Effects of extremely low-pressure pneumoperitoneum on postoperative recovery after single site robot-assisted cholecystectomy: a randomized controlled trial.

To compare immediate changes in lung compliance following the administration of two commercially available natural surfactants. We conducted a prospective, randomized study of 40 preterm infants with respiratory distress syndrome requiring surfactant. Infants received either Infasurf or Survanta. The primary outcome measure was the change in compliance assessed by bedside pulmonary monitoring. There were no significant changes in dynamic lung compliance within or between the two groups 1 hour after surfactant administration. However, infants given Survanta required more doses per patient (4 vs 2, p=0.05) and were more likely to require >2 doses (57 vs 26%, p=0.05). Infants requiring >1 dose of surfactant had a greater change in airway pressure and improved oxygenation just before the second dose when treated with Infasurf. We found no significant difference in acute changes in lung compliance. However, treatment with Infasurf seems to be more long lasting than Survanta.

STANDARD adult circle systems (with adult ventilator bellows and carbon dioxide absorber) equipped with pediatric circuit hoses, rather than semiclosed partial rebreathing systems or specially designed pediatric circle systems (with small ventilator bellows and carbon dioxide canister), often are used to ventilate infants and children during administration of anesthesia. 1–3If adult circle ventilator systems are used, it is important to understand the possible limitations and to make necessary modifications of adult techniques for use with infants. One limitation of this equipment for infant ventilation is the difficulty in determining how to set the tidal volume (TV) if using a time-cycled, volume-limited mode of ventilation to ensure that the patient receives the desired TV. The large compression volume of the circle system relative to the infant’s lung volume, 4leaks around uncuffed endotracheal tubes, effects of fresh gas flow (FGF) on delivered TV, and the mechanical difficulty of setting a small TV using an adult bellows assembly contribute to a discrepancy between set and delivered TVs.Recently, the Food and Drug Administration approved the use of a circle anesthesia system equipped with an electronic piston ventilator. This system is designed to accurately deliver small TVs by providing easy-to-use ventilator modes and controls, automatic system compliance compensation, and eliminating the interaction between FGF and TV. As a result, time-cycled, volume-limited ventilation of infants with a piston-driven ventilator may be more “user-friendly” and reliable compared with ventilation with most bellows-equipped ventilators. The purpose of our study was to compare the performance of the Drager Narkomed GS ventilator system (North American Drager, Telford, PA), equipped with a traditional ascending bellows ventilator, with the new Drager Narkomed 6000 ventilator system, which uses a circle anesthesia circuit, in ventilating an infant test lung model.A Drager Narkomed GS circle anesthesia system, equipped with a standard adult bellows and carbon dioxide absorber, and a Drager Narkomed 6000, which incorporates a Divan piston-driven ventilator (Dragerwork, AG, Lubeck, Germany), were compared regarding delivery of minute ventilation (V̇E) to an infant test lung. Both ventilator systems were equipped with a disposable pediatric circle circuit (Pediatric King; King Systems Corporation, Noblesville, IN). The test lung model used in this study has been described previously. 5–8V̇Ewas measured using a test lung (Bio-Tek Ventilator Tester; Bio-Tek Instruments, Winooski, VT). The Bio-Tek test lung includes two wire wool–filled metal canisters that simulate lungs that have either normal compliance (0.003 l/cm H2O) or low compliance (0.001 l/cm H2O), as defined by the American National Standards Institute. 9The test lung determines delivered V̇Eby measuring peak inspiratory pressure (PIP) and multiplying by the calculated lung compliance to determine the TV. V̇Eis calculated by multiplying the TV by the respiratory rate (RR). The accuracy of the test lung for V̇Eis ± 4% for TVs of 5–300 ml in the infant mode. The test lung was connected to the ventilator systems by a 3.5-mm endotracheal tube (Mallinckrodt Medical, St. Louis, MO) cut distally (removing the Murphy eye to prevent system leakage), with a 15-mm connector on each end (fig. 1). The test lung was set for ambient barometric pressure, temperature, and humidity before all testing. At the recommendation of the test lung manufacturer, the least restrictive adapter (parabolic restrictor Rp20) connected the endotracheal tube to the test lung. The study was divided into three parts (fig. 1). During all three parts of the study, an inspiratory-to-expiratory ratio of 1:2 was maintained. No significant leaks in either of the ventilator systems were detected before testing. For each condition tested, V̇Ewas measured three times. The average of these three V̇Emeasurements was used for subsequent data analysis. The V̇Edelivered by the ventilator systems to the test lung were compared during time-cycled, pressure-limited and time-cycled, volume-limited ventilation. To simulate a variety of pediatric conditions, V̇Ewas measured with both ventilator systems using a variety of RRs (20, 30, 40, and 50 breaths/min) and with the test lung set in both normal- and low-compliance infant modes. During time-cycled, pressure-limited trials the PIP was adjusted to 20, 30, 40, and 50 cm H2O. Using the GS ventilator system, the desired PIP was achieved by adjusting the drive gas flow to the bellows to medium, adjusting the bellows upward to the maximal setting, and adjusting the inspiratory pressure limit (“pop-off valve”) to the target PIP. With the 6000 ventilator system, the desired PIP was achieved by direct entry of the desired PIP value into the operation control panel. During time-cycled, volume-limited trials, TVs of 30, 40, 50, 100, 200, and 300 ml were set. With the GS ventilator system this was achieved by visual adjustment of the bellows combined with adjustment of the drive gas flow to the bellows from its initial medium setting upward or downward (if needed) until the desired TV was indicated by the machine’s spirometer. In the 6000 ventilator system, TV was adjusted by direct entry of the desired value into the operation control panel. An FGF of 3 l O2/min was used during all part A testing.Minute ventilation was measured before and after an acute decrease in test lung compliance during