Diaphragmatic paralysis after cardiac surgery: how to look at it?

Ultrasonographic evaluation of diaphragm thickness and excursion in patients with cervical spinal cord injury

Objective: To evaluate the diaphragm thickness and excursion in patients with cervical spinal cord injury and reliability of diaphragmatic ultrasonography.Design: A Pilot Case-Control Study.Setting: China Rehabilitation Research Center (CRRC) /Beijing BO AI Hospital.Participants: Sixty participants with cervical spinal cord injury and sixty control participants were eligible for inclusion in this study.Interventions: Ultrasonographic evaluation of the diaphragm.Outcome Measures: All demographic data were evaluated. Diaphragm thickness, thickening ratio, and diaphragm excursions were assessed at the end of quiet tidal breathing and maximal inspiration. The reliability of inter- and intra-ultrasonography operators were evaluated.Results: Diaphragm thickness was significantly higher in patients with cervical spinal cord injury than the control group (P < 0.001). Diaphragmatic excursion of the right hemidiaphragm was significantly greater in patients with cervical spinal cord injury than the control group (P < 0.001) at the end of quiet tidal breathing. No difference was found in diaphragmatic excursion between two groups (P = 0.32) at the end of maximal inspiration. No significant difference was shown between two groups in thickening ratio. Intraclass correlation coefficients of inter-and intra-ultrasonography operators for the thickness and excursions of the diaphragm were greater than 0.93.Conclusion: Compared with the control group the diaphragm in patients with cervical spinal cord injury is hypertrophied and the diaphragm excursion is greater. Ultrasound is a highly reliable tool for the evaluation of diaphragm thickness and excursion in patients with cervical spinal cord injury.Trial Registration: This trail was registered in Chinese Clinical Trial Registry (NO. ChiCTR-ROC-17010973).

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.

Sensitivity and specificity of diagnostic ultrasound in the diagnosis of phrenic neuropathy

OBJECTIVES

To determine the sensitivity and specificity of B-mode ultrasound in the diagnosis of neuromuscular diaphragmatic dysfunction, including phrenic neuropathy.

METHODS

A prospective study of patients with dyspnea referred to the EMG laboratory over a 2-year time frame for evaluation of neuromuscular respiratory failure who were recruited consecutively and examined with ultrasound for possible diaphragm dysfunction. Sonographic outcome measures were absolute thickness of the diaphragm and degree of increased thickness with maximal inspiration. The comparison standard for diagnosis of diaphragm dysfunction was the final clinical diagnosis of clinicians blinded to the diaphragm ultrasound results, but taking into account other diagnostic workup, including chest radiographs, fluoroscopy, phrenic nerve conduction studies, diaphragm EMG, and/or pulmonary function tests.

RESULTS

Of 82 patients recruited over a 2-year period, 66 were enrolled in the study. Sixteen patients were excluded because of inconclusive or insufficient reference testing. One hemidiaphragm could not be adequately visualized; therefore, hemidiaphragm assessment was conducted in a total of 131 hemidiaphragms in 66 patients. Of the 82 abnormal hemidiaphragms, 76 had abnormal sonographic findings (atrophy or decreased contractility). Of the 49 normal hemidiaphragms, none had a false-positive ultrasound. Diaphragmatic ultrasound was 93% sensitive and 100% specific for the diagnosis of neuromuscular diaphragmatic dysfunction.

CONCLUSION

B-mode ultrasound imaging of the diaphragm is a highly sensitive and specific tool for diagnosis of neuromuscular diaphragm dysfunction.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that diaphragmatic ultrasound performed by well-trained individuals accurately identifies patients with neuromuscular diaphragmatic respiratory failure (sensitivity 93%; specificity 100%).

Neuromuscular ultrasound for evaluation of the diaphragm

Neuromuscular clinicians are often asked to evaluate the diaphragm for diagnostic and prognostic purposes. Traditionally, this evaluation is accomplished through history, physical exam, fluoroscopic sniff test, nerve conduction studies, and electromyography (EMG). Nerve conduction studies and EMG in this setting are challenging, uncomfortable, and can cause serious complications, such as pneumothorax. Neuromuscular ultrasound has emerged as a non-invasive technique that can be used in the structural and functional assessment of the diaphragm. In this study we review different techniques for assessing the diaphragm using neuromuscular ultrasound and the application of these techniques to enhance diagnosis and prognosis by neuromuscular clinicians.

Hemidiaphragmatic paralysis in preterm neonates: a rare complication of peripherally inserted central catheter extravasation

Unilateral diaphragmatic paralysis was diagnosed in 2 preterm neonates born at 29 and 25 weeks of gestation, respectively. In both instances, the pathophysiology was phrenic nerve injury after extravasation of parenteral nutrition fluid. Misplacement and infection were predisposing factors. Diaphragmatic movement analysis by time-motion-mode ultrasonography was helpful in achieving a diagnosis. The first neonate required a diaphragmatic placation, whereas the other infant was managed nonoperatively. These cases confirm a rare etiology of diaphragmatic paralysis and possible spontaneous recovery. In neonates with very low birth weight, general anesthesia and thoracic surgery may be associated with a high morbidity, suggesting that nonoperative medical treatment, when possible, is preferable if the neonate does not require supplemental oxygen.