Thermodilution evaluation of right ventricular performance.
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Humans↗
Biomedical subjects
D J Dries
Publications and source records attributed to D J Dries.
Burn-induced nitric oxide release in humans.
Nitric oxide (NO) generation in a series of 20 burn patients was studied with a novel anion exchange high-performance liquid chromatographic method for the simultaneous determination of nitrite (NO2-) and nitrate (NO3-), the stable metabolic endproducts of NO. The NO values within our survivor group (n = 17) were significantly altered at days 1, 6, and 12 postburn in contrast to controls (n = 23) (p < or = 0.03). NO2- values were significantly depressed in both plasma and urine, whereas NO3- values were significantly elevated in contrast to control values (p < or = 0.03). The ratio of NO2-:NO3- was significantly lower for burn patients versus controls in both plasma and urine (p < 0.01). The NO generation seemed in part to be dependent on the percentage of total body surface area burn, most dramatically elevated in patients with burns of 10 to 40% total body surface area. In subjects who did not survive beyond 36 hours postinjury because of irreversible shock (n = 3), the production of NO was significantly depressed in contrast to survivors and controls (p < 0.0001). However, the NO2-:NO3- ratio (0.001) was relatively unchanged, with reflection of a global depression in NO formation with no change in the individual component release. Burn injury resulted in an increased release/production of NO that in the first postburn week is maximally elevated immediately postinjury. NO release, although decreased at day 6 relative to the day 1 values, remained elevated into the second week postinjury when there was evidence for a further increase in NO production. The enhanced NO3- formation may well result from NO reacting with oxygen-free radicals counteracting superoxide anion-induced destruction of tissue, thereby potentially functioning as a protectant molecule.
Anion Exchange Resins↗
Permissive hypercapnia.
Traditional practice of mechanical ventilation includes tactics to reduce lung injury, such as avoidance of excessive airway pressure, patient distress, and tidal volume. Gas exchange objectives have received priority, however, and a degree of lung injury has been accepted as inevitable. The current trend toward increasing use of permissive hypercapnia is based on the recognition that lung injury induced by mechanical ventilation may be reduced by compensated hypercapnia with few serious adverse effects and contraindications.
Acidosis, Respiratory↗
Effect of interferon gamma on infection-related death in patients with severe injuries. A randomized, double-blind, placebo-controlled trial.
OBJECTIVE: To assess the efficacy of interferon gamma in reducing infection and death in patients sustaining severe injury. DESIGN: Multicenter, randomized, double-blind, placebo-controlled trial with observation for 60 days and until discharge for patients with major infection on day 60. SETTING: Nine university-affiliated level 1 trauma centers. PATIENTS: Four hundred sixteen patients with severe injuries, assessed by Injury Severity Score and degree of contamination. INTERVENTION: Recombinant human interferon gamma, 100 micrograms, was administered subcutaneously once daily for 21 days (or until patient discharge if prior to 21 days) as an adjunct to standard antibiotic and supportive therapy. MAIN OUTCOME MEASURES: Incidence of major infection, death related to infection, and death. RESULTS: Infection rates were similar in both treatment groups; however, patients treated with interferon gamma experienced fewer deaths related to infection (seven [3%] vs 18 [9%]; P = .008) and fewer overall deaths (21 [10%] vs 30 [14%]; P = .17). While 12 early deaths (days 1 through 7) occurred in each treatment group, late death occurred in 18 placebo-treated patients and nine in interferon gamma-treated patients. The results were dominated by findings at one center, which had the highest enrollment and higher infection and death rates. Statistical analysis did not eliminate the possibility of an unidentified imbalance between arms as an explanation for the results. CONCLUSION: Further evaluation is required to determine the validity of the observed reduction in infection-related deaths in patients treated with interferon gamma.
Adolescent↗
Systemic administration of interferon-gamma impairs wound healing.
