Diaphragm and Lung Transplantation.

Mutual interactions between the diaphragm and lung transplantation (LTx) are known to exist. Before LTx, many factors can exert notable impact on the diaphragmatic function, such as the underlying respiratory disease, the comorbidities, and the chronic treatments of the patient. In the post-LTx setting, even the surgical procedure itself can cause a stressful trauma to the diaphragm, potentially leading to morphological and functional alterations. Conversely, the diaphragm can significantly influence various aspects of the LTx process, ranging from graft-to-chest cavity size matching to the long-term postoperative respiratory performance of the recipient. Despite this, there are still no standard criteria for evaluating, defining, and managing diaphragmatic dysfunction in the context of LTx to date. This deficiency hampers the accurate assessment of those factors which affect the diaphragm and its reciprocal influence on LTx outcomes. The objective of this narrative review is to delve into the complex role the diaphragm plays in the different stages of LTx and into the modifications of this muscle following surgery.

The efficacy of ultrasound-guided upper thoracic erector spinae plane block for postoperative analgesia in proximal shoulder surgery and its effect on phrenic nerve function: A prospective exploratory study.

Background and Aims: The upper thoracic (T2) erector spinae plane block (UT-ESPB) has been proposed as an alternative to interscalene brachial plexus block for postoperative analgesia in shoulder surgery. The current study was conducted to evaluate the same. Material and Methods: Patients scheduled for shoulder surgery under general anesthesia (GA) received ultrasound-guided UT-ESPB. The outcomes measured were diaphragmatic movements, block characteristics, and quality of recovery at 24 h. Results: A total of 43 patients were recruited. The incidence of phrenic nerve palsy was 0%. The sensory level achieved by the maximum number of patients at the end of 30 min was C7-T5 level, and none had a motor block. Forty-two percent of patients did not require rescue analgesia till 24 h postoperative. In the rest of the patients, the mean (SD) duration of analgesia was 724.2 ± 486.80 min, and the mean postoperative requirement of fentanyl was 98.80 ± 47.02 µg. The median pain score (NRS) during rest and movement is 2 to 3 and 3 to 4, respectively. The median quality of recovery score at the end of 24 h after the block was 14 (15-14). Conclusion: The upper thoracic ESPB resulted in a sensory loss from C7-T5 dermatomes without any weakness of the diaphragm and upper limb. However, the block was moderately effective in terms of the total duration of analgesia, postoperative pain scores, analgesic requirement, and quality of recovery in patients undergoing proximal shoulder surgeries under GA. Further studies are required to establish its role due to its poor correlation with sensory spread.

A randomized controlled trial of the size-adjustable cryoballoon vs conventional cryoballoon for paroxysmal atrial fibrillation: The CONTRAST-CRYO II trial rationale and design.

Background: Pulmonary vein isolation (PVI) with cryoballoon technology is a well-established therapy for treatment of atrial fibrillation (AF). Recently, a size-adjustable cryoballoon (POLARxTM FIT) that enables delivery in a standard 28-mm or an expanded 31-mm size was introduced. Objective: The purpose of this study was to perform a randomized clinical trial to evaluate the safety and efficacy of this novel cryoballoon compared to the conventional cryoballoon. Methods: The CONTRAST-CRYO II trial is a multicenter, prospective, open-label, randomized controlled trial in which 214 patients with paroxysmal AF will be randomized 1:1 to cryoballoon ablation with either a conventional cryoballoon (Arctic Front AdvanceTM Pro) or a size-adjustable cryoballoon (POLARx FIT). The study was approved by the Institutional Review Boards at all investigational sites and has been registered in the UMIN Clinical Trials Registry (UMIN000052500). Results: The primary endpoint of this study will be the incidence of phrenic nerve injury. Secondary endpoints include procedural success, chronic success through 12 months, procedure-related adverse events, biophysiological parameters during applications for each pulmonary vein (PV), total procedural and fluoroscopy times, level of PVI and isolation area, and probability of non-PV foci initiating AF. Conclusion: The CONTRAST-CRYO II trial is a multicenter, prospective, randomized controlled trial designed to assess the safety and efficacy of the POLARx FIT vs the Arctic Front Advance Pro. The findings from this trial will provide additional utility data on the efficacy of the size-adjustable cryoballoon for isolating PVs in patients with paroxysmal AF.

