Impact of diaphragmatic paralysis after cardiothoracic surgery in children

In a porcine model of implantable pacemakers for pediatric unilateral diaphragm paralysis, the phrenic nerve is the best target

BACKGROUND

A frequent complication of Fontan operations is unilateral diaphragmatic paresis, which leads to hemodynamic deterioration of the Fontan circulation. A potential new therapeutic option is the unilateral diaphragmatic pacemaker. In this study, we investigated the most effective stimulation location for a potential fully implantable system in a porcine model.

METHODS

Five pigs (20.8 ± 0.95 kg) underwent implantation of a customized cuff electrode placed around the right phrenic nerve. A bipolar myocardial pacing electrode was sutured adjacent to the motor point and peripherally at the costophrenic angle (peripheral diaphragmatic muscle). The electrodes were stimulated 30 times per minute with a pulse duration of 200 µs and a stimulation time of 300 ms. Current intensity was the only variable changed during the experiment.

RESULTS

Effective stimulation occurred at 0.26 ± 0.024 mA at the phrenic nerve and 7 ± 1.22 mA at the motor point, a significant difference in amperage (p = 0.005). Even with a maximum stimulation of 10 mA at the peripheral diaphragm muscle, however, no effective stimulation was observed.

CONCLUSION

The phrenic nerve seems to be the best location for direct stimulation by a unilateral thoracic diaphragm pacemaker in terms of the required amperage level in a porcine model.

Pulmonary blood flow in children with univentricular heart and unilateral diaphragmatic paralysis

OBJECTIVES

Spontaneous breathing has an important effect on pulmonary arterial blood flow in patients with Glenn/Fontan circulation. Unilateral diaphragmatic paralysis (DP) is a frequent complication after heart surgery in congenital heart disease. The aim of this study was to investigate the influence of unilateral DP on blood flow distribution in the pulmonary arteries with Glenn/Fontan circulation.

METHODS

Magnetic resonance phase-contrast imaging was used to evaluate stroke volume index (SVI) in the left and right pulmonary arteries in patients with Glenn/Fontan circulation with unilateral DP. Data for 18 patients with univentricular heart and unilateral DP were analysed, 8 in the Glenn stage and 10 in the Fontan stage. Ten patients had right-sided DP, and 8 had left-sided DP. A diaphragmatic plication was performed in 7 patients. The control group consisted of 36 patients with Glenn (n = 16)/Fontan (n = 20) circulation without DP.

RESULTS

In both left- and right-sided DP, the SVI to the ipsilateral side was significantly lower than in controls [2.81 (1.45-4.50) ml/m2 left vs 11.97 (7.36-16.37) ml/m2 in controls, P < 0.0002; 8.2 (4.49-12.64) ml/m2 with right vs 12.64 (9.66-16.61) ml/m2 in controls; P = 0.0284]. The SVI to the contralateral side showed a slight but non-significant increase in the presence of unilateral DP.

CONCLUSIONS

Unilateral DP in patients with Glenn/Fontan circulation has a negative impact on pulmonary arterial SVI on the side of the paralysis.

Towards Zero Phrenic Nerve Injury in Reoperative Pediatric Cardiac Surgery: The Value of Intraoperative Phrenic Nerve Stimulation

BACKGROUND

Phrenic nerve injury is a devastating complication that results in significant morbidity and mortality. We developed a novel technique to localize the phrenic nerve and evaluate its success.

METHODS

Two groups of children underwent repeat sternotomy for a variety of indications. Group I (69 patients, nerve stimulator) and Group II (78 patients, no nerve stimulator).

RESULTS

There was no significant difference in the mean age and weight between the two groups: (6.4 ± 6.5 years vs. 5.6 ± 6.4 years; p = 0.65) and (25.2 ± 24.1 vs. 22.6 ± 22.1; p = 0.69), respectively. The two groups were comparable in the following procedures: pulmonary conduit replacement, bidirectional cavopulmonary anastomosis, aortic arch repair, and Fontan, while Group I had more pulmonary arterial branch reconstruction (p = 0.009) and Group II had more heart transplant patients (p = 0.001). There was no phrenic nerve injury in Group I, while there were 13 patients who suffered phrenic nerve injury in Group II (p < 0.001). No early mortality in Group I, while five patients died prior to discharge in Group II. Eleven patients underwent diaphragm plication in Group II (p = 0.001). The mean number of hours on the ventilator was significantly higher in Group II (137.3 ± 324.9) compared to Group I (17 ± 66.9), p < 0.001. Group II had a significantly longer length of ICU and hospital stays compared to Group I (p = 0.007 and p = 0.006 respectively).

CONCLUSION

Phrenic nerve injury in children continues to be associated with significant morbidities and increased length of stay. The use of intraoperative phrenic nerve stimulator can be an effective way to localize the phrenic nerve and avoid its injury.

A porcine model of postoperative hemi-diaphragmatic paresis to evaluate a unilateral diaphragmatic pacemaker

Unilateral phrenic nerve damage is a dreaded complication in congenital heart surgery. It has deleterious effects in neonates and children with uni-ventricular circulation. Diaphragmatic palsy, caused by phrenic nerve damage, impairs respiratory function, especially in new-borns, because their respiration depends on diaphragmatic contractions. Furthermore, Fontan patients with passive pulmonary perfusion are seriously affected by phrenic nerve injury, because diaphragmatic contraction augments pulmonary blood flow. Diaphragmatic plication is currently employed to ameliorate the negative effects of diaphragmatic palsy on pulmonary perfusion and respiratory mechanics. This procedure attenuates pulmonary compression by the abdominal contents. However, there is no contraction of the plicated diaphragm and consequently no contribution to the pulmonary blood flow. Hence, we developed a porcine model of unilateral diaphragmatic palsy in order to evaluate a diaphragmatic pacemaker. Our illustrated step-by-step description of the model generation enables others to replicate and use our model for future studies. Thereby, it might contribute to investigation and advancement of potential improvements for these patients.

Diagnostic Utility of Point-of-Care Ultrasound in the Pediatric Cardiac Intensive Care Unit

Purpose of Review

Recent Findings

Summary

Supplementary Information

Management of phrenic nerve injury post-cardiac surgery in the paediatric patient

BACKGROUND

Phrenic nerve injury is a common complication of cardiac and thoracic surgical procedures, with potentially severe effects on the health of a child. This review aims to summarise the available literature on the diagnosis and management of PNI post-cardiac surgery in paediatric patients with CHD.

