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At least 19 recordsLinked to original sources
PubMed1977

Diaphragmatic function during immersion.

Diaphragmatic function during immersion to midneck level was studied in upright mongrel dogs, using constant electrophrenic stimulation. Effectiveness of diaphragmatic contraction was analyzed in terms of inspired volume (VT) (with airways open), and change in intrathoracic pressure (Pmus) (with the respiratory system occluded). Hydrostatic compression of the immersed body decreased functional residual capacity (FRC) to 55% base-line value (FRCO), resulting in a 2.8-fold increase in Pmus. In spite of this Pmus increase, VT often decreased during immersion, averaging only 83% VTO (base-line value in air). Hence, immersion was associated with a marked stiffening of the respiratory system. The Pmus increase during immersion persisted after restoration of FRC to FRCO, and was related to diaphragmatic length being greater in water than in air under condition of iso-lung volume. In all, there were three factors affecting diaphragmatic function during immersion: FRC reduction, change in thoracic configuration, and stiffening of the respiratory system.

Animals↗
PubMed2026

Comparison of VCV and PCV-VG modes on diaphragmatic function in diabetic patients undergoing laparoscopic colorectal surgery: a prospective randomized controlled study.

BACKGROUND: Diabetic patients are prone to induce diaphragmatic weakness, which can lead to postoperative pulmonary complications (PPCs). The optimal mechanical ventilation mode may potentially improve postoperative diaphragmatic function. This study evaluates the effects of two ventilation modes under driving pressure-guided ventilation strategy on diaphragmatic function, as assessed by diaphragm thickening fraction (DTF) and diaphragm excursion (DE), in diabetic patients following laparoscopic colorectal surgery. METHODS: Eighty patients diagnosed with Type II diabetes scheduled for elective laparoscopic colorectal surgery, were randomly allocated to either the pressure-controlled volume-guaranteed ventilation (PCV-VG) group (Group P) or the volume-controlled ventilation (VCV) group (Group V) during surgery. The primary outcome was diaphragmatic function assessed during both tidal breathing and maximal inspiratory effort after surgery. Secondary outcomes included intraoperative mechanical power, PPCs, and other complications. RESULTS: A total of eighty patients were included in the final analysis. The averaged area under the curve (AUC) for mechanical power during ventilation was significantly lower in Group P than in Group V (p = 0.002). PCV-VG significantly improved both DE and DTF within the first two days post-surgery (AUCDEtidal: p = 0.088, AUCDTFtidal: p = 0.004, AUCDEmax: p = 0.029, AUCDTFmax: p = 0.017). Postoperative diaphragmatic weakness was less frequent in Group P than in Group V (p = 0.019). However, there was no difference in the incidence of PPCs between the two groups (p = 0.155). CONCLUSION: PCV-VG mode can reduce intraoperative mechanical power, better preserve postoperative diaphragmatic function. However, these improvements did not translate into clinical benefits, as evidenced by the lack of reduction in the incidence of PPCs.

Humans↗
PubMed1992

Effects of endotoxic shock on diaphragmatic function in mechanically ventilated rats.

Diaphragmatic function was investigated in mechanically ventilated rats during endotoxic shock (group E, n = 18) and after saline solution injection (group C, n = 8). Endotoxic shock was produced by a 1-min injection of Escherichia coli endotoxin (10 mg/kg iv) suspended in saline. Diaphragmatic strength was assessed before (T0) and 15 (T15) and 60 (T60) min after injection by measuring transdiaphragmatic pressure (Pdi) generated during bilateral phrenic stimulation at 0.5, 10, 20, 30, 50, and 100 Hz. Diaphragmatic neuromuscular transmission was assessed by measuring the integrated electrical activity of the diaphragm. Diaphragmatic endurance was assessed 75 min after injection from the rate of Pdi decline after a 30-s continuous 10-Hz phrenic stimulation. In 16 additional animals, diaphragmatic glycogen content was determined 60 min after inoculation with endotoxin (n = 8) or 0.9% sodium chloride solution (n = 8). Diaphragmatic resting membrane potential (Em) was measured in 16 additional animals 60 min after endotoxin (n = 8) or saline injection (n = 8). Mean blood pressure decreased from 74 +/- 3 to 53 +/- 6 mmHg at T60 in group E, whereas it was maintained in group C. At T60 Pdi was decreased in group E for frequencies of 50 and 100 Hz and was associated with a decreased diaphragmatic electromyographic activity of 25.3 +/- 2.5 and 26.5 +/- 5.2% for 50- and 100-Hz stimulations, respectively, in comparison with T0 values.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2026

