Article Notes

• Hide
  • Pearls
  • Summaries
  • Comments

summary
1
In this review of published perimortem caesarean section cases more than half of the mothers survived to hospital discharge and almost 80% of these with favourable neurological outcome.
PM caesarean section was considered beneficial in 32% of cases.
Einav S, Kaufman N, Sela HY. Maternal cardiac arrest and perimortem caesarean delivery: evidence or expert-based? Resuscitation. 2012 Oct 1;83(10):1191-200.
  Daniel Jolley
pearl
1
Although DBS is more sensitive than TOFC, manual assessment of DBS fade can only detect residual paralysis at TOF ratio < 0.7.
Ueda N, Muteki T, Tsuda H et al. Is the diagnosis of significant residual neuromuscular blockade improved by using double-burst nerve stimulation? Eur J Anaesthesiol. 1991 May 1;8(3):213-8.
  Daniel Jolley
summary
0
The 5-second Head Lift Test and the Tongue Depressor Test, often used to detect PORC in the PACU are of limited use for detecting TOFR < 0.9, having sensitivities of only 11% and 13% and specificities of 87% and 90% respectively.
The Head Lift Test cannot identify POCR with a TOFR > 0.5. Debaene’s study population demonstrated Positive and Negative Predictive Values of the Head Lift and Tongue Depressor Tests of only 53-58%!
Subjective, qualitative neuromuscular monitors fare no better: Tactile TOF Fade and Double Burst Stimulation (DBS) have similar sensitivities (11% and 13% respectively), although high specificities (99% each). This provides a good Positive Predictive Value (93% & 97%) but a very poor Negative Predictive Value (57% & 58%) (depending on the incidence of PORC).
Debaene B, Plaud B, Dilly MP et al. Residual paralysis in the PACU after a single intubating dose of nondepolarizing muscle relaxant with an intermediate duration of action. Anesthesiology. 2003 May 1;98(5):1042-8.
  Daniel Jolley
summary
0
Videira identified that in addition to the interval since last NMBD, anesthetists commonly used the adequacy of spontaneous minute ventilation as a decision heuristic for deciding on the need for reversal.
“The adequacy of the breathing pattern was also cited heavily … This visual cue may be erroneously interpreted as a sufficient sign for tracheal extubation, instead of a necessary one. This heuristic assesses function of the diaphragm, not of the upper airway muscles.”
Videira RL Vieira JE. What rules of thumb do clinicians use to decide whether to antagonize nondepolarizing neuromuscular blocking drugs? Anesth. Analg. 2011 Nov 1;113(5):1192-6.
  Daniel Jolley
summary
0
The authors conclude that one-quarter of PACU desaturations below 90%, almost-half of desaturations below 80%, and almost one-third of re-intubations could be attributable to intermediate NMBD.
Grosse-Sundrup M, Henneman JP, Sandberg WS et al. Intermediate acting non-depolarizing neuromuscular blocking agents and risk of postoperative respiratory complications: prospective propensity score matched cohort study. BMJ. 2012 Jan 1;345:e6329.
  Daniel Jolley
comment
1
Interestingly, they found the risk of respiratory complications to be greater in those having shorter procedures (< 2 hours) presumably because of the shorter time between relaxant and extubation.
Grosse-Sundrup M, Henneman JP, Sandberg WS et al. Intermediate acting non-depolarizing neuromuscular blocking agents and risk of postoperative respiratory complications: prospective propensity score matched cohort study. BMJ. 2012 Jan 1;345:e6329.
  Daniel Jolley
comment
0
This is a very significant and large study, and should give us pause to ponder the consequences of invasive airway management and surgery requiring muscle relaxation. It is also important to note that qualitative neuromuscular monitoring (as opposed to quantitative) appears to offer no risk reduction, consistent with other research in this area.
Nonetheless, the retrospective nature of this study means these relationships should not necessarily be viewed as causal. This is not a study of an intervention per se, but the association between certain perioperative characteristics that may be unavoidable (e.g. using muscle relaxants).
An important paper for any concerned anaesthetist or anesthesiologist to read in full.
Grosse-Sundrup M, Henneman JP, Sandberg WS et al. Intermediate acting non-depolarizing neuromuscular blocking agents and risk of postoperative respiratory complications: prospective propensity score matched cohort study. BMJ. 2012 Jan 1;345:e6329.
  Daniel Jolley
summary
1
This very large cohort study demonstrated an association between use of intermediate-duration NMBD and risk of postoperative desaturation and reintubation requiring ICU admission, and a similar association with these outcomes and neostigmine reversal.
Qualitative neuromuscular monitoring did not reduce this risk.
Study population was all patients at Massachusetts General Hospital undergoing general anaesthesia including a muscle relaxant over a 4 year period, and who were extubated at the end of the procedure.
Grosse-Sundrup M, Henneman JP, Sandberg WS et al. Intermediate acting non-depolarizing neuromuscular blocking agents and risk of postoperative respiratory complications: prospective propensity score matched cohort study. BMJ. 2012 Jan 1;345:e6329.
  Daniel Jolley
pearl
1
Post-operative residual paralysis is associated with a greater incidence of desaturation in the post-anaesthesia care unit.
Sauer M, Stahn A, Soltesz S et al. The influence of residual neuromuscular block on the incidence of critical respiratory events. A randomised, prospective, placebo-controlled trial. Eur J Anaesthesiol. 2011 Dec 1; 28 (12): 842-8.
  Daniel Jolley
pearl
1
Partial paralysis with TOFR < 0.9 causes pharyngeal dysfunction and misdirected swallowing, increasing the risk of aspiration.
Sundman E, Witt H, Olsson R et al. The incidence and mechanisms of pharyngeal and upper esophageal dysfunction in partially paralyzed humans: pharyngeal videoradiography and simultaneous manometry after atracurium. Anesthesiology. 2000 Apr 1;92(4):977-84.
  Daniel Jolley