Pamela Angle

A randomized controlled trial examining the effect of naproxen on analgesia during the second day after cesarean delivery.

Whereas nonsteroidal antiinflammatory drugs augment spinal morphine on Day l, the analgesia gained by simply combining these drugs with conventional “on request” oral regimens on Day 2 is less clear. In this trial, we randomized 80 women undergoing elective cesarean delivery with spinal morphine (0.2 mg) to receive naproxen (500 mg) or placebo every 12 h after surgery. Both groups received conventional therapy with acetaminophen with codeine (on request) and rescue IM opioids. Incision pain on sitting (IPS), incision pain at rest, uterine cramping, and gas pain were evaluated with visual analog scales (0–100). Worst interval pain (0–10), analgesic use, and side effects were measured over 72 h. At 36 h (primary outcome), naproxen use was associated with reductions in IPS (38.2 ± 26.0 versus 51.4 ± 25.7;P = 0.05), incision pain at rest, uterine cramping, and worst interval pain scores. Clinically modest, statistically significant reductions in IPS (P = 0.0001) and opioid use were found over time (P < 0.0l). Reductions in the incidence of inadequate analgesia and improvements in overall pain relief (P = 0.0006) on Day l did not persist on Day 2 (overall pain relief, P = 0.057; inadequate analgesia, 24% naproxen versus 27% controls;P = 1.00). The addition of regular doses of naproxen to conventional oral pain therapy after cesarean delivery leads to reductions in IPS at 36 h and pain over Day 2 but does not reduce the incidence of inadequate analgesia.

Dural tissue trauma and Cerebrospinal fluid leak after epidural needle puncture: Effect of needle design, angle, and bevel orientation

Background The effects of epidural needle design, angle, and bevel orientation on cerebrospinal fluid leak after puncture have not been reported. The impact of these factors on leak rate was examined using a dural sac model. Dural trauma was examined using scanning electron microscopy. Methods Human cadaveric dura, mounted on a cylindrical model, was punctured with epidural needles using a micromanipulator. Tissue was punctured at 15 cm H2O (left lateral decubitus) system pressure, and leak was measured at 25 cm H2O (semisitting) pressure. Leak rates and trauma were compared for the following: (1) six different epidural needles at 90°, bevel parallel to the dural long axis; (2) 18-gauge Tuohy and 18-gauge Special Sprotte® epidural needles, 30°versus 90°; (3) 18-gauge Tuohy, bevel perpendicular versus parallel to the dural long axis. Results With the 90° puncture, bevel parallel, the greatest leak occurred with a 17-gauge Hustead (516 ± 319 ml/15 min), and the smallest leak occurred with a 20-gauge Tuohy (100 ± 112 ml/15 min; P = 0.0018). A 20-gauge Tuohy puncture led to statistically significant reductions in leak (P value range, 0.0001–0.0024) compared with all needles except the Special Sprotte®. With the 30°versus 90° angle, 30° punctures with an 18-gauge Tuohy produced nonstatistically significant leak reductions compared with the 18-gauge Tuohy at 90°. The puncture angle made no difference for the Special Sprotte®. Nonsignificant reductions were found for the Special Sprotte® compared with the Tuohy. With the 18-gauge Tuohy bevel orientation, perpendicular orientation produced nonstatistically significant reductions in leak compared with parallel orientation. Conclusions Cerebrospinal fluid leak after puncture was influenced most by epidural needle gauge. Leak rate was significantly less for the 20-gauge Tuohy needle.

Conversion of epidural labour analgesia to anaesthesia for Caesarean section: a prospective study of the incidence and determinants of failure

BACKGROUND The incidence of general anaesthesia (GA) has been used as a marker for the quality of obstetric anaesthesia care. Recent guidelines suggest the rate of GA for Caesarean section in parturients with pre-existing epidural analgesia for labour should be <3%. The primary purpose of this study is to determine whether or not this is an achievable standard in a university teaching hospital. We also wished to determine the factors influencing the incidence of inadequate anaesthesia. METHODS We studied a consecutive cohort of 501 patients who had a Caesarean section after epidural labour analgesia. The incidence of GA, the total incidence of failure, and the factors previously associated with failure were recorded. Factors shown to be significant with univariate analysis were used in a binary logistic regression to determine the independent risk factors for failure. RESULTS Twenty-one of 501 parturients required GA (4.1%, 95% confidence interval 2.6-6.3%), not significantly different from 3% (P=0.1). Fifteen of 21 (71%) of these occurred intraoperatively. The total rate of failure was 30/501 (5.9%, 95% confidence interval 4.0-8.4%). Maternal height and the number of clinician top-ups in labour were the significant independent risk factors for failure. CONCLUSIONS Intraoperative conversion to GA may increase both maternal and fetal risks. Strategies to reduce the incidence may include early recognition of inadequate labour analgesia and reliable assessment of adequacy of surgical anaesthesia.

