Caroline B. Palmer: Pioneer Physician Anesthetist and First Chair of Anesthesia at Stanford.

Caroline B. Palmer was appointed as Chief of Anesthesia at Cooper Medical College (soon renamed as Stanford Medical School) in 1909. For the next 28 years, she was an innovative leader, a clinical researcher, and a strong advocate for recognition of anesthesiology as a medical specialty. To honor her accomplishments, the operating room suite in the new Stanford Hospital will be named after this pioneering woman anesthesiologist.

The significance of widely split P waves: a case report.

BACKGROUND: P wave morphology on electrocardiogram is often overlooked but indicates abnormal cardiac conduction from various etiologies. Split P waves on electrocardiogram have been reported previously but not in a perioperative setting. CASE PRESENTATION: A 69-year-old Caucasian male patient with widely split P waves on his preoperative electrocardiogram was scheduled for a reimplantation right total hip replacement under a combined spinal-general anesthetic technique. The patient was evaluated prior to surgery by a cardiologist and the preoperative anesthesia clinic without any comment on the abnormal P wave morphology on electrocardiogram. The patient was cleared to proceed with anesthesia and surgery. Following induction of general anesthesia, his cardiac rhythm changed to a Mobitz type II pattern. The surgical procedure was cancelled, and a permanent cardiac pacemaker was inserted. CONCLUSIONS: Anesthesiologists should be aware that the presence of widely split P waves on electrocardiogram indicates the presence of atrial conduction abnormalities, likely from an ischemic or infiltrative process that can lead to more serious cardiac arrhythmias. P wave morphology should be observed and noted during the perioperative period for all patients.

Lean body weight scalar for the anesthetic induction dose of propofol in morbidly obese subjects.

BACKGROUND: The unique anesthetic risks associated with the morbidly obese (MO) population have been documented. Pharmacologic management of these patients may be altered because of the physiologic and anthropometric changes associated with obesity. Unfortunately, studies examining the effects of extreme obesity on the pharmacology of anesthetics have been sparse. Although propofol is the induction drug most frequently used in these patients, the appropriate induction dosing scalar for propofol remains controversial in MO subjects. Therefore, we compared different weight-based scalars for dosing propofol for anesthetic induction in MO subjects. METHODS: Sixty MO subjects (body mass index ≥40 kg/m(2)) were randomized to receive a propofol infusion (100 mg · kg(-1) · h(-1)) for induction of anesthesia based on total body weight (TBW) or lean body weight (LBW). Thirty control subjects (body mass index ≤25 kg/m(2)) received a propofol infusion (100 mg · kg(-1) · h(-1)) based on TBW. Syringe drop was used as the marker for loss of consciousness (LOC), at which point the propofol infusion was stopped. The propofol dose required for syringe drop and time to LOC were recorded. RESULTS: Total propofol dose (mg/kg) required for syringe drop and time to LOC were similar between control subjects and MO subjects given propofol based on LBW. MO subjects receiving a propofol infusion based on TBW had a significantly larger propofol dose and significantly shorter time to LOC. There was a strong relationship between LBW and total propofol dose received in all 3 groups. CONCLUSION: LBW is a more appropriate weight-based scalar for propofol infusion for induction of general anesthesia in MO subjects.

Comparison of procedural times for ultrasound-guided perineural catheter insertion in obese and nonobese patients.

OBJECTIVES: Perineural catheter insertion with ultrasound guidance alone has been described, but it remains unknown whether this new technique results in the same procedural time and success rate for obese and nonobese patients. We therefore tested the hypothesis that obese patients require more time for perineural catheter insertion compared to nonobese patients despite using ultrasound. METHODS: Data from 5 previously published randomized clinical trials comparing ultrasound- and stimulation-guided perineural catheter insertion techniques were reviewed, and patients who received ultrasound-guided catheters were divided into 2 groups: obese (body mass index ≥30 kg/m(2)) and nonobese (body mass index <30 kg/m(2)). A standardized ultrasound-guided nonstimulating catheter technique was used with mepivacaine, 1.5% (40 mL), as the initial bolus via the placement needle for the primary surgical nerve block. The primary outcome was the procedural time for perineural catheter insertion. Secondary outcomes included block efficacy, procedure-related pain, fluid leakage, vascular puncture, and catheter dislodgment. RESULTS: A sample of 120 patients was identified: 51 obese and 69 nonobese. All obese patients had successful catheter placement compared to 68 of 69 (98%) nonobese patients (P = .388). The time for perineural catheter insertion [median (10th-90th percentiles)] was 7 (4-12) minutes for obese patients versus 7 (4-15) minutes for nonobese patients (P = .732). There were no statistically significant differences in other secondary outcomes. CONCLUSIONS: On the basis of this retrospective analysis, perineural catheter insertion is not prolonged in obese patients compared to nonobese patients when an ultrasound-guided technique is used. However, these results are only suggestive and require confirmation through prospective study.

Regional anesthesia and obesity.

PURPOSE OF REVIEW: Worldwide, the number of overweight and obese patients has increased dramatically. As a result, anesthesiologists routinely encounter obese patients daily in their clinical practice. The use of regional anesthesia is becoming increasingly popular for these patients. When appropriate, a regional anesthetic offers advantages and should be considered in the anesthetic management plan of obese patients. The following is a review of regional anesthesia in obesity, with special consideration of the unique challenges presented to the anesthesiologist by the obese patient. RECENT FINDINGS: Recent studies report difficulty in achieving peripheral and neuraxial blockade in obese patients. For example, there is an increased incidence of failed blocks in obese patients compared with similar, normal weight patients. Despite difficulties, regional anesthesia can be used successfully in obese patients, even in the ambulatory surgery setting. SUMMARY: Successful peripheral and neuraxial blockade in obese patients requires an anesthesiologist experienced in regional techniques, and one with the knowledge of the physiologic and pharmacologic differences that are unique to the obese patient.

