Showing papers in "Critical Care Medicine in 1987"

Serial cardiovascular variables in survivors and nonsurvivors of human septic shock: heart rate as an early predictor of prognosis.

Abstract: Forty-eight septic shock patients with positive blood cultures had conventional serial hemodynamic evaluations until recovery or death to identify early cardiovascular variables that predicted outcome. There were 19 (40%) survivors and 29 nonsurvivors. At the initial evaluation, both survivors and nonsurvivors demonstrated an elevated cardiac index (CI), low systemic vascular resistance index (SVRI), and normal stroke volume index. However, only an initial heart rate (HR) less than 106 beat/min significantly predicted survival. Twenty-four hours after the onset of shock, both an HR less than 95 beat/min and an SVRI greater than 1529 dyne.sec/cm5.m2 predicted survival. Comparing the hemodynamic profiles from the initial to the 24 h time point, a decrease in HR greater than 18 beat/min or a decrease in CI greater than 0.5 L/min.m2 predicted survival. Twenty-two deaths occurred in the first week of study, of which 18 (82%) were due primarily to low SVRI and four (18%) to low CI. Seven deaths occurred after 1 wk, all of which were due to multiple organ failure.

Predictive value of the stomach wall pH for complications after cardiac operations: comparison with other monitoring.

Abstract: The ability to predict impending complications after elective cardiac operations from measurements of BP, cardiac index, arterial pH, and urine output on the day of operation was compared with that of indirect measurement of stomach wall pH in 85 patients. We found that acidosis in the stomach wall

Airway Pressure Release Ventilation

Abstract: Traditional mechanical ventilation effects inflation of the lungs by increasing airway pressure above the ambient. Positive pressure lung inflation reverses the physiological variations in airway and intrathoracic pressure that occur during a normal spontaneous respiratory cycle. Such a fundamental alteration in cardiopulmonary mechanics frequently leads to complications and therapeutic compromise (Montgomery et al. 1985). High airway and intrathoracic pressure during positive pressure breaths does not allow adequate restoration of functional residual capacity with the use of continuous positive airway pressure (CPAP) and, consequently, prevents optimization of gas exchange and lung mechanics (Katz and Marks 1985; Kirby et al. 1975). Increased work of spontaneous breathing and impaired matching of ventilation and perfusion diminish the efficiency of ventilation, thereby leading to an increase in the requirement for mechanical ventilatory support (Froese and Bryan 1974; Wolff et al. 1986). Even when the ventilator is adjusted carefully, positive pressure ventilation (PPV) will elevate mean intrathoracic pressure and result in cardiovascular compromise in patients with normal or low intravascular volume. Periodic alveolar hypertension may cause barotrauma in compliant areas of the lung, may impair healing of the lung, and may even cause additional iatrogenic damage in the diseased alveoli.

A reappraisal of norepinephrine therapy in human septic shock

Abstract: The effectiveness and safety of iv infused norepinephrine (0.5 to 1 microgram/kg X min) were evaluated in 12 hyperdynamic vasodilated septic patients, who remained hypotensive despite iv volume expansion and antimicrobial and dopamine therapy. During norepinephrine infusion, mean arterial pressure and systemic vascular resistance index increased (p less than .001) and heart rate decreased (p less than .02). Cardiac index either increased or was unchanged in ten patients and decreased slightly in the remaining two patients. Urine flow increased (p less than .01) and was more than 0.5 ml/min when a critical renal perfusion pressure was reached if renal damage was not overwhelming. We conclude that norepinephrine may improve arterial BP and urine flow when volume replacement and dopamine therapy have failed to reverse the hypotension of septic shock.

A simple technique to accurately determine intra-abdominal pressure.

Abstract: The determination of intra-abdominal pressure (IAP) may be useful in a variety of clinical situations. Despite this, invasive IAP monitoring is seldom performed due to the risks involved. Using a standard canine model of increased IAP, we evaluated the accuracy of transurethral bladder catheter pres

Bedside evaluation of right ventricular performance using a rapid computerized thermodilution method.

