Showing papers in "Critical Care Medicine in 1986"
TL;DR: The form and validation results of APACHE II, a severity of disease classification system, are presented, showing an increasing score was closely correlated with the subsequent risk of hospital death for 5815 intensive care admissions from 13 hospitals.
Abstract: This paper presents the form and validation results of APACHE II, a severity of disease classification system. APACHE II uses a point score based upon initial values of 12 routine physiologic measurements, age, and previous health status to provide a general measure of severity of disease. An increasing score (range 0 to 71) was closely correlated with the subsequent risk of hospital death for 5815 intensive care admissions from 13 hospitals. This relationship was also found for many common diseases.When APACHE II scores are combined with an accurate description of disease, they can prognostically stratify acutely ill patients and assist investigators comparing the success of new or differing forms of therapy. This scoring index can be used to evaluate the use of hospital resources and compare the efficacy of intensive care in different hospitals or over time.
5,266 citations
3,207 citations
TL;DR: A new stroke volume equation for thoracic electrical bioimpedance is proposed, which is modeled geometrically as a frustum (truncated cone), rather than a cylinder, and employs a percentage of overall body height in lieu of a measuredThoracic length.
Abstract: A new stroke volume equation for thoracic electrical bioimpedance is proposed. This empirically derived formula differs from previous equations in that: the thoracic volume conductor is modeled geometrically as a frustum (truncated cone), rather than a cylinder; the specific resistivity of blood, rho, is appropriately eliminated as an independent variable; the equation employs a percentage of overall body height in lieu of a measured thoracic length; and a new term, delta, is introduced to scale the parent equation for deviation from ideal body weight.
456 citations
TL;DR: MOSF is significantly associated with mortality in pediatric patients; however, it is not sufficiently discriminating to determine continuation or withdrawal of ICU support, and comparison with data from adult ICU patients indicates that the mortality and clinical course of MOSF in children is distinct from adults.
Abstract: The association of multiple organ system failure (MOSF) with mortality was investigated in 831 consecutive admissions to a pediatric ICU. The incidence of MOSF (at least two organ system failures, OSF) was 27%. Of the 62 nonsurvivors, 60 (97%) had MOSF. The mortality for patients with MOSF was 54%, compared to a mortality of 0.3% for patients without MOSF. Mortality increased directly with increasing number of OSF (p less than .0001). The mortality was 1% for one OSF, 11% for two OSF, 50% for three OSF, and 75% for four OSF. Comparison of these results with data from adult ICU patients indicates that the mortality and clinical course of MOSF in children is distinct from adults. MOSF is significantly associated with mortality in pediatric patients; however, it is not sufficiently discriminating to determine continuation or withdrawal of ICU support.
249 citations
TL;DR: The present study entails real-time, beat-to-beat cardiac output determinations using TEB and assessing its agreement via a digital computer against a reference standard, thermodilution.
Abstract: Thoracic electrical bioimpedance (TEB) is a noninvasive method for the estimation of left ventricular stroke volume (SV). Objections to TEB in the past have included systematic overestimation of SV and cardiac output in normals, poor correlation in absolute terms with standard cardiac output reference techniques, motion and ventilation artifacts which distorted recorded waveforms except when patients remained in apnea during measurements, and lack of a computer to yield rapid heat-to-beat quantitation of SV and cardiac output. The present study entails real-time, beat-to-beat cardiac output determinations using TEB and assessing its agreement via a digital computer against a reference standard, thermodilution. A correlation coefficient of 0.88 is reported with 85% of data points falling within 20% confidence limits on either side of the line of identity.
206 citations
TL;DR: Because severe cerebral edema and herniation after near-drowning is usually associated with irreversible brain damage, measures to control brain swelling such as hypothermia and barbiturates will be of little benefit.
