Diaphragmatic paralysis following cervical chiropractic manipulation: case report and review

This case report documents an uncommon cause of bilateral diaphragmatic paralysis resulting from phrenic nerve injury during cervical chiropractic manipulation. Several months after the initial injury, our patient remains short of breath and has difficulty breathing in the supine position. Other causes of diaphragmatic paralysis and phrenic nerve injury are reviewed.     

Insidious phrenic nerve involvement in postpolio syndrome

A 49-year-old woman with amyotrophic sequelae of poliomyelitis experienced progressive left upper limb weakness and breathing discomfort while walking that had developed over one year prior to presentation. She had flaccid quadriplegia which was more marked in the left upper limb, with the C4- and C5-innervated muscles being most severely affected. Chest radiographs double exposed at maximal inspiration and expiration revealed poor respiratory movements in the left hemidiaphragm. Phrenic nerve conduction study demonstrated conspicuous diaphragmatic paralysis on the left side. The electrophysiological study supports radiological findings and provides useful evidence for insidious phrenic nerve involvement in postpolio syndrome.     

Partial unilateral phrenic nerve paralysis caused by a large intrathoracic goitre

Intrathoracic goitres may cause a variety of symptoms caused by compression of the trachea, neural structures, blood vessels and the oesophagus. A case history is presented of a patient with a recurrent goitre after subtotal thyroidectomy who displayed partial unilateral phrenic paralysis, which subsided after a second subtotal thyroidectomy. Compression of the phrenic nerve appears to be a very rare manifestation of an intrathoracic goitre and thus far has never been reported.     

Electrophysiologic evaluation of phrenic nerves in severe respiratory insufficiency requiring mechanical ventilation

Diaphragmatic paralysis in patients with respiratory insufficiency compounds the problems in the management. In the presence of lower lobe atelectasis, pleural effusion, or a patient's poor respiratory effort, fluoroscopic examination is often not a reliable way to diagnose diaphragmatic paralysis. We observed that transcutaneous phrenic nerve stimulation in the neck and recording the diaphragmatic potentials from electrodes placed on the lower part of the chest is a simple, reliable, and noninvasive technique to diagnose diaphragmatic dysfunction at the bedside in critically ill patients. In 14 postoperative patients and one with cervical spinal cord injury with respiratory failure, we found ten patients who showed phrenic nerve dysfunction. Besides diagnostic utility, the electrophysiologic evaluation of phrenic-diaphragmatic function provides critical information needed for therapy.     

Inhibitory and excitatory effects on respiration by phrenic nerve afferent stimulation in cats

Respiratory effects of electrical stimulation of phrenic nerve afferents were studied in anesthetized cats, either spontaneously breathing or paralyzed and ventilated. The type of phrenic afferent fibers activated was controlled by recording the evoked action potentials from dorsal root fibers. In both preparations, stimulation at a strength sufficient to activate small diameter myelinated phrenic nerve afferents induced a biphasic response. The first phase lasted a few respiratory cycles and was inhibitory and consisted of a decrease in tidal volume (VT) or phrenic activity (NA), inspiratory time (TI), respiratory duty cycle (TI/Ttot) and instantaneous ventilation (VE) or minute phrenic activity (NMA). Expiratory time (TE) increased and breathing frequency (f) and mean inspiratory flow (VT/TI) or mean inspiratory neural activity (NA/TI) did not change. This short-term response was suppressed in animals pretreated with bicuculline. The second phase was a long-term excitation in which VT or NA, f, VE or NMA and VT/TI increased whereas both TI and TI/Ttot decreased and TE did not change. Unlike published data, our results suggest that small-diameter myelinated phrenic nerve afferents are involved in these responses. These phrenic fibers, like afferents from other muscles, affect respiratory output and may play a role in the control of breathing.     

Diaphragmatic paralysis caused by malposition of chest tube placement after pediatric cardiac surgery

Diaphragmatic paralysis is a recognized complication after pediatric cardiac surgery. It is universally acknowledged that direct phrenic nerve injury during surgery is the etiology. However, we experienced two unusual cases of diaphragmatic paralysis following malposition of chest tube placement after pediatric cardiac surgery. The malposition of too deeply placed chest tube with resultant phrenic nerve injury was presumably the underlying cause. One patient underwent successful diaphragmatic plication due to intractable respiratory distress. The other was asymptomatic. Our report highlights the previously unreported complication of chest tube-induced phrenic nerve injury following its malposition after pediatric cardiac surgery. Prompt recognition and correction of tube malposition or selection of a softer chest tube probably can ameliorate the problem.     

