Indications for and results of single, bilateral, and heart-lung transplantation for pulmonary hypertension.

The indications for single, bilateral, and heart-lung transplantation for patients with pulmonary hypertension remain controversial. We retrospectively analyzed the results from 11 single, 22 bilateral, and 24 heart-lung transplant procedures performed between January 1989 and January 1993 on 57 consecutive patients with pulmonary hypertension caused by primary pulmonary hypertension (n = 27) or Eisenmenger's syndrome (n = 30). Candidates with a left ventricular ejection fraction less than 35%, coronary artery disease, or Eisenmenger's syndrome caused by surgically irreparable complex congenital heart disease received heart-lung transplantation. All other candidates received single or bilateral lung transplantation according to donor availability. Although postoperative pulmonary artery pressures decreased in all three allograft groups, those in single lung recipients remained significantly higher than those in bilateral and heart-lung recipients. The cardiac index improved significantly in only the bilateral and heart-lung transplant recipients. A significant ventilation/perfusion mismatch occurred in the single lung recipients as compared with bilateral and heart-lung recipients because of preferential blood flow to the allograft. Graft-related mortality was significantly higher and overall functional recovery as assessed by New York Heart Association functional class was significantly lower at 1 year in the single as compared with bilateral and heart-lung recipients. Thus bilateral lung transplantation may be a more satisfactory option for patients with pulmonary hypertension with simple congenital heart disease, absent coronary arterial disease, and preserved left ventricular function. Other candidates will still require heart-lung transplantation.

Pulse oximetry in the postoperative care of cardiac surgical patients. A randomized controlled trail.

STUDY OBJECTIVE: To demonstrate the utility of pulse oximetry in detecting clinically unapparent episodes of arterial desaturation in postoperative cardiac surgical patients and to evaluate the effect of pulse oximetry on ordering arterial blood gas analyses. DESIGN: Prospective, randomized, partially blinded comparison. SETTING: Cardiothoracic surgical intensive care unit. PATIENTS: 35 patients following elective cardiac surgical procedures. INTERVENTIONS: All patients were monitored continuously with pulse oximetry throughout their ICU course. In group 1 patients, the SpO2 data were available at the bedside. In group 2 patients, the SpO2 data were masked at the bedside and monitored at a remote location. MEASUREMENTS AND RESULTS: Utilization of pulse oximetry allowed a significant reduction in arterial blood gas utilization in group 1 (group 1: 12.4 +/- 7.5 blood gas analyses per ICU admission vs group 2: 23.1 +/- 8.8; p = 0.0007) without adverse events. Clinically unapparent desaturations were detected in 7 of 15 patients in group 2. CONCLUSIONS: Pulse oximetry improves patient safety through the detection of clinically unapparent episodes of desaturation and can allow a reduction in the number of blood gas analyses utilized without adverse effects to the patient. This may allow a potential cost savings to the patient.

Utility of prostaglandin E1 in the pretransplantation evaluation of heart failure patients with significant pulmonary hypertension.

Patients with chronic heart failure frequently have pulmonary hypertension. Because severe preoperative pulmonary hypertension predicts a poor outcome after orthotopic transplantation, pulmonary vasoreactivity is evaluated frequently in the pretransplantation screening of heart failure patients. We prospectively evaluated the utility of the direct pulmonary vasodilator, prostaglandin E1, and compared it to the nonspecific vasodilators, nitroglycerin and sodium nitroprusside, in the evaluation of pulmonary hypertension in 39 heart transplantation candidates. Prostaglandin E1 significantly lowered pulmonary artery pressure, transpulmonary pressure gradient, and pulmonary vascular resistance. An adequate pulmonary vasodilator response (defined as a decline in transpulmonary pressure gradient to less than 15 mm Hg) occurred in 31 patients (79%). In a subgroup of nine patients also tested with nitroglycerin, greater reductions (p less than 0.01) in both transpulmonary pressure gradient and pulmonary vascular resistance occurred with prostaglandin E1, compared to nitroglycerin. Five of six patients who did not respond to nitroglycerin responded to prostaglandin E1. In another subgroup of 12 patients who were also evaluated with sodium nitroprusside, prostaglandin E1 produced a larger decline (p less than 0.05) in transpulmonary pressure gradient and pulmonary vascular resistance than did sodium nitroprusside. Six of eight patients who did not respond to sodium nitroprusside responded to prostaglandin E1. Based on pulmonary vasodilator response to prostaglandin E1, 27 patients were accepted on the transplantation waiting list, and eight patients underwent orthotopic transplantation. Postoperatively, acute right ventricular failure of the donor heart developed in none of these patients. Significant hemodynamic improvement occurred by 24 hours and persisted through 4 weeks of postoperative follow-up in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Ongoing development of the Critical Care Information System: the collaborative approach to automating information management in an intensive care unit.

