Effect of ventilation on cerebral oxygenation in patients undergoing surgery in the beach chair position: a randomized controlled trial

BACKGROUND

Surgery in the beach chair position (BCP) may reduce cerebral blood flow and oxygenation, resulting in neurological injuries. The authors tested the hypothesis that a ventilation strategy designed to achieve end-tidal carbon dioxide (E'(CO₂)) values of 40-42 mm Hg would increase cerebral oxygenation (Sct(O₂)) during BCP shoulder surgery compared with a ventilation strategy designed to achieve E'(CO₂) values of 30-32 mm Hg.

METHODS

Seventy patients undergoing shoulder surgery in the BCP with general anaesthesia were enrolled in this randomized controlled trial. Mechanical ventilation was adjusted to maintain an E'(CO₂) of 30-32 mm Hg in the control group and an E'(CO₂) of 40-42 mm Hg in the study group. Cerebral oxygenation was monitored continuously in the operating theatre using near-infrared spectroscopy. Baseline haemodynamics and Sct(O₂) were obtained before induction of anaesthesia, and these values were then measured and recorded continuously from induction of anaesthesia until tracheal extubation. The number of cerebral desaturation events (CDEs) (defined as a ≥20% reduction in Sct(O₂) from baseline values) was recorded.

RESULTS

No significant differences between the groups were observed in haemodynamic variables or phenylephrine interventions during the surgical procedure. Sct(O₂) values were significantly higher in the study 40-42 group throughout the intraoperative period (P<0.01). In addition, the incidence of CDEs was lower in the study 40-42 group (8.8%) compared with the control 30-32 group (55.6%, P<0.0001).

CONCLUSIONS

Cerebral oxygenation is significantly improved during BCP surgery when ventilation is adjusted to maintain E'(CO₂) at 40-42 mm Hg compared with 30-32 mm Hg.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT01546636.

Essential gene profiles in breast, pancreatic, and ovarian cancer cells

Genomic analyses are yielding a host of new information on the multiple genetic abnormalities associated with specific types of cancer. A comprehensive description of cancer-associated genetic abnormalities can improve our ability to classify tumors into clinically relevant subgroups and, on occasion, identify mutant genes that drive the cancer phenotype ("drivers"). More often, though, the functional significance of cancer-associated mutations is difficult to discern. Genome-wide pooled short hairpin RNA (shRNA) screens enable global identification of the genes essential for cancer cell survival and proliferation, providing a "functional genomic" map of human cancer to complement genomic studies. Using a lentiviral shRNA library targeting ~16,000 genes and a newly developed, dynamic scoring approach, we identified essential gene profiles in 72 breast, pancreatic, and ovarian cancer cell lines. Integrating our results with current and future genomic data should facilitate the systematic identification of drivers, unanticipated synthetic lethal relationships, and functional vulnerabilities of these tumor types.

SIGNIFICANCE

This study presents a resource of genome-scale, pooled shRNA screens for 72 breast, pancreatic, and ovarian cancer cell lines that will serve as a functional complement to genomics data, facilitate construction of essential gene profiles, help uncover synthetic lethal relationships, and identify uncharacterized genetic vulnerabilities in these tumor types.

SIGNIFICANCE

This study presents a resource of genome-scale, pooled shRNA screens for 72 breast, pancreatic, and ovarian cancer cell lines that will serve as a functional complement to genomics data, facilitate construction of essential gene profiles, help uncover synthetic lethal relationships, and identify uncharacterized genetic vulnerabilities in these tumor types.

SCORPION, a molecular database of scorpion toxins

Increasing interest in the studies of toxins and the requirements for better structural and functional annotations have created a need for improved data management in the field of toxins. The molecular database, SCORPION, contains more than 200 entries of fully referenced scorpion toxin data including primary sequences, three-dimensional structures, structural and functional annotations of scorpion toxins along with relevant literature references. SCORPION has a set of search tools that allow users to extract data and perform specific queries. These entries have been compiled from public databases and literature, cleaned of errors and enriched with additional structural and functional information. The grouping of scorpion toxins provides a basis for extending and clarifying the existing structural and functional classifications. The bioinformatics modules in SCORPION facilitate analyses aimed at classification of scorpion toxins and identification of sequence patterns associated with specific structural or functional properties of scorpion toxins. The SCORPION database is accessible via the Internet at sdmc.krdl.org.sg:8080/scorpion.