A Case of Hospitalization After Pre-operative Interscalene Nerve Block in an Ambulatory Surgery Center.

Interscalene nerve block (ISB) is an effective and low-risk local anesthetic (LA) procedure that is commonly employed for shoulder surgery. While phrenic nerve involvement occurs to some degree in every ISB procedure, the incidence of hypoxemia and other clinical signs of diaphragmatic disruption is much lower. This is a case of a 36-year-old female with no underlying respiratory disease who developed hypoxemia requiring a night of observation following an ISB for a rotator cuff repair procedure in an ambulatory surgical center. Her hypoxemia was easily treated with supplemental oxygen and she made a full recovery by the next day. The use of ultrasound guidance, reduced LA volume, less potent medication, sterile fluid for optimal visualization, and extrafascial administration should be considered for all patients receiving an ISB to prevent respiratory complications.

Functional Outcome following Phrenic Nerve Transfer in Brachial Plexus Injury.

Background: Brachial plexus injuries are debilitating injuries resulting in paralyzed shoulder to global paralysis of the upper extremity. Treatment strategies have evolved over the years with nerve transfer forming the mainstay of surgical management. Phrenic nerve provides certain advantages as donor over other options but has been less preferred due to fear of pulmonary complications. In this study, we assess the functional outcomes of phrenic nerve transfer in brachial plexus injuries. Materials and Methods: A retrospective study was performed on 18 patients operated between 2012 and 2017. The mean duration of injury to surgery was 4.56 months and mean follow-up was for 3.66 years. Phrenic nerve was used as donor to neurotize either biceps and brachialis branch of musculocutaneous nerve or suprascapular nerve. Assessment was done through Waikakul score for elbow flexion and Medical Research Council grading for shoulder abduction. Respiratory function assessment was done through questionnaire. Results: Twelve (80%) patients recovered grade 3 and above elbow flexion with 6 patients having a positive endurance test according to Waikakul and a "very good" result. In phrenic to suprascapular transfer group (3 patients), all patients had more than grade 3 recovery of shoulder abduction. No patient complained of respiratory problems. Conclusion: Phrenic nerve can be used as a reliable donor with suitable patient selection with good results in regaining muscle power without any anticipated effects on respiratory function.

Fluoroscopic sniff test as a diagnostic tool for phrenic nerve injury in patients with traumatic brachial plexus injury.

OBJECTIVE: Traumatic brachial plexus injury (BPI) is a high-morbidity condition with an escalating incidence. One of the treatment options is neurotization using the ipsilateral phrenic nerve. Therefore, diagnosis of nerve dysfunction is a crucial step in preoperative planning. This study aimed to assess the accuracy and reliability of the fluoroscopic sniff test for preoperative diagnosis of phrenic nerve injury in patients with traumatic BPI. METHODS: The study was conducted from June 2019 to August 2023 at a tertiary care hospital. A preoperative fluoroscopic sniff test was performed. During brachial plexus surgery, direct phrenic nerve stimulation was conducted as a gold standard of phrenic nerve function. Two nonoperating orthopedic surgeons interpreted the accuracy and reliability of the test. RESULTS: Seventy-four patients with traumatic BPI (66 males and 8 females) with a median age of 26 years were enrolled. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the fluoroscopic sniff test were 90.9% (95% CI 75.7%-98.1%), 100% (95% CI 91.4%-100%), 100% (95% CI 88.4%-100%), 93.2% (95% CI 82.3%-97.6%), and 95.9% (95% CI 88.6%-99.2%), respectively. Interobserver reliability showed excellent agreement (κ = 1, p < 0.001). CONCLUSIONS: The fluoroscopic sniff test was proven to be an accurate, reliable, and simple tool to evaluate phrenic nerve function in patients with traumatic BPI. Preoperative testing should be performed to reduce operative time to identify the phrenic nerve as a donor for nerve transfer surgery in cases in which no function is detected from the fluoroscopic sniff test.