Interferon-gamma (IFN-gamma), a cytokine that has been shown to upregulate macrophage function, has recently been demonstrated to improve outcome when exogenously administered in several animal models of injury. Because the macrophage is also important in the events that govern wound healing, we evaluated the effects of IFN-gamma upon wound healing in a murine model. IFN-gamma was administered in doses of 937.5-22,500 u synchronous with the creation of a left paraspinous wound and then daily. At Day 10, wounds were harvested, evaluated for wound disruption strength (WDS), and subjected to morphometric analysis. Wounds were also subjected to 36-hr formalin fixation to maximally cross-link collagen fibrils and retested for WDS. We found that IFN-gamma impaired wound healing at all doses relative to control, and WDS was impaired in a dose-dependent fashion. Our highest dose of IFN-gamma (22,500 u) produced a WDS only 65% of the control. Morphometric studies demonstrated less collagen deposition and a lower degree of neovascularity in IFN-gamma-treated animals. In addition, formalin fixation studies suggested that IFN-gamma may impair collagen cross-linking. The potential benefits of IFN-gamma in the multiply injured patient must be weighed against the possibility that IFN-gamma might deleteriously effect events fundamental to wound healing.
Animals↗
Interferon-gamma increases mortality following cecal ligation and puncture.
Interferon-gamma (IFN-gamma) has been demonstrated to improve outcome following localized infection and hemorrhagic shock in experimental studies. We sought to determine the effects of IFN-gamma in a clinically relevant murine model of intra-abdominal polymicrobial sepsis. Fifty male BDF1 mice, each weighing 23-28 g, underwent cecal ligation and puncture (CLP) followed by administration of subcutaneous injections of IFN-gamma 100-22,500 U or vehicle control immediately post-CLP and then daily. In a second set of experiments, 60 mice underwent daily injections of vehicle control or 100 U IFN-gamma 24, 48, or 72 hours prior to CLP. Interferon-gamma administered following CLP led to increased mortality and earlier deaths in a dose-dependent fashion (p < 0.05). Interferon-gamma given 24, 48, or 72 hours prior to CLP resulted in no demonstrable benefit when compared with animals that did not receive IFN-gamma (p = 0.14, p = 0.94, and p = 0.97, respectively). While IFN-gamma has been reported to be of value in selected clinical situations by improving resistance to infection, it may not be capable of conferring protection following surgery or trauma with intra-abdominal sepsis, and in fact may be detrimental.
Animals↗
Urine hydrogen peroxide during adult respiratory distress syndrome in patients with and without sepsis.
BACKGROUND: The lung injury in adult respiratory distress syndrome (ARDS) has been associated with increased expiratory hydrogen peroxide (H2O2) concentrations. Furthermore, patients with sepsis and ARDS are reported to have greater serum scavenging of H2O2 than patients with ARDS only. We hypothesized that the systemic presence of H2O2 would be detectable in the urine of these two groups of patients and that, in the case of ARDS sepsis, the relative contribution of each disease to the production this analyte would be discernible. Accordingly, we used an in vitro radioisotope assay to follow the weekly course of urine H2O2 levels in ARDS patients with and without sepsis, and in samples from control non-ARDS patients with sepsis with indwelling urinary catheters and in samples provided by healthy volunteers. METHODS: Thirty patients with ARDS were included in the study: 23 had sepsis and 7 were sepsis free. An indwelling catheter was used to collect urine from each patient over a 24-h period, first within 48 h of ICU admission and then every seventh day over the course of their illness. Urine H2O2 was measured by competitive decarboxylation of 1-14C-alpha-ketoglutaric acid by H2O2. Urine samples were provided by 20 healthy volunteers while, in 10 non-ARDS patients with sepsis, urine was collected over one 24-h period following a 5-day minimum with an indwelling urinary catheter. RESULTS: Urine H2O2 concentration in healthy control subjects (88 +/- 4 mumol/L) and non-ARDS patients with urinary catheters (96 +/- 5 mumol/L) was not significantly different. During the first 48 h in the ICU, urine H2O2 in patients with ARDS only (295 +/- 29 mumol/L) was significantly lower (p < 0.05) than patients with ARDS and sepsis (380 +/- 13 mumol/L); however, the lung injury scores of these two groups did not differ. Furthermore, within the first 48 h, the urine H2O2 of the patients with ARDS and sepsis who did not survive (427 +/- 19 mumol/L; n = 7) was significantly higher than that in patients who survived sepsis (352 +/- 14 mumol/L; n = 15). Thereafter, the lung injury scores and urine H2O2 levels of the nonsurvivor ARDS-sepsis group remained significantly higher compared with the other two groups. At lung injury scores of 3 and 2, regardless of days in ICU, the patients with ARDS only had significantly lower urine H2O2 (266 +/- 30 mumol/L and 167 +/- 24 mumol/L, respectively) compared with the survivor ARDS-sepsis group (376 +/- 19 mumol/L and 250 +/- mumol/L). When the patients with ARDS (both ARDS only and with sepsis) recovered, their urine H2O2 concentration did not differ from the control groups (healthy donors and patients without ARDS). CONCLUSION: Lung injury scores did not differentiate patients with ARDS and sepsis from patients with ARDS only during the first 10 days in the ICU; however, urine H2O2 levels were significantly greater in the patients with ARDS and sepsis. Moreover, despite no initial difference in lung injury, patients who did not survive ARDS and sepsis had consistently greater urine H2O2 concentration than patients who survived sepsis. The urine H2O2 level in the ARDS-only group was about 70 percent of the level in the survivor ARDS and sepsis group, suggesting that ARDS alone is the major contributor to the H2O2 oxidant processes during combined ARDS and sepsis. Furthermore, these studies demonstrate that urine H2O2 may be a useful analyte to differentiate the severity of oxidant processes in patients with ARDS and sepsis albeit the prognosis appears to be survival or nonsurvival.
