Small Doses Of Fentanyl Research Articles

Fentanyl disrupts autoregulation and leads to exacerbated vasodilation in resistance arteries independent of mu-opioid receptor activation

According to the CDC, 107,375 people in the United States died of drug overdoses and poisonings in the 12-month period ending in January 2022 with 67% involving synthetic opioids like fentanyl. Recent studies have implicated the use of prescription opioids as a risk factor for cardiovascular diseases (CVD), with reported associations including myocardial infarction, coronary artery disease and vascular deterioration. With small doses of fentanyl being particularly dangerous to those who have little to no tolerance, our primary hypothesis was that acute exposure to fentanyl will abolish myogenic activity and induce exacerbated vasodilation. While the mu-opioid receptor (MOR) serves as the primary target for exogenous opioids, it has been shown that the endogenous opioids like spinorphin can induce calcium flux in neutrophils via the N-formyl peptide receptor (FPR-1). With this premise, our second hypothesis was that the vasodilatory effects of fentanyl were in part contributed by inhibition of FPR1. To test these hypotheses, mesenteric resistance arteries were isolated from 12-13-week-old male C57BL/6J mice and vascular function evaluated. Myogenic tone was evaluated via a pressure-response curve (10-140 mmHg) after a 30-minute incubation with fentanyl 10 -6 M. Contractility was evaluated via concentration-response curves to phenylephrine (Phe) in arteries pretreated with: Fentanyl 10 -6 M (Fen), Naloxone 10 -5 M (Nal, MOR antagonist), Naloxone 10 -5 M+Fentanyl 10 -6 M (Nal+Fen), Cyclosporin H 10 -5 M (Cyclo, FPR-1 antagonist), or Cyclosporin H 10 -5 M+Fentanyl 10 -6 M (Cyclo+Fen). Arteries were incubated with antagonists 15 minutes prior to a 30-minute fentanyl incubation. Control (Cont) levels were established prior to any incubations. Pressure data were analyzed using student t test and contractility data using one way anova (p<0.05* vs Cont). Fen abolished myogenic tone in arteries when compared to Cont at 40 mmHg (Cont 7.8±2.2 vs Fen 1.5±1.5*, %, n=3). Further, Fen significantly decreased contraction when compared to Cont [Area under the curve (AUC): Cont 54±5 vs. Fen 15±3 n=4*]. However, the presence of the antagonists for FPR-1 [AUC: Fen 15±3 vs. Cyclo+Fen 12 ±2, n=4, p>0.05) or mu-opioid receptor (AUC: Fen 15±3, vs. Nal+Fen 13±2, n=4, p>0.05) did not change these responses. The presence of the antagonists alone decreased contraction. This suggests a constitutive effect of FPR-1 or mu-opioid receptor on Phe-induced contractility (AUC: Cont 54±5 vs. Nal 32±10* vs. Cyclo 17±2*). Overall, our data suggest that acute treatments of Fentanyl lead to a significant disruption of autoregulation and exacerbated vasodilation in resistance arteries independent of mu and FPR-1 receptors. Therefore, chronic exposure to this opioid may lead to dysfunction and loss of myogenic tone and, subsequently, CVD. R00GM118885, R01HL149762, R00HL151889, and NHLBI (R00HL151889) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

