Most children with functionally univentricular hearts nowadays are treated surgically by creating a total cavopulmonary connection. In the resulting Fontan circulation, the venous return and the pulmonary arterial bed are coupled in series, bypassing the heart. This gives the potential for interaction between the abnormal circulation and function of the lungs. In this study, we investigated the pattern of impairment of pulmonary function, and its relation to decreased exercise capacity. We performed spirometry in 33 (85 percent) of 39 eligible Norwegian children, aged from 8 to 16, with a total cavopulmonary connection, along with whole body plethysmography, the carbon monoxide single breath test, and a peak treadmill exercise test. The single breath test showed a mean corrected diffusing capacity of 66.5 percent of predicted, giving a z score of minus 2.88. The mean residual volume measured by whole body plethysmography was 146.8 percent, equivalent to a z score of 2.46, whereas the mean residual volume measured by the single breath test was 102.4 percent of predicted, this being the same as a z score of 0.43. The mean peak treadmill exercise test was 70.0 percent of predicted, equivalent with a z score of minus 3.07. Mean forced vital capacity was 85.7 percent of predicted, the equivalent z score being minus 0.92. Lung function correlated with the peak treadmill exercise test. We have shown, therefore, that children with the Fontan circulation have reduced diffusing capacity, possibly caused by the abnormal circulation through the lungs. The difference between residual volume measured by plethysmography and the single breath test implies trapping of air. The correlation of parameters for lung function with peak consumption of oxygen during exercise indicates that the abnormalities of pulmonary function may affect physical capacity.

Objective: To assess the consequences of hypoxaemia and resuscitation with room air versus 100% O 2 on cardiac troponin I (cTnI), cardiac output (CO), and pulmonary artery pressure (PAP) in newborn pigs. Design: Twenty anaesthetised pigs (12-36 hours; 1.7-2.7 kg) were subjected to hypoxaemia by ventilation with 8% O 2 . When mean arterial blood pressure fell to 15 mm Hg, or arterial base excess was ( 220 mmol/l, resuscitation was performed with 21% (n = 10) or 100% (n = 10) O 2 for 30 minutes, then ventilation with 21% O 2 for 120 minutes. Blood was analysed for cTnI. Ultrasound examinations of CO and PAP (estimated from tricuspid regurgitation velocity (TR-Vmax)) were performed at baseline, during hypoxia, and at the start of and during reoxygenation. Results: cTnI increased from baseline to the end point (p,0.001), confirming a serious myocardial injury, with no differences between the 21% and 100% O 2 group (p = 0.12). TR-Vmax increased during the insult and returned towards baseline values during reoxygenation, with no differences between the groups (p = 0.11) or between cTnI concentrations (p = 0.31). An inverse relation was found between increasing age and TR-Vmax during hypoxaemia (p = 0.034). CO per kg body weight increased during the early phase of hypoxaemia (p,0.001), then decreased. Changes in CO per kg were mainly due to changes in heart rate, with no differences between the groups during reoxygenation (p = 0.298). Conclusion: Hypoxaemia affects the myocardium and PAP. During this limited period of observation, reoxygenation with 100% O 2 showed no benefits compared with 21% O 2 in normalising myocardial function and PAP. The important issue may be resuscitation and reoxygenation without hyperoxygenation. M yocardial dysfunction, hypotension, and increased pulmonary vascular resistance are well known consequences of hypoxic-ischaemic insults in neonates, 1 with a relation between low alveolar oxygen tension and increased pulmonary vascular resistance.2 In contrast with chronic hypoxia, the effects are reversible with reoxygenation after insults of short duration.

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A large surgical shunt size is related to stiffer lungs and a large heart is associated with a higher respiratory resistance. During mechanical ventilation of patients with univentricular heart physiology the end-tidal CO2 may be an unreliable substitute for arterial CO2 before the bidirectional cavopulmonary connection. We found a relationship between a decreased pulmonary to systemic shunt ratio and an increased arterial to end-tidal CO2 difference. This may indicate that a reason for the unreliability of end-tidal CO2 is an impaired gas exchange partially due to pulmonary hypoperfusion.

This study estimates the effects on peak oxygen uptake (VO ), QoL, and mental health after the introduction of an adjusted post-transplant follow-up program, that is, early physiotherapy and focus on the importance of physical activity. VO was measured by a treadmill exercise test in 20 renal-transplanted children on the adjusted post-transplant follow-up and compared with a group of 22 patients investigated in a previously, before the implementation of our new follow-up routines. PedsQL and The Strengths and Difficulties Questionnaire (SDQ) were used to assess QoL and mental health in 45 patients on the new as compared to 32 patients on the previous follow-up strategy. The patients exposed to early physiotherapy and a higher focus on physical activity had significantly higher VO (44.3 vs 33.5 mL kg min , P = .031) in addition to improved QoL (P = .003) and mental health scores (P = .012). The cardiovascular risk profile was similar in both groups aside from significantly higher triglycerides in the present cohort. Small efforts as early physiotherapy and increased focus on physical activity after pediatric renal transplantation have significant impact on cardiorespiratory fitness, QoL, and mental health. The importance of physical activity should therefore be emphasized in follow-up programs.