Diaphragmatic muscle function in term and preterm infants.

We aimed to assess the determinants of diaphragmatic function in term and preterm infants. 149 infants (56 term; 93 preterm, of whom 14 were diagnosed with bronchopulmonary dysplasia-BPD) were studied before discharge. Diaphragmatic function was assessed by measurement of the maximum transdiaphragmatic pressure (Pdimax)-a measure of diaphragmatic strength, and the pressure-time index of the diaphragm (PTIdi)-a measure of the load-to-capacity ratio of the diaphragm. The Pdimax was higher in term than preterm infants without BPD (90.1 ± 16.3 vs 81.1 ± 11.8 cmH2O; P = 0.001). Term-born infants also had lower PTIdi compared to preterms without BPD (0.052 ± 0.014 vs 0.060 ± 0.017; P = 0.006). In term and preterm infants without BPD, GA was the most significant predictor of Pdimax and PTIdi, independently of the duration of mechanical ventilation and oxygen support. In infants with GA < 32 weeks (n = 30), the Pdimax was higher in infants without BPD compared to those with BPD (76.1 ± 11.1 vs 65.2 ± 11.9 cmH2O; P = 0.015). Preterms without BPD also had lower PTIdi compared to those with BPD (0.069 ± 0.016 vs 0.109 ± 0.017; P < 0.001). In this subgroup, GA was the only significant independent determinant of Pdimax, while BPD and the GA were significant determinants of the PTIdi.  Conclusions: Preterm infants present lower diaphragmatic strength and impaired ability to sustain the generated force over time, which renders them prone to diaphragmatic fatigue. In very preterm infants, BPD may further aggravate diaphragmatic function. What is Known: • The diaphragm of preterm infants has limited capacity to undertake the work of breathing effectively. • The maximum transdiaphragmatic pressure (a measure of diaphragmatic strength) and the pressure-time index of the diaphragm (a measure of the load-to-capacity ratio of the muscle) have not been extensively assessed in small infants. What is New: • Preterm infants have lower diaphragmatic strength and impaired ability to sustain the generated force over time, which renders them prone to diaphragmatic fatigue. • In very preterm infants, bronchopulmonary dysplasia may further impair diaphragmatic function.

Comparison of Changes in Chest Wall Mechanics and Respiratory Timing Between Patient-Controlled Epidural Analgesia and Intravenous Patient-Controlled Analgesia After Laparoscopic Gastrectomy: A Randomized Controlled Trial.

BACKGROUND: Upper abdominal surgery is associated with postoperative diaphragmatic dysfunction. Whether patient-controlled epidural analgesia (PCEA) is superior to intravenous patient-controlled analgesia (IV-PCA) in preventing postoperative diaphragmatic dysfunction is still unclear in laparoscopic gastric surgery. METHODS: Sixteen patients undergoing laparoscopic gastrectomy randomly received either PCEA or IV-PCA. The primary outcomes were the change in chest wall mechanics and respiratory timing, measured by respiratory inductive plethysmography (Respitrace; Ambulatory Monitoring Inc., Ardsley, New York, United States) before and after surgery, and analyzed by a data acquisition system (PowerLab; ADInstruments, Dunedin, New Zealand). Inspiratory time (Ti), expiratory time (Te), total respiratory cycle time (Ttot), proportion of inspiratory time over total respiratory cycle time (Ti/Ttot), respiratory rate (RR), and abdominal contribution to tidal volume (AB/VT [%]) were calculated from the stored data. AB/VT, relative volume contribution of diaphragm to tidal breathing, represents an index of diaphragmatic function. Because the diaphragm is the main contributor to tidal volume, decreases in AB/VT indicate diaphragm dysfunction. Changes in outcomes over time between the two groups were analyzed using a linear mixed model, and two-sided p values < 0.05 were considered statistically significant. The secondary outcomes were postoperative pain score (visual analog scale (VAS)), bowel function recovery, and hospital stay duration. RESULTS: Postoperative AB/VT in the IV-PCA group was significantly decreased compared to preoperative levels. AB/VT in the PCEA group was significantly higher than the IV-PCA group on postoperative day (POD) 1. Change in AB/VT over time between the PCEA group and the IV-PCA group differed significantly (p = 0.01). A decrease of AB/VT during POD 1 to 3 was observed in the IV-PCA group but not in the PCEA group. As for respiratory timing, there were significant increases in RR with a reduction of Te and Ttot compared to preoperative levels on POD 1 in the PCEA group. There were significant decreases in RR and Ti/Ttot with an increase of Te and Ttot compared to preoperative levels on POD 1 in the IV-PCA group. There was a significant difference in the change of the Ttot over time between the two groups (p = 0.046). There were no significant differences in the changes of Te, Ti/Ttot, Ti, and RR over time between the two groups. There was no significant difference in VAS over time at rest and mobilization, recovery of bowel function, and hospital stay between the two groups. CONCLUSIONS: Continuous ropivacaine infusion with PCEA partially attenuated diaphragmatic dysfunction after laparoscopic gastrectomy, while pain relief by continuous intravenous administration of fentanyl could not attenuate diaphragmatic dysfunction. This suggests that PCEA might ameliorate postoperative diaphragmatic dysfunction after laparoscopic gastrectomy.

