¿Anestesia halogenada o anestesia total endovenosa en neurocirugía? / Volatile or total intravenous anesthesia for neurosurgery?

Total intravenous anesthesia (TIVA) with propofol/remifentanil appears in the literatura as a good option for neurosurgical patients who have increased intracranial pressure (ICP),risk of postoperative nausea and vomiting (PONV), need for neuromonitoring, and in those with impaired brain self-regulation. On the other hand, in patients with normal neurological status, normal ICP, a technique with volatile (halogenated) agents plus an opiiid can be used. This review describes two anesthetic techniques available for use in neurosurgery, highlighting the neurophysiological changes, advantages and disadvantages of each technique. MATERIAL AND METHOD: PubMed search engine was used for bibliographic search. DISCUSSION: The search for an ideal anesthetic in neurosurgery is still a matter of debate. There are numerous investigations aimed at finding an optimal agent that ensure the coupling between cerebral flow (CBF) and metabolism, keeping self-regulation intact without increasing the CBF and intracerebral pressure (ICP). CONCLUSIONS: Both anesthetic techniques, TIVA and volatile agents (halogenated), can be used in neurosurgical procedures and should provide neuroprotection, brain relaxation and a rapid awakening.

La anestesia total endovenosa (TIVA) con propofol/remifentanilo aparece en la literatura como una buena opción para pacientes neuroquirúrgicos que tienen aumento de la presión intracraneana (PIC), riesgo de náuseas y vómitos posoperatorios (NVPO), necesidad de neuromonitoreo, y en aquellos con alteración de la autorregulación cerebral. Por otra parte, en pacientes con estado neurológico normal, PIC normal puede usarse una técnica con agentes volátiles (halogenados) más un opioide. Esta revisión describe dos técnicas anestésicas disponibles para su uso en neurocirugía, destaca los cambios neurofisiológicos, ventajas y desventajas de cada técnica. MATERIAL Y MÉTODO: Para búsqueda bibliográfica se usó buscador PubMed. DISCUSIÓN: La búsqueda de un anestésico ideal en neurocirugía sigue siendo tema de debate. Existen numerosas investigaciones destinadas a buscar un agente óptimo que asegure el acoplamiento entre flujo sanguíneo cerebral (FSC) y metabolismo, manteniendo la autorregulación intacta sin aumentar el FSC y presión intracerebral (PIC). CONCLUSIONES: Ambas técnicas anestésicas, TIVA y agentes volátiles (halogenados), pueden ser usadas en procedimientos neuroquirúrgicos y deben brindar neuroprotección, relajación cerebral y un despertar rápido.

Association of 5-HT3B Receptor Gene Polymorphisms with the Efficacy of Ondansetron for Postoperative Nausea and Vomiting

PURPOSE: Postoperative nausea and vomiting (PONV) is a common problem after general anesthesia. Although 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists have significantly reduced PONV, over 35% of patients treated with ondansetron can experience PONV. In this study, we investigated whether the Y129S and -100_-102AAG deletion polymorphisms of the 5-HT3B receptor gene affect the efficacy of ondansetron in preventing PONV. MATERIALS AND METHODS: Two hundred and forty-five adult patients who underwent laparoscopic cholecystectomy were enrolled. Ondansetron 0.1 mg/kg was intravenously administered 30 minutes before the end of surgery. Genomic DNA was prepared from blood samples using a nucleic acid isolation device. Both the Y129S variant and the -100_-102AAG deletion variant were screened for using a single base primer extension assay and a DNA direct sequencing method, respectively. The relationship between genetic polymorphisms and clinical outcomes of ondansetron treatment was investigated. RESULTS: Among the 5-HT3B AAG deletion genotypes, the incidence of PONV was higher in patients with the homomutant than with other genotypes during the first 2 hours after surgery (p=0.02). There were no significant differences in the incidence of PONV among genotypes at 2-24 hours after surgery. In the Y129S variants of the 5-HT3B receptor gene, there were no significant differences in the incidence of PONV among genotypes during the first 2 hours and at 2-24 hours after surgery. CONCLUSION: The response to ondansetron for PONV was significantly influenced by the -100_-102AAG deletion polymorphisms of the 5-HT3B gene. Thus, the -100_-102AAG deletion variants may be a pharmacogenetic predictor for responsiveness to ondansetron for PONV.

Incidence and Risk Factors of Postoperative Nausea and Vomiting in Patients with Fentanyl-Based Intravenous Patient-Controlled Analgesia and Single Antiemetic Prophylaxis

PURPOSE: We evaluated the incidence and risk factors of postoperative nausea and vomiting (PONV) in patients with fentanyl-based intravenous patient-controlled analgesia (IV-PCA) and single antiemetic prophylaxis of 5-hydroxytryptamine type 3 (5 HT3)-receptor antagonist after the general anesthesia. MATERIALS AND METHODS: In this retrospective study, incidence and risk factors for PONV were evaluated with fentanyl IV-PCA during postoperative 48 hours after various surgeries. RESULTS: Four hundred-forty patients (23%) of 1878 had showed PONV. PCA was discontinued temporarily in 268 patients (14%), mostly due to PONV (88% of 268 patients). In multivariate analysis, female, non-smoker, history of motion sickness or PONV, long duration of anesthesia (>180 min), use of desflurane and intraoperative remifentanil infusion were independent risk factors for PONV. If one, two, three, four, five, or six of these risk factors were present, the incidences of PONV were 18%, 19%, 22%, 31%, 42%, or 50%. Laparoscopic surgery and higher dose of fentanyl were not risk factors for PONV. CONCLUSION: Despite antiemetic prophylaxis with 5 HT3-receptor antagonist, 23% of patients with fentanyl-based IV-PCA after general anesthesia showed PONV. Long duration of anesthesia and use of desflurane were identified as risk factors, in addition to risk factors of Apfel's score (female, non-smoker, history of motion sickness or PONV). Also, intraoperative remifentanil infusion was risk factor independent of postoperative opioid use. As the incidence of PONV was up to 50% according to the number of risk factors, risk-adapted, multimodal or combination therapy should be applied.

