Central sensitization plays a crucial role in the development of chronic pain. NMDA receptors play a key role in central sensitization. Ketamine, an NMDA receptor antagonist, can help in refractory chronic pain. Although intravenous is the most common route utilized for delivery of ketamine, other routes such as oral, subcutaneous, topical and intranasal, have been explored. Here we review key research articles regarding the use of ketamine for chronic pain.

Trauma is a significant health problem and a leading cause of death in all age groups. Pain related to trauma is severe, but is often undertreated in trauma population. Opioids are widely used to treat pain in trauma patients but being associated with undesirable effects. In contrast, regional analgesia confers excellent site-specific pain relief that is free from major side effects, reduces opioid requirement and is safe and easy to perform. Specific populations that have shown benefits (including decreased morbidity and mortality) with regional analgesic techniques include those with fractured ribs and femur and hip fractures and patients undergoing digital replantation. The use of regional anesthesia in patients at risk for compartment syndrome is controversial; although the data is sparse, there is no evidence that peripheral nerve blocks delay the diagnosis. The benefit of regional analgesia is most evident when it is initiated as early as possible. The performance of nerve blocks both in the emergency room and in the field has been shown to provide quality pain relief with an excellent safety profile.

Background: More than 50 million American have chronic pain and 41% of them have poor response to the treatment. One large survey on Chronic Pain “Pain in Europe” reported it as 12%–30% in the European countries and 19.3% in a study from west India. Objective: We aimed to look for bio-psycho-social biomarkers for chronic nonspecific pain. Methods: Patients of chronic non-specific pain syndrome (CNPS) defined as “patients presenting with multiple site pain or widespread body pain for more than three days per week for more than 3 months duration without any specific medical, neurological, orthopedic or rheumatologic cause”. All patients were subjected to clinical severity scale (visual analogue score), chronic pain related quality of life (QOL) score (ranges from 0 (Bed ridden stage) to 10 (normal functioning). Then patients were subjected for complete Hemogram, serum ferritin level, serum vitamin B12 level and Vitamin D level and psycho-social screening. Psycho-social assessment done by psychologists for psychometric analysis and tools for central sensitization inventory (CSI) to find out sensitization index, Pittsburg sleep quality index (PSQI) for sleep quality, Hospital anxiety and depression scale (HADS), and Somatic symptom scale – 8 (SSS – 8) to know somatization index. Results: Among 120 patients absolute deficiency of ferritin, vitamin B12 and Vitamin D was found in 51 (42.5%), 40 (33.3%) and 60 (50%) patients respectively. High sensitization index (CSI > 50) and high somatization index (SSS-8 of > 12) was found in 22 (17.5%) and 27 (23.3%) patients respectively. Patients with low ferritin had better outcome. Conclusion: This bio-psycho-social model for chronic pain will help the clinicians and patients for better understanding of the problem and better prediction for outcome.

Objective: Transcutaneous electrical nerve stimulation (TENS) is a common modality used to treat acute and chronic painful conditions. The aim of this study is to find out the effect of immediate preoperative TENS on intraoperative anesthetic drug consumption in patients undergoing lumbar discectomy under general anesthesia. Methods: Sixty patients undergoing lumbar discectomy were randomly divided into two study groups. In TENS group (Group T), TENS was applied for 1 h in the immediate preoperative period with 20 mA current, at 100 Hz frequency, in pulses of 250 μs on either side of the planned incision site. In Sham TENS group (Group S), TENS was applied for 1 h preoperatively to the patients, although with the current intensity set at “zero” mA. The pain intensity during rest as well as movement was recorded before and after TENS, by using the Visual Analog Scale (VAS) scores in both the groups. Intraoperatively, titrated doses of propofol were used to maintain a bispectral index value of 50 ± 5, and IV fentanyl was administered to maintain the heart rate and blood pressure within 20% of baseline values. Postoperatively, fentanyl 0.5 μg/kg IV was administered to achieve VAS of <4. Results: Application of TENS was found to significantly reduce the preoperative VAS score (P < 0.001). Intraoperatively, no difference in propofol and fentanyl consumption was observed in either group (P < 0.6) (P < 0.27). Recovery time and postoperative VAS scores recorded at various time intervals were comparable in both the groups. No difference in fentanyl consumption or rescue analgesia was noted in the postoperative period in both groups. Conclusions: Application of preoperative TENS provided immediate relief from pain, although without any significant decrease in the intraoperative or postoperative analgesic requirement. Furthermore, no difference was noted in the intraoperative anesthetic consumption.

