Introduction: Pressure-support ventilation, is widely used in critically ill patients; however, the relative contribution of patient’s effort during assisted breathing is difficult to measure in clinical conditions. Aim of the present study was to evaluate the performance of ultrasonographic indices of diaphragm contractile activity (respiratory excursion and thickening) in comparison to traditional indices of inspiratory muscle effort during assisted mechanical ventilation. Method: Consecutive patients admitted to the ICU after major elective surgery who met criteria for a spontaneous breathing trial with pressure support ventilation were enrolled. Patients with airflow obstruction or after thoracic/gastric/esophageal surgery were excluded. Variable levels of inspiratory muscle effort were achieved by delivery of different levels of ventilatory assistance by random application of pressure support (0, 5 and 15 cmH₂O). The right hemidiaphragm was evaluated by B- and M-mode ultrasonography to record respiratory excursion and thickening. Airway, gastric and oesophageal pressures, and airflow were recorded to calculate indices of respiratory effort (diaphragm and esophageal pressure–time product). Results: 25 patients were enrolled. With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure–time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing. No correlation was found between either diaphragm or esophageal pressure–time product and diaphragm excursion (respectively, R = −0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing. Conclusions: In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

Capacity to ambulate represents an important milestone in the recovery process after total knee arthroplasty (TKA). The purpose of this study was to determine the analgesic effect of two analgesic techniques and their impact on functional walking capacity as a measure of surgical recovery. Forty ASA II–III subjects undergoing TKA were enrolled in a randomized, double-blind, single-centre study receiving 48 h postoperative analgesia with either periarticular infiltration of local anaesthetic (Group I) or continuous femoral nerve block (Group F). Breakthrough pain relief was achieved with patient-controlled analgesia (PCA) morphine. The main outcome was postoperative morphine consumption. Early (postoperative days 1–3) and late (6 weeks) functional walking capacity (2 and 6 min walk tests, 2MWT and 6MWT, respectively), degree of physical activity (CHAMPS), health-related quality of life (SF-12), and clinical indicators of knee function (WOMAC, Knee Society evaluation, and range of motion) were measured. Patients in Group F used the PCA less (P=0.02) to achieve adequate analgesia. Postoperative 2MWT was similar in both groups (P=0.27). Six weeks after surgery, recovery of 6MWT, physical activity, and knee function were significantly improved in Group F (P<0.05). Preoperative walking capacity, physical activity and early total walking time were the independent predictors of early recovery. Distance and time spent walking were the predictors of functional walking exercise capacity at 6 weeks after surgery. Femoral block is associated with lower opioid consumption and a better recovery at 6 weeks than periarticular infiltration. Early postoperative activity measures (2MWT and walking time) were proved to be possible indicators of knee function recovery at 6 weeks after surgery.

The use of opioids during ambulatory surgery can delay hospital discharge or cause unexpected hospital admission. Preliminary studies using an intraoperative continuous infusion of esmolol in place of an opioid have inconsistently reported a postoperative opioid-sparing effect. In this study, we compared esmolol versus either intermittent fentanyl or continuous remifentanil on postoperative opioid-sparing, side effects, and time of discharge. Ninety patients (consisting of three groups) were enrolled in this prospective, randomized, and observer-blinded study. The control group (n = 30) received intermittent doses of fentanyl, the esmolol group (n = 30) received a continuous infusion of esmolol (5-15 microg x kg(-1) x min(-1)) and no supplemental opioids during surgery, and the remifentanil group (n = 30) received a continuous infusion of remifentanil (0.1-0.5 mixrog x kg(-1) x min(-1)). General anesthesia was standardized, and adjuvant medications included acetaminophen, ketorolac, local anesthetics in the skin incisions, dexamethasone, and droperidol. Postoperative analgesia included fentanyl. The amount of fentanyl in the postanesthesia care unit was significantly less in the esmolol group, 91.5 +/- 42.7 microg, compared with the other two groups, remifentanil, 237.8 +/- 54.7 microg, control, 168.1 +/- 96.8 microg (P < 0.0001). The incidence of nausea was more frequent in the control (66.7%) and remifentanil (67.9%) groups compared with the esmolol group (30%) (P < 0.01). The esmolol group reached the White-Song score of 12 of 14 faster than the remifentanil group (P < 0.01), and left the hospital 45-60 min earlier (P < 0.004). Intraoperative IV infusion of esmolol contributes to a significant decrease in postoperative administration of fentanyl and ondansetron and facilitates earlier discharge.