MAIN BODY

The presence of injury post-surgery can be difficult to detect and may present with non-specific symptoms, emphasising the importance of an effective diagnostic strategy. Chest X-ray is usually the first investigation for a suspected diagnosis of PNI, which is usually confirmed using fluoroscopy, ultrasound scan, or phrenic nerve stimulation (gold standard). Management options include supportive ventilation and/or invasive diaphragmatic plication surgery. While the optimal timing of plication surgery remains controversial, it is now the most widely accepted treatment for PNI in children post-CHD surgery, especially for very young patients who cannot be weaned off supportive ventilation. Further research is needed to determine the optimal timing of surgical intervention for positive outcomes and to explore the benefits of using minimally invasive surgical techniques in children.

CONCLUSION

PNI is a common and serious complication of CHD surgery, therefore, its diagnosis and management in the paediatric population are of major importance. Further research is needed to determine the optimal timing of surgical intervention for positive outcomes and to explore the benefits of using minimally invasive surgical techniques in children.

Outcome analysis of a conservative approach to diaphragmatic paralysis following congenital cardiac surgery in neonates and infants: a bicentric retrospective study

 

OBJECTIVES

Diaphragmatic paralysis following congenital cardiac surgery is associated with significant morbidity and mortality. Spontaneous recovery of diaphragmatic function has been described, contrasting with centres providing early diaphragmatic plication. We aimed to describe the outcomes of a conservative approach, as well as to identify factors associated with a failure of the strategy.

METHODS

This is a retrospective study of patients admitted after cardiac surgery and suffering unilateral diaphragmatic paralysis within 2 French Paediatric Cardiac Surgery Centers. The conservative approach, defined by the prolonged use of ventilation until successful weaning from respiratory support, was the primary strategy adopted in both centres. In case of unsuccessful evolution, a diaphragmatic plication was scheduled. Total ventilation time included invasive and non-invasive ventilation. Diaphragm asymmetry was defined by the number of posterior rib segments counted between the 2 hemi-diaphragms on the chest X-ray after cardiac surgery.

RESULTS

Fifty-one neonates and infants were included in the analysis. Patients' median age was 12.0 days at cardiac surgery (5.0-82.0), and median weight was 3.5 kg (2.8-4.9). The conservative approach was successful for 32/51 patients (63%), whereas 19/51 patients (37%) needed diaphragm plication. There was no difference in patients' characteristics between groups. Respiratory support prolonged for 21 days or more and diaphragm asymmetry more than 2 rib segments were independently associated with the failure of the conservative strategy [odds ratio (OR) 6.9 (1.29-37.3); P = 0.024 and OR 6.0 (1.4-24.7); P = 0.013, respectively].

CONCLUSIONS

The conservative approach was successful for 63% of the patients. We identified risk factors associated with the strategy's failure.

Early diagnosis of diaphragm palsy after pediatric cardiac surgery and outcome after diaphragm plication - A single-center experience

Objective :

The aims of our prospective observational study were to evaluate the (1) reliability of clinical signs in the early detection of diaphragm palsy (DP); (2) reliability of ultrasonography using echo machine as a bedside tool for the diagnosis of DP; and (3) does early diaphragm plication result in the improved outcome? We also sought to determine the incidence and predominant risk factors for DP and diaphragm plication at our center.

Materials and Methods :

This prospective observational study included patients with suspected DP from January 2015 to December 2018. Patients with suspected DP were initially evaluated by bedside ultrasonography using echo machine and confirmed by fluoroscopy. Diaphragm plication was considered for patients having respiratory distress, difficult weaning, or failed extubation attempt without any obvious cardiac or pulmonary etiology. Patients were followed for 3 months after discharge to assess diaphragm function.

Results:

A total of 87 patients were suspected of DP based on clinical signs. DP was diagnosed in 61 patients on fluoroscopy. The median time from index operation to diagnosis was 10 (1–59) days. Diaphragm plication was done among 52 patients and not done in nine patients. Bedside ultrasonography using echo machine was 96.7% sensitive and 96.15% specific in diagnosing DP. Early plication (<14 days) significantly reduced the need for nasal continuous positive airway pressure (65% vs. 96%, P = 0.02), duration of mechanical ventilation (12 vs. 25 days, P = 0.018), intensive care unit (ICU) stay (25 days vs. 39 days, P = 0.019), and hospital stay (30 days vs. 46 days, P = 0.036).

Conclusion :

Hoover's sign and raised hemidiaphragm on chest X-ray are the most specific clinical signs to suspect unilateral DP. Bedside ultrasonography using an echo machine is a good diagnostic investigation comparable to fluoroscopy. Early plication facilitates weaning from the ventilator and thereby decreases the ICU stay and hospital stay.

Diaphragm Paralysis After Pediatric Cardiac Surgery: An STS Congenital Heart Surgery Database Study

BACKGROUND

Previous single-center studies of diaphragm paralysis (DP) after pediatric cardiac surgery report incidence of 0.3% to 12.8% and associate DP with respiratory complications, prolonged ventilation and length of stay, and mortality. To better define incidence and associations between DP and various procedures and outcomes, we performed a multicenter study.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database was queried to identify children who experienced DP after cardiac surgery (2010-2018; 126 centers). Baseline characteristics and postoperative outcomes were compared between patients with and without DP as well as between patients who underwent plication and those who did not. Associations between center volume and center rates of DP and use of plication were also explored.

RESULTS

A total of 2214 of 191,463 (1.2%) patients experienced DP. Postoperative DP portended worse outcomes, including mortality (5.6% vs 3.5%; P < .001), major morbidity (37.2% vs 10.7%; P < .001), tracheostomy (7.1% vs 0.9%; P < .001), prolonged mechanical ventilation (38.0% vs 7.8%; P < .001), and 30-day readmission (22.0% vs 10.6%; P < .001). A total of 1105 of 2214 (49.9%) patients with DP underwent plication. Patients who underwent plication were younger, were smaller, had more risk factors, and underwent more complex surgeries. Plication rates varied widely across centers. There was no correlation between center volume and center risk-adjusted rates of DP (r = .05, P = .5), nor frequency of plication (r = .08, P = .4).

CONCLUSIONS

DP complicating pediatric heart surgery is rare but portends significantly worse outcomes. One-half of patients underwent plication. Center-level risk-adjusted rates of DP and plication are not associated with case volume. Significant variability in plication practices suggests a target for quality improvement.

Unilateral diaphragmatic paralysis associated with surgical mitral valve repair in dogs

OBJECTIVES

Unilateral diaphragmatic paralysis (UDP) due to phrenic nerve injury is a potential complication of thoracic surgery. This study evaluated the prevalence of UDP associated with surgical mitral valve repair (MVR) and its effect on surgical outcomes in dogs.

ANIMALS, MATERIALS AND METHODS

Two hundred ninety-four dogs that underwent MVR were included in the study. A retrospective review of medical records was performed for dogs surviving surgery. Diagnosis of UDP was based on preoperative and postoperative thoracic dorsoventral radiographs.