Influence of lung volume on respiratory responses to spontaneous bladder contractions

Spontaneous bladder contractions (SBCs) in decerebrate, vagotomized, paralyzed, ventilated cats have been shown to decrease phrenic and hypoglossal inspiratory nerve activities, as well as the activities of other respiratory motor nerves. To determine whether vagal afferents from the lung influence the respiratory inhibition associated with SBCs, we recorded phrenic and hypoglossal nerve activities in decerebrate, paralyzed, vagally intact cats. The animals were ventilated by a servo-respirator, which inflated the lungs in accordance with integrated phrenic nerve activity. Maintained increases in end-expiratory lung volume were produced by the application of 2–10 cm H₂O positive end-expiratory pressure (PEEP). SBCs were accompanied by decreases in both phrenic and hypoglossal peak integrated nerve activities, as well as by marked decreases in respiratory frequency. The reduction of respiratory frequency was greater with higher levels of PEEP, a few animals becoming apneic during SBCs. After bilateral vagotomy, SBCs continued to decrease phrenic and hypoglossal peak integrated nerve activities as previously reported, but the reduction of respiratory frequency was much less striking than when the vagi were intact. These results indicate that activity of vagal afferents from the lung augments the respiratory influence of SBCs. Furthermore, SBCs in vagally intact animals can induce periodic breathing.     

Phrenic afferent input to the lateral medullary reticular formation of the cat

The afferent inputs from phrenic nerve stimulation to the lateral reticular formation of the lower brain stem were studied in anesthetized spontaneously breathing cats. The activity of reticular neurons was recorded by means of extracellular tungsten microelectrodes. Electrical stimulation of the central end of the right phrenic nerve evoked excitatory or inhibitory responses in the lateral reticular nucleus (LRN), in the nucleus ambiguus (AMB) and in a region dorsal to the AMB of ipsi- and contralateral sides. Phrenic afferents belonging to the flexor reflex afferent group were involved in these responses. The discharge pattern of the respiratory related units (RRU) of the AMB were exceptionally affected by phrenic nerve stimulations. It is concluded that high threshold phrenic afferents relay in the LRN before projecting to the cerebellar cortex. The overlapping of respiratory and non-respiratory afferents in the reticular formation may participate to the adaptations of respiratory and somatomotor functions during specific behaviors.     

Recovery after unilateral phrenic injury associated with coronary artery revascularization

Hemidiaphragmatic paralysis occurs in some patients following CAB surgery, possibly related to an intraoperative stretch or cold-induced phrenic injury. To determine the time and extent of recovery of phrenic nerve function, we studied five patients with left phrenic paresis or paralysis after CAB. The FVC, FEV1, Pmax and PEmax pressures, latency of conduction and amplitude of CDAP with phrenic nerve stimulation, and diaphragmatic excursion during fluoroscopy were measured for 12 months after CAB. Left phrenic paralysis was substantiated in four of five patients, and paresis was present in the other patient. Recovery of the left phrenic nerve occurred in all patients, complete in one and partial in four, but was delayed and continued for up to 12 months. We conclude that phrenic nerve recovery is delayed after CAB-associated injury and may be incomplete up to 14 months later, in keeping with rates of regeneration of other peripheral nerves.     

Dyspnea induced by hemidiaphragmatic paralysis after ultrasound-guided supraclavicular brachial plexus block in a morbidly obese patient

