Waleed Riad

Selection of obese patients undergoing ambulatory surgery: A systematic review of the literature

BACKGROUND: The incidence of obesity has increased over the past 2 decades. In recent years, several studies have assessed perioperative outcomes in obese patients undergoing ambulatory surgery. However, this evidence has not been reviewed and evaluated systematically. METHODS: We conducted a systematic review of studies published between 1948 and May 2012, assessing perioperative outcome in adult obese patients undergoing ambulatory surgery. All studies were eligible for inclusion if they reported perioperative complications including unplanned hospital admission and readmission. RESULTS: A literature search revealed 23 studies (13 prospective and 10 retrospective), and 1 systematic review assessing laparoscopic bariatric surgery. A total of 106,119 patients were included in the analysis with 62,476 patients included in the prospective trials and 43,643 patients included in the retrospective trials (not including the systematic review of laparoscopic bariatric surgery). Of these, 39,548 patients underwent bariatric surgery. The super obese (body mass index [BMI] >50 kg/m2) appear to be at higher risk of complications. Patients undergoing nonbariatric surgery had a lower degree of obesity (BMI approximately 30 kg/m2). Patients undergoing bariatric surgery were morbidly obese (BMI >40 kg/m2), which is associated with a higher comorbidity burden. However, the lack of increase in unanticipated admission rate in this patient population may be related to thorough preoperative assessment and avoidance of patients with comorbid conditions. DISCUSSION: The literature lacks adequate information to make strong recommendations regarding appropriate selection of the obese patients scheduled for ambulatory surgery. The literature does indicate that the super obese (BMI >50 kg/ m2) do present an increased risk for perioperative complications, while patient with lower BMIs do not seem to present any increased risk as long as any comorbidities are minimal or optimized before surgery. This review also identifies knowledge gaps and recommends future research required to guide optimal selection of obese patients scheduled for ambulatory surgery.

Quadratus Lumborum Block Versus Transversus Abdominis Plane Block for Postoperative Pain After Cesarean Delivery: A Randomized Controlled Trial.

Background and Objectives Effective postoperative analgesia after cesarean delivery enhances early recovery, ambulation, and breastfeeding. In a previous study, we established the effectiveness of the quadratus lumborum block in providing pain relief after cesarean delivery compared with patient-controlled analgesia (morphine). In the current study, we hypothesized that this method would be equal to or better than the transversus abdominis plane block with regard to pain relief and its duration of action after cesarean delivery. Methods Between April 2015 and August 2015, we randomized 76 patients scheduled for elective cesarean delivery under spinal anesthesia to receive the quadratus lumborum block or the transversus abdominis plane block for postoperative pain relief. This trial was registered prospectively (NCT 024489851). Results Patients in the quadratus lumborum block group used significantly less morphine than the transversus abdominis plane block group (P < 0.05) at 12, 24, and 48 hours but not at 4 and 6 hours after cesarean delivery. This group also had significantly fewer morphine demands than the control group (P < 0.05) at 6, 12, 24, and 48 hours after cesarean delivery. No significant differences in visual analog scale results were shown between the 2 groups at rest or with movement. Calculated total pain relief at rest and with movement were similar (P < 0.001) in both groups. Conclusions The quadratus lumborum block was more effective in reducing morphine consumption and demands than transversus abdominis plane blocks after cesarean section. This effect was observed up to 48 hours postoperatively.

Single Injection Peribulbar Anesthesia with a Short Needle Combined with Digital Compression

BACKGROUND: We compare the efficacy of using a 15 mm to the standard 25 mm needle for performing peribulbar blockade. METHODS: Blocks were performed on 150 patients using 15 or 25 mm needle length. Digital compression was applied by the thumb and index finger around the needle hub during injection with 15 mm needle. Anesthetic was injected until lid fullness was noted. Inadequate block was augmented. RESULTS: No significant differences were noted between groups with respect to local anesthetic volume, supplementation, and akinesia. CONCLUSION: Peribulbar blockade performed with a 15 mm needle with digital pressure is comparable to blockade using a 25 mm needle.

The effect of haemodilution with 6% hydroxyethyl starch (130/0.4) on haemostasis in pregnancy: an in-vitro assessment using thromboelastometry

Editor, Hydroxyethyl starch (HES) preparations are more effective than lactated Ringer’s solution in maintaining blood volume after rapid blood loss, but their use is limited by concerns over their effect on haemostasis. HES causes a reduction in circulating factor VIII and von Willebrand factor (VWF) that is not explained by the effect of dilution alone, and it also inhibits platelet function and fibrin polymerization. Low or medium molecular weight HES with low substitution seems to have a less negative effect on coagulation than high molecular weight preparations with high substitution. Late pregnancy is characterized by increased blood coagulability; this is due to increased fibrinogen and other coagulation factor levels and a reduction in the levels of natural inhibitors of coagulation such as protein C and S.

Comparison of levobupivacaine 0.5% or bupivacaine 0.5% both in a mixture with lidocaine 2% for superficial extraconal blockade

Purpose: To evaluate the quality and efficacy of Peribulbar blockade for superficial extraconal anesthesia with levobupivacaine 0.5% versus bupivacaine 0.5%, both combined with lidocaine 2% for patients undergoing phacoemulsification. Materials and Methods: In this prospective, double blind study, 150 patients were randomly divided into two groups: group-1 received a Peribulbar block (PB) with a mixture of evobupivacaine 0.5% and lidocaine 2% while group-2 received a PB with a mixture of bupivacaine 0.5% and lidocaine 2%. The block was performed by insertion of a short needle (15 mm) in infra-temporal space just above inferior orbital notch. An initial volume of 6 9 ml of either mixture was injected until total upper eyelid drop. Akinesia score was assessed at 2, 5, and 10 min after the block. The degree of pain was assessed by a verbal rating scale immediately after block, at the end of surgery and 4 h postoperatively. The patients and surgeons were asked to rate their satisfaction level of the quality of block postoperatively. Data were analyzed with the unpaired, two-tailed t-test and the Chi-square test as appropriate. P < 0.05 was considered statistically significant. Results: There were no significant differences between groups with respect to the akinesia score (P = 0.2) at 2, 5, and 10 min, the number of supplementary injections (P = 0.84) and initial and total required volume of local anesthetics (P = 0.80 and 0.81, respectively). There was no significant difference between the groups regarding surgeon and patient satisfaction (P = 0.53 and P = 0.74, respectively). Similarly the verbal rating scales assessed at three different occasions were not significantly different between the groups (P > 0.05 all cases). The need for additional intra-operative topical anesthetic was also similar between the groups. (P = 0.69). Conclusions: Superficial extra-conal block with a mixture of levobupivicaine 0.5% and lidocaine 2% or bupivicaine 0.5% and lidocaine 2% provides similar block quality and efficacy.

Continent-wide anaesthesia guideline: a step towards safer practice.

De Hert S, Imberger G, Carlisle J, et al. Preoperative latest evidence-based medical knowledge to simplify and/or eliminate unnecessary steps. Physicians are expected to be familiar with clinical guidelines, but should note that they are advisory in nature and are there to help with safer decision making, something which might vary according to the patient’s condition and the available resources. Practice guidelines should be revised periodically to accommodate newly published data. In 2007, the Anaesthesiology Board of European Union of Medical Specialists published guidelines for the safety and quality of anaesthesia. A more recent milestone was the Helsinki Declaration on Patient Safety in Anaesthesiology published in June 2010. This represented a European consensus on measures to improve patient care and it set out a framework for good practice. In order to constrain costs and standardise practice across Europe, the European Society of Anaesthesiologists (ESA) took a giant step forward by committing to the development of evidenced-based clinical guidelines and recommendations. In this issue, the unique specific task force, led by Professor Stefan De Hert, has published an outstanding guideline for the preoperative evaluation of adult patients undergoing elective non-cardiac surgery. Their recommendations are very comprehensive. They cover a wide range of topics that include cardiovascular disease, respiratory disease, obstructive sleep apnoea (OSA), renal disease, diabetes, obesity, coagulation disorders, anaemia, the elderly patient, alcohol addiction and allergy. They also cover concurrent medication, and preoperative testing. In addition, there is a very useful section on airway evaluation.

Should all Morbidly Obese Patients be Evaluated for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by repetitive episodes of apnea and hypopnea during sleep. There is a strong positive correlation between morbid obesity (MO) and OSA, with a prevalence of OSA in MO patients believed to be between 70 and 95%. It has been estimated that a body mass index (BMI) > 28 kg m−2 increases the possibility of moderate-to-severe OSA by fivefold. The gold standard for diagnosis of OSA is by polysomnography (PSG). However, it is a lengthy procedure and requires significant resources. In order to constrain cost and decrease the waiting time for diagnosis several portable sleep monitoring devices have been used successfully. Alternatively, there are screening questionnaires that are designed to classify patients based on history and physical examination in order to identify patients who need a formal sleep study. As each tool has its own limitation, this chapter will discuss in details all the possible options and the best way to accurately diagnose MO patients.

Ocular phenylephrine 2.5% continues to be dangerous

Phenylephrine 10% is used for pupillary dilatation and capillary decongestion. It had been advised to use a 2.5% concentration instead of 10% to guard against systemic reactions. Here, a case of severe systemic manifestation following conjuctival application of 2.5% phenylephrine is described. A healthy adult was admitted for pterygium excision under ophthalmic blockade. Vital signs remained normal until a sponge soaked with phenylephrine 2.5% was applied over the excised pterygium to control bleeding. The patient developed bradycardia (heart rate of 30 bpm) and hypotension (pressure 80/40 mmHg), so intravenous atropine was given. This was followed by tachycardia (heart rate of 150 bpm) and hypertension (pressure 240/130 mmHg) and ECG showed ischaemic changes. Treatment included propofol, labetalol, frusamide, morphine and dexamethasone. The next day, a 12-lead ECG showed no ischaemic changes and the myocardial infarction screen was negative. Fundus examination showed no sign of papilloedema. This report emphasises that phenylephrine 2.5% is still dangerous, with unpredictable response.

In reply: Optimal propofol induction dose in morbidly obese patients: bispectral index guidance is not the answer

To the Editor, We thank Dr. Chiravuri and colleagues for their valuable comments on our randomized controlled trial. Dr. Chiravuri indicated that the bispectral index (BIS) is a brain-state monitor and was not designed to guide anesthetic induction. However, there is precedent in the literature that a BIS target of 50 may be used as an end point of induction. Because of the lack of data in the literature, our objective was to determine if the BIS monitor is an appropriate approach to guiding induction of anesthesia in morbidly obese (MO) patients. In their letter, Chiravuri et al. stated that the two groups were randomized as follows: ‘‘Propofol dosing based on: 1) the calculated lean body weight (LBW group), or 2) propofol infusion 100 mg kg hr to an initial targeted BIS of 50 (BIS group).’’ We want to clarify that both the LBW and the BIS groups received the same propofol infusion of 100 mg kg hr based on the LBW. The LBW was calculated based on the Janmahasatian equation. The LBW group received this infusion until a predetermined dose of 2.6 mg kg LBW was reached, whereas the BIS group received the infusion until a BIS target of 50 was reached. As explained in our article, the BIS target of 50 is based on studies by Gürses et al. and Arya et al., which compared the clinical end point of the loss of verbal response with BIS for induction with propofol, using a mean (standard deviation) BIS of 48 (2) as an end point for induction. The 2.6 mg kg LBW dose of propofol was based on the results obtained in the study conducted by Ingrande et al., which showed that the LBW scalar is appropriate for inducing MO patients with propofol. This initial dosing was defined as a target point. However, the infusion was continued until the Observer’s Assessment of Alertness/Sedation Scale was 0, which was taken as an end point for induction. The doses at the target points and infusion end points are reported based on both total body weight and LBW for both groups in Table 3 of our article. We emphasize that both groups received the infusion in the same manner, but the targets were different – i.e., LBW-based dosing vs BIS-based dosing. We agree that MO patients should be included during the drug-development stage because there is currently no consensus on dosing of anesthetic agents in MO patients due to the paucity of data. This is particularly important given the obesity epidemic. Our study – one of the very few studies examining the application of BIS for anesthetic induction in MO patients – provides promise that BIS may be useful in this regard.

Preoperative screening for obstructive sleep apnea in morbidly obese patients.

In the western world, obesity is considered a key health problem. It has been estimated that more than two thirds of North Americans are overweight or obese and almost 34% of adults and 15% to 20% of children and adolescents of the US population are obese. Obesity has long been recognized as a predecessor of morbidity and premature mortality. It is frequently associated with a higher incidence of hypertension, lethal cardiac dysrhythmia, ischemic heart disease, and premature coronary death. Other related medical problems include hyperglycemia, diabetes mellitus, dyslipidemia, gall bladder disease, nonalcoholic fatty liver disease, stroke, degenerative joint disease, and obstructive sleep apnea (OSA). In addition to a poor quality of life; obesity is associated with hormonal changes that can lead to an increased likelihood of malignant tumors. Uterine and breast tumors have been documented in obese females. Similarly, a higher incidence of renal and esophageal carcinoma is reported in obese males compared to the normal weight population. Data showed that obesity was responsible for 365,000 preventable deaths in 2000. Given the increasing risk with comorbidity, the standard definition of morbid obesity was modified to incorporate patients of body mass index (BMI)Z35 kg/m with concomitant obesity-related disease. One of the major health care expenditures in the coming 2 decades will be the treatment of metabolic disease associated with obesity. With the increased life expectancy and