Prabhat K. Singh

Preemptive use of gabapentin significantly decreases postoperative pain and rescue analgesic requirements in laparoscopic cholecystectomy.

PurposeTo evaluate the comparative preemptive effects of gabapentin and tramadol on postoperative pain and fentanyl requirement in laparoscopic cholecystectomy.MethodsFour hundred fifty-nine ASA I and II patients were randomly assigned to receive 300 mg gabapentin, 100 mg tramadol or placebo in a double-blind manner two hours before laparoscopic cholecystectomy under general anesthesia. Postoperatively, patients’ pain scores were recorded on a visual analogue scale every two hours for the initial 12 hr and thereafter every three hours for the next 12 hr. Patients received fentanyl 2μg·kg−1 intravenously on demand. The total fentanyl consumption for each patient was recorded.ResultsPatients in the gabapentin group had significantly lower pain scores at all time intervals (2.65 ± 3.00, 1.99 ± 1.48, 1.40 ± 0.95, 0.65 ± 0.61) in comparison to tramadol (2.97 ± 2.35, 2.37 ± 1.45, 1.89 ± 1.16, 0.87 ± 0.50) and placebo (5.53 ± 2.22, 3.33 ± 1.37, 2.41 ± 1.19, 1.19 ± 0.56). Significantly less fentanyl was consumed in the gabapentin group (221.16 ± 52.39 μg) than in the tramadol (269.60 ± 44.17 μg) and placebo groups (355.86 ± 42.04 μg;P < 0.05). Sedation (33.98%), nausea/retching/vomiting (24.8%) were the commonest side effects in the gabapentin group whereas respiratory depression (3.9%) was the commonest in the tramadol group and vertigo (7.8%) in the placebo group.ConclusionPreemptive use of gabapentin significantly decreases postoperative pain and rescue analgesic requirement in laparoscopic cholecystectomy.RésuméObjectifÉvaluer et comparer les effets préventifs de la gabapentine et du tramadol sur la douleur postopératoire et les besoins de fentanyl lors d’une cholécystectomie laparoscopique.MéthodeQuatre cent cinquante-neuf patients d’état physique ASA I et II ont été répartis au hasard et ont reçu 300 mg de gabapentine, 100 mg de tramadol ou un placebo, en double aveugle, deux heures avant la cholécystectomie laparoscopique sous anesthésie générale. Après l’opération, les scores de douleur ont été notés sur l’échelle visuelle analogique toutes les deux heures pendant les 12 premières heures et toutes les trois heures pendant les 12 h suivantes. Les patients ont reçu 2 μg·kg−1 de fentanyl intraveineux sur demande et la consommation totale a été notée pour chacun.RésultatsLes patients du groupe gabapentine ont présenté des scores de douleur significativement plus bas pour tous les intervalles de mesures (2,65 ± 3,00; 1,99 ± 1,48; 1,40 ± 0,95; 0,65 ± 0,61) que ceux du groupe tramadol (2,97 ± 2,35; 2,37 ± 1,45; 1,89 ± 1,16; 0,87 ± 0,50) ou placebo (5,53 ± 2,22; 3,33 ± 1,37; 2,41 ± 1,19; 1,19 ± 0,56). La demande de fentanyl a été significativement plus basse avec la gabapentine (221,16 ± 52,39 μg) qu’avec le tramadol (269,60 ± 44,17 μg) ou le placebo (355,86 ± 42,04 μg; P < 0,05). La sédation (33,98 %), les nausées/haut-lec∁ur/vomissements (24,8 %) ont été les effets négatifs les plus fréquents avec la gabapentine tandis que la dépression respiratoire (3,9 %) a été plus fréquente avec le tramadol et le vertige (7,8 %) avec le placebo.ConclusionL’usage préventif de gabapentine diminue significativement la douleur postopératoire et la demande d’analgésique de secours lors de la cholécystectomie laparoscopique.

Evaluation of the optimal preemptive dose of gabapentin for postoperative pain relief after lumbar diskectomy: a randomized, double-blind, placebo-controlled study.