Effects of a novel osteopathic visceral technique for the pancreas on pain and range of motion in a patient with neck pain: Case report.

INTRODUCTION: Neck pain is a leading cause of disability worldwide. Visceral referred pain is a common form of disease-induced pain, with visceral nociception being referred to somatic tissues. OBJECTIVE: The aim of this case report was to evaluate the immediate and long term effects of a novel osteopathic visceral technique (OVT) on pain and cervical range of motion (CROM) in a patient with nonspecific neck pain (NS-NP). METHOD: A case of a 47-year-old female suffering with NS-NP for four months. The patient had sought physiotherapy treatment several times, and occasionally used anti-inflammatory medication to relieve symptoms. The patient presented muscle cervical tenderness and hyperalgesia over the spinous processes of C3-C4 spinal segments with limited CROM. A novel osteopathic visceral manipulation (OVM) technique was applied in the epigastric region targeting the pancreas. Immediately after the treatment, the patient reported reduction in pain evaluated with the numerical evaluation scale (NRS), and a clinically significant increase in pressure pain threshold (PPT) in C3 spinous process. Improvement in CROM was also observed. The post-treatment improvements have been maintained at 1-month of follow-up assessment. CONCLUSION: A single OVT was effective in reducing cervical pain and increasing CROM in a patient with NS-NP caused by a viscerosomatic reflex. The results of this case study provides preliminary evidence that OVM can produce hypoalgesia in somatic tissues with segmentally related innervation. This finding encourages future research to gain a better understanding of the mechanisms of regional inhibitory interdependence involving the viscerosomatic reflexes of OVM.

Effects of COVID-19 Pandemic in Patients with a Previous Phrenic Nerve Transfer for a Traumatic Brachial Plexus Palsy.

Background With the advent of the coronavirus disease 2019 (COVID-19) pandemic, some doubts have been raised regarding the potential respiratory problems that patients who previously underwent a phrenic nerve transfer could have. Objectives To analyze the effects of the coronavirus infection on two populations, one from Argentina and another from Taiwan. Specific objectives were: (1) to identify the rate of COVID in patients with a history of phrenic nerve transfer for treatment of palsy; (2) to identify the overall symptom profile; (3) to compare Argentinian versus Taiwanese populations; and (4) to determine if any phrenic nerve transfer patients are at particular risk of more severe COVID. Methods A telephonic survey that included data regarding the number of episodes of acute COVID-19 infection, the symptoms it caused, the presence or absence of potential or life-threatening complications, and the status of COVID-19 vaccination were studied. Intergroup comparisons were conducted using the nonparametric Mann-Whitney U test, with categorical variables conducted using either the Pearson χ2 analysis or the Fisher's exact test, as appropriate. Results A total of 77 patients completed the survey, 40 from Taiwan and 37 from Argentina. Fifty-five (71.4%) developed a diagnosis of COVID. However, among these, only four had any level of dyspnea reported (4/55 = 7.3%), all mild. There were also no admissions to hospital or an intensive care unit, no intubations, and no deaths. All 55 patients isolated themselves at home. Conclusions It can be concluded that an acute COVID-19 infection was very well tolerated in our patients. (Level of evidence 3b, case reports).

Bilateral Phrenic Nerve Palsy Associated With Neuralgic Amyotrophy.

Neuralgic amyotrophy (NA) is a multifocal inflammatory neuropathy accompanied by acute pain and muscle atrophy. NA commonly affects the upper extremities, but rarely affects the phrenic nerve. Here, we report a male with neck pain, orthopnea, difficulty sleeping in the supine position, and inability to slurp. His saturated oxygen level decreased from 97% to 86% in the supine position. His right shoulder showed muscle atrophy. Chest X-ray examination in the supine position and a nerve conduction study showed phrenic palsy. We diagnosed it as bilateral phrenic nerve palsy associated with NA. NA sometimes causes phrenic nerve palsy and may cause slurping difficulty.

Management of Diaphragm Paralysis and Eventration.