time-cycled, volume-limited ventilation. V̇Ewas measured starting with an RR of 20 breaths/min and a TV of 50, 100, or 200 ml, with the test lung set to mimic normal-compliance infant lungs (0.003 l/cm H2O). Then, without changing any ventilator settings, V̇Ewas measured after the test lung compliance was decreased to 0.001 l/cm H2O. An FGF of 3 l O2/min was used during all part B tests. PIP limits of 80 cm H2O for the 6000 ventilator system and maximum for the GS ventilator system were set before all testing.The test lung was set in the normal-compliance infant mode (0.003 l/cm H2O) for all testing. To test the effect of an increasing FGF, baseline V̇Emeasurements were made starting at an FGF of 1 l O2/min and a set TV of 50, 100, or 200 ml, with an RR of 20 breaths/min. Without changing ventilator settings, V̇Ewas measured after incremental increases of FGF to 3, 6, and 10 l/min. To test the effect of decreasing FGF, we reversed the procedure, obtaining baseline V̇Emeasurements starting with an FGF of 10 l O2/min, an RR of 20 breaths/min, and a set TV of 50, 100, or 200 ml. Without changing ventilator settings, the FGF was adjusted incrementally downward to 6, 3, and 1 l/min, and V̇Ewas again measured.The multiple regression technique was used to analyze the data for part A: The dependent variable was V̇E; independent variables were the ventilator systems used (GS, 6000), lung compliance, RR, and PIP (pressure-limited data) or TV (volume-limited data). For parts B and C, the repeated-measures analysis-of-variance technique was used to analyze the data. The dependent variable was V̇E; independent variables were the ventilator systems, TV, and lung compliance (part B) or FGF (part C).During time-cycled, pressure-limited ventilation both the GS and the 6000 ventilator systems generated nearly identical V̇Eover the entire range of PIPs studied in both the compliant and noncompliant infant lung models (P = 0.77 and P = 0.33, respectively;fig. 2). During time-cycled, volume-limited trials, the 6000 ventilator system could be set at all TVs; we were not able to set the GS ventilator system to achieve some higher TVs (especially at high RRs in the low-compliance lung model) or any TV less then 50 ml. Thus, no comparison data points were obtained for those TVs. Only TVs of 50, 100, and 200 ml were compared between the two ventilator systems. In the normal-compliance lung model, the 6000 ventilator system delivered slightly higher V̇Ethan the GS ventilator system, but this difference was not statistically significant (P = 0.18). In the low-compliance lung model, the 6000 ventilator system delivered greater V̇Ethan the GS ventilator system (an average increase in V̇Eof 18%;P = 0.024;fig. 3). As lung compliance was decreased from normal to low, both ventilator systems delivered less V̇E(41–58% less) to the test lung at all TVs studied during time-cycled, volume-limited ventilation (P < 0.001) (fig. 4). The 6000 ventilator system was better able to compensate for decreased lung compliance than the GS ventilator system (P < 0.001). The GS ventilator system delivered progressively more V̇Eto the test lung as FGF was increased from 1 to 10 l/min at all TVs studied (P < 0.001 for FGF, P < 0.001 forTV). The GS ventilator system delivered progressively less V̇Eto the test lung as FGF was decreased from 10 to 1 l/min at all TVs studied (P < 0.001 for FGF, P < 0.001 for TV) (fig. 5A). The 6000 ventilator system maintained nearly identical V̇Eas FGF was increased from 1 to 10 l/min at all three TVs studied (P = 0.14 for FGF, P < 0.001 for TV) or as FGF was decreased from 10 to 1 l/min at all three TVs studied (P = 0.07 for FGF, P < 0.001 for TV) (fig. 5B). We observed nearly identical performance of the GS and 6000 ventilator systems during time-cycled, pressure-limited ventilation over a wide range of RRs and PIPs and two test lung compliances. During time-cycled, volume-limited ventilation trials, at TVs that could be obtained in both systems being tested, the 6000 ventilator system delivered slightly greater V̇Ethan the GS ventilator system (an average increase of 18% as measured by the Bio-Tek test lung). This difference between systems may reflect in part how the TV was set on the GS ventilator as well as differences between the spirometers of the two systems. Smaller TVs (50 or 100 ml) were extremely difficult to set accurately with the GS ventilator system, requiring visual setting of the bellows (with 50-ml TV, the bellows was fully “seated” at the bottom of the bellows assembly) followed by adjustment of the driving gas flow to the bellows. TVs below 50 ml were not obtainable at all with the GS ventilator system (the machine’s digital spirometer display of TV does not register such low TVs). Substantial decreases in V̇Ewere observed with both ventilator systems as compliance decreased, at all TVs studied. The 6000 ventilator system was marginally better able to maintain V̇Ewith decreasing lung compliance. Changing FGF during time-cycled, volume-limited ventilation does not effect V̇Ewith the 6000 ventilator system but does influence V̇Ewith the GS system.Based on our in vitro findings, what can we conclude about possible advantages or disadvantages of a piston-driven ventilator system compared with a traditional bellows ventilator system during infant ventilation? Pediatric anesthesiologists often use the ventilator of an adult circle system in the time-cycled, pressure-limited ventilation mode during infant anesthesia because of their familiarity with this type of ventilation and the mechanical ease of setting a target PIP limit with most ventilators. Our study indicates that during time-cycled, pressure-limited ventilation, it does not make a meaningful difference if one uses either a bellows-equipped ventilator or a piston-driven ventilator; the systems deliver equivalent volumes to the infant test lung over a wide range of RRs and PIPs. The near equivalence of the V̇Eproduced by the GS and 6000 ventilator systems during time-cycled, pressure-limited ventilation reinforces observations made in prior publications using this same lung model. 5–8During time-cycled, pressure-limited ventilation, V̇Eis dependent on lung compliance, PIP achieved, and RR, regardless of the compliance of the circuit used, the precise method of achieving a given PIP with the circle system, and the ventilator system used to achieve a given PIP (Mapleson system, circle system, or free-standing ventilator). 