Impact of intubated vs. non-intubated anesthesia on postoperative diaphragmatic function: Results from a prospective observational study.

Background: An altered diaphragmatic function was associated with the development of postoperative pulmonary complications following thoracic surgery. Methods: To evaluate the impact of different anesthetic techniques on postoperative diaphragmatic dysfunction, patients undergoing video-assisted thoracoscopic surgery (VATS) lung biopsy for interstitial lung disease were enrolled in a monocentric observational prospective study. Patients received intubated or non-intubated anesthesia according to risk assessment and preferences following multidisciplinary discussion. Ultrasound measured diaphragmatic excursion (DIA) and Thickening Fraction (TF) were recorded together with arterial blood gases and pulmonary function tests (PFT) immediately before and 12 h after surgery. Pain control and postoperative nausea and vomiting (PONV) were also evaluated. Results: From February 2019 to September 2020, 41 consecutive patients were enrolled. Five were lost due to difficulties in collecting postoperative data. Of the remaining 36 patients, 25 underwent surgery with a non-intubated anesthesia approach whereas 11 underwent intubated general anesthesia. The two groups had similar baseline characteristics. On the operated side, DIA and TF showed a lower residual postoperative function in the intubated group compared to the non-intubated group (54 vs. 82% of DIA and 36 vs. 97% of TF; p = 0.001 for both). The same was observed on the non-operated side (58 vs. 82% and 62 vs. 94%; p = 0.005 and p = 0.045, respectively, for DIA and TF). No differences were observed between groups in terms of pain control, PONV, gas exchange and PFT. Conclusion: This study suggests that maintenance of spontaneous breathing during VATS lung biopsy is associated with better diaphragmatic residual function after surgery.

Application value of bedside ultrasound assessment of diaphragmatic dysfunction in sepsis patients / 中华急诊医学杂志

Objective:To evaluate the risk factors for diaphragmatic dysfunction of patients with sepsis and septic shock, and the application value of bedside ultrasound.Methods:Patients with sepsis and septic shock in the Intensive Care Unit (ICU), General Hospital of Ningxia Medical University from January 2020 to May 2021 were prospectively recruited as the research subjects, general postoperative patients and healthy volunteers were admitted as postoperative control and normal control groups. General clinical data were collected, patients with sepsis and septic shock were dynamically observed high sensitive c-reactive protein (hs-CRP), interleukin-6 (IL-6), serum albumin, transferrin, prealbumin levels, blood lactate, Pcv-aCO 2, ScvO 2, etc.; and indirect calorimetry was used to measure the resting energy level of the patient to calculate the missing energy value. Bedside ultrasound was used to dynamically evaluate the changes of diaphragm excursion (DE),inspiratory diaphragm thickness, and expiratory diaphragm thickness, to calculate relevant parameters. DE<10 mm or diaphragmatic thickness fraction (DTF) < 20% was diagnosed as diaphragmatic dysfunction. Results:(1) On day 1 in the ICU, the DE of the septic shock group, sepsis group and postoperative control group were significantly lower than that in the normal control group [10.3 (9.0, 13.6) mm, 12.3 (9.1, 15.0) mm, 12.9 (10.5, 15.7) mm vs. 22.0 (16.0, 24.6) mm, all P<0.05], and the incidence of DTF<20% was significantly higher than in the normal control group (32.7%, 41.9%, 33.3% vs. 0 %, all P<0.05), and the incidence of DE<10 mm in the septic shock group and sepsis group was significantly higher than that of postoperative control group and normal control group (36.7%, 35.5% vs. 10.0%, 0%, respectively, all P<0.05). On day 7, the DE in the septic shock group was significantly lower than that in the sepsis group [10.5 (6.8, 13.5) mm vs. 14.4 (10.6, 18.6) mm, P<0.05].(2) Correlation analysis of each index: The DE of patients with sepsis and septic shock on day 1, 3, and 7 was negatively correlated with the hs-CRP ( r=-0.253, -0.436, -0.455, all P<0.05); On day 3, DE was also negatively correlated with IL-6 ( r=-0.338, P=0.009); and DTF was negatively correlated with hs-CRP ( r=-0.375, P=0.004). On day 1, there was a positive correlation between DTF and serum transferrin levels in patients with sepsis and septic shock ( r=0.221, P=0.049). On day 3 and 7, the DE was positively correlated with serum prealbumin levels ( r=0.318, 0.408, both P<0.05). Conclusions:Patients with sepsis and septic shock have developed diaphragmatic dysfunction on day 1 in the ICU, which is mainly manifested as decreased in diaphragm mobility and diaphragmatic thickness fraction, and is related to inflammation and high protein catabolism.

