Objective: Heart transplant studies have shown that following transplantation patients’ blood pressure (BP)circadian rhythms may be altered and levels elevated. These changes are partially attributed to the side effects of immunosuppressive medications. This study sought to determine whether similar alterations occur after lung transplantation. The objectives were to describe changes in circadian rhythm patterns and mean levels of BP. In addition, BP load was examined because it is proposed to correlate higher with end organ damage than BP levels. BP load is defined as the percent of values >140/90 mm Hg during the day and >120/80 during the night.
Design: A longitudinal, repeated measures and time series design was used.
Population, Sample, Setting: The sample consisted of 19 subjects (mean ± SD; 47±13 years; 13 females and 6 males). The most common underlying respiratory diagnoses were emphysema, cystic fibrosis, and pulmonary fibrosis. The majority of the subjects underwent bilateral, sequential lung transplantation. The setting was an urban, university medical center.
Methods: Data were collected pre-transplant, and at 1, 3, and 6 months post transplant. An ambulatory blood pressure monitoring system (SpaceLabs-Model 90207) was programmed to record patients’ blood pressure every hour for 48 hours. The subjects' midpoint of sleep was used as a zero point to allow for comparisons. MANOVA, cosinor and harmonic analyses were used to analyze the data.
Findings: Pre-transplant more than 70% of subjects demonstrated circadian rhythms with peak values (acrophases) occurring at the typical time. In contrast, at 1 and 3 months post transplant less than 35% of the subjects and at 6 months only slightly more than 50% of the subjects demonstrated BP circadian rhythms and most of rhythms were phase-shifted. In addition, a significant (p< .005) increase in BP was seen overtime such that the 1, 3, and 6 months post-transplant blood pressure levels were higher than the pre transplant levels. A marked increase in post transplant BP load, especially at night, was also demonstrated.
Conclusions: Similar to research on other solid organ transplant recipients, post lung transplant elevations in BP levels and alterations in circadian rhythms were demonstrated. In addition, marked increases in BP load were also found. Nine previously normotensive subjects were receiving antihypertensive medications 6 months after transplantation.
Implications: The alterations in circadian rhythm patterns are indicative of alterations in the subjects’ homeostatic status. The slight improvement in the percentage of subjects demonstrating BP circadian rhythms as post transplant time increased may reflect the recovery trajectory. Ambulatory BP monitoring was shown to be beneficial in detecting early signs of hypertension and provided an opportunity to refer patients for treatment of hypertension when indicated. This study is significant to nursing and healthcare because it describes physiological response patterns, and the findings indicate the need for longitudinal monitoring to detect and treat early signs of hypertension, a co-morbidity associated with organ transplantation.
Back to Studies in Interventions and Outcomes
Back to The Advancing Nursing Practice Excellence: State of the Science