Background: Annual prevalence of chronic neck pain in general population averages between 30%-50%. Among various causes of chronic neck pain cervical facet joint involvement accounts for about 54% to 67%. Interventional procedures such as medial branch nerve block, trigger point injections and dry needling have been described for management of chronic neck pain. Objectives: To determine the clinical effectiveness of cervical medial branch block and trigger point injections in the management chronic neck pain. Design: Randomized, double blinded, prospective study conducted at two different centers in India, Pain Clinic, Department of Anaesthesiology, J.N. Medical College hospital, Aligarh Muslim University, Aligarh, Delhi Pain management centre, New Delhi, India. Methods: Data analysis was done from a total of 60 patients with 30 patients in each group. Group CMB received cervical medial branch block and group TP received trigger point injection with levobupivacaine (0.25%) and triamcinolone (20mg) at two different levels. There was no sham group. Outcome Measure: Numeric rating scale (NRS), Neck Pain Disability Index (NDI), weekly analgesic requirement and subjective evaluation of patients was done at 1^st week, 3^rd week, 6^th week and 12^th week of follow up and compared with the pre-procedure value. Results: Significant pain relief was observed in both the groups of study, at 1st week of study, compared to baseline. Further follow up showed significantly better pain relief in patients receiving medial branch nerve block than patient receiving tender point injections at 3^rd, 6^th week and 12^th week. NDI score in-group CMB was significantly better as compared to group TP at 3^rd, 6^th and 12^th week follow up. Subjective evaluation of pain showed significantly greater proportion of patient with good to excellent pain relief in group receiving medial branch block. Analgesic requirement was significantly less in group CMB compared to group TP during follow up. Conclusion: Cervical medial branch block with local anaesthetic and steroid may provide long-term relief in patients with chronic neck pain than trigger point injection with no major incidence of complications in either group.

Context: Pain is a universal phenomenon. It is considered to be the “fifth vital sign.” Pain originating from intramuscular (IM) injection should not be underestimated, because a painful injection might incite severe fear of injection, which may delay the patient seeking medical help. Aims: This study was intended to determine the effectiveness of blunt pressure technique on pain response among subjects receiving IM injection. Settings and Design: Using Quantitative approach, randomized controlled trial with posttest only design was undertaken for 6 a period of 6 weeks in a tertiary care centre. Materials and Methods: Patients receiving IM injection in the injection room were selected using consecutive sampling technique. The individuals were randomly allocated to control and experimental arm using computer generated random number table in the sealed envelope. Patients with infectious skin diseases, bleeding disorder, trauma and injury, cognitive impairment were excluded from the study. Control arm received injection using standard technique and experimental arm received injection using blunt pressure technique with the operation protocol. Numerical pain rating scale was used to collect the data. Statistical Analysis Used: Descriptive statistics was used to describe the data. Mann–Whitney U-test and Kruskal–Wallis test were used to infer the data. Results: The mean pain response in the standard technique was 3.15 ± 1.44 and in the blunt pressure technique was 1.01 ± 0.98. The difference in pain response was found to be statistically significant (P < 0.001). Conclusions: Blunt pressure technique is found to be effective in reducing the pain response. Nurses can embrace this innovative technique with scientific base to alleviate the procedural pain.

Background: Regional anesthesia and analgesia are being widely used nowadays, especially for lower-segment cesarean section (LSCS). However, according to some studies, as well as our observation, there is a high incidence of pruritus among patients undergoing LSCS under regional technique as compared to nonpregnant female patients. To enhance the quality of analgesia and increase the duration of spinal anesthesia, fentanyl is often added as an adjuvant drug. Till date, only few studies have reported the incidence of pruritus among this group after spinal anesthesia with added fentanyl, but none compared it to nonpregnant patients. Aim and Objective: The primary aim of this study was to estimate the magnitude of pruritus after intrathecal fentanyl in parturient patients. The secondary objective was to establish other pathophysiological mechanisms such as patient's body habitus and sex of the baby, which might influence the incidence and severity in this population as compared to nonpregnant patients. Materials and Methods: One hundred and sixty American Society of Anesthesiologists I and II female patients aged between 18 and 45 years were divided into two equal groups. Pregnant women group underwent LSCS, while nonpregnant patients had lower limb orthopedic surgery. Spinal anesthesia was administered using 20 mcg of fentanyl with 2.5 ml of 0.5% bupivacaine. Frequency and severity of pruritus were recorded in the patients of either group. Statistical analysis of the data was done using Chi-square test and logistic regression using SPSS version 22. A P < 0.05 was considered statistically significant. Results: The incidence of pruritus among pregnant women was noted to be 21.5%, which is significantly higher (P < 0.05) than that in the nonpregnant patients (3.75%). Pregnant patient's body habitus and gender of the baby were not found to influence the incidence or severity of pruritus (P > 0.05). Conclusions: Pregnancy is not only a risk factor for pruritus after intrathecal fentanyl but is also responsible for increasing the severity of pruritus.