Epidural catheter penetration of human dural tissue: in vitro investigation.

Background: Factors contributing to subarachnoid catheter passage after epidural placement are not well understood. This study explored mechanisms that might explain its occurrence. Methods: Human cadaveric dura was mounted on a model and pressurized to physiologic levels. In a standardized fashion, a 20-gauge Portex® three-port, closed end (nonflexible) tip catheter was passed through an epidural needle mounted on a micromanipulator at a 90° angle, attempting to penetrate dura with the catheter. Attempts then followed with a 19-gauge Arrow Flex Tip Plus® single-port catheter. Subarachnoid catheter passage was compared in (1) intact dura, (2) clinically occult versus obvious epidural needle punctures, and (3) single 25-gauge Whitacre® spinal needle punctures after combined spinal–epidural placement. Results: Neither catheter penetrated intact dura: Portex, 0 of 300 attempts (0.0000; 95% confidence interval [CI]: 0.0000, 0.0158); Arrow, 0 of 300 attempts (0.0000; 95% CI: 0.0000, 0.0158). In clinically occult epidural needle punctures, the 20-gauge Portex catheter penetrated 1 of 3 specimens in 1 of 14 attempts (0.0714; 95% CI: 0.0021, 0.3583). The 19-gauge Arrow did not pass (0 of 15 attempts, 0.0000; 95% CI: 0.0000, 0.2535). In clinically obvious epidural needle punctures, the Portex passed in 6 of 33 attempts (0.1818; 95% CI: 0.0760, 0.3608) and the Arrow passed in 1 of 35 attempts (0.0286; 95% CI: 0.0012, 0.1662). Neither catheter passed through a single 25-gauge spinal needle puncture after an uncomplicated combined spinal–epidural: Portex, 0 of 90 attempts (0.0000; 95% CI: 0.0000, 0.0510); Arrow, 0 of 90 attempts (0.0000; 95% CI: 0.0000, 0.0510). Conclusions: Catheter passage is unlikely in the presence of intact dura or after an uncomplicated combined spinal–epidural. Unintentional subarachnoid passage suggests dural damage with the epidural needle.

The effect of epidural needle type on postdural puncture headache: a randomized trial

PurposeA prospective, randomized trial in labouring parturients was undertaken to assess whether the 18G Special Sprotte™ epidural needle is associated with a lower incidence of accidental dural puncture (ADP) in comparison with the 17G Tuohy needle. A secondary purpose was to determine if the incidence of postdural puncture headache (PDPH ) differed between groups when ADP occurred.MethodsFollowing Institutional Review Board approval 1,077 parturients requesting epidural analgesia at three tertiary obstetrical units were randomized to epidural catheter insertion with a 17G Tuohy or 18G Special Sprotte™ needle. Patients were followed for seven days by a blinded assessor to determine the occurrence of PDPH using standardized criteria. If postural headache or neck ache presented, an ADP was diagnosed even if cerebrospinal fluid (CSF) was not observed at insertion. This subgroup was followed daily to assess headache characteristics and response to blood patch.ResultsSix Tuohy group patients, and two patients in the Sprotte group were excluded. One of the six excluded in the Tuohy group had an ADP. Twenty-eight ADPs occurred, nine unrecognized by CSF visualization (1.8% Tuohy, 3.4% Sprotte, P = 0.12). The incidence of unrecognized ADPs was higher in the Sprotte group (40% Sprotte vs 20% Tuohy, P < 0.05). If ADP occurred, the incidence of PDPH was lower in the Sprotte group (100% Tuohy vs 55% Sprotte, P = 0.025). The ease of use, and user satisfaction were higher in the Tuohy group (84 ± 17.3% Tuohy vs 68.2 ± 25.3% Sprotte, P < 0.001).ConclusionThe incidence of ADP was not reduced with the Special Sprotte™ epidural needle in comparison with the Tuohy needle, but PDPH after ADP occurred less frequently in the Sprotte group.RésuméObjectifUne étude prospective randomisée a été réalisée chez des parturientes en travail pour évaluer si ľaiguille de péridurale 18G Special Sprotte™ est associée à une plus faible incidence de ponction durale accidentelle (PDA) en comparaison de ľaiguille 17G Tuohy. Un second objectif était de déterminer si ľincidence de céphalées post-ponction durale (CPPD) diffère entre les groupes quand survient une PDA.MéthodeSuivant ľapprobation du Comité ďexamen de ľinstitution, 1 077 parturientes nécessitant une analgésie péridurale dans trois unités obstétricales tertiaires ont été réparties en deux groupes pour ľinsertion ďun cathéter péridural ave une aiguille 17G Tuohy ou une 18G Special Sprotte™. Les femmes ont été suivies pendant sept jours par un évaluateur impartial de ľoccurrence de CPPD selon des critères normalisés. Si des céphalées posturales ou des douleurs au cou survenaient, une PDA était diagnostiquée même si le liquide céphalo-rachidien (LCR) n’était pas visible à ľinsertion. Ce sous-groupe a été suivi quotidiennement pour ľévaluation des caractéristiques des céphalées et la réponse à ľadministration épidurale de sang autologue.RésultatsSix patientes du groupe Tuohy et deux du groupe Sprotte ont été exclues. Une des six exclues du groupe Tuohy présentait une PDA. Il y a eu 28 PDA, dont neuf non reconnues par la visualisation du LCR (1.8 % Tuohy, 3.4 % Sprotte, P = 0,12). Ľincidence de PDA non reconnues a été plus élevée dans le groupe Sprotte (40 % Sprotte vs 20 % Tuohy, P < 0,05). Si une PDA survenait, ľincidence de CPPD était plus faible dans le groupe Sprotte (100 % Tuohy vs 55 % Sprotte, P = 0,025). La facilité ďusage et la satisfaction de ľutilisateur ont été plus élevées dans le groupe Tuohy (84 ± 17,3 % Tuohy vs 68,2 ± 25,3 % Sprotte, P < 0,001).ConclusionĽincidence de PDA n’a pas été réduite avec ľusage de ľaiguille de péridurale Special Sprotte™ comparée à ľaiguille Tuohy, mais les CPPD suivant une PDA ont été moins fréquentes dans le groupe Sprotte.