We evaluated the optimal preemptive dose of gabapentin for postoperative pain relief after single-level lumbar diskectomy and its effect on fentanyl consumption during the initial 24 hours in a randomized, double-blinded, placebo-controlled study in 100 patients with American Society of Anesthesiologists physical status I and II. Patients were divided into five groups to receive placebo or gabapentin 300, 600, 900, or 1200 mg 2 hours before surgery. After surgery, patients were transferred to the postanesthesia care unit (PACU). A blinded anesthesiologist recorded the pain scores at time points of 6, 12, 18, and 24 hours in the PACU on a Visual Analog Scale (VAS; 0-10 cm) at rest. Patients received patient-controlled analgesia (fentanyl 1.0 μg/kg on each demand with lockout interval of 10 minutes); total fentanyl consumption during initial 24 hours was recorded. Data were entered into the statistical software package SPSS 9.0 for analysis (one-way analysis of variance and Student-Newman-Keuls test). Patients who received gabapentin 300 mg had significantly lower VAS score at all time points. They consumed less fentanyl (patients who received placebo processed 1217.5 ± 182.0 versus 987.5 ± 129.6 μg; P < 0.05). Patients who received gabapentin 600, 900, and 1200 mg had lower VAS scores at all time points than patients who received gabapentin 300 mg (P < 0.05). Increasing the dose of gabapentin from 600 to 1200 mg did not decrease the VAS score, nor did the increasing dose of gabapentin significantly decrease fentanyl consumption (702.5, 635, and 626.5 μg). Thus, gabapentin 600 mg is the optimal dose for postoperative pain relief following lumbar diskectomy.

Gabapentin for the treatment of pain in guillain-barré syndrome: a double-blinded, placebo-controlled, crossover study.

Pain syndromes of Guillain-Barré are neuropathic as well as nociceptive in origin. We aimed to evaluate the therapeutic efficacy of gabapentin in relieving the bimodal nature of pain in Guillain-Barré syndrome in a randomized, double-blinded, placebo-controlled, crossover study in 18 patients admitted to the intensive care unit for ventilatory support. Patients were assigned to receive either gabapentin (15 mg · kg−1 · d−1 in 3 divided doses) or matching placebo as initial medication for 7 days. After a 2-day washout period, those who previously received gabapentin received placebo, and those previously receiving placebo received gabapentin as in the initial phase. Fentanyl 2 &mgr;g/kg was used as a rescue analgesic on patient demand or when the pain score was >5 on a numeric rating scale of 0–10. The numeric rating score, sedation score, consumption of fentanyl, and adverse effects were noted, and these observed variables were compared. The numeric pain score decreased from 7.22 ± 0.83 to 2.33 ± 1.67 on the second day after initiation of gabapentin therapy and remained low during the period of gabapentin therapy (2.06 ± 0.63) (P < 0.001). There was a significant decrease in the need for fentanyl from Day 1 to Day 7 during the gabapentin therapy period (211.11 ± 21.39 to 65.53 ± 16.17 [&mgr;g]) in comparison to the placebo therapy period (319.44 ± 25.08 to 316.67 ± 24.25 [&mgr;g]) (P < 0.001).

Preemptive gabapentin decreases postoperative pain after lumbar discoidectomy

PurposeWe investigated whether the preemptive use of gabapentin, a structural analogue of gamma amino butyric acid could reduce postoperative pain and fentanyl consumption in patients after single-level lumbar discoidectomy.MethodsFifty-six ASA I and II patients were randomly allocated into two equal groups to receive either gabapentin 300 mg or placebo two hours before surgery. After surgery, the pain was assessed on a visual analogue scale (VAS) at intervals of 0–6, 6–12, 12–18, and 18–24 hr at rest. Total fentanyl consumption in the first 24 hr after surgery was also recorded. Fentanyl 2 μg·kg−1 intravenously was used to treat postoperative pain on patients’ demand.ResultsPatients in the gabapentin group had significantly lower VAS scores at all time intervals of 0–6, 6–12, 12–18,and 18–24 hr than those in the placebo group (3.5 ± 2.3, 3.2 ± 2.1, 1.8 ± 1.7, 1.2 ± 1.3 vs 6.1 ± 1.7, 4.4 ± 1.2, 3.3 ± 1.1, 2.1 ± 1.2; P < 0.05). The total fentanyl consumed after surgery in the first 24 hr in the gabapentin group (233.5 ± 141.9, mean + SD) was significantly less than in the placebo group (359.6 ± 104.1 ; P < 0.05).ConclusionPreemptive gabapentin 300 mg po significantly decreases the severity of pain postoperatively in patients who undergo single-level lumbar discoidectomy.RésuméObjectifVérifier si l’usage préventif de gabapentine, analogue structurel de l’acide gamma amino-butyrique, pouvait réduire la douleur postopératoire et la consommation de fentanyl dans les cas de discectomie lombaire à un seul niveau.MéthodeCinquante-six patients d’état physique ASA I et II, répartis au hasard en deux groupes égaux, ont reçu soit 300 mg de gabapentine, soit un placebo, deux heures avant l’opération. Après l’opération, la douleur a été évaluée selon une échelle visuelle analogique (EVA) de 0–6, 6–12, 12–18 et 18–24 h au repos. La consommation totale de fentanyl pendant les 24 premières heures postopératoires a aussi été notée. Une dose iv de 2 μg·kg−1 de fentanyl a été utilisée pour traiter la douleur postopératoire sur demande.RésultatsLes patients sous gabapentine ont eu des scores significativement plus bas à l’EVA, pour toutes les mesures aux intervalles de 0–6, 6–12, 12–18 et 18–24 h, que ceux du groupe placebo (3,5 ± 2,3 ; 3,2 ±2,1 ; 1,8 ± 1,7 ; 1,2 ± 1,3 vs 6,1 ± 1,7 ; 4,4 ± 1,2 ; 3,3 ± 1,1 ; 2,1 ± 1,2 ; P < 0,05). La consommation postopératoire totale de fentanyl pendant les 24 premières heures a été significativement plus faible avec la gabapentine (233,5 ± 141,9, moyenne + écart type) qu’avec le placebo (359,6 ± 104,1 ; P < 0,05).ConclusionL’administration préventive de 300 mg po de gabapentine diminue significativement la sévérité de la douleur postopératoire chez les patients qui subissent une discectomie lombaire à un seul niveau.