Abstract: In 34 patients, we assessed the reproducibility and accuracy of a new, computerized, thermodilution method that determines right ventricular ejection fraction (RVEF). We compared the results from this new algorithm with simultaneous results from the conventional plateau thermodilution method and fro

Oxygen delivery and consumption in patients with hyperdynamic septic shock.

Abstract: We analyzed the relationship of increases in oxygen delivery to changes in oxygen consumption in ten patients with hyperdynamic septic shock. Increases in oxygen delivery from 413 ± 14 (SEM) to 535 ± 19 ml/min-m2 (p < .01) were associated with increases in oxygen consumption from 136 ± 10 to 161 ± 5

Directly measured tissue oxygen tension and arterial oxygen tension assess tissue perfusion.

Abstract: Mean subcutaneous tissue Po2 (Psqo2) measurements were obtained in dogs with an unheated electrode placed in an implanted Silastic tonometer, while Pao2 was increased in increments from 40 to 600 torr during normal, increased, and reduced blood volume. These changes reflect that the mean Psqo2 is ap

Medical patients at high risk for catastrophic deterioration.

Abstract: The objective of this study was to develop criteria to demarcate patients at risk for catastrophic deterioration (arrest or major decompensation) and those likely to require intensive care. From an inception cohort of patients admitted to the medical service, 544 patients were evaluated prospectively for severity of illness and stability by the admitting residents; the course of patients was reviewed blindly by observers. Patients admitted with acute dyspnea, particularly those with chronic pulmonary disease, were at a significantly greater (p less than .01) risk of arrest. All but one of the other arrests occurred in patients who were rated unstable on admission and who had further deterioration of pre-existing problems in the hospital (p less than .0001). The deterioration rates were highest among patients rated as unstable, particularly in patients with comorbid disease. Patients who are unstable on admission or who begin to deteriorate due to comorbid disease or the condition leading to admission, should be considered at extremely high risk for subsequent arrest and should be admitted to critical care units for early observation.

Acute phase protein response to tissue injury.

Abstract: Macrophages activated at sites of tissue injury produce interleukin-1, which induces hepatocytes to synthesize acute phase proteins (APP). Daily serum levels of C-reactive protein (CRP), haptoglobin (HPT), transferrin (TRF), alpha-1 antitrypsin, and ceruloplasmin (CER) were measured in 60 patients, 30 having inguinal herniorrhaphy (H), 18 cholecystectomy (C), and 12 major abdominal trauma (MAT). APP response was proportional to the level of tissue injury. CRP rose in all groups, MAT greater than C, which was greater than H. HPT levels were depressed in MAT, presumably due to removal of hemoglobin-HPT complexes from the serum. TRF was severely depressed in MAT and may be implicated in the higher infection susceptibility in this group. CER was elevated in C, suggesting a stimulating mechanism in this group as opposed to H and MAT. Explanation for this is unknown. APP changes, especially CRP, may be useful as markers of the amount of tissue damage.

Twenty-four hour energy expenditure in critically ill patients.

Abstract: Resting energy expenditure (EE) is often used as the basis of nutritional support for critically ill patients but whether resting EE is representative of total daily EE is not known. EE was measured for 24 h in ten mechanically ventilated, critically ill patients (average Acute Physiology and Chronic Health Evaluation II score 23) to determine EE, resting EE, and the energy expended during various ICU activities. Although activities, such as weighing the patient on a sling-type bed scale, repositioning, and chest physiotherapy resulted in dramatic EE increases above resting levels (36%, 31%, and 20%, respectively), the actual contribution of these activities to total EE was small (1.1%, 2.1%, and 3.6%, respectively). The mean measured resting EE was 47.3 +/- 22.3% above mean predicted EE based on the Harris and Benedict equation, and the mean total 24-h EE was 6.9 +/- 2.6(SD)% above the mean measured resting EE. In this group of mechanically ventilated, critically ill patients, an activity factor of no greater than 10% above resting EE is appropriate.

Efficacy of intensive care for bone marrow transplant patients with respiratory failure.