5–8One potential disadvantage of time-cycled, pressure-limited ventilation is that if for whatever reason there were a sudden change in lung compliance or resistance in the system, such as a surgeon leaning on the chest of an infant or a kinked endotracheal tube, there would be no change in the PIP, and there would be a decrease in delivered ventilation. Other means of monitoring respirations, however, such as auscultation of breath sounds and measured expired carbon dioxide (including the configuration of the wave form), likely would diagnose such problems. In the above scenario, with time-cycled, volume-limited ventilation there would be a sudden rise in peak inflation pressure as well as changes in breath sounds and the carbon dioxide waveform, but TV might be maintained better. Our study did not assess these clinically relevant means of assessing ventilation but rather just examined the performance of each ventilator system under extreme changes in lung compliance.The GS and 6000 ventilator systems do not perform equally during time-cycled, volume-limited ventilation. The GS ventilator system cannot be used easily as a true volume-limited ventilator. Determination of an appropriate set TV based on patient weight is cumbersome. Badgwell et al. 4have described the nonlinear relationship between patient weight and set TV required for time-cycled, volume-limited ventilation in infants using adult ventilator systems (150–200 ml/kg in a 1-kg infant vs. 25 ml/kg in infants more than 10 kg). Once calculated, the smaller TVs required for infants may be mechanically difficult to set because of the lack of precision of the adult bellows assembly. The lowest TV easily set during our study trials was 200 ml, which is the first mark on the bellows assembly. Thus, those who choose to use adult circle systems for infant ventilation often adjust the volume limit of the bellows slowly upward until the desired chest expansion or target PIP is achieved. An initial PIP of approximately 20 cm H2O usually is chosen, and further adjustment of the TV upward or downward is based on chest expansion, end tidal carbon dioxide concentration, and oxygen saturation. This type of time-cycled, volume-limited ventilation might be more accurately described as time-cycled, volume-limited, pressure-guided ventilation.The 6000 ventilator system, in contrast to the GS system, is easily set for all TVs during time-cycled, volume-limited ventilation, including TVs less than 50 ml. The ability to set accurate infant TVs, along with the consistency in V̇Ewith changing FGF, would appear to be an advantage of the 6000 ventilator system for use with infants. Peters et al. 10reported successful time-cycled, volume-limited ventilation of 20 infants between 2 and 6 kg with TVs of 10 ml/kg at RRs between 25 and 40 breaths/min, using a piston-driven ventilator system. Such low TVs are not easily obtainable using the GS ventilator system. It is possible to set the GS ventilator to very low TVs by setting the bellows at the very lowest limit and then adjusting the drive gas flow to the bellows so that the desired TV is achieved; however, these low TV settings are below the technical limits of the GS spirometer and would necessitate assessment of efficacy purely on a clinical basis. Also, with any change in FGF, set TV would need to be readjusted (i.e. , if FGF were increased, set TV would need to be decreased to maintain constant V̇E; if FGF were decreased, set TV would need to be increased to maintain constant V̇E). The consistency in V̇Eover a wide range of FGFs we observed using the 6000 ventilator system is similar to results reported by Schirmer et al. 11in a test lung study using a piston-driven ventilator: TVs ranging from 20–200 ml were delivered reliably during time-cycled, volume-limited ventilation over a range of FGFs (1–6 l/min). When using the 6000 ventilator system, once an appropriate set TV has been achieved, FGF can be adjusted over a wide range without risk of inadequate ventilation (with a decrease in FGF) or overventilation or barotrauma (with an increase in FGF).Another design difference between the GS and 6000 ventilator systems as used for time-cycled, volume-limited ventilation is the response to a changing lung compliance. Our results show that the 6000 ventilator system has some ability to compensate for compliance changes; the GS ventilator system does not. Because the compensation for a decrease in lung compliance by the 6000 ventilator system is incomplete, the clinical advantage of this compliance feature needs further evaluation; a set TV may require significant upward adjustment to maintain V̇Eas lung compliance decreases, regardless of the ventilator system used. The conclusion we have reached based on our in vitro study is consistent with results reported by Schirmer et al. 11using a piston-equipped ventilator in an animal model. In that study, using newborn piglets, decreased lung compliance was induced by creation of a tension pneumothorax. Although the piston-equipped ventilator had an improved ability to maintain constant ventilation after induction of the pneumothorax, it was not able to maintain normal ventilation in several piglets. 12The actual lung compliance of the piglets may have been different from the compliance settings we studied, so that direct comparison of results is not possible. Further studies would be required to examine the clinical importance of the compensation provided by the 6000 ventilator because the acute changes in compliance that we studied may have been more extreme than those that would be observed in most clinical settings.Our study indicates that the piston-equipped Drager Narkomed 6000 ventilator system performs in a manner similar to the traditional ascending bellows-equipped Drager Narkomed GS ventilator system during time-cycled, pressure-limited ventilation. During time-cycled, volume-limited ventilation, however, the 6000 ventilator system can be set easily to achieve small TVs, but the GS ventilator system cannot. More importantly, the 6000 ventilator system allows maintenance of a constant TV during a wide range of FGFs, without further adjustment. Regardless of the ventilator system used, or the type of ventilation that is chosen (time-cycled, pressure limited vs. time-cycled, volume-limited), significant adjustment of ventilator parameters is required to maintain ventilation if lung compliance changes.It is important to emphasize that this study evaluated only the ability of each ventilator system to deliver V̇Eto a test lung; our study did not address other potential issues related to clinical use of these ventilator systems. Further studies are warranted to evaluate the clinical role of the 6000 ventilator system during infant anesthesia compared with other available systems.

