Marie T. Aouad

Effect of low‐dose dexmedetomidine or clonidine on the characteristics of bupivacaine spinal block

Background:  The purpose of this study was to compare the onset and duration of sensory and motor block, as well as the hemodynamic changes and level of sedation, following intrathecal bupivacaine supplemented with either dexmedetomidine or clonidine.

Preoxygenation: Comparison of Maximal Breathing and Tidal Volume Breathing Techniques

BACKGROUND Preoxygenation with tidal volume breathing for 3-5 min is recommended by Hamilton and Eastwood. This report compares tidal volume preoxygenation technique with deep breathing techniques for 30-60 s. METHODS The study was conducted in two parts on patients undergoing elective coronary bypass grafting. In the first group (n = 32), each patient underwent all of the following preoxygenation techniques: the traditional technique consisting of 3 min of tidal volume breathing at an oxygen flow of 5 l/min; four deep breaths within 30 s at oxygen flows of 5 l/min, 10 l/min, and 20 l/min; and eight deep breaths within 60 s at an oxygen flow of 10 l/min. The mean arterial oxygen tensions after each technique were measured and compared. In the second group (n = 24), patients underwent one of the following techniques of preoxygenation: the traditional technique (n = 8), four deep breaths (n = 8), and eight deep breaths (n = 8). Apnea was then induced, and the mean times of hemoglobin desaturation from 100 to 99, 98, 97, 96, and 95% were determined. RESULTS In the first group of patients, the mean arterial oxygen tension following the tidal breathing technique was 392+/-72 mm Hg. This was significantly higher (P<0.05) than the values obtained following the four deep breath technique at oxygen flows of 5 l/min (256+/-73 mm Hg), 10 l/min (286+/-69 mm Hg), and 20 l/min (316+/-67 mm Hg). In contrast, the technique of eight deep breaths resulted in a mean arterial oxygen tension of 369+/-69 mm Hg, which was not significantly different from the value achieved by the traditional technique. In the second group of patients, apnea following different techniques of preoxygenation was associated with a slower hemoglobin desaturation in the eight-deep-breaths technique as compared with both the traditional and the four-deep-breaths techniques. CONCLUSION Rapid preoxygenation with the eight deep breaths within 60 s can be used as an alternative to the traditional 3-min technique.

A single dose of propofol at the end of surgery for the prevention of emergence agitation in children undergoing strabismus surgery during sevoflurane anesthesia

Background:Emergence agitation in children after sevoflurane is common. Different drugs have been used to decrease its occurrence with variable efficacy. The authors compared the incidence and severity of emergence agitation in children who received a single dose of propofol at the end of strabismus surgery versus children who received saline. Methods:In this prospective, randomized, double-blind study, the authors enrolled 80 healthy children aged 2–6 yr. The children were randomly allocated to the propofol group (n = 41), which received 1 mg/kg propofol at the end of surgery, or to the saline group (n = 39), which received saline. Results:The mean scores on the Pediatric Anesthesia Emergence Delirium scale were significantly lower in the propofol group compared with the saline group (8.6 ± 3.9 vs. 11.5 ± 4.5; P = 0.004). Also, the incidence of agitation was significantly lower in the propofol group compared with the saline group (19.5% vs. 47.2%; P = 0.01). A threshold score greater than 10 on the Pediatric Anesthesia Emergence Delirium scale was the best discriminator between presence and absence of emergence agitation. Times to removal of the laryngeal mask airway (10.6 ± 1.5 vs. 9.4 ± 1.9 min; P = 0.004) and emergence times (23.4 ± 5.7 vs. 19.7 ± 5 min; P = 0.004) were significantly longer in the propofol group. However, discharge times were similar between the two groups (propofol: 34.1 ± 8.4 min; saline: 34.9 ± 8.6 min). More parents in the propofol group were satisfied. Conclusions:In children undergoing strabismus surgery, 1 mg/kg propofol at the end of surgery after discontinuation of sevoflurane decreases the incidence of agitation and improves parents’ satisfaction without delaying discharge from the postanesthesia care unit.