Intraoperative contralateral tension pneumothorax during pneumonectomy.

Unrecognized tension pneumothorax can have catastrophic consequences. We report a case of a patient who developed a contralateral tension pneumothorax during thoracotomy without the classic signs of marked hypoxemia and hemodynamic instability. A tension pneumothorax should be considered in any patient who develops high peak inspiratory pressures during one-lung ventilation with an open chest, even in the absence of the classic signs of hypoxemia and hypotension.

Recent advances in anesthesia of the obese patient.

The anesthetic management of an obese patient can be challenging because of the altered anatomy and physiology associated with obesity. In this article, I review the recent medical literature and highlight some of the controversies in the airway management and drug dosing of morbidly obese patients.

Regional anesthesia and obesity.

The potential advantages of regional anesthesia include minimal airway intervention, less cardiopulmonary depression, excellent postoperative analgesia, less postoperative nausea and vomiting, and shorter recovery room and hospital stays. These concerns are particularly important for the obese surgical patient. This review discusses the application of regional anesthetic techniques in obesity. Further clinical studies are needed to fill the knowledge gap about regional anesthesia and outcome in obese and morbidly obese patients.

Isolation of the right upper-lobe with a left-sided double-lumen tube after left-pneumonectomy.

A patient with a prior left pneumonectomy required surgical drainage of a right upper lobe aspergilloma. A left double-lumen endobronchial tube was placed in the right bronchus intermedius, isolating the right upper lobe while allowing ventilation of the right middle and lower lobes.

Capnoperitoneum During Peroral Endoscopic Myotomy-Recognition and Management: A Case Report.

Peroral endoscopic myotomy (POEM) is a minimally invasive procedure for treating esophageal achalasia. During POEM, carbon dioxide is insufflated under pressure into the esophagus and stomach, which can cause clinically significant capnoperitoneum, capnomediastinum, or capnothorax. We present a case in which gas accumulation in the abdomen during POEM had adverse effects on ventilation. Once the cause was recognized, needle decompression of the abdomen led to immediate improvement in ventilation.

Estimating blood volume in obese and morbidly obese patients.

Preoperative assessment of blood volume (BV) is important for patients undergoing surgery. The mean value for indexed blood volume ((In)BV) in normal weight adults is 70 mL/kg. Since (In)BV decreases in a non-linear manner with increasing weight, this value cannot be used for obese and morbidly obese patients. We present an equation that allows estimation of (In)BV over the entire range of body weights.

Anesthetic management of morbidly obese and super-morbidly obese patients undergoing bariatric operations: hospital course and outcomes.

BACKGROUND: Although the implications for the anesthetic and perioperative care of severely obese patients undergoing weight loss operations are considerable, current anesthetic management of super-obese (SO) patients (BMI > or =50 kg/m(2)), including super-super-obese (BMI > or =60) derives from experience with morbidly obese (MO) patients (BMI 40-49.9 kg/m(2)). We compared anesthetic and perioperative data of SO patients and MO patients undergoing weight loss operations to evaluate if anesthetic management influenced outcome. METHODS: A retrospective analysis was performed on data from 150 consecutive patients (119 MO, 31 SO) undergoing bariatric surgery between May 2000 and March 2005. Data analyzed included preoperative anesthetic assessment, anesthetic management, postoperative care, and intra- or postoperative complications. RESULTS: There were no differences in anesthetic management or in postoperative course or outcome between MO and SO patients. Intraoperative surgical complications occurred in 26% (n=8) in the SO group and 14% (n=15) in the MO group (P<0.01). CONCLUSIONS: No differences in outcome occurred between MO and SO patients undergoing bariatric operations under similar anesthetic management. Anesthesia for weight loss surgery can be safely performed on SO patients with the understanding that these patients are not at risk per se due to their higher BMI. The degree of obesity influenced only the incidence of intraoperative surgical complications.

Intra-operative fluid volume influences postoperative nausea and vomiting after laparoscopic gastric bypass surgery.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (RYGBP) is a commonly performed operation for morbid obesity. A significant number of patients experience postoperative nausea and vomiting (PONV) following this procedure. The aim of this study was to determine the effect, if any, of intra-operative fluid replacement on PONV. METHODS: Patients who underwent laparoscopic (RYGBP) for morbid obesity during a 12-month period were included in this retrospective analysis. Demographic data including age, gender, and body mass index (BMI) were collected. Perioperative data also included total volume of intra-operative fluids administered, rate of administration, urine output, length of surgery, and incidence of PONV as determined by nursing or anesthesia records in the postanesthesia care unit (PACU). Data were analyzed by t-test. RESULTS: The table below depicts demographic and perioperative data, comparing patients who experienced PONV (n=125) in the PACU with those who did not (n=55). Values are mean +/- standard deviation. CONCLUSIONS: PONV is a common complication after laparoscopic RYGB. Patient who did not experience PONV received a larger volume of intravenous fluid at a faster rate than similar patients who complained of PONV.