THORACIC SEGMENTAL SPINAL ANAESTHESIA/ GENERAL ANAESTHESIA FOR LAPROSCOPY SURGERY

Background:Laparoscopic surgeries are usually done under general anesthesia, but many patients with major medical problems sometimes cannot tolerate such anesthesia, and thoracic spinal anesthesia may be beneficial in such patients. A comparative study between two groups of patients using either general anesthesia or segmental thoracic spinal anesthesia. Aim & objectives:The aim of this study is to compare mean hospital stay, patient, and surgeon satisfaction between two groups of healthy patients operated for various laparoscopic surgeries under general and segmental thoracic spinal anesthesia. Study period&place:December 2022-January2023 ( 1 month),in Narendra Modi Medical collage& L.G hospital,Ahmedabad. Patients and methods:Thirty adult patients of ASA I or II grade undergoing various laparoscopic surgeries, randomly divided into two groups of 15 patients each. Group G received conventional general anesthesia with endotracheal intubation and mechanical ventilation through Drager Fabious GS workstation.Group S received a segmental (T 7-8 inj.) thoracic spinal anesthesia using 1 .5ml of plain levobupivacaine 0.5% (7.5 mg) in addition to 25 μg fentanyl. In group G,after pneumoperitoneum for haemodynamic changes( hypertension,tachycardia) iv fentanyl alliquotes,increase sevoflurane concentration,needed.In cases not responding to them inj.Nitroglycerin infusion was given. In group S, drugs to manage patient anxiety or hemodynamic fluctuations (bradycardia or hypotension) were given when needed. Intraoperative haemodynamic monitoring, postoperative pain, complications, recovery time by modified alderte score>8 and patient & surgeon satisfaction,mean hospital stay were compared between the two groups. Results: In the GroupS, spinal anesthetia was performed easily in all 15 patients, although two complained of paresthesia, which respondedto slight needle withdrawal the block was effective for surgery in all patients, and five experienced some discomfort, shoulder pain which was readily treated with small doses of fentanyl, but none required conversion to general anesthesia five patients required midazolam for anxiety, six patients required mephentermine and atropine for hypotension and bradycardia, and recovery was uneventful and without sequelae. In group G,3(20%) patients required infusion of Nitroglycerin for hypertension& 5(33%) patient required 2 times fentonyl alliquotes of 50 mcg iv.,3(20%) patients required increase concentration of sevoflurane ( upto 5%) Conclusion: Patients of Thoracic segmental spinal anesthesia group had shorter discharge time( time to achieve modified alderte acore>8) and better patient satisfaction. Surgeon satisfaction was higher in general anesthesia group. Segmental thoracic spinal anesthesia can be used successfully and effectively for laparoscopic surgery.

Comparison Study of Lignocaine-Bupivacaine with Normal Saline and Lignocaine-Bupivacaine Along with Fentanyl in Supraclavicular Brachial Plexus Block in Mid Arm Surgeries

Background and Objective: brachial plexus block by supraclavicular approach achieve good motor, sensory
 & sympathetic blocked in mid arm surgeries. Several adjuvants have been added to enhance effect of local
 anaesthetic agent in peripheral nerve block. We performed a prospective randomized study to compare
 lignocaine-bupivacaine with normal saline and lignocaine-bupivacaine along with fentanyl for onset, quality
 & duration of block as well as post-operative analgesia.
 Method: Randomized controlled study was carried act among 50 patients of either sex aged 20-50 asa grade
 1 & 2 undergoing mid arm surgeries. patient was randomly divided in two groups. Group 1: 20ml of 0.5%
 bupivacaine + 10ml of 2% lignocaine + 1 ml of normal saline Group 2: 20ml of 0.5% bupivacaine + 10ml
 of 2% lignocaine + 1 ml of fentanyl (50 mcg)
 Time taken for onset of sensory & motor as well as complete duration of block were noted in both groups.
 Any complication during procedure during surgery as well as post operatively were noted & treated.
 Result: Addition of fentanyl (50 mcg) to bupivacaine + lignocaine in peripheral nerve block cause early
 onset for sensory block.
 Mean duration of sensory blockade 440+/-62 in group 1 while 635+/-84 in group 2. mean duration of
 analgesia 400+/-68 in group1 while 685+/-90 in group 2
 It suggests that duration of sensory block and analgesia was prolonged in group 2
 Conclusion: The addition of small-dose fentanyl to lignocaine solution in brachial plexus block can increase
 the success rate and prolong the duration of analgesia, [16]with early onset time of sensory blockade as
 compared with that achieved by the same doses of local anaesthetics used in combination.

Anesthetic management of a patient with congenital insensitivity to pain with anhidrosis by coadministration of remifentanil

BackgroundCongenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disease characterized by unexplained fever, systemic insensitivity to pain, anhidrosis, and mental distress. Anesthetic management is challenging because autonomic dysfunction can induce perioperative complications. Only a few reports of anesthetic management of CIPA patients have been published. We herein present a case of successful management of the same patient on two occasions using small doses of fentanyl and remifentanil.Case presentationA 37-year-old man with CIPA underwent two orthopedic operations. We were able to balance the dose of remifentanil to avoid the extremes of hyperalgesia when the dose is too low and shivering when the dose is too high.ConclusionTo our knowledge, no reports have described the anesthetic management of CIPA patients with remifentanil. We consider anesthetic management with coadministration of remifentanil to be potentially useful for such patients.

Awake fiberoptic nasotracheal intubation for patients with difficult airway

Awake fiberoptic nasotracheal intubation is a useful technique, especially in patients with airway obstruction. It must not only provide sufficient anesthesia, but also maintain spontaneous breathing. We introduce a method to achieve this using a small dose of fentanyl and midazolam in combination with topical anesthesia. The cases of 2 patients (1 male, 1 female) who underwent oral maxillofacial surgery are reported. They received 50 µg of fentanyl 2–3 times (total 2.2–2.3 µg/kg) at intervals of approximately 2 min. Oxygen was administered via a mask at 6 L/min, and 0.5 mg of midazolam was administered 1–4 times (total 0.02–0.05 mg/kg) at intervals of approximately 2 min. A tracheal tube was inserted through the nasal cavity after topical anesthesia was applied to the epiglottis, vocal cords, and into the trachea through the fiberscope channel. All patients were successfully intubated. This is a useful and safe method for awake fiberoptic nasotracheal intubation.

