Showing papers in "Critical Care Medicine in 1979"

Relative importance of alpha and beta adrenergic receptors during resuscitation.

Abstract: Successful resuscitation from cardiac arrest in the asphyxiated dog model has been ascribed to the use of artificial ventilation, closed chest cardiac massage, and administration of a vasopressor. Controversy remains over whether the most commonly employed vasopressor, epinephrine, exerts its effects primarily by elevating diastolic pressure and reestablishing coronary flow, or by exciting cardiac pacemaker cells and enhancing myocardial contractility. To observe pure alpha and beta adrenergic receptor influences during resuscitation, three groups (alpha-blocked, beta-blocked, unblocked) of dogs were studied. beta-blocked dogs resuscitated with phenylephrine and unblocked dogs resuscitated with epinephrine experienced 100% successful resumption of spontaneous circulation after 5 min of asphyxia-induced arrest. Only 27% of alpha-blocked animals resuscitated with isoproterenol were successfully revived. The appearance of the ECG during cardiac arrest and resuscitation could in no way be used to predict the outcome of resuscitation attempts. Results suggest that, initially, alpha receptor stimulation with concomitant diastolic pressure elevation is more important to the success of resuscitation than beta receptor stimulation.

Herbert Shubin Memorial Lecture. Right and left ventricular geometry: adjustments during acute respiratory failure.

Abstract: “Truth captured loses its glamor; truths long known and widely believed have a way of turning false with time; easy truths are a bore and too many of them become half truths.” R, Hofstadter, in “Anti-Intellectualism in American Life,” 1962.

Evaluation of the biologic importance of various hemodynamic and oxygen transport variables: which variables should be monitored in postoperative shock?

Abstract: In a series of 113 consecutively monitored, critically ill postoperative patients, predictive coefficients for each monitored hemodynamic and oxygen transport variable (parameter) were determined based on their ability to predict outcome at each stage of postoperative shock. As this predictive coeff

Effects of hypoxia and shock on transcutaneous PO2 values in dogs.

Abstract: Transcutaneous Po2 (PtcO2) was measured with transcutaneous oxygen electrode sensors and correlated with Pao2, Pvo2, cardiac output, and O2 delivery during changes in FIO2 and standardized hypovolemic shock in anesthetized dogs. Simultaneously, cardiorespiratory variables were measured: intravascula

The systemic septic response: does the organism matter?

Abstract: The clinical and physiological responses to septicemia were evaluated in 59 patients with 70 septic episodes. All patients were critically ill, had similar ICU support, and had positive blood cultures as well as a clinical infection when studied by dye dilution cardiac outputs. The overall ratio of gram-negative to gram-positive sepsis was 2.6:1.0. Patients with septicemia caused by gram-positive organisms, gram-negative organisms, anaerobes, and fungi had similar fever, leucocyte, and acid-base responses. There were also no statistical differences in any physiological variables between organism group or between specific organisms. After volume loading, all patients exhibited a hyperdynamic cardiovascular response with abnormal vascular tone. Some degree of myocardial depression was a common feature of all forms of bacterial or fungal septicemia. Heart rate was the cardiac variable producing the increased cardiac output in this setting. The exact pathogenesis of the septic response remains undetermined. However, the response appears to be host determined and not peculiar to a specific pathogenic microorganism.

The Trendelenburg position: hemodynamic effects in hypotensive and normotensive patients.

Abstract: The effect of the Trendelenburg position on systemic and pulmonary hemodynamics in critically ill patients is not generally appreciated. This study examined the hemodynamic effect of 15–20° head-down tilt in 61 normotensive and 15 hypotensive patients with acute cardiac illness or sepsis. In normote

Studies in shock and resuscitation, I: use of a hypertonic, albumin-containing, fluid demand regimen (HALFD) in resuscitation.