RESULTS

A total of 284 dogs survived until the day after surgery. The prevalence of UDP on the day after surgery, on the day of discharge, and after the first postoperative month was 30%, 24%, and 9%, respectively. One case of UDP was observed at 3 months after surgery. Unilateral diaphragmatic paralysis was exhibited by nine of the 21 patients that died in the hospital. The proportion of patients with UDP was higher in dogs that died of respiratory failure than in dogs that died of other causes (p = 0.002). Most dogs whose deaths were suspected to have been related to respiratory failure also had pre-existing respiratory diseases. The occurrence of UDP did not relate to the lengths of stay in the intensive care unit or the hospital.

CONCLUSIONS

Our findings suggest that UDP is a common complication in dogs after MVR and that the prevalence of UDP decreases with time after surgery. Unilateral diaphragmatic paralysis is a risk factor for postoperative death, especially in patients with pre-existing respiratory disease.

Thoracic versus abdominal approach to correct diaphragmatic eventration in children

BACKGROUND

Plication of diaphragm (DP) for eventration (DE) can be done using thoracic or abdominal approaches. The purpose of our study was to compare outcomes between these approaches based on our experience and on systematic literature review.

METHODS

Retrospective records of children <16 years who underwent DP (single-center, 2004-2018) were recorded and analyzed. Systematic review and meta-analysis of related studies was undertaken. Data are reported as median (range).

RESULTS

Eighty-nine cases were identified in thoracic (Congenital = 5, Acquired = 84) and 13 (Congenital = 10, Acquired = 3) in abdominal group aged 5.88 (0.36-184.44) and 10.0 (0.12-181.8) months. Improvement in diaphragm level post-DP was significantly higher in abdominal [2(0-4)] than chest [1.5(0-5)] group (p = 0.04). On Cox regression analysis, there was a non-significant trend to a longer time to extubation in the chest group (Hazard ratio (HR) = 0.539[0.208-1.395], p = 0.203). Patients operated transthoracically left intensive care unit after a significantly longer time (HR = 0.339[0.119-0.966], p = 0.043). Patients operated transabdominally tended to be fed later, although this was not significant (HR = 1.801[0.762-4.253], p = 0.043). On Kaplan-Meier analysis, there was a non-significant trend to a lower rate of recurrence in the abdominal group (HR = 0.3196[0.061-1.675], p = 0.1876). In the meta-analysis including three published studies as well as our data (total n = 181, Thoracic = 139, Abdominal = 42), no difference was found in the incidence of recurrence amongst the 2 groups (RD = -0.04, 95%CI = -0.25, 0.18, p = 0.74).

CONCLUSION

This is one of the largest reports on outcomes of children undergoing DP for DE. There is no significant difference in recurrence rate, even though all recurrences in our series (15.7%) were in the acquired cases operated using a thoracic approach.

TYPE OF STUDY

Treatment Retrospective Comparative Study.

LEVEL OF EVIDENCE

Level III.

Impact of Phrenic Nerve Palsy on Late Fontan Circulation

BACKGROUND

Although adverse effects of phrenic nerve palsy (PNP) on early Fontan circulation have been reported, detailed late impact remains unclear.

METHODS

Of 218 patients undergoing extracardiac total cavopulmonary connection between 1995 and 2008, 160 who all underwent cardiac catheter examination, spirometry, and exercise capacity testing 10 years after the operation were enrolled. The cohort was divided into 2 groups: with (N = 21) or without PNP (control group, N = 139). The patients with PNP were further divided into the recovered PNP group (n = 10) and the persistent PNP group (n = 11). All but 2 patients who developed PNP (90.9%) underwent diaphragmatic plication. There was no difference in hemodynamic indices at pre-Fontan evaluation among the three groups.

RESULTS

Ten years after the Fontan procedure, the averaged forced vital capacity was 81% ± 18% of predicted in the control group, 86% ± 17% in the recovered PNP group, and 56% ± 12% in the persistent PNP group (P < .001). Peak oxygen consumption was linearly correlated to the forced vital capacity (r = 0.222, P = .009). There was no significant difference in the peak oxygen consumption between groups. Significant veno-venous collaterals into the diaphragm from lower body to pulmonary vein(s) or atria more frequently developed in patients who underwent diaphragmatic plication compared with those who did not (P < .001).

CONCLUSIONS

Persistent PNP resulted in reduced forced vital capacity; however, its influence on exercise intolerance could not be identified. Diaphragmatic plication should be reserved for patients who experience clinically significant respiratory or hemodynamic sequelae of PNP.

Correlation between the dimensions of diaphragm movement, respiratory functions and pressures in accordance with the gross motor function classification system levels in children with cerebral palsy

This study was executed as correlation study to investigate the correlation between the dimensions of diaphragm movement, and respiratory functions and pressures in accordance with the Gross Motor Function Classification System (GMFCS) levels on children with cerebral palsy as the participants. Forty-three children in the age range of 5–13 years diagnosed with cerebral palsy as the research participants were divided into three groups (levels I, II, and III) through systematic stratified random sampling in accordance with their GMFCS levels. Pearson correlation analysis was executed to examine the correlation between dimensions of diaphragm movement, and respiratory functions and pressures in accordance with the GMFCS levels of the participants. There was no significant correlation between the dimensions of diaphragm movement, and respiratory functions and pressures in all of the three groups in accordance with the GMFCS levels of the participants. Therefore, it is deemed that although measurement of the dimensions of diaphragm movement of children with cerebral palsy by using diagnostic ultrasonic M-mode imaging device can be considered as auxiliary tool in predicting the breathing capabilities, it cannot be used as independent measurement equipment.

Management of phrenic nerve palsy following cardiac surgery

Phrenic nerve palsy (PNP) is a potential complication of cardiac surgery. It may prolong ventilation and hospitalization and result in significant morbidity and mortality. The diagnosis and management of PNP following cardiac surgery is reviewed.