The Analgesic Efficacy of Subarachnoid Morphine in Comparison with Ultrasound-Guided Transversus Abdominis Plane Block After Cesarean Delivery: A Randomized Controlled Trial

BACKGROUND: Ultrasound-guided transversus abdominis plane block is an effective method of providing pain relief after cesarean delivery. Neuraxial morphine is currently the “gold standard” treatment for pain after cesarean delivery. In this study we tested the hypothesis that subarachnoid morphine would provide more prolonged and superior analgesia than would transversus abdominis plane block in patients undergoing elective cesarean delivery. METHODS: In this prospective, double-blind study, 57 patients were randomly assigned to receive either subarachnoid morphine (group SAM; n = 28) or transversus abdominis plane block (group TAP; n = 29). Patients received bupivacaine spinal anesthesia combined with morphine 0.2 mg in group SAM and received saline in group TAP. At the end of surgery, bilateral transversus abdominis plane block was performed using saline in group SAM or using bupivacaine 0.375% plus epinephrine 5 &mgr;g/mL in group TAP with 20 mL on each side. Postoperative analgesia for the first 24 hours consisted of scheduled rectal diclofenac and IV paracetamol; breakthrough pain was treated with IV tramadol. For the next 24 hours, scheduled rectal diclofenac was given; oral paracetamol and IV tramadol were administered upon patient request. Patients were assessed postoperatively in the postanesthesia care unit (time 0 hours) and at 2, 4, 6, 12, 24, 36, and 48 hours. The primary outcome measure was the time to first analgesic request. RESULTS: Median (range) time to first analgesic request was longer in group SAM than in group TAP [8 (2–36) hours versus 4 (0.5 to 29) hours (P = 0.005)]. Median (range) number of tramadol doses received between 0 and 12 hours was 0 (0–1) in group SAM versus 0 (0–2) in group TAP (P = 0.03). Postoperative visceral pain scores at rest and on movement during first the 4 hours were lower in group SAM than in group TAP, but were not different at any other time points. The incidence of moderate to severe nausea was higher in group SAM than in group TAP [13/28 (46%) versus 5/29 (17%) (P = 0.02)]. More patients developed pruritus requiring treatment in group SAM than in group TAP [(11/28 (39%) versus none (0%) (P < 0.001)]. CONCLUSION: As part of a multimodal analgesic regimen, subarachnoid morphine provided superior analgesia when compared with ultrasound-guided transversus abdominis plane block after cesarean delivery, yet at the cost of increased side effects.

Diclofenac and/or propacetamol for postoperative pain management after cesarean delivery in patients receiving patient controlled analgesia morphine.

Background and Objectives A multimodal approach to postcesarean pain management may enhance analgesia and reduce side effects after surgery. This study evaluates the postoperative analgesic effects of propacetamol and/or diclofenac in parturients undergoing elective cesarean delivery under spinal anesthesia. Methods After randomization, 80 healthy parturients received the following: placebo (group M), 100 mg diclofenac rectally every 8 hours (group MD), 2 g propacetamol intravenously every 6 hours (group MP), or a combination of 2 g propacetamol and 100 mg diclofenac (group MDP) as described above. Drugs were administered for 24 hours after surgery. Postoperative pain was controlled with a patient controlled analgesia pump, using morphine. The visual analog scale (VAS) at rest and on coughing, as well as the morphine consumption, were evaluated at 2, 6, and 24 hours postoperatively. Also, the side effects experienced after undergoing the different regimens were compared. Results The patients’ characteristics did not differ significantly between the 4 groups. VAS score at 2 hours, both at rest and on coughing were lower in group MDP and MD compared with group M (P < .05). At 24 hours, there was still a tendency toward lower pain scores in the groups MDP and MD; however, this difference was only statistically significant at rest between the MDP group and the MP and M groups. Morphine consumption at 2, 6, and 24 hours was lower in the MDP and MD groups compared with the MP and M groups (P < .05). The morphine-sparing effect was higher in groups MDP and MD compared with group MP (57% and 46%, respectively, v 8.2%, P < .05). The incidence of side effects was similar in all groups. However, the power of the study was too low to permit an evaluation of potential side effects. Conclusion Diclofenac after cesarean delivery improves analgesia and has a highly significant morphine-sparing effect. We were unable to demonstrate significant morphine-sparing effect of propacetamol or additive effect of propacetamol and diclofenac in this group of patients.

