Preoperative Pressure Pain Threshold Is Associated With Postoperative Pain in Short-Stay Anorectal Surgery: A Prospective Observational Study.

BACKGROUND: Postoperative pain management is key for patient satisfaction. Pressure pain threshold (PPT) has been studied in some surgical cohorts but has not been studied in relationship to acute postoperative pain in short-stay patients undergoing anorectal surgery. We hypothesized that preoperative finger PPT measurements can identify respective patients with higher postoperative pain. Aiming to understand the relationship with subjective postoperative pain perception, we tested the hypotheses that preoperative PPT is associated with postoperative Visual Analog Scale (VAS) pain scores and correlates with postoperative analgesic consumption in short-stay patients undergoing anorectal surgery. METHODS: We prospectively assessed preoperative PPT in a cohort undergoing anorectal surgery, known as a moderately to severely painful procedure. Linear mixed-effects models were used to assess the relationship with postoperative VAS pain scores at 1 and 3 days as well as 4 weeks postoperatively. Logistic regression was used to study the relationship with additional postoperative analgesic consumption. RESULTS: We studied 128 patients and found that preoperative PPT is significantly associated with postoperative pain (P value for interaction = .025). Logistic regression modeling additionally revealed an association between the preoperative PPT and the need for additional postoperative analgesics, with odds of requiring additional analgesia decreasing by about 10% for each 1-point increase in PPT (odds ratio [OR] = 0.90; 95% confidence interval [CI], 00.81-0.98; P = .012). CONCLUSIONS: Preoperative finger PPT is associated with postoperative pain and might help identify patients who are at risk of developing more severe postoperative pain on anorectal surgery. Especially in ambulatory and short-stay settings, this approach can help to address patients' high variability in pain sensitivity to facilitate appropriate postoperative analgesia, timely discharge, and prevent readmission.

The influence of lifestyle (smoking and body mass index) on wound healing and long-term recurrence rate in 534 primary pilonidal sinus patients.

PURPOSE: With pilonidal sinus disease (PSD) incidence increasing, lifestyle issues have been suspected to be responsible to worsen the results of PSD surgery at the same time. The influence of smoking and body mass index (BMI) on long-term recurrence rate in primary PSD surgery has not been investigated yet. METHODS: A total of 534 patients (German military cohort) were analyzed, comparing the wound healing rates of non-smoker with smoker, as well as recurrence rates in either groups. Simultaneously, the impact of BMI on wound healing and recurrence was studied. Recurrence rate was determined by Kaplan-Meier calculation following up to 20 years after primary PSD surgery. RESULTS: Using primary open surgery, smokers' and non-smokers' recurrence rates did not differ statistically (p = 0.83; log rank). Comparable rates occurred following the primary midline closure technique (p = 0.14; log rank). A BMI of 25 and higher was not associated with adverse wound healing neither in the primary midline closure (p = 0.14) nor in the primary open treatment group (p = 0.3); nevertheless, a trend may be seen that a BMI of 25 and above could assist a favorable wound healing rate. CONCLUSIONS: The lifestyle parameter smoking and body weight statistically do not complicate wound healing or long-term recurrence rates for the first 20 years following primary PSD surgery in this study. As the BMI of 25 and above may have a beneficial influence on wound healing in primary open and primary midline closure, this observation has to be investigated for the today's surgical procedures of elective first choice-asymmetrical and flap procedures.

Incision and drainage preceding definite surgery achieves lower 20-year long-term recurrence rate in 583 primary pilonidal sinus surgery patients.