Point-of-care (bedside) clinical information systems can fulfill a variety of functions. Included in these functions are: becoming receptacles for patient data and allowing data to be manipulated into formats that facilitate clinical decision making; functioning as sources for billing and auditing processes; interfacing to other hospital systems and bringing distant data to the bedside; and being a repository for information used in the development of hierarchical and/or relational databases. The initial and ongoing development of these systems in a dynamic clinical environment requires the construction of processes and work pathways to ensure that the needs and requirements of myriad personnel, departments and agencies within the health center milieu are addressed.

Confirmation of endotracheal tube placement: a miniaturized infrared qualitative CO2 detector.

STUDY OBJECTIVES: A miniaturized, infrared, solid-state, end-tidal CO2 detector was used to confirm emergency endotracheal tube (ETT) placement. DESIGN: This prospective, clinical study used a miniature, infrared, solid-state end-tidal CO2 detector to confirm ETT placement in an acute setting. SETTING: The ICU, emergency department, and hospital floor. TYPE OF PARTICIPANTS: There were 88 consecutive adult patients requiring 100 emergency intubations. MEASUREMENTS AND MAIN RESULTS: The indication for airway intervention was considered urgent in 79% and under arrest conditions in 21%. The mean number of intubation attempts was 1.83 (range, one to five) with difficulty of intubation of 6.48 and confirmation of 7.75, on a linear scale from 0 (lowest) to 10 (highest). Determination of ETT position revealed intratracheal intubation in 96% and esophageal intubation in 4%. Placement was confirmed by direct visualization or radiography in all cases. Sensitivity and specificity for ETT localization was 100% (P less than .0001). CONCLUSION: This hand-held infrared capnometer reliably confirms ETT placement under emergency conditions.

Critical care management of lung transplant recipients.

In the last 10 years, lung transplantation has become an increasingly common procedure for patients with end-stage respiratory disease. Although long-term survival can be achieved, there is still significant morbidity within the first year. Early postoperative problems that may be anticipated include respiratory insufficiency, airway anastomotic problems, hemorrhage, infection, and episodes of acute rejection. These problems and others make the immediate perioperative period particularly challenging. With aggressive management, however, the probability of a successful outcome can be enhanced.

Torsades de pointes therapy with phenytoin.

We present the case of a woman with myocardial infarction complicated by malignant ventricular arrhythmia and torsades de pointes. The torsades de pointes was refractory to conventional therapy but responsive to phenytoin. This case suggests the clinical usefulness of phenytoin for adjunct therapy of life-threatening ventricular arrhythmias when standard treatment modalities fail.

Evolution of human cardiac myocyte dimension during prolonged mechanical support.

In animal models using left ventricular assist systems over long time periods, myocardial cellular atrophy has been reported, raising concern that prolonged clinical use of such systems might lead to deterioration in left ventricular function. At the University of Pittsburgh, long-term clinical use of the Novacor (Baxter Healthcare Corp., Novacor Div., Oakland, Calif.) left ventricular support system for patients awaiting heart transplants has allowed study of the effects of long-term mechanical support on human subjects. This study determined that cardiac myocyte dimension is initially greater in patients with end-stage cardiac disease who require support rather than in patients with the same disease who do not require such support. Although myocyte dimension does decrease within a few days of the inception of support, this decrease merely brings cell size closer to the values usual in patients with chronic end-stage cardiac disease, and no further shrinkage is observed. Thus the Novacor left ventricular assist system does not appear associated with left ventricular atrophy, and its long-term use may not be detrimental to left ventricular function.