Does small-dose fentanyl improve perioperative outcomes in the ambulatory setting? A randomized, double-blind, placebo-controlled study.

Despite its widespread use, the beneficial effect of low-dose fentanyl administered at induction of anesthesia on perioperative outcomes has not been studied in the ambulatory setting. Therefore, this study was designed to test the hypothesis that administration of small-dose fentanyl vs. saline during induction reduces coughing and movements without adversely affecting recovery after day-surgery. One hundred consenting outpatients scheduled to undergo superficial surgical procedures under general anesthesia with a laryngeal mask airway (LMA) device for airway management were randomly assigned to one of two treatment groups: control (n = 50) or fentanyl (n = 50). After administration of 2 ml of the unlabelled study medication containing either fentanyl (100 μg) or saline, anesthesia was induced with lidocaine 30-50 mg and propofol 2 mg/kg IV followed by the insertion of an LMA device. General anesthesia was maintained using a propofol infusion, 75 μg/kg/min, and desflurane (2-5% end-tidal) in 100% oxygen. Coughing was observed in six (12%) and ten (20%) in the fentanyl and control group, respectively (P = 0.41). The incidence of movements during surgery was lower in the fentanyl group (18% vs. 31%, P < 0001). There were no significant differences in early and late recovery times or pain scores between the two groups. Administration of a small-dose of fentanyl at induction of anesthesia significantly reduced purposeful movements during day-surgery under propofol-desflurane anesthesia. No significant difference was found in coughing or recovery times.

Preemptive use of Small Dose Fentanyl Suppresses Fentanyl Induced Cough

Fentanyl, a synthetic opioid, is a popular choice amongst anaesthesiologists in the operating room. Pre induction intravenous fentanyl bolus is associated with coughing in 28-65% of patients. Fentanyl induced cough is not always benign and can be remarkably troublesome at the most critical moment of anaesthesia when airway reflex is lost. To study the effect of pre emptive use of minimal dose fentanyl through the peripheral venous cannulae on the incidence of cough by a larger bolus of intravenous fentanyl. One hundred and fifty patients aged 18-75 years undergoing elective surgical procedures were randomized into three groups of 50 each. The first group received 0.5 ml saline 0.9% intravenously one minute prior to the administration of fentanyl 150 μg (3 ml); the second group received pre emptive fentanyl 25 μg (0.5 ml) prior to the administration of fentanyl 125 μg (2.5 ml); and the third group received preemptive fentanyl 25 μg (0.5 ml), followed by the administration of fentanyl 150 μg (3 ml). Based on the number of coughs observed, cough severity was graded as mild (1-2), moderate (3-5), or severe (>5). The incidence of fentanyl induced cough was significantly lower in both pre emptive group 4 (8%) for 125 μg fentanyl and 7 (14%) for 150 μg than in the saline group 15 (30%). Pre-emptive use of minimal dose fentanyl 25 μg administered one minute before a larger bolus dose of fentanyl (125 or 150 μg) can effectively suppress cough.

Anesthesia for patients with liver disease.

Context:Liver plays an important role in metabolism and physiological homeostasis in the body. This organ is unique in its structure and physiology. So it is necessary for an anesthesiologist to be familiar with various hepatic pathophysiologic conditions and consequences of liver dysfunction.Evidence Acquisition:We searched MEDLINE (Pub Med, OVID, MD Consult), SCOPUS and the Cochrane database for the following keywords: liver disease, anesthesia and liver disease, regional anesthesia in liver disease, epidural anesthesia in liver disease and spinal anesthesia in liver disease, for the period of 1966 to 2013.Results:Although different anesthetic regimens are available in modern anesthesia world, but anesthetizing the patients with liver disease is still really tough. Spinal or epidural anesthetic effects on hepatic blood flow and function is not clearly investigated, considering both the anesthetic drug-induced changes and outcomes. Regional anesthesia might be used in patients with advanced liver disease. In these cases lower drug dosages are used, considering the fact that locally administered drugs have less systemic effects. In case of general anesthesia it seems that using inhalation agents (Isoflurane, Desflurane or Sevoflurane), alone or in combination with small doses of fentanyl can be considered as a reasonable regimen. When administering drugs, anesthetist must realize and consider the substantially changed pharmacokinetics of some other anesthetic drugs.Conclusions:Despite the fact that anesthesia in chronic liver disease is a scary and pretty challenging condition for every anesthesiologist, this hazard could be diminished by meticulous attention on optimizing the patient’s condition preoperatively and choosing appropriate anesthetic regimen and drugs in this setting. Although there are paucity of statistics and investigations in this specific group of patients but these little data show that with careful monitoring and considering the above mentioned rules a safe anesthesia could be achievable in these patients.

