Non-tuberculous mycobacteria in end stage cystic fibrosis: implications for lung transplantation

BACKGROUND

WC and NS contributed equally. Non-tuberculous mycobacteria (NTM) frequently colonise patients with end stage cystic fibrosis (CF), but its impact on the course of the disease following lung transplantation is unknown.

METHODS

Lung transplant recipients with CF who underwent lung transplantation at our institution between January 1990 and May 2003 (n=146) and CF patients awaiting lung transplantation in May 2003 (n=31) were studied retrospectively.

RESULTS

The prevalence rate of NTM isolated from respiratory cultures in patients with end stage CF referred for lung transplantation was 19.7%, compared with a prevalence rate of 13.7% for NTM isolates in CF lung transplant recipients. The overall prevalence of invasive NTM disease after lung transplantation was low (3.4%) and was predicted most strongly by pre-transplant NTM isolation (p=0.001, Fisher's exact test, odds ratio (OR) 6.13, 95% CI 3.2 to 11.4). This association was restricted to Mycobacterium abscessus (p = 0.005, Fisher's exact test, OR 7.45, 95% CI 2.9 to 16.9). While NTM disease caused significant morbidity in a small number of patients after transplantation, it was successfully treated and did not influence the post-transplant course of the disease.

CONCLUSION

The isolation of NTM before transplantation in CF patients should not be an exclusion criterion for lung transplantation, but it may alert the clinician to patients at risk of recurrence following transplantation.

Outcomes of intensive care unit care in adults with cystic fibrosis

Cystic fibrosis (CF) causes progressive respiratory failure and death in more than 90% of patients. Mechanical ventilation has been discouraged in CF because of poor outcomes, but improved survival and the availability of lung transplantation have increased the indications for care of CF patients in the intensive care unit (ICU). We studied the outcomes of all CF patients admitted to the University of North Carolina Hospitals Medical ICU from January 1990 through December 1998. Seventy-six patients, ranging in ages from 17 to 45 yr (mean: 27 yr), and of whom 53% were female, had 136 admissions for exacerbations of CF with respiratory failure (RF, n = 65), hemoptysis (n = 33), antibiotic desensitization (n = 30), pneumothorax (n = 3), or other reasons (n = 5). Eighty-six percent of the patients with hemoptysis and all of those with desensitization and pneumothorax were alive 1 yr after ICU discharge. Of the 42 patients with RF, 37 (88%) required assisted ventilation. Twenty-three (55%) of the patients with RF survived to ICU discharge and 19 (45%) died. Seventeen (40%) of the patients with RF received lung transplants and 14 were alive 1 yr later. Without transplantation, three (7%) of the patients with RF were alive and three (7%) were dead 1 yr later. Sex, body mass index, and respiratory bacteria did not correlate with survival. We conclude that ICU care for adults with CF who have reversible complications is appropriate and effective. Ventilatory support is appropriate for some transplant candidates.

Lung transplantation for cystic fibrosis: effective and durable therapy in a high-risk group

BACKGROUND

The purpose of this study was to review our experience with lung transplantation in patients with end-stage cystic fibrosis.

METHODS

Eight-two patients with cystic fibrosis have undergone bilateral lung transplantation (n=76) or bilateral lower lobe transplantation (n=6) since October 1990.

RESULTS

Actuarial survival for the entire cohort is 79% at 1 year and 57% at 5 years. The development of bronchiolitis obliterans syndrome is the leading cause of death after the first year. Freedom from bronchiolitis obliterans syndrome is 84% at 1 year and 51% at 3 years. Pulmonary function tests improve dramatically in recipients. There was no association between death within 1 year and recipient age, weight, graft ischemic time, cytomegalovirus seronegativity, or the presence of pan-resistant organisms. Similarly, there was no association between the development of bronchiolitis obliterans syndrome within 2 years and ischemic time, number of rejection episodes, cytomegalovirus seronegativity, or the presence of panresistant organisms.

CONCLUSIONS

Despite their poor nutritional status and the presence of multiply resistant organisms, patients with cystic fibrosis can undergo bilateral lung transplantation with acceptable morbidity and mortality.

Saprophytic fungal infections and lung transplantation--revisited

BACKGROUND

Fungal infections cause serious morbidity and death in lung transplant recipients. Some centers exclude and others will prophylactically treat patients with evidence of Aspergillus colonization.