An elevated diaphragm may be due to eventration or paralysis. Diaphragm elevation is often asymptomatic and found incidentally on imaging. Fluoroscopic testing can be used to differentiate eventration (no paradoxic motion) from paralysis (paradoxic motion). Regardless of etiology, a diaphragm plication is indicated in all symptomatic patients with an elevated diaphragm. Plication can be approached either from a thoracic or abdominal approach, though most thoracic surgeons perform minimally invasive thoracoscopic plication. The goal of plication is to improve lung volumes and decrease paradoxic elevation of the hemidiaphragm. Diaphragm plication is safe, has excellent outcomes, and is associated with symptom improvement.

Effects of exercise and doxorubicin on acute diaphragm neuromuscular transmission failure.

Doxorubicin (DOX) is a highly effective anthracycline antibiotic used to treat a wide variety of cancers including breast cancer, leukemia and lymphoma. Unfortunately, clinical use of DOX is limited due to adverse off-target effects resulting in fatigue, respiratory muscle weakness and dyspnea. The diaphragm is the primary muscle of inspiration and respiratory insufficiency is likely the result of both muscle weakness and neural impairment. However, the contribution of neuropathology to DOX-induced respiratory muscle dysfunction is unclear. We hypothesized that diaphragm weakness following acute DOX exposure is associated with neurotoxicity and that exercise preconditioning is sufficient to improve diaphragm muscle contractility by maintaining neuromuscular integrity. Adult female Sprague-Dawley rats were randomized into four experimental groups: 1) sedentary-saline, 2) sedentary-DOX, 3) exercise-saline or 4) exercise-DOX. Endurance exercise preconditioning consisted of treadmill running for 1 h/day at 30 m/min for 10 days. Twenty-four hours after the last bout of exercise, animals were treated with DOX (20 mg/kg, I.P.) or saline (equal volume). Our results demonstrate that 48-h following DOX administration diaphragm muscle specific force is reduced in sedentary-DOX rats in response to both phrenic nerve and direct diaphragm stimulation. Importantly, endurance exercise preconditioning in DOX-treated rats attenuated the decrease in diaphragm contractile function, reduced neuromuscular transmission failure and altered phrenic nerve morphology. These changes were associated with an exercise-induced reduction in circulating biomarkers of inflammation, nerve injury and reformation. Therefore, the results are consistent with exercise preconditioning as an effective way of reducing respiratory impairment via preservation of phrenic-diaphragm neuromuscular conduction.

Subdiaphragmatic phrenic nerve supply: A systematic review.

OBJECTIVE: The aim of this systematic review is to study the subdiaphragmatic anatomy of the phrenic nerve. MATERIALS AND METHODS: A computerised systematic search of the Web of Science database was conducted. The key terms used were phrenic nerve, subdiaphragmat*, esophag*, liver, stomach, pancre*, duoden*, intestin*, bowel, gangli*, biliar*, Oddi, gallbladder, peritone*, spleen, splenic, hepat*, Glisson, falciform, coronary ligament, kidney, suprarenal, and adrenal. The 'cited-by' articles were also reviewed to ensure that all appropriate studies were included. RESULTS: A total of one thousand three hundred and thirty articles were found, of which eighteen met the inclusion and exclusion criteria. The Quality Appraisal for Cadaveric Studies scale revealed substantial to excellent methodological quality of human studies, while a modified version of the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias Tool denoted poor methodological quality of animal studies. According to human studies, phrenic supply has been demonstrated for the gastro-esophageal junction, stomach, celiac ganglia, liver and its coronary ligament, inferior vena cava, gallbladder and adrenal glands, with half of the human samples studied presenting phrenic nerve connections with any subdiaphragmatic structure. CONCLUSIONS: This review provides the first systematic evidence of subdiaphragmatic phrenic nerve supply and connections. This is of interest to professionals who care for people suffering from neck and shoulder pain, as well as patients with peridiaphragmatic disorders or hiccups. However, there are controversies about the autonomic or sensory nature of this supply.

Incidence of phrenic nerve injury during pulmonary vein isolation using different cryoballoons: data from a large prospective ablation registry.