Intravenous lidocaine suppresses fentanyl-induced coughing: a double-blind, prospective, randomized placebo-controlled study.

IV lidocaine is effective in suppressing the cough reflex of tracheal intubation, extubation, bronchography, bronchoscopy, and laryngoscopy. We investigated this effect of lidocaine on fentanyl-induced cough in 502 patients of ASA physical status I and II scheduled for elective surgery. The patients were assigned to 2 equal groups to receive either lidocaine 1.5 mg/kg or placebo (0.9% saline) over 5 s 1 min before the administration of fentanyl 3 &mgr;g/kg in a randomized and double-blind fashion. Coughs were classified as coughing and graded as mild (1–2), moderate (3–4), or severe (5 or more). The results of the study suggest that IV lidocaine 1.5 mg/kg, when administered 1 min before fentanyl, is significantly effective in suppressing fentanyl-induced cough compared to placebo (0.9% saline) (218 versus 165 patients) (P < 0.002) but without affecting the severity of cough (P > 0.05).

Gabapentin provides effective postoperative analgesia whether administered pre-emptively or post-incision

PurposeWe investigated the effects of pre-incision and postincision administration of gabapentin on postoperative pain and fentanyl consumption associated with open donor nephrectomy.MethodsSixty ASA I subjects were randomly allocated into three groups to receive gabapentin 600 mg two hours before surgery and placebo after surgical incision (pre-incision group), placebo two hours before surgery and gabapentin 600 mg after surgical incision (post-incision group), or placebo two hours before surgery and after surgical incision (placebo group). After surgery, pain was assessed using a visual analogue scale (VAS), (1-10 cm) at time points 0, 6, 12, 18, and 24 hr. Subjects received patient-controlled-analgesia (fentanyl 1.0 μg·kg-1 subject activated dose). Total fentanyl consumption in each group was recorded.ResultsSubjects of pre-incision and post-incision groups had lower VAS scores at all time points (3.1 ± 1.8, 2.9 ± 1.3, 2.8 ± 1.3, 2.5 ± 0.9, 2.5 ± 1.5 and 3.6 ± 1.1, 3.0 ± 1.2, 3.2 ± 1.1, 2.9 ± 1.0, 2.6 ± 2.2) compared to placebo group (6.6 ± 1.3, 5.0 ± 1.0, 4.4 ± 0.7, 4.2 ± 0.8, 3.9 ± 1.0). They also used less fentanyl (563.3 μg ± 252.8 and 624.0 μg ± 210.5 respectively) compared to placebo (924.7 μg ± 417.5), (P < 0.05). No difference in total fentanyl consumption and pain scores at any time points were observed between pre- and post-incision groups.ConclusionPre-incision administration of 600 mg gabapentin has no added benefit over post-incision administration in terms of pain scores and fentanyl consumption in subjects undergoing open donor nephrectomy.RésuméObjectifNous avons vérifié les effets de la gabapentine, administrée avant ou après ľincision, sur la douleur postopératoire de même que la consommation de fentanyl lors ďune néphrectomie chez un donneur vivant.MéthodeSoixante sujets ďétat physique ASA I, répartis au hasard en trois groupes, ont reçu 600 mg de gabapentine deux heures avant ľopération et un placebo après ľincision chirurgicale (groupe pré-incision), un placebo deux heures avant ľopération et 600 mg de gabapentine après ľincision (groupe post-incision) ou un placebo deux heures avant ľopération et après ľincision (groupe placebo). La douleur postopératoire a été évaluée par une échelle visuelle analogique (EVA), de 1 à 10 cm à 0, 6, 12, 18 et 24 h. Les sujets ont eu une analgésie auto-contrölée en doses de 1,0 μg·kg-1. La consommation totale de fentanyl de chaque groupe a été notée.RésultatsLes sujets des groupes pré-incision et post-incision ont présenté les scores les plus bas à ľEVA, pour toutes les mesures (3,1± 1,8; 2,9 ± 1,3; 2,8 ± 1,3; 2,5 ± 0,9; 2,5 ± 1,5 et 3,6 ± 1,1; 3,0± 1,2; 3,2 ± 1,1; 2,9 ± 1,0; 2,6 ± 2,2), comparativement au groupe placebo (6,6 ± 1,3; 5,0 ± 1,0; 4,4 ± 0,7; 4,2 ± 0,8; 3,9 ± 1,0). Ils ont aussi utilisé moins de fentanyl (563,3 μg ± 252,8 et 624,0 μg ± 210,5 respectivement) que le groupe placebo (924,7 μg ± 417.5), (P < 0,05). Aucune différence de consommation totale de fentanyl et de scores de douleur n’a été observée entre les groupes pré-incision et post-incision.ConclusionĽadministration pré-incision de 600 mg de gabapentine n’a pas ďavantage sur ľadministration post-incision quant aux scores de douleur et à la consommation de fentanyl chez des donneurs vivants qui subissent une néphrectomie.