METHODS

Of 126 patients undergoing lung transplantation at the University of North Carolina since January 1990, five patients have died because of invasive Aspergillus and other saprophytic fungal infections. Those cases are reviewed looking for common predisposing factors, including any evidence of prior colonization. In addition, all preoperative and postoperative culture data on all transplant recipients were retrospectively examined to define the prevalence of preoperative and postoperative Aspergillus colonization in 121 patients with and without cystic fibrosis, none of whom had development of significant fungal disease.

RESULTS

Fifty-two percent of 65 patients with cystic fibrosis were colonized with Aspergillus before operation, and 40% after operation at some time. None had development of significant Aspergillus infections, and none received prophylactic antifungal therapy. Most of the deaths from deep-seated fungal infections have been in patients without cystic fibrosis with no evidence of preoperative colonization. These patients had evidence of severe obliterative bronchiolitis, bacterial infections, persisting cytomegalovirus disease, or other major organ failure.

CONCLUSION

The rationale for excluding patients or for giving amphotericin in the perioperative period in those patients who are colonized before surgery is questioned.

Seizures in lung transplant recipients

PURPOSE

We wished to assess organ transplant recipients, who incur a significant risk for seizures.

METHOD

We reviewed 85 lung transplants performed in 81 patients at the University of North Carolina hospitals between 1991 and 1994. All patients were reviewed for age, reason for transplant, detailed description of seizures, neurological examination, medications, and laboratory results, including cyclosporine level, EEG, and brain imaging.

RESULTS

Eighteen of 81 (22%) patients experienced seizures. Patients aged < 25 years had the greatest risk of seizures and 15 of the 18 patients had cystic fibrosis. Sixteen of the 18 (89%) patients, by history, had partial-onset seizures. Eleven of the 18 (61%) patients had seizures < or = 10 days after initiation of intravenous methylprednisolone for allograft rejection. Two patients had seizures associated with sustained hypertension: 1 of these patients was simultaneously being treated for rejection. Four patients had strokes (1 before transplant) and seizures. Two patients were receiving imipenem. Magnetic resonance imaging (MRI) of the brain demonstrated areas of increased T2 signal in 8 of 9 patients.

CONCLUSIONS

Our findings demonstrate multiple etiologies for seizures in our transplant recipients. However, we believe that patients, especially those aged < 25 years, being treated with intravenous methylprednisolone for rejection may be at increased risk of seizures. We hypothesize that the focal loss of blood-brain barrier (BBB) may play a significant role in the development of partial seizures in lung transplant recipients.

Atrial anastomotic thrombus causes neurologic deficits in a lung transplant recipient

Pulmonary thrombus formation in the region of atrial anastomosis following lung transplantation has been reported by several authors. Such patients typically present immediately after surgery with significant hemodynamic compromise causing pulmonary edema and hypoxemia. We describe a patient who presented with bilateral neurologic deficits 4 and 6 weeks after lung transplantation. Despite a normal transthoracic echocardiogram, transesophageal echocardiography (TEE) detected a large left atrial thrombus adherent to the atrial anastomosis. This thrombus was treated with intravenous heparin and subsequently warfarin. After 3 weeks, a repeat TEE demonstrated complete resolution of the lesion. This case demonstrates that postoperative left atrial and pulmonary venous thrombi may provide the basis for serious patient morbidity without hemodynamic or radiographic clues to their presence, that TEE is superior to transthoracic echocardiography for detecting left atrial thrombi, and that such lesions can respond to medical management alone.

Analysis of cystic fibrosis referrals for lung transplantation

Patients with cystic fibrosis (CF) are being considered in increasing numbers as candidates for lung transplantation, despite earlier concerns that their nutritional status and the infective nature of their lung disease would contribute to increased morbidity and mortality. We undertook a retrospective analysis of patients with CF referred for consideration of lung transplant to identify factors that helped to select suitable transplant candidates and to identify characteristics that predicted death while on the waiting list. Analysis of 95 referred patients with CF demonstrated a high rate of suitability (78%) by our criteria. The mean weight of listed patients with CF was 77% predicted, and the mean FEV1 was 20% predicted. Sixteen percent of listed patients with CF died awaiting transplant. The FEV1 of these patients was significantly lower than that of patients who survived to transplant. This study implies that patients with CF are being referred for transplant late in the course of their disease. Earlier referral may lead to an increase in the number of patients with CF undergoing successful lung transplantation.

