Estimation of the transpulmonary pressure from the central venous pressure in mechanically ventilated patients.

Transpulmonary pressure (PL) calculation requires esophageal pressure (PES) as a surrogate of pleural pressure (Ppl), but its calibration is a cumbersome technique. Central venous pressure (CVP) swings may reflect tidal variations in Ppl and could be used instead of PES, but the interpretation of CVP waveforms could be difficult due to superposition of heartbeat-induced pressure changes. Thus, we developed a digital filter able to remove the cardiac noise to obtain a filtered CVP (f-CVP). The aim of the study was to evaluate the accuracy of CVP and filtered CVP swings (ΔCVP and Δf-CVP, respectively) in estimating esophageal respiratory swings (ΔPES) and compare PL calculated with CVP, f-CVP and PES; then we tested the diagnostic accuracy of the f-CVP method to identify unsafe high PL levels, defined as PL>10 cmH2O. Twenty patients with acute respiratory failure (defined as PaO2/FiO2 ratio below 200 mmHg) treated with invasive mechanical ventilation and monitored with an esophageal balloon and central venous catheter were enrolled prospectively. For each patient a recording session at baseline was performed, repeated if a modification in ventilatory settings occurred. PES, CVP and airway pressure during an end-inspiratory and -expiratory pause were simultaneously recorded; CVP, f-CVP and PES waveforms were analyzed off-line and used to calculate transpulmonary pressure (PLCVP, PLf-CVP, PLPES, respectively). Δf-CVP correlated better than ΔCVP with ΔPES (r = 0.8, p = 0.001 vs. r = 0.08, p = 0.73), with a lower bias in Bland Altman analysis in favor of PLf-CVP (mean bias - 0.16, Limits of Agreement (LoA) -1.31, 0.98 cmH2O vs. mean bias - 0.79, LoA - 3.14, 1.55 cmH2O). Both PLf-CVP and PLCVP correlated well with PLPES (r = 0.98, p < 0.001 vs. r = 0.94, p < 0.001), again with a lower bias in Bland Altman analysis in favor of PLf-CVP (0.15, LoA - 0.95, 1.26 cmH2O vs. 0.80, LoA - 1.51, 3.12, cmH2O). PLf-CVP discriminated high PL value with an area under the receiver operating characteristic curve 0.99 (standard deviation, SD, 0.02) (AUC difference = 0.01 [-0.024; 0.05], p = 0.48). In mechanically ventilated patients with acute respiratory failure, the digital filtered CVP estimated ΔPES and PL obtained from digital filtered CVP represented a reliable value of standard PL measured with the esophageal method and could identify patients with non-protective ventilation settings.

Randomized Evidence for Reduction of Perioperative Mortality: An Updated Consensus Process.

OBJECTIVE: Of the 230 million patients undergoing major surgical procedures every year, more than 1 million will die within 30 days. Thus, any nonsurgical interventions that help reduce perioperative mortality might save thousands of lives. The authors have updated a previous consensus process to identify all the nonsurgical interventions, supported by randomized evidence, that may help reduce perioperative mortality. DESIGN AND SETTING: A web-based international consensus conference. PARTICIPANTS: The study comprised 500 clinicians from 61 countries. INTERVENTIONS: A systematic literature search was performed to identify published literature about nonsurgical interventions, supported by randomized evidence, showing a statistically significant impact on mortality. A consensus conference of experts discussed eligible papers. The interventions identified by the conference then were submitted to colleagues worldwide through a web-based survey. MEASUREMENTS AND MAIN RESULTS: The authors identified 11 interventions contributing to increased survival (perioperative hemodynamic optimization, neuraxial anesthesia, noninvasive ventilation, tranexamic acid, selective decontamination of the gastrointestinal tract, insulin for tight glycemic control, preoperative intra-aortic balloon pump, leuko-depleted red blood cells transfusion, levosimendan, volatile agents, and remote ischemic preconditioning) and 2 interventions showing increased mortality (beta-blocker therapy and aprotinin). Interventions then were voted on by participating clinicians. Percentages of agreement among clinicians in different countries differed significantly for 6 interventions, and a variable gap between evidence and clinical practice was noted. CONCLUSIONS: The authors identified 13 nonsurgical interventions that may decrease or increase perioperative mortality, with variable agreement by clinicians. Such interventions may be optimal candidates for investigation in high-quality trials and discussion in international guidelines to reduce perioperative mortality.

Randomized evidence for reduction of perioperative mortality: an updated consensus process

Objective: Out of the 230 million patients undergoing major surgical procedure every year, morethan 1 million will die within 30 days. Thus, any nonsurgical interventions that help reduce perioperative mortality might save thousands of lives. We decided to update a previous consensus process to identify all the nonsurgical interventions, supported by randomized evidence, that may help reduce perioperative mortality. Design and Setting: A web-based international consensus conference. Participants: 500 hundred clinicians from 61 countries. Interventions: A systematic literature search was performed to identify published literature aboutnonsurgical interventions, supported by randomized evidence showing a statistically significant impact on mortality. Eligible papers were discussed by a Consensus Conference of experts. The interventions identified by the conference were then submitted to colleagues worldwide through aweb-based survey...

Low-dose spinal anesthesia with hyperbaric bupivacaine with intrathecal fentanyl for operative hysteroscopy: a case series study.

STUDY OBJECTIVE: To estimate the efficacy and tolerability of low dose spinal anesthesia during operative hysteroscopy in a group of patients with high surgical risks. DESIGN: Case series study (Canadian Task Force Classification II-2). SETTING: Tertiary centers for women health care. PATIENTS: A total of 47 women affected by endometrial polyps (n = 32), myomas (n = 8), and abnormal uterine bleeding (n = 7) scheduled for inpatient operative hysteroscopy. INTERVENTIONS: Transvaginal ultrasonography; office diagnostic hysteroscopy; preoperative evaluation of American Society of Anesthesiologist (ASA) classification; inpatient operative hysteroscopy; low-dose spinal anesthesia with hyperbaric bupivacaine; compilation of a questionnaire. MAIN OUTCOME MEASURES: Practicability and patients' subjective experiences with spinal anesthesia; duration of cervical dilation and for operative hysteroscopy; infusion volume needed; incidence of surgical complications. RESULTS: Resectoscopy was performed in all patients, with the exception of 1 woman (2.1%) in which spinal anesthesia was unsuccessful. No statistically significant differences were noted among groups in terms of intra- and peri-operative findings. Sensory block induced by spinal anesthesia was suitable for surgery in all patients, and side effects occurred far less frequently than mentioned in the literature. Data reported in the questionnaire revealed that 93.5% of women would choose a spinal anesthesia again for a potential operative hysteroscopy in the future, since for 89.1% of them long lasting anesthesia is of relevance. CONCLUSIONS: Low-dose spinal anesthesia is a feasible technique in the inpatient setting for operative hysteroscopy in women with high surgical risks.