Comparison of Fat-Free Mass and Ideal Body Weight Scalar for Anesthetic Induction Dose of Propofol in Patients with Morbid Obesity: A Double-Blind, Randomized Clinical Trial

Background

Obesity is a growing problem worldwide and can affect both the pharmacodynamics and pharmacokinetics of various drugs, including anesthetics, resulting in the under-or overdosing of certain drugs. There is no consensus on the ideal dosing regimen for obese populations.

Objectives

In this study, 2 weight-based dosing of propofol used for induction of anesthesia were compared in terms of the onset of action time, adequacy of anesthesia, and effects on hemodynamic indices (eg, heart rate [HR] and blood pressure).

Methods

In this randomized, double-blind clinical trial, 40 patients with morbid obesity (MO) scheduled for bariatric surgery with body mass index (BMI) > 35, age 18 - 59 years, American Society of Anesthesiologists physical status (ASA-PS) II and III were randomly divided into 2 groups, using block randomization method, to receive 2 mg/kg of propofol for induction of anesthesia based on either fat-free mass (FFM) group or ideal body weight (IBW) group. The primary outcome was the time duration to reach the bispectral index (BIS) ≤ 60. Time to the disappearance of eyelash reflex, signs of inadequate anesthesia (ie, BIS > 60, straining during intubation, or eye-opening), requirements for additional doses, and hemodynamic indices (including HR and mean arterial pressure [MAP]) were also compared.

Results

The mean time to reach BIS ≤ 60 was 134.1 s in the FFM group and 148.7 s in the IBW group. This difference was not statistically significant (P = 0.334). The time of disappearance of eyelash reflex was also not significantly different between the study groups (P = 0.814). However, 2 patients in the FFM group and 8 patients in the IBW group showed signs of inadequate anesthesia and required additional doses. This difference was statistically significant (P = 0.032). Hemodynamic variables, before and 2 min after propofol induction dose administration were comparable between the study groups (P = 0.520, P = 0.327, P = 0.847, P = 0.516 for pre-intervention MAP, post-intervention MAP, pre-intervention HR, and post-intervention HR, respectively).

Conclusions

Propofol dosing, based on FFM and IBW, for induction of anesthesia, provides comparable onset time of action and hemodynamic effects; however, in terms of the adequacy of anesthesia, the dosing based on FFM is more favorable compared to the dosing based on IBW.

Comparison of Pressure and Volume-Controlled Mechanical Ventilation in Laparoscopic Bariatric Surgery: A Randomized Crossover Trial

Background

The number of patients with obesity undergoing various surgeries is increasing annually, and ventilation problems are highly prevalent in these patients.

Objectives

We aimed to evaluate ventilation effectiveness with pressure-controlled (PC) and volume-controlled (VC) ventilation modes during laparoscopic bariatric surgery.

Methods

In this open-label randomized crossover clinical trial, 40 adult patients with morbid obesity candidates for laparoscopic bariatric surgery were assigned to VC-PC or PC-VC groups. Each patient received both ventilation modes sequentially for 15 min during laparoscopic surgery in a random sequence. Every 5 min, exhaled tidal volume, peak and mean airway pressure, oxygen saturation, heart rate, mean arterial pressure, and end-tidal CO₂ were recorded. Blood gas analysis was done at the end of 15 min. Dynamic compliance, PaO₂/FiO₂ ratio, P (A-a) O₂ gradient, respiratory dead space, and PaCO₂-ETCO₂ gradient were calculated according to the obtained results.

Results

The study included 40 patients with a mean age of 35.13 ± 9.06 years. There were no significant differences in peak and mean airway pressure, dynamic compliance, and hemodynamic parameters (P > 0.05). There was no significant difference between the two ventilation modes in pH, PaCO₂, PaO₂, PaO₂/FIO₂, dead space volume, and D (A-a) O₂ at different time intervals (P > 0.05).

Conclusions

If low tidal volumes are used during adult laparoscopic bariatric surgery, mechanical ventilation with PC mode is not superior to VC mode.