The aim of this prospective study was to investigate the effect of drainage on postoperative shoulder and abdominal pain after uncomplicated laparoscopic ovarian cystectomy (LOC). Allocation to drain or not to drain was non-randomised. There were 55 patients with drainage and 56 patients without drainage. Postoperative shoulder and abdominal pain was assessed using a 10-point visual analogue scale. Postoperative hospital stay in the drainage group was longer than the non-drainage group (p = 0.040). Postoperative shoulder pain scores at 6 h and 24 h were similar between the drainage and non-drainage groups (p = 0.376 and p = 0.847, respectively). Postoperative abdominal pain was higher in the drainage group at 6 h (p = 0.009), but was similar at 24 h (p = 0.097) between the groups. These data suggest that for LOC, drainage may not be useful to prevent postoperative shoulder pain and also increases postoperative abdominal pain and length of hospital stay.

Prolonged hemorrhagic hypotension and multiple trauma not involving the lungs can, in patients, induce respiratory failure with a fall in lung compliance and a concomitant increase in the work of breathing (Moore et al. 1969). However, animals experiments have revealed conflicting results concerning the magnitude and direction of change in lung compliance after a hemorrhage. We have studied the effects of 3 hr of hypovolemic systemic hypotension (femoral a. pressure: 50 to 60 mm Hg) on lung mechanics in open chest cats ventilated by positive pressure.Mean dynamic lung compliance (CL) rose during the first 30 min post‐bleeding by 13 ± 5 per cent whereafter CL gradually fell to 26 ± 6 per cent below its initial value, in the third hr of observation. On the basis of our monitoring of vascular parameters and alveolar‐arterial PO2 differences we suggest that the early rise in CL is due to reduced pulmonary blood volume and vascular distending pressure, whereas the later fall in CL is caused by collapse and narrowing of peripheral airways. No signifiant changes in nonelastic (frictional) resistance could be detected during the 3 h observation period.