Impact of Phrenic Nerve Palsy and Need for Diaphragm Plication Following Surgery for Pulmonary Atresia With Ventricular Septal Defect and Major Aortopulmonary Collaterals

Injury to the phrenic nerves may occur during surgery for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA-VSD and MAPCAs). These patients may develop respiratory failure and require diaphragm plication. The purpose of this study was to evaluate the impact of phrenic nerve palsy on recovery following surgery for PA-VSD and MAPCAs. Between 2007 and 2016, approximately 500 patients underwent surgery for PA-VSD and MAPCAs at our institution. Twenty-four patients (4.8%) subsequently had evidence of new phrenic nerve palsy. Sixteen patients were undergoing their first surgical procedure, whereas 8 were undergoing reoperations. All 24 patients underwent diaphragm plication. A cohort of matched controls was identified based on identical diagnosis and procedures but did not sustain a phrenic nerve palsy. Eighteen of the 24 patients (75%) had clinical improvement following diaphragm plication as evidenced by the ability to undergo successful extubation (5 ± 2 days), transition out of the intensive care unit (32 ± 16 days), and discharge from the hospital (42 ± 19 days). In contrast, there were 6 patients (25%) who did not demonstrate a temporal improvement following diaphragm plication, as evidenced by intervals of 61 ± 38, 106 ± 45, and 108 ± 46 days, respectively (P < 0.05 for all 3 comparisons). The 6 patients who failed to improve following diaphragm plication had a significantly greater number of comorbidities compared to the 18 patients who demonstrated improvement (2.2 vs 0.6 per patient, P < 0.05). When compared with the control group, patients who improved following diaphragm plication spent an additional 22 days and patients who failed to improve an additional 90 days in the hospital. The data demonstrate a bifurcation of clinical outcome in patients undergoing diaphragm plication following surgery for PA-VSD and MAPCAs. This bifurcation appears to be linked to the presence or absence of other comorbidities.

Bilateral Diaphragmatic Paralysis Following Paediatric Cardiac Surgery: Experience of four cases at the Royal Hospital, Muscat, Oman

Bilateral diaphragmatic paralysis (BDP) is a rare complication of paediatric cardiac surgery. We report four children who developed BDP following cardiac surgery who were managed at the Royal Hospital, Muscat, Oman, between 2009 and 2014. All four children suffered severe respiratory distress soon after extubation and required re-intubation within two hours. In addition, all of the children underwent a tracheostomy as an interim method for ventilation. The four children were successfully weaned from positive pressure ventilation following the functional recovery of at least one side of the diaphragm.

The advantage of early plication in children diagnosed with diaphragm paresis

BACKGROUND

In this single-center study, we sought to determine the frequency of phrenic nerve injury leading to diaphragm paresis (DP) in children following open cardiac surgery over the last 10 years, and to identify possible variables that predict the need for plication and associated clinical outcomes.

METHODS

Patients diagnosed with DP were identified from departmental databases and a review of clinical diaphragm ultrasound images. A cohort was analyzed for predictors of diaphragm plication and associations with clinical outcomes. Cumulative proportion graphs modeled the association between plication and length of stay.

RESULTS

DP was diagnosed in 161 of 6448 patients (2.5%) seen between January 2002 and December 2012. All diagnoses but 1 were confirmed by ultrasound. Plication of the diaphragm was performed in 30 patients (19%); compared with patients who did not undergo plication, these patients were younger (median age, 10 days vs 138 days; P < .001), more likely to have undergone deep hypothermic circulatory arrest (47% vs 18%; P = .005), had a longer duration of positive pressure ventilation (median, 15 days vs 7 days; P < .001), and had longer lengths of stay in both the intensive care unit (median, 23 days vs 8 days; P < .0001) and the hospital (median, 37 days vs 15 days; P < .0001). Early plication was associated with reduction in all intervals of care.

CONCLUSIONS

Early plication should be considered for patients with diaphragm paresis requiring prolonged respiratory support after cardiac bypass surgery. Longer follow-up evaluation is required to better define the long-term implications of plication.

A ferromagnetic surgical system reduces phrenic nerve injury in redo congenital cardiac surgery

A ferromagnetic surgical system (FMwand®) is a new type of dissection device expected to reduce the risk of adjacent tissue damage. We reviewed 426 congenital cardiac operations with cardiopulmonary bypass through redo sternotomy to assess if this device prevented phrenic nerve injury. The ferromagnetic surgical system was used in 203 operations (47.7%) with regular electrocautery and scissors. The preoperative and operative details were similar between the operations with or without the ferromagnetic surgical system. The incidence of phrenic nerve injury was significantly lower with the ferromagnetic surgical system (0% vs 2.7%, P = 0.031). A logistic regression model showed that the use of the ferromagnetic surgical system was significantly associated with reduced odds of phrenic nerve injury (P < 0.001).

Bedside Ultrasound for the Diagnosis of Abnormal Diaphragmatic Motion in Children After Heart Surgery

OBJECTIVE

To assess the utility of bedside ultrasound combining B- and M-mode in the diagnosis of abnormal diaphragmatic motion in children after heart surgery.

DESIGN

Prospective post hoc blinded comparison of ultrasound performed by two different intensivists and fluoroscopy results with electromyography.

SETTING

Tertiary university hospital.

SUBJECTS

Children with suspected abnormal diaphragmatic motion after heart surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Abnormal diaphragmatic motion was suspected in 26 children. Electromyography confirmed the diagnosis in 20 of 24 children (83.3%). The overall occurrence rate of abnormal diaphragmatic motion during the study period was 7.5%. Median patient age was 5 months (range, 16 d to 14 yr). Sensitivity and specificity of chest ultrasound performed at the bedside by the two intensivists (91% and 92% and 92% and 95%, respectively) were higher than those obtained by fluoroscopy (87% and 83%). Interobserver agreement (k) between both intensivists was 0.957 (95% CI, 0.87-100).

CONCLUSIONS

Chest ultrasound performed by intensivists is a valid tool for the diagnosis of diaphragmatic paralysis, presenting greater sensitivity and specificity than fluoroscopy. Chest ultrasound should be routinely used after pediatric heart surgery given its reliability, reproducibility, availability, and safety.

Bilateral diaphragmatic palsy after congenital heart surgery: management options

Diaphragmatic paralysis following phrenic nerve injury is a major complication following congenital cardiac surgery. In contrast to unilateral paralysis, patients with bilateral diaphragmatic paralysis present a higher risk group, require different management methods, and have poorer prognosis. We retrospectively analysed seven patients who had bilateral diaphragmatic paralysis following congenital heart surgery during the period from July, 2006 to July, 2014. Considerations were given to the time to diagnosis of diaphragm paralysis, total ventilator days, interval after plication, and lengths of ICU and hospital stays. The incidence of bilateral diaphragmatic paralysis was 0.68% with a median age of 2 months (0.6-12 months). There was one neonate and six infants with a median weight of 4 kg (3-7 kg); five patients underwent unilateral plication of the paradoxical diaphragm following recovery of the other side, whereas the remaining two patients who did not demonstrate a paradoxical movement were successfully weaned from the ventilator following recovery of function in one of the diaphragms. The median ventilation time for the whole group was 48 days (20-90 days). The median length of ICU stay was 46 days (24-110 days), and the median length of hospital stay was 50 days (30-116 days). None of the patients required tracheostomy for respiratory support and there were no mortalities, although all the patients except one developed ventilator-associated pneumonia. The outcome of different management options for bilateral diaphragmatic paralysis following surgery for CHD is discussed.

