Practical ventilator management

Mechanical ventilation is a common invasive intervention in intensive care units. While respiratory failure remains the most common indication for mechanical ventilation, the application and indications of this intervention are far more variable. Ventilation causes marked alteration to human physiology and is associated with complications and iatrogenic injuries. This article highlights practical aspects of patient management during invasive ventilation.     

In- and out-hospital mortality rate in surgical patients

Background: Death rates after surgery are increasingly analysed for clinical audit and quality assessment. Many studies commonly provide information only on deaths that occur during hospital stay, known as in-hospital death rates. By using hospital data set linked to death certificate registry, we recorded in- and out-hospital deaths within 30 and 60 post-operative days.

Methods: The study included all consecutive surgical procedures (denominator) under general or locoregional anaesthesia in adult patients admitted for elective or non-elective inpatient surgery. Patients undergoing planned day-case surgery or obstetrical procedures were excluded. The primary outcome was 30- and 60-day post-operative mortality rate (numerator) whether before or after discharge.

Results: The study material consisted of a sample of 36,494 surgical procedures corresponding to 28,202 patients. At 30-day, 384 (crude mortality rate of 1.1%) patients died, 314 (82%) during their hospitalisation and 70 (18%) after discharge. Factors that were associated with in-hospital mortality are ASA scores, emergency, duration of surgery and rate of admission to critical care unit. Within the 30–60 days interval, we recorded 231 supplemental deaths, 103 (45%) after discharge.

Conclusion: In-hospital mortality alone is an incomplete measure of mortality even within 30 days of care. To identify the missing deaths, hospital records need to be linked to data from death certificate. This connection with the national death registry will allow obtaining the rate of in-hospital and out-hospital death.     

Feasibility and accuracy of computer-assisted individual drill guide template for minimally invasive lumbar pedicle screw placement trajectory

ObjectiveTo discuss the feasibility and accuracy of a specific computer-assisted individual drill guide template (CIDGT) for minimally invasive lumbar pedicle screw placement trajectory (MI-LPT) through a bovine cadaveric experimental study.DesignA 3-D reconstruction model, including lumbar vertebras (L1–L5), was generated, and the optimal MI-LPTs were determined. A drill guide template with a surface made of the antitemplate of the vertebral surface, including the spinous process and the entry point vertebral surface, was created by reverse engineering and rapid prototyping techniques. Then, MI-LPTs were determined by the drill guide templates, and the trajectories made by K-wires were observed by postoperative CT scan.SettingGeneral Hospital of Shenyang Military Area Command of Chinese PLA.ResultsIn total, 150 K-wires for MI-LPTs were successfully inserted into L1-L5. The required mean time and fluoroscopy times between fixation of the template to the spinous process, entry point vertebral surface, and insertion of the K-wires for minimally invasive lumbar pedicle screw placement trajectories into each vertebra were 79.4 ± 15.0 s and 2.1 ± 0.8 times. There were no significant differences between the preoperative plan and postoperative assessment in the distance from the puncture to the midline and inclination angles according to the different levels (P > 0.05, respectively). The mean deviation between the preoperative plan and postoperative assessment in the distance from the puncture to the midline and inclination angles were 0.8 ± 0.5 mm and 0.9 ± 0.5°, respectively.ConclusionsThe potential use of the novel CIDGT, which was based on the unique morphology of the lumbar vertebra to place minimally invasive lumbar pedicle screws, is promising and could prevent too much radiation exposure intraoperatively.     

Inflammatory and degenerative phases resulting from anterior cruciate rupture in a non‐invasive murine model of post‐traumatic osteoarthritis

Joint injury is the predominant risk factor for post‐traumatic osteoarthritis development (PTOA). Several non‐invasive mouse models mimicking human PTOA investigate molecular mechanisms of disease development; none have characterized the inflammatory response to this acute traumatic injury. Our aim was to characterize the early inflammatory phase and later degenerative component in our in vivo non‐invasive murine model of PTOA induced by anterior cruciate ligament (ACL) rupture. Right knees of 12‐week‐old C57Bl6 mice were placed in flexion at a 30° offset position and subjected to a single compressive load (12N, 1.4 mm/s) to induce ACL rupture with no obvious damage to surrounding tissues. Tissue was harvested 4 h post‐injury and on days 3, 14, and 21; contralateral left knees served as controls. Histological, immunohistochemical, and gene analyzes were performed to evaluate inflammatory and degenerative changes. Immunohistochemistry revealed time‐dependent expression of mature (F4/80 positive) and inflammatory (CD11b positive) macrophage populations within the sub‐synovial infiltrate, developing osteophytes, and inflammation surrounding the ACL in response to injury. Up‐regulation of genes encoding acute pro‐inflammatory markers, inducible nitric oxide synthase, interleukin‐6 and interleukin‐17, and the matrix degrading enzymes, ADAMTS‐4 and MMP3 was detected in femoral cartilage, concomitant with extensive cartilage damage and bone remodelling over 21‐days post‐injury. Our non‐invasive model describes pathologically distinct phases of the disease, increasing our understanding of inflammatory episodes, the tissues/cells producing inflammatory mediators and the early molecular changes in the joint, thereby defining the early phenotype of PTOA. This knowledge will guide appropriate interventions to delay or arrest disease progression following joint injury. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 36:2118–2127, 2018.