Abstract: We retrospectively evaluated the clinical and pathologic effects of hypothermia and high-dose barbiturate therapy on hypoxic/ischemic cerebral injury after near-drowning in children. Of 40 near-drowned patients admitted to the ICU, 13 died, seven had permanent cerebral damage, and 20 survived. Twenty-four patients (group 1) were treated with a regime of hyperventilation, hypothermia, and high-dose phenobarbitone while intracranial pressure (ICP) was continuously monitored. Of ten who died in this group, three were diagnosed as having cerebral death shortly after admission; autopsy revealed severe cerebral edema with herniation. The remaining seven nonsurvivors had severe cerebral hypoxia without raised ICP and had the features of severe adult respiratory distress syndrome and hypoxic/ischemic damage to other organs. Six of these seven patients developed septicemia which was invariably associated with a profound neutropenia. Sixteen patients (group 2) were treated with a similar protocol but without hypothermia. Three of these patients died but only one developed septicemia. Neutropenia after resuscitation from near-drowning seemed to indicate a poor prognosis; the mean polymorphonuclear leukocyte count in nonsurvivors (1.9 +/- 0.5 X 10(9) cell/L) was significantly (p less than .01) lower than that in survivors (6.4 +/- 1.1 X 10(9) cell/L). Hypothermia was associated with a decreased number of circulating PMNs but did not increase the number of neurologically intact survivors. Similarly, although barbiturates may control ICP, their use did not improve outcome. Because severe cerebral edema and herniation after near-drowning is usually associated with irreversible brain damage, measures to control brain swelling such as hypothermia and barbiturates will be of little benefit.(ABSTRACT TRUNCATED AT 250 WORDS)
199 citations
TL;DR: The ability to breathe spontaneously through an endotracheal tube is a usual prerequisite before an intubated patient can have it removed and the tension-time index critical fatigue level of 0.15 was approached or exceeded.
Abstract: The ability to breathe spontaneously through an endotracheal tube is a usual prerequisite before an intubated patient can have it removed. Other researchers have measured air flow resistance through endotracheal tubes. In this study, we evaluated work of breathing in joules per min and tension-time
192 citations
TL;DR: Despite more training and experience, MD and RN performance was comparable to layperson performance, and data suggest that improving basic life-support skills could save more lives.
Abstract: To evaluate retention of CPR skills by medical residents (MDs), registered nurses (RNs), we tested single-rescuer CPR skills of 21 MDs, 17 RNs, and 21 laypersons using recording manikin and American Heart Association criteria. All study participants had been trained from 4 to 12 months before testing. No MD or RN and only one layperson performed each step correctly and in proper sequence. If calls for assistance were eliminated, one additional layperson, two MDs, and two RNs performed correctly. There were no significant differences between the MDs and RNs. MDs and RNs did better (p less than .01) in assessment compared to laypersons, but some individuals in each group initiated ventilations and compressions without assessing need. There was no difference in the ability to perform ventilations; all three groups did poorly. MDs and RNs performed compression skills better than laypersons (p less than .01), but all had difficulty with rate and depth of compressions. Moreover, only one-third of the general public demonstrated correct hand placement. Despite more training and experience, MD and RN performance was comparable to layperson performance. These data suggest that improving basic life-support skills could save more lives.
185 citations
TL;DR: The SPV and its δ down component correlated to the degree of hemorrhage as well as the CO and the pulmonary capillary wedge pressure, and significantly better than the central venous pressure and the mean systemic blood pressure.
Abstract: Systolic pressure variation (SPV) is defined as the difference between the maximum and minimum values of systolic blood pressure following a single positive pressure breath. An increase in the SPV is known to occur clinically during hypovolemia. This study aims to quantify SPV during graded hemorrhage in ventilated dogs, and to compare its reliability relative to other hemodynamic indicators of hypovolemia. Ten anesthetized dogs were mechanically ventilated with a fixed tidal volume. A continuously inflated vest was applied around the chest to maintain the ratio of lung to chest wall compliance similar to that of humans (0.83 ± 0.12). SPV was further divided into δ up and δ down components relative to apneic (5 s) systolic blood pressure. Dogs were bled 5, 10, 20, and 30% of their estimated blood volume. The measured parameters best correlated to the amount of bleeding were SPV (ra, = 0.993), δ down (ra, = 0.981), and cardiac output (ra, = 0.976). The SPV and its δ down component correlated to the degree of hemorrhage as well as the CO and the pulmonary capillary wedge pressure, and significantly better than the central venous pressure and the mean systemic blood pressure. Thus, SPV and its δ down component arc accurate indicators of hypovolemia in ventilated dogs subjected to hemorrhage.