Valve replacement in haemodialysis: bleeding risk in mechanical vs bioprosthetic valves

To compare the effects of two different intraoperative CO2 pressures (8 and 15mmHg) during laparoscopic hysterectomy for benign uterine pathologies in terms of postoperative abdominal and shoulder pain, laparoscopy-mediated vegetative alterations, pain medication requirement, arterial CO2 pressure (pCO2 ), surgical parameters, and safety. Prospective randomised controlled study. German university hospital. Female patients undergoing laparoscopic hysterectomy for benign uterine pathologies. Patients were randomised to a standard pressure (SP; 15mmHg, control) or low-pressure (LP; 8mmHg, experimental) group. Primary outcomes were postoperative abdominal and shoulder pain intensities, measured via numeric rating scale (NRS) and vegetative parameters (fatigue, nausea, vomiting, bloating) at 3, 24, and 48hours postoperatively. Secondary outcomes were pain medication requirement (mg) and arterial pCO2 (mmHg). Surgical parameters and intra- and postoperative complications were also recorded. In total, 178 patients were included. Patients in the LP group (n=91) showed significantly lower postoperative abdominal and shoulder pain scores, fewer vegetative alterations, lower pain medication requirements, a shorter postoperative hospitalization, and lower intra- and postoperative arterial pCO2 values compared with the SP group (n=87; P≤0.01). No differences in intra- and postoperative complications were observed between groups. Low-pressure laparoscopy seems to be an effective and safe technique for the reduction of postoperative pain and laparoscopy-induced metabolic and vegetative alterations following laparoscopic hysterectomy for benign indications. Low-pressure laparoscopy seems to be an effective and safe technique for reduction of pain following laparoscopic hysterectomy.