A Novel Thoracic Ultrasound Measurement After Congenital Diaphragmatic Hernia Repair Identifies Decreased Diaphragmatic Excursion Associated With Adverse Respiratory and Surgical Outcomes.

Background and Aim: Congenital diaphragmatic hernia (CDH) is a rare defect often associated with pulmonary hypoplasia and abnormal pulmonary vascular development. Even after successful hernia repair, pulmonary disease may persist into adulthood. Impaired diaphragmatic motility may lead to compromised respiratory function long after index repair. This study investigates whether a novel ultrasound measurement, the diaphragmatic excursion ratio, can be a simple and non-invasive method to evaluate routine diaphragmatic motion after CDH repair, and whether it correlates with adverse surgical and respiratory outcomes. Materials and Methods: A cross-sectional study was conducted in consecutive patients who presented at medium-term follow-up visit between December 2017 and December 2018 after CDH repair at single pediatric hospital. Transthoracic ultrasound was performed with craniocaudal diaphragmatic excursion measured bilaterally during routine breathing. Diaphragmatic excursion ratios (diaphragmatic excursion of repaired vs. unrepaired side) were calculated and retrospectively compared with clinical data including demographics, length of stay, respiratory adjuncts, oral feeding, and need for gastrostomy. Results: Thirty-eight patients (median age at ultrasound, 24 months, interquartile range 11-60) were evaluated. Nine patients underwent primary repair, 29 had non-primary repair (internal oblique muscle flap or mesh patch). Patients with a diaphragmatic excursion ratio below the median (0.54) had longer hospital stays (median 77 vs. 28 days, p = 0.0007) more ventilator days (median 16 vs. 9 days, p =0.004), and were more likely to have been discharged on oxygen (68 vs. 16%, p = 0.001). They were also less likely to be exclusively taking oral feeds at 1-year post-surgery (37 vs. 74%, p = 0.02) and more likely to require a gastrostomy tube in the first year of life (74 vs. 21%, p = 0.003). Conclusions: Transthoracic ultrasound after CDH repair is practical method to assess diaphragm motion, and decreased diaphragm excursion ratio is associated with worse respiratory outcomes, a longer length of stay, and dependence on gastrostomy tube feeding within 1 year. Further prospective studies may help validate this novel ultrasound measurement and offer prognostic value.

Neurally adjusted ventilatory assist after surgical treatment of intracerebral hemorrhage: a randomized crossover study.

OBJECTIVE: We assessed the neuromechanical efficiency (NME), neuroventilatory efficiency (NVE), and diaphragmatic function effects between pressure support ventilation (PSV) and neutrally adjusted ventilatory assist (NAVA). METHODS: Fifteen patients who had undergone surgical treatment of intracerebral hemorrhage were enrolled in this randomized crossover study. The patients were assigned to PSV for the first 24 hours and then to NAVA for the following 24 hours or vice versa. The monitored ventilatory parameters under the two ventilation models were compared. NME, NVE, and diaphragmatic function were compared between the two ventilation models. RESULTS: One patient's illness worsened during the study. The study was stopped for this patient, and intact data were obtained from the other 14 patients and analyzed. The monitored tidal volume was significantly higher with PSV than NAVA (487 [443-615] vs. 440 [400-480] mL, respectively). NME, NVE, diaphragmatic function, and the partial pressures of arterial carbon dioxide and oxygen were not significantly different between the two ventilation models. CONCLUSION: The tidal volume was lower with NAVA than PSV; however, the patients' selected respiratory pattern during NAVA did not change the NME, NVE, or diaphragmatic function.Clinical trial registration no. ChiCTR1900022861.