Effects of low-dose fentanyl combined with propofol in painless gastroscopy

Objective To investigate the efficacy and clinical values of low-dose fentanyl combined with propofol in painless gastroscopy.Methods 122 patients undergoing painless gastroscopy were randomly divided into study group (65 patients) and control group (57 patients).The study group received anesthesia with low-dose fentanyl plus propofol,while the control group received anesthesia with propofol alone.The anesthetic effects and adverse reactions were observed in both groups.Results Time to sleepiness and time to awakening were significantly shorter in the study group than in the control group (P＜ 0.05).The scores on the DSST was significantly greater in the study group than in the control group (P＜ 0.05).The incidence rates of respiratory depression and local pain due to injection were significantly lower in the study group than in the control group (P ＜ 0.05).Conclusions Small-dose fentanyl combined with propofol is safe and effective in painless gastroscopy. Key words: Gastroscopy; Fentanyl; Propofol

Revival of old local anesthetics for spinal anesthesia in ambulatory surgery

In recent years, several older (first intrathecal use in the 1950s, 1960s, and 1970s) local anesthetics have been investigated as spinal anesthetics in ambulatory surgery because these drugs are claimed to cause less transient neurologic symptoms (TNS) than lidocaine which was the main spinal anesthetic for surgery of short-duration for decades. The review covers the current literature. Several recent reports have dealt with the short-acting chloroprocaine and articaine and the intermediate-duration-acting prilocaine. Mepivacaine, another intermediate-acting drug, was applied in one trial only. Various dosages of these drugs either alone or with a small dose of fentanyl were compared with each other, with lidocaine, or with the currently most commonly used low-dose bupivacaine technique. The recovery from both motor and sensory block was usually reasonably fast. However, occasionally recovery after mepivacaine and prilocaine was prolonged which fits ill in a fast-flow ambulatory setting. TNS cases were very rarely reported. The newest results corroborate (at least for chloroprocaine, articaine, and prilocaine) previous data that these drugs provide reliable and mostly well tolerated spinal blocks associated with an apparently smaller risk for postanesthesic TNS as compared with lidocaine. Further studies are warranted regarding broader indications, possible usefulness of adjuvants, and for the exploration of the side-effect profiles in detail. To what extent the observed revival of these older, rather well characterized local anesthetics leads to a wider use of spinal anesthesia in the ambulatory setting remains to be seen. This is also dependent on various organizational and local traditional factors.

Effect of ketamine versus thiopental sodium anesthetic induction and a small dose of fentanyl on emergence agitation after sevoflurane anesthesia in children undergoing brief ophthalmic surgery

BackgroundEmergence agitation (EA) in children after sevoflurane anesthesia is common. The purpose of this study was to compare the incidences of EA between ketamine and thiopental sodium induction in children underwent sevoflurane anesthesia. We also evaluated if a small dose of fentanyl could reduce the incidence of EA.MethodsThe patients who were scheduled for strabismus or entropion surgery were divided into 4 groups. The patients in Groups 1 and 2 were induced anesthesia with ketamine 1.5 mg/kg; those in Groups 3 and 4 were induced with thiopental sodium 5 mg/kg. The patients in Groups 1 and 3 received an injection of fentanyl 1.5 µg/kg, whereas the patients in Groups 2 and 4 received IV saline of the same volume. Anesthesia was maintained with sevoflurane. The recovery characteristics and EA in recovery room were assessed.ResultsThe incidence of EA was significantly higher in Groups 2 and 4 and there was no difference between Groups 2 and 4. Group 2 had almost an eleven-fold higher risk of developing EA than did Group 1, and the incidence of EA in Group 4 was sixty-nine-fold higher than that of Group 1. The risk factor for EA was only the kind of medication. Preoperative anxiety had no significant correlation with EA.ConclusionsThe incidence of EA after sevoflurane anesthesia is similar between ketamine and thiopental sodium anesthetic induction in children undergoing pediatric ophthalmic surgery. Also, the addition of a small dose of fentanyl after anesthetic induction decreases the incidence of EA.

Elastin Arteriopathy and William Syndrome: Do You Feel Lucky?