The alleviation of post-surgical pain has been the subject of investigation for more than a century. In the first volume and issue of BJOG, Arnold Lea, a clinical lecturer in Obstetrics at the Hospital for Women, Manchester, UK, reported on the growing use of intrathecal cocaine for the alleviation of pain during surgery, a technique strikingly similar to the modern spinal anaesthetic, that had first been used 3 years earlier (Lea BJOG 1902;1:71–88). Similarly, the next issue contained a case report of a third repeat caesarean section with only the infiltration of local anaesthesia into the skin for anaesthesia. The author noted ‘the first part of the operation was virtually painless…[but, not surprisingly] there was a good deal of pain during the abdominal stitching, especially in sewing up the fascia’. In women with sufficient ‘nerves’ this was deemed superior to a general anaesthetic, with its risks to both mother and child (Spencer BJOG 1902;1:138–41). Prior to the development of effective surgical anaesthesia and analgesia, the good surgeon was, above everything else, fast: their actions caused pain and suffering, and patients required significant fortitude to undergo an operation. The new era allowed surgeons to ‘not hurry…not sympathise…not worry…do better work…be more careful…pause and consider [their actions]’ (Cheever What has Anaesthesia Done for Surgery? The Semi-Centennial of Anaesthesia, Massachusetts General Hospital, Boston; 1897; pp. 41–48). This facilitated a tremendous advancement in all forms of surgery, and the development of minimally invasive and modern surgical techniques (Figure 1). Minimal-access surgery is associated with less morbidity, shorter recovery times, and less postoperative pain than open surgery. Yet, pain after laparoscopic surgery remains a problem, and is associated with slower recovery and other morbidities, including chronic pelvic pain. In 1965, Steptoe published the first review of the use of laparoscopy and culdoscopy, describing the growing field and the experience gained at his institution since 1960. He outlined the history, indications, and complications, as they were known, describing pain after the procedure as a recognised complication (Steptoe BJOG 1965;72:535–43). Since then, the impact of the procedure on patients, including postoperative pain, has been extensively studied. In a recent BJOG paper, van Dijk et al. report on the results of a randomised trial of a simple intervention to reduce postoperative upper abdominal and shoulder pain (van Dijk et al. BJOG 2018; 125:1469–76). After filling the abdomen with warm saline, pulmonary insufflations were undertaken and carbon dioxide was expelled in an attempt to reduce the level of postoperative upper abdominal and shoulder pain, an incompletely understood entity. Although this intervention did not reduce the incidence of postoperative upper abdominal and shoulder pain, it provided us food for thought on the pathophysiology of post-laparoscopic pain. Improvements in anaesthesia and surgical techniques have led to significant improvements in postoperative pain and recovery; however, for those whose pain has not been effectively controlled, the experience still remains a significantly negative one. The alleviation of pain has certainly revolutionised surgery. Fortunately, we are far removed from the events of the earliest issues of this journal. Nonetheless, attempts to improve a patient's postoperative pain remains a laudable objective. None declared. The completed disclosure of interest form is available to view online as supporting information. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

To evaluate the effectiveness of active gas aspiration to reduce postoperative shoulder pain in infertile women undergoing day-case diagnostic laparoscopy. Seventy four infertile women undergoing diagnostic laparoscopy during July 2013 to February 2014 were randomized to an active gas aspiration or simple gas evacuation (control) group at the end of the surgery. Postoperative shoulder and wound pain were assessed using a visual analog scale at 6, 12 and 24 h after surgery. Consumption of rescue analgesics and adverse events were recorded. There were 37 patients in each group. The shoulder pain scores of the active gas aspiration group showed lower pain intensity than the simple gas evacuation group, with statistically significant results at at all time points. There was no significant difference in surgical wound pain. The proportion of patients who required postoperative rescue analgesics was lower in the study than in control group (43.2% vs. 67.6%, P = 0.035). There was no significant difference in adverse events until 24 h after surgery. Active gas aspiration provided a significantly superior effect on postoperative shoulder pain relief after diagnostic laparoscopy when compared to simple gas evacuation, without any adverse events.

