Anesthetic Management of Patients with Obesity with and Without Sleep Apnea

Association of obesity with inflammation and pain after total hip arthroplasty

BACKGROUND

The prevalence of obesity is increasing, and obesity often leads to degenerative joint disease requiring total hip arthroplasty (THA). Obesity is a proinflammatory state associated with an increase in chronic, low-grade inflammatory response. As such, it may augment the postoperative inflammatory response, which has been associated with postoperative pain and complications.

QUESTIONS/PURPOSES

We determined whether severity of obesity was associated with (1) severity of inflammatory response, as measured by the in vivo circulating levels of cytokines and ex vivo functional reactivity of mononuclear blood cells, and (2) severity of pain, as measured by verbal pain scores and analgesic consumption, in the first 24 hours after THA.

METHODS

We studied 60 patients (20 normal weight, 20 overweight, 20 obese) undergoing elective primary unilateral THA in this prospective cross-sectional study. Blood samples were collected for C-reactive protein and cytokine levels, including IL-1β, IL-2, IL-6, IL-8, and tumor necrosis factor α (TNF-α), from patients before and 24 hours after surgery. Cytokine response of whole blood was evaluated ex vivo with or without two standard activators, phorbol-12-myristate-13-acetate and lipopolysaccharide, using standardized blood sample from patients at 24 hours. These standard immune activators are implicated in the inflammatory response to gram-negative infection, translocation of microbial products, pathophysiology of septic shock syndrome in human, and tumor promotion. Pain response was gauged using verbal pain scores (on a 0- to 10-point scale, where 0 = no pain and 10 = worst pain) at rest and with activity at 24 hours after surgery and analgesic consumption of volume of epidural analgesic solution for the first 24 hours after surgery.

RESULTS

No correlation was found between BMI and postoperative spontaneous circulating cytokine levels. However, after activation of blood leukocytes with lipopolysaccharide, there was a significant positive correlation between the BMI and IL-1β, IL-6, and TNF-α levels (r = 0.26-0.32; p = 0.03, p = 0.03, and p = 0.01, respectively), suggesting priming of the innate immune system in obesity and potential for excessive postoperative inflammatory response. Obesity was not associated with increased pain or analgesic consumption in the first 24 hours after surgery.

CONCLUSIONS

Obesity is associated with a proinflammatory state after THA as demonstrated by enhanced cytokine reactivity. Larger studies exploring the specific impact of obesity and inflammation on surgical outcomes, including pain, are warranted.

LEVEL OF EVIDENCE

Level II, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Caring for the patient with obstructive sleep apnea: implications for health care providers in postanesthesia care

Obstructive sleep apnea (OSA) is a sleep disorder affecting 18 million Americans. The prevalence of OSA is increasing due to an epidemic rise in obesity, which is a major contributing factor. The primary treatment for OSA is continuous positive airway pressure, designed to maintain a patent airway for unobstructed breathing. OSA patients may experience postoperative hypoventilation due to residual anesthetic, analgesic requirements, and other comorbidities. Postoperative health care providers must be prepared to assess for hypoventilation and intervene using evidence-based interventions to improve outcomes. It is incumbent that the PACU nurse be aware of and implement evidence-based clinical guidelines for patients with OSA. Therefore, the purpose of this manuscript is to (1) describe the physiology, comorbidities, diagnosis, and treatment of OSA; (2) identify the effects of anesthesia in persons with OSA; (3) discuss clinical guidelines; and (4) describe implications for care in an effort to improve health outcomes in persons with OSA during the perianesthesia period.

Anesthetic considerations for abdominal wall reconstructive surgery

Anesthesia considerations for abdominal wall reconstruction (AWR) are numerous and depend upon the medical status of the patient and the projected procedure. Obesity, sleep apnea, hypertension, and cardiovascular disease are not uncommon in patients with abdominal wall defects; pulmonary functions and cardiac output can be affected by the surgical procedure. Patients with chronic obstructive pulmonary disease are also at a higher risk of coughing during the postoperative awakening process, which can compromise the reconstruction of the fascia. Given the increased complexity of the patients presenting for AWR, and the importance of the anesthesia for these specific procedures, it is important that surgeons are aware of the challenges that anesthesiologists face when treating these patients. Some of these challenges and their resolution are reviewed here.

Association between self reported snoring, STOP questionnaire and postoperative pulmonary complications in patients submitted to ortophaedic surgery

Background

Obstructive sleep apnea (OSA) may increase perioperative complications. The aim of this study was to determine the relationship among postoperative pulmonary complication, snoring and STOP questionnaire in patients with ortophaedic surgery.

Methods

1,406 consecutive records of patients who had undergone elective ortophaedic surgery during the period January 2005-December 2008 were investigated retrospectively. Demographic information, sleep symptoms, STOP questionnaire, comorbidities and outcome data were collected.

Results

There were 289 (20.5%) snorers and 1,117 (79.5%) non-snorers in the study group. There was no significant difference between snorer and non-snorer patients (p > 0.05) in the prevalence of pneumonia and respiratory failure. But in snorer patients the rate of postoperative atelectasis was significantly higher than in non-snorer group (p < 0.0001). The STOP Questionnaire was given to 1,406 patients and 147 (10.4%) out of them were classified at high risk of OSA. There was no significant difference in the prevalence of pneumonia and respiratory failure between low and high risk group (p > 0.05). However, in high risk patients the occurrence of postoperative atelectasis was significantly higher than in low risk group (p < 0.0001).

Conclusion

Postoperative atelectasis was significantly more prevalent in the high risk group according to STOP questionnaire.

Posterior lumbar spinal fusion and instrumentation in morbidly obese patients using the Synframe retractor system: technical note

PURPOSE

Lumbar spine surgery in morbidly obese patients is a challenge to the operating surgeon. The aim of the study was to evaluate the surgical experience in this group of patients using the Synframe retractor system (Synthes, Paoli, PA, USA) as a tool for improved surgical access.

METHODS

An Institutional Review Board approved retrospective study was conducted on 43 morbidly obese patients undergoing posterior lumbar decompression instrumentation and fusion. Patient selection was based on a BMI of >40. Information acquired included BMI, set up time, procedure time, ASA, intraoperative blood loss and the number of preoperative co-morbidities of each patient. Postoperative complications, length of stay, and pre-operative and postoperative Oswestry disability index (ODI) and visual analogue scale (VAS) were recorded at each postoperative visit. They were compared to 45 age matched controls from our spine database.

RESULTS

The average set-up time (73.5 min), amount of blood loss (average 1,040 mL), length of incision (10.3-14.5 cm) and length of hospital stay (5.4 days) were recorded. The average surgical time was dependent on the procedure and number of levels fused and ranged from 164 to 245 min. These parameters were compared with normal weight patients and noted to be higher.

CONCLUSION

The surgical experience determined that the Synframe retractor system provided a stable and well-illuminated operative field. It minimized the number of personnel required for assistance and improved surgical access. As may be expected, all the above recorded parameters were greater in the morbidly obese group.