Pretreatment with thiopental for prevention of pain associated with propofol injection.

Propofol causes pain on IV injection in 28%–90% of patients. A number of techniques have been tried to minimize propofol-induced pain, with variable results. We compared the efficacy of pretreatment with thiopental 0.25 mg/kg and 0.5 mg/kg and lidocaine 40 mg after venous occlusion for prevention of propofol-induced pain. One-hundred-twenty-four adult patients, ASA physical status I–II, undergoing elective surgery were randomly assigned into 4 groups of 31 each. Group I received normal saline, group II received lidocaine 2% (40 mg), and groups III and IV received thiopental 0.25 mg/kg and 0.5 mg/kg, respectively. All pretreatment drugs were made in 2 mL and were accompanied by manual venous occlusion for 1 min. Propofol was administered after release of venous occlusion. Pain was assessed with a four-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain at the time of propofol injection. Twenty-four patients (77%) complained of pain in the group pretreated with normal saline as compared with 12 (39%), 10 (32%), and 1 (3%) in the groups pretreated with lidocaine 40 mg, thiopental 0.25 mg/kg, and thiopental 0.5 mg/kg, respectively (P < 0.05). Thiopental 0.5 mg/kg was the most effective treatment. We therefore suggest routine pretreatment with thiopental 0.5 mg/kg along with venous occlusion for 1 min for prevention of pain associated with propofol injection.

