The population of the United States (US) is growing and aging.The US Census Bureau projects that the number of Americans age 65 years and older will more than double between 2010 and 2050. The percentage of Americans 65 and older will grow from 13% to more than 20% of the total population by 2030, and the fastest growing segment of this group (individuals 85 years and older) is expected to triple in number over the next 4 decades.These changes in the age demographics of the US population are largely due to people living longer and the “baby boomer” generation

https://www.journalacs.org/article/S1072-7515(12)00493-0/pdf

Optimal preoperative assessment of the geriatric surgical patient: a best practices guideline from the American College of Surgeons National Surgical Quality Improvement Program and the American Geriatrics Society.

BACKGROUND:Incomplete recovery of neuromuscular function may impair pulmonary and upper airway function and contribute to adverse respiratory events in the postanesthesia care unit (PACU). The aim of this investigation was to assess and quantify the severity of neuromuscular blockade in patients wit

Residual neuromuscular blockade and critical respiratory events in the postanesthesia care unit

Postoperative pulmonary complications are an important part of the risk of surgery and prolong the hospital stay by an average of one to two weeks.1 Much of the literature on the assessment of perioperative risk has focused on identifying the now well-defined cardiac risk factors. However, clinically significant postoperative pulmonary complications are as common as postoperative cardiac complications. According to one review, pulmonary complications were at least as common as or more common than cardiac complications in 17 of 25 studies of postoperative complications.2 This article reviews patient- and procedure-related risk factors, clinical evaluation, pulmonary-function testing, and risk-reduction strategies. The . . .

https://www.nejm.org/doi/pdf/10.1056/NEJM199903253401207

Preoperative Pulmonary Evaluation

This background review supports the American College of Physicians' clinical practice guideline on reducing postoperative pulmonary complications after noncardiothoracic surgery.

/pdf/strategies-to-reduce-postoperative-pulmonary-complications-4r1g29pr7u.pdf

Strategies to reduce postoperative pulmonary complications after noncardiothoracic surgery: systematic review for the American College of Physicians.

Background: Residual neuromuscular blockade remains a problem even after short surgical procedures. The train-of-four (TOF) ratio at the adductor pollicis required to avoid residual paralysis is now considered to be at least 0.9. The incidence of residual paralysis using this new threshold is not known, especially after a single intubating dose of intermediate-duration nondepolarizing relaxant. Therefore, the aim of the study was to determine the incidence of residual paralysis in the postanesthesia care unit after a single intubating dose of twice the ED95 of a nondepolarizing muscle relaxant with an intermediate duration of action. Methods: Five hundred twenty-six patients were enrolled. They received a single dose of vecuronium, rocuronium, or atracurium to facilitate tracheal intubation and received no more relaxant thereafter. Neuromuscular blockade was not reversed at the end of the procedure. On arrival in the postanesthesia care unit, the TOF ratio was measured at the adductor pollicis, using acceleromyography. Head lift, tongue depressor test, and manual assessment of TOF and DBS fade were also performed. The time delay between the injection of muscle relaxant and quantitative measurement of neuromuscular blockade was calculated from computerized anesthetic records. Results: The TOF ratios less than 0.7 and 0.9 were observed in 16% and 45% of the patients, respectively. Two hundred thirtynine patients were teste d2ho rmore after the administration of the muscle relaxant. Ten percent of these patients had a TOF ratio less than 0.7, and 37% had a TOF ratio less than 0.9. Clinical tests (head lift and tongue depressor) and manual assessment of fade showed a poor sensitivity (11–14%) to detect residual blockade (TOF < 0.9). Conclusion: After a single dose of intermediate-duration muscle relaxant and no reversal, residual paralysis is common, even more than 2 h after the administration of muscle relaxant. Quantitative measurement of neuromuscular transmission is the only recommended method to diagnose residual block.

Residual paralysis in the PACU after a single intubating dose of nondepolarizing muscle relaxant with an intermediate duration of action.

Background: After anaesthesia involving pancuronium a high incidence of both residual neuromuscular block and postoperative pulmonary complications (POPC) has been reported. The aim of this study was to compare the incidence of POPC following the use of pancuronium, atracurium, and vecuronium, and to examine the effect of residual neuromuscular block on the incidence of POPC.

Methods: A total of 691 adult patients undergoing abdominal, gynaecological, or orthopaedic surgery under general anaesthesia were randomised to receive either pancuronium, atracurium, or vecuronium. Perioperatively, the response to train-of-four (TOF) nerve stimulation was evaluated manually. Post-operatively, the TOF ratios were measured mechanomyograph-ically, and through a 6-day follow-up the patients were examined for pulmonary complications.

Results: The incidence of residual block, defined as a TOF ratio <0.7, was significantly higher in the pancuronium group (59/226: 26%) than in the atracurium/vecuronium groups (24/450: 5.3%). In the pancuronium group, significantly more patients with residual block developed POPC (10/59: 16.9%) as compared to patients without residual block (8/167 4.8%). In the atracurium/vecuronium groups, the incidence of POPC was not significantly different in patients with (1/24: 4.2%) or without (23/426: 5.4%) residual block. Multiple regression analysis indicated that abdominal surgery, age, long-lasting surgery, and a TOF ratio<0.7 following the use of pancuronium were potential risk factors for the development of POPC.

Conclusion: Postoperative residual block caused by pancuronium is a significant risk factor for development of POPC.

Residual neuromuscular block is a risk factor for postoperative pulmonary complications: A prospective, randomised, and blinded study of postoperative pulmonary complications after atracurium, vecuronium and pancuronium

Background: The short duration of action of mivacurium is due to its rapid hydrolysis by plasma cholinesterase (pChe). In patients with normal phenotype, low pChe activity because of, for instance, disease or intake of drugs may prolong the duration of action of mivacurium. The purpose of this study was to evaluate the relationship between pChe activity and the duration of action of mivacurium 0.2 mg/kg in phenotypically normal patients.



Material: Forty-three adult patients with normal pChe phenotype and low or normal pChe activity, undergoing a variety of surgical procedures were included in the study with their informed consent and Ethics Committee approval. The neuromuscular block was monitored using TOF stimulation every 12 s and mechanomyography. The time to reappearance of the first response to TOF stimulation was measured.



Results: The patients pChe activities ranged from 45 to 1272 U/l (normal range 660–1620 U/l) and the time to first response to TOF from 8.1 to 62.7 min. An inverse relationship between enzyme activity and duration of action of mivacurium was found. The relationship was described by the equation: log10 (time) =α- β log10 (pChe), where α (SD) is 2.547 (0.186) and β (SD) 0.454 (0.069).



Conclusion: In patients with phenotypically normal pChe, prediction of the duration of action of mivacurium is possible from the patients actual pChe activity. In patients with pChe activities below the normal range, the time to reappearance of the first response to TOF stimulation may vary from 10 to 180 min Only patients with pChe activities <220 U/l had a significantly prolonged duration of action of mivacurium.

L. T. Skovgaard

Papers

Residual neuromuscular block is a risk factor for postoperative pulmonary complications: A prospective, randomised, and blinded study of postoperative pulmonary complications after atracurium, vecuronium and pancuronium

Plasma cholinesterase activity and duration of action of mivacurium in phenotypically normal patients.