Difficult subarachnoid anaesthesia Prediction and Performance

Spinal anesthesia is an old, simple, and popular anesthetic technique, yet much remains unknown regarding pertinent anatomy, physiology, and pharmacology. Investigations into physiologic effects of spinal anesthesia reveal complex actions on multiple organ systems. New local anesthetics, analgesic additives, and techniques are being investigated for different applications as the practice of medicine focuses on outpatient care. Safety of spinal agents and complications from spinal anesthesia continue to be examined and re-examined to improve safety. Further study will be needed to fully resolve these issues and to further understand and improve the clinical use of spinal anesthesia.

Combination spinal analgesic chemotherapy: a systematic review.

In Response: We appreciate Dr. Colclough's thoughtful letter about our paper comparing spinal and epidural anesthesia for cesarean section. However, we disagree with him on several of the issues he raises. Our data and that of other investigators (cited in our paper) demonstrate that spinal anesthesia for cesarean section is faster to perform and has fewer complications, and that patients may experience less discomfort intraoperatively. Dr. Colclough states that many anesthesiologists can place a needle in the epidural space more quickly than they can place a small-gauge spinal needle into the cerebrospinal fluid. We doubt this is the case and are unaware of any research supporting this statement. However, even if an epidural needle can be properly positioned faster than a spinal needle, the rest of the spinal anesthetic procedure can be performed much more quickly. The mechanics of performing a safe epidural block (even when the initial dose is administered through the needle) include giving a test dose, waiting 3 to 4 min to observe the patient before further dosing, fractionating the local anesthetic dose over several minutes, and then threading the catheter. Administering a bolus of even a relatively nontoxic local anesthetic such as chloroprocaine is inappropriate, except in extreme emergencies. Furthermore, in our experience, 20 mL of chloroprocaine does not always produce an adequate block, necessitating further dosing and delay. We agree with Dr. Colclough that continuous epidural anesthesia is inherently more versatile than spinal anesthesia, but believe that the "one-shot" epidural technique he describes lacks versatility until the catheter has been tested and confirmed to be correctly sited. This would require injection of a second test dose via the catheter, causing additional delay. Perhaps the most compelling argument favoring spinal anesthesia is the decreased incidence of potential complications. When giving local anesthetics into the epidural space, drug may be injected into either the intravascular or intrathecal space with disastrous results. Even when correctly deposited in the epidural space, maldistribution of drug may leave some nerve roots unblocked, causing a failed block. In summary, we believe our data support our conclusions. The increasing use of spinal anesthesia for cesarean section in major obstetric centers throughout the world similarly reflects the experience that failure and complications occur less frequently than with epidural anesthesia. We encourage others to critically review their practice. We especially invite practitioners in nonteaching centers to conduct similar studies to see whether the trends we report hold true in the general community. Edward T. Riley, MD Sheila E. Cohen, MB, ChB Alex Macario, MD Emily F. Ratner, MD Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305-5117

We sought to identify factors that are associated with hypotension after the induction of spinal anesthesia (SpA) by using an anesthesia information management system. Hypotension was defined as a decrease of mean arterial blood pressure of more than 30% within a 10-min interval, and relevance was defined as a therapeutic intervention with fluids or pressors within 20 min. From January 1, 1997, to August 5, 2000, data sets from 3315 patients receiving SpA were recorded on-line by using the automatic anesthesia record keeping system NarkoData. Hypotension meeting the predefined criteria occurred in 166 (5.4%) patients. Twenty-nine patient-, surgery-, and anesthesia-related variables were studied by using univariate analysis for a possible association with the occurrence of hypotension after SpA. Logistic regression with a forward stepwise algorithm was performed to identify independent variables (P < 0.05). The discriminative power of the logistic regression model was checked with a receiver operating characteristic curve. Calibration was tested with the Hosmer-Lemeshow goodness-of-fit test. The univariate analysis identified the following variables to be associated with hypotension after SpA: age, weight, height, body mass index, amount of plain bupivacaine 0.5% used for SpA, amount of colloid infusion before puncture, chronic alcohol consumption, ASA physical status, history of hypertension, urgency of surgery, surgical department, sensory block height of anesthesia, and frequency of puncture. In the multivariate analysis, independent factors for relevant hypotension after SpA consisted of three patient-related variables ("chronic alcohol consumption," odds ratio [OR] = 3.05; "history of hypertension," OR = 2.21; and the metric variable "body mass index," OR = 1.08) and two anesthesia-related variables ("sensory block height," OR = 2.32; and "urgency of surgery," OR = 2.84). The area of 0.68 (95% confidence interval, 0.63-0.72) below the receiver operating characteristic curve was significantly greater than 0.5 (P < 0.01). The goodness-of-fit test showed a good calibration of the model (H = 4.3, df = 7, P = 0.7; C = 7.3, df = 8, P = 0.51). This study contributes to the identification of patients with a high risk for hypotension after SpA induction, with the risk increasing two- or threefold with each additional risk factor. By using automated data collection, 5 (chronic alcohol consumption, history of hypertension, body mass index, sensory block height, and urgency of surgery) of 29 variables could be detected as having an association with hypotension after spinal anesthesia induction. The knowledge of these risk factors should be useful in increasing vigilance in those patients most at risk for hypotension, in allowing a more timely therapeutic intervention, or even in suggesting the use of alternative methods of spinal anesthesia, such as titrated continuous or small-dose spinal anesthesia.

The pH test paper: a tool for distinguishing between the cerebrospinal fluid and saline

[Image: see text] Image: A. Johnson, Vivo Visuals Studio.

To compare local anesthetic wound infiltration with intraperitoneal instillation of local anesthetic for analgesia after cesarean section under spinal anesthesia. This study was conducted on 150 pregnant women undergoing elective cesarean section under spinal anesthesia. Spinal anesthesia was performed with 7mg isobaric bupivacaine and 15 μcg fentanyl. The patients were randomized into three groups of 50 patients each: Group local anesthetic wound infiltration (LWI): 20 ml local anesthetic solution (10ml 0.5% bupivacaine and 10ml 2% lidocaine mixture) was administered subcutaneous wound infiltration at the end of surgery prior to skin closure and 20 ml saline was instilled into the uterine peritoneal area before fascia closure. Group intraperitoneal local anesthetic (IPLA): 20 ml local anesthetic solution (10ml 0.5% bupivacaine and 10ml 2% lidocaine mixture) was instilled into the uterine peritoneal area and 20 ml saline was administered subcutaneous wound infiltration. Group Placebo: 20 ml saline was instilled into the uterine peritoneal area and 20 ml saline was administered local subcutaneous wound infiltration. Pain scores at rest and on movement, total fentanyl consumption at 24 h, maternal satisfaction, and the time to first analgesic request were recorded. No statistically significant difference was observed in the postoperative pain scores at rest at 2, 12, and 24 h (p=0.314, 0.343, and 0.735, respectively) and on movement at 12 and 24 h (p=0.318 and 0.642, respectively) between the groups. The pain scores on movement at 2 h were significantly lower in Group IPLA compared with Group Placebo (p=0.047). There were no significant differences between the groups in terms of total fentanyl consumption and the time to first analgesic request. The use of intraperitoneal instillation of bupivacaine and lidocaine reduces early the pain score on movement in women undergoing cesarean section under spinal anesthesia.

Effective plexus anaesthesia in a patient with Ehlers–Danlos syndrome type III

Battling Hypotension in Cesarean Section

Continuous Spinal Anesthesia with Invasive Hemodynamic Monitoring for Surgical Repair of the Hip in Two Patients with Severe Aortic Stenosis

Combined spinal-epidural anaesthesia (CSEA) using a needle-through-needle technique is currently widely used. However, successful epidural needle placement does not mean a successful spinal needle placement during CSEA. Whether ultrasound assistance could increase the first-pass success rate of spinal needle placement for CSEA remains unknown. The aim of this study was to investigate if ultrasound assistance could increase the first-pass success rate of spinal needle placement through the epidural needle during CSEA performed by experienced anaesthesiologists in patients undergoing caesarean section. A prospective, randomised, double-blind study. Single centre, Department of Anaesthesiology, Shengjing Hospital, China Medical University, China, from June 2019 to September 2019. A total of 185 patients (aged 24 years to 52 years, American Society of Anesthesiologists grade (ASA) II-III, 38 to 40 weeks gestation) scheduled to undergo elective caesarean section under CSEA were enrolled. The patients were randomised to either an ultrasound group (patients received a preprocedural ultrasound scan, and the puncture site was identified by ultrasound imaging) and a palpation group (patients received a sham procedural ultrasound scan, and the puncture site was identified by conventional palpation). The primary outcome measure was the first-pass success rate for spinal needle placement through the epidural needle. Secondary outcome measures were total duration of CSEA, time required for successful epidural needle and spinal needle placement, number of epidural needle redirections and complications. Preprocedural ultrasound imaging significantly increased the first-pass success rate of spinal needle placement through the epidural needle compared with conventional palpation (93.8 vs. 68.8%, P < 0.001). Preprocedural ultrasound imaging also decreased the total duration of CSEA (186.9 ± 37.1 vs. 213 ± 60.4 s, P = 0.0015) and the time required for successful spinal needle placement (78.3 ± 22.9 vs. 100.1 ± 53.7 s, P < 0.01) compared with conventional palpation. Fewer patients in the ultrasound group needed epidural needle redirections during the spinal needle placement procedure than in the palpation group (four patients vs. 20 patients, P < 0.01). For experienced anaesthesiologists, preprocedural ultrasound imaging significantly increased the first-pass success rate of spinal needle placement through the epidural needle for obstetric patients undergoing caesarean section under CSEA. chictr.org.cn, identifier: ChiCTR1900024132.

Anesthetic management of a parturient with olivopontocerebellar degeneration.

Sir, Spinal anaesthesia mandates adherence to strict asepsis to prevent potentially dreaded complications such as meningitis. Ampoule impurities can be a potential cause of breach in asepsis. Here, we report an incidence of macroscopic ampoule impurity while loading the local anaesthetic for subarachnoid block. Local anaesthetics used for spinal anaesthesia are usually available in a single use glass ampoule. Few properties that are responsible for its wide use are excellent chemical resistance, impermeability and ability to tolerate sterilisation process. Problems encountered due to the use of glass ampoules are micro particles contamination and occupational risk due to percutaneous injuries while trying to break open the ampoule. To prevent percutaneous injury, mechanisms such as one point cut (OPC) and ‘rupture disk’ have been developed. In the OPC system, a small incision is made in the neck or strangulation point of the ampoule, between the head of the ampoule and the body. A small dot placed a few millimetres above the incision indicates the correct orientation for snapping the ampoule open.[1] In the ‘rupture disk’ system, an area of fragility is caused at the strangulation point using a temper process that partially penetrates the glass causing an area of fragility or weak point. A band is then painted at the strangulation point, indicating its point of weakness[1] [Figure 1a].Figure 1: (a) ‘Rupture disk’ system and one point cut system. (b) Impurity detected in the local anaesthetic solutionIn our case, a fragment of paint from the band accidentally fell into the local anaesthetic solution, while trying to break open the ampoule [Figure 1b]. As the impurity was detected before loading the local anaesthetic solution, the ampoule was discarded and a fresh ampoule was used. Contamination of ampoule with micro particles has been a constant concern among the healthcare providers and has been reported for a long time.[2] In the incident that we report, a visible particle of paint has contaminated the local anaesthetic solution. This not only exposes the patient to the risk of infection and meningitis, but also to a risk of organic reaction due to the injected particle. Meningitis following subarachnoid block has been reported before.[34] Meningitis can occur either due to a breach in asepsis during the procedure or due to the presence of pre-existing bacteraemia in the patient at the time when spinal is performed.[5] Though aseptic causes are more likely, the occurrence of septic meningitis is not uncommon. Strong adherence to asepsis can prevent purely iatrogenic complications such as meningitis from developing. It is preferable to use OPC system as an aid to snap open the ampoule in drugs intended for spinal and epidural use. Even if drugs are loaded from ampoules that have ‘rupture disk’ system, we strongly recommend careful inspection of the drug solution before loading the drug. Pre-sterilising the package and providing sterile ampoules have also been recommended to prevent infection. In addition, prudent measures should be taken to make spinal and epidural drugs available in shatterproof and easily snappable ampoules. The manufacturers should also ensure that the paint used in ‘rupture disk’ ampoule does not get fragmented while snapping open the ampoule. Use of filters in needles and use of smaller gauge needles have also been advocated as measures to reduce loading of glass micro particles in syringes.[1] Use of pre-filled syringes can be the way forward to prevent contamination of drug as well as occupational hazards. To conclude, careful inspection for visible ampoule impurities and ensuring strict asepsis can prevent iatrogenic complications during spinal anaesthesia. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Permanent paraparesis and cauda equina syndrome after epidural blood patch for postdural puncture headache.

The incidence of spinal anaesthetic failure, in the absence of technical failure or clinician dose/judgement errors, is in the region of 2.7% – 3.9%. Although clusters of cases suggest defects...