Adolescent↗
The role of diagnostic laparoscopy in the management of trauma patients: a preliminary assessment.
This study evaluated the role and advantages of diagnostic laparoscopy (DL) compared with diagnostic peritoneal lavage (DPL) in 75 trauma patients who were prospectively studied with DL followed by DPL. Of these, 59 patients had blunt injuries and 16 stab wounds. Seventy patients (93%) had the procedures performed in the emergency department (ED); 41 (59%) of these were awake and under local anesthesia. Forty-two patients had negative DPL and DL results with no subsequent sequelae. Twenty-three patients had negative DPL results and abnormal DL results. Of these, 20 were managed nonsurgically, and three (DPL < 10,000 RBC) underwent surgery based solely on DL findings of diaphragmatic lacerations from stab wounds. These were repaired. All 23 had an uneventful course. Three patients had positive DPL and insignificant DL findings. Laparotomy and DL findings correlated. A splenectomy for iatrogenic injury unrelated to DL and two nontherapeutic laparotomies were performed. Seven patients demonstrated both positive DPL and significant DL findings, and all had therapeutic laparotomies. Management based on DL rather than DPL would potentially have improved care in 8% of cases (6 of 75). Reliance on DL improved care in 19% (3 of 16) of patients with stab wounds and possibly could have in 3% (2 of 59) of those with blunt injuries. Management using DL would have potentially improved care in 30% (3 of 10) of patients with positive DPL findings and 5% (3 of 65) with negative DPL findings. Diagnostic laparoscopy can be performed safely in stable patients under local anesthesia in the ED. It offers no advantage over DPL as a primary assessment tool in blunt trauma. It does have advantages in the management of stab wounds. Diagnostic laparoscopy has a role in redefining DPL criteria for laparotomy and, in selected patients, as an adjunct to DPL, allowing further diagnosis and potentially the treatment of injuries without laparotomy.
Abdominal Injuries↗
Aggressive hydration during continuous positive-pressure ventilation restores atrial transmural pressure, plasma atrial natriuretic peptide concentrations, and renal function.