The effect of dexamethasone on postoperative vomiting after tonsillectomy.

UNLABELLED In this double-blinded, randomized, placebo-controlled study, we assessed the effect of dexamethasone 0.5 mg/kg IV administered preoperatively in 110 children 2-12 yr old, undergoing electrodissection adenotonsillectomy, using a standardized anesthetic technique. The incidence of early and late vomiting, the time to first oral intake, the quality of oral intake, the satisfaction scores, and the duration of IV hydration were compared in both groups. The overall incidence of vomiting, as well as the incidence of late vomiting, was significantly less in the Dexamethasone group as compared with the Saline group (23% and 19% vs 51% and 34%, respectively). The time to first oral intake and the duration of IV hydration were shorter in the Dexamethasone group compared with the Saline group (P < 0.05). The quality of oral intake and the satisfaction scores were better in the Dexamethasone group than in the Saline group (P < 0.05). This report confirms the beneficial effect of IV dexamethasone on both vomiting and oral intake in children undergoing electrodissection adenotonsillectomy. IMPLICATIONS In this double-blinded, placebo-controlled study, we examined the efficacy of a single dose of dexamethasone 0.5 mg/kg IV on posttonsillectomy vomiting and oral intake in children 2-12 yr old. Dexamethasone significantly decreased the incidence of postoperative vomiting during the first 24 h, shortened the time to the first oral intake and the duration of IV hydration, and improved the quality of oral intake and the satisfaction scores of the patients.

Preoperative caudal block prevents emergence agitation in children following sevoflurane anesthesia

Background:  The frequency of emergence agitation in children is increased following sevoflurane anesthesia. However, controversies still exist concerning the exact etiology of this postanesthetic problem. Although this phenomenon is present with adequate pain relief or even following pain‐free procedures, pain is still regarded as a major contributing factor.

Emergence agitation in children: an update

Purpose of review In this review, the most recent and relevant developments in the field of emergence agitation in children, as related to its assessment, etiology, and management, are discussed. Recent findings Studies have shown that a more specific assessment tool is needed to decrease measurement errors. Such scales have been developed recently and incorporate cognitive-related assessment items in addition to agitation behaviors. Young, emotional, impulsive and less social children with anxious parents undergoing head and neck surgery are identified to be at risk for the development of emergence agitation. Factors that may influence the occurrence of this postanesthetic behavior include the level of preoperative anxiety and premedication, anesthesia drugs, as well as awakening in a hostile environment and feeling pain. Management include ruling out all possible causes, such as physiologic compromise, physical discomfort and pain. Treatment of emergence agitation is usually not required since the condition is self-limiting. If unremitting, however, treatment with opioids, benzodiazepines or small doses of hypnotics may be required. Summary It is recommended that children at high risk are identified in order to decrease their level of preoperative anxiety, to supplement low-solubility inhalational agents with adjuvant drugs, to prevent postoperative pain and to allow parents to be with their children during recovery from anesthesia.

The effect of low-dose remifentanil on responses to the endotracheal tube during emergence from general anesthesia.