BACKGROUND: It has long been suspected that acute infection leads to less satisfactory results in soft tissue surgery. Its influence on long-term recurrence rate in primary pilonidal sinus surgery has not been investigated yet. PATIENTS AND METHODS: 583 patients (military cohort) were analyzed, comparing an incision and drainage (I&D) group preceding surgery (n = 286 pts) with a spontaneous abscess and empyema rupture group (n = 297 pts). Long-term recurrence rate up to 25 years following surgery was determined. RESULTS: The I&D group achieved a 20 year recurrence rate of 24 %, whereas the non-I&D-group had 35 % recurrences (p = 0.0034). Analyzing the subgroup with primary open wound treatment (n = 349 pts), the I&D group did significantly better after 20 years (16 % actuarial recurrence rate versus 34 %; p = 0.009; log-rank-test). CONCLUSIONS: Early I&D treatment preceding definite surgery for some weeks seem to give significant superior results compared to primary surgery without I&D. The combination of early I&D and asymmetric excision and out of the midline closure is expected to give even further improved results compared to this cohort. The optimum interval between I&D and definite surgery has still to be determined.

Reticulocyte and Erythrocyte Hemoglobin Parameters for Iron Deficiency and Anemia Diagnostics in Patient Blood Management. A Narrative Review.

Anemia, iron deficiency and other hematinic deficiencies are a major cause of perioperative transfusion needs and are associated with increased morbidity and mortality. Anemia can be caused either by decreased production of hemoglobin or red blood cells or by increased consumption and blood loss. Decreased production can involve anything from erythropoietin or vitamin B12 insufficiency to absolute or functional lack of iron. Thus, to achieve the goal of patient blood management, anemia must be addressed by addressing its causes. The traditional parameters to diagnose anemia, despite offering elaborate options, are not ideally suited to giving a simple overview of the causes of anemia, e.g., iron status for erythropoiesis, especially during the acute phase of inflammation, acute blood loss or iron deficiency. Reticulocyte hemoglobin can thus help to uncover the cause of the anemia and to identify the main factors inhibiting erythropoiesis. Regardless of the cause of anemia, reticulocyte hemoglobin can also quickly track the success of therapy and, together with the regular full blood count it is measured alongside, help in clearing the patient for surgery.

Failed Vocalis Muscle Monitoring During Thyroid Surgery Resulting From Residual Muscle Relaxation.

Postoperative paralysis of the vocal cords resulting from intraoperative surgical injury of the recurrent laryngeal nerve is one of the most serious complications of elective thyroid surgery. The chance of injury is reduced by using intraoperative neuromonitoring (IONM). This educational report describes a case of IONM failure resulting from residual muscle relaxation that was restored by administration of sugammadex. It discusses possible pharmacology explanations and provides recommendations for how to prevent this situation in daily practice.

Time-dependent inhibition of G protein-coupled receptor signaling by local anesthetics.

BACKGROUND: Several beneficial effects of local anesthetics (LAs) were shown to be due to inhibition of G protein-coupled receptor signaling. Differences in exposure time might explain discrepancies in concentrations of LAs required to achieve these protective effects in vivo and in vitro (approximately 100-fold higher). Using Xenopus oocytes and human neutrophils, the authors studied time-dependent effects of LAs on G protein-coupled receptor signaling and characterized possible mechanisms and sites of action. METHODS: Measurement of agonist-induced Ca2+-activated Cl currents, using a two-electrode voltage clamp technique, and determination of superoxide anion production by cytochrome c assay were used to assess the effects of LAs on G protein-coupled receptor signaling in oocytes and primed and activated human neutrophils, respectively. Antisense knockdown of G alpha q protein and inhibition of various proteins within the signaling pathway served for defining mechanisms and sites of action more specifically. RESULTS: LAs attenuated G protein-coupled receptor signaling in both models in a time-dependent and reversible manner (lidocaine reduced lysophosphatidic acid signaling to 19 +/- 3% after 48 h and 25 +/- 2% after 6 h of control response in oocytes and human neutrophils, respectively). Whereas no effect was observed after extracellularly applied or intracellularly injected QX314, a lidocaine analog, using G alpha q-depleted oocytes, time-dependent inhibition also occurred after intracellular injection of QX314 into undepleted oocytes. Inhibition of phosphatases or protein kinases and agonist-independent G-protein stimulation, using guanosine 5'-O-3-thiotriphosphate or aluminum fluoride, did not affect time-dependent inhibition by LAs. CONCLUSION: Inhibition of G protein-coupled receptor signaling by LAs was found to be time dependent and reversible. Critically requiring G alpha q-protein function, this effect is located downstream of guanosine diphosphate-guanosine triphosphate exchange and is not dependent on increased guanosine triphosphatase activity, phosphatases, or protein kinases.