Thoracoscopic plication for diaphragmatic eventration after surgery for congenital heart disease in children

OBJECTIVE

The aim of this study was to clarify the role of thoracoscopic plication for diaphragmatic eventration after surgery for congenital heart disease (CHD) in children.

PATIENTS AND METHODS

We retrospectively reviewed the medical charts of pediatric patients who had undergone thoracoscopic plication of diaphragmatic eventration after surgery for CHD between 2008 and 2013 at our department.

RESULTS

Five patients were identified during the study period. The median age and body weight of the patients were 7.6 months and 6.6 kg, respectively. The associated CHDs were pulmonary artery atresia in 3 patients, truncus arteriosus in 1 patient, and double-outlet right ventricle in 1 patient. Four patients needed preoperative mechanical respiratory support. At operation, all the patients received CO2 insufflation (4 mm Hg), and single-lung ventilation was attempted in 3 patients using a bronchial blocker. A sufficient operative field was maintained by CO2 insufflation in all the patients regardless of single-lung ventilation. The procedure was not converted to open operation in any patient. Postoperative extubation was performed in the operating room in 1 patient, on the day of operation in 2 patients, and on postoperative Days 1 and 2 in 2 patients. Air embolism was not observed in any of the patients. Diaphragmatic eventration did not recur in any of the patients after thoracoscopic plication.

CONCLUSIONS

Thoracoscopic plication is a safe and effective procedure for pediatric diaphragmatic eventration after surgery for CHD. Considering the sufficient operative field maintained by CO2 insufflation, single-lung ventilation using a bronchial blocker would be unnecessary for this procedure. With its safety and good outcome, early thoracoscopic plication is a good treatment option for pediatric patients with symptomatic diaphragmatic eventration after surgery for CHD.

Pediatric lung transplantation: promise being realized

PURPOSE OF REVIEW

Lung transplantation for infants and children is an accepted but rarely exercised option for the treatment of end-stage lung disease, with outcomes equivalent to those for adults. However, widespread misconceptions regarding pediatric outcomes often confound timely and appropriate referral to specialty centers. We present the updated information for primary pediatricians to utilize when counseling families with children confronted by progressive end-stage pulmonary or cardiovascular disease.

RECENT FINDINGS

We provide general guidelines to consider for referral, and discuss allocation of organs in children, information regarding standard treatment protocols, and survival outcomes.

SUMMARY

Lung transplantation is a worthwhile treatment option to consider in children with end-stage lung disease. The treatment is complex, but lung transplant provides substantial survival benefit and markedly improved quality of life for children and their families. This timely review provides comprehensive information for pediatricians who are considering options for treatment of children with end-stage lung disease.

Is video-assisted thoracoscopic diaphragmatic plication a widespread technique for diaphragmatic hernia in adults? Review of the literature and results of a national survey

Diaphragmatic plication is the most accepted treatment for symptomatic diaphragmatic hernia in adults. The fact that this pathology is infrequent and this procedure not been widespread means that this is an exceptional technique in our field. To estimate its use in the literature, we carried out a review in English and Spanish, to which we added our series. We found only six series that contribute 59 video-assisted mini-thoractomy for diaphragmatic plications in adults, and none in Spanish. Our series will be the second largest with 18 cases. Finally, we conducted a survey in all the Spanish Thoracic Surgery units in Spain: none reported more than 10 cases operated by thoracoscopy in the last 8 years (except our series) and most continue employing thoracotomy as the main approach. We believe that many patients with symptomatic diaphragmatic hernia could benefit from the use of such techniques.

One hundred useful references in pediatric cardiac intensive care: the 2012 update

OBJECTIVE

The specialty of pediatric cardiac critical care has undergone rapid scientific and clinical growth in the last 25 years. The Board of Directors of the Pediatric Cardiac Intensive Care Society assembled an updated list of sentinel references focused on the critical care of children with congenital and acquired heart disease. We encouraged board members to select articles that have influenced and informed their current practice or helped to establish the standard of care. The objective of this article is to provide clinicians with a compilation and brief summary of these updated 100 useful references.

DATA SOURCES

The list of 'One Hundred Useful References for Pediatric Cardiac Intensive Care' (2004) and relevant literature to the practice of cardiac intensive care.

DATA SELECTION

A subset of Pediatric Cardiac Intensive Care Society board members compiled the initial list of useful references in 2004, which served as the basis of the new updated list. Suggestions for relevant articles were submitted by the Pediatric Cardiac Intensive Care Society board members and selected pediatric cardiac intensivists with an interest in this project following the Society's meeting in 2010. Articles were considered for inclusion if they were named in the original list from 2004 or were suggested by Pediatric Cardiac Intensive Care Society board members and published before December 31, 2011.

DATA EXTRACTION

Following submission of the complete list by the Pediatric Cardiac Intensive Care Society board and contributing Society members, articles were complied by the two co-first authors (D.A., D.K.). The authors also performed Medline searches to ensure comprehensive inclusion of all relevant articles. The final list was then submitted to the Pediatric Cardiac Intensive Care Society board members, who ranked each publication.

DATA SYNTHESIS

Rankings were compiled and the top 100 articles with the highest scores were selected for inclusion in this publication. The two co-first authors (D.A., D.K.) reviewed all existing summaries and developed summaries of the newly submitted articles.

CONCLUSIONS

An updated compilation of 100 useful references for the critical care of children with congenital and acquired heart disease has been compiled and summarized here. Clinicians and trainees may wish to use this document as a reference for education in this complex and challenging subspecialty.

Airway Management following Pediatric Cardiothoracic Surgery

Objectives

(1) Review airway management in pediatric patients undergoing cardiothoracic surgery (CTS); (2) determine the incidence of airway-related complications of CTS in this population.

Design

Case series with chart review.

Setting

Tertiary care children’s hospital.

Patients

Children undergoing CTS over a 4-year period.

Methods

Patients who underwent CTS at a single, tertiary care, children’s hospital between June 1, 2007, and May 31, 2011, were retrospectively reviewed; those <18 years who had open CTS were included. Statistical analysis examined relationships of intubation duration, complications, and need for tracheotomy while comparing patient characteristics, comorbidities, and types of surgery.

Results

Eight hundred seventy-five primary surgeries in 745 patients met inclusion criteria. Mean postoperative intubation duration was 7.2 days and median 3 days. On univariate analysis, significantly longer postoperative intubation requirements were found in patients younger in age, with congenital comorbidities or prematurity, with preoperative ventilation requirements, and those with early postoperative complications. Multivariate analysis found younger age, presence of congenital comorbidities, preoperative intubation requirements, and early postoperative complications each lengthen ventilation requirements. Four patients developed vocal cord paralysis and 5 developed phrenic nerve palsy. Nineteen patients required tracheotomy.

