Evaluation of the respiratory muscle strength of cirrhotic patients: relationship with Child-Turcotte-Pugh scoring system

The use of tracheostomy to support critically ill children receiving orthotopic liver transplantation: a single-center experience

BACKGROUND

Children with end-stage liver disease and multi-organ failure, previously considered as poor surgical candidates, can now benefit from liver transplantation (LT). They often need prolonged mechanical ventilation (MV) post-LT and may need tracheostomy to advance care. Data on tracheostomy after pediatric LT are lacking.

METHOD

Retrospective chart review of children who required tracheostomy in the peri-LT period in a large, freestanding quaternary children's hospital from 2014 to 2019.

RESULTS

Out of 205 total orthotopic LTs performed in 200 children, 18 (9%) required tracheostomy in the peri-transplant period: 4 (2%) pre-LT and 14 (7%) post-LT. Among those 14 needing tracheostomy post-LT, median age was 9 months [IQR = 7, 14] at LT and 10 months [9, 17] at tracheostomy. Nine (64%) were infants and 12 (85%) were cirrhotic at the time of LT. Seven (50%) were intubated before LT. Median MV days prior to LT was 23 [7, 36]. Eight (57%) patients received perioperative continuous renal replacement therapy (CRRT). The median MV days from LT to tracheostomy was 46 [33, 56]; total MV days from initial intubation to tracheostomy was 57 [37, 66]. Four (28%) children died, of which 3 (21%) died within 1 year of transplant. Total ICU and hospital length of stay were 92 days [I72, 126] and 177 days [115, 212] respectively. Among survivors, 3/10 (30%) required MV at home and 8/10 (80%) were successfully decannulated at 400 median days [283, 584].

CONCLUSION

Tracheostomy though rare after LT remains a feasible option to support and rehabilitate critically ill children who need prolonged MV in the peri-LT period.

Surface electromyography for respiratory assessment of liver transplant candidates, healthy subjects and after chevron post-operative incision

BACKGROUND

Surface electromyography is a noninvasive technique for detecting the activity of skeletal muscles and especially the muscles for respiratory compliance; namely, the diaphragm and rectus abdominis. This study compares these muscles in healthy individuals, liver disease patients, and after abdominal surgery.

OBJECTIVE

To study muscle activity by surface electromyography of the right diaphragm muscles and right rectus abdominis (root means square, RMS), and the manovacuometry muscle strength (maximal inspiratory pressure, MIP; and maximal expiratory pressure, MEP).

RESULTS

We evaluated 246 subjects who were divided into 3 groups: healthy (65), liver disease (171), and post-surgery (10). In liver disease group the BMI was higher significantly for ascites (P = .001), and was increase in RMS rectum (P = .0001), RMS diaphragm (P = .030), and a decreased inspiratory and expiratory indices (P = .0001) pressure in the post-surgery group. A multivariate analysis showed tendency to an increased BMI in liver disease and in the post-surgery groups correlated with an increased RMS rectum and the lower MIP/MEP (P = .11). The receiver operating characteristic curve showed that RMS rectus was capable of discriminating liver disease and post-surgery patients from healthy subjects (area = 0.63; 95% CI 0.549-0.725).

CONCLUSION

The muscle activity of normal individuals is lower than in subjects with deficit muscles because less effort is necessary to overcome the same resistance, observed by surface electromyography and muscle strength.

Dyspnea and respiratory muscle strength in end-stage liver disease

AIM

To investigate the prevalence of chronic dyspnea and its relationship to respiratory muscle function in end-stage liver disease.

METHODS

Sixty-eight consecutive, ambulatory, Caucasian patients with end-stage liver disease, candidates for liver transplantation, were referred for preoperative respiratory function assessment. Forty of these (29 men) were included in this preliminary study after applying strict inclusion and exclusion criteria. Seventeen of 40 patients (42%) had ascites, but none of them was cachectic. Fifteen of 40 patients (38%) had a history of hepatic encephalopathy, though none of them was symptomatic at study time. All patients with a known history and/or presence of co-morbidities were excluded. Chronic dyspnea was rated according to the modified medical research council (mMRC) 6-point scale. Liver disease severity was assessed according to the Model for end-stage liver disease (MELD). Routine lung function tests, maximum static expiratory (Pemax) and inspiratory (Pimax) mouth pressures were measured. Respiratory muscle strength (RMS) was calculated from Pimax and Pemax values. In addition, arterial blood gases and pattern of breathing (VE: minute ventilation; VT: tidal volume; VT/TI: mean inspiratory flow; TI: duration of inspiration) were measured.

RESULTS

Thirty-five (88%) of 40 patients aged (mean ± SD) 52 ± 10 years reported various degrees of chronic dyspnea (mMRC), ranging from 0 to 4, with a mean value of 2.0 ± 1.2. MELD score was 14 ± 6. Pemax, percent of predicted (%pred) was 105 ± 35, Pimax, %pred was 90 ± 29, and RMS, %pred was 97 ± 30. These pressures were below the normal limits in 12 (30%), 15 (38%), and 14 (35%) patients, respectively. Furthermore, comparing the subgroups of ascites to non-ascites patients, all respiratory muscle indices measured were found significantly decreased in ascites patients. Patients with ascites also had a significantly worse MELD score compared to non-ascites ones (P = 0.006). Significant correlations were found between chronic dyspnea and respiratory muscle function indices in all patients. Specifically, mMRC score was significantly correlated with Pemax, Pimax, and RMS (r = -0.53, P < 0.001; r = -0.42, P < 0.01; r = -0.51, P < 0.001, respectively). These correlations were substantially closer in the non-ascites subgroup (r = -0.82, P < 0.0001; r = -0.61, P < 0.01; r = -0.79, P < 0.0001, respectively) compared to all patients. Similar results were found for the relationship between mMRC vs MELD score, and MELD score vs respiratory muscle strength indices. In all patients the sole predictor of mMRC score was RMS (r = -0.51, P < 0.001). In the subgroup of patients without ascites this relationship becomes closer (r = -0.79, P < 0.001), whilst this relationship breaks down in the subgroup of patients with ascites. The disappearance of such a correlation may be due to the fact that ascites acts as a "confounding" factor. PaCO2 (4.4 ± 0.5 kPa) was increased, whereas pH (7.49 ± 0.04) was decreased in 26 (65%) and 34 (85%) patients, respectively. PaO2 (12.3 ± 0.04 kPa) was within normal limits. VE (11.5 ± 3.5 L/min), VT (0.735 ± 0.287 L), and VT/TI (0.449±0.129 L/s) were increased signifying hyperventilation in both subgroups of patients. VT/TI was significantly higher in patients with ascites than without ascites. Significant correlations, albeit weak, were found for PaCO2 with VE and VT/TI (r = -0.44, P < 0.01; r = -0.41, P < 0.01, respectively).

CONCLUSION

The prevalence of chronic dyspnea is 88% in end-stage liver disease. The mMRC score closely correlates with respiratory muscle strength.

Relationship between MELD severity score and the distance walked and respiratory muscle strength in candidates for liver transplantation

The model end-stage liver disease (MELD) severity scoring system is used in the allocation of organs for liver transplantation. However, there is no evidence of its relationship with the functionality and respiratory muscle strength in these patients. The aim of this study was to analyze the correlation of MELD with distance walked and respiratory muscle strength in patients awaiting liver transplantation. We performed a cross-sectional analysis of 24 individuals (16 male and 8 female) with mean age of 51.8 +/- 10.4 years. The MELD score inversely correlated with the 6-minute walking test (6MWT) (r = -0.85; P < .001) and with the maximal inspiratory pressure (MIP) (r = -0.69; P < .001). In addition, there was a correlation between 6MWT and MIP (r = 0.77; P < .001). Thus, MELD scores can be considered to be effective tools to predict the functional capacity and respiratory muscle strength in candidates for liver transplantation.