Abstract: We have reevaluated and clinically tested the current concepts of shock and resuscitation on a logical, physiological, and physical basis. We have considered the currently accepted resuscitation paradigm which is based upon the thesis that early rapid resuscitation of "lost" fluid volume is mandatory and that adequacy of resuscitation can be evaluated by central venous pressure, PAP, PAWP, pulse rate, blood pressure, and/or urine volume. Such methods also accept as natural concomitants that capillary beds are "damaged by injury"; that they "leak" salt, fluid, and albumin; and that these are expected occurrences which are injury-related. We have also examined and clinically evaluated the thesis that MAP is a primary reflector of the relationships between volume and the size of the currently available functional vascular space. (Currently available functional vascular space is mediated through the baroreceptor (stretch receptor)/neuroendocrine mechanisms.) Under this hypothesis, fluid resuscitation comprises infusion of a volume per unit time given so as to replete currently measurable fluid losses and to normalize and/or sustain MAP and the normal osmolar and oncotic relationships at the capillary/tissue interface while holding hydrostatic pressure at normal. Using burn injury as a model, we compared statistically homogeneous, randomly selected groups of burn patients who were resuscitated using a hypotonic fluid (130 mOsm/liter) alone (group R: 7 patients), hypertonic fluid (240 mOsm/liter) alone group H: 5 patients), or the hypertonic fluid containing albumin (12.5 g/liter) (group A: 7 patients). The results indicate that significantly smaller volumes of fluid were needed to resuscitate the patients in group A with a significantly more rapid normalization of physical, physiological, and biochemical parameters. We conclude that the physically and physiologically appropriate method of resuscitation, demonstrated in burn injury, comprises the use of a fluid given at a rate: (1) to maintain mean arterial and hydrostatic pressures within normal range; (2) that delivers a volume per unit time which does not exceed the capacity of the currently available functional vascular space; (3) that replaces concurrent measurable fluid losses; (4) that is hypertonic (to normalize capillary/tissue osmotic gradients); and (5) that contains colloid (to normalize capillary/tissue osmotic gradients); and (5) that contains colloid (to normalize capillary/tissue oncotic gradients). We further conclude that salt, fluid, and colloid loss into the interstitium during resuscitation frequently is due to the rate delivered and/or the physical nature of the fluid used and not to capillary bed damage outside the zone of injury.

Cardiorespiratory monitoring in postoperative patients: I. Prediction of outcome and severity of illness.

Abstract: An index for prediction of outcome for use as a measure of the severity of illness was developed by a nonparametric multivariate analysis of cardiorespiratory data from 113 critically ill postoperative general surgical patients. This severity (predictive) index was based on a computerized algorithm that compares a given observed value with the frequency distributions of survivors and nonsurvivors. The difference in the mean values of this index for survivors and nonsurvivors was statistically significant (p less than 0.001) during each stage of shock. Sensitivity of the index in prediction of survival ranged from 70-93% depending upon stage, the specificity of the index ranged from 76-92%, and the predictive accuracy ranged from 87-96%. The severity index is used as a process measure to track the course of critically ill patients and to evaluate the efficacy of alternative therapies.

Comparison of hemodynamic, pulmonary, and renal effects of use of three types of fluids after major surgical procedures on the abdominal aorta.

Abstract: Hemodynamic, pulmonary, and renal variables were measured in 24 patients scheduled for major abdominal aortic operations. Control values were obtained before preoperative medications were given. All patients received 5% dextrose in Lactated Ringer's solution intraoperatively. Postoperatively, group 1 patients received 5% dextrose in water plus albumin, group 2 received 5% dextrose in 0.45 sodium chloride solution, and group 3 received 5% dextrose in lactated Ringer's solution. There were significant increases in Qs/Qt and AaDO2, 48 hours after operation in group 3. Oxygen consumption and cardiac output increased in all groups 24 hours after operation. Twenty-four hours later, these two variables returned to control values in group 1 but continued to rise in the other two groups. Significant diuresis occurred in group 1, 48 hours postoperatively, whereas the other two groups continued to retain water. Use of albumin and 5% dextrose in water in the postoperative period seemed to produce less deviations from control values of most measured variables, than the other two groups.

The inverse relationship between cost and survival in the critically ill cancer patient.

Abstract: The enormous cost of intensive multiple organ system support is apparent from patient or third party charges of $1500--$2000 per day exclusive of physician fees sampled during a retrospective review of 700 consecutive recent admissions to the Critical Care Facility of Memorial Cancer Center. Mortality rates of 49% for general medical, 54% for lymphoma or leukemia, and 20% for surgery patients suggest the need for a selective admission and discharge policy which concentrates financial and personnel resources on those for whom there remains a reasonable chance of worthwhile palliation, if not cure, of their malignancy. An informal policy of this kind may have contributed to a 10% increase in hospital discharges and a reduction of in-unit mortality from 22--18% when compared to 1035 earlier unselected admissions. A modified version of the classification suggested by the Critical Care Committee of the Massachusetts General Hospital has been adopted for use at this institution. A similar approach by other cancer centers is urged so that predictive indices based on prognosis of the underlying disease as well as physiological status may be developed. Otherwise, cost-benefit analysis by third party payers or government will become an unavoidable, and less satisfactory, alternative.

Renal failure in the respiratory intensive care unit.