Abstract: We reviewed the ICU courses of 50 bone marrow transplant recipients treated for respiratory problems. Seven of nine postoperative patients survived compared to one of 40 patients with progressive interstitial pneumonia. Nonsurvivors accounted for 94% of the ICU days, 98% of intubated days, and 99% of blood products used. All survivors were extubated within 4 days. Intensive respiratory care is effective for patients with readily reversible causes of respiratory failure, but is generally futile for patients with progressive interstitial pneumonia. We recommend providing these patients with realistic prognostic estimates early in their treatment.

Prediction of outcome after cardiac arrest.

Abstract: Neurologic outcome of hypoxic ischemic coma after cardiac arrest was studied in 32 patients. Observations were made and samples collected 24 and 48 h after the ischemic insult. The Glasgow-Pittsburgh coma score was assessed for its prognostic value. Other variables studied were the EEG and adenylate kinase, lactate and glutathione in the cerebrospinal fluid (CSF). Outcome was termed good if the patients resumed an independent life within a 6-month follow-up period. The closest correlations between prediction and good outcome occurred with the Glasgow-Pittsburgh coma score (94%) and the EEG (77%) at the 48-h examination, a modified coma score (96%) at 48 h, and CSF lactate (78%) at 24 h. Some simple neurologic signs (e.g., no withdrawal response to pain) at stated points in time was 100% associated with a bad outcome, although their absence was not associated necessarily with a good prognosis.

Comparison of blood gases of ventilated patients during transport.

Abstract: Three modes of ventilation during the transport of 30 ventilator-dependent patients were compared using blood gas variables. Ten were ventilated with a manually operated, ventilation bag (group C) and ten with a tidal volume meter at the exhalation valve of the ventilation bag (group V). Another ten

Monitoring in anesthesia and critical care medicine

Abstract: Part 1 General principles: a philosophy of monitoring the senses as monitors precordial and esophageal stethoscopes monitoring and patient safety cost benefit analysis on monitoring. Part 2 Cardiovascular system: noninvasive blood pressure monitoring invasive blood pressure monitoring electrocardiographic monitoring central venous pressure monitoring the Swan-Ganz catheter - past and present pulmonary artery catheterization transesophageal data collection. Part 3 Monitoring the respiratory system: respiratory monitoring monitoring anesthetic and respiratory gases blood gas monitoring pulse oximetry. Part 4 Monitoring and the central nervous system: the electroenecephalogram evoked potential monitoring monitoring intracranial pressure. Part 5 Miscellaneous monitoring: temperature monitoring monitoring the kidney and urine miscellaneous blood measurements monitoring the anesthetic delivery system monitoring the neuromuscular junction the computer in anesthesia monitoring in unusual environments. Part 6 Monitoring and subspecialities: monitoring in neuroanesthesia monitoring in cardia anesthesia monitoring in the pediatric patient monitoring in obstetric anesthesia monitoring in the intensive care setting monitoring modalitites of the future.

Evaluation of esophageal tracheal combitube in cardiopulmonary resuscitation.

Abstract: Prompt establishment of an airway is a primary goal in CPR of nonbreathing and unconscious patients. The esophageal tracheal combitube (ETC) is a new airway, designed for emergency intubation providing sufficient ventilation whether the airway is placed into the trachea or into the esophagus. We evaluated the effectiveness of the ETC in 31 patients during CPR. Blood gas analyses obtained during esophageal placement of the ETC showed results comparable to those of ventilation with a conventional endotracheal airway (ETA). The ETC appeared to oxygenate and ventilate patients adequately without complications. The efficacy, safety, and ease of insertion ensure rapid airway control. It is concluded that the ETC provides a sufficient alternative to the ETA whenever ideal conditions or trained staff for endotracheal intubation are not immediately available.

Dependence of oxygen consumption on cardiac output in sepsis.