To the Editor: Over the past 2 yr, we have anesthetized 10 patients with Williams syndrome and concur with the recommendations by Burch et al.1 in their recent article. In addition, we have additional suggestions based on the successful resuscitation of two infants who suffered a cardiac arrest under anesthesia. In both infants, induction of anesthesia was with incremental doses of sevoflurane (2% and 3%), a remifentanil infusion and rocuronium. Cardiac arrest occurred within 5 min of induction and before intubation. The electrocardiograms demonstrated marked ST segment depression that was followed soon after by bradycardia. Neither patient had discernible systemic output (no palpable or Doppler evidence of pulses). Resuscitation with phenylephrine, epinephrine, and small fluid boluses occurred during the institution of cardiopulmonary resuscitation. Within 5 min from the start of resuscitation, the transthoracic echocardiography (TTE) demonstrated biventricular akinesis in the first and severe biventricular hypokinesis in the second patient. We used TTE to guide our therapy, allowing us to monitor wall motion abnormalities, guide fluid administration, and carefully titrate vasopressors without worsening tachycardia or the dynamic component of subarterial outflow tract obstruction. In addition, we avoided administration of epinephrine once the rhythm returned, but pulses were still absent (pulseless electrical activity) because the TTE demonstrated severely hypertrophied, underfilled ventricles. In this population, the inappropriate administration of epinephrine as per the pediatric advanced life support protocol for pulseless electrical activity could have compromised recovery. The second patient required urgent extracorporeal membrane oxygenation cannulation after sustaining another cardiac arrest several hours after arrival in the pediatric intensive care unit within 3 min after receiving a 1 μg/kg dose of fentanyl. Both the patients underwent successful surgical repair. These patients had severe bilateral outflow track obstruction with what Stamm et al.2 have termed “macaroni pulmonary arteries” (Fig. 1). It is noteworthy that the presence of an intracardiac shunt (patent foramen ovale and small restrictive ventricular septal defect) did not decrease the risk of arrest.Figure 1.: The PA hypoplasia.Despite an induction technique designed to minimize changes in coronary perfusion, our experience demonstrates that these patients continue to have a very high-anesthetic risk of cardiac arrest. We postulate that, during induction, a decrease in coronary perfusion pressure occurred secondary to vasodilation and in combination with relative hypovolemia, and severe biventricular hypertrophy precipitated ischemia leading to cardiac arrest. In the second patient, a cardiac arrest occurred within minutes after a small dose of fentanyl, highlighting the precarious hemodynamic balance of these children. We recommend preinduction hydration, ideally with an IV, but at minimum liberal PO fluids until 2 h preinduction and the early use of TTE to help treat hemodynamic abnormalities and guide therapy. Denise C. Joffe, MD Michael Richards, BM Michael Eisses, MD Brian Emerson, MD Jeremy Geiduschek, MD Department of Pediatric Anesthesiology University of Washington Seattle, Washington [email protected]

Laparoscopic cholecystectomy under segmental thoracic spinal anaesthesia: a feasibility study

Laparoscopic surgery is normally performed under general anaesthesia, but regional techniques have been found beneficial, usually in the management of patients with major medical problems. Encouraged by such experience, we performed a feasibility study of segmental spinal anaesthesia in healthy patients. Twenty ASA I or II patients undergoing elective laparoscopic cholecystectomy received a segmental (T10 injection) spinal anaesthetic using 1 ml of bupivacaine 5 mg ml-1 mixed with 0.5 ml of sufentanil 5 microg ml-1. Other drugs were only given (systemically) to manage patient anxiety, pain, nausea, hypotension, or pruritus during or after surgery. The patients were reviewed 3 days postoperatively by telephone. The spinal anaesthetic was performed easily in all patients, although one complained of paraesthesiae which responded to slight needle withdrawal. The block was effective for surgery in all 20 patients, six experiencing some discomfort which was readily treated with small doses of fentanyl, but none requiring conversion to general anaesthesia. Two patients required midazolam for anxiety and two ephedrine for hypotension. Recovery was uneventful and without sequelae, only three patients (all for surgical reasons) not being discharged home on the day of operation. This preliminary study has shown that segmental spinal anaesthesia can be used successfully and effectively for laparoscopic surgery in healthy patients. However, the use of an anaesthetic technique involving needle insertion into the vertebral canal above the level of termination of the spinal cord requires great caution and should be restricted in application until much larger numbers of patients have been studied.