AIMS: Phrenic nerve injury (PNI) is the most common complication during cryoballoon ablation. Currently, two cryoballoon systems are available, yet the difference is unclear. We sought to compare the acute procedural efficacy and safety of the two cryoballoons. METHODS: This prospective observational study consisted of 2,555 consecutive atrial fibrillation (AF) patients undergoing pulmonary vein isolation (PVI) using either conventional (Arctic Front Advance) (AFA-CB) or novel cryoballoons (POLARx) (POLARx-CB) at 19 centers between January 2022 and October 2023. RESULTS: Among 2,555 patients (68.8 ± 10.9 years, 1,740 men, paroxysmal AF[PAF] 1,670 patients), PVIs were performed by the AFA-CB and POLARx-CB in 1,358 and 1,197 patients, respectively. Touch-up ablation was required in 299(11.7%) patients. The touch-up rate was significantly lower for POLARx-CB than AFA-CB (9.5% vs. 13.6%, p = 0.002), especially for right inferior PVs (RIPVs). The touch-up rate was significantly lower for PAF than non-PAF (8.8% vs. 17.2%, P < 0.001) and was similar between the two cryoballoons in non-PAF patients. Right PNI occurred in 64(2.5%) patients and 22(0.9%) were symptomatic. It occurred during the right superior PV (RSPV) ablation in 39(1.5%) patients. The incidence was significantly higher for POLARx-CB than AFA-CB (3.8% vs. 1.3%, P < 0.001) as was the incidence of symptomatic PNI (1.7% vs. 0.1%, P < 0.001). The difference was significant during RSPV (2.5% vs. 0.7%, P < 0.001) but not RIPV ablation. The PNI recovered more quickly for the AFA-CB than POLARx-CB. CONCLUSIONS: Our study demonstrated a significantly higher incidence of right PNI and lower touch-up rate for the POLARx-CB than AFA-CB in the real-world clinical practice.

Interest of thoracic ultrasound after cardiac surgery or interventional cardiology.

Thoracic ultrasound has attracted much interest in detecting pleural effusion or pulmonary consolidation after cardiac surgery. In 2016, Trovato reported, in the World Journal of Cardiology, the interest of using, in addition to echocardiography, thoracic ultrasound. In this editorial, we highlight the value of assessing diaphragm function after cardiac surgery and interventional cardiology procedures. Various factors are able to impair diaphragm function after such interventions. Diaphragm motion may be decreased by chest pain secondary to sternotomy, pleural effusion or impaired muscle function. Hemidiaphragmatic paralysis may be secondary to phrenic nerve damage complicating cardiac surgery or atrial fibrillation ablation. Diagnosis may be delayed. Indeed, respiratory troubles induced by diaphragm dysfunction are frequently attributed to pre-existing heart disease or pulmonary complications secondary to surgery. In addition, elevated hemidiaphragm secondary to diaphragm dysfunction is sometimes not observed on chest X-ray performed in supine position in the intensive care unit. Analysis of diaphragm function by ultrasound during the recovery period appears essential. Both hemidiaphragms can be studied by two complementary ultrasound methods. The mobility of each hemidiaphragms is measured by M-mode ultrasonography. In addition, recording the percentage of inspiratory thickening provides important information about the quality of muscle function. These two approaches make it possible to detect hemidiaphragm paralysis or dysfunction. Such a diagnosis is important because persistent diaphragm dysfunction after cardiac surgery has been shown to be associated with adverse respiratory outcome. Early respiratory physiotherapy is able to improve respiratory function through strengthening of the inspiratory muscles i.e. diaphragm and accessory inspiratory muscles.

Diaphragm movement sensor for phrenic nerve monitoring during cryoballoon procedures: the first clinical evaluation.