PurposeLaparoscopic cholecystectomy (LC) is usually performed under the general anesthesia (GA). Aim of the study is to investigate the availability, safety and side effects of combined spinal/epidural anesthesia (CSEA) and comparison it with GA for LC.MethodsForty-nine patients who have a LC plan were included into the study. The patients were randomly divided into GA (n = 25) and CSEA (n = 24) groups. Intraoperative and postoperative adverse events, postoperative pain levels were compared between groups.ResultsAnesthesia procedures and surgeries for all patients were successfully completed. After the organization of pneumoperitoneum in CSEA group, 3 patients suffered from shoulder pain (12.5%) and 4 patients suffered from abdominal discomfort (16.6%). All these complaints were recovered with IV fentanyl administration. Only 1 patient developed hypotension which is recovered with fluid replacement and no need to use vasopressor treatment. Postoperative shoulder pain was significantly less observed in CSEA group (25% vs. 60%). Incidence of postoperative nausea and vomiting (PONV) was less observed in CSEA group but not statistically significant (4.2% vs. 20%). In the group of CSEA, 3 patients suffered from urinary retention (12.5%) and 2 patients suffered from spinal headache (8.3%). All postoperative pain parameters except 6th hour, were less observed in CSEA group, less VAS scores and less need to analgesic treatment in CSEA group comparing with GA group.ConclusionCSEA can be used safely for laparoscopic cholecystectomies. Less postoperative surgical field pain, shoulder pain and PONV are the advantages of CSEA compared to GA.

BackgroundShoulder pain and dysfunction are common after oncologic neck dissection for head and neck cancer (HNC), due to traction, compression, and devascularization injuries to the spinal accessory nerve (SAN). Shoulder pain and dysfunction can hinder postoperative rehabilitation and hygiene, activities of daily living (ADLs), and return to work after treatment for HNC. Due to the rising incidence of human papillomavirus (HPV)-associated oropharyngeal cancer, patients are often diagnosed in the third or fourth decade of life, leaving many potential working years lost if shoulder dysfunction occurs. Brief electrical stimulation (BES) is a novel technique that has been shown to enhance and accelerate neuronal regeneration after injury through a brain-derived neurotrophic growth factor (BDNF)-driven molecular pathway in multiple peripheral nerves in both humans and animals.Methods/DesignThis is a randomized controlled trial testing the effect of intraoperative BES on postoperative shoulder pain and dysfunction. All adult participants with a new diagnosis of HNC undergoing surgery with neck dissection, including Level IIb and postoperative radiotherapy, will be enrolled. Participants will undergo intraoperative BES after completion of neck dissection for 60 min continuously at 20 Hz, 3 to 5 V, in 100-msec pulses. Postoperatively, participants will be evaluated using the Constant-Murley Shoulder Score, a scale that assesses shoulder pain, ADLs, strength, and range of motion. Secondary outcomes measured will include nerve conduction studies (NCS) and electromyographic (EMG) studies, as well as scores on the Oxford Shoulder Score (OSS), the Neck Dissection Impairment Index (NDII), and the University of Washington Quality of Life (UW-QOL) score. Primary and secondary outcomes will be assessed at 6 weeks, 3 months, 6 months, and 12 months.DiscussionThe objective of this study is to evaluate the effect of BES on postoperative clinical and objective shoulder functional outcomes and pain after oncologic neck dissection. BES has been shown to be successful in accelerating peripheral nerve regeneration in both animal and human participants in multiple different peripheral nerves. If successful, this technique may provide an adjunctive prevention option for shoulder pain and dysfunction in HNC patients.Trial registrationNCT02268344: 17 October 2014.

To test the hypothesis that high-frequency ventilation (HFV) promotes lung stability we compared the temporal course of dynamic lung compliance changes after two inflations on HFV with those occurring on conventional mechanical ventilation (CMV) at two different lung volumes, specifically with and without 5 cmH2O positive end-expiratory pressure (PEEP). In our first set of experiments we ventilated six anesthetized paralyzed dogs first with CMV, then with HFV, then again with CMV using tidal volumes of 15 ml/kg at rates of 16-18 times/min for CMV and less than 90 ml and a rate of 15 Hz for HFV. In our second set of experiments we ventilated six dogs for 4 h, the 1st h with CMV at 0 cmH2O end-expiratory pressure, the 2nd h with CMV with 5 cmH2O PEEP, the 3rd h with HFV at the same mean pleural pressure, and the 4th h again with CMV with 5 cmH2O PEEP. We found the decreases in dynamic compliance with time following hyperinflations were similar on HFV and CMV (P greater than 0.5) at both lung volumes. With the lower lung volume the initial dynamic compliance following hyperinflation also tended to fall progressively from one hour to the next despite the inflations. However, with PEEP the initial dynamic compliance over successive hours tended to rise from one hour to the next. We found that changes in dynamic compliance were not necessarily reflected in the venous admixture or alveolar to arterial O2 partial pressure gradients. We thus conclude that lung stability in normal dogs is not improved during HFV, and blood gases cannot be used to predict compliance changes.