Hemodynamic effects of synchronous high-frequency jet ventilation in mitral regurgitation.

We tested the hypothesis that increases in intrathoracic pressure (ITP), by decreasing the pressure gradient for anterograde left ventricular (LV) ejection, should augment cardiac output in acute mitral regurgitation (MR). In a pentobarbital-anesthetized closed-chest canine model, LV stroke volume (SLLV) was measured by integration from an aortic flow probe signal. MR was induced by a regurgitant ring. ITP was elevated over apnea by means of intermittent positive-pressure ventilation (IPPV), asynchronous (asynch) high-frequency jet ventilation (HFJV), and cardiac cycle-specific (synch) HFJV. IPPV resulted in the greatest increase in ITP. MR caused a fall in SVLV and a rise in LV filling pressure that were not altered by IPPV. Compared with IPPV or apnea, both asynch and synch HFJV increased SVLV and reduced LV filling pressures (P less than 0.05). Systolic synch HFJV induced a greater increase in SVLV (32%) than diastolic synch HFJV (26%) despite similar ventilatory settings. Our data suggest that when LV contractility is normal but MR impairs forward flow, cardiac cycle-specific increases in ITP will augment forward flow.

Depression and recovery of right ventricular function after cardiopulmonary bypass.

Transient left ventricular dysfunction is commonly described in association with cardiopulmonary bypass (CPB). We evaluated changes in right ventricular (RV) function after elective cardiac surgery in 24 patients with normal preoperative cardiac function. In all, irrespective of distribution of coronary artery disease or use of pharmacologic support, a transient depression of RV systolic function with respect to both preinduction and initial postoperative (Postop) values occurred 262 +/- 116 min post-CPB as represented by a decrease in RV stroke volume index (25.0 +/- 1.7 vs. 33.4 +/- 1.9 ml/m2 Postop) and RV ejection fraction (31.0 +/- 2.2 vs. 45.6 +/- 2.5% Postop), and an increase in RV end-systolic and end-diastolic volume indices. This depression responded readily to pharmacologic therapy within 2 h, resolved within 24 h, and had no adverse consequences in these otherwise healthy patients. Further studies are needed to identify the cause of this phenomenon and its importance in patients with preexisting cardiac dysfunction.

Clinical assessment of hemodynamic values in two surgical intensive care units. Effects on therapy.

A prospective study of 126 surgical patients from two institutions was undertaken to assess the impact of pulmonary artery catheterization in surgical intensive care units. Before catheterization, surgical residents were asked to predict pulmonary artery wedge pressure, cardiac output, systemic vascular resistance, and plan of therapy. After catheterization, each chart was reviewed by a panel of intensive care specialists and a general surgeon. Correct classification for the hemodynamic variables ranged from 47% to 55%. Catheterization results prompted a major change in therapy in 50% of patients. The data suggest that hemodynamic variables obtained from pulmonary artery catheterization improve the accuracy of bedside evaluation and lead to alteration in therapy, particularly in patients whose pulmonary artery wedge pressure predictions were poor.

Early and late tamponade with the Novacor left ventricular assist system.