162 citations
TL;DR: The data indicate satisfactory correlations between these two methods, which indicate that when the TEB waveform is satisfactory, the agreement between TEB and thermodilution is as good as the agreementBetween serial ther modilution methods.
Abstract: In order to evaluate a new thoracic electrical bioimpedance (TEB) system for measurement of stroke volume based on the Sramek-Bernstein equation, 391 paired values of cardiac output were measured simultaneously with the standard thermodilution method. These values were obtained from 16 patients selected for having the most severe illness during a 6-month period; the intent was to evaluate the bioimpedance method in the worst possible situations. The correlation coefficient (r) was 0.83, slope was 0.87, intercept was 1.53, and the mean difference between the two methods was 16.2 +/- 11.8 (SD)% in the total series. In 285 paired samples where satisfactory conditions were met, r was 0.90, slope was 0.98, intercept was 0.34, and the mean difference was 11.8 +/- 8.9%. The data indicate satisfactory correlations between these two methods. When the TEB waveform is satisfactory, the agreement between TEB and thermodilution is as good as the agreement between serial thermodilution methods. Difficulties may arise with dysrhythmias, tachycardia (heart rate greater than 150 beat/min), metal in the chest or chest wall, sepsis, hypertension, and extremely oily skin. Mechanical ventilation did not appear to be a problem.
161 citations
TL;DR: Mortality and neurologic morbidity were evaluated in children who were successfully resuscitated after being brought to an emergency room with continued apnea and pulselessness.
Abstract: Mortality and neurologic morbidity were evaluated in children who were successfully resuscitated after being brought to an emergency room with continued apnea and pulselessness. Of 34 patients studied from June 1981 through August 1984, 27 died during the initial hospitalization and seven (21%) surv
TL;DR: This study was designed to examine prospectively the incidence of perioperative complications associated with elective tracheostomy in critically ill patients and found no loss of airway in 81 procedures.
Abstract: This study was designed to examine prospectively the incidence of perioperative complications associated with elective tracheostomy in critically ill patients. An experienced surgeon and anesthesiologist participated in every tracheostomy procedure. In 81 procedures, there was no loss of airway control for greater than 20 sec, no airway obstruction, no blood loss exceeding 50 ml, and no aspiration. One patient (1.2%) had cardiovascular instability. During the next 48 h, two patients (2.4%) required wound packing to control hemorrhage but did not require blood transfusion and two patients (2.4%) had evidence of supraclavicular subcutaneous emphysema that was physiologically inconsequential. There was no perioperative mortality or major morbidity associated with the tracheostomy procedure. We conclude that, under controlled conditions, elective tracheostomy can be performed safely in critically ill patients.
TL;DR: The outcome of pediatric cardiac arrest is poor when arrest occurs in the hospital, and predictors of nonsurvival were duration of arrest greater than 15 min and the administration of more than one iv bolus of epinephrine.
Abstract: We retrospectively reviewed the results of 42 cardiopulmonary arrests occurring over 1 yr in the general ward of a pediatric hospital. These data were compared to those of a similar study done 10 yr previously in the same institution. Patients were divided into those having pure respiratory arrest and those who also had cardiac arrest. In the most recent series, overall 6-month survival was 17%; however, only 9% of the cardiac arrest patients survived. Ten years previously, the survival rate from cardiac arrest was 11%. In both series, pure respiratory arrest had a significantly better outcome than cardiopulmonary arrest, and predictors of nonsurvival were a duration of arrest greater than 15 min and the administration of more than one iv bolus of epinephrine. During the more recent series, sepsis and upper airway problems produced fewer arrests. There was one neurologically damaged survivor in each study period. Our study confirms that the outcome of pediatric cardiac arrest is poor when arrest occurs in the hospital.
Journal Article•
TL;DR: The data indicate that patients nasally intubated are at risk for development of paranasal sinusitis; this diagnosis should be suspected in sepsis of undetermined etiology.