Effect of Different Loading Doses of Dexmedetomidine on Controlled Hypotension and the Incidence of Bradycardia During Rhinoplasty: A Clinical Trial

Controlled hypotension, with a mean arterial pressure (MAP) of 60 mmHg - 70 mmHg, provides a bloodless and visible surgical field during rhinoplasty. It has been shown that dexmedetomidine, an α2-adrenoreceptor agonist, is a suitable choice in this regard. One of the disadvantages of this drug is the possibility of severe bradycardia during infusion. Therefore, we compared lower intravenous (IV) loading doses to determine whether the hypotensive effect of the drug was preserved and the bradycardia incidence decreased. In this randomized, double-blinded clinical trial, 81 patients aged 18 to 50 years with the American Society of Anesthesiologists physical status (ASA-PS) class I and II, scheduled for rhinoplasty randomly received 1.0, 0.9, and 0.8 µg/kg (named as groups 1.0, 0.9, and 0.8, respectively) of IV dexmedetomidine before the induction of anesthesia followed by infusion (0.3 - 0.7 µg/kg/h) during operation. The patients' heart rate (HR), MAP, the requirements for nitroglycerin (NTG) and extra fentanyl, as well as the incidence of bradycardia, were recorded. Bleeding and visibility of the surgical field were scored by the surgeon using a 6-point visual scale. MAPs, HRs, and consumption of NTG and extra fentanyl were similar in the studied groups. The surgical field was more visible and bloodless in group 1.0 compared to group 0.8 (P < 0.001); the differences were not significant between groups 1.0 and 0.9 (P = 0.605). The incidence (P = 0.027) and the severity of bradycardia (P = 0.017) were higher in the groups with higher loading doses. We concluded that dexmedetomidine is an acceptable agent to provide controlled hypotension. A loading dose of 0.9 µg/kg, but not 0.8 µg/kg, provides similar surgical field conditions as the dose of 1 µg/kg. Furthermore, despite the decrease in the incidence of bradycardia, the hypotensive effect of the drug is preserved.

A clinical trial of volume- versus pressure-controlled intraoperative ventilation during laparoscopic bariatric surgeries

BACKGROUND

Intra-operative ventilation is often challenging in patients with morbid obesity undergoing bariatric surgery.

OBJECTIVES

To test the noninferiority of pressure-controlled ventilation (PCV) to volume-controlled ventilation (VCV) in respiratory mechanics.

SETTING

Bariatric Surgery Center, Iran.

METHODS

In a randomized open-labeled clinical trial, 66 individuals with morbid obesity undergoing laparoscopic bariatric surgeries underwent intraoperative ventilation with either PCV or VCV. The measurements taken were peak and mean airway pressures (H₂O), partial pressure of arterial oxygen (PaO₂), partial pressure of arterial carbon dioxide (PaCO₂) and end-tidal carbon dioxide (CO₂). We additionally collected pulse-oximetric oxygen saturation, inspiratory concentration of oxygen (FiO₂), and hemodynamic variables. Data were analyzed with repeated measures over the time of intubation, after peritoneal insufflation, and every 15 minutes, thereafter up to one hour.

RESULTS

PCV mode was successful to sustain adequate ventilation in 97% of the patients, which was similar to the 94% success rate of the VCV mode. Peak airway pressure increased 6 cmH₂O and end-tidal CO₂ rose by 5 mm Hg after abdominal insufflation in both groups (P = .850 and .376). Alveolar-arterial oxygen gradient similarly increased within 30 minutes after tracheal intubation both in PCV and VCV groups, with small trend of being higher in the VCV group. The ratio of dead space to tidal volumes (VD/VT) did not have a meaningful change (P = .724).

CONCLUSION

PCV was noninferior to VCV during laparoscopic bariatric surgery. Either mode of ventilation could be alternatively used during the anesthesia care of these patients.

Effect of General Versus Spinal Anesthesia on Postoperative Delirium and Early Cognitive Dysfunction in Elderly Patients

Background

Postoperative cognitive dysfunction (POCD) and delirium are common in the elderly patients, given the controversial results of previous studies about the impact of anesthesia type on the occurrence of these complications.

Objectives

This study was planned to compare the effects of general and spinal anesthesia on the prevalence of POCD and delirium.