Experience with an anesthesiologist interventional model for endoscopy in a pediatric hospital

BACKGROUND

Endoscopy is now a routine part of the work-up for many patients with gastrointestinal symptoms. Adults tolerate these procedures well, with either no sedation or a relatively light level. In contrast, children often require deep sedation or a general anesthetic to successfully perform these procedures. Therefore, pediatric endoscopies may require more time, personnel, and monitoring equipment to provide optimal conditions for the patient. The goals of this retrospective case series were to describe the anesthesia times and recovery duration of the different procedures, the types and amounts of medications commonly used, and the types and rates of complications experienced.

METHODS

Patients (2,306) who underwent endoscopy in the Arkansas Children's Hospital endoscopy suite during a 4-year period were identified. A random sample of 720 charts was reviewed retrospectively.

RESULTS

Patients ranged in age from younger than 1 year to 29 years. Patients most often had abdominal pain or multiple gastrointestinal symptoms. Sixty-eight percent of patients underwent esophagogastroduodenoscopies; 30% colonoscopy or a combination of the two. Ninety-five percent of patients received a propofol-based anesthetic. Midazolam, fentanyl, and alfentanil were frequently used as supplemental agents. Complications occurred infrequently and were airway related. All complications were easily treated, with no adverse sequelae.

CONCLUSIONS

This model of anesthesiologist-provided sedation/anesthesia for gastrointestinal endoscopy procedures has been extremely successful in the Arkansas Children's Hospital and has served to heighten awareness of many issues surrounding sedation and anesthesia outside of the operating room, while ensuring a high level of care is provided.

Bone density adjacent to press-fit acetabular components. A prospective analysis with quantitative computed tomography

BACKGROUND

The status of periprosthetic bone stock is an important concern when revision total hip arthroplasty is undertaken. Remodeling of periprosthetic femoral bone after total hip arthroplasty has been studied extensively, and the phenomenon of femoral stress-shielding has been well characterized. Finite element analysis and computer-simulated remodeling theory have predicted that retroacetabular bone-mineral density decreases after total hip arthroplasty; however, remodeling of periprosthetic pelvic bone in this setting has yet to be well defined. This study was conducted to evaluate the short-term natural history of periacetabular bone-mineral density following primary total hip arthroplasty.

METHODS

Periacetabular bone-mineral density was studied prospectively in a group of twenty-six patients who underwent primary hybrid total hip arthroplasty for the treatment of advanced osteoarthritis. Density within the central part of the ilium (directly cephalad to a press-fit acetabular component) was assessed with serial quantitative computed tomography. Baseline density was measured within the first five days following the total hip arthroplasty. Ipsilateral density measurements were repeated at an average of 1.28 years postoperatively. Density values at corresponding levels of the contralateral ilium were obtained at both time-points in all patients to serve as internal controls.

RESULTS

Bone-mineral density decreased significantly (p< or =0.001) between the two time-points on the side of the operation. The mean absolute magnitude of the interval density reduction (75 mg/cc) was greatest immediately adjacent to the implant (p<0.001), but it was also significantly reduced (by 35 mg/cc) at a distance of 10 mm cephalad to the implant (p = 0.001). Relative declines in mean density ranged from 33% to 20% of the baseline values. No focal bone resorption (osteolysis) was detected at the time of this short-term follow-up study. With the numbers available, no significant interval alteration in bone-mineral density was found on the untreated (internal control) side (p> or =0.07).

CONCLUSIONS

We suggest that the observed decline in bone-mineral density represents a remodeling response to an altered stress pattern within the pelvis that was induced by the presence of the acetabular implant. This finding corroborates the predictions of finite element analysis and computer-simulated remodeling theory. It remains to be seen whether this trend of atrophy of retroacetabular bone stock will continue with longer follow-up or will ultimately affect the long-term stability of press-fit acetabular components.

FIMM, a database of functional molecular immunology

FIMM database (http://sdmc.krdl.org.sg:8080/fimm ) contains data relevant to functional molecular immunology, focusing on cellular immunology. It contains fully referenced data on protein antigens, major histocompatibility complex (MHC) molecules, MHC-associated peptides and relevant disease associations. FIMM has a set of search tools for extraction of information and results are presented as lists or as reports.

Pain assessment and treatment in children with cognitive impairment: a survey of nurses' and physicians' beliefs

OBJECTIVE

To gather information about healthcare providers' beliefs regarding pain and its treatment in children with cognitive impairment.

DESIGN

A survey consisting of two acute pain vignettes (a child undergoing surgery and a child undergoing an outpatient medical procedure) was completed by 440 nurses and 146 physicians at Arkansas Children's Hospital. Respondents completed one of four different surveys that systematically varied the child's level of cognitive impairment (none, mild, moderate, severe) in both vignettes. Questions addressed expected pain, pain assessment methods, pharmacologic regimens, and nonpharmacologic interventions.