Conclusions

In this large cohort, CTS in the pediatric population is associated with few long-term or permanent airway-related complications. Patients who are younger in age and those with congenital comorbidities, preoperative ventilation requirements, or early postoperative complications required longer periods of postoperative intubation.

Early hemi-diaphragmatic plication through a video assisted mini-thoracotomy in postcardiotomy phrenic nerve paresis

New symptom onset of respiratory distress without other cause, and new hemi-diaphragmatic elevation on chest radiography postcardiotomy, are usually adequate for the diagnosis of phrenic nerve paresis. The symptom severity varies (asymptomatic state to severe respiratory failure) depending on the degree of the lesion (paresis vs. paralysis), the laterality (unilateral or bilateral), the age, and the co-morbidity (respiratory, cardiac disease, morbid obesity, etc). Surgical treatment (hemi-diaphragmatic plication) is indicated only in the presence of symptoms. The established surgical treatment is plication of the affected hemidiaphragm which is generally considered safe and effective. Several techniques and approaches are employed for diaphragmatic plication (thoracotomy, video-assisted thoracoscopic surgery, video-assisted mini-thoracotomy, laparoscopic surgery). The timing of surgery depends on the severity and the progression of symptoms. In infants and young children with postcardiotomy phrenic nerve paresis the clinical status is usually severe (failure to wean from mechanical ventilation), and early plication is indicated. Adults with postcardiotomy phrenic nerve paresis usually suffer from chronic dyspnoea, and, in the absence of respiratory distress, conservative treatment is recommended for 6 months -2 years, since improvement is often observed. Nevertheless, earlier surgical treatment may be indicated in non-resolving respiratory failure. We present early (25(th) day postcardiotomy) right hemi-diaphragm plication, through a video assisted mini-thoracotomy in a high risk patient with postcardiotomy phrenic nerve paresis and respiratory distress. Early surgery with minimal surgical trauma, short operative time, minimal blood loss and postoperative pain, led to fast rehabilitation and avoidance of prolonged hospitalization complications. The relevant literature is discussed.

Diaphragmatic Nerve Palsy After Cardiac Surgery in Children in Egypt

Introduction: Diaphragmatic paralysis (DP) due to phrenic nerve injury is a complication which occurs in association with congenital cardiac surgery and may be a life-threatening event in infants and young children. Information about this complication is still scarce from the developing countries. Methods: Retrospective study evaluated the incidence of DP among 414 patients who underwent congenital cardiac surgery in Abo Elriesh Children’s Specialized Hospital, Cairo University, Egypt, in the duration from April 2009 to December 2011. Results: Incidence of DP was 3.6% (15 of 414 cases). Median age of affected patients was 10 months (ranged from 1 month to 13 years). Diagnosis of DP was observed after ventricular septal defect repair (3.9%), Glenn anastomosis (8.6%), Tetralogy of Fallot repair (4.3%), Senning operation (10%), arterial switch operation (3.2%), Fontan procedure (33%), coarctation of the aorta repair (7%), and pulmonary artery banding (6.4%). Diaphragmatic plication was performed in 4 of 15 cases. Patients with DP had significantly prolonged mechanical ventilation duration as compared to unaffected patients (median 120, range 48-600 vs 4, range 0-48 hours, P < .000). They also had a higher incidence of nosocomial pneumonia in 8 of 15 (53%) cases, longer duration of intensive care unit stay (median 15, range 4-62 days, P < .006), and significant mortality in 7 of 15 (46%; P < .004). Mortality among patients who underwent diaphragm plication was 1 of 4 (25%). Conclusion: Diaphragmatic paralysis is a relatively rare complication of congenital cardiac surgery in children. Its occurrence is associated with increased morbidity and mortality. A high index of clinical suspicion, utilization of bedside diagnostic tools, and a policy of early plication for certain patients may lead to improved outcomes.

Diaphragmatic paralysis among very low birth weight infants following ligation for patent ductus arteriosus

Management of diaphragmatic paralysis (DP) among newborn infants remains controversial, especially for very low birth weight (VLBW) infants following ligation for patent ductus arteriosus (PDA). This study aimed to characterize the impact of DP after PDA ligation among VLBW infants. Clinical characteristics of DP cases treated with either diaphragmatic plication or conservative methods were described as well. The medical records of VLBW infants who underwent PDA ligation in Chang Gung Memorial Hospital between January 2000 and December 2011 were retrospectively reviewed, and DP was suspected if postligation chest X-rays showed an elevation of the left diaphragm as confirmed by a chest ultrasonograph. For each DP case, three other infants that received PDA ligation with proximate birth dates and who were closely matched in terms of gestational age (±1 week) and birth weight (±10 %) were selected as the control group. A total of eight preterm infants were diagnosed as having DP and 24 infants were selected as the control group. The affected infants usually presented with respiratory distress and extubation failure. The study demonstrated that, among our patient population, DP was associated with a significantly longer duration of ventilator dependency (56.1 ± 16.0 vs. 29.8 ± 17.7 days, p = 0.001) and a higher incidence of severe bronchopulmonary dysplasia (87.5 vs. 23 %, p = 0.002). For selective infants with DP-related ventilatory failure after PDA ligation, surgical plication may facilitate extubation. Diaphragmatic paralysis should be evaluated carefully among VLBW infants receiving PDA ligation because of its adverse impact on ventilator dependency and correlation to a higher incidence of severe bronchopulmonary dysplasia.

Diaphragmatic palsy after cardiac surgical procedures in patients with congenital heart

Paralysis of diaphragm on one or, exceptionally, both sides is a common cause of delayed recovery and excessive morbidity following pediatric cardiac surgery. The consequences of this complication after all forms of congenital heart surgery in newborns and young infants can be potentially serious. The impact of diaphragmatic palsy on the physiology after single ventricle palliations is particularly significant. It is necessary for all professionals taking care of children with heart disease to be familiar with the etiology, diagnosis, and management of this condition. Early recognition and prompt management of diaphragmatic palsy can potentially reduce the duration of mechanical ventilation and intensive care in those who develop this complication. This review summarizes the anatomy of the phrenic nerves, reasons behind the occurrence of diaphragmatic palsy, and suggests practical guidelines for management.

Perioperative factors associated with prolonged mechanical ventilation after complex congenital heart surgery

OBJECTIVE

To evaluate perioperative factors associated with prolonged mechanical ventilation in children undergoing complex cardiac surgery for congenital heart disease.

DESIGN

Retrospective chart review.