Abstract: The development of renal failure during respiratory failure is of grave prognostic significance. In 686 patients with respiratory failure, 74 developed renal failure; these had a mortality of 80%. The leading predisposing factors are: 1) gastrointestinal bleeding with hypovolemic shock; 2) sepsis wi

Tetanus: a review.

Abstract: Tetanus is caused by the organism Clostridium tetani, which produces tetanospasmin, a neurotoxin responsible for the clinical manifestations of muscle rigidity and reflex spasms. The majority of cases follow an anaerobic wound infection associated with trauma. Incubation period is usually 3 days to 3 weeks. 75% of patients present with trismus. Reflex spasms are seen in 70% of patients and characterize the severity of the disease. Treatment involves removal of the offending organism, neutralization of free neurotoxin, controlling rigidity and reflex spasm, and minimizing complications. Diazepam may be used alone in mild cases. Severe cases require the addition of nondepolarizing neuromuscular blocking agents and mechanical ventilation. Respiratory complications occur early and require aggressive airway management. A serious, late complication is the syndrome of sympathetic nervous system overactivity that is treated with alpha and beta blockade. High mortality rates seen in the United States may be due to delays in diagnosis and lack of familiarity with treatment. The disease is preventable with adequate immunization.

Automated method for determination of oxygen equilibrium curves of red cell suspensions under controlled buffer conditions and its clinical applications.

Abstract: The accurate determination of the oxygen equilibrium curve (OEC) of whole blood or red cell suspensions requires special considerations to avoid the secondary effects due to lactate formation, removal of carbon dioxide, use of anticoagulants, etc. An automated apparatus has been constructed that can record the whole OEC of red cells within 20 min. The instrument also can be used to record the OEC of hemolysate. The pH, temperature, and PO2 are monitored constantly during the measurement. Using this instrument, the effects of pH, temperature, carbon dioxide, anticoagulants, and buffers on the OEC of normal fresh blood have been investigated. The OEC of normal blood, blood containing abnormal hemoglobin, or enzyme, were determined. The results were compared with those obtained using commercial OEC apparatuses.

Effect of dopamine on intrapulmonary shunt fraction and oxygen transport in severe sepsis with circulatory and respiratory failure.

Abstract: The hemodynamic response to a dopamine HCl infusion (10 microgram/kg per min) was measured in 25 adult patients with severe sepsis: there were 6 patients with circulatory hyperdynamic states, 9 patients with myocardial failure, and 10 with hypovolemia. Each patient also had acute respiratory failure. Changes of intrapulmonary shunt fraction (Qs/Qt), arterial and mixed venous oxygen tension (PaO2 and PvO2), oxygen transport, and oxygen consumption (VO2) were evaluated before and after dopamine infusion. Dopamine infusion produced clinical improvement and increased cardiac output. The hemodynamic response seemed to differ slightly according to the pattern of circulatory failure: chronotropic effect appeared to be predominant in hyperdynamic states, whereas inotropic effect appeared to be predominant in myocardial failure or hypovolemia. Moreover, in hypovolemic patients we noted a rise in pulmonary capillary wedge pressure suggesting an additional increase in venous return. During this treatment, we also noted a worsening of the Qs/Qt despite the increase in pulmonary blood flow; this worsening did not prevent significant improvements in VO2, but the improvement in PVO2 was offset by increased Qs/Qt and PaO2 remained unchanged.

Protein and caloric or macronutrient metabolic management of the critically ill patient.

Abstract: Aggressive and early use of nutritional support therapies in critically ill patients represents a major advance in critical care medicine. The net protein catabolism and erosion of protein stores which is characteristic of the metabolic response to injury results in significant added morbidity and mortality in critical care units. The early administration of appropriate protein and energy in support of enhanced demands will maintain host defense and preserve organ function, thus, allowing time for stabilization of clinical status while life support strategies are implemented. In all circumstances, protein, vitamins, minerals, and nonprotein calories must be provided within fluid and electrolyte restrictions and in conjunction with optimal hemodynamic and pulmonary support.

Physiological significance of oxygen dissociation curve shifts.

Abstract: The oxygen delivery system consists of multiple components balanced to provide optimal oxygen supply to all tissues and arranged such that an abnormality in one component is compensated by adjustments in others. Analysis of pertinent data indicates that leftward shifts of the oxygen dissociation curve (ODC) in normal animals and persons elicit adaptive changes in other components which sustain normal oxygen supply. By contrast, several recent studied indicate that leftward ODC shifts, when occurring in combination with other abnormalities of oxygen delivery, produce or aggravate hypoxia. These data suggest that the brain and heart are the organs particularly at risk. It is concluded that leftward ODC shifts, due to massive transfusion of stored blood and to hyperventilation of unconscious patients, are most likely to be hazardous in the presence of poor perfusion, coronary artery disease, or cerebrovascular disease.