Abstract: Paranasal sinusitis secondary to prolonged nasotracheal intubation represents an infrequently reported source of sepsis. Of 27 nasally intubated patients who developed paranasal sinusitis over a 1-yr period, 17 patients underwent emergency blind nasotracheal intubation post-trauma or shock (group 1) and the remaining ten were intubated electively under operating room or ICU conditions (group 2). Group 1 patients were younger (mean age 33 +/- 6 vs. 57 +/- 5 yr) than those in group 2; they also developed sinusitis more quickly after intubation (mean time 8 +/- 1 vs. 15 +/- 2 days). Diagnosis was confirmed via sinus x-rays (14 cases), computed tomography (five cases), indium scan (two cases), or clinical picture. Cultures were obtained in 14 cases. Staphylococci predominated in group 1, while nosocomial Gram-negative organisms predominated in group 2. Seven patients developed pulmonary infections and two developed systemic sepsis with an organism present on sinus culture. In all cases treatment was successful with antibiotics and tracheostomy or movement of the tube to the oral route. These data indicate that patients nasally intubated are at risk for development of paranasal sinusitis; this diagnosis should be suspected in sepsis of undetermined etiology.
TL;DR: Survival and life quality were related inversely to severity of illness and cost of treatment, and acute health on ICU admission and chronic health and age were better predictors of life quality.
Abstract: The high cost of treatment in an ICU is clearly recognized; the ultimate benefit of that care in prolonging meaningful life is not as well quantified. We evaluated 337 mixed medical-surgical ICU patients for severity of illness and intensity of therapy and assessed their survival and quality of life 16 to 20 months after discharge. Mortality was 36.9% for emergency surgical and medical patients and 13.9% for elective surgical patients. A total of 140 patients responded to follow-up; 62.2% of patients not retired or homemakers were working full-time. Quality of life was good using both subjective and objective standards. There were few significant differences between elective surgical and other patients. Survival and life quality were related inversely to severity of illness and cost of treatment. Acute health on ICU admission predicted survival well; chronic health and age were better predictors of life quality.
TL;DR: The role of interleukin 1 (IL 1) in 16 patients with sepsis and 16 normal controls was investigated in this article, where the authors used costimulation to assay in vitro IL 1 levels produced by adherent cells in the peripheral blood, and in vivo IL 1 in the serum.
Abstract: The role of interleukin 1 (IL 1) in 16 patients with sepsis and 16 normal controls was investigated. Thymocyte costimulation was used to assay in vitro IL 1 levels produced by adherent cells in the peripheral blood, and in vivo IL 1 levels in the serum. Adherent cells (i.e., monocytes) from nonsurviving septic patients produced significantly less IL 1 activity than cells from healthy controls or surviving patients, either spontaneously or by silica stimulation. In contrast, in vitro IL 2 production by T lymphocytes was not altered in septic patients. Serum IL 1 activity was determined using serum fractions from high-pressure liquid chromatographic gel filtration. Suppressor factors in healthy subjects as well as septic patients usually eluted at molecular weights above 50 kilodaltons, while IL 1-like activity was normally present between 35 and 1 kilodaltons. Sera of nonsurviving septic patients contained significantly less IL 1 compared to that of controls or surviving patients. Thus, decreased serum IL 1 levels and diminished monocyte production of IL 1 appear to be negative prognostic indicators, possibly reflecting a breakdown of mononuclear phagocytes.
TL;DR: It is concluded that CAVH eliminates cardiopulmonary toxic substances partly responsible for shock and may be useful in postoperative cardiac surgery patients with respiratory and hemodynamic failure.
Abstract: Hemodynamic and oxygen measurements were obtained before and during 24 h of continuous arteriovenous hemofiltration (CAVH) in 36 postoperative cardiac surgery patients with severe acute pulmonary failure. During the first 6 h, the low mean arterial pressure averaged only 50 +/- 7 mm Hg; PaO2 was 90 torr on an inspired oxygen fraction of 0.86 +/- 0.03; and lactic acid was 10.5 +/- 6 mmol/L. Of the 34 patients recovering from shock within 12 h, only 24 (67%) were hospital survivors. Cardiac index, oxygen availability index, oxygen consumption, and PaO2 increased during CAVH. This treatment decreased serum levels of the myocardial depressant factor, thus allowing catecholamine support to be reduced. We conclude that CAVH eliminates cardiopulmonary toxic substances partly responsible for shock. Our patients' improved hemodynamic and respiratory function suggests that CAVH may be useful in postoperative cardiac surgery patients with respiratory and hemodynamic failure.