SETTING

A tertiary care pediatric cardiac intensive care.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

This retrospective cohort study included all patients undergoing complex cardiac surgical procedures (Risk Adjustment in Congenital Heart Surgery-1 category ≥ 3) at our institution during 2003. We defined prolonged mechanical ventilation as need for mechanical ventilation for ≥ 7 days (90th percentile of duration of mechanical ventilation for the whole cohort). Multivariate logistic regression analyses were used to determine independent relationships between perioperative factors and prolonged mechanical ventilation. A total of 362 patients were admitted to the cardiac intensive care unit after a cardiac surgical procedure of Risk Adjustment in Congenital Heart Surgery-1 ≥ 3 level of complexity and survived to hospital discharge. Median age was 242 days (range, 4 days-14.4 yrs), the median duration of mechanical ventilation was 1.5 days (range, 0-7 days), and 41 patients (11%) were ventilated for ≥ 7 days. Age of <30 days at surgery, higher Pediatric Risk of Mortality III score at the time of cardiac intensive care unit admission, the presence of major noncardiac structural anomalies, healthcare-associated infections, noninfectious pulmonary complications (pleural effusions and pneumothorax), and the need for reintervention were all independently associated with prolonged mechanical ventilation.

CONCLUSIONS

Younger age, greater severity of illness at postoperative admission, healthcare-associated infections, noninfectious pulmonary complications, and the need for reintervention are associated with prolonged mechanical ventilation after complex cardiac surgery. Future studies and quality improvement initiatives should focus on those risk factors that are modifiable to promote early extubation in children recovering from complex congenital heart surgery.

Diaphragmatic paralysis after pediatric heart surgery: usefulness of non-invasive ventilation

Diaphragmatic paralysis after cardiac surgery is an important complication especially in infants. We report a child who developed diaphragmatic paralysis, atelectasis, bronchomalasia and respiratory failure following cardiac surgery. Ventilatory support alleviated respiratory distress in this child. This report illustrates the usefulness of invasive and non-invasive ventilatory support for a pediatric patient with diaphragmatic paralysis.

Phrenic nerve palsy in children associated with confirmed intrathoracic tuberculosis: diagnosis and clinical course

In this descriptive retrospective cases series of eight cases phrenic nerve palsy in children caused by tuberculosis lymph gland infiltration of the phrenic nerve. The lymph gland enlargement was in all cases caused by culture confirmed Mycobacterium tuberculosis. The phrenic nerve palsy was on the left side in all eight cases with the presenting feature a raised diaphragm on chest radiography that was accompanied by consolidation of the left upper lobe (88%) The diagnosis of phrenic nerve palsy was confirmed by fluoroscopy of the chest. On computer tomography the outstanding features were left sided hilar and paratracheal lymph gland enlargement with displacement of the mediastinum to the right. Mediastinal displacement lead to anterior displacement of the descending aorta, which further compressed the left main bronchus. Two children had accompanying respiratory failure requiring assisted ventilation and in two additional cases the airway compression was so severe that glandular enucleation of the enlarged glands was indicated. Of the eight children five remained symptomatic after completion of TB treatment to which steroids were added for the initial month. Diaphragmatic plication was indicated in all five cases. On clinical follow-up two children had repeated respiratory tract infections secondary to underlying lung damage while the other six remained asymptomatic.

Peri-operative management of paediatric patients undergoing cardiac surgery--focus on respiratory aspects of care

Children requiring cardiac surgery present particular challenges in peri-operative respiratory management. The wide variety of conditions and operations and their varied impact on respiratory function makes dialogue with related medical staff essential. In most circumstances, cardiac performance is the main determinant of respiratory outcomes. Changing cardiologic and surgical approaches have combined to diminish the severity and frequency of pulmonary hypertensive issues and new treatment modalities are simplifying the intensive care approach. Patients with Down's syndrome and 22q11 deletion syndrome present particular issues related to anatomy, physiology and respiratory function. Certain conditions, including tetralogy of Fallot and cavopulmonary connections, present unique circumstances where respiratory management, sometimes including extubation, may assist in optimisation of cardiac performance. These and other conditions highlight the complexities of cardiopulmonary interactions. Cardiac performance remains the principal determinant of outcome after paediatric cardiac surgery and has the biggest impact on respiratory function.

Subdiaphragmatic venous hemodynamics in patients with biventricular and Fontan circulation after diaphragm plication

OBJECTIVE

Diaphragm paralysis owing to phrenic nerve injury can result in significant morbidity in children undergoing surgical management of congenital cardiac defects. Diaphragm plication is the accepted therapy for diaphragm paralysis. We have investigated subdiaphragmatic venous hemodynamics in patients with biventricular and Fontan circulation after diaphragm plication.

METHODS

Doppler ultrasound was used to evaluate flows in the hepatic vein, portal vein, and subhepatic inferior vena cava under respiratory monitoring and with a tilt table. Twenty-nine patients with biventricular circulation were studied: 19 with normal diaphragms and 10 after diaphragm plication. Twenty-eight patients with total cavopulmonary connections after the Fontan procedure were also studied: 19 with normal diaphragms and 9 with plicated diaphragms. Inspiratory/expiratory flow ratios in supine and upright positions were calculated to investigate respiratory effects, and upright/supine flow ratios were calculated to assess gravity effects.

RESULTS

In patients with biventricular circulation and normal diaphragms, hepatic venous flow was augmented by inspiration; this effect was reduced in patients with a plicated diaphragm (upright inspiratory/expiratory flow ratios: 2.4 vs 1.4, respectively; P = .01). Portal venous flow was higher during expiration; this effect was lost in patients with a plicated diaphragm (supine inspiratory/expiratory flow ratios: 0.8 and 1.0; P < .05). In Fontan patients with normal diaphragms, hepatic venous flow depended heavily on inspiration. This effect was blunted in patients with a plicated diaphragm (supine inspiratory/expiratory flow ratios: 3.2 vs 2.3; P < .05). Expiratory augmentation of portal flow was absent in Fontan patients with normal diaphragms and reversed in patients a plicated diaphragm (supine inspiratory/expiratory flow ratios: 1.0 vs 1.6; P = .02). Gravity reduced Fontan portal venous flow; having a plicated diaphragm did not alter this effect (upright/supine flow ratios: 0.7 vs 0.7).

CONCLUSIONS

In patients with biventricular and those with Fontan circulation with a paralyzed diaphragm, plication does not completely restore normal subdiaphragmatic venous hemodynamics. In Fontan patients with a plicated diaphragm, important inspiration-derived hepatic venous flow is suppressed, and portal venous flow loses its normal expiratory augmentation. These flow dynamics share similarities with those observed in patients with failing Fontan circulation. This suboptimal splanchnic circulation may contribute to early problems of prolonged pleural effusions and ascites and potentially may promote late Fontan failure. Phrenic nerve injury should consequently be avoided at all costs before or at the time of the Fontan operation.