A relationship between tendon stress and strain and ultrasonic echo intensity has previously been defined in tendons, demonstrating a correlation between tissue stiffness and echo intensity. An analogous relationship between volume-dependent pressure changes and echo intensity changes in inflating lungs would indicate a correlation between lung compliance and echo intensity. Lung compliance is an important metric to diagnose pathologies which affect lung tissue mechanics, such as emphysema and cystic fibrosis. The goal of this study is to demonstrate a correlation between ultrasound echo intensity and lung tissue mechanics in an ex vivo model using a fluid-filled negative pressure bath design which provides a controlled environment for ultrasonic and mechanical measurements. Lungs from 4 male Sprague-Dawley rats were removed and mechanically tested via inflation and deflation in a negative pressure chamber filled with hetastarch. Specific volumes (1, 2, 3, and 4 mL) were removed from the chamber using a syringe to create negative pressure, which resulted in lung inflation. A pressure transducer recorded the pressure around the lungs. From these data, lung compliance was calculated. Ultrasound images were captured through the chamber wall to determine echo intensity (grayscale brightness in the ultrasound image), which was then related to mechanical parameters. Ultrasound images of the lung were successfully captured through the chamber wall with sufficient resolution to deduce echo intensity changes in the lung tissue. Echo intensity (0-255 scale) increased with volumetric changes (18.4 ± 5.5, 22.6 ± 5.1, 26.1 ± 7.5, and 42.9 ± 19.5 for volumetric changes of 1, 2, 3, and 4 mL) in a pattern similar to pressure (-6.8 ± 1.7, -6.8 ± 1.4, -9.4 ± 0.7, and -16.9 ± 6.8 cm H2O for 1, 2, 3, and 4 mL), reflecting changes in lung compliance. Measured rat lung tissue compliance was comparable to reported values from ex vivo lungs (0.178 ± 0.067, 0.378 ± 0.051, 0.427 ± 0.062, and 0.350 ± 0.160 mL/cm H20 for 1, 2, 3, and 4 mL), supporting proof of concept for the experimental method. Changes in echo intensity reflected changes in lung compliance in this ex vivo model, thus, supporting our hypothesis that the stiffness-related changes in echo intensity originally seen in tendon can be similarly detected in lung tissue. The presented ultrasound-based methods allowed measurement of local lung tissue compliance in a controlled environment, however, the methods could be expanded to facilitate both ex vivo and in vivo studies.

Lung compliance is generally considered to represent a blend of surface and tissue forces, and changes in compliance in vivo are commonly used to indicate changes in surface forces. There are, however, theoretical arguments that would allow contraction of airway smooth muscle to affect substantially the elasticity of the lung. In the present study we evaluated the role of conducting airway contraction on lung compliance in vivo by infusing methacholine (MCh) at a constant rate into the bronchial circulation. With a steady-state MCh infusion of 2.4 micrograms/min into the bronchial perfusate (perfusate concentration = 0.7 microM), there was an approximate doubling of lung resistance and a 50% fall in dynamic compliance. There were also significant decreases in chord compliance measured from the quasi-static pressure-volume curves and in total lung capacity and residual volume. When the same infusion rate was administered into the pulmonary artery, no changes in lung mechanics were observed. These results indicate that the conducting airways may have a major role in regulating lung elasticity. This linkage between airway contraction and lung compliance may account for the common observation that pharmacological challenges given to the lung usually result in similar changes in lung compliance and airway conductance. Our results also suggest the possibility that the lung tissue resistance, which dominates the measurement of lung resistance in many species, might in fact reflect the physical properties of conducting airways.

The Effect of Nasal Irritation on Lung Compliance in Laryngectomized Patients

Postoperative pain after low-pressure versus standard-pressure laparoscopic surgery in children. A randomized clinical trial.