Search

Study Design: Systematic review., Objectives: Identify, evaluate, and synthesize evidence regarding the effectiveness of various treatment strategies for the respiratory management of acute tetraplegia., Setting: Melbourne, Australia., Methods: A search of multiple electronic databases (Medline, Cinahl, EMBASE, Cochrane Library, Web of Science, http://www.guideline.gov and http://www.icord.org/scire) was undertaken accompanied by the reference lists of all relevant articles identified. Methodological quality was assessed using the Newcastle-Ottawa Scale and the PEDro Scale. Descriptive analysis was performed., Results: Twenty-one studies including 1263 patients were identified. The majority of the studies were case series (n = 13). A variety of interventions were used for the management of respiratory complications. Mortality (ARR = 0.4, 95% confidence interval (CI) 0.18, 0.61), the incidence of respiratory complications (ARR = 0.36, 95% CI (0.08, 0.58)), and requirement for a tracheostomy (ARR = 0.18, 95% CI (-0.05, 0.4)) were significantly reduced by using a respiratory protocol. A clinical pathway reduced duration of mechanical ventilation by 6 days 95% CI (-0.56, 12.56), intensive care unit length of stay by 6.8 days 95% CI (0.17-13.77) and costs. Intubation, mechanical ventilation, and tracheostomy are the mainstay of respiratory management for complete injuries above the level of C5., Conclusion: This review showed a clinical pathway with a structured respiratory protocol that includes a combination of treatment techniques provided regularly is effective in reducing respiratory complications and cost. The overall study quality was moderate and further studies using specific interventions that target respiratory complications are associated with specific regions of the cervical spine using more methodologically rigorous designs are required.

Background: Diaphragm pacing (DP) can replace mechanical ventilation in tetraplegics and in trials has assisted respiration in amyotrophic lateral sclerosis patients. This report describes results of DP in patients with cardiac pacemakers., Methods: Prospective, single-center and multicenter, nonrandomized, controlled, interventional protocols under U.S. Food and Drug Administration and/or institutional review board approval were evaluated. Patients underwent laparoscopic diaphragm motor point mapping to identify optimal electrode site for implantation. With diaphragm conditioning, patients were weaned from their ventilator. Perioperative and long-term assessments between the cardiac pacemakers and DP were analyzed for any device-to-device interactions., Results: Over 300 subjects were implanted from 2000 to 2010. Twenty tetraplegics with cardiac pacemakers and DP were analyzed from 6 sites. Subjects ranged from 19 to 61 years old with DP implantation 6 months to 24 years postinjury. There were no immediate or long-term device to device interactions. All patients achieved diaphragm-paced tidal volumes exceeding their basal requirements and, after conditioning, all patients could go >4 hours without mechanical ventilators; 71% could go 24 hours continuously., Conclusion: DP can be safely implanted in tetraplegics having cardiac pacemakers. Applications for temporary use of DP to maintain diaphragm type 1 muscle fiber and improve posterior lobe ventilation may benefit complex critical care patients., (Copyright © 2010 Mosby, Inc. All rights reserved.)

(1) The NeuRx DPS is a laparoscopically implanted device that provides ventilatory support. (2) This device stimulates the diaphragm muscle, rather than the phrenic nerve, and is intended to lead to less risk of nerve damage than other therapies.(3) This technology provides an alternative to mechanical ventilation, and allows patients to increase day-to-day freedom and minimize the risk of respiratory infection. (4) The NeuRx DPS safety profile is based on clinical testing, which began with clinical trials starting in 2000. It has the potential to reduce costs, but this has not been well established.