TL;DR: Ketamine should only be used for asthmatics whose respiratory failure does not respond to conventional management and mechanical ventilation, and except for increased secretions during the infusion, patients showed no immediate or long-term sequelae from ketamine therapy.
Abstract: We treated two pediatric patients suffering respiratory failure associated with status asthmaticus. Neither patient responded to maximal bronchodilatory therapy and mechanical ventilation; however, continuous infusion of ketamine (1.0 to 2.5 mg/kg X h) immediately improved airway obstruction. Ketamine appears to increase catecholamine levels and directly relax bronchial smooth muscle. Except for increased secretions during the infusion, our patients showed no immediate or long-term sequelae from ketamine therapy. However, ketamine should only be used for asthmatics whose respiratory failure does not respond to conventional management and mechanical ventilation.
TL;DR: During this period, systolic BP and heart rate significantly increased only in patients recovering from major general/vascular surgery or carotid endarterectomy, since the other surgical patients were anesthetized with narcotic anesthesia, and the control group did not receive any anesthesia.
Abstract: We examined cardiovascular changes in 37 patients transported to an ICU after major general or vascular surgery (n = 14), open heart surgery (n = 13), or carotid endarterectomy (n = 10). Cardiovascular variables were also measured in a control group of 11 patients transported from an ICU for diagnostic or therapeutic procedures. All patients were followed for 30 min before transport until approximately 30 min after they arrived at their destinations. During this period, systolic BP and heart rate significantly increased only in patients recovering from major general/vascular surgery or carotid endarterectomy. These changes were apparently related to acute emergence from inhalational anesthesia (isoflurane plus nitrous oxide), since the other surgical patients were anesthetized with narcotic anesthesia, and the control group did not receive any anesthesia.
TL;DR: Survivors had higher hemoglobin, lower systemic vascular resistance, and higher oxygen delivery than nonsurvivors, and Septic complications increased the risk of multisystem organ failure and death.
Abstract: Information on factors that influence survival of older patients after traumatic injury is limited. To determine differences between survivors and nonsurvivors, 39 patients over age 60 were studied. Pre-existing disease, type of trauma, and shock did not influence survival. The trauma score, injury severity score, and acute physiology score did not predict survival. Survivors had higher hemoglobin, lower systemic vascular resistance, and higher oxygen delivery than nonsurvivors. Septic complications increased the risk of multisystem organ failure and death.
TL;DR: Cardiac output was measured 120 times in 27 critically ill patients using the thermodilution and transthoracic electrical impedance methods and the mean distance between the inner electrodes and a p-value of 150 ohmċcm gave the best agreement.
Abstract: Cardiac output was measured 120 times in 27 critically ill patients using the thermodilution and transthoracic electrical impedance methods. Both the minimum and mean values for the distance between the inner electrodes, and a variety of values for the resistivity of blood (rho) were substituted in the Kubicek's empiric formula for calculating cardiac output by transthoracic electrical impedance. Using the mean distance between the inner electrodes and a rho-value of 150 ohm X cm gave the best agreement between the methods (mean difference 0.17 +/- 2.4 L/min). Ventilation alone or with positive end-expiratory pressure did not significantly affect the bias of the estimate, but both affected its precision when compared with measurements in spontaneously breathing patients (SD of mean difference 2.4 and 3.2 L/min, respectively, vs. 1.5 L/min). The pulmonary artery wedge pressure was significantly higher in patients with an abnormal diastolic impedance waveform (zero-wave), but there was no relationship between wedge pressure and base impedance per unit length between the measuring electrodes.
TL;DR: The ICU records of 31 patients with the acquired immunodeficiency syndrome were reviewed; 21 of 23 respiratory failure patients died, compared to three (38%) of the eight without respiratory failure, and all seven ICU survivors lived to hospital discharge.