Methods

A single-blind non-randomized clinical trial. Setting was in two academic hospitals. Ninety-four patients over 50 years old scheduled for hip fracture fixation. Patients were divided into two groups to receive either general (GA) or spinal (SA) anesthesia. Both Mini-Mental State examination (MMSE) and Wechsler tests were used before the operation and 3 times postoperatively to assess the cognitive function and detect early POCD. The DSM-IV criteria were also used for the diagnosis of delirium. The incidence of delirium and POCD and their precipitating factors were compared between the two groups.

Results

Ninety-four patients with a mean age of 67.12 years were studied. The overall prevalence of POCD and delirium was 17.02%; however, it was significantly higher in the GA group rather than the SA group, 29.7%, and 4.25%, respectively (P < 0.001). There was a significant relationship between age (P = 0.048), ASA class (P = 0.034), and educational level with the incidence of POCD, meaning that the probability of developing cognitive impairment decreases with patients' higher level of education and lower ASA-physical status. Also, the rate of POCD in men was significantly higher than in women (P = 0.026).

Conclusions

The finding of this study showed that, if there is no specific contraindication, neuraxial anesthesia may be preferred over general anesthesia in elderly patients.

The Effect of Intravesical Diluted Bupivacaine on Catheter-Related Bladder Discomfort in Young and Middle-Aged Male Patients During Postanaesthetic Recovery

Objective

Catheter-related bladder discomfort (CRBD) that manifests as agitation and bladder hyperactivity is a common problem in young male patients. Local anaesthetics are typically recommended for this problem. Hence, this study was conducted to determine the effect of intravesical diluted bupivacaine on CRBD in young male patients during postanaesthetic recovery.

Methods

This double-blinded randomised clinical trial included 68 consecutive patients, aged 20–60 years, who underwent urinary catheterisation during surgery and anaesthesia at a university hospital during 2017–2018. Patients were randomly assigned to receive either 50 ml of intravesical diluted (0.2%) bupivacaine (n=37) or normal saline (n=31). The incidence and severity of CRBD were then evaluated in PACU and compared between the two groups.

Results

In this study, 16.2% of patients in the bupivacaine group and 83.9% in the saline group had discomfort at arrival in the recovery room, exhibiting a significant intergroup difference (p=0.0001). Moreover, after 15–20 min, the incidence of CRBD was 16.2% and 90.3% in the bupivacaine and normal saline groups, respectively, which again demonstrated a significant statistical difference (p=0.0001). In addition, the severity of CRBD was lower in the bupivacaine group, during both periods (p=0.005). The saline group reported significantly higher use of pethidine and midazolam (p=0.005).

Conclusion

It may be concluded that intravesical diluted bupivacaine can significantly decrease the incidence and severity of CRBD in young male patients during recovery from anaesthesia. Therefore, the use of this method is highly recommended.

The effect of intraoperative lung protective ventilation vs conventional ventilation, on postoperative pulmonary complications after cardiopulmonary bypass

Introduction: This study aimed to evaluate the effects of high positive-end expiratory pressure (PEEP) and low tidal volume (TV) and recruitment maneuver, on postoperative pulmonary complications (PPCs) after coronary artery bypass grafting (CABG) surgery.

Methods: This study is a randomized double blind clinical trial on 64 patients who were undergoing CABG surgery, and were randomly divided into two groups of conventional ventilation (C-Vent) with TV of 9 mL/kg and PEEP=0 cm H2O, and lung protective ventilation (P-Vent), with 6 mL/kg TV and PEEP=10 cm H2O with recruitment maneuver every 30 minutes. Measures of PPCs and modified clinical pulmonary infection score (mCPIS), were assessed for the first 24 hours of postoperative time in order to evaluate the pulmonary complications.

Results: P-Vent with 31 patients and C-Vent with 30 patients, participated in the stage of data analysis. Demographic, and preoperative laboratory results showed no significant difference between two groups. During surgery, cardiovascular complications were higher in P-Vent group (P = 0.61) but pulmonary complications were higher in C-Vent group (P = 0.26). Extubation time was not significantly different between two groups, and also components of arterial blood gases (ABG) of 24 hours after surgery showed no significant difference between the two groups. Pathologic changes in the chest X-ray (CXR) of 24 hours after surgery, were lower in P-Vent group, but the difference was not significant (P = 0.22). The PPC criteria was less positive in P-Vent (2 patients) vs 9 patients in C-Vent group (P = 0.02) and mCPIS score was significantly lower in P-Vent group (1.2 ± 1.4) than C-Vent group (2 ± 1.6) (P = 0.048).