BACKGROUND AND METHODS: The correlations between continuous positive-pressure ventilation-induced antidiuresis/antinatriuresis, atrial transmural pressure, and atrial natriuretic peptide concentrations have not been clarified. The purpose of the present study was to use aggressive hydration to restore atrial transmural pressure during continuous positive-pressure ventilation and to test for correlations of atrial transmural pressure, atrial natriuretic peptide concentration, diuresis, and natriuresis during this intervention. An intrapleural catheter was used to measure atrial transmural pressure in three ways: a) right atrial pressure minus intrapleural pressure, b) left ventricular end-diastolic pressure minus intrapleural pressure, and c) pulmonary artery occlusion pressure minus intrapleural pressure. Hemodynamic, atrial natriuretic peptide concentrations, and renal measurements were made in 12 anesthetized closed-chest dogs during baseline (intermittent positive-pressure ventilation), during continuous positive-pressure ventilation), during continuous positive-pressure ventilation with 10 cm H2O end-expiratory pressure, and during continuous positive-pressure ventilation plus aggressive hydration (approximately 60 mL/kg lactated Ringer's solution). Pearson's correlation matrix was used to generate all possible correlation coefficients between the three atrial transmural pressures, atrial natriuretic peptide concentrations, urine output, and urine sodium excretion. RESULTS: Application of continuous positive-pressure ventilation resulted in a 60% decrease in right atrial transmural pressure (p less than .05), a 51% decrease in left ventricular end-diastolic transmural pressure (p less than .05), and a 26% decrease in pulmonary artery occlusion transmural pressure (p less than .05) from baseline. Plasma atrial natriuretic peptide concentration decreased from 80 +/- 12 (SEM) pg/mL at baseline to 49 +/- 8 pg/mL during continuous positive-pressure ventilation (p less than .05). Both urine output and sodium excretion decreased by 81% (p less than .05). After aggressive hydration with lactated Ringer's solution during continuous positive-pressure ventilation, to restore atrial transmural pressure to baseline, plasma atrial natriuretic peptide concentration returned to baseline values (81 +/- 12 pg/mL) as did urine output and sodium excretion. Correlation indices (r2 values) between transmural pressure, atrial natriuretic peptide concentration, urine output, and sodium excretion ranged from .835 to .994. Multivariate analysis of covariance demonstrated significant (p less than .05) temporal dependence between the three transmural pressures, atrial natriuretic peptide concentration, urine output, and sodium excretion. CONCLUSIONS: The results demonstrate that aggressive hydration during continuous positive-pressure ventilation will restore diuresis and natriuresis and that this response correlates significantly with atrial transmural filling pressure and plasma atrial natriuretic peptide concentration.
Animals↗
Myocardial metabolism and adaptation during extreme hemodilution in humans after coronary revascularization.
OBJECTIVE: This study was designed to evaluate the oxygen transport adjustments and myocardial metabolic adaptation that occurs with different levels of hemodilution during normothermia after cardiopulmonary bypass. DESIGN: Prospective, nonrandomized study. SETTING: Operating room in a university hospital. PATIENTS: Eight patients with ejection fractions (> 40%) undergoing elective coronary artery bypass grafting. METHODS: Before the institution of cardiopulmonary bypass, blood was withdrawn from patients to a target hematocrit of 15%. After coronary artery bypass grafting, a catheter was inserted directly into the coronary sinus. After the patients were rewarmed to 37 degrees C, they were weaned from cardiopulmonary bypass. Hemodynamic indices were measured, as well as measurements of myocardial oxygen consumption (VO2) and myocardial metabolism (lactate extraction and coronary sinus hypoxanthine). Measurements were made at three different hematocrit values: 15%, 20%, and 25%. Hematocrit was increased by autologous blood transfusion. MEASUREMENTS AND MAIN RESULTS: The three levels of hemodilution (hematocrit: 17.4 +/- 3.4%; 23.0 +/- 3.7%; 27.8 +/- 4.8%) were significantly different from baseline (hematocrit 37 +/- 2.6%; p < .05). Oxygen delivery, which increased with autologous transfusion, exceeded 350 mL/min/m2 at each level of dilution. The myocardial VO2 increased significantly after autologous transfusion compared with the most dilute condition (7.0 +/- 3.7 mL/min at hematocrit 17.4% vs. 11.2 +/- 4.8 mL/min at hematocrit 23.0% and 12.4 +/- 4.0 mL/min at hematocrit 27.8%). This transfusion-induced increase was also true of myocardial oxygen extraction. Lactate extraction and hypoxanthine release were normal and unchanged at each level of hemodilution. Systemic oxygen extraction ratio increased with hemodilution and decreased with autologous transfusion. CONCLUSIONS: Hemodilution to a hematocrit of approximately 15% is tolerated in anesthetized humans after coronary artery bypass surgery. There was no evidence of myocardial ischemia, as demonstrated by absence of S-T depression on the electrocardiogram, lactate extraction, or hypoxanthine release. In selected patients, postoperative transfusion may be based on systemic physiologic end-points, such as oxygen extraction ratio, rather than set hematocrit values.
Blood Transfusion, Autologous↗
Predictors of blinding or serious eye injury in blunt trauma.