Pre-anesthetic evaluation can play a crucial role in the determination of airway management in a child with oropharyngeal tumor

We experienced a case of a huge hemangioma occupying the oropharyngeal space in an 11-year-old child. Although urgent surgical tracheostomy under local anesthesia was suggested initially, medical interview and findings of computerized tomography and fiberoptic laryngoscopy revealed that the airway of the patient was relatively stable when she was in the semi-left decubitus position. General anesthetic induction would have had potential risks of airway obstruction. Thus, after placing the patient in the semi-left decubutus position, we chose semi-awake induction to secure the airway. With a small dose of fentanyl, we accomplished orotracheal intubation. In this report, we discuss the importance of referring to an airway management algorithm when encountering a difficult airway.

Meperidine-Induced Muscular Rigidity During Spinal Anesthesia?

To the Editor: Opioid-induced muscular rigidity has become a well-known phenomenon since it was first described in 1953 (1). It has not been reported during spinal anesthesia. We report a case in which severe muscular rigidity apparently induced by IV meperidine occurred in a patient during spinal anesthesia. A 17-yr-old man (167 cm, 52 kg), whose medical history was not elicited, underwent an emergency appendectomy under spinal anesthesia. Before anesthesia, we administered 0.1 mg of fentanyl and 10 mg metoclopramide for sedation and prophylaxis of emesis, respectively. We then administered 4 mL of 0.5% isobaric bupivacaine intrathecally at the L3-4 interspace using a 27-gauge Whitacre spinal needle. Sensory block up to the level of Th2 was obtained, with complete abdominal wall relaxation and lower limb paralysis but without respiratory discomfort. We administered additional 0.2 mg fentanyl intermittently. Approximately 20 min into the operation, the patient shivered slightly, with the shivering gradually becoming more prominent over the next 10 min. We administered diazepam (5 mg) and meperidine (50 mg) IV, which caused the shivering to immediately disappear. However, after a few more minutes, the patient developed rigidity of the neck, masseter, upper extremities, thoracoabdominal region, and thighs. In particular, the abdominal wall’s rigidity markedly increased his intraabdominal pressure, causing much of the small intestine to extrude from the surgical incision. We discontinued the surgery. Because marked muscle rigidity remained, we induced general anesthesia, propofol, and succinylcholine, and successfully tracheally intubated the patient. Muscular rigidity immediately disappeared, and we resumed the operation. Subsequently, we used both spinal and general anesthesia for this patient, maintaining general anesthesia with 1%–1.5% sevoflurane in 2 L/min of oxygen and 2 L/min of air. The patient’s body temperature and end-tidal carbon dioxide tension remained between 38.0°C–38.2°C and 35–45 mm Hg, respectively, throughout anesthesia. Surgery, which lasted 1.5 h, was completed uneventfully without further administration of muscle relaxants being required. The patient was immediately tracheally extubated. Satisfactory analgesia remained from the spinal anesthesia; a pinprick test revealed analgesia up to the level of Th4, with continuing abdominal wall and lower limb paralysis. Meperidine is usually administered at 0.33–0.85 mg/kg or 25–50 mg for the treatment of shivering (2–5); hence the dose used in our case seemed to be appropriate. The muscular rigidity observed in this patient appears to have been induced by meperidine because the rigidity occurred within a few minutes of giving this drug. The differential diagnosis of such rigidity includes malignant hyperthermia and pain-induced agitation resulting from insufficient spinal anesthesia (6). However, such scenarios are unlikely in the presence of normal end-tidal carbon dioxide tension, pyrexia that only reached 38.2°C, and spinal anesthesia that produced an adequate block up to the level of Th2. In the present case, we gave metoclopramide and fentanyl before administering meperidine. Because both drugs are associated with muscular rigidity, they cannot be excluded as a possible cause of the rigidity observed in this case. However, for approximately 30 min after we administered metoclopramide and fentanyl, until we gave meperidine, the patient’s response to verbal stimuli was almost normal and complete muscular relaxation was obtained in the abdomen and lower extremities. Although we cannot exclude the possibility that metoclopramide and/or small dose fentanyl enhanced the rigidity, they do not appear to have directly caused it. To the best of our knowledge, opioid-induced muscular rigidity has not been reported during spinal anesthesia. Opioids have been proposed to cause rigidity as a result of their action on the central nervous system at the spinal or supraspinal level. Interestingly, although spinal anesthesia provided a complete nerve conduction blockade up to the level of Th2 in the present case, muscular rigidity obviously extended beyond the neck and upper extremities to the lower abdominal wall. Accordingly, opioid-mediated disinhibition of the central nervous system at a spinal or supraspinal level would not appear to be the sole mechanism of opioid-induced muscular rigidity as is conventionally described (6). In the present case, the establishment of complete muscular relaxation (abdominal wall, thighs) and anesthesia below Th2 until the administration of meperidine suggests that an unknown opioid action on the peripheral nervous system might have been involved in the mechanism of opioid-induced muscular rigidity. Norihito Kitagawa, MD Department of Anesthesiology Tsuruta Clinic for Orthopedic Surgery Ushizu, Saga, Japan [email protected] Mayuko Oda, MD Department of Anesthesiology Saga Memorial Hospital Takagise, Saga, Japan Tadahide Totoki, MD Saga Medical School Hospital Saga Medical School Nabeshima, Saga, Japan