Anesthetic considerations of parturients with obesity and obstructive sleep apnea

Obstructive sleep apnea (OSA) is characterized by upper airway collapse and obstruction during sleep. It is estimated to affect nearly 5% of the general female population. Obesity is often associated with OSA. The physiological changes associated with pregnancy may increase the severity of OSA with a higher risk of maternal and fetal morbidity. However, very few parturients are diagnosed during pregnancy. These undiagnosed parturients pose great challenge to the attending anaesthesiologist during the perioperative period. Parturients at risk should be screened for OSA, and if diagnosed, treated. This review describes the anaesthetic concerns in obese parturients at risk for OSA presenting to the labor and delivery unit.

Performance of the Angle Labor Pain Questionnaire During Initiation of Epidural Analgesia in Early Active Labor.

BACKGROUND:The Angle Labor Pain Questionnaire (A-LPQ) is a new, 22-item multidimensional psychometric questionnaire that measures the 5 most important dimensions of women’s childbirth pain experiences using 5 subscales: The Enormity of the Pain, Fear/Anxiety, Uterine Contraction Pain, Birthing Pain, and Back Pain/Long Haul. Previous work showed that the A-LPQ has overall good psychometric properties and performance during early active labor in women without pain relief. The current study assessed the tool’s sensitivity to change during initiation of labor epidural analgesia with the standardized response mean (SRM, primary outcome). METHODS:Two versions of the A-LPQ were administered once, in each of 2 test sessions, by the same trained interviewer during early active labor. The sequence of administration was randomized (ie, standard question order version [Test 1] followed by mixed version [Test 2] or vice versa). Test 1 was completed before epidural insertion; Test 2 commenced 20 to 30 minutes after the test dose. Providers assessed/treated pain independently of the study. Sensitivity to change was assessed using SRMs, Cohen’s d, and paired t tests. Overall pain intensity was concurrently examined using Numeric Rating Scale and the Verbal Rating Scale (VRS); coping was assessed with the Pain Mastery Scale. Changes in pain were measured with the Patient Global Impression of Change Scale. Internal consistency was assessed with Cronbach’s &agr;. Concurrent validity with other tools was assessed using Spearman’s rank correlation coefficient. RESULTS:A total of 51 complete datasets were analyzed. Most women reported moderate (63%, 32/51) or severe (18%, 9/51) baseline pain on VRS scores during Test 1; 29% (15/51) reported mild pain, and 6% (3/51) reported moderate pain during Test 2. Approximately 90% (46/51) of women reported much or very much improved pain at the end of testing. Cronbach’s &agr; for A-LPQ summary scores was excellent (0.94) and ranged from 0.78 (acceptable) to 0.92 (excellent) for subscales (Test 1). Large SRMs were found for A-LPQ summary scores (1.6, 95% CI: 1.2, 2.1) and all subscales except the Birthing Pain subscale (moderate, 0.60, 95% CI: 0.23, 0.97). Significant (P < .001) differences were found between A-LPQ summary scores and between all subscales on paired t tests. Correlations between A-LPQ summary and Numeric Rating Scale scores (overall pain intensity) were strong (&rgr; > 0.73), correlations were moderate (&rgr; > 0.5) with VRS scores and coping scores (&rgr; > 0.67). CONCLUSIONS:Findings support A-LPQ use for measurement of women’s childbirth pain experiences during initiation of labor epidural analgesia during early active labor. Combined with our previous work, they also support the use of the A-LPQ in late labor and at delivery.