Context: Diaphragm pacing in ventilator-dependent tetraplegic subjects is usually achieved by the placement of phrenic nerve electrodes via thoracotomy. However, this technique may be accomplished less invasively via laparoscopic placement of IM electrodes, at a lower cost and with less risk of injury to the phrenic nerve., Objective: To assess the feasibility of laparascopic placement of IM diaphragm electrodes to achieve long-term ventilatory support in ventilator-dependent tetraplegic subjects., Design, Setting, and Participants: Two IM diaphragm electrodes were placed laparoscopically in each hemidiaphragm in five subjects with ventilator-dependent tetraplegia. Studies were performed either on an outpatient basis or with a single overnight hospitalization. Ventilator-dependent tetraplegic subjects were identified in whom bilateral phrenic nerve function was present, as determined by phrenic nerve conduction studies. Following electrode placement, subjects participated in a conditioning program to improve the strength and endurance of the diaphragm over a period of 15 to 25 weeks. The duration of the study was variable depending on the time necessary to determine the maximum duration that individuals could be maintained without mechanical ventilation support., Main Outcome Measures: Magnitude of inspired volume generation and duration of ventilatory support with bilateral diaphragm pacing alone., Results: In four of the five subjects studied, initial bilateral diaphragm stimulation resulted in inspired volumes between 430 and 1,060 mL. Reconditioning of the diaphragm over several weeks resulted in substantial increases in inspired volumes to 1,100 to 1,240 mL. These subjects were comfortably maintained without mechanical ventilatory support for prolonged time periods by diaphragm pacing, by full-time ventilatory support in three subjects, and 20 h per day, in the fourth subject. No response to stimulation was observed in one subject, most likely secondary to denervation atrophy., Conclusions: Diaphragm pacing in ventilator-dependent tetraplegic subjects can be successfully achieved via laparascopic placement of IM electrodes.

The authors have previously shown that conditioning of the diaphragm for continuous bilateral pacing is a feasible and effective means of ventilation in patients with complete respiratory paralysis from high cervical (above C3) quadriplegia. The present study reports the long-term results of continuous diaphragmatic pacing. Twelve quadriplegia patients underwent bilateral phrenic nerve pacemaker placement and diaphragm conditioning from 1981 to 1987. Pacing was initiated at 11 Hz and progressively decreased to 7.1 Hz. A pulse train duration of 1.3 seconds for adults and 0.9 seconds for children was used. Long-term follow-up information obtained included pacing status (full-time, part-time, or mechanical ventilation), ventilation parameters, and social circumstances. Of the 12 patients, 6 continued to pace full time (mean 14.8 years); all were living at home. Three patients paced for an average of 1.8 years before stopping; two were institutionalized. One patient who paced full time for 6.5 years before lapsing to part time, lived at home. Two patients were deceased; one paced continuously for 10 years before his demise, the other stopped pacing after 1 year. Patients who stopped full-time pacing did so mainly for reasons of inadequate social or financial support or associated medical problems. All patients demonstrated normal tidal volumes and arterial blood gases while pacing full time. Despite theoretical concerns about long-term nerve damage, no patient lost the ability to pace the phrenic nerve. Threshold currents did not increase over time (original/follow-up: 0.46/0.47 for right, 0.45/0.46 for left), nor did maximal currents (original/follow-up: 1.16/1.14 for right, 1.37/1.26 for left). This follow-up confirms that quadriplegic patients are able to meet long-term, full-time ventilation requirements using phrenic nerve stimulation of the conditioned diaphragm. Careful review of diaphragmatic pacing candidates with respect to associated medical conditions, social support, and motivation is essential for appropriate patient selection and successful long-term results.

Electrical stimulation has been used for over 25 years to restore breathing to patients with high quadriplegia causing respiratory paralysis and patients with central alveolar hypoventilation. Three groups have developed electrical pacing systems for long-term support of respiration in humans. These systems consist of electrodes implanted on the phrenic nerves, connected by leads to a stimulator implanted under the skin, and powered and controlled from a battery-powered transmitter outside the body. The systems differ principally in the electrode design and stimulation waveform. Approximately 1,000 people worldwide have received one of the three phrenic pacing devices, most with strongly positive results: reduced risk of tracheal problems and chronic infection, the ability to speak and smell more normally, reduced risk of accidental interruption of respiration, greater independence, and reduced costs and time for ventilatory care. For patients with partial lesions of the phrenic nerves, intercostal muscle stimulation may supplement respiration.

Background: Electrophrenic pacing can be used in the management of ventilatory failure in quadriplegic patients. A study was undertaken to determine the pattern of transdiaphragmatic pressure (PDI) during the conditioning phase of electrophrenic pacing to see if it had a possible role in optimising the process of conditioning., Methods: The tidal volume (TV) and PDI were measured in a group of six quadriplegic patients commencing ventilation by low frequency pulse stimulation (7-10 Hz) and low respiratory rate stimulation (< 10 breaths/min)., Results: Tidal volume increased between baseline and month 1 (4.33 ml/kg, p < 0.001) and between months 1 and 2 (3.00 ml/kg, p < 0.05) and then stabilised. PDI was higher during bilateral diaphragmatic pacing (mean (SD) 1.73 (0.30) kPa) than with either left (1.15 (0.34) kPa) or right (0.86 (0.37) kPa) unilateral pacing. PDI varied throughout the observation period, probably by interaction between recovery of the diaphragmatic fibres and the pacing regimen., Conclusions: Patients with quadriplegia due to high spinal injury can be maintained with ventilation by continuous electrophrenic pacing. The control criteria used in this study for pacing were tidal volume and the patient's tolerance, and the PDI measurement did not contribute any additional information to help with managing the conditioning process.

Respiratory problems are a major cause of death in the acute and chronic phases of cervical spinal cord injury (CSCI); CSCI paralyzes the intercostal and abdominal muscles, reducing ability to cough and clear secretions. Impaired cough due to neuromuscular disorders can be assessed with the maximum expiratory pressure (MEP). This study consists of two experiments with CSCI patients. In the first, MEP measurements were recorded with the following maneuvers performed: (1) spontaneous cough attempts, (2) manually assisted cough, and (3) cough attempts with functional electrical stimulation (FES) applied to the abdominal wall. In the second, spontaneous cough attempts and cough attempts with a portable FES unit were recorded. These CSCI patients were found to have a greatly reduced MEP when they coughed spontaneously. Either FES-assisted or manually assisted coughing increased the MEP in all patients studied. By increasing the MEP, abdominal muscle FES could enhance cough in quadriplegics.

Electrical stimulation of the phrenic nerve to pace the diaphragm in patients with chronic ventilatory insufficiency has been an established therapeutic modality since William W.L. Glenn first described using radiofrequency signals in 1978 to stimulate the phrenic nerves. Before this event, patients who were ventilator-dependent and thus bedridden because of respiratory paralysis associated with quadriplegia usually anticipated little chance for physical or psychosocial rehabilitation. Two cases of C1-C2 subluxtion with cord injury and chronic ventilatory insufficiency were implanted at VGH-Taipei with diaphragm pacemaker in 1988. Postoperative phrenic nerve stimulation was given according to individual training schedule. One case with total phrenic paralysis received bilateral phrenic nerve stimulation and became weaned from the ventilator 6 months later. The other case with partially active ventilatory function received unilateral phrenic nerve stimulation to compensate the ventilation. However, its final outcome still showed the necessity of a bilateral mode to achieve adequate ventilation irrespective of strenuous training for 2 years.

Resting tidal volume and vital capacity were measured daily in 5 patients with acute quadriparesis during the first 7 to 10 days of their hospitalisation. On admission, vital capacity was significantly reduced to 26% of the predicted value (p less than 0.001). This increased significantly over the study period to 33% of the predicted value (p less than 0.02). Expiratory flow rates, measured on one occasion during the study period, showed similar decrements. Tidal volume and vital capacity were also measured immediately following administration of intermittent positive pressure breathing (IPPB). Although the lung volume achieved during IPPB was significantly higher than resting values of tidal volume and vital capacity (p less than 0.001), tidal volume returned to baseline values as soon as IPPB was ceased. Vital capacity remained significantly higher than baseline values at this stage (p less than 0.02), although the mean increase in vital capacity immediately following IPPB was only 43 mls. Acute quadriparesis is associated with a severe ventilatory impairment which includes a reduced vital capacity and expiratory flow rates. IPPB has a positive effect on lung volume whilst it is being administered. Immediately following treatment, this effect does not appear to be sustained at a level which would be considered clinically significant.

We provided full-time ventilatory support in five patients with respiratory paralysis accompanying quadriplegia by continuous electrical pacing of both hemidiaphragms simultaneously for 11 to 33 months through the application to the phrenic nerves of a low-frequency stimulus. The strength and endurance of the diaphragm muscle increased with pacing. Biopsy specimens taken from two patients who had uninterrupted stimulation for 6 and 16 weeks showed changes suggestive of the development of fatigue-resistant muscle fibers. When we compared these results with those of our earlier experience with intermittent unilateral stimulation of the diaphragm in 17 patients with respiratory paralysis, we found that continuous bilateral pacing using low-frequency stimulation appeared to be superior because of more efficient ventilation of both lungs, fewer total coulombs required to effect the same ventilation, and absence of myopathic changes in the diaphragm muscle. For patients with respiratory paralysis and intact phrenic nerves, continuous simultaneous pacing of both hemidiaphragms with low-frequency stimulation and a slow respiratory rate is a satisfactory method of providing full-time ventilatory support.

Thirty-seven quadriplegic patients with respiratory paralysis were treated by electrical stimulation of the phrenic nerves to pace the diaphragm. Full-time ventilatory support by diaphragm pacing was accomplished in 13 patients. At least half-time support was achieved in 10 others. There were two deaths unrelated to pacing in these two groups. Fourteen patients could not be paced satisfactorily, and 8 of these patients died, most of them from respiratory infections. The average time the 13 patients on total ventilatory support have had bilateral diaphragm pacemakers is 26 months. The longest is 60 months. Many of these patients are out of the hospital and several are in school or working. Injury to the phrenic nerves either by the initial trauma to the cervical cord or during operation for implantation of the nerve cuff was the most significant complication. Nerve damage from prolonged electrical stimulation has not been a problem thus far. A description of the pacemaker, the technique of its implantation, and the pacing schedule are reported.

Three children, aged 6-10 years, in whom cervical cord injury at the C1-C2 level resulted in apnoea had bilateral implantation of diaphragm pacemakers. With periods of gradual conditioning of the diaphragm muscle to low frequency stimulation and slow respiratory rates they adapted to continuous ventilatory support by simultaneous stimulation of both hemidiaphragms without evidence of fatigue, so far for periods of 23-47 months.

Although a few reports of phrenic nerve stimulation have appeared over the past dozen years, electromyographers have not readily accepted these methods. Perhaps this is because the techniques are considered unreliable, or because there is a major element of patient discomfort. In this study a simple, safe, and relatively painless procedure was devised for placing a needle near the phrenic nerve for use as a stimulating electrode. Also, the positions of the recording electrodes were relocated until a site was found that consistently provided a response with an initial negative deflection in all subjects. Emphasis has been on improving technique. A group of 60 nerves in 30 normal subjects was studied. The mean latency was 7.44 +/- 0.59msec, and the mean difference between right and left was 0.08 +/- 0.42msec. A response was obtained in all nerves examined. In addition, 13 patients with quadriplegia due to spinal cord injury were studied. This method now permits reliable analysis of localized phrenic nerve lesions and abnormalities induced in either the phrenic nerve or diaphragm by generalized disease processes.

Despite increased alveolar ventilation, positive-pressure ventilation (PPV) reproducibly resulted in less efficient arterial oxygenation as compared to diaphragmatic pacing in a quadriplegic patient with respiratory paralysis. Volume loading acutely restored arterial oxygenation during PPV. This report emphasizes the important interaction between the cardiovascular and pulmonary systems in effecting gas exchange, particularly in quadriplegics. In this respect, diaphragmatic pacing seems to perform better than PPV.

The authors report a case of post traumatic tetraplegia at the C1-C2 level in a young man of 16 with total respiratory paralysis treated with mechanical ventilation and a tracheotomy. Thirty months after the accident, an Avery S 232(1) diaphragmatic pacemaker was surgically implanted by the mediastinal approach. The technique was rapidly successful and enabled satisfactory ventilation and phonation two months after the implantation. The patient is currently treated at home with no signs of diaphragmatic fatigue 20 months after the implantation of the stimulator.

A case of a 20-year-old woman who survived respiratory quadriplegic state and then became to be a candidate for rehabilitation is reported. The patient was injured in an automobile accident and immediately developed cardiopulmonary arrest, quadriplegia and maximum mydriasis bilaterally. She was transferred to our hospital six minutes after the accident. Immediate and appropriate resuscitation could bring restoration of only cardiac contractions without spontaneous breathing and minimal movement of extremities. Skull and cervical spine x-rays showed anterior atlanto-axial dislocation with a fracture of dens in addition to a linear skull fracture in the right temporoparietal region. Traction by Glisson's method was applied initially three and a half hours after the accident under controlled ventilation with a respirator. Five days after the onset, her consciousness became clear and she displayed an onionskin pattern of anesthesia with sensory preservation around her mouth and nose. Subsequently quadriplegia gradually improved from the lower extremities to the upper, however the proximal muscles of the upper extremities remained to be involved for a long period of time. The authors speculated that such a peculiar pattern of paralysis was due to the injury of the rostral part of the pyramidal decussation and to the acute central cord injury at the C2 level of the spinal cord. Halo-vest immobilization technique was applied and active postural drainage was done as the treatment of the respiratory quadriplegia. She could wean off the respirator four months after the onset and became independent in her active daily living six months after the accident.(ABSTRACT TRUNCATED AT 250 WORDS)