Factors Affecting Unused Remaining Volume of Intravenous Patient-controlled Analgesia in Patients Following Laparoscopic Gynecologic Surgery

PURPOSE: This study was undertaken to evaluate the factors affecting the unused remaining volume of intravenous patient-controlled analgesia (IV PCA) in patients who had undergone laparoscopic gynecologic surgery. METHODS: We retrospectively collected patient records from pre-existing PCA log sheets from 98 patients. Surgical factors and IV PCA-related data including remaining volume, administration duration, early discontinuation (yes or no), and adverse reactions were recorded. Chi-square test, one-way analysis of variance, and multiple linear regression were applied for data analysis. RESULTS: The average age of the 98 patients was 40.0 +/- 8.24 years. The incidence of postoperative nausea and vomiting (PONV) and early discontinuation were not statistically significant among the different surgical groups (p = .540 and p = .338, respectively). Twenty-eight patients wanted discontinuation of IV PCA and the remaining volume was 33.6 +/- 7.8 mL (range 20-55 mL). The significant determinants of remaining volume were whether IV PCA was discontinued due to PONV and duration of surgery (p < .001). The surgical duration was inversely correlated with the remaining volume. CONCLUSION: Early discontinuation of IV PCA due to PONV is a major contributing factor to wastage of medicine. Prevention and treatment of PONV is needed to encourage patients to maintain PCA use for pain control.

Patient-controlled epidural analgesia with fentanyl and bupivacaine provides better analgesia than intravenous morphine patient-controlled analgesia for early thoracotomy pain.

BACKGROUND: Intravenous patient-controlled analgesia (IVPCA) and patient-controlled epidural analgesia (PCEA) were studied in terms of analgesic efficacy, respiratory function and side effects after thoracic surgery for 24h. PCEA using fentanyl and bupivacaine as compared to IVPCA using morphine provides better pain relief both at rest and during coughing and is associated with fewer side effects. AIMS: To compare IVPCA and PCEA in terms of analgesic efficacy, respiratory function and side effects after thoracic surgery. SETTINGS AND DESIGN: Tertiary care teaching hospital. Prospective, randomized and open study. MATERIALS AND METHODS: Thirty ASA-I or II patients undergoing thoracotomy were assigned randomly to receive either IVPCA using morphine or PCEA using fentanyl and bupivacaine combination postoperatively. No background infusion was administered in either group. Postoperative evaluation included pain intensity both at rest and during coughing, degree of sedation, arterial blood gas, forced vital capacity (FVC), peak expiratory flow rate (PEFR), presence of side effects such as nausea/vomiting and pruritus at 0, 2, 8, 12 and 24h. The primary outcome of the study was the percentage of patients with analgesia failure defined as VAS>30 despite three consecutive PCA boluses requiring rescue analgesia with intravenous fentanyl. STATISTICAL ANALYSIS: Data were analyzed using t -test, chi2 test and Mann-Whitney test. RESULTS: Significantly less number of patients required rescue analgesia in PCEA group ( P< 0.05). Pain relief was better both at rest and during coughing ( P< 0.05) in PCEA group as compared to IVPCA. Patients in the PCEA group were less sedated and had fewer incidences of side effects, i.e. nausea/vomiting and pruritus. Postoperative FVC and PEFR were reduced significantly compared to baseline only in IVPCA group ( P< 0.05). CONCLUSION: After thoracic surgery, PCEA using fentanyl and bupivacaine as compared to IVPCA using morphine provides better pain relief both at rest and during coughing and associated with fewer side effects.

Intrathecal midazolam for postoperative pain relief in caesarean section delivery.

Postoperative pain relief is a growing concern to an anaesthesiologist since no single analgesic is free from side-effects. Moreover, it becomes a challenge after caesarean section delivery to provide postoperative pain relief without much sedation, respiratory depression or problems like nausea, vomiting, so that early baby acceptance and care by mother is promoted. Antinociceptive effect of midazolam is well established by now and its safety is documented. This observation was made in a blind randomised study of 40 women of ASA I/II to evaluate postoperative pain relief using intrathecal midazolam in caesarean section delivery. Group A patients (n=20) received 1.5 ml of 5% lignocaine only and group B patients (n=20) received mixture of 1.5 ml 5% lignocaine with 2 mg midazolam (preservative free) through intrathecal route at L3.4 interspace; vital parameters were monitored intra-operatively and postoperatively and Apgar score of baby in 1st and 5th minute of deliverywas assessed. It was observed intrathecal midazolam produced highly significant (p<0.001) postoperative pain relief together with anti-emetic effect and tranquillity of patients of caesarean section delivery.