Effect of size (mis)matching in clinical double-lung transplantation

Current United Network for Organ Sharing policy requires listing lung transplant recipients with an acceptable donor weight range, but lung size is a function of height, age, sex, and race. Frequently, lung transplant recipients are underweight, which results in a large discrepancy between donor and recipient weights. We reviewed our experience with size discrepancy between donors (D) and recipients (R) of 49 double-lung transplant (DLTX) procedures since July 1990. Pneumoreduction procedures were performed in 11 recipients of lungs judged to be too large at the time of DLTX (right middle lobectomy, 2; lingulectomy, 2; both, 6; right middle lobectomy and bilateral apical resections, 1). Predicted forced vital capacity (FVC) and total lung capacity (TLC) of donors and recipients were calculated. Donors were larger than recipients in general (D:R height = 1.02; D:R weight = 1.46), and, as a result, recipient-predicted lung volumes were smaller than donor-predicted lung volumes (D:R FVC = 1.1; D:R TLC = 1.1). Recipients undergoing pneumoreduction procedures had a significantly greater size discrepancy between donors and recipients; thus, both the ratio of D:R and the difference between D and R predicted FVC and TLC were significantly greater among recipients who underwent pneumoreduction, compared with nonreduced recipients. For recipients in the pneumoreduction group, predicted FVC and TLC were recalculated, with a proportionate amount subtracted based on the number of pulmonary segments removed. When the "corrected" FVC and TLC of the donors were compared with recipient-predicted FVC and TLC, there was no longer any significant difference between reduced and non-reduced groups, which implies that visual estimate of size mismatch at surgery is an accurate measure of size discrepancy. Post-DLTX spirometry showed identical improvement in FVC in patients who had pneumoreduction and those who did not, and survival at 6 months was identical in both groups. We conclude that pneumoreduction had no adverse effect on survival or post-DLTX spirometry, allowing safe use of larger donors in small recipients. Also, because lung size is more a function of height than weight, this study challenges the United Network for Organ Sharing practice of listing recipients with an acceptable donor weight range.

Improved results of lung transplantation for patients with cystic fibrosis

Patients with cystic fibrosis pose particular challenges for lung transplant surgeons. Earlier reports from North American centers suggested that patients with cystic fibrosis were at greater risk for heart-lung or isolated lung transplantation than other patients with end-stage pulmonary disease. During a 3 1/2 year period, 44 patients with end-stage lung disease resulting from cystic fibrosis underwent double lung transplantation at this institution. During the same interval, 18 patients with cystic fibrosis died while waiting for lung transplantation. The ages of the recipients ranged from 8 to 45 years, and mean forced expiratory volume in 1 second was 21% predicted. Seven patients had Pseudomonas cepacia bacteria before transplantation. Bilateral sequential implantation with omentopexy was used in all patients. There were no operative deaths, although two patients required urgent retransplantation because of graft failure. Cardiopulmonary bypass was necessary in six procedures in five patients and was associated with an increased blood transfusion requirement, longer postoperative ventilation, and longer hospital stay. Actuarial survival was 85% at 1 year and 67% at 2 years. Infection was the most common cause of death within 6 months of transplantation (Pseudomonas cepacia pneumonia was the cause of death in two patients), and bronchiolitis obliterans was the most common cause of death after 6 months. Actuarial freedom from development of clinically significant bronchiolitis obliterans was 59% at 2 years. Results of pulmonary function tests improved substantially in survivors, with forced expiratory volume in 1 second averaging 78% predicted 2 years after transplantation. Double lung transplantation can be accomplished with acceptable morbidity and mortality in patients with cystic fibrosis.