Mid-term follow-up in patients with diaphragmatic plication after surgery for congenital heart disease

OBJECTIVE

Diaphragmatic palsy (DP) is a rare but severe complication after surgery for congenital heart disease. Transthoracic diaphragmatic plication is an effective means of treatment for those with respiratory impairment due to DP, but little is known about the mid-term effects of diaphragmatic plication.

DESIGN

We performed a study in 24 patients with history of DP. Diaphragm movement was assessed using ultrasound. Patients with DP who were old enough were additionally followed-up with lung function and exercise testing. A group of patients with similar age, diagnoses and operations served as controls.

RESULTS

Ultrasound showed that in the majority of cases with history of DP the paralysed diaphragm was static, independently of whether it was plicated or not. Patients with DP had a more restrictive lung function pattern (VC: 54.3 vs. 76.4% predicted, p<0.001; FEV(1): 58.4 vs. 86.2% predicted, p<0.001) and a lower exercise capacity compared with the control group (peak VO2: 24.5 vs. 31.3 ml/kg/min, p=0.03). Comparing patients with and without plication for DP, only a tendency towards lower lung function values in patients after diaphragmatic plication, but no differences regarding exercise capacity, could be found.

CONCLUSIONS

Our results provide evidence that DP is a serious surgical complication with a reduction in lung function and exercise capacity, even at mid-term follow-up; however, diaphragmatic plication, a useful tool in treating post-surgical DP in children with respiratory impairment, seems to be without mid-term risk in terms of recovery of phrenic nerve function, lung function values, and exercise capacity.

Hybrid approach to surgical correction of tetralogy of Fallot in all patients with functioning Blalock Taussig shunts

BACKGROUND

In total surgical correction of tetralogy of Fallot (TOF) with functioning Blalock Taussig shunts (BTS), shunt take down increased surgical time, bleeding, and might injure phrenic and recurrent laryngeal nerve and thoracic duct.

OBJECTIVES

A routine hybrid approach using transcatheter BTS closure immediately before total surgical correction of TOF in all patients might reduce these problems. We analyze the safety and feasibility of this approach.

METHODS

Transcatheter BTS closure was achieved using single or multiple stainless steel embolization coils, Amplatzer vascular plugs, or duct occluders. When coils were released without control by bioptome forceps, coil migration in larger shunts was prevented by proximal or distal balloon occlusion.

RESULTS

This routine hybrid strategy was followed in 22 consecutive patients aged 1-13 years over 4-year-period and 21 procedures were successful. Among the 16 patients attempted with coils, 13 had successful closure, 2 needed Amplatzer duct occluder devices, and 1 sent for surgical shunt takedown due to acute angulation of the shunt. New Amplatzer vascular plugs were used in six patients. Bioptome was used in six patients and proximal or distal balloon occlusion of flow was used in three patients. Four patients had closure of associated aortopulmonary or chest wall collaterals.

CONCLUSION

Hybrid approach using routine transcatheter closure of all BTS immediately before surgical correction of TOF shunts with coils/plugs/devices is safe, feasible, and reproducible.

Electrophysiologic evaluation of phrenic nerve and diaphragm function after coronary bypass surgery: Prospective study of diabetes and other risk factors

OBJECTIVE

Phrenic neuropathy after coronary artery bypass grafting has been related to various risk factors with conflicting results. The aim of this study was to assess the incidence, characteristics, and clinical consequences of phrenic neuropathy and the influence of diabetes and other risk factors.

METHODS

We conducted an observational, prospective study of parallel groups including 94 consecutive patients subjected to coronary artery bypass grafting, half of them with diabetes and associated polyneuropathy. Electrophysiologic study of phrenic nerve conduction as the reference method, chest radiography, diaphragm ultrasound, and functional respiratory tests were performed 24 to 48 hours before and 7 days after surgery. In those patients showing phrenic neuropathy, explorations were repeated, including needle diaphragmatic electromyography, at 1, 3, 6, 9, 12, 18, and 24 months or until recovery.

RESULTS

Fifteen of the 94 patients (16%) had phrenic neuropathy, 9 in the left side, 3 on the right, and 3 bilateral. Nine (60%) of the affected patients had diabetes, but diabetes did not represent a greater risk of neuropathy (relative risk 1.5, 95% confidence interval 0.6-3.9). Multivariate analysis showed no association of phrenic nerve injury with age, sex, ejection fraction, diabetes, use of internal thoracic artery, or number of grafts as risk factors. Phrenic neuropathy did not result in greater morbidity, and most patients recovered in less than 1 year.

CONCLUSIONS

None of the risk factors studied, including diabetes, influenced the appearance of phrenic neuropathy, thus indicating a role for nerve damage during surgery. Low morbidity and relatively rapid recovery were observed.

Reliability of two-dimensional echocardiography in the assessment of clinically significant abnormal hemidiaphragm motion in pediatric cardiothoracic patients: Comparison with fluoroscopy

OBJECTIVE

To assess the utility and reliability of echocardiographic assessment of hemidiaphragm motion abnormalities in pediatric cardiothoracic patients.

DESIGN

Retrospective observational study, with post hoc blinded assessment of echocardiographic and fluoroscopic results.

SETTING

Tertiary care center.

PATIENTS

Thirty-six consecutive pediatric cardiothoracic patients with suspected hemidiaphragm paralysis were identified and included in the study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The results of both echocardiographic and fluoroscopic studies on all patients were included. In addition, blinded review of study results were performed. The sensitivity and specificity of fluoroscopy in identifying hemidiaphragms that needed plication were 100% and 74%, respectively. The positive predictive value was 55%; negative predictive value was 100%. Comparing reported diagnoses with blinded review of the studies showed poor agreement; reviewers agreed with 89% diagnosed as normal, 44% of paralyzed, and 76% of paradoxical hemidiaphragms. The sensitivity and specificity of echo in identifying hemidiaphragms that needed plication were 100% and 81%, respectively. The positive predictive value and negative predictive value were 66% and 100%. Comparing reported diagnoses with blinded review, reviewers agreed with 97% diagnosed as normal, 81% of paralyzed, and 100% of paradoxical hemidiaphragms. Echocardiography was less accurate in discriminating between paralyzed and paradoxical diaphragm motion. Echocardiography was specific for paradoxical motion, since both patients identified by echocardiography were confirmed by fluoroscopy, but it was not sensitive. In nine patients, echo showed paralyzed motion that was identified by fluoroscopy as paradoxical.

CONCLUSIONS

This study supports the use of echocardiography in the assessment of diaphragm function. When the diaphragms are clearly visualized by echo, as they are in the majority of cases, the addition of an additional fluoroscopic study adds no clinical value. The differentiation between paralyzed and paradoxical motion is unreliable by both imaging modalities.