Impact on analgesia, diaphragmatic function, and recovery between erector spinae plane block versus superior trunk block in arthroscopic shoulder surgery: a randomized controlled trial.

BACKGROUND: Effective analgesia and preservation of diaphragmatic function are key considerations in analgesia for shoulder surgery. The superior trunk block provides analgesia with reduced phrenic nerve involvement, while the erector spinae plane block offers minimal impact on diaphragm motion. This randomized controlled trial compared the analgesic efficacy, impact on diaphragmatic motion, and postoperative recovery between the two blocks. METHODS: Sixty patients undergoing arthroscopic shoulder surgery were randomized to receive either erector spinae plane block or superior trunk block. Primary outcomes were postoperative VAS and changes in diaphragmatic excursion. Secondary outcomes included Quality of Recovery-15 (QoR-15) scores, morphine-equivalent consumption, and the handgrip strength motor blockade. RESULTS: The superior trunk block resulted in significantly lower dynamic VAS at 1-h postoperatively (0.1 [0.0, 0.2] vs. 5.7 [4.0, 7.6]; p&#x2009;<&#x2009;0.001) and reduced 24-h morphine consumption (7.8 [2.5, 15.0] mg vs. 12.7 [7.5, 17.3] mg; p&#x2009;=&#x2009;0.038) compared to the erector spinae plane block. However, diaphragmatic excursion was better preserved in the erector spinae plane block group (8.37% &#xb1; 20.7% vs. -20.09% &#xb1; 22.2%; p&#x2009;<&#x2009;0.001), with a lower incidence of partial hemidiaphragm paresis (3.3% vs. 46.7%; p&#x2009;<&#x2009;0.001). At 24&#x2009;h postoperatively, QoR-15 scores were higher in the superior trunk block group (p&#x2009;=&#x2009;0.047), and no patient in either group developed handgrip motor blockade. CONCLUSIONS: Superior trunk block offers superior early postoperative analgesia and better overall recovery, while erector spinae plane block minimizes diaphragmatic impairment. However, the erector spinae plane block may represent an option only in carefully selected patients at high respiratory risk, acknowledging its significantly poorer early analgesic profile.

Humans↗
PubMed1976

[Radiological assessment of diaphragmatic function in operated cases of congenital defects of the diaphragm].

An investigation was undertaken in a series of 10 children operated upon for congenital diaphragmatic defects in regard to the value of simple thoracic X-ray pictures for functional assessment of the repaired diaphragm. The radiographs were taken in forced inspiration as well as in forced expiration and indices were calculated for the mobility of the diaphragm and the costophrenic angle. Moreover, an attempt was made to estimate diaphragmatic contraction by comparing the length of the hemidiaphragm during inspiration and during expiration. The obtained results gave sufficient information for routine investigations of diaphragmatic function and compared well with those of radiocinescopy. An impairment of the mobility of the diaphragm and the costophrenic angle was statistically demonstrated in our follow-up series as compared with a control group of healthy children.

Child↗
PubMed1979

Immersion vs pressure-breathing and diaphragmatic function in the upright position.

In seven anesthetized dogs, immersion in the upright position to mid-neck level (IM) was compared to pressure breathing (PB) under dry conditions during constant-stimulus diaphragmatic contraction (EPS). The comparison was in terms of EPS-induced changes in alveolar pressure under static condition (Pmus); EPS-induced tidal volume (VT); and the VT/Pmus ratio (C'). It was found that at iso-lung volume (V): (a) Pmus was greater in IM than in PB, the difference increased at higher V; (b) VT was greater in IM than in PB, but the VT difference (deltaVT) did not parallel that in Pmus; VT was maximum at a V equal to approximately 90% of FRC in air (FRCd) and decreased below and above this volume; (c) during both IM and PB, the VT-V relationship reflected a biphasic relationship of C' to V and appeared to be inherent to the upright position.