Background and aims: Right phrenic nerve palsy is the most frequent complication of cryoballoon procedures. The SMARTFREEZE™ console (Boston Scientific, St. Paul, MN, USA) has integrated a new tool for diaphragm monitoring-the Diaphragm Movement Sensor; however, it has not been evaluated in clinical practice. We aimed to assess the diagnostic performance of the Diaphragm Movement Sensor based on compound motor action potential data recorded simultaneously. Methods: Thirty consecutive patients (mean age 63.2 ± 10.2 years) were included. We simultaneously recorded the compound motor action potential and the Diaphragm Movement Sensor during cryoapplications in the right pulmonary veins. The right phrenic nerve was paced at 60 per minute, 12 V and 2.9 ms. Compound motor action potential monitoring with a 30% decrease cutoff for the diagnosis of phrenic nerve threatening was considered the gold standard. The Diaphragm Movement Sensor decrease threshold was also set at 30%. Results: Considering compound motor action potential monitoring, phrenic nerve threatening occurred 11 times (in seven patients) among 84 cryoapplications (13.1%) at the right pulmonary veins. The sensitivity and specificity of the Diaphragm Movement Sensor were, respectively, 33% (95% CI: 7%-70%) and 49% (95% CI: 38%-61%; P < 0.001). The predictive positive and negative values for the Diaphragm Movement Sensor were, respectively, 7% (95% CI: 2%-20%) and 86% (95% CI: 72%-95%). The Diaphragm Movement Sensor gave an erroneous diagnosis in 44/84 cryoapplications (52.4%). Conclusions: The diagnostic performance of the Diaphragm Movement Sensor is low, and the relevance of its use in clinical practice may be debated.

The Effects of Volatile Anesthetics on Renal Sympathetic and Phrenic Nerve Activity during Acute Intermittent Hypoxia in Rats.

Coordinated activation of sympathetic and respiratory nervous systems is crucial in responses to noxious stimuli such as intermittent hypoxia. Acute intermittent hypoxia (AIH) is a valuable model for studying obstructive sleep apnea (OSA) pathophysiology, and stimulation of breathing during AIH is known to elicit long-term changes in respiratory and sympathetic functions. The aim of this study was to record the renal sympathetic nerve activity (RSNA) and phrenic nerve activity (PNA) during the AIH protocol in rats exposed to monoanesthesia with sevoflurane or isoflurane. Adult male Sprague-Dawley rats (n = 24; weight: 280-360 g) were selected and randomly divided into three groups: two experimental groups (sevoflurane group, n = 6; isoflurane group, n = 6) and a control group (urethane group, n = 12). The AIH protocol was identical in all studied groups and consisted in delivering five 3 min-long hypoxic episodes (fraction of inspired oxygen, FiO2 = 0.09), separated by 3 min recovery intervals at FiO2 = 0.5. Volatile anesthetics, isoflurane and sevoflurane, blunted the RSNA response to AIH in comparison to urethane anesthesia. Additionally, the PNA response to acute intermittent hypoxia was preserved, indicating that the respiratory system might be more robust than the sympathetic system response during exposure to acute intermittent hypoxia.

Rare case of divided phrenic nerve variation: a cadaveric case report.

The phrenic nerve innervates the respiratory diaphragm, the primary muscle active during ventilation. The canonical path of the phrenic nerve originates from the cervical spine at C3-C5 spinal nerves and travels inferiorly through the neck and thoracic cavity to reach the diaphragm. During a cadaver dissection, a variation of the phrenic nerve was discovered in a 93-year-old male specimen. A traditional origin of the phrenic nerve was noted; however, the nerve branched into medial and lateral components at the level of the superior trunk of the brachial plexus. The branches reconnected at the apex of the aortic arch and continued inferiorly to innervate the ipsilateral diaphragm. This case study describes a rare type of branching of the phrenic nerve and explores its potential impact on clinical procedures.

Proposal for Manual Osteopathic Treatment of the Phrenic Nerve.

The article reviews the anatomical path of the phrenic nerve and its anastomoses, with the most up-to-date knowledge reported in the literature. We have briefly reviewed the possible phrenic dysfunctions, with the final aim of presenting an osteopathic manual approach for the treatment of the most superficial portion of the nerve, using a gentle technique. The approach we propose is, therefore, a theory based on clinical experience and the rationale that we can extrapolate from the literature. We hope that the article will be a stimulus for further experimental investigations using the technique illustrated in the article. To the authors' knowledge, this is the first article that takes into consideration the hypothesis of an osteopathic treatment with gentle techniques for the phrenic nerve.