Conclusion: Lung protective strategy during and after cardiac surgery, reduces the postoperative mCPIS in patients undergoing open heart surgery for CABG.

Comparing the Effect of Preoperative Administration of Melatonin and Passiflora incarnata on Postoperative Cognitive Disorders in Adult Patients Undergoing Elective Surgery

Background

Anxiety is a preoperative complication, which most patients encounter. The use of a premedication to reduce preoperative anxiety with minimal cognitive impairment is crucial.

Objectives

This study was conducted to compare the sedative effect of preoperative melatonin and Passiflora incarnata in patients undergoing elective surgery regarding their potential for postoperative cognitive disorders.

Methods

In this clinical trial, 52 patients American society of anesthesiologists grade (ASA) I and II of both genders were selected to receive either Passiflora incarnata (1000 mg nature made) (n = 26) or melatonin (6 mg) (n = 26) as premedication one hour before surgery. Post-operative pain was evaluated using the visual analogue scale (VAS). Patient’s anxiety and cognitive dysfunction was evaluated with the Ramsey score and the digital symbol substitution test (DSST), respectively. All tests were carried out and evaluated at arrival in the operating room, before induction and before discharge from the post anesthesia care unit (PACU).

Results

There were no statistically differences between groups in VAS (P > 0.05). However, the mean score of pain was higher in the melatonin group compared to the Pssiflora incarnata group when discharged from the PACU (27.63 vs. 25.37). The anxiety scores were statistically significant in both drugs (P = 0.001), however higher sedation scores was caused by premedication with melatonin (P = 0.003 vs. 0.008). Regarding the DSST, there was a significant difference between the two groups one hour before the surgery (P = 0.04) and at the time of discharge from the PACU (P = 0.007). When evaluating each group, the Passiflora incarnata group revealed a significant difference (P = 0.003).

Conclusions

Our findings show that premedication with Passiflora incarnata reduces anxiety as well as Melatonin. However, Melatonin causes less cognitive impairment compared to Passiflora incarnata.

Comparing GlideScope Video Laryngoscope and Macintosh Laryngoscope Regarding Hemodynamic Responses During Orotracheal Intubation: A Randomized Controlled Trial

BACKGROUND

To determine if the GlideScope® videolaryngoscope (GVL) could attenuate the hemodynamic responses to orotracheal intubation compared with conventional Macintosh laryngoscope.

OBJECTIVES

The aim of this relatively large randomized trial was to compare the hemodynamic stress responses during laryngoscopy and tracheal intubation using GVL versus MCL amongst healthy adult individuals receiving general anesthesia for elective surgeries.

PATIENTS AND METHODS

Ninety five healthy adult patients with American Society of Anesthesiologists physical status class I or II that were scheduled for elective surgery under general anesthesia were randomly allocated to either Macintosh or GlideScope arms. All patients received a standardized protocol of general anesthesia. Hemodynamic changes associated with intubation were recorded before and at 1, 3 and 5 minutes after the intubation. The time taken to perform endotracheal intubation was also noted in both groups.

RESULTS

Immediately before laryngoscopy (pre-laryngoscopy), the values of all hemodynamic variables did not differ significantly between the two groups (All P values > 0.05). Blood pressures and HR values changed significantly over time within the groups. Time to intubation was significantly longer in the GlideScope (15.9 ± 6.7 seconds) than in the Macintosh group (7.8 ± 3.7 sec) (P< 0.001). However, there were no significant differences between the two groups in hemodynamic responses at all time points.

CONCLUSIONS

The longer intubation time using GVL suggests that the benefit of GVL could become apparent if the time taken for orotracheal intubation could be decreased in GlideScope group.

Anesthetic management for lower limb fracture in severe aortic valve stenosis and fat embolism: a case report and review of literature

Introduction:

Anesthesia in severe aortic stenosis, which describes a valve surface area less than 1 cm², can result in rapid clinical deterioration and patient mortality. These patients may require treatment for aortic stenosis before any surgical intervention. In suitable patients percutaneous balloon aortic valvutomy appears to carry lower risk, but in emergency situations, it is important to determine which kind of anesthesia technique has the lowest risk for these patients, without any cardiac intervention.