Abstract: The ICU records of 31 patients with the acquired immunodeficiency syndrome were reviewed. Of 23 (74%) patients admitted for respiratory failure requiring intubation and mechanical ventilation, 20 (87%) patients had Pneumocystis carinii and/or cytomegalovirus pneumonia. Of the eight patients admitted without respiratory failure, five (63%) were monitored after brain biopsy. Respiratory failure patients remained in the ICU for 10 +/- 1 days, compared to 5 +/- 1 days for those without respiratory failure (p less than .05). Overall mortality was 24 patients (77%); 21 (91%) of 23 respiratory failure patients died, compared to three (38%) of the eight without respiratory failure (p less than .01). All seven ICU survivors lived to hospital discharge.
TL;DR: There probably is a relatively low incidence of ARDS among hospital patients admitted with high-risk diagnoses, and mortality was also high in patients with multisystem organ failure or with ARDS and disseminated intravascular coagulation.
Abstract: We examined the incidence and mortality of adult respiratory distress syndrome (ARDS) in patients receiving emergency medical care at a large metropolitan medical center. The patients were classified into eight high-risk categories and monitored prospectively until discharge or death. Over a period
TL;DR: Observed changes in near-infrared absorption in the tissues during serial intravascular injections of indocyanine green dye indicate that different cytochrome responses to hypoxia and oligemia in muscle vs. brain tissue are attributable to different regional circulatory adjustments.
Abstract: During continuous near-infrared optical monitoring of brain cortex and hindlimb skeletal muscles, anesthetized, ventilated cats were exposed either to progressive alveolar hypoxia, or to acute hemorrhage followed in some cases by resuscitation. Hypoxia decreased cytochrome a,a3 oxidation state in mu
TL;DR: This is the first clinical report on the use of isoflurane anesthesia to treat severe asthma, and despite prolonged administration, there were no significant side-effects.
Abstract: We report a case of status asthmaticus that was unresponsive to the usual agents. The use of an inhalational anesthetic agent allowed us to ventilate the patient with lower inspiratory pressures; however, lasting improvement did not occur until she mobilized large quantities of secretions. To our knowledge, this is the first clinical report on the use of isoflurane anesthesia to treat severe asthma. Despite prolonged administration, there were no significant side-effects. This case demonstrates both the benefits and limitations of such therapy.
TL;DR: It is demonstrated that, with appropriate hemodynamic stabilization and monitoring, severely ill patients can be transported safely from community hospitals to Stanford Medical Center.
Abstract: Interhospital transport can be hazardous because of rapid changes in a patient's physiologic status and the use of monitoring systems A retrospective study evaluated the first 204 critically ill adult patients transported from community hospitals to Stanford Medical Center by a special transport team To relate the risk of transport to severity of illness, a retrospective scoring system was devised Sixty-one percent (n = 125) of the patients were at high risk for transport The patients were stabilized at the referring hospital, and invasive monitoring was used as mandated by the patient's condition The average transport distance was 133 km, and the average duration of transport was 438 h One hundred and five patients (515%) were transported by air, and the remaining patients were transported by surface ambulance All patients survived the transport, and 716% were eventually discharged from the hospital Hospital mortality correlated with the risk-scoring system (p less than 01) and increased five-fold as severity of illness increased This study demonstrates that, with appropriate hemodynamic stabilization and monitoring, severely ill patients can be transported safely
TL;DR: The study suggests that PAC placement carries certain risks and complications which should be weighed against the advantages of a PAC in each patient.
Abstract: Of 142 critically ill patients undergoing pulmonary artery catheter (PAC) insertion, 1.4% suffered pneumothorax and 7.7% experienced arterial puncture during central venous access. Catheterization was successful in all cases; however, 8.4% of patients required special maneuvers for pulmonary artery cannulation. The 52.3% incidence of cardiac arrhythmias during PAC insertion was primarily due to ventricular arrhythmia (VA), which was more common among patients with complicated myocardial infarction (p less than .01) and less common in patients with sepsis (p less than .05). The development of VA was significantly related to the duration of PAC insertion. Our study suggests that PAC placement carries certain risks and complications which should be weighed against the advantages of a PAC in each patient.