Rationale:Hemidiaphragmatic paralysis (HDP) is a frequent complication of the brachial plexus block, caused by unintentional blockade of ipsilateral phrenic nerve. HDP did not rise enough alarm and attention to most anesthesiologists, because most patients with no coexisting comorbid diseases are asymptomatic and able to tolerate it. However, it may cause severe respiratory complication for patients with preexisting compromised cardiorespiratory function.Patient concerns:A 67-year-old woman with morbidly obesity was planned to receive opening reduction and internal fixation of right humeral shaft fracture under regional anesthesia considering less respiratory and cardiovascular system interference compared with general anesthesia.Diagnoses:After ultrasound guided supraclavicular brachial plexus block, the patient developed severe hypoxia and hypercapnia.Unintentional block of phrenic nerve and diaphragm paralysis was diagnosed by diaphragm ultrasound, which was considered as the main reason of severe hypoxia.Interventions:It led to a conversion from regional anesthesia to general anesthesia with endotracheal intubation for patient''s safety and smooth operation.Outcomes:The unintentional phrenic nerve block leads to a prolonged ventilation time, length of stay in intensive care unit and length of stay in hospital.Lessons:This case report highlights the risk of diaphragm paralysis in morbidly obese patients. Though new diaphragm sparing brachial plexus block (BPB) methods were developed intended to reduce the risk of HDP, no approaches could absolutely spare phrenic nerve involvement. Therefore, clinicians should always consider the risk of HDP associated with BPBs. For each individual, a detailed preoperative evaluation and sufficient preparation are paramount to avoid serious complications.     

Influence of extreme hypercapnia on respiratory motor nerve activity in cats

Sedative drugs have been found to depress the respiratory activity of upper airway muscles more than that of the diaphragm. To determine whether CO2 at narcotic levels has a similar action, we recorded phrenic and hypoglossal nerve activities in decerebrate, vagotomized, paralyzed cats. T5 or T6 external intercostal nerve activity was also recorded in some animals. End-tidal CO2 concentration was raised progressively to over 30% or until depression of nerve activity was apparent. Respiratory frequency was reduced by severe hypercapnia in most cats. Hypoglossal nerve activity was consistently decreased more than that of the phrenic nerve. In most cases intercostal nerve activity was also more susceptible than phrenic nerve activity to hypercapnic depression. The results indicate that CO2 at narcotic levels interferes both with the central pattern generator for breathing movements and with the expression of the pattern in specific motor nerves.     

Stimulus parameters for phrenic nerve pacing in infants and children

Phrenic nerve pacing has been used since 1966 to support breathing in quadriplegics and patients with central hypoventilation syndrome (CHS). Recently, using low-frequency, long-inspiratory-time (T_i) stimulation, phrenic nerve pacing has been used successfully to support breathing 24 hours per day in adults and older children. However, no similar experience exists for infants and young children. Therefore, in 27 studies in 14 infants and children we determined the effects of changing T_i and interpulse interval (the inverse of stimulus frequency) on ventilation. Diaphragmatic action potentials, airflow, tidal volume, P_ACO2 and Sa_O2 were measured during sleep. Phrenic nerve pacing proved useful in 13 of 14 patients to support breathing either during wakefulness (n = 7) or during sleep (n = 6). We found that adequate ventilation could be achieved at significantly longer interpulse intervals, 95 ± 25 (mean ± SD) ms, and shorter T_i, 580 ± 80 ms, than previously reported. At an average respiratory rate of 21 ± 8 breaths/min it was thus possible to maintain adequate ventilation despite a marked reduction in the number of phrenic nerve stimuli. Theoretically, these reductions in phrenic nerve stimulation should minimize the chance of pacing-induced diaphragmatic damage. These results suggest that 24 hour per day phrenic nerve pacing may be a realistic goal in selected infants and children.     

Influence of morphine on respiratory activities of phrenic and hypoglossal nerves in cats

Anesthetic and sedative drugs have been found to diminish the respiratory motor activity of the hypoglossal nerve more than that of the phrenic nerve. This differential depression of motor activity to the upper airway may contribute to the exacerbation of obstructive sleep apnea by sedative drugs. To determine whether morphine has a similar selective action, we recorded phrenic and hypoglossal nerve activities before and after morphine administration in decerebrate, vagotomized cats, paralyzed with gallamine. Morphine diminished the activities of both nerves in most animals, but the responses were highly variable, and no consistent pattern of differential depression was apparent. The variability of the results may reflect the complex nature of opiate actions on the control of breathing.     