Cardiac tamponade can be a major complication after implantation of the Novacor left ventricular assist system (LVAS). Between 1987 and 1989, 14 patients received an LVAS as a bridge to cardiac transplantation: 3 developed early tamponade (33 +/- 12 hr postoperatively) and 5 were diagnosed with a late tamponade (9.4 +/- 3.2 days postoperatively). One patient had both early and late tamponade. Early tamponade was more common in those with increased perioperative blood loss (5,270 +/- 1,942 ml vs. 1,420 +/- 1,160 ml in other patients, p less than 0.05). Early tamponade was suggested by reduction in mean arterial pressure (74 +/- 1 to 64 +/- 3 mmHg), LVAS output (5 +/- 0.5 to 2.7 +/- 0.7 L/min), LVAS stroke volume (55 +/- 4 to 23 +/- 5 ml), and an increase in central venous pressure (13 +/- 1 to 21 +/- 1 mmHg, p less than 0.05 for all values). Late tamponade was associated with a marked rise in central venous pressure (14 +/- 1 to 22 +/- 2 mmHg, p less than 0.05), with only a mild decrease in LVAS output (4.9 +/- 1 to 3.8 +/- 0.9 L/min) and stroke volume (49 +/- 8 to 36 +/- 3 ml), without a significant change in mean arterial pressure. Two of these five late episodes occurred in patients who were anticoagulated with heparin (PTT 52 and 100 sec), and in one other with warfarin (PT 27 sec, PTT 55 sec); two patients were not on any anticoagulants. Surgical drainage of pericardial effusions, and especially of clotted blood found frequently posterior to the left ventricle in the space created by the LVAS decompressed left ventricle, resulted in an immediate return of all hemodynamic measurements to normal in both early and late tamponade.

Acute myocardial dysfunction and recovery: a common occurrence after coronary bypass surgery.

To evaluate whether acute myocardial dysfunction was common in the early postoperative period, serial hemodynamic measurements and radionuclide evaluation of ventricular function were performed before and after operation in 24 patients undergoing elective coronary bypass surgery. All patients had uncomplicated surgery, and no patient sustained an intraoperative infarction. In 96% of patients, significant depression in right and left ventricular ejection fraction was seen postoperatively, reaching a nadir at 262 +/- 116 min after coronary bypass. Left ventricular ejection fraction was 58 +/- 12% preoperatively and 37 +/- 10% at trough. Right ventricular function displayed a similar pattern. These findings were also associated with depressed cardiac and left ventricular stroke work index despite maintenance of adequate ventricular filling pressures and mean arterial pressure. The depression in ventricular function was partially reversible within 8 to 10 h after surgery. Left ventricular ejection fraction had increased to 55 +/- 13% at 426 +/- 77 min after coronary bypass and showed complete recovery within 48 h. Left ventricular end-systolic and end-diastolic volume index increased significantly postoperatively, but recovery in left ventricular ejection fraction was mostly due to decreases in end-systolic volume index (50 +/- 22 ml at trough and 32 +/- 16 ml at recovery). Depressed myocardial function was independent of bypass time, number of grafts placed, preoperative medications or core temperatures postoperatively. Postoperative therapy with pressors or inotropic agents delayed but did not prevent the occurrence of postoperative ventricular dysfunction. Despite improvements in operative techniques and methods of myocardial protection, postoperative left ventricular dysfunction continues to be common in patients undergoing cardiopulmonary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of an oscillating bed in the prevention of lower respiratory tract infection in critically ill victims of blunt trauma. A prospective study.

We tested the hypothesis that the incidence of LRTI in critically ill blunt trauma victims can be reduced by employing continuous postural oscillation. Within 24 h of admission to the SICU, 106 patients were prospectively randomized to either a conventional bed or a RRKTT. Seven patients who were discharged from the SICU in less than 24 h were excluded from the data analyses. Until discharge from the SICU, patients were monitored daily for development of LRTI or pneumonia. Among 48 patients in the control group, 28 met criteria for LRTI and 19 met criteria for pneumonia. Among 51 patients in the RRKTT group, 13 developed LRTI and 7 developed pneumonia. The differences between groups for all LRTI and pneumonia were both significant. We conclude that continuous postural oscillation decreases the risk of pulmonary sepsis in victims of major blunt trauma.

The cardiopulmonary response to OKT3 in orthotopic cardiac transplant recipients.