Abstract: We studied the relationship between oxygen consumption (Vo2) and cardiac output in 17 hemodynamically stable, septic and eight nonseptic ICU patients. Each received 300 ml of fresh-frozen plasma or 25% albumin with up to 500 ml of crystalloids, in addition to regular maintenance fluids; this treatment increased pulmonary wedge pressure (WP) by 3 to 4 mm Hg. Measurements were performed before and after approximately 5 h of volume loading. Because cardiac index (CI) decreased as WP increased in four septic and three nonseptic patients, we grouped the data according to the state of flow instead of the recording time sequence. From low to high flows, mean CI increased in septic patients and nonseptic patients. Oxygen delivery (Do2) increased in septic and nonseptic patients. Vo2 remained unchanged in nonseptic patients, while it increased in septic patients. Accordingly, arteriovenous oxygen difference narrowed in nonseptic patients from 4.46 +/- 1.62 to 3.59 +/- 1.21 ml/dl (p less than .05) but did not change in septic patients. In the septic group, the difference in CI between high and low flows was significantly (p less than .05) greater in survivors than in nonsurvivors. We conclude that the septic state is accompanied by a peripheral oxygen deficit, which can be partially reversed by maintaining an above-normal CI and Do2.

Hemodynamic patterns of meningococcal shock in children.

Abstract: Meningococcal shock still is associated with high mortality. Along with antibiotics and control of metabolic derangements, standard therapy involves monitoring and maintaining numerous cardiorespiratory variables. From 1980 to 1985, 39 children with meningococcal shock were treated in our pediatric ICU. We obtained full hemodynamic monitoring in 18 (12 survivors, six nonsurvivors). Two hemodynamic patterns were observed: hypovolemia and cardiac failure. Early death was generally related to refractory hypovolemia, probably secondary to severe capillary leak. Survival usually occurred when noticeable cardiac failure was controlled with early use of catecholamines and judicious fluid management. Because cardiac failure only slowly recovered, a therapeutic approach that aims not at normal variables but, rather, at survival variables seems appropriate.

D-erythro-neopterin plasma levels in intensive care patients with and without septic complications

Abstract: The activation of macrophages is accompanied by release of 2-amino-4-oxo-6(D-erythro-1',2',3'-trihydroxypropyl)-dihydropterid ine (D-erythro-neopterin). The neopterin levels of 21 patients were measured with radioimmunoassay. The patients were classified according to the clinical course and outcome. We found highly significant differences between survivors and nonsurvivors for each of the evaluated days of the observation period. In addition to a sustained increase, patients with fatal outcome always showed a higher percentage of neopterin levels (88.2 +/- 28 [SD]%) exceeding the upper confidence limit (27.4 nmol/L) than survivors (31.8 +/- 29.9%). We conclude that the assessment of D-erythro-neopterin might be an easily available aid for an early evaluation of the immunologic status of a patient at risk for septic complications.

Critical level of oxygen delivery after cardiopulmonary bypass.

Abstract: The relationship between oxygen uptake (Vo2) and delivery (Do2) was examined in 64 patients immediately after cardiopulmonary bypass. In 44 patients with lactate levels below 2.5 mmol/L, Vo2 decreased proportionally when Do2 decreased below 300 ml/min X m2. At a Do2 over this level, Vo2 plateaued at 105 +/- 13 (SD) ml/min X m2. In a contrasting group of 22 patients with blood lactate levels above 2.5 mmol/L, Vo2 changes depended on changes in Do2 both alone and below 300 ml/min X m2.

Validation of the mortality prediction model for ICU patients.

Abstract: We tested recently developed admission and 24-h models of hospital mortality on 1,997 consecutive admissions to a general medical/surgical ICU. This study population was independent of the group used to develop the models. The admission prediction model estimated each patient's probability of hospit

Relationship of somatomedin-C/insulin-like growth factor I levels to conventional nutritional indices in critically ill patients.

