Risk factors for surgical site infection after delayed sternal closure.

We examined the rates and risk factors for surgical site infections (SSIs) following delayed sternal closure after pediatric cardiac surgery by way of retrospective review of prospectively collected infection control data. Of 130 patients, 13.7% developed an SSI, and 6.9% developed mediastinitis following delayed sternal closure. There was a trend toward increased SSIs in patients undergoing delayed sternal closure in beds in the open bay of a pediatric intensive care unit.

Influence of Cheyne-Stokes respiration on ventricular response to atrial fibrillation in heart failure.

In subjects with sinus rhythm, respiration has a profound effect on heart rate variability (HRV) at high frequencies (HF). Because this HF respiratory arrhythmia is lost in atrial fibrillation (AF), it has been assumed that respiration does not influence the ventricular response. However, previous investigations have not considered the possibility that respiration might influence HRV at lower frequencies. We hypothesized that Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) would entrain HRV at very low frequency (VLF) in AF by modulating atrioventricular (AV) nodal refractory period and concealed conduction. Power spectral analysis of R-wave-to-R-wave (R-R) intervals and respiration during sleep were performed in 13 subjects with AF and CSR-CSA. As anticipated, no modulation of HRV was detected at HF during regular breathing. In contrast, VLF HRV was entrained by CSR-CSA [coherence between respiration and HRV of 0.69 (SD 0.22) at VLF during CSR-CSA vs. 0.20 (SD 0.19) at HF during regular breathing, P < 0.001]. Comparison of R-R intervals during CSR-CSA demonstrated a shorter AV node refractory period during hyperpnea than apnea [minimum R-R of 684 (SD 126) vs. 735 ms (SD 147), P < 0.001] and a lesser degree of concealed conduction [scatter of 178 (SD 56) vs. 246 ms (SD 72), P = 0.001]. We conclude that CSR-CSA entrains the ventricular response to AF, even in the absence of HF respiratory arrhythmia, by inducing rhythmic oscillations in AV node refractoriness and the degree of concealed conduction that may be a function of autonomic modulation of the AV node.

Provocation of ventricular ectopy by cheyne-stokes respiration in patients with heart failure.

STUDY OBJECTIVES: Previous reports have suggested an association between Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) and ventricular ectopy, but there has been relatively little evidence of a cause-effect relationship. The objective of this study was to determine whether CSR-CSA directly provokes ventricular ectopy and, if so, whether it is associated with any particular phase of the CSR-CSA breathing cycle. DESIGN: We compared the frequency of ventricular premature beats (1) between the apneic and hyperpneic phases of CSR-CSA, (2) between periods of CSR-CSA and periods of regular breathing during sleep, and (3) in response to the elimination of CSR-CSA by administration of a low concentration of inhaled CO2. SETTING: Hospital-based cardiopulmonary sleep laboratory. PATIENTS: Twenty-three patients with heart failure and CSR-CSA. MEASUREMENTS AND RESULTS: Ventricular premature beats were found to occur 40% more frequently during the hyperpneic phase than the apneic phase of CSR-CSA (mean+/-SD, 7.0+/-7.4 versus 4.9+/-5.7 ventricular premature beats per minute, P = .003). Ventricular premature beat frequency was also found to be higher during periods of CSR-CSA than during periods of regular breathing occurring either spontaneously (median [25th, 75th percentile], 2.2 [1.2, 6.5] versus 1.1 [0.8, 2.0] ventricular premature beats per minute, P = .027), or induced through inhalation of CO2 (from 4.7+/-3.8 to 3.3+/-4.0 ventricular premature beats per minute, P = .048). CONCLUSIONS: CSR-CSA provokes ventricular ectopy that is most pronounced during the hyperpneic phase. Such an increase in ventricular premature beats might contribute to the higher mortality rates reported in heart failure patients with CSR-CSA.

Avoidance of the left lateral decubitus position during sleep in patients with heart failure: relationship to cardiac size and function.

OBJECTIVES: We sought to determine whether patients with congestive heart failure (CHF) avoid the left lateral decubitus (LLD) position during sleep and, if so, whether this avoidance would be more pronounced in those with greater degrees of cardiomegaly. BACKGROUND: Anecdotal reports suggest that, in patients with CHF, the LLD position is associated with discomfort due to the enlarged apical heart beat and greater degree of dyspnea (trepopnea) than other positions. It has also been suggested that the LLD position is associated with increased sympathetic nervous activity. METHODS: A total of 75 patients with CHF and 75 control subjects underwent nocturnal polysomnography with monitoring of body position. Echocardiography was performed in all patients with CHF to determine left ventricular end-diastolic diameter (LVEDD). A total of 40 patients underwent cardiac catheterization from which pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were obtained. RESULTS: Patients with CHF spent significantly less time in the LLD position than in the right lateral decubitus position. No such difference was observed among control subjects. Among patients with CHF, those with larger LVEDD, higher PCWP, and lower CO spent less time in the LLD position. CONCLUSIONS: Patients with CHF avoid the LLD position spontaneously during sleep. This may be a protective strategy to avoid discomfort from the enlarged apical heart beat or further hemodynamic or autonomic compromise.