Improvement in the outcome from cardiac transplantation can be attributed to recent advances in immunosuppression, including the use of OKT3, a new monoclonal antibody. The first dose of OKT3 induces side effects such as dyspnea in other transplant populations. We studied cardiopulmonary responses to OKT3 in 23 recipients of cardiac transplants. Despite pretreatment including antihistamines, hydrocortisone, and acetaminophen, OKT3 administered within 72 hours of transplantation, as part of prophylactic immunosuppression, induced a biphasic systemic response. Within the first hour, patients developed fever, hyperdynamia, hypertension, and tachycardia. By five to seven hours after the dose, there was mild hypotension, hypoxemia, and decreased indices of vascular resistance. Eighteen of the 23 patients required supplemental oxygen or vasopressor support (or both). Our findings define a complex cardiovascular response to OKT3 exhibited by the delayed noncoincident onset of hemodynamic instability, hypoxemia, and fever. Close observation in an ICU is recommended during the initial administration of OKT3 for prompt intervention when reactions occur.

Aminoglycoside pharmacokinetics: dosage requirements and nephrotoxicity in trauma patients.

We evaluated prospectively gentamicin and tobramycin pharmacokinetics in 37 patients with multiple system trauma and seven patients with isolated closed head trauma. The mean apparent volume of distribution (Vd) was 0.38 +/- 0.10 and 0.27 +/- 0.04 L/kg actual body weight (ABW) in patients with multiple trauma and closed head trauma, respectively. The difference in Vd between the two groups of patients was significant (p less than .002). Vd was not predictable on the basis of age, sex, weight, trauma score, or hospital day that therapy was initiated. Mean aminoglycoside clearance (Cl) was 123 +/- 46 ml/min. Neither serum creatinine nor estimated creatinine Cl predicted aminoglycoside Cl with sufficient accuracy to be clinically useful (r = .33 and .67, respectively). The mean daily dose was 6.1 +/- 1.6 mg/kg. The mean peak serum level was 5.8 +/- 1.3 micrograms/ml. Only one patient developed clinically significant renal dysfunction. Our data indicate that a loading dose of gentamicin or tobramycin of 3 mg/kg ABW in patients with multiple trauma and 2.5 mg/kg ABW in patients with isolated head trauma will obtain a mean initial peak serum level of 6.6 micrograms/ml. Although adequate maintenance dosing requires individualization based on pharmacokinetic analyses, large aminoglycoside doses can be used safely in patients with blunt trauma if appropriate monitoring is employed.

Systemic and regional hemodynamic effects of cyclo-oxygenase and thromboxane synthetase inhibition in normal and hyperdynamic endotoxemic rabbits.

We tested the hypothesis that prostaglandins (PGs) and thromboxane (Tx) A2 are important mediators of the hemodynamic derangements occurring in a rabbit model of hyperdynamic endotoxicosis. Rabbits were injected with either normal saline (NS) or Escherichia coli lipopolysaccharide (LPS; 1-3 micrograms/kg) and studied 6 hr later. Cardiac index (CI) and regional blood flow were determined using thermodilution and radioactive microspheres, respectively. Systemic and regional hemodynamics were determined before and 40 min after administering indomethacin (cyclo-oxygenase inhibitor; 5 mg/kg), UK38485 (Tx synthetase inhibitor; 10 mg/kg), or NS. LPS increased CI (P = .0024) and decreased mean arterial pressure (P = .0031) and systemic vascular resistance index (P = .0001). LPS increased flow to the heart and small intestine and decreased flow to the hepatic artery and pancreas. The systemic and regional hemodynamic effects of indomethacin were similar in NS- and LPS-treated rabbits. UK38485 decreased perfusion of skeletal muscle and diaphragm in both endotoxemic and control animals. This agent increased splenic perfusion only in NS-treated rabbits. Plasma levels of 6-keto PGF1 alpha (PGI2 metabolite) were typically undetectable in both NS- and LPS-treated rabbits. These data do not support the hypothesis that PG's or TxA2 are major determinants of the hemodynamic perturbations that occur in this endotoxicosis model.