Fluorescence mapping of mitochondrial redox changes in heart and brain.

Abstract: Fluorescence techniques may be utilized to map changes in the distribution of mitochondrial redox states in heart and brain during ischemic or hypoxic stress. The basis of these techniques is the intrinsic fluorescence of reduced NADH and oxidized flavoprotein in mitochondria which respond to changes in critical oxygen supply. Ischemic areas in rabbit hearts induced by coronary ligation were detected and mapped based on the increase in NADH fluorescence in the ischemic zone. The width of the jeopardized normoxic tissue surrounding the ischemic area (less than 50--350 mu) was measured by combination of fluorescein angiography and NADH fluorescence. Areas of increased NADH fluorescence in gerbil brains after carotid artery ligation or induction of spreading depression were mapped in a similar manner. Intraoperative monitoring of flavoprotein fluorescence from human cerebral cortex after superficial temporal artery middle cerebral artery (STA-MCA) anastomoses demonstrated increased rates of cortical oxidative metabolism after the surgical procedures.

Stability of the arterial/alveolar oxygen partial pressure ratio. Effects of low ventilation/perfusion regions.

Abstract: The alveolar-arterial oxygen partial pressure difference (AaDO2) and the arterial/alveolar oxygen partial pressure ratio (a/APO2) were compared for stability when inspired oxygen concentration (FIO2) changed. The analysis was based on a three-compartment lung model and experimental results in 10 pat

Hypoxemia during hemodialysis

Abstract: Five mechanically ventilated patients were studied during hemodialysis. The aim was to determine if hypoxemia would develop, and to identify the causes. Respiratory variables (dynamic compliance, peak airway pressure, CO2production); oxygen uptake, and transport variables (alveolar and arterial PO2, pulmonary venous admixture, oxygen consumption); respiratory quotient; pulmonary vascular resistances and white blood cells (WBC) were measured. PaO2 decreased during dialysis, as did PaO2. However, the fall in alveolar oxygen tension failed to explain the hypoxemia. Lung volume did not change significantly, because dynamic compliance, peak airway pressure, and pulmonary vascular resistance were not modified. CO2 losses through the dialysis coil were of little clinical significance. WBC count fell significantly. The authors conclude that ventilation/perfusion and diffusion abnormalities related to leuko-agglutination are responsible for hypoxemia during dialysis.

Hyperventilation in tricyclic antidepressant poisoning.

Abstract: A patient with severe tricyclic antidepressant poisoning who showed recurrent ventricular fibrillation and wide QRS complexes on the ECG, failed to respond to intravenous physostigmine and lidocaine. Deliberate artificial hyperventilation was immediately effective in preventing further arrhythmia an

Pulmonary interstitial gas: first sign of barotrauma due to PEEP therapy.

Abstract: Radiographic identification of pulmonary interstitial gas is a prime indicator of possible further complications in patients treated with PEEP therapy for severe respiratory failure. Records and chest radiographs of 89 adult patients treated with PEEP in a 40-month period were reviewed. Data of 7 were incomplete, 82 cases were analyzed. Of 17 patients who developed interstitial gas, 9 progressed to further barotrauma complications of pneumomediastinum, pneumothorax, and extrathoracic dissection. Interstitial gas is manifested radiographically by vesicular rarefactions (cystic changes), linear streaks along the bronchi and vessels, halos of gas around vessels, and subpleural gas.

Effects of closed-chest cardiac massage on intracranial pressure.

Abstract: Closed-chest cardiac massage results in a marked increase in intrathoracic pressure and unusual patterns of blood flow. Among the physiological consequences of these changes appears to be a marked increase in intracranial pressure associated with chest compression as documented by the following patient case studies. While temporary, the marked nature of this rise in intracranial pressure suggests that the technique of closed-chest massage may, in itself, be responsible for clinically significant alterations in cerebral hemodynamics.

Multisystem failure: a review with special reference to drowning

Abstract: Near-drowning represents an insult that can affect all organ systems. A common pathway for injury is hypoxemia, acidosis, and hypoperfusion. Pulmonary insufficiency and CNS dysfunction are major causes of morbidity and mortality. Variations in vascular volume, heart failure, renal failure, coagulation disorders, and electrolyte disturbances may also be present. Patients should be observed for multisystem failure and therapy tailored to the particular needs of each victim.