A Policy for Nurse-Administered Analgesic Dosing Through a Patient-Controlled Analgesic Device

Patient-controlled analgesia (PCA) has improved pain management in the hospital setting by decreasing the time it takes for patients to obtain intravenous analgesics and to allow for titration based on activity and level of pain. However, when patients are inappropriate for PCA because of cognitive impairment or physical inabilities, they are unable to obtain analgesics in such a timely manner and must wait longer periods of time for analgesics. In our institution, all of our continuous narcotic infusions are administered using a PCA machine for security purposes. But when the patients needed extra medication, the nurses would have to obtain these medications elsewhere. We developed a policy so that the PCA machine could be used to deliver the extra medication by the nurses when needed. This allows the nurse to perform a pain assessment, determine a need for analgesia, administer the prescribed dose, and document this information without leaving the bedside. When the nurse returns to evaluate the effectiveness of this dose, an additional dose of medication may be administered if indicated. We have found this to be invaluable for unplanned dressing changes, line placements, transfers, and other causes of active pain. It has also been useful for giving small doses of fentanyl to cognitively challenged elderly patients who would otherwise be ineligible for this medication. The outcome is diminished time needed to administer analgesia to the physically and cognitively impaired patients as well as decreasing nursing workload. PCA has replaced intermittent injections of narcotics for most patients. However, for those who are cognitively impaired or physically unable to press a PCA button, they must wait longer for their pain relief. In our institution, we developed a policy that allows nurses to administer narcotics using a PCA machine (Nurse Administered Analgesic Dosing), which decreases the time for medication delivery and improves patient comfort. The purpose of this clinical project is to educate nurses about how to safely use PCA devices to improve the delivery of PRN analgesics.

The Effect of Small Dose Fentanyl on the Emergence Characteristics of Pediatric Patients after Sevoflurane Anesthesia without Surgery

Survey of Anesthesiology: April 2004 - Volume 48 - Issue 2 - p 74-75 doi: 10.1097/01.sa.0000119057.14209.29

Propofol requirement for insertion of cuffed oropharyngeal airway versus laryngeal mask airway with and without fentanyl: a dose-finding study

BackgroundThe cuffed oropharyngeal airway (COPA) is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this prospective, randomized study were to compare the COPA and the laryngeal mask airway (LMA †LMA® is the property of Intavent Limited. †LMA® is the property of Intavent Limited.) in terms of propofol requirement with and without fentanyl pretreatment for smooth insertions.MethodsSeventy-five patients undergoing general anaesthesia were randomly assigned to either a COPA (n=38) or LMA (n=37) group for airway management, and each group was further randomized to a saline-propofol or fentanyl-propofol group for anaesthesia induction. The saline-propofol group received i.v. saline and the fentanyl-propofol group received i.v. fentanyl 1 μg kg−1 followed 30 s later by i.v. propofol. Insertion of the device was attempted 90 s after propofol administration without the use of neuromuscular blocking agents or other adjuvants, and the responses of ‘movement’ or ‘no movement’ were judged by three observers blinded to the drug dose. Each dose of propofol at which insertion was attempted was predetermined by modification of Dixon's up-and-down method with 0.5 mg kg−1 as the step size, and 2 mg kg−1 as an initial dose.ResultsWithout fentanyl pretreatment, propofol requirement [mean (sd), 95% CI] for COPA placement [2.17 (0.38), 1.77–2.56 mg kg−1] was significantly less than for LMA insertion [3.42 (0.26), 3.15–3.69 mg kg−1, P<0.001]. In contrast, propofol requirements after fentanyl were comparable between the COPA and LMA groups [1.50 (0.42), 1.06–1.94 and 1.42 (0.26), 1.15–1.69 mg kg−1, respectively], but were less than for the placebo group with both devices (P<0.05). Haemodynamic changes and duration of apnoea were similar with both devices irrespective of fentanyl pretreatment.ConclusionsInsertion of the COPA can be accomplished with a smaller bolus dose of propofol compared with the LMA, but propofol requirements are similar with both devices after a small dose of fentanyl. The cuffed oropharyngeal airway (COPA) is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this prospective, randomized study were to compare the COPA and the laryngeal mask airway (LMA †LMA® is the property of Intavent Limited. †LMA® is the property of Intavent Limited.) in terms of propofol requirement with and without fentanyl pretreatment for smooth insertions. Seventy-five patients undergoing general anaesthesia were randomly assigned to either a COPA (n=38) or LMA (n=37) group for airway management, and each group was further randomized to a saline-propofol or fentanyl-propofol group for anaesthesia induction. The saline-propofol group received i.v. saline and the fentanyl-propofol group received i.v. fentanyl 1 μg kg−1 followed 30 s later by i.v. propofol. Insertion of the device was attempted 90 s after propofol administration without the use of neuromuscular blocking agents or other adjuvants, and the responses of ‘movement’ or ‘no movement’ were judged by three observers blinded to the drug dose. Each dose of propofol at which insertion was attempted was predetermined by modification of Dixon's up-and-down method with 0.5 mg kg−1 as the step size, and 2 mg kg−1 as an initial dose. Without fentanyl pretreatment, propofol requirement [mean (sd), 95% CI] for COPA placement [2.17 (0.38), 1.77–2.56 mg kg−1] was significantly less than for LMA insertion [3.42 (0.26), 3.15–3.69 mg kg−1, P<0.001]. In contrast, propofol requirements after fentanyl were comparable between the COPA and LMA groups [1.50 (0.42), 1.06–1.94 and 1.42 (0.26), 1.15–1.69 mg kg−1, respectively], but were less than for the placebo group with both devices (P<0.05). Haemodynamic changes and duration of apnoea were similar with both devices irrespective of fentanyl pretreatment. Insertion of the COPA can be accomplished with a smaller bolus dose of propofol compared with the LMA, but propofol requirements are similar with both devices after a small dose of fentanyl.