Animals↗
PubMed1978

Plication of the diaphragm for symptomatic phrenic nerve paralysis.

Paralysis of the diaphragm in infants may produce severe respiratory difficulty because of the paradoxic motion of the affected diaphragm and shift of a mobile mediastinum to the contralateral side. Six infants with diaphragmatic paralysis and severe respiratory distress underwent plication of the diaphragm by a simple technique. Five of the six infants had significant improvement in respiratory effort and were ultimately weaned from ventilatory support. One patient with bilateral paralysis had only minimal improvement. Diaphragmatic function returned in two patients after plication. Plication of the diaphragm is a safe and useful procedure to improve ventilation in infants with a paralyzed diaphragm. Since this technique does not prevent return of diaphragmatic function, it should be employed prior to the development of sequelae of prolonged assisted ventilation and sooner if the phrenic nerve is permanently injured.

Diaphragm↗
PubMed1977

Acute supine respiratory failure due to bilateral diaphragmatic paralysis.

This report documents the first known case of bilateral diaphragmatic paralysis following blunt trauma to the chest. The important role of diaphragmatic function in maintaining ventilation, particularly with the patient in the supine position, is illustrated by the reduced total lung capacity, functional residual capacity, and vital capacity. Severe hypoxemia with the patient in the supine position, was markedly improved by elevation of the patient to 30 degree and was further improved by sitting the patient upright. Following an initial period of acute respiratory failure, the patient was managed acceptably by maintaining an elevated position for sleeping until diaphragmatic function returned, about nine months after the injury.

Accidents, Traffic↗
PubMed1979

Influence of ruminal insufflation on pulmonary function and diaphragmatic electromyography in cattle.

In 8 healthy, awake cows with permanent cannulated ruminal fistulas and carotid artery loops, respiratory mechanics, ventilation, and diaphragmatic electrical activity were studied before and during stepwise insufflation of the rumen with air pressure to 40 mm of Hg. We found that ruminal insufflation increased intraperitoneal, intrapleural, and transdiaphragmatic pressures and decreased lung volume and lung compliance. In individual cows with rumen insufflation there was an increase in pulmonary resistance, but this trend was not significant in the group. Peak expiratory flow rate was increased and peak inspiratory flow rate was unchanged. Inspiratory duration (Ti) decidal volume decreased slightly, breathing frequency decreased markedly, and minute volume decreased. When intraruminal pressure reached 40 mm of Hg, arterial partial pressure of carbon dioxide (PaCO2) increased (P less than 0.01) and that of oxygen (PaO2) decreased (P less than 0,01) and arterial blood pH decreased (P less than 0.02). Diaphragmatic electromyographic activity was increased, but mechanical effectiveness of the diaphragm was reduced at increased intraruminal pressures.

Animals↗
PubMed1977

Thoracoabdominal motion in chronic obstructive pulmonary disease.

Studies of thoracoabdominal motion using the respiratory magnetometer were performed in 30 patients with chronic obstructive pulmonary disease. Volume equivalency of thoracic and abdominal deflections was established by using the concepts and methods developed by Konno and Mead. Twenty patients were ambulatory, although disabled, and 10 were in acute respiratory failure and were studied in a respiratory intensive care unit. Five of 20 ambulatory patients and 8 of 10 patients in acute respiratory failure showed inward abdominal motion coincident with outward rib cage motion during inspiration, suggesting ineffective diaphragmatic function. This pattern of thoracoabdominal motion was identical to that seen in 2 high quadriplegics with diaphragmatic paralysis when they were breathing entirely with their neck muscles. Inspiratory ascent of the diaphragm was confirmed fluoroscopically in 3 of the 5 ambulatory patients. Patients showing this pattern were generally severely disabled and had the largest residual volumes. Two abnormal patterns of thoracoabdominal motion were observed during the performance of maximal voluntary ventilation in the ambulatory patients. The first, seen in 9 of 20 patients, was characterized by reciprocal or paradoxical motion of rib cage and abdomen, with increase in rib cage volume associated with decrease in abdominal volume during inspiration. The second pattern, seen in 5 of 20 patients, showed complete disorganization of rib cage and abdominal motion, with no consistent or reproducible pattern. Thus, a significant proportion of patients with disabling chronic obstructive pulmonary disease show abnormalities in thoracoabdominal motion that are observable with the respiratory magnetometer and ofter by simple inspection. Most of these abnormalities suggest malfunction of respiratory muscles, particularly the diaphragm.