Phrenic nerve injury due to thoracentesis for TPN effusion in a preterm newborn: consecutive two unusual complications

Central venous catheters ara commonly used in neonatal intensive care units as routes of parenteral nutrition. Pleural effusions caused by extravasation of parenteral alimentation fluid are a rare complication of central venous catheters in the newborn. Diaphragmatic paralysis due to phrenic nerve injury is a rare respiratory condition which may be life-threatening in infants.     

Respiratory response to baroreceptor stimulation and spontaneous contractions of the urinary bladder

Spontaneous contractions of the urinary bladder (SBCs) and experimental elevations of carotid sinus pressure (CSP) have been shown to result in respiratory inhibition with preferential reduction in hypoglossal (HG) nerve activity as compared with that of phrenic nerve discharge. We assessed the interaction between these respiratory inhibitory stimuli in decerebrate, vagotomized, paralyzed and artificially ventilated cats. We denervated the right carotid sinus and pressurized the isolated left carotid sinus region within the linear range of the baroreflex, while maintaining systemic arterial pressure at approximately 100 mmHg. We monitored the HG and phrenic nerve responses to SBCs, to elevations in CSP between SBCs, and to elevations in CSP during SBCs. Our results show that superimposing these stimuli results in respiratory inhibition, especially of HG activity, that exceeds that resultant from either stimulus alone. We speculate that the combined presence of SBCs and episodic hypertension may contribute to the development of periodic breathing or obstructive apnea, particularly during sleep.     

Orthopnea and tidal expiratory flow limitation in patients with euthyroid goiter

BACKGROUND: Nontoxic goiters can cause extrathoracic upper airway obstruction and, if large, may extend into the thorax, causing intrathoracic airway obstruction. Although patients with goiter often report orthopnea, there are few studies on postural changes in respiratory function in these subjects. PURPOSE: The aim of this study was to investigate the postural changes in respiratory function and the presence of flow limitation (FL) and orthopnea in patients with nontoxic goiter. METHODS: In 32 patients with nontoxic goiter, respiratory function was studied in seated and supine position. Expiratory FL was assessed with the negative expiratory pressure method. Goiter-trachea radiologic relationships were arbitrarily classified as follows: grade 1, no evidence of tracheal deviation; grade 2, tracheal deviation present in lateral and/or anteroposterior plane but with tracheal compression < 20%; and grade 3, tracheal deviation present with compression > 20%. Subgroups were considered according to this classification and occurrence of orthopnea and FL. RESULTS: In all three groups of patients, the average maximal expiratory flow at 50% of FVC/maximal inspiratory flow at 50% of FVC ratios were > 1.1, suggesting the presence of upper airway obstruction. Grade 3 patients had a significantly lower expiratory reserve volume and maximal expiratory flow at 25% of FVC and higher airway resistance and 3-point FL score than patients with grade 1 and grade 2. The prevalence of orthopnea was highest in patients with grade 3 (75%, as compared to 18% in the grade 1 group). In patients with orthopnea, the prevalence of intrathoracic goiter was also higher (78%, vs 21% in patients without orthopnea). CONCLUSION: There is a high prevalence of orthopnea in patients with goiter, especially when the location is intrathoracic and causes a reduction of end-expiratory lung volume and flow reserve in the tidal volume range, promoting FL especially in supine position. Obesity is a factor that increases the risk of orthopnea in patients with goiter.     

Diaphragmatic weakness and paralysis

Diaphragmatic weakness implies a decrease in the strength of the diaphragm. Diaphragmatic paralysis is an extreme form of diaphragmatic weakness. Diaphragmatic paralysis is an uncommon clinical problem while diaphragmatic weakness, although uncommon, is probably frequently unrecognized because appropriate tests to detect its presence are not performed. Weakness of the diaphragm can result from abnormalities at any site along its neuromuscular axis, although it most frequently arises from diseases in the phrenic nerves or from myopathies affecting the diaphragm itself. Presence of diaphragmatic weakness may be suspected from the complaint of dyspnea (particularly on exertion) or orthopnea; the presence of rapid, shallow breathing or, more importantly, paradoxical inward motion of the abdomen during inspiration on physical examination; a restrictive pattern on lung function testing; an elevated hemidiaphragm on chest radiograph; paradoxical upward movement of 1 hemidiaphragm during fluoroscopic imaging; or reductions in maximal static inspiratory pressure. The diagnosis of diaphragmatic weakness is confirmed, however, by a reduction in maximal static transdiaphragmatic pressure (Pdimax). The diagnosis of diaphragmatic paralysis is confirmed by the absence of a compound diaphragm action potential on phrenic nerve stimulation. There are many causes of diaphragmatic weakness and paralysis. In this review we outline an approach we have found useful in attempting to determine a specific cause. Most frequently the cause is either a phrenic neuropathy or diaphragmatic myopathy. Often the neuropathy or myopathy affects other nerves or muscles that can be more easily investigated to determine the specific pathologic basis, and, by association, it is presumed that the diaphragmatic weakness or paralysis is secondary to the same disease process.     