Case Presentation:

In this case report, we present a patient who had tibia and fibula fractures and a symptomatic severe critical aortic stenosis which was diagnosed during a preoperative visit. The patient had exertional dyspnea, palpitations and fainting history, but he had not received any medical therapy before the present admission. During hospitalization and preoperative evaluation, a fat embolism occurred and the patient was admitted to the intensive care unit. Immediately after his recovery, we successfully managed the tibia and fibula fracture fixation without any cardiac intervention.

Conclusions:

Our anesthesia method was sciatic and femoral nerve block under double ultrasonic and nerve stimulator guidance.

Intravenous acetaminophen is superior to ketamine for postoperative pain after abdominal hysterectomy: results of a prospective, randomized, double-blind, multicenter clinical trial

BACKGROUND

In recent years, intravenously (IV) administered acetaminophen has become one of the most common perioperative analgesics. Despite its now-routine use, IV acetaminophen's analgesic comparative efficacy has never been compared with that of ketamine, a decades-old analgesic familiar to obstetricians, gynecologists, and anesthesiologists alike. This doubleblind clinical trial aimed to evaluate the analgesic effects of ketamine and IV acetaminophen on postoperative pain after abdominal hysterectomy.

METHODS

Eighty women aged 25-70 years old and meeting inclusion and exclusion criteria were randomly allocated into two groups of 40 to receive either IV acetaminophen or ketamine intraoperatively. Postoperatively, each patient had patient-controlled analgesia. Pain and sedation (Ramsay Sedation Scale) were documented based on the visual analog scale in the recovery room and at 4 hours, 6 hours, 12 hours, and 24 hours after the surgery. Hemodynamic changes, adverse medication effects, and the need for breakthrough meperidine were also recorded for both groups. Data were analyzed by repeated-measures analysis of variance.

RESULTS

Visual analog scale scores were significantly lower in the IV acetaminophen group at each time point (P<0.05), and this group required significantly fewer doses of breakthrough analgesics compared with the ketamine group (P=0.039). The two groups had no significant differences in terms of adverse effects.

CONCLUSION

Compared with ketamine, IV acetaminophen significantly improved postoperative pain after abdominal hysterectomy.

Adjuvant hyaluronidase to epidural steroid improves the quality of analgesia in failed back surgery syndrome: a prospective randomized clinical trial

BACKGROUND

Management of low back pain after spinal surgeries is one of the most challenging problems in pain medicine. Transforaminal lumbar epidural steroid injection has been used with inconsistent response. Most patients require multiple and frequent injections due to high recurrence of back pain.

OBJECTIVE

To find out whether the addition of hyaluronidase to the epidural injectate affects the quality and duration of analgesia in patients with low back pain secondary to failed back surgery syndrome.

STUDY DESIGN

Prospective randomized trial.

METHODS

The study was registered in the Government Clinical Trial registry and the protocol was reviewed and approved by the institutional review board. After obtaining an informed consent, 25 patients with low back pain due to failed back syndrome were randomly assigned to receive a transforaminal epidural injection of hyaluronidase 1500 IU (HYL) or normal saline (NSL) to a mixture of bupivacaine 0.5% (1 mL) and triamcinolone 40 mg (1 mL) in a double-blind fashion. An interventional pain specialist using fluoroscopic guidance performed all epidural injections. The patients received a comprehensive neurological examination by a non-interventional pain specialist who was blinded to the treatment during their follow-up visits, scheduled one, 2, and 4 weeks after the intervention. Numerical pain scores, analgesic requirement, and satisfaction scores were recorded during every visit.

RESULTS

There was no difference in demographic data between the 2 groups. Pain scores and total analgesic requirement were significantly lower in the HYL group at 2 and 4 weeks after blockade (P < 0.01). Patient satisfaction was higher in the HYL group.

LIMITATIONS

The study was limited by a relatively small sample size.

CONCLUSION

We conclude that adding hyaluronidase to the epidural injectate was effective in the management of chronic low back pain in patients with failed back surgery syndrome demonstrated over a period of 4 weeks.