Abstract: Twenty ICU patients, with varying diagnoses and degrees of catabolism, were studied prospectively to determine whether somatomedin-C/insulin-like growth factor I (SMC/IGFI) is related to the conventional nutritional indices, plasma prealbumin, transferrin and albumin, and nitrogen balance (NB) in critical illness. Mean SMC/IGFI concentration in these critically ill patients was below the lower limit of the reference range. SMC/IGFI concentrations correlated with NB for the 24 h before measurement (r = .38, p less than .01) and with cumulative NB for the previous 2 (r = .50, p less than .01), 3 (r = .34, p less than .05), and 5 days (r = .46, p less than .05). Prealbumin correlated with cumulative 5-day NB (r = .39, p less than .05). Plasma albumin and transferrin concentrations did not correlate with NB for any of these time periods. SMC/IGFI concentrations correlated with cumulative protein (r = .59, p less than .01), carbohydrate (r = .63, p less than .01), and energy intake (r = .64, p less than .01). SMC/IGFI was the only index which consistently correlated with NB. We conclude it is a useful index of nutritional status in critically ill patients.

Thermodilution determination of right ventricular volume and ejection fraction: a comparison with biplane angiography.

Abstract: In 13 patients without tricuspid incompetence, we compared the values of right ventricular ejection fraction (RVEF) and right ventricular end-diastolic volume (RVEDV) obtained with biplane angiography and thermodilution at end-inspiration. A modification of Simpson's rule was used to measure angiographic volumes, and a new pulmonary artery catheter equipped with a rapid response thermistor was used to measure the ejection fraction by the Holt plateau method. The correlation between the two methods was acceptable (r = 0.83 for RVEF, r = 0.71 for RVEDV) despite the limitations of both angiography and thermodilution. Thermodilution underestimated RVEF and overestimated RVEDV when compared to angiography. The variation coefficient with thermodilution for five measurements of the RVEF per patient was 12 +/- 5%. In addition to pressure and cardiac output measurements, monitoring of RVEF and RVEDV in the ICU should be possible with such a catheter. Further work is needed to assess the clinical relevance of these added data and their use for optimizing the therapy of right ventricular failure in acutely ill patients.

A comparison of methods to predict mortality of intensive care unit patients.

Abstract: This paper presents results of the first study explicitly designed to compare three methods for predicting hospital mortality of ICU patients: the Acute Physiology Score (APS), the Simplified Acute Physiology Score (SAPS), and the Mortality Prediction Model (MPM). With respect to sensitivity, specificity, and total correct classification rates, these methods performed comparably on a cohort of 1,997 consecutive ICU admissions. In these patients from a single hospital, the APS overestimated and the SAPS underestimated the probability of hospital mortality. The MPM probabilities most closely matched the observed outcomes. Each method holds considerable promise for assessing the severity of illness of critically ill patients. The MPM should be particularly useful for comparing ICU performance, since it is independent of ICU treatment and can be calculated at the time a patient is admitted.

Clinical characteristics and resource utilization of ICU patients: implications for organization of intensive care.

Abstract: We reviewed the clinical characteristics and resource utilization of 391 medical (M) and 315 surgical (S) ICU patients. In general, MICU patients had more physiologic derangement, as determined by the admission, maximal, and average acute physiology scores (APS). SICU patients had more frequent therapeutic interventions as measured by admission, maximal, and average therapeutic intervention scoring system values. Notably, 40% of MICU and 30% of SICU patients never received any active interventions and were admitted strictly for monitoring purposes. Patients on admission with APS less than or equal to 10 had markedly shorter ICU stays, with almost 50% less treatment than patients with APS over 10. Fifty-six percent of patients with APS less than or equal to 10 did not require any active intervention. In contrast, 83% of patients with APS greater than 10 had considerable intensive interventions. These patients required mechanical ventilation, invasive monitoring, and vasoactive drugs more than twice as often as patients with lower APS scores. Consideration should be given, therefore, to the organization of ICUs according to the patient's severity of illness.

Hypermetabolic response after hypothermic cardiopulmonary bypass.