Multivariate analysis was used to identify factors predicting injury and visual outcome in 94 blunt trauma patients evaluated for eye injuries among 6700 admissions to a level I trauma center over a 29-month period. Patients with penetrating eye injuries were excluded from this review. Eye injury was detected in 93% or 87 of the patients evaluated. Seven percent of eye injuries resulted in blindness, 22% were serious (visual acuity between 20/40 and 20/200 or eye injury requiring surgery), and 71% were temporary (final visual acuity of 20/40 or better). The presence of an afferent pupillary defect or a nonreactive pupil was the most important factor in predicting the severity of eye injury (p = 0.0023), followed by facial fractures (p = 0.0084), and no eye opening or eye opening to pain within the Glasgow Coma Scale (p = 0.02). Eye injury is an infrequent complication of blunt trauma. Appropriate consultation for evaluation of this problem can be obtained based on findings from the initial history and screening physical examination.
Adolescent↗
Atrial natriuretic peptide may not play a role in diuresis and natriuresis after cardiac operations.
Human atria through release of atrial natriuretic peptide play an important role in extracellular fluid homeostasis. This study investigates the perioperative role of atrial natriuretic peptide, renin, angiotensin, aldosterone, and vasopressin in patient response to cardiopulmonary bypass after coronary artery bypass operations. Serum levels of these hormones were measured, along with hemodynamic profiles, urine output, and urine electrolytes, before induction of anesthesia, after discontinuation of cardiopulmonary bypass, 1 hour postoperatively, and 3 hours postoperatively. Serum levels of atrial natriuretic peptide were found to be significantly elevated immediately after discontinuation of cardiopulmonary bypass. These elevations did not correspond temporally to elevated central venous pressure or tachycardia. Significant natriuresis and diuresis were observed during the first postoperative hour. This diuresis failed to correspond temporally with alterations noted in serum levels of atrial natriuretic peptide, renin, angiotensin, aldosterone, and vasopressin. The mechanism responsible for the increases in serum atrial natriuretic peptide and the postoperative natriuresis and diuresis after cardiopulmonary bypass remain unknown.
Aged↗
Introduction of pulse oximetry in the air medical setting.
The importance of adequate oxygenation in critically ill patients is widely recognized. Pulse oximetry (PO) is a non-invasive, rapid technique of arterial hemoglobin oxygen saturation (SaO2) measurement. This report is a review of our experience using the PO during air medical transport. A chart review was conducted on patients who used air medical transport between October 1988 and March 1989. Types of patients included trauma and ICU patients who were transported from either accident scenes or outlying hospitals. SaO2 and vital sign (VS) measurements were obtained pre and postflight, and inflight interventions were documented. Four groups of patients were identified: Group 1: PO used, inflight intervention employed; Group II: PO used, no inflight intervention employed; Group III: no PO used, inflight intervention employed; Group IV: no PO used, no inflight intervention employed. A dependent, paired-t-test was used to compare pre and postflight SaO2 and VS measurements. The mean difference between pre and postflight measurements of SaO2, systolic blood pressure, and pulse rate were calculated within each group. Then, an ANOVA with post-hoc Newman-Keuls Test compared the means between the four groups. Of the 137 patients reviewed, 82 used PO and 55 patients did not due to technical or anatomic problems. Of the 82 patients who used PO, 19 received an inflight intervention.(ABSTRACT TRUNCATED AT 250 WORDS)
Aircraft↗
Adequate resuscitation of burn patients may not be measured by urine output and vital signs.
OBJECTIVE: To compare vital sign and urine output monitoring of seriously burned patients with invasive monitoring during early resuscitation. DESIGN: Retrospective review. SETTING: A university hospital burn unit. PATIENTS: Fourteen seriously burned patients who had pulmonary arterial monitoring. Monitoring data were compared at baseline and after fluid challenges. RESULTS: There was no correlation between invasively derived physiologic variables and vital signs and urine output. Vital signs and urine output changed little after fluid challenge, while variables from invasive monitoring demonstrated significant change. In half of the patients, oxygen consumption increased after fluid challenge; vital signs and urine output did not distinguish these patients. CONCLUSIONS: The use of urinary output and vital signs to guide initial burn resuscitation may lead to suboptimal resuscitation. Invasive cardiorespiratory monitoring may be necessary to optimize resuscitation of seriously burned patients.
Adolescent↗
Transoral crossbow injury to the cervical spine: an unusual case of penetrating cervical spine injury.
The complexity of missile injuries to the cervical spine has increased as the technology that causes these injuries has become more sophisticated. Management requires adaptation of conventional neurosurgical approaches to the cervical spine in an effort to limit neurological deficit and establish stability. We report an unusual case of a 19-year-old man who suffered transoral penetration of the cervical spine by an arrow released by a crossbow at close range.