Differential effects of ketamine and midazolam on heart rate variability

Alterations in autonomic activity caused by anaesthesia can be assessed by spectral analysis of heart rate variability (HRV). This study examined the effects of ketamine and midazolam on HRV. Thirty patients of ASA PS 1 were studied. Fifteen were given ketamine (2 mg · kg−1) and 15 received midazolam (0.3 mg · kg−1), m The RR intervals of ECG were measured before and after induction of anaesthesia for ten minutes during spontaneous respiration. Power spectral density of the data was computed using fast Fourier transform. The spectral peaks within each measurement were calculated: low frequency area (LF, 0.04–0.15 Hz), high frequency area (HF, 0.15–0.5 Hz), and total power (TP, 0.04–0.5 Hz). Normalized unit power was derived as follows: low frequency area (nuLF): LF/ TP × 100%, high frequency area (nuHF): HF/TP × 100%. Both ketamine and midazolam caused reductions in all measurements of HRV power (P < 0.05). However, ketamine increased nuLF from 64 ± 14% to 75 ± 13% (P < 0.05) and decreased nuHF from 36 ± 14% to 25 ± 13% (P < 0.05), while midazolam decreased nuLF from 66 ± 15% to 54 ± 14% (P < 0.05) and increased nuHF from 34 ± 15% to 46 ± 14% (P < 0.05). These results documented that both ketamine and midazolam reduced the total power and all frequency components of power in spite of their opposing effects on autonomic nervous activity. However, normalized unit power showed the expected sympathetic activation with ketamine and sympathetic depression with midazolam since ketamine increased nuLFand midazolam decreased nuLF.RésuméIl est possible de mesurer l’activité autonome initiée par l’anesthésie au moyen de l’analyse spectrale des fluctuations de la fréquence cardiaque (FFC). Cette étude recherche les effets de la kétamine et du midazolam sur les FFC. Trente patients ASA PS I font partie de l’étude. Quinze ont reçu de la kétamine (2 mg · kg−1) et quinze du midazolam (0,3 mg · kg−1) iv. Les intervalles RR ont été mesurés à l’ECG avant et après l’induction de l’anesthésie pendant dix minutes de respiration spontanée. La densité de la puissance spectrale des données a été calculée après transformation rapide sur une échelle de Fourier. Les pointes spectrales de chaque mesure ont été calculées: zone de basse fréquence (LF, 0.04–0,15 Hz), zone de haute fréquence (HF, 0,15–0.5 Hz) et puissance totale (TP, 0,04–0,5 Hz). L’unité de puissance normalisée a été dérivee comme suit: zone de basse fréquence (nuLF): LF/TP × 100%, zone de haute fréquence (nuHF): HF/TP × 100% La kétamine et le midazolam provoquent des réductions de toutes les mesures de puissance des FFC (P < 0,05). Cependant la kétamine a augmenté nuLF de 64 ± 14% à 75 ± 13% (P < 0,05) et a diminue nuHF de 36 ± 14% à 25 ± 13% (P < 0,05), alors que le midazolam a diminué nuLF de 66 ± 14% à 54 ± 14% (P < 0,05) et a augmenté nuHF de 34 ± 15% à 46 ± 14% (P < 0,05). Ces résultats montrent que la kétamine et le diazépam réduisent tous deux la puissance totale et toutes les composantes fréquentielles de la puissance malgré leurs effets opposés sur l’activité nerveuse autonome. Cependant, l’unité de puissance normalisée a montré, comme on s’y attendait, l’activation sympathique par la kétamine et la dépression sympathique par le midazolam étant donné que la kétamine augmentait nuLF et que le midazolam diminuait nuLF.

The efficacy of tolterodine for prevention of catheter-related bladder discomfort: a prospective, randomized, placebo-controlled, double-blind study.

Bladder discomfort secondary to an indwelling urinary catheter is distressing, particularly for patients awakening from anesthesia. We sought to discover the incidence and severity of bladder discomfort in patients who were catheterized intraoperatively and to evaluate the efficacy of tolterodine, a pure muscarinic receptor antagonist, in preventing this. Two-hundred-fifteen consecutive adult patients, ASA physical status I and II, either sex, undergoing urologic surgery requiring bladder catheterization were enrolled. Group C (control, n = 165) received placebo and group T (tolterodine, n = 50) received tolterodine 2 mg. Drugs were administered orally 1 h before surgery. After induction of anesthesia, patients were catheterized with a 16F Foley catheter and the balloon was inflated with 10 mL of normal saline. In the postanesthesia care unit, bladder discomfort was assessed on arrival (0), 1, 2 and 6 h. Severity of bladder discomfort was graded as mild, moderate, and severe. Bladder discomfort observed in group C was 55% (91 of 165). Tolterodine reduced both the incidence 36% (18 of 50) and severity of bladder discomfort (P < 0.05).

An evaluation of the efficacy of aspirin and benzydamine hydrochloride gargle for attenuating postoperative sore throat: a prospective, randomized, single-blind study.

Postoperative sore throat (POST), although a minor complication, remains a source of postoperative morbidity. We compared the efficacy of dispersible aspirin gargle to benzydamine hydrochloride (a topical nonsteroidal anti inflammatory drug) gargles for prevention of POST. We enrolled 60 consecutive female patients, 16–60 yr of age, ASA physical status I or II, undergoing elective modified radical mastectomy under general anesthesia in this prospective, randomized, placebo-controlled, single-blind study. Patients were randomly divided into 3 groups of 20 subjects each: Group 1 (C) mineral water; Group 2 (AS) tab aspirin 350 mg; and Group 3 (BH) 15 mL of benzydamine hydrochloride (0.15%). All the medications were made into 30 mL of solution. Patients were asked to gargle this mixture for 30 s, 5 min before induction of anesthesia. Grading of POST was done at 0, 2, 4, and 24 h postoperatively on a 4-point scale (0–3). Aspirin gargles reduced the incidence of POST for 4 h whereas benzydamine hydrochloride gargles reduced POST for 24 h. POST was more severe in the control group at 0 and 2 h (P < 0.05). Aspirin and benzydamine hydrochloride gargles significantly reduced the incidence and severity of POST (P < 0.05).