[Effect of electroacupuncture on diaphragmatic function in patients with post-stroke tracheotomy].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on diaphragmatic function based on conventional treatment in patients with post-stroke tracheotomy tube. METHODS: A total of 70 patients were randomized into an observation group (35 cases) and a control group (34 cases, 1 case dropped off). Internal medical basic treatment and breathing training were given in both groups. Besides, Xingnao Kaiqiao acupuncture was applied at Neiguan (PC 6), Shuigou (GV 26), Sanyinjiao (SP 6), Jiquan (HT 1), Chize (LU 5) and Weizhong (BL 40) in the control group, the needles were sustained for 30 min. On the basis of treatment in the control group, EA was applied at Tianding (LI 17), Fengchi (GB 20) and Jiaji (EX-B 2, C3-C5 ) in the observation group, with continuous wave, 10-20 Hz, 30 min each time. The treatment was given once a day, 6 times a week for 4 weeks in both groups. Before and after treatment, the diaphragmatic motility was measured by SonoSite ultrasound system (M-Turbo) in the two groups. RESULTS: Compared before treatment, the diaphragmatic motility after treatment was increased in both groups (P<0.01), and the improvement in the observation group was superior to the control group (P<0.01). CONCLUSION: Electroacupuncture can promote the recovery of diaphragmatic function in patients with post-stroke tracheotomy tube.

Evaluación de los músculos respiratorios en la parálisis diafragmática bilateral / Assessment of respiratory muscle strength in bilateral diaphragmatic paralysis

Measurement of respiratory muscle strength is useful in order to detect respiratory muscle weakness and to quantify its severity. Apropos of a patient with bilateral diaphragmatic paralysis, we review the clinical manifestations and methods for assessing the strength of the respiratory muscles. In patients with severe respiratory muscle weakness, vital capacity and total lung capacity are reduced but are a non-specific and relatively insensitive measure. Conventionally, inspiratory and expiratory muscle strength has been assessed by maximal inspiratory and expiratory mouth pressures sustained for one second (PIMax and PEMax). The sniffmanoeuvre is natural and probably easier to perform. Sniff pressures are more reproducible and useful measure of diaphragmatic strength. However, the PIMax-PEMax and sniff manoeuvres are volition dependent, and submaximal efforts are most likely to occur in patients who are ill or breathless. Non-volitional tests include measurements of twitch esophageal, gastric and transdiaphragmatic pressure during bilateral electrical and magnetic phrenic nerve stimulation. Electrical phrenic nerve stimulation is technically difficult and is also uncomfortable and painful. Magnetic phrenic nerve stimulation is less painful and transdiaphragmatic pressure is reproducible in normal subjects. Systematic clinical evaluation and additional laboratory tests allow the diagnosis in most patients with respiratory muscle weakness.

La evaluación de la fuerza de los músculos respiratorios permite diagnosticar y cuantificar la gravedad de la debilidad muscular en diferentes enfermedades. A propósito de un paciente con parálisis diafragmática bilateral, hemos revisado el cuadro clínico y los procedimientos diagnósticos para evaluar la fuerza de los músculos respiratorios. En los pacientes con debilidad muscular respiratoria severa, disminuye la capacidad vital y la capacidad pulmonar total, pero es una medida inespecífica y relativamente insensible. Tradicionalmente, la fuerza muscular respiratoria es evaluada midiendo la presión inspiratoria y espiratoria máximas en la boca sostenidas durante un segundo (PIMax y PEMax). La medición de la presión inspiratoria máxima en la nariz (SNIP) es una maniobra natural, más simple de medir y más reproducible, siendo útil en la evaluación de la fuerza diafragmática. Sin embargo, estas técnicas no invasivas son operador dependiente, por lo tanto, esfuerzos submáximos es más probable que ocurran en pacientes graves o con disnea. Las mediciones de las presiones esofágica, gástrica y transdiafragmática mediante estimulación eléctrica o magnética del nervio frénico no son dependientes de la voluntad y son más confiables. Sin embargo, la estimulación eléctrica del nervio frénico es técnicamente difícil y puede ser incómoda y dolorosa. La estimulación magnética del nervio frénico es menos dolorosa y la medición de la presión transdiafragmática es reproducible en sujetos normales. La evaluación clínica sistemática y los exámenes de laboratorio complementarios permiten establecer el diagnóstico en la mayoría de los pacientes con debilidad de los músculos respiratorios.