TL;DR: The results support the assumption that early aggressive shock treatment with dextran 70, followed by continueddextran administration in the post-trauma period might prevent complications such as ARDS, and patients should continue on a fluid program containing dextan 70 to counteract unrecognized, hypovolemia.
Abstract: During a 3-yr period, 31 adult victims of severe traumatic shock were enrolled in a prospective randomized investigation of the relative effectiveness of dextran 70 vs. Ringer's acetate to treat shock and protect against trauma-induced adult respiratory distress syndrome (ARDS). Fourteen patients were given dextran 70 and Ringer's acetate to compensate for interstitial fluid loss, and whole blood as required; the remaining 17 patients received three to four times the total fluid volume of Ringer's acetate given in the former group, and whole blood as required. Hemodynamics improved significantly more rapidly in the dextran group. In the 7 to 8-day post-trauma period, no patient in the dextran group developed ARDS, compared to five cases of ARDS in the Ringer's acetate group. Also, the cardiac index of dextran patients was significantly higher, and patients challenged with 0.5 L of dextran 70 showed a significantly higher increase in cardiac index than those challenged with 2 L of Ringer's acetate. It is concluded that in the severely traumatized patient, a fluid program based on dextran 70 is superior to Ringer's acetate alone. Furthermore, patients should continue on a fluid program containing dextran 70 to counteract unrecognized hypovolemia. Our results support the assumption that early aggressive shock treatment with dextran 70, followed by continued dextran administration in the post-trauma period might prevent complications such as ARDS.
TL;DR: This measurement was simple, reproducible, and provided a more precise capillary filtration pressure than Pw, which should be clinically useful in monitoring patients with pulmonary hypertension and adult respiratory distress syndrome, especially those with pulmonary artery catheters.
Abstract: Pulmonary artery catheters are frequently used to measure pulmonary vascular pressures, particularly the pulmonary wedge pressure (Pw), which reflects pulmonary venous and ideally left atrial pressures. However, the pulmonary capillary pressure (Pc) is the major force in the formation of pulmonary edema. Unfortunately, Pw has been interpreted as being identical to Pc. In this study we used 7-Fr pulmonary artery catheters to measure effective Pc in closed-chest animals and patients. The decreasing pressure profile after pulmonary artery occlusion was separated into fast and slow components, with the inflection point between them representing Pc. Pc was also estimated by mathematically analyzing the curves in terms of a precapillary resistance, a large pulmonary capillary capacitor, and a postcapillary resistance. In dogs, Pc was determined after pulmonary vascular resistance had been increased by infusing serotonin and histamine. While Pw remained unchanged, serotonin increased pulmonary artery pressure (Ppa) 52% and Pc 16%, whereas histamine increased Ppa only 25%, but increased Pc by 35%. This is consistent with studies showing that serotonin primarily elevates precapillary resistance, and histamine increases postcapillary resistance. In thoracic surgery patients, Pc was not consistently related to Pw. This measurement was simple, reproducible, and provided a more precise capillary filtration pressure than Pw. It should be clinically useful in monitoring patients with pulmonary hypertension and adult respiratory distress syndrome, especially those with pulmonary artery catheters.
TL;DR: HFOV is found to be effective in the treatment of PIE and hypothesieze that interstitial airleak is decreased during HFOV because adequate ventilation is provided at lower peak distal airway pressures.
Abstract: Twenty-seven low birth weight infants who developed pulmonary interstitial emphysema (PIE) and respiratory failure while on conventional ventilation were treated with high-frequency oscillatory ventilation (HFOV). The mean birth weight was 1.2 kg (range 0.55 to 2) with gestational age of 28 wk (range 25 to 34). Ten patients died, six of whom had documented sepsis with shock and were therefore excluded from analysis. All patients showed initial improvement on HFOV. Surviving patients showed continued improvement in oxygenation and ventilation at increasingly lower fraction of inspired oxygen and proximal airway pressure with resolution of PIE, while nonsurvivors progressively developed chronic respiratory insufficiency with continued PIE from which recovery was not possible. Overall survival in nonseptic patients was 80% (16 of 20). We found HFOV to be effective in the treatment of PIE and hypothesize that interstitial airleak is decreased during HFOV because adequate ventilation is provided at lower peak distal airway pressures.