Infectious complications of lung transplantation. Impact of cystic fibrosis

It has been suggested that the presence of airway pathogens prior to lung transplantation (LT) in patients with cystic fibrosis (CF) may place these patients at a higher risk for infectious complications after LT. There is particular concern regarding patients colonized with multiresistant Pseudomonas, including P. cepacia, and fungi, including Aspergillus. We report our experience with LT for patients with CF and compare the results with those of patients with LT for other indications. Between January 1990 and March 1993, we performed LT for 27 patients with CF and 32 without CF. Nearly all (89%) of the patients with CF were colonized with P. aeruginosa; many were cultured with P. cepacia (19%) and Aspergillus (63%). The non-CF group rarely had organisms identified pre-LT. No patients with CF underwent pre-LT sinus drainage or received pre-LT treatment for Aspergillus. All of the patients received perioperative antibiotics and a standard regimen of immunosuppression and prophylactic antibiotics. The incidence of infectious complications was the same in the two groups; however, there was an association between obliterative bronchiolitis and pulmonary infections. One of the patients with CF with P. cepacia died as a result of this organism. None of the patients with CF required treatment for Aspergillus post-transplant. We conclude that patients with CF, despite the presence of airway pathogens, are at no greater risk of infectious complications after LT than are other patients.

Lung transplantation for mechanically ventilated patients

As lung transplantation has become more successful, the selection criteria have broadened; however, some relative contraindications to lung transplantation are controversial. Some programs consider mechanical ventilation to be a major contraindication to lung transplantation because airway colonization with bacteria may lead to nosocomial infection and respiratory muscle deconditioning may necessitate prolonged postoperative ventilatory support. We report our experience of seven double lung transplant procedures on six patients requiring mechanical ventilation. Five patients with cystic fibrosis required preoperative mechanical ventilation for 7 to 19 days (mean, 10.7 days). One patient with acute lung injury required 115 days of preoperative mechanical ventilatory support. Only the latter patient required prolonged (27 days) postoperative mechanical ventilation because of respiratory muscle weakness; the others were extubated in 1 to 19 days (mean, 7.8 days). No early complications related to bacterial infection were seen. Two patients required temporary hemodialysis for transient kidney failure. Three patients had postoperative neurologic residua; one patient had a transient hemiparesis, and seizures developed in two patients. One patient died 3 months after transplantation from severe central nervous system complications with no evidence of pulmonary problems; and two patients died 17 months after transplantation, one of them receiving a second double lung transplant for obliterative bronchiolitis. Except for the patient who required prolonged preoperative ventilatory support, mechanical ventilation did not appear to play a role in the outcome of these patients. The posttransplantation hospital stay and hospital charges for patients requiring pretransplantation ventilatory support were not significantly different from those for other lung transplant recipients.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholelithoptysis. A complication following laparoscopic cholecystectomy

A 59-year-old woman who underwent laparoscopic cholecystectomy for symptomatic cholecystitis presented four months later with fever, malaise, anorexia, hemoptysis and lithoptysis. Chemical analysis of the expectorated lithes revealed them to be gallstones. Ultrasound studies of the right upper quadrant demonstrated both supradiaphragmatic and subdiaphragmatic fluid collections containing echogenic fragments. ERCP failed to demonstrate retained ductal stones or fistula formation. To our knowledge, this is the first reported case of cholelithoptysis and demonstrates an unusual complication of gallstone retention following laparoscopic cholecystectomy.

Isolated lung transplantation for end-stage lung disease: a viable therapy

Since January 1990, we have performed 29 isolated lung transplantations in 28 patients with end-stage lung disease (12 single, 16 bilateral). Recipient diagnoses were: cystic fibrosis (11), chronic obstructive pulmonary disease (6), pulmonary fibrosis (6), eosinophilic granulomatosis (1), postinfectious lung disease (1), adult respiratory distress syndrome (1), and primary pulmonary hypertension (2). There have been four deaths, two in patients with pulmonary fibrosis and two in patients with primary pulmonary hypertension. Four patients have undergone transplantation while on ventilatory support for respiratory failure (2 with cystic fibrosis, 1 having redo lung transplantation with cystic fibrosis, and 1 with adult respiratory distress syndrome); all of these have survived. Six patients required cardiopulmonary bypass, which was associated with increased transfusion requirement. All patients 2 months after discharge have returned to an active life-style, except for 2 patients who currently await retransplantation. Preoperative pulmonary rehabilitation has resulted in significant improvement in exercise performance in all patients. Immunosuppression consists of cyclosporine, azathioprine, and antilymphoblast globulin (University of Minnesota), withholding systemic steroids in the early postoperative period. We have employed bronchial omentopexy in all but four transplants; there has been one partial bronchial dehiscence, two instances of bronchomalacia requiring internal stenting, and one airway stenosis. Cytomegalovirus disease has been seen frequently (15 cases), but has responded well to treatment with ganciclovir. Other complication shave included one drug-related prolonged postoperative ventilation, thrombosis of a left lung after bilateral lung transplantation requiring retransplantation, five episodes of unilateral phrenic nerve palsy after bilateral lung transplantation (4 resolved), and the requirement of massive transfusion (greater than 10 units) in 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of pulmonary arterial input impedance with lumped parameter models