RESULTS

In general, provider discipline and level of cognitive impairment did not significantly influence responses about pain experience and treatment. Potent analgesia, regularly scheduled dosing, and nonpainful administration were selected most frequently. Self-report of pain, patient-controlled analgesia, and behavioral interventions requiring higher cognitive skills were selected less frequently for children with more severe cognitive impairment.

CONCLUSIONS

The presence of cognitive impairment appeared to influence provider decisions regarding the appropriateness of specific pain assessment and treatment methods requiring skills on the part of the child. Overall, healthcare provider views regarding analgesia and sedation were similar for all children, regardless of impairment. Whether these beliefs are consistent with clinical practice is yet to be documented.

Children with cognitive impairment: parent report of pain and coping

Information about pain in children with cognitive impairment is lacking. To gather pain-relevant information in this population, parents of 145 children with borderline to profound cognitive impairment were interviewed regarding their children's pain expression, experience, treatment, and coping behavior. Descriptions of pain expression and coping behavior were associated with the level of cognitive impairment. Children with mild to moderate cognitive impairment were more likely to be described as directly communicating their pain and exhibiting procedural coping strategies similar to those observed in children without cognitive impairments. More than half of the parents reported that their children experienced pain differently than did children without cognitive impairment, with the majority perceiving decreased pain sensitivity and greater pain tolerance. Finally, one third of parents felt that their children's pain was treated differently than that of other children. Half of these parents believed that health care providers had difficulties assessing and treating their children's pain. Results contribute to the developing foundation of information about pain in this special pediatric population.

Efficacy of parental application of eutectic mixture of local anesthetics for intravenous insertion

OBJECTIVE

To demonstrate that parent application of eutectic mixture of local anesthetics (EMLA) results in equal reduction of the pain of intravenous (IV) placement compared with clinician application of EMLA, and to assess potential difficulties with parental application.

STUDY DESIGN

A 2 x 2 randomized block design was used, with 41 children divided into two age groups (5-12 years vs 13-18 years) and randomized to one of two experimental groups (parent-applied EMLA vs clinician-applied EMLA).

METHODS

All children were scheduled to have outpatient gastrointestinal endoscopies with IV sedation. EMLA was placed at least 60 minutes before IV insertion either by the parent or a clinician, depending on the experimental group assignment. Outcome measures were child pain ratings and observed behavioral distress ratings. Parents and children were interviewed to determine parent and child anxiety levels in anticipation of the IV insertion, previous needle stick experience, and previous difficulty coping. Feasibility outcomes included technical difficulty with application of EMLA and appearance of the EMLA cream and occlusive covering.

RESULTS

Pain ratings and behavioral distress ratings in the low to moderate range for all groups and ws and were consistent w previous empiric reports of EMLA outcome. There were no significant differences in pain or distress ratings for either the age or the experimental groups. Parent ratings of their child's previous difficulty coping was related to the level of behavioral distress exhibited before (r =.50), during (r =.32) and after (r =.44) the IV insertion. In addition, children's anxiety ratings about IV insertion seemed to differ among groups (although not statistically significant for post hoc comparisons), with the most anxiety reported by the younger children when clinicians applied the EMLA and by older children when parents applied the EMLA.

CONCLUSION

Parent application of EMLA appears to be as effective as clinician application in reducing children's pain and distress associated with IV insertion. Permitting parents to apply the EMLA at home can allow children who are having procedures on an outpatient basis to benefit from topical anesthesia without having to arrive early to the clinic or hospital. Additionally, application by parents may result in less anticipatory anxiety for younger children.

Pain assessment in children with cognitive impairment. An exploration of self-report skills

Prior to surgery, 47 children (ages 8 to 17) with borderline to profound cognitive impairment were administered tasks to evaluate their understanding of the concepts of magnitude and ordinal position and their abilities to use a 0 to 5 numerical scale to rate pain levels in schematic faces. Of the 111 children (ages 4 to 14) without cognitive impairment, were administered the same tasks. Nurses conducting preoperative evaluations predicted whether children would understand the numerical scale. Fifty percent (n = 3) of children with borderline and 35% (n = 7) of children with mild cognitive impairment (and all children 8 years and older nonimpaired) correctly used the scale. Half of the children with cognitive impairment demonstrated skills (magnitude and ordinal position) that may allow them to use simpler pain rating methods. Nurses overestimated the abilities of cognitively impaired children (and younger children without cognitive impairment) to use the rating scale.