Unilateral diaphragmatic paralysis in a diabetic patient: a case of trepopnea

Dyspnea is a common presenting complaint. Trepopnea, an under-recognized form of dyspnea, is difficult breathing in only one lateral decubitus position. One cause of trepopnea is unilateral diaphragmatic paralysis, which in itself is an uncommon diagnosis. We report a unique case of a 55-year-old diabetic man who presented with trepopnea and was found to have unilateral diaphragmatic paralysis secondary to isolated diabetic phrenic neuropathy. This case highlights the importance of recognizing trepopnea as an early clinical symptom of diaphragmatic paralysis and discusses diabetic phrenic neuropathy which can occur in the absence of peripheral neuropathy.     

Mechanism of rib cage inspiratory muscle recruitment in diaphragmatic paralysis

Paralysis of the diaphragm promotes an increase in the activation of the rib cage inspiratory muscles, and previous studies have suggested that this compensation is primarily due to vagal mechanisms (6). To test this hypothesis, we have assessed the effect of diaphragmatic paralysis on the electrical response of 19 parasternal intercostal muscles in eight anesthetized, vagotomized, spontaneously breathing dogs in the supine posture. Complete diaphragmatic paralysis was induced by section of the C5, C6, and C7 phrenic nerve roots in the neck. With the animals breathing room air, diaphragmatic paralysis resulted in a mean 94% increase in the peak height of integrated parasternal activity (p less than 0.001) associated with a 14 mm Hg decrease in arterial PO2 (p less than 0.05) and an 8 mm Hg increase in arterial PCO2 (p less than 0.001). The augmented parasternal activity was unrelated to the duration of inspiration and persisted when the animals were given a hyperoxic gas mixture. Thus the rib cage inspiratory muscles still compensate for diaphragmatic paralysis in the absence of vagal signals and of hypoxemia. This compensation probably results from the considerably augmented CO2 load placed on the extradiaphragmatic muscles.     

Ventilatory effects of the interaction between phrenic and limb muscle afferents.

We studied the effects on ventilation and ventilatory muscle activation of stimulation of the central ends of the left phrenic and gastrocnemius nerves separately and concurrently in 10 spontaneously breathing, alpha-chloralose anaesthetized dogs. The nerves were stimulated for 1 min, at a frequency of 40 Hz and pulse duration of 1 ms. The phrenic nerve was stimulated at 20 and 40 times twitch threshold (TT). During these stimulation periods ventilation increased by 39% and 79% of control values, respectively. The gastrocnemius nerve was stimulated at 20 times TT. This produced a 90% increase in ventilation. Stimulation of either nerve resulted in increases in the activity of the right diaphragm, parasternal intercostal and alae nasi muscles comparable in magnitude to the increase in tidal volume. The activities of the genioglossus and transversus abdominis muscle increased to a much greater extent than did the other muscles under all conditions. In contrast, triangularis sterni activity remained unchanged during stimulation of either nerve. The phrenic nerve was then stimulated at 40 times TT for 1 min with superimposed gastrocnemius nerve stimulation (20 times TT) during the last 30 s. Ventilation had risen by 66% after 30 s of phrenic nerve stimulation. With the addition of gastrocnemius nerve stimulation, ventilation rose by a further 84% for a total increase of 150% of the control value. Mathematical summation of the responses to individual nerve stimulation at these intensities predicted a 156% increase in ventilation. Similar degrees of summation were found with respect to respiratory muscle activation. We conclude that the interaction between phrenic and limb muscle (gastrocnemius) afferent is additive with respect to their effects on ventilation.