The Angle Labor Pain Questionnaire: Reliability, Validity, Sensitivity to Change, and Responsiveness During Early Active Labor Without Pain Relief.

Objectives: The Angle Labor Pain Questionnaire (A-LPQ) is a new, condition-specific, multidimensional psychometric instrument that measures the most important dimensions of women’s childbirth pain experiences using 5 subscales: The Enormity of the Pain, Fear/Anxiety, Uterine Contraction Pain, Birthing Pain, and Back Pain/Long Haul. This study assessed the A-LPQ’s test-retest reliability during early active labor without pain relief. Methods: Two versions of the A-LPQ were randomly administered to laboring women during 2 test sessions separated by a 20-minute window. Participants were of mixed parity, contracting ≥3 minutes apart, cervical dilation ⩽6 cm, and without pain relief. Changes in pain were rated using the Patient Global Impression of Change Scale. Overall pain intensity and pain coping were rated using the Numeric Rating Scale (NRS) and the Verbal Rating Scale (VRS) and the Pain Mastery Scale (PMS) respectively. A-LPQ test-retest reliability (primary outcome), Cronbach’s &agr;, and concurrent validity with NRS, VRS, and PMS scores were assessed (n=104). Responsiveness was assessed in 55 women who reported changes in pain. Results: A-LPQ summary and subscale scores demonstrated good test-retest reliability (ICCs, 0.96 to 0.89), trivial to moderate sensitivity to change, and high responsiveness to minimal changes in pain (0.85 to 1.50). Cronbach’s &agr; for A-LPQ summary scores was excellent (0.94) and ranged from 0.72 to 0.94 for subscales. Concurrent validity was supported by moderate to strong correlations with NRS and VRS scores for overall pain intensity and PMS scores for pain coping. Discussion: Findings support A-LPQ use for assessing women’s childbirth pain experiences.

Chronic kidney disease in pregnancy

Parturients with renal insufficiency or failure present a significant challenge for the anesthesiologist. Impaired renal function compromises fertility and increases both maternal and fetal morbidity and mortality. Close communication amongst medical specialists, including nephrologists, obstetricians, neonatologists and anesthesiologists is required to ensure the safety of mother and child. Pre-existing diseases should be optimized and close surveillance of maternal and fetal condition is required. Kidney function may deteriorate during pregnancy, necessitating early intervention. The goal is to maintain hemodynamic and physiologic stability while the demands of the pregnancy change. Drugs that may adversely affect the fetus, are nephrotoxic or are dependent on renal elimination should be avoided.

Preload or Coload for Spinal Anesthesia for Elective Cesarean Delivery: A Meta-analysis

Background Hypotension following spinal anesthesia for Cesarean delivery is common. Fluid loading is recommended to prevent hypotension, but preload is often ineffective. In non-pregnant patients, coloading has been shown to better maintain cardiac output after spinal anesthesia. The purpose of this meta-analysis was to determine whether the timing of the fluid infusion, before (preload) or during (coload) induction of spinal anesthesia for Cesarean delivery, influences the incidence of maternal hypotension or neonatal outcome. Methods We retrieved randomized controlled trials that compared a fluid preload with coload in patients undergoing spinal anesthesia for elective Cesarean delivery. We graded the articles for quality of reporting (maximum score = 5) and recorded the incidence of hypotension, lowest blood pressure, the incidence of maternal nausea and vomiting, umbilical cord pH, and Apgar scores. We combined the results using random effects modelling. Results We retrieved eight studies comprised of 518 patients. The median quality score for the published studies was three. The incidence of hypotension in the coload group was 159/268 (59.3%) compared with 156/250 (62.4%) in the preload group (odds ratio [OR] = 0.93; 95% confidence interval [CI] 0.54‐1.6). There were no significant differences between groups in any of the other outcomes. Conclusions It is unnecessary to delay surgery in order to deliver a preload of fluid. Regardless of the fluid loading strategy, the incidence of maternal hypotension is high. Prophylactic or therapeutic vasopressors may be required in a significant proportion of patients.