Intraoperative management of heart-lung interactions: "from hypothetical prediction to improved titration".

Extensive literature describes the suitability of dynamic parameters to predict responsiveness in fluid. However, based on heart-lung interactions, these parameters can have serious limitations, including the use of protective lung ventilation. Although the latter seems to be beneficial for healthy patients undergoing high-risk surgery, the intraoperative interpretation of dynamic parameters to predict fluid responsiveness can be hazardous. In this context, the attending physician could, alternatively, titrate the need of fluids with a small fluid challenge, which remains unaffected by low tidal volume, the presence of arrhythmia, or the presence of spontaneous ventilation. When intraoperative prediction of fluid responsiveness is required in mechanically ventilated patients, "improved" titration should be preferred to a hypothetical prediction.

Pressure-controlled ventilation and intrabronchial pressure during one-lung ventilation.

BACKGROUND: Pressure-controlled ventilation (PCV) has been suggested to reduce peak airway pressure (P(peak)) and intrapulmonary shunt during one-lung ventilation (OLV) when compared with volume-controlled ventilation (VCV). At the same tidal volume (V(T)), the apparent difference in P(peak) is mainly related to the presence of a double-lumen tracheal tube. We tested the hypothesis that the decrease in P(peak) observed in the breathing circuit is not necessarily associated with a decrease in the bronchus of the dependent lung. METHODS: This observational study included 15 consecutive subjects who were ventilated with VCV followed by PCV at constant V(T). Airway pressure was measured simultaneously in the breathing circuit and main bronchus of the dependent lung after 20 min of ventilation. RESULTS: PCV induced a significant decrease in P(peak) [mean (sd)] measured in the breathing circuit [36 (4) to 26 (3) cm H(2)0, P<0.0001] and in the bronchus [23 (4) to 22 (3) cm H(2)O, P=0.01]. However, the interaction (ventilatory mode x site of measurement) revealed that the decrease in P(peak) was significantly higher in the circuit (P<0.0001). Although the mean percentage decrease in P(peak) was significant at both sites, the decrease was significantly lower in the bronchus [5 (6)% vs 29 (3)%, P<0.0001]. CONCLUSIONS: During PCV for OLV, the decrease in P(peak) is observed mainly in the respiratory circuit and is probably not clinically relevant in the bronchus of the dependent lung. This challenges the common clinical perception that PCV offers an advantage over VCV during OLV by reducing bronchial P(peak).

[Stomach rupture associated with noninvasive ventilation]. / Rupture gastrique au décours d'une séance de ventilation non invasive.

Noninvasive positive-pressure ventilation (NIPPV) is a safe method to treat acute respiratory failure and is known to decrease the need for intubation and the length of ICU-stay. Few severe complications have been reported even when the indications are respected. Some rare cases of gastric distension were recently described. We report the case of a gastric perforation associated with NIPPV. The treatment was closure with a primary interrupted two-layer suture. Recovery was complete and the patient was transferred to the ward on Day 11.

[Effectiveness of a recruitment manoeuvre and positive end-expiratory pressure on respiratory mechanics during laparoscopic bariatric surgery]. / Efficacité d'une manoeuvre de recrutement alvéolaire associée à une pression expiratoire positive sur la mécanique respiratoire en coeliochirurgie bariatrique.

OBJECTIVE: To evaluate recruitment manoeuvre (RM) efficiency associated with a 10 cmH(2)O positive end expiratory pressure (PEEP) on respiratory mechanic estimated by lung compliance (Ctp) and PEEP to ZEEP expiratory volume delta (Delta VTE) during laparoscopic bariatric surgery in patients with morbid obesity. STUDY DESIGN: Prospective randomized study. METHODS: Twenty-six obese patients (BMI>40 kg/m(2)) undergoing laparoscopic bariatric surgery. The recruitment group received an RM followed by a 10 cmH(2)O PEP versus only 10 cmH(2)O PEP in the control group. Ctp was measured during the intervention and functional residual capacity (FRC) was estimated measuring Delta VTE during a PEP to ZEP manoeuvre. Mann and Whitney tests as well as a t-test were used (significance p<0.05). RESULTS: In the RM group, a significant improvement of 52+/-14 ml/cmH(2)O was noted versus a 36+/-10 ml/cmH(2)O in the PEP group (p=0,004). This improvement was transitory and no statistically significant Delta VTE difference was noted between the groups at the end of the intervention (360 [90-770]ml [MRA] and 310 [190-450]ml [PEP]). CONCLUSION: In patients with morbid obesity undergoing laparoscopic bariatric surgery, an RM conducted prior the pneumoperitoneum temporarily improves lung mechanics but without any change of the end expiratory lung volume at the end of the surgery in comparison with PEP alone. The RM was well tolerated.