Abstract: Sixteen patients undergoing hypothermic cardiopulmonary bypass for open heart surgery were studied prospectively. Oxygen consumption and CO2 production showed a marked increase during the first 6 h postoperatively. Consequently, the measured resting energy expenditure was markedly elevated compared to the predicted energy expenditure. This hypermetabolic response occurred simultaneously with maximum spontaneous rewarming after the end of surgical procedures. Ventricular function was low throughout the postoperative period, and no cardiac response to increased energy requirements was recorded. On the contrary, marked increases in arteriovenous oxygen and CO2 difference were observed during the period of highest resting energy expenditure. We conclude that the first hours after hypothermic cardiopulmonary bypass represent the period of highest risk for decompensation. The continuous monitoring of CO2 production is suggested as a useful clinical method to detect postoperative changes in metabolic rate.

Resuscitation with 7.5% NaCl in 6% dextran-70 during hemorrhagic shock in swine: effects on organ blood flow.

Abstract: We previously reported that small volume infusions of 75% NaCl in 6% dextran-70 (HSD) are superior to equal volumes of normal saline (NS) or 75% NaCl in the ability to resuscitate animals from an otherwise lethal hemorrhage In the present experiment, we evaluated organ blood flow in unanesthetized swine bled 46 ml/kg in 15 min and subsequently infused with a volume of HSD (n = 5) or NS (n = 5) equal to 25% of the shed blood Radiomicrospheres were injected before hemorrhage, immediately after hemorrhage, and 5 and 30 min after treatment At the end of hemorrhage, cardiac output had fallen to one-third of baseline values Five minutes after the infusion of HSD, cardiac output had returned to baseline levels, while cardiac output in the NS-treated controls had increased to only one-half of prehemorrhage values Blood flows to the brain, diaphragm, skin, muscle, and fat were not different between the two groups Infusion with HSD, however, produced flows to the myocardium, kidneys, liver, small intestine, and pancreas that were significantly greater than post-hemorrhage and NS-treated control values NS was unable to increase these flows significantly above post-hemorrhage levels We conclude that small volumes of HSD can significantly improve organ blood flow after hemorrhagic shock This improvement in flow may explain the increased survival observed with this solution and may attenuate some of the later complications of hemorrhagic shock

Hypoalbuminemia as an indicator of diarrheal incidence in critically ill patients

Abstract: Recently, we noted that substantial numbers of critically ill patients admitted to a medical ICU developed diarrhea. We checked them for infectious, metabolic, and untoward medication effects, which were negative. We next considered a possible causal relation between reduced serum albumin and diarrhea. To document the frequency of diarrhea in this population, explore the relation between hypoalbuminemia and diarrhea, and make a preliminary assessment of a peptide-based, chemically defined diet in these catabolic patients, a study of consecutive medical ICU patients was begun. For each patient, we recorded the principal diagnosis, type of diet received, the frequency and volume of stool, and the serum albumin concentration at admission. When diarrhea developed, attention was paid to the serum albumin levels as well as the effects of various diets. Overall, 12 (34%) of 35 study patients developed diarrhea. No patient had a previous history of diarrhea, malabsorption, weight loss, or GI symptoms that may precede the onset of diarrhea. The stools from each patient with diarrhea were examined for enteric pathogens, ova and parasites, Clostridium difficile culture and cytotoxin assay, and qualitative stool fat, which were all negative. Every patient with a serum albumin level less than 2.6 g/dl developed diarrhea. No patient with a serum albumin level of 2.6 g/dl or greater developed diarrhea, regardless of the type of nutritional support received. Four of the 12 patients with hypoalbuminemia and diarrhea were placed on a peptide-based, chemically defined diet, after which their diarrhea resolved and their serum albumin concentrations increased.

Endobronchial instillation of epinephrine during cardiopulmonary resuscitation.

Abstract: We used a standard animal CPR model to study the effectiveness and hemodynamic response of 100 micrograms/kg epinephrine administered endobronchially and to compare the findings after conventional iv administration. Results showed that the endobronchial and iv epinephrine medication improved the survival rate by 100% compared to that of a control group receiving no medication. Although the hemodynamic conditions during cardiac compression were not significantly different after both routes of drug administration, endobronchial instillation produced a prolonged drug action during the first hour of restored spontaneous circulation. A more extensive use of this type of drug administration, especially in out-of-hospital resuscitation, is suggested.