Objective: The objective of the study was to compare the efficacy and safety of intrathecal ropivacaine versus intrathecal bupivacaine as anesthetic agents in patients undergoing lower abdominal surgeries. Materials and Methods: In this prospective, randomized trial, patients (n = 60) were divided into two groups of 30 each. Group R (n = 30) received intrathecal ropivacaine 0.75%, 3 ml (isobaric), whereas Group B (n = 30) received intrathecal bupivacaine 0.5%, 3 ml (isobaric). The two study groups were compared with respect to onset, duration, and level of sensory block. The time for the onset of motor block, total duration of motor block, and postoperative side effects were also recorded. Statistical Analysis: Quantitative data and categorical data were analyzed using t-test and Chi-square test, respectively. P < 0.05 was considered statistically significant. Results: The maximum sensory level of T4 was reached in 6.7% and 13.3% of the cases of ropivacaine and bupivacaine (P = 0.68), respectively. The onset time (2.54 vs. 2.91 min; P > 0.05) and level (7.38 vs. 8.14 min; P > 0.05) of sensory block achieved were found to be similar to both the drugs. The duration of sensory block was comparable in both the study groups (321.72 vs. 301.45 min; P > 0.05), whereas the duration of motor block was significantly shorter with ropivacaine than bupivacaine (214.5 vs. 283.36 min; P < 0.05). Nonsignificant higher incidence of bradycardia (10% vs. 3.3%) and hypotension (13.3% vs. 3.3%) was observed with bupivacaine than ropivacaine. Conclusion: Intrathecal ropivacaine may be considered superior to intrathecal bupivacaine in terms of early motor recovery and similar duration of sensory block. Lower incidence of hypotension and bradycardia with ropivacaine, though apparently insignificant in this study, may indicate its better safety profile as compared to bupivacaine.

Transversus abdominis plane (TAP) block has been used for postoperative pain relief in various abdominal surgeries as part of the multimodal analgesic approach. In adults, the duration of action of this block is quite variable, with variable duration of effective analgesia from a single injection. In this study, we present three pediatric abdominal surgery cases, in which TAP block resulted in prolonged duration of analgesia.

In the present era of advanced medicine and patient safe practice, accidental intra-arterial injection of drugs is a rare occurrence. Compartment syndrome (CS) is one of its most detrimental complications, which leads to loss of circulation, ischemia, myonecrosis, nerve damage, and limb loss. Rapid recognition and emergent fasciotomy to relieve the compartment pressure are imperative to prevent irreversible damage. Sympathetic blockade is one of the most common interventions used in the management of early stages of CS, which interferes with the pain cycle and improves distal flow by vasodilatation. We report a complicated case of CS of the right upper limb following accidental intra-arterial injection. The patient suffered with persistent ischemic pain despite surgical decompression, which was successfully managed by continuous stellate ganglion block.

Pain is the most distressing symptom experienced by cancer patients. Postherpetic neuralgia (PHN) is a rare cause of pain in breast cancer survivors that can negatively affect their quality of life. Ultrasound-guided fascial plane blocks are among the most recent addition to anesthesiologist's armamentarium. We describe the successful use of ultrasound-guided erector spinae plane block to provide adequate pain relief in a patient with PHN refractory to pharmacological therapy.

Epidural analgesia is considered as the most effective method of labor analgesia. Intravascular catheter migration is known to occur in patients in labor. There are methods to detect an intravascular migration such as epinephrine-containing test dose and negative aspiration, but these methods are unreliable and often misleading. Therefore, a high index of suspicion is required to avert the complications of local anesthetic systemic toxicity resulting from an intravascular administration of drugs given through the epidural catheter.