Delayed onset of malignant hyperthermia in desflurane anesthesia.

IMPLICATIONS: Animal-experimental studies demonstrate desflurane's trigger effect for malignant hyperthermia (MH). In contrast to other anesthetics, the time interval from exposure to the occurrence of symptoms is much longer with desflurane. This case report focuses on MH induced by desflurane alone.

Bupivacaine inhibits thromboxane A2-induced vasoconstriction in rat thoracic aorta.

Plasma levels of thromboxane A2 (TXA2), an inflammatory mediator inducing platelet aggregation, bronchoconstriction, and vasoconstriction, are increased in the perioperative period. A major role in the pathogenesis of perioperative thromboembolic and ischemic syndromes is attributed to this prostanoid. Local anesthetics (LA) inhibit signaling of TXA2 receptors expressed in cell models. Therefore, we hypothesized that LA may inhibit vasoconstriction induced by the TXA2 analog U46619 in rat thoracic aorta. Rings (3-mm length) of the rat thoracic aorta were mounted in organ baths and isometric contractile force was measured. Rings, with or without endothelium, were incubated for 60 min in bupivacaine (10(-6) or 10(-5) M) or Krebs-Henseleit solution (control group) and subsequently exposed to cumulative concentrations of U46619 (10(-10) to 10(-6) M). The reversibility of the TXA2-induced vasoconstriction by bupivacaine was also studied. Pretreatment of rings with bupivacaine concentration-dependently diminished TXA2-induced contraction in rat aortic rings. We found no significant differences in relaxing effect of bupivacaine between rings with and without endothelium. Contraction in rings established with U46619 could not be reversed by cumulative concentrations of bupivacaine. Bupivacaine inhibited carbachol-induced vascular relaxation. This study provides experimental evidence that bupivacaine is an endothelium-independent inhibitor of TXA2-induced vasoconstriction of rat thoracic aorta.

Remifentanil directly activates human N-methyl-D-aspartate receptors expressed in Xenopus laevis oocytes.

BACKGROUND: Clinical studies suggest that intraoperative administration of the clinical remifentanil formulation Ultiva (GlaxoWellcome GmbH & Co, Bad Oldesloe, Germany) increases postoperative pain and postoperative analgesic requirements, but mechanisms remain unclear. N-methyl-D-aspartate (NMDA) receptors are thought to play a major role in development of postoperative pain and opiate tolerance. The authors hypothesized that Ultiva directly stimulates human NMDA receptors. METHODS: To test this hypothesis, the authors expressed human NR1A/NR2A and NR1A/NR2B NMDA receptors in Xenopus laevis oocytes by injection of messenger RNA prepared in vitro. After protein expression, they used a two-electrode voltage clamp to measure currents induced by NMDA receptor agonists and opioids. RESULTS: Noninjected cells were unresponsive to all compounds tested. Glutamate/glycine (1 nM-1 mM each) or Ultiva (0.01 pM-0.1 mM) stimulated NMDA receptors concentration dependently. NR1A/2A EC50 values were 8.0 microM/12 microM for glutamate/glycine and 3.5 nM for Ultiva, and NR1A/2B EC50 values were 3.9 microM/1.9 microM for glutamate/glycine and 0.82 microM for Ultiva. Glycine in combination with Ultiva showed no additive effect compared with Ultiva alone. Ultiva-induced currents were inhibited by MK-801 (pore blocker) but not by 7-CK (glycine antagonist), D-AP5 (glutamate antagonist), or naloxone. Fentanyl (10 microM) did not stimulate NMDA receptors. CONCLUSION: These data indicate that Ultiva but not fentanyl stimulates NMDA receptors of different subunit combinations (NR1A/2A, NR1A/2B). The mechanism seems to be allosteric activation of the NMDA receptor.