Propofol requirement for insertion of cuffed oropharyngeal airway versus laryngeal mask airway with and without fentanyl: a dose-finding study

The cuffed oropharyngeal airway (COPA) is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this prospective, randomized study were to compare the COPA and the laryngeal mask airway (LMA) in terms of propofol requirement with and without fentanyl pretreatment for smooth insertions. Seventy-five patients undergoing general anaesthesia were randomly assigned to either a COPA (n=38) or LMA (n=37) group for airway management, and each group was further randomized to a saline-propofol or fentanyl-propofol group for anaesthesia induction. The saline-propofol group received i.v. saline and the fentanyl-propofol group received i.v. fentanyl 1 micro g kg(-1) followed 30 s later by i.v. propofol. Insertion of the device was attempted 90 s after propofol administration without the use of neuromuscular blocking agents or other adjuvants, and the responses of 'movement' or 'no movement' were judged by three observers blinded to the drug dose. Each dose of propofol at which insertion was attempted was predetermined by modification of Dixon's up-and-down method with 0.5 mg kg(-1) as the step size, and 2 mg kg(-1) as an initial dose. Without fentanyl pretreatment, propofol requirement [mean (SD), 95% CI] for COPA placement [2.17 (0.38), 1.77-2.56 mg kg(-1)] was significantly less than for LMA insertion [3.42 (0.26), 3.15-3.69 mg kg(-1), P<0.001]. In contrast, propofol requirements after fentanyl were comparable between the COPA and LMA groups [1.50 (0.42), 1.06-1.94 and 1.42 (0.26), 1.15-1.69 mg kg(-1), respectively], but were less than for the placebo group with both devices (P<0.05). Haemodynamic changes and duration of apnoea were similar with both devices irrespective of fentanyl pretreatment. Insertion of the COPA can be accomplished with a smaller bolus dose of propofol compared with the LMA, but propofol requirements are similar with both devices after a small dose of fentanyl.

Effects of Intrathecal Fentanyl on Bupivacaine Spinal Blockade for Urologic Surgery

Background: Opioids are increasingly being administered intrathecally as adjuncts to local anesthetics. They enhance spinal anesthesia without prolonging motor recovery. We evaluated the effect of 10 of fentanyl to bupivacaine on sensory, motor block and side effects. Methods: Thirty six patients undergoing urologic surgery were randomized into two groups. Control group received bupivacaine 10 mg combined with normal saline 0.2 ml, and Fentanyl group received bupivacaine 10 mg with fentanyl 10 (0.2 ml). Results: There were no significant differences between two groups in the peak level of sensory block, onset of peak level, duration of motor block, and side effects. However, the time of regression from peak level to T10 in Fentanyl group was longer significantly than that of Control group. Conclusions: Intrathecal small dose fentanyl (10) on bupivacaine spinal blockade prolonged duration of sensory block and did not augment side effects and provide reliable anesthesia for urologic surgery.