BACKGROUND: Emergence from general anesthesia can be associated with coughing, agitation, and hemodynamic disturbances. Remifentanil may attenuate these responses. METHODS: In a prospective, double-blind, randomized trial, we enrolled 60 adult patients undergoing nasal surgery using remifentanil-based anesthesia. During the emergence phase, the remifentanil group had remifentanil reduced to one tenth of the maintenance rate, whereas the control group had remifentanil discontinued. RESULTS: Times to awakening and tracheal extubation were similar between the two groups. During emergence, the remifentanil group (infusion rate 0.014 ± 0.011 &mgr;g · kg−1 · min−1) had a significantly lower incidence (40% vs 80%, P = 0.002) and less severe coughing compared with the control group, as well as a lower incidence of nonpurposeful movement (3.3% vs 30%, P = 0.006) and slower heart rates. CONCLUSIONS: Low-dose remifentanil during emergence did not prolong wake-up but reduced the incidence and severity of coughing from the endotracheal tube.

Hydroxyethylstarch 10% is superior to Ringer’s solution for preloading before spinal anesthesia for Cesarean section

Purpose: To compare the preloading effect of 500 ml hydroxyethylstarch (HES) 10% with I L Lactated Ringer’s solution (LR).Methods: In 40 healthy women undergoing elective Cesarean section HES, 500 ml (n=20), or LR, IL (n=20), was administered during 10 min before spinal anesthesia. The incidence of hypotension, (systolic blood pressure <80% of baseline and <100 mm Hg), and the amount of ephedrine used to treat it were compared. Also, the incidence of nausea and/or vomiting were recorded. Neonatal outcome was assessed using Apgar scores and umbilical venous and arterial blood gases.Results: The incidence of hypotension was higher in the LR than in HES group (80%vs 40%). Mean minimum systolic blood pressure was lower in the LR than in the HES group (86.1±12.7 mm Hgvs 99.6±9.7 mm HgP<0.05). Systolic blood pressure <90 mmHg occurred in two of 20 patients (10%) who received HESvs 11 of 20 patients (55%) who received LR (P<0.05). More doses of ephedrine were required to treat hypotension in the Lr than in the HES group (35.3±18.4 mgvs 10.6±8.6 mg;P<0.05). The incidence of nausea and/or vomiting was lower in the HES than in the crystalloid group. Neonatal outcome was good and similar in both groups.Conclusion: Preloading patients undergoing elective Cesarean section with 500 ml HES 10%, decreases the incidence and severity of spinal-induced hypotension more than preloading with I L of LR solution.RésuméObjectif: Comparer l’effet d’une précharge de 500 ml d’hydroxyéthylamidon (HEA) à 10 % avec celui de I L de solution de lactate de Ringer (LR).Méthode: Pendant 10 min avant la rachianesthésie, on a administré chez 40 femmes qui devaient subir une césarienne 500 ml d’HEA (n=20) ou I L de LR (n=20). L’incidence d’hypotension (tension artérielle <80 % de la mesure de base et <100 mmHg) et la quantité d’éphédrine utilisée pour la traiter ont été comparées. De plus, l’incidence de nausées et/ou de vomissements a été enregistrée. L’indice d’Apgar et l’analyse des gaz du sang veineux et artériel ombilical ont permis d’évaluer les nouveau-nés.Résultats: On a noté une plus grande incidence d’hypotension avec le LR qu’avec l’HEA (80 %vs 40 %). La moyenne des mesures de tension artérielle systolique minimale était plus basse dans le groupe LR que dans le groupe HEA (86,1±12,7 mmHgvs 99,6±9,7 mmHgP <0,05). La tension artérielle systolique <90 mmHg est survenue chez deux des 20 patientes (10 %) qui ont reçu de l’HEAvs 11 des 20 patientes (55 %) qui ont reçu du LR (P <0,05). Le traitement de l’hypotension a nécessité plus d’éphédrine dans le groupe LR que dans le groupe HEA (35,3±18,4 mgvs 10,6±8,6 mg;P <0,05). L’incidence de nausées et/ou de vomissements a été plus faible avec l’HEA qu’avec le cristalloïde. L’évaluation néonatale a été satisfaisante et similaire dans les deux groupes.Conclusion: Une précharge de 500 ml d’HEA à 10 % chez des patientes qui vont subir une césarienne diminue plus l’incidence et la sévérité de l’hypotension induite par la rachianesthésie qu’une précharge avec I L de solution de LR.