Diaphragm is the principal muscle of respiration. Diaphragmatic dysfunction is an underestimated cause of respiratory impairment in postsurgical patients.[1] Abdominal surgeries increase the risk of postoperative diaphragmatic dysfunction.[2] This is purported due to reflex inhibition of phrenic motor output from visceral afferents.[3] Historically, monitoring for diaphragmatic excursion, diaphragmatic thickness and diaphragmatic thickening fraction has been onerous due to the need for complex equipment and expertise as fluoroscopy, transdiaphragmatic pressure measurement and computerized tomography. Point-of-care ultrasonogram (USG) is a promising modality for real-time monitoring of diaphragmatic excursion, thickness and thickening fraction. Monitoring preoperative and postoperative respiratory muscle function is at an incipient stage. Diaphragmatic movement correlates well with vital capacity and lung compliance.[7,8] Ultrasound can be used either to assess motion of the diaphragm dome or changes in diaphragm thickness as it contracts.[5] Ultrasound measures of the diaphragm dome evaluate its effectiveness in displacing the rib cage and abdomen, whereas ultrasound measures of diaphragm thickness in the zone of apposition of the diaphragm to the rib cage (ZOA) allow the clinician to directly assess diaphragm musculature. [5,6] There are no major studies in the literature which have correlated Diaphragmatic excursion, thickness and thickening fraction with preoperative pulmonary function test and functional capacity of patients undergoing major abdominal surgeries. The preoperative and postoperative changes in diaphragmatic excursion, thickness and thickening fraction and its correlation with preoperative pulmonary function and postoperative pulmonary complications have not been investigated in major abdominal surgeries. The aim of this study is to determine whether diaphragmatic excursion, diaphragmatic thickness, diaphragmatic thickening fraction performed in the preoperative period correlate with preoperative pulmonary function test and respiratory reserve of the patients and postoperative pulmonary complications (PPC). In future this study will help in assessing the diaphragmatic dysfunction and postoperative pulmonary complications. Aims and objectives: Primary aim: To correlate Diaphragmatic excursion, Diaphragmatic thickness (Max inspiration and expiration), Diaphragmatic thickening fraction with preoperative pulmonary function as measured by diaphragmatic ultrasound. Secondary aim: Whether preoperative diaphragmatic ultrasound parameters correlate with postoperative respiratory complications.
Pulmonary function test of the patients would be performed in the preoperative period on the day before surgery. Following parameters would be recorded- 1) Breath Holding Time 2) Vital capacity and Forced vital capacity 3) Functional residual capacity 4) Maximum inspiratory capacity 5) Peak expiratory flow rate After this, Diaphragmatic ultrasound would be performed and following parameters would be studied: a) Diaphragmatic excursion (left and right hemidiaphragm) b) Diaphragmatic thickness(max inspiration and expiration) c) Diaphragmatic thickening fraction(left and right hemidiaphragm) Postoperative respiratory complications if any, would be noted down like respiratory failure requiring ventilatory support in the form of Non-invasive ventilation or mechanical ventilation, no. of days on mechanical ventilation. Patients will be followed for 72 hours after surgery. This would end the study protocol. Sample size: This will be a prospective observational pilot study. We will include all the patients undergoing major abdominal surgeries over a period of one year.
Measurement of Diaphragmatic excursion: Patients would be studied in semi recumbent position between 20° and 40°. For right hemidiaphragm- With liver as an acoustic window, the probe would be placed immediately below the costal margin in the mid-clavicular line in longitudinal scanning plane with the tomographic plane angled in the cephalad direction such that the ultrasound beam lies perpendicular to the posterior third of the right hemidiaphragm. When the diaphragm is identified with 2-dimensional imaging, the M-mode interrogation line would be adjusted to be perpendicular to the movement of the posterior one-third of the right hemidiaphragm. For left hemidiaphragm- With spleen as an acoustic window, the probe would be placed immediately below the costal margin in the mid-clavicular line in longitudinal scanning plane with the tomographic plane angled in the cephalad direction such that the ultrasound beam lies perpendicular to the posterior third of the left hemidiaphragm. When the diaphragm is identified with 2-dimensional imaging, the M-mode interrogation line would be adjusted to be perpendicular to the movement of the posterior one-third of the left hemidiaphragm. The diaphragm excursion would be measured on the vertical axis of the M-mode tracing (cm) from the beginning. Diaphragmatic thickness would be measured in zone of apposition during both inspiration and expiration. High frequency linear probe would be placed in 8th or 9th intercostal space between anterior and midaxillary lines and the thickness of the muscle would be measured at a distance of 0.5-2cm from costophrenic sinus. Diaphragmatic thickening fraction – �’�ℎ�’��’��’��’��’’�’��’� �’��’� �’’�’��’’ �’��’��’��’��’��’��’��’��’��’��’� �’ �’�ℎ�’��’��’��’��’’�’��’� �’��’� �’’�’��’’ �’’�’��’��’��’��’��’��’��’��’� �’�ℎ�’��’��’��’��’’�’��’� �’��’� �’’�’��’’ �’’�’��’��’��’��’��’��’��’��’� × 100 Outcome assessment: To assess the diaphragmatic parameters (diaphragmatic excursion, diaphragmatic thickness and diaphragmatic thickening fraction) in preoperative period, and its correlation with preoperative pulmonary function test and postoperative pulmonary complications
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