Adult↗
Pressure support. Changes in ventilatory pattern and components of the work of breathing.
To evaluate the interaction between patient and ventilator during widely varying levels of pressure support (PS) ventilation, we studied 33 patients who had undergone aortocoronary bypass. All patients were without preoperative evidence of lung disease and had left ventricular ejection fractions greater than 45 percent. We assessed both changes in ventilatory pattern and the use of an extension of the Campbell technique to determine the components of the mechanical work of breathing (WOB). Patients were placed on 0, 10, 20, and 30 cm H2O of PS. We found that increasing the pressure support level (PSL) did not change minute ventilation, PCO2, or pH despite large changes in both rate and depth of breathing. The inspiratory time fraction was consistently and progressively reduced as PS increased. Although mean inspiratory flow (MIF) increased by 75 +/- 9 (SE) percent as the PSL increased to 30 cm H2O, mean airway pressure rose only 3.5 +/- 0.1 cm H2O. Observed changes in the resistive and elastic components of WOB at PSL greater than 0 were consistent with values predicted from baseline observations and changes in VT and MIF demonstrating that the Campbell technique of separating resistive and elastic components of the patient's WOB during unassisted ventilation can be extended to the analysis of WOB during mechanical ventilation. We were surprised to observe that although inspiratory WOB fell 67 +/- 13 percent as the PSL increased to 30 cm H2O, postinspiratory work by the inspiratory muscles (WOBPIIM) did not show significant change. The persistence and substantial values of WOBPIIM in some patients suggested the presence of significant patient-ventilator dyssynchrony, especially at higher levels of PS. Total inspiratory WOB per minute, including both patient WOB and WOB by the ventilator, increased by 186 +/- 29 percent, demonstrating that PS results in a respiratory pattern requiring substantially greater total mechanical work.
Aged↗
Effect of fast vs slow intralipid infusion on gas exchange, pulmonary hemodynamics, and prostaglandin metabolism.
Intralipid (20 percent, 500 ml) was infused fast (5 h) or slow (10 h) randomly in patients with lung injury to relate changes in plasma prostaglandin (PG) concentrations to gas exchange and pulmonary hemodynamics. Data were collected at baseline, midpoint of infusion, and 2 h following infusion. Vasodilator and vasoconstrictor PG metabolites, 6-keto-PGF1 alpha, and thromboxane B2, respectively, were measured in radial arterial blood samples. Slow Intralipid infusion increased shunt fraction (QS/QT) without changing mean pulmonary artery pressure (MPAP), whereas fast Intralipid infusion increased MPAP without changing QS/QT. Prostaglandin levels did not change significantly during either infusion. However, in both groups when the PG substrate was removed, hemodynamic and metabolite values decreased in parallel. In conclusion, we were unable to demonstrate a cause and effect relationship between plasma levels of 6-keto-PGF1 alpha and thromboxane B2 and the observed pulmonary hemodynamic response to slow or fast Intralipid infusion.
6-Ketoprostaglandin F1 alpha↗
Hemodynamic effects of pressure support ventilation in cardiac surgery patients.
Hemodynamic consequences of pressure support ventilation (PSV) were compared with intermittent mandatory ventilation (IMV) in 20 patients following aortocoronary bypass. On the morning following surgery, all patients were weaned by IMV to a rate of eight breaths per minute, tidal volume of 12 ml/kg and inspired oxygen concentration of 40 per cent. With patients awake and able to breath spontaneously, PSV was begun at 20 cm of water. In patients with static lung compliance, less than 0.06 l/cm H2O, 30 cm H2O of PSV was used. Subsequently, all patients were weaned to PSV 10 cm of water, continuous positive airway pressure (CPAP) at 5 cm water and extubated. Hemodynamic data including oxygen transport were obtained at each level of PSV and at IMV prior to weaning. Analysis using ANOVA showed comparable hemodynamic and oxygen transport parameters for PSV of 30 cm H2O in comparison with IMV. PSV at levels of 20 and 10 cm H2O produced statistically significant increases in heart rate, mean arterial pressure, central venous pressure, and pulmonary capillary wedge pressure. Cardiac output was stable, and these increases were not clinically significant. In awake patients following cardiac surgery, PSV up to 30 cm H2O can be safely applied without hemodynamic embarrassment in patients with good left ventricular ejection fractions.
Blood Gas Analysis↗