Abdomen↗
PubMed1976

Injuries to the phrenic nerve resulting in diaphragmatic paralysis with special reference to stretch trauma.

Traumatic interruption of the phrenic nerve causing diaphragmatic paralysis occurs much more commonly than realized. Patients present with symptoms referable to the respiratory, gastrointestinal, or cardiovascular systems as a result of anatomic displacement of the respective organ (eventration). Symptoms often occur shortly after the injury but may be delayed for many years; consequently, prolonged follow-up of these patients is essential. If patients are symptomatic after trauma, judicious observation is dictated, since many will experience gradual return of normal diaphragmatic function over the succeeding six to twelve months. In those who remain significantly symptomatic, thoracotomy and imbrication of the eventration is a simple and effective surgical procedure.

Adult↗
PubMed1975

Simplified operative technique for the long-segment atypical coarctation of the aorta.

Simplified operative technique for the long-segment atypical coarctation of the aorta was described. The main objective of this technique is to gain quick access to both thoracic and abdominal aorta with minimal blood loss, and preservation of diaphragmatic function. This procedure consists of standard thoracotomy and pararectal incision with an entry into the retroperitoneal space. Long prosthetic graft was anastomosed in an end-to-side fashion to bypass the coarctated aorta. The graft is placed through peripheral circumference of the left hemidiaphragm, where phrenic nerve injury is not likely to occur. This technique was successfully applied to two cases of long-segment atypical coarctation of the aorta due to Takayasu's aortitis. Retroperitoneal placement of the graft prevents fatal hemorrhage due to direct contact with the graft. Contamination with transintestinal exudate can also be avoided. Results of the ten-year follow-up of the similar procedure in the literature is encouraging.

Adult↗
PubMed1978

Bilateral diaphragmatic paralysis with hypercapnic respiratory failure. A physiologic assessment.

Bilateral diaphragmatic paralysis was suspected in a patient presenting with hypercapnic respiratory failure who exhibited paradoxic (i.e., inward) abdominal movement on inspiration during tidal breathing in the supine posture; no paradoxic abdominal motion was observed at the bedside with the patient upright. Transdiaphragmatic pressure measurements established the diagnosis of diaphragmatic paralysis, although 20 cm H2O pressure developed across the diaphragm during the latter part of a forced expiration, presumably due to the development of passive tension in the diaphragm as it was stretched near residual volume. Analysis of the relative motion of the rib cage and abdomen during breathing by the use of magnetometers confirmed the presence of abdominal paradox throughout the breathing cycle when the patient was supine, and established that paradoxic motion of the abdomen also occurred when the patient was in the erect posture but only in the latter half of inspiration. Our findings confirm that the use of transdiaphragmatic pressure measurements and magnetometry will help to quantify diaphragmatic function, that passive tension develops in the paralyzed diaphragm near residual volume and should not be confused with active contraction, and that paradoxic motion of the abdomen may be masked from the clinician when the patient is erect.

Aged↗
PubMed1977

Topical cardiac hypothermia and phrenic nerve injury.

The relationship between ice-chip cardioplegia and impaired left diaphragmatic function was evaluated in dogs. Direct or indirect contact of the phrenic nerve with crushed ice for 30 or 60 minutes resulted in phrenic paralysis for 6 to 28 days, with responsiveness returning from 7 to 62 days later. Microscopical examination of injured nerves revealed injury to the myelin sheath and preservation of axons. Paralysis of the left diaphragm after topical cardiac hypothermia may be secondary to cold injury of the phrenic nerve, which is reversible.

Animals↗