] were also followed. Urinary excretion of the same ions was quantified in nine patients for the first 6 days postburn. The control group consisted of 12 patients who had sustained a similar injury at least 16 months earlier. Significantly low [Ca++] persisted throughout the observation period, despite an average replacement of 0.2 mM/kgμday of CaCl2. The initial hypophosphatemia and hypermagnesemia tended toward normal during the latter phase of the injury. Urinary excretion of the cations was not significantly elevated in the first 6 days postburn. The usual reciprocal relationship between [Ca] and [Pi] was not evident, and there was no correlation between [Ca++] and the size of burn. The use of McLean-Hastings nomogram poorly predicted the [Ca++] from [Ca]. Our data indicate that marked alterations in [Ca++] homeostasis occur after thermal injury. The etiology of hypocalcemia remains to be elucidated; the physiological consequences in terms of hemodynamic function deserve further study.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The cerebral function monitor (CFM) is a portable electronic device that processes and records bipolar cortical electrical signals derived from two parietal scalp electrodes. Specific filtering and electronic rectification permit tracings of high quality to be obtained at any location, even where electrical interference and personal movements may render the conventional EEG difficult to interpret. In a comparison study of patients with clinically apparent brain death, CFM tracings that revealed no cerebral electrical activity correlated perfectly with isoelectric EEGs performed in a neurophysiology laboratory in 10 patients who manifested signs of absent brain stem function, apositive 3-min apnea test, and severe hypotension. All patients had a terminal cardiac arrest within 17 days of onset of coma; the mean survival time was 9 days. Thus, a strong though presumptive diagnosis of brain death may be made in those patients with absent electrical activity on the CFM and evidence of absent brain stem, i.e., respiratory center, function.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The hypoxemia, elevated vascular pressures, and cardiac arrhythmias occurring during endotracheal suction may be related both to suction and the interruption of ventilation during suction. Although effects of suction vs. apnea have been compared in healthy patients, interruption of ventilation for purely investigational purposes precludes such a study in critically ill patients. Thus, in the present study, cardiovascular and blood gas changes attendant to endotracheal suction or equivalent periods of apnea were compared in anesthetized, paralyzed dogs in acute respiratory failure induced by oleic acid. Suction of 45-sec duration during interruption of intermittent positive pressure ventilation (IPPV) was associated with decreases in Pao2, pH, and heart rate and increases in Paco2, cardiac output, pulmonary arterial and systemic arterial pressure. These changes were not different from those observed during interruption of ventilation (apnea) alone. Cardiovascular and blood gas changes were also similar when suction and apnea were compared during interruption of continuous positive pressure ventilation (CPPV). Neither apnea nor suction was associated with cardiac arrhythmias.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

A nomogram has been prepared that depicts relationships between cardiac output (Q), oxygen consumption Vo2), hemoglobin concentration (Hb) the position of the oxygen-hemoglobin dissociation curve, the oxygen saturation of arterial blood (Sao2), and the partial pressure of oxygen in the mixed venous blood (Pvo2). Examples are provided to illustrate how this nomogram may be employed to facilitate decisions regarding the need for blood transfusions in patients in whom oxygen delivery may be impaired.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Nine of 10 adults, previously healthy patients who suffered cardiac arrest during or after anesthesia, recovered nearly complete neurological function when given iv phenytoin, 7 mg/kg. Phenytoin was given only after spontaneous heart beat and systolic blood pressure > 100 mm Hg had been restored and the diagnosis of neurological deficit had been established on the basis of unconsciousness, dilated and areflexic pupils as well as rigid and/or decerebrated posture. One patient recovered only partially, and eventually succumbed to other complications.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Patients on ventilators for respiratory failure due to pulmonary disease may develop three major complications requiring general surgical evaluation: gastrointestinal (GI) bleeding, paralytic ileus, and mesenteric vascular insufficiency. GI bleeding from acute hemorrhagic gastritis (stress ulceration) can be avoided by aggressive medical therapy consisting of volume replacement, antacids, nutrition, and treatment of the precipitating causes. When conservative therapy fails, surgery will be needed to control bleeding. Intestinal ileus is of uncertain etiology. Initially, it is treated conservatively. Rarely, when the patient develops peritoneal irritation or a cecal diameter of greater than 9 cm, surgery is indicated. Mesenteric vascular insufficiency of the nonocclusive type occurs in elderly individuals with heart disease, who develop a low cardiac output syndrome. Therapy must consist of avoiding a low flow state with proper fluid management, cardiorespiratory care, and drug therapy. Surgical intervention is indicated when physical examination and laboratory data point to a loss of intestinal viability.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The Bain circuit, a modified Mapleson D system, is a lightweight, simple circuit which has been used primarily for anesthesia. This report describes its use for long-term mechanical ventilation for infants and children. The use of this circuit improved warming of inspired gas reducing patient heat loss and, additionally, it was believed to have resulted in increased humidity of the inspired gas. There were no instances of accidental extubation nor were any of the endotracheal tubes blocked by inspissated secretions. Temperatures of the humidifiers had to be lower than conventionally recommended but this did not result in any nosocomial infections. This circuit is an effective and safe circuit to use for long-term mechanical ventilation of children.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID