Diaphragm Pacing


Concerned population

Tetraplegia or cervical cord injury

CCHS

ALS

Intensive care unit

Adults/children

Adults/children

Intervention being studied

Diaphragm pacing

Phrenic nerve pacing

Diaphragm stimulation

//

Control population of patients

Patients under mechanical ventilation

Spontaneous evolution in ALS

Ventilated tetraplegic patients

//

Analyzed criteria in outcomes

Mortality

Number of patients weaned from ventilator

Quality of life

Time for mechanical ventilation in ALS

Morbidity

Early and long-term survival

(Mobility, speech, smell, taste)

Phrenic nerve injury


Abbreviations: ALS amyotrophic lateral sclerosis, CCHS Congenital Central Hypoventilation Syndrome.





Results


The exact number of DP implanted all over the world is not well known but is probably less than 5,000 procedures having been performed since the first implanted tetraplegic patient [1].


Cervical or Thoracic Approach for DP


The first available device was an RF system including an implanted internal component—Platinum electrodes surrounding the phrenic nerve connected to the subcutaneous receiver—and an external component—an antenna stitched on the skin facing the receiver connected to the battery-powered transmitter. The initial concept was alternate-side pacing because bilateral high-frequency pacing was not well tolerated, resulting in diaphragm fatigue. The introduction of low-frequency pacing after a reconditioning period allowed continuous bilateral stimulation [2]. The first and largest international study was reported by Glenn in 1988 [3]. It included 477 implanted patients with detailed data and complete follow-up reported for 165 patients. The indication for DP was primarily medullar injury (Table 37.2). The goal of ventilator weaning (full or part time) was achieved in 84.24 % of patients. In summary, some ventilator-dependent patients following central respiratory paralysis can be weaned from their ventilator after the implantation of a Diaphragm Pacing. Standardized neuromuscular tests are recommended to select patients for diaphragm pacing.


Table 37.2
Series of diaphragm pacing









































































































































Authors (year)

N

Series

Type of study

Ratio children/adult/NA

Indications (%)

Approach

Types of electrodes

Mode of pacing

Implant

Thoracic or cervical approach

Glenn et al. [3] (1988)

477

MultiC

R

NA

CSCI (46)a

NA/CT

BiP

Mainly U

InterN
   
Brain stem (28.3)a
 
MonoP
 

Idiopathic (13)a
   

Congenital (9.5)a

Peripheral (3.3)a

Weese Mayer et al. [4] (1996)

64

MultiC

Q

35/24

CSCI

4 C

QuadriP

60 B

InterN

CCHS

60 T

4 U

Hirschfeld et al. [10] (2008)

64

64

P

NA

CSCI

NA/CT

QuadriP

NA

Khong et al. [10] (2010)

19

MonoC

R

4/13/2

14 CSCI

10 C

MonoP
 

1 CCHS

6 T

15 B

1encephalithis

3 NA

2 U

3 NA

2 NA

Le Pimpec-Barthes et al. [6] (2011)

20

MonoC

R

10/10

19 CSCI

20 T

QuadriP

20 B

1 CCHS

Ponikowski et al, [16] (2012)

16

MultiCInterN

P

0/16

Sleep Central Apnea

Transvenous

Endovascular

16 B

Laparoscopic approach

Onders et al. [12] (2009)

88

MultiC

P

All adults

50 CSCI

Abd

Intra diaphragmatic

88 B

InterN

38 ALS


Legends: N number of patients, MultiC Multicentric, MonoC Monocentric, R Retrospective, P prospective, Q questionnaire, InterN International, C cervical approach, T Thoracic approach, NA not available, Bilat Bilateral, UniL Unilateral, CSCI Cervical spinal cord injury, CCHS Congenital Central Hypoventilation Syndrome, QuadriP Quadripolar, MonoP Monopolar, Abd abdominal

aAmong 477 patients, 368 had available data

Failure to pace, in 15.76 % of cases, was mainly related to lack of indications for pacing but also to phrenic nerve injuries during the surgical procedure or to local complications (infection) after the procedure. Thoracic implantation of monopolar electrodes was associated with the lowest risk of nerve injury and local complications (less electrode breakage and local infections) compared to implantation at a cervical level. In 17 patients, an incorrect indication of pacing was retrospectively identified, leading to 82.86 % pacing failure among them. When considering good indications for pacing, the rate of failure decreased to 6.06 %. Definite peripheral phrenic nerve damage is a contraindicate diaphragm pacing.

The long-term follow-up demonstrated that about 64 % of paced patients were living at home at the time they died or when this survey was done; of those who were still paced, 82 % required no or minimal supplemental support. Concerning their activity level, before death or at the termination of this study, about 42 % were working, going to school or were normally or moderately active. The removal of tracheostomies was analyzed: in the 32 cases in which closure was achieved, 75 % of tracheostomies were reopened leading the authors to recommend keeping the tracheostomy intact (often closed with a button). In tetraplegic patients with full-time pacing, keeping the tracheostomy in place with a tracheal button is recommended. The number of years with pacing was up to 5 years in 263 patients, 5–10 years in 55 patients, 10–15 years in 17 patients and 15–20 years in four patients. In summary, bilateral diaphragm pacing gives excellent long-term results up to 20 years of active pacing.

The retrospective international study reported by Weese-Mayer included 35 children and 29 adults implanted with the quadripolar phrenic pacing system (Jukka Atrotech® Tampere, Finland) [4] (Table 37.2). DP was successful in 94 % of pediatric patients and 86 % of adult patients. Successful pacing with no complication occurred in 56 % of patients (60 % in children and 52 % adults). Morbidity included local infection in 11.4 % of pediatric patients (none in adults, total rate of 6.3 % for all patients) and 3.8 % of phrenic nerve injuries. Electrode and receiver failure was reported in 3.1 % of patients with tetraplegia and 5.9 % with CCHS (P < 0.01). At a mean follow-up of 2.2 years, 95 % of patients were alive and the three deaths observed were independent from DP. This study showed that the incidence of postoperative complications was higher in pediatric patients with CCHS even though pacing complications did not increase among pediatric compared to adult patients. In summary, TDP results in full-time or part-time weaning from a ventilator in 89 % of adults and children. Compared to adult patients, a higher risk of infection is reported after DP in pediatric patients.

In 2010, the Australian experience was reported by Khong et al. [5]. This retrospective study included 19 paced patients, mainly for tetraplegia (74 %). CTP (n = 11) and TDP (n = 6, all bilateral) were used depending on the surgeon’s preferences (Table 37.2). Avery Biomedical devices with a monopolar electrode (Commack, NY, USA) were used. Eight patients required reoperation for partial replacement; in four cases it was necessary because the original receiver had a 3–5 year lifetime, in three cases the reason was a device failure and in one case the reason was unknown. In later years of the study, the newer receivers had a longer lifetime. Eleven patients were still actively implanted with total pacing duration ranging from 1–21 years. Currently, new DP devices are available allowing long-term stimulation without the need for redo-surgical procedures.

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Dec 30, 2016 | Posted by in CARDIOLOGY | Comments Off on Diaphragm Pacing
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