Page H587: B. J. B. Grant and L. J. Paradowski. “Characterization of pulmonary arterial input impedance with lumped parameter models.” Equations 5 and 6 should appear as the following.

(See PDF)

Characterization of pulmonary arterial input impedance with lumped parameter models

Page H587: B. J. B. Grant and L. J. Paradowski. “Characterization of pulmonary arterial input impedance with lumped parameter models.” Equations 5 and 6 should appear as the following.

(See PDF)

Dynamic response of local pulmonary blood flow to alveolar gas tensions: experiment

The purpose of this study was to investigate the mechanism that causes a damped oscillatory response of local pulmonary blood flow to local hypoxia. The left lower lobe (LLL) of 10 anesthetized dogs was ventilated independently but synchronously with the rest of the lungs. Blood flow to the LLL as a proportion of total flow (QLLL/QT) was measured during the on-transient of the hypoxic response when LLL inspirate was changed from O2 to N2. There was a damped oscillatory response of QLLL/QT to hypoxia (34 of 40 trials). In contrast, the off-transient was always monotonic. There was no enhancement of the steady state or dynamic hypoxic response with repeated challenges. Local alveolar hypercapnia caused a damped oscillatory response in the presence of local hypoxia (15 of 20 trials), but there was no response in the presence of local hyperoxia. We conclude that 1) the dynamic pulmonary vascular response to O2 and CO2 are not additive because the response to CO2 is attenuated by hyperoxia and 2) the damped oscillatory response that occurs during hypoxia is the result of changes of local alveolar CO2 per se.

Effect of perivascular electromagnetic flow probes on pulmonary hemodynamics

We determined the effect of perivascular electromagnetic flow probes (EMF) on pulmonary hemodynamics in acute experiments. In seven dogs placement of the EMF on the main pulmonary artery (MPA) increased pulmonary arterial pulse pressure by 25% (17.8-21.9 cmH2O, P less than 0.005) and mean right ventricular pressure by 12% (23.2-25.9 cmH2O, P less than 0.001) but did not alter heart rate, systemic blood pressure, mean pulmonary arterial pressure, or right ventricular end-diastolic pressure. This response was not abolished by local application of lidocaine to the MPA. In three cats input impedance was calculated from measurements of pressure and flow in the MPA. Impedance was calculated with flow measured using an EMF and ultrasonic volume flow probe (USF), which avoids the constraining effect of the EMF. When flow was measured with an EMF rather than a USF, there was a significant difference in the impedance spectra (P less than 0.001), but it was only apparent in the moduli greater than six harmonics. We conclude that the EMF does affect right ventricular afterload in acute experiments and alters the measured input impedance.

Characterization of pulmonary arterial input impedance with lumped parameter models

The purpose of this study is to evaluate systematically the ability of lumped parameter models to approximate pulmonary arterial input impedance (Zin) and estimate characteristic impedance (Zc) and pulmonary arterial compliance (Cart). To assess goodness of fit, the parameters of each model were adjusted so that the model's impedance approximates the Zin measured in anesthetized cats. To assess the ability of the model to estimate Zc and Cart, the lumped parameter models were fitted to Zin calculated from a distributed parameter model of the feline pulmonary vasculature. In addition, we assessed the concordance between the lumped parameter model estimates of Zc and Cart. The results indicate that no one model was superior; any of four models would be a reasonable choice. A four-element model was used to compare Zin measured at different phases of the respiratory cycle. Small differences in the impedance spectra were found that have not been previously reported. We conclude that lumped parameter models can be used to provide close approximations to Zin, to estimate Zc and